1// SPDX-License-Identifier: GPL-2.0 2/* 3 * ring buffer based function tracer 4 * 5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> 6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> 7 * 8 * Based on code from the latency_tracer, that is: 9 * 10 * Copyright (C) 2004-2006 Ingo Molnar 11 * Copyright (C) 2004 Nadia Yvette Chambers 12 */ 13#include <linux/ring_buffer.h> 14#include <linux/debugfs.h> 15#include <linux/uaccess.h> 16#include <linux/ftrace.h> 17#include <linux/slab.h> 18#include <linux/fs.h> 19 20#include "trace.h" 21 22static void tracing_start_function_trace(struct trace_array *tr); 23static void tracing_stop_function_trace(struct trace_array *tr); 24static void 25function_trace_call(unsigned long ip, unsigned long parent_ip, 26 struct ftrace_ops *op, struct ftrace_regs *fregs); 27static void 28function_stack_trace_call(unsigned long ip, unsigned long parent_ip, 29 struct ftrace_ops *op, struct ftrace_regs *fregs); 30static void 31function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip, 32 struct ftrace_ops *op, struct ftrace_regs *fregs); 33static void 34function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip, 35 struct ftrace_ops *op, 36 struct ftrace_regs *fregs); 37static struct tracer_flags func_flags; 38 39/* Our option */ 40enum { 41 42 TRACE_FUNC_NO_OPTS = 0x0, /* No flags set. */ 43 TRACE_FUNC_OPT_STACK = 0x1, 44 TRACE_FUNC_OPT_NO_REPEATS = 0x2, 45 46 /* Update this to next highest bit. */ 47 TRACE_FUNC_OPT_HIGHEST_BIT = 0x4 48}; 49 50#define TRACE_FUNC_OPT_MASK (TRACE_FUNC_OPT_HIGHEST_BIT - 1) 51 52int ftrace_allocate_ftrace_ops(struct trace_array *tr) 53{ 54 struct ftrace_ops *ops; 55 56 /* The top level array uses the "global_ops" */ 57 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) 58 return 0; 59 60 ops = kzalloc(sizeof(*ops), GFP_KERNEL); 61 if (!ops) 62 return -ENOMEM; 63 64 /* Currently only the non stack version is supported */ 65 ops->func = function_trace_call; 66 ops->flags = FTRACE_OPS_FL_PID; 67 68 tr->ops = ops; 69 ops->private = tr; 70 71 return 0; 72} 73 74void ftrace_free_ftrace_ops(struct trace_array *tr) 75{ 76 kfree(tr->ops); 77 tr->ops = NULL; 78} 79 80int ftrace_create_function_files(struct trace_array *tr, 81 struct dentry *parent) 82{ 83 /* 84 * The top level array uses the "global_ops", and the files are 85 * created on boot up. 86 */ 87 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) 88 return 0; 89 90 if (!tr->ops) 91 return -EINVAL; 92 93 ftrace_create_filter_files(tr->ops, parent); 94 95 return 0; 96} 97 98void ftrace_destroy_function_files(struct trace_array *tr) 99{ 100 ftrace_destroy_filter_files(tr->ops); 101 ftrace_free_ftrace_ops(tr); 102} 103 104static ftrace_func_t select_trace_function(u32 flags_val) 105{ 106 switch (flags_val & TRACE_FUNC_OPT_MASK) { 107 case TRACE_FUNC_NO_OPTS: 108 return function_trace_call; 109 case TRACE_FUNC_OPT_STACK: 110 return function_stack_trace_call; 111 case TRACE_FUNC_OPT_NO_REPEATS: 112 return function_no_repeats_trace_call; 113 case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS: 114 return function_stack_no_repeats_trace_call; 115 default: 116 return NULL; 117 } 118} 119 120static bool handle_func_repeats(struct trace_array *tr, u32 flags_val) 121{ 122 if (!tr->last_func_repeats && 123 (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) { 124 tr->last_func_repeats = alloc_percpu(struct trace_func_repeats); 125 if (!tr->last_func_repeats) 126 return false; 127 } 128 129 return true; 130} 131 132static int function_trace_init(struct trace_array *tr) 133{ 134 ftrace_func_t func; 135 /* 136 * Instance trace_arrays get their ops allocated 137 * at instance creation. Unless it failed 138 * the allocation. 139 */ 140 if (!tr->ops) 141 return -ENOMEM; 142 143 func = select_trace_function(func_flags.val); 144 if (!func) 145 return -EINVAL; 146 147 if (!handle_func_repeats(tr, func_flags.val)) 148 return -ENOMEM; 149 150 ftrace_init_array_ops(tr, func); 151 152 tr->array_buffer.cpu = raw_smp_processor_id(); 153 154 tracing_start_cmdline_record(); 155 tracing_start_function_trace(tr); 156 return 0; 157} 158 159static void function_trace_reset(struct trace_array *tr) 160{ 161 tracing_stop_function_trace(tr); 162 tracing_stop_cmdline_record(); 163 ftrace_reset_array_ops(tr); 164} 165 166static void function_trace_start(struct trace_array *tr) 167{ 168 tracing_reset_online_cpus(&tr->array_buffer); 169} 170 171static void 172function_trace_call(unsigned long ip, unsigned long parent_ip, 173 struct ftrace_ops *op, struct ftrace_regs *fregs) 174{ 175 struct trace_array *tr = op->private; 176 struct trace_array_cpu *data; 177 unsigned int trace_ctx; 178 int bit; 179 int cpu; 180 181 if (unlikely(!tr->function_enabled)) 182 return; 183 184 bit = ftrace_test_recursion_trylock(ip, parent_ip); 185 if (bit < 0) 186 return; 187 188 trace_ctx = tracing_gen_ctx(); 189 190 cpu = smp_processor_id(); 191 data = per_cpu_ptr(tr->array_buffer.data, cpu); 192 if (!atomic_read(&data->disabled)) 193 trace_function(tr, ip, parent_ip, trace_ctx); 194 195 ftrace_test_recursion_unlock(bit); 196} 197 198#ifdef CONFIG_UNWINDER_ORC 199/* 200 * Skip 2: 201 * 202 * function_stack_trace_call() 203 * ftrace_call() 204 */ 205#define STACK_SKIP 2 206#else 207/* 208 * Skip 3: 209 * __trace_stack() 210 * function_stack_trace_call() 211 * ftrace_call() 212 */ 213#define STACK_SKIP 3 214#endif 215 216static void 217function_stack_trace_call(unsigned long ip, unsigned long parent_ip, 218 struct ftrace_ops *op, struct ftrace_regs *fregs) 219{ 220 struct trace_array *tr = op->private; 221 struct trace_array_cpu *data; 222 unsigned long flags; 223 long disabled; 224 int cpu; 225 unsigned int trace_ctx; 226 227 if (unlikely(!tr->function_enabled)) 228 return; 229 230 /* 231 * Need to use raw, since this must be called before the 232 * recursive protection is performed. 233 */ 234 local_irq_save(flags); 235 cpu = raw_smp_processor_id(); 236 data = per_cpu_ptr(tr->array_buffer.data, cpu); 237 disabled = atomic_inc_return(&data->disabled); 238 239 if (likely(disabled == 1)) { 240 trace_ctx = tracing_gen_ctx_flags(flags); 241 trace_function(tr, ip, parent_ip, trace_ctx); 242 __trace_stack(tr, trace_ctx, STACK_SKIP); 243 } 244 245 atomic_dec(&data->disabled); 246 local_irq_restore(flags); 247} 248 249static inline bool is_repeat_check(struct trace_array *tr, 250 struct trace_func_repeats *last_info, 251 unsigned long ip, unsigned long parent_ip) 252{ 253 if (last_info->ip == ip && 254 last_info->parent_ip == parent_ip && 255 last_info->count < U16_MAX) { 256 last_info->ts_last_call = 257 ring_buffer_time_stamp(tr->array_buffer.buffer); 258 last_info->count++; 259 return true; 260 } 261 262 return false; 263} 264 265static inline void process_repeats(struct trace_array *tr, 266 unsigned long ip, unsigned long parent_ip, 267 struct trace_func_repeats *last_info, 268 unsigned int trace_ctx) 269{ 270 if (last_info->count) { 271 trace_last_func_repeats(tr, last_info, trace_ctx); 272 last_info->count = 0; 273 } 274 275 last_info->ip = ip; 276 last_info->parent_ip = parent_ip; 277} 278 279static void 280function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip, 281 struct ftrace_ops *op, 282 struct ftrace_regs *fregs) 283{ 284 struct trace_func_repeats *last_info; 285 struct trace_array *tr = op->private; 286 struct trace_array_cpu *data; 287 unsigned int trace_ctx; 288 unsigned long flags; 289 int bit; 290 int cpu; 291 292 if (unlikely(!tr->function_enabled)) 293 return; 294 295 bit = ftrace_test_recursion_trylock(ip, parent_ip); 296 if (bit < 0) 297 return; 298 299 cpu = smp_processor_id(); 300 data = per_cpu_ptr(tr->array_buffer.data, cpu); 301 if (atomic_read(&data->disabled)) 302 goto out; 303 304 /* 305 * An interrupt may happen at any place here. But as far as I can see, 306 * the only damage that this can cause is to mess up the repetition 307 * counter without valuable data being lost. 308 * TODO: think about a solution that is better than just hoping to be 309 * lucky. 310 */ 311 last_info = per_cpu_ptr(tr->last_func_repeats, cpu); 312 if (is_repeat_check(tr, last_info, ip, parent_ip)) 313 goto out; 314 315 local_save_flags(flags); 316 trace_ctx = tracing_gen_ctx_flags(flags); 317 process_repeats(tr, ip, parent_ip, last_info, trace_ctx); 318 319 trace_function(tr, ip, parent_ip, trace_ctx); 320 321out: 322 ftrace_test_recursion_unlock(bit); 323} 324 325static void 326function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip, 327 struct ftrace_ops *op, 328 struct ftrace_regs *fregs) 329{ 330 struct trace_func_repeats *last_info; 331 struct trace_array *tr = op->private; 332 struct trace_array_cpu *data; 333 unsigned long flags; 334 long disabled; 335 int cpu; 336 unsigned int trace_ctx; 337 338 if (unlikely(!tr->function_enabled)) 339 return; 340 341 /* 342 * Need to use raw, since this must be called before the 343 * recursive protection is performed. 344 */ 345 local_irq_save(flags); 346 cpu = raw_smp_processor_id(); 347 data = per_cpu_ptr(tr->array_buffer.data, cpu); 348 disabled = atomic_inc_return(&data->disabled); 349 350 if (likely(disabled == 1)) { 351 last_info = per_cpu_ptr(tr->last_func_repeats, cpu); 352 if (is_repeat_check(tr, last_info, ip, parent_ip)) 353 goto out; 354 355 trace_ctx = tracing_gen_ctx_flags(flags); 356 process_repeats(tr, ip, parent_ip, last_info, trace_ctx); 357 358 trace_function(tr, ip, parent_ip, trace_ctx); 359 __trace_stack(tr, trace_ctx, STACK_SKIP); 360 } 361 362 out: 363 atomic_dec(&data->disabled); 364 local_irq_restore(flags); 365} 366 367static struct tracer_opt func_opts[] = { 368#ifdef CONFIG_STACKTRACE 369 { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, 370#endif 371 { TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) }, 372 { } /* Always set a last empty entry */ 373}; 374 375static struct tracer_flags func_flags = { 376 .val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */ 377 .opts = func_opts 378}; 379 380static void tracing_start_function_trace(struct trace_array *tr) 381{ 382 tr->function_enabled = 0; 383 register_ftrace_function(tr->ops); 384 tr->function_enabled = 1; 385} 386 387static void tracing_stop_function_trace(struct trace_array *tr) 388{ 389 tr->function_enabled = 0; 390 unregister_ftrace_function(tr->ops); 391} 392 393static struct tracer function_trace; 394 395static int 396func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 397{ 398 ftrace_func_t func; 399 u32 new_flags; 400 401 /* Do nothing if already set. */ 402 if (!!set == !!(func_flags.val & bit)) 403 return 0; 404 405 /* We can change this flag only when not running. */ 406 if (tr->current_trace != &function_trace) 407 return 0; 408 409 new_flags = (func_flags.val & ~bit) | (set ? bit : 0); 410 func = select_trace_function(new_flags); 411 if (!func) 412 return -EINVAL; 413 414 /* Check if there's anything to change. */ 415 if (tr->ops->func == func) 416 return 0; 417 418 if (!handle_func_repeats(tr, new_flags)) 419 return -ENOMEM; 420 421 unregister_ftrace_function(tr->ops); 422 tr->ops->func = func; 423 register_ftrace_function(tr->ops); 424 425 return 0; 426} 427 428static struct tracer function_trace __tracer_data = 429{ 430 .name = "function", 431 .init = function_trace_init, 432 .reset = function_trace_reset, 433 .start = function_trace_start, 434 .flags = &func_flags, 435 .set_flag = func_set_flag, 436 .allow_instances = true, 437#ifdef CONFIG_FTRACE_SELFTEST 438 .selftest = trace_selftest_startup_function, 439#endif 440}; 441 442#ifdef CONFIG_DYNAMIC_FTRACE 443static void update_traceon_count(struct ftrace_probe_ops *ops, 444 unsigned long ip, 445 struct trace_array *tr, bool on, 446 void *data) 447{ 448 struct ftrace_func_mapper *mapper = data; 449 long *count; 450 long old_count; 451 452 /* 453 * Tracing gets disabled (or enabled) once per count. 454 * This function can be called at the same time on multiple CPUs. 455 * It is fine if both disable (or enable) tracing, as disabling 456 * (or enabling) the second time doesn't do anything as the 457 * state of the tracer is already disabled (or enabled). 458 * What needs to be synchronized in this case is that the count 459 * only gets decremented once, even if the tracer is disabled 460 * (or enabled) twice, as the second one is really a nop. 461 * 462 * The memory barriers guarantee that we only decrement the 463 * counter once. First the count is read to a local variable 464 * and a read barrier is used to make sure that it is loaded 465 * before checking if the tracer is in the state we want. 466 * If the tracer is not in the state we want, then the count 467 * is guaranteed to be the old count. 468 * 469 * Next the tracer is set to the state we want (disabled or enabled) 470 * then a write memory barrier is used to make sure that 471 * the new state is visible before changing the counter by 472 * one minus the old counter. This guarantees that another CPU 473 * executing this code will see the new state before seeing 474 * the new counter value, and would not do anything if the new 475 * counter is seen. 476 * 477 * Note, there is no synchronization between this and a user 478 * setting the tracing_on file. But we currently don't care 479 * about that. 480 */ 481 count = (long *)ftrace_func_mapper_find_ip(mapper, ip); 482 old_count = *count; 483 484 if (old_count <= 0) 485 return; 486 487 /* Make sure we see count before checking tracing state */ 488 smp_rmb(); 489 490 if (on == !!tracer_tracing_is_on(tr)) 491 return; 492 493 if (on) 494 tracer_tracing_on(tr); 495 else 496 tracer_tracing_off(tr); 497 498 /* Make sure tracing state is visible before updating count */ 499 smp_wmb(); 500 501 *count = old_count - 1; 502} 503 504static void 505ftrace_traceon_count(unsigned long ip, unsigned long parent_ip, 506 struct trace_array *tr, struct ftrace_probe_ops *ops, 507 void *data) 508{ 509 update_traceon_count(ops, ip, tr, 1, data); 510} 511 512static void 513ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, 514 struct trace_array *tr, struct ftrace_probe_ops *ops, 515 void *data) 516{ 517 update_traceon_count(ops, ip, tr, 0, data); 518} 519 520static void 521ftrace_traceon(unsigned long ip, unsigned long parent_ip, 522 struct trace_array *tr, struct ftrace_probe_ops *ops, 523 void *data) 524{ 525 if (tracer_tracing_is_on(tr)) 526 return; 527 528 tracer_tracing_on(tr); 529} 530 531static void 532ftrace_traceoff(unsigned long ip, unsigned long parent_ip, 533 struct trace_array *tr, struct ftrace_probe_ops *ops, 534 void *data) 535{ 536 if (!tracer_tracing_is_on(tr)) 537 return; 538 539 tracer_tracing_off(tr); 540} 541 542#ifdef CONFIG_UNWINDER_ORC 543/* 544 * Skip 3: 545 * 546 * function_trace_probe_call() 547 * ftrace_ops_assist_func() 548 * ftrace_call() 549 */ 550#define FTRACE_STACK_SKIP 3 551#else 552/* 553 * Skip 5: 554 * 555 * __trace_stack() 556 * ftrace_stacktrace() 557 * function_trace_probe_call() 558 * ftrace_ops_assist_func() 559 * ftrace_call() 560 */ 561#define FTRACE_STACK_SKIP 5 562#endif 563 564static __always_inline void trace_stack(struct trace_array *tr) 565{ 566 unsigned int trace_ctx; 567 568 trace_ctx = tracing_gen_ctx(); 569 570 __trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP); 571} 572 573static void 574ftrace_stacktrace(unsigned long ip, unsigned long parent_ip, 575 struct trace_array *tr, struct ftrace_probe_ops *ops, 576 void *data) 577{ 578 trace_stack(tr); 579} 580 581static void 582ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, 583 struct trace_array *tr, struct ftrace_probe_ops *ops, 584 void *data) 585{ 586 struct ftrace_func_mapper *mapper = data; 587 long *count; 588 long old_count; 589 long new_count; 590 591 if (!tracing_is_on()) 592 return; 593 594 /* unlimited? */ 595 if (!mapper) { 596 trace_stack(tr); 597 return; 598 } 599 600 count = (long *)ftrace_func_mapper_find_ip(mapper, ip); 601 602 /* 603 * Stack traces should only execute the number of times the 604 * user specified in the counter. 605 */ 606 do { 607 old_count = *count; 608 609 if (!old_count) 610 return; 611 612 new_count = old_count - 1; 613 new_count = cmpxchg(count, old_count, new_count); 614 if (new_count == old_count) 615 trace_stack(tr); 616 617 if (!tracing_is_on()) 618 return; 619 620 } while (new_count != old_count); 621} 622 623static int update_count(struct ftrace_probe_ops *ops, unsigned long ip, 624 void *data) 625{ 626 struct ftrace_func_mapper *mapper = data; 627 long *count = NULL; 628 629 if (mapper) 630 count = (long *)ftrace_func_mapper_find_ip(mapper, ip); 631 632 if (count) { 633 if (*count <= 0) 634 return 0; 635 (*count)--; 636 } 637 638 return 1; 639} 640 641static void 642ftrace_dump_probe(unsigned long ip, unsigned long parent_ip, 643 struct trace_array *tr, struct ftrace_probe_ops *ops, 644 void *data) 645{ 646 if (update_count(ops, ip, data)) 647 ftrace_dump(DUMP_ALL); 648} 649 650/* Only dump the current CPU buffer. */ 651static void 652ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, 653 struct trace_array *tr, struct ftrace_probe_ops *ops, 654 void *data) 655{ 656 if (update_count(ops, ip, data)) 657 ftrace_dump(DUMP_ORIG); 658} 659 660static int 661ftrace_probe_print(const char *name, struct seq_file *m, 662 unsigned long ip, struct ftrace_probe_ops *ops, 663 void *data) 664{ 665 struct ftrace_func_mapper *mapper = data; 666 long *count = NULL; 667 668 seq_printf(m, "%ps:%s", (void *)ip, name); 669 670 if (mapper) 671 count = (long *)ftrace_func_mapper_find_ip(mapper, ip); 672 673 if (count) 674 seq_printf(m, ":count=%ld\n", *count); 675 else 676 seq_puts(m, ":unlimited\n"); 677 678 return 0; 679} 680 681static int 682ftrace_traceon_print(struct seq_file *m, unsigned long ip, 683 struct ftrace_probe_ops *ops, 684 void *data) 685{ 686 return ftrace_probe_print("traceon", m, ip, ops, data); 687} 688 689static int 690ftrace_traceoff_print(struct seq_file *m, unsigned long ip, 691 struct ftrace_probe_ops *ops, void *data) 692{ 693 return ftrace_probe_print("traceoff", m, ip, ops, data); 694} 695 696static int 697ftrace_stacktrace_print(struct seq_file *m, unsigned long ip, 698 struct ftrace_probe_ops *ops, void *data) 699{ 700 return ftrace_probe_print("stacktrace", m, ip, ops, data); 701} 702 703static int 704ftrace_dump_print(struct seq_file *m, unsigned long ip, 705 struct ftrace_probe_ops *ops, void *data) 706{ 707 return ftrace_probe_print("dump", m, ip, ops, data); 708} 709 710static int 711ftrace_cpudump_print(struct seq_file *m, unsigned long ip, 712 struct ftrace_probe_ops *ops, void *data) 713{ 714 return ftrace_probe_print("cpudump", m, ip, ops, data); 715} 716 717 718static int 719ftrace_count_init(struct ftrace_probe_ops *ops, struct trace_array *tr, 720 unsigned long ip, void *init_data, void **data) 721{ 722 struct ftrace_func_mapper *mapper = *data; 723 724 if (!mapper) { 725 mapper = allocate_ftrace_func_mapper(); 726 if (!mapper) 727 return -ENOMEM; 728 *data = mapper; 729 } 730 731 return ftrace_func_mapper_add_ip(mapper, ip, init_data); 732} 733 734static void 735ftrace_count_free(struct ftrace_probe_ops *ops, struct trace_array *tr, 736 unsigned long ip, void *data) 737{ 738 struct ftrace_func_mapper *mapper = data; 739 740 if (!ip) { 741 free_ftrace_func_mapper(mapper, NULL); 742 return; 743 } 744 745 ftrace_func_mapper_remove_ip(mapper, ip); 746} 747 748static struct ftrace_probe_ops traceon_count_probe_ops = { 749 .func = ftrace_traceon_count, 750 .print = ftrace_traceon_print, 751 .init = ftrace_count_init, 752 .free = ftrace_count_free, 753}; 754 755static struct ftrace_probe_ops traceoff_count_probe_ops = { 756 .func = ftrace_traceoff_count, 757 .print = ftrace_traceoff_print, 758 .init = ftrace_count_init, 759 .free = ftrace_count_free, 760}; 761 762static struct ftrace_probe_ops stacktrace_count_probe_ops = { 763 .func = ftrace_stacktrace_count, 764 .print = ftrace_stacktrace_print, 765 .init = ftrace_count_init, 766 .free = ftrace_count_free, 767}; 768 769static struct ftrace_probe_ops dump_probe_ops = { 770 .func = ftrace_dump_probe, 771 .print = ftrace_dump_print, 772 .init = ftrace_count_init, 773 .free = ftrace_count_free, 774}; 775 776static struct ftrace_probe_ops cpudump_probe_ops = { 777 .func = ftrace_cpudump_probe, 778 .print = ftrace_cpudump_print, 779}; 780 781static struct ftrace_probe_ops traceon_probe_ops = { 782 .func = ftrace_traceon, 783 .print = ftrace_traceon_print, 784}; 785 786static struct ftrace_probe_ops traceoff_probe_ops = { 787 .func = ftrace_traceoff, 788 .print = ftrace_traceoff_print, 789}; 790 791static struct ftrace_probe_ops stacktrace_probe_ops = { 792 .func = ftrace_stacktrace, 793 .print = ftrace_stacktrace_print, 794}; 795 796static int 797ftrace_trace_probe_callback(struct trace_array *tr, 798 struct ftrace_probe_ops *ops, 799 struct ftrace_hash *hash, char *glob, 800 char *cmd, char *param, int enable) 801{ 802 void *count = (void *)-1; 803 char *number; 804 int ret; 805 806 /* hash funcs only work with set_ftrace_filter */ 807 if (!enable) 808 return -EINVAL; 809 810 if (glob[0] == '!') 811 return unregister_ftrace_function_probe_func(glob+1, tr, ops); 812 813 if (!param) 814 goto out_reg; 815 816 number = strsep(¶m, ":"); 817 818 if (!strlen(number)) 819 goto out_reg; 820 821 /* 822 * We use the callback data field (which is a pointer) 823 * as our counter. 824 */ 825 ret = kstrtoul(number, 0, (unsigned long *)&count); 826 if (ret) 827 return ret; 828 829 out_reg: 830 ret = register_ftrace_function_probe(glob, tr, ops, count); 831 832 return ret < 0 ? ret : 0; 833} 834 835static int 836ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash, 837 char *glob, char *cmd, char *param, int enable) 838{ 839 struct ftrace_probe_ops *ops; 840 841 if (!tr) 842 return -ENODEV; 843 844 /* we register both traceon and traceoff to this callback */ 845 if (strcmp(cmd, "traceon") == 0) 846 ops = param ? &traceon_count_probe_ops : &traceon_probe_ops; 847 else 848 ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops; 849 850 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd, 851 param, enable); 852} 853 854static int 855ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash, 856 char *glob, char *cmd, char *param, int enable) 857{ 858 struct ftrace_probe_ops *ops; 859 860 if (!tr) 861 return -ENODEV; 862 863 ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops; 864 865 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd, 866 param, enable); 867} 868 869static int 870ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash, 871 char *glob, char *cmd, char *param, int enable) 872{ 873 struct ftrace_probe_ops *ops; 874 875 if (!tr) 876 return -ENODEV; 877 878 ops = &dump_probe_ops; 879 880 /* Only dump once. */ 881 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd, 882 "1", enable); 883} 884 885static int 886ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash, 887 char *glob, char *cmd, char *param, int enable) 888{ 889 struct ftrace_probe_ops *ops; 890 891 if (!tr) 892 return -ENODEV; 893 894 ops = &cpudump_probe_ops; 895 896 /* Only dump once. */ 897 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd, 898 "1", enable); 899} 900 901static struct ftrace_func_command ftrace_traceon_cmd = { 902 .name = "traceon", 903 .func = ftrace_trace_onoff_callback, 904}; 905 906static struct ftrace_func_command ftrace_traceoff_cmd = { 907 .name = "traceoff", 908 .func = ftrace_trace_onoff_callback, 909}; 910 911static struct ftrace_func_command ftrace_stacktrace_cmd = { 912 .name = "stacktrace", 913 .func = ftrace_stacktrace_callback, 914}; 915 916static struct ftrace_func_command ftrace_dump_cmd = { 917 .name = "dump", 918 .func = ftrace_dump_callback, 919}; 920 921static struct ftrace_func_command ftrace_cpudump_cmd = { 922 .name = "cpudump", 923 .func = ftrace_cpudump_callback, 924}; 925 926static int __init init_func_cmd_traceon(void) 927{ 928 int ret; 929 930 ret = register_ftrace_command(&ftrace_traceoff_cmd); 931 if (ret) 932 return ret; 933 934 ret = register_ftrace_command(&ftrace_traceon_cmd); 935 if (ret) 936 goto out_free_traceoff; 937 938 ret = register_ftrace_command(&ftrace_stacktrace_cmd); 939 if (ret) 940 goto out_free_traceon; 941 942 ret = register_ftrace_command(&ftrace_dump_cmd); 943 if (ret) 944 goto out_free_stacktrace; 945 946 ret = register_ftrace_command(&ftrace_cpudump_cmd); 947 if (ret) 948 goto out_free_dump; 949 950 return 0; 951 952 out_free_dump: 953 unregister_ftrace_command(&ftrace_dump_cmd); 954 out_free_stacktrace: 955 unregister_ftrace_command(&ftrace_stacktrace_cmd); 956 out_free_traceon: 957 unregister_ftrace_command(&ftrace_traceon_cmd); 958 out_free_traceoff: 959 unregister_ftrace_command(&ftrace_traceoff_cmd); 960 961 return ret; 962} 963#else 964static inline int init_func_cmd_traceon(void) 965{ 966 return 0; 967} 968#endif /* CONFIG_DYNAMIC_FTRACE */ 969 970__init int init_function_trace(void) 971{ 972 init_func_cmd_traceon(); 973 return register_tracer(&function_trace); 974} 975