1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * trace irqs off critical timings 4 * 5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> 6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> 7 * 8 * From code in the latency_tracer, that is: 9 * 10 * Copyright (C) 2004-2006 Ingo Molnar 11 * Copyright (C) 2004 Nadia Yvette Chambers 12 */ 13 #include <linux/kallsyms.h> 14 #include <linux/uaccess.h> 15 #include <linux/module.h> 16 #include <linux/ftrace.h> 17 #include <linux/kprobes.h> 18 19 #include "trace.h" 20 21 #include <trace/events/preemptirq.h> 22 23 #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) 24 static struct trace_array *irqsoff_trace __read_mostly; 25 static int tracer_enabled __read_mostly; 26 27 static DEFINE_PER_CPU(int, tracing_cpu); 28 29 static DEFINE_RAW_SPINLOCK(max_trace_lock); 30 31 enum { 32 TRACER_IRQS_OFF = (1 << 1), 33 TRACER_PREEMPT_OFF = (1 << 2), 34 }; 35 36 static int trace_type __read_mostly; 37 38 static int save_flags; 39 40 static void stop_irqsoff_tracer(struct trace_array *tr, int graph); 41 static int start_irqsoff_tracer(struct trace_array *tr, int graph); 42 43 #ifdef CONFIG_PREEMPT_TRACER 44 static inline int 45 preempt_trace(int pc) 46 { 47 return ((trace_type & TRACER_PREEMPT_OFF) && pc); 48 } 49 #else 50 # define preempt_trace(pc) (0) 51 #endif 52 53 #ifdef CONFIG_IRQSOFF_TRACER 54 static inline int 55 irq_trace(void) 56 { 57 return ((trace_type & TRACER_IRQS_OFF) && 58 irqs_disabled()); 59 } 60 #else 61 # define irq_trace() (0) 62 #endif 63 64 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 65 static int irqsoff_display_graph(struct trace_array *tr, int set); 66 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH) 67 #else 68 static inline int irqsoff_display_graph(struct trace_array *tr, int set) 69 { 70 return -EINVAL; 71 } 72 # define is_graph(tr) false 73 #endif 74 75 /* 76 * Sequence count - we record it when starting a measurement and 77 * skip the latency if the sequence has changed - some other section 78 * did a maximum and could disturb our measurement with serial console 79 * printouts, etc. Truly coinciding maximum latencies should be rare 80 * and what happens together happens separately as well, so this doesn't 81 * decrease the validity of the maximum found: 82 */ 83 static __cacheline_aligned_in_smp unsigned long max_sequence; 84 85 #ifdef CONFIG_FUNCTION_TRACER 86 /* 87 * Prologue for the preempt and irqs off function tracers. 88 * 89 * Returns 1 if it is OK to continue, and data->disabled is 90 * incremented. 91 * 0 if the trace is to be ignored, and data->disabled 92 * is kept the same. 93 * 94 * Note, this function is also used outside this ifdef but 95 * inside the #ifdef of the function graph tracer below. 96 * This is OK, since the function graph tracer is 97 * dependent on the function tracer. 98 */ 99 static int func_prolog_dec(struct trace_array *tr, 100 struct trace_array_cpu **data, 101 unsigned long *flags) 102 { 103 long disabled; 104 int cpu; 105 106 /* 107 * Does not matter if we preempt. We test the flags 108 * afterward, to see if irqs are disabled or not. 109 * If we preempt and get a false positive, the flags 110 * test will fail. 111 */ 112 cpu = raw_smp_processor_id(); 113 if (likely(!per_cpu(tracing_cpu, cpu))) 114 return 0; 115 116 local_save_flags(*flags); 117 /* 118 * Slight chance to get a false positive on tracing_cpu, 119 * although I'm starting to think there isn't a chance. 120 * Leave this for now just to be paranoid. 121 */ 122 if (!irqs_disabled_flags(*flags) && !preempt_count()) 123 return 0; 124 125 *data = per_cpu_ptr(tr->array_buffer.data, cpu); 126 disabled = local_inc_return(&(*data)->disabled); 127 128 if (likely(disabled == 1)) 129 return 1; 130 131 local_dec(&(*data)->disabled); 132 133 return 0; 134 } 135 136 /* 137 * irqsoff uses its own tracer function to keep the overhead down: 138 */ 139 static void 140 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip, 141 struct ftrace_ops *op, struct ftrace_regs *fregs) 142 { 143 struct trace_array *tr = irqsoff_trace; 144 struct trace_array_cpu *data; 145 unsigned long flags; 146 unsigned int trace_ctx; 147 148 if (!func_prolog_dec(tr, &data, &flags)) 149 return; 150 151 trace_ctx = tracing_gen_ctx_flags(flags); 152 153 trace_function(tr, ip, parent_ip, trace_ctx, fregs); 154 155 local_dec(&data->disabled); 156 } 157 #endif /* CONFIG_FUNCTION_TRACER */ 158 159 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 160 static int irqsoff_display_graph(struct trace_array *tr, int set) 161 { 162 int cpu; 163 164 if (!(is_graph(tr) ^ set)) 165 return 0; 166 167 stop_irqsoff_tracer(irqsoff_trace, !set); 168 169 for_each_possible_cpu(cpu) 170 per_cpu(tracing_cpu, cpu) = 0; 171 172 tr->max_latency = 0; 173 tracing_reset_online_cpus(&irqsoff_trace->array_buffer); 174 175 return start_irqsoff_tracer(irqsoff_trace, set); 176 } 177 178 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace, 179 struct fgraph_ops *gops, 180 struct ftrace_regs *fregs) 181 { 182 struct trace_array *tr = irqsoff_trace; 183 struct trace_array_cpu *data; 184 unsigned long flags; 185 unsigned int trace_ctx; 186 u64 *calltime; 187 int ret; 188 189 if (ftrace_graph_ignore_func(gops, trace)) 190 return 0; 191 /* 192 * Do not trace a function if it's filtered by set_graph_notrace. 193 * Make the index of ret stack negative to indicate that it should 194 * ignore further functions. But it needs its own ret stack entry 195 * to recover the original index in order to continue tracing after 196 * returning from the function. 197 */ 198 if (ftrace_graph_notrace_addr(trace->func)) 199 return 1; 200 201 if (!func_prolog_dec(tr, &data, &flags)) 202 return 0; 203 204 calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime)); 205 if (!calltime) 206 return 0; 207 208 *calltime = trace_clock_local(); 209 210 trace_ctx = tracing_gen_ctx_flags(flags); 211 ret = __trace_graph_entry(tr, trace, trace_ctx); 212 local_dec(&data->disabled); 213 214 return ret; 215 } 216 217 static void irqsoff_graph_return(struct ftrace_graph_ret *trace, 218 struct fgraph_ops *gops, 219 struct ftrace_regs *fregs) 220 { 221 struct trace_array *tr = irqsoff_trace; 222 struct trace_array_cpu *data; 223 unsigned long flags; 224 unsigned int trace_ctx; 225 u64 *calltime; 226 u64 rettime; 227 int size; 228 229 ftrace_graph_addr_finish(gops, trace); 230 231 if (!func_prolog_dec(tr, &data, &flags)) 232 return; 233 234 rettime = trace_clock_local(); 235 calltime = fgraph_retrieve_data(gops->idx, &size); 236 if (!calltime) 237 return; 238 239 trace_ctx = tracing_gen_ctx_flags(flags); 240 __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); 241 local_dec(&data->disabled); 242 } 243 244 static struct fgraph_ops fgraph_ops = { 245 .entryfunc = &irqsoff_graph_entry, 246 .retfunc = &irqsoff_graph_return, 247 }; 248 249 static void irqsoff_trace_open(struct trace_iterator *iter) 250 { 251 if (is_graph(iter->tr)) 252 graph_trace_open(iter); 253 } 254 255 static void irqsoff_trace_close(struct trace_iterator *iter) 256 { 257 if (iter->private) 258 graph_trace_close(iter); 259 } 260 261 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \ 262 TRACE_GRAPH_PRINT_PROC | \ 263 TRACE_GRAPH_PRINT_REL_TIME | \ 264 TRACE_GRAPH_PRINT_DURATION) 265 266 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 267 { 268 /* 269 * In graph mode call the graph tracer output function, 270 * otherwise go with the TRACE_FN event handler 271 */ 272 if (is_graph(iter->tr)) 273 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); 274 275 return TRACE_TYPE_UNHANDLED; 276 } 277 278 static void irqsoff_print_header(struct seq_file *s) 279 { 280 struct trace_array *tr = irqsoff_trace; 281 282 if (is_graph(tr)) 283 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); 284 else 285 trace_default_header(s); 286 } 287 288 static void 289 __trace_function(struct trace_array *tr, 290 unsigned long ip, unsigned long parent_ip, 291 unsigned int trace_ctx) 292 { 293 if (is_graph(tr)) 294 trace_graph_function(tr, ip, parent_ip, trace_ctx); 295 else 296 trace_function(tr, ip, parent_ip, trace_ctx, NULL); 297 } 298 299 #else 300 static inline void 301 __trace_function(struct trace_array *tr, 302 unsigned long ip, unsigned long parent_ip, 303 unsigned int trace_ctx) 304 { 305 return trace_function(tr, ip, parent_ip, trace_ctx, NULL); 306 } 307 308 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 309 { 310 return TRACE_TYPE_UNHANDLED; 311 } 312 313 static void irqsoff_trace_open(struct trace_iterator *iter) { } 314 static void irqsoff_trace_close(struct trace_iterator *iter) { } 315 316 #ifdef CONFIG_FUNCTION_TRACER 317 static void irqsoff_print_header(struct seq_file *s) 318 { 319 trace_default_header(s); 320 } 321 #else 322 static void irqsoff_print_header(struct seq_file *s) 323 { 324 trace_latency_header(s); 325 } 326 #endif /* CONFIG_FUNCTION_TRACER */ 327 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 328 329 /* 330 * Should this new latency be reported/recorded? 331 */ 332 static bool report_latency(struct trace_array *tr, u64 delta) 333 { 334 if (tracing_thresh) { 335 if (delta < tracing_thresh) 336 return false; 337 } else { 338 if (delta <= tr->max_latency) 339 return false; 340 } 341 return true; 342 } 343 344 static void 345 check_critical_timing(struct trace_array *tr, 346 struct trace_array_cpu *data, 347 unsigned long parent_ip, 348 int cpu) 349 { 350 u64 T0, T1, delta; 351 unsigned long flags; 352 unsigned int trace_ctx; 353 354 T0 = data->preempt_timestamp; 355 T1 = ftrace_now(cpu); 356 delta = T1-T0; 357 358 trace_ctx = tracing_gen_ctx(); 359 360 if (!report_latency(tr, delta)) 361 goto out; 362 363 raw_spin_lock_irqsave(&max_trace_lock, flags); 364 365 /* check if we are still the max latency */ 366 if (!report_latency(tr, delta)) 367 goto out_unlock; 368 369 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 370 /* Skip 5 functions to get to the irq/preempt enable function */ 371 __trace_stack(tr, trace_ctx, 5); 372 373 if (data->critical_sequence != max_sequence) 374 goto out_unlock; 375 376 data->critical_end = parent_ip; 377 378 if (likely(!is_tracing_stopped())) { 379 tr->max_latency = delta; 380 update_max_tr_single(tr, current, cpu); 381 } 382 383 max_sequence++; 384 385 out_unlock: 386 raw_spin_unlock_irqrestore(&max_trace_lock, flags); 387 388 out: 389 data->critical_sequence = max_sequence; 390 data->preempt_timestamp = ftrace_now(cpu); 391 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 392 } 393 394 static nokprobe_inline void 395 start_critical_timing(unsigned long ip, unsigned long parent_ip) 396 { 397 int cpu; 398 struct trace_array *tr = irqsoff_trace; 399 struct trace_array_cpu *data; 400 long disabled; 401 402 if (!tracer_enabled || !tracing_is_enabled()) 403 return; 404 405 cpu = raw_smp_processor_id(); 406 407 if (per_cpu(tracing_cpu, cpu)) 408 return; 409 410 data = per_cpu_ptr(tr->array_buffer.data, cpu); 411 412 if (unlikely(!data) || local_read(&data->disabled)) 413 return; 414 415 disabled = local_inc_return(&data->disabled); 416 417 if (disabled == 1) { 418 data->critical_sequence = max_sequence; 419 data->preempt_timestamp = ftrace_now(cpu); 420 data->critical_start = parent_ip ? : ip; 421 422 __trace_function(tr, ip, parent_ip, tracing_gen_ctx()); 423 424 per_cpu(tracing_cpu, cpu) = 1; 425 } 426 427 local_dec(&data->disabled); 428 } 429 430 static nokprobe_inline void 431 stop_critical_timing(unsigned long ip, unsigned long parent_ip) 432 { 433 int cpu; 434 struct trace_array *tr = irqsoff_trace; 435 struct trace_array_cpu *data; 436 unsigned int trace_ctx; 437 long disabled; 438 439 cpu = raw_smp_processor_id(); 440 /* Always clear the tracing cpu on stopping the trace */ 441 if (unlikely(per_cpu(tracing_cpu, cpu))) 442 per_cpu(tracing_cpu, cpu) = 0; 443 else 444 return; 445 446 if (!tracer_enabled || !tracing_is_enabled()) 447 return; 448 449 data = per_cpu_ptr(tr->array_buffer.data, cpu); 450 451 if (unlikely(!data) || 452 !data->critical_start || local_read(&data->disabled)) 453 return; 454 455 disabled = local_inc_return(&data->disabled); 456 457 if (disabled == 1) { 458 trace_ctx = tracing_gen_ctx(); 459 __trace_function(tr, ip, parent_ip, trace_ctx); 460 check_critical_timing(tr, data, parent_ip ? : ip, cpu); 461 data->critical_start = 0; 462 } 463 464 local_dec(&data->disabled); 465 } 466 467 /* start and stop critical timings used to for stoppage (in idle) */ 468 void start_critical_timings(void) 469 { 470 if (preempt_trace(preempt_count()) || irq_trace()) 471 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 472 } 473 EXPORT_SYMBOL_GPL(start_critical_timings); 474 NOKPROBE_SYMBOL(start_critical_timings); 475 476 void stop_critical_timings(void) 477 { 478 if (preempt_trace(preempt_count()) || irq_trace()) 479 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 480 } 481 EXPORT_SYMBOL_GPL(stop_critical_timings); 482 NOKPROBE_SYMBOL(stop_critical_timings); 483 484 #ifdef CONFIG_FUNCTION_TRACER 485 static bool function_enabled; 486 487 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 488 { 489 int ret; 490 491 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ 492 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION))) 493 return 0; 494 495 if (graph) 496 ret = register_ftrace_graph(&fgraph_ops); 497 else 498 ret = register_ftrace_function(tr->ops); 499 500 if (!ret) 501 function_enabled = true; 502 503 return ret; 504 } 505 506 static void unregister_irqsoff_function(struct trace_array *tr, int graph) 507 { 508 if (!function_enabled) 509 return; 510 511 if (graph) 512 unregister_ftrace_graph(&fgraph_ops); 513 else 514 unregister_ftrace_function(tr->ops); 515 516 function_enabled = false; 517 } 518 519 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 520 { 521 if (!(mask & TRACE_ITER_FUNCTION)) 522 return 0; 523 524 if (set) 525 register_irqsoff_function(tr, is_graph(tr), 1); 526 else 527 unregister_irqsoff_function(tr, is_graph(tr)); 528 return 1; 529 } 530 #else 531 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 532 { 533 return 0; 534 } 535 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { } 536 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 537 { 538 return 0; 539 } 540 #endif /* CONFIG_FUNCTION_TRACER */ 541 542 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) 543 { 544 struct tracer *tracer = tr->current_trace; 545 546 if (irqsoff_function_set(tr, mask, set)) 547 return 0; 548 549 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 550 if (mask & TRACE_ITER_DISPLAY_GRAPH) 551 return irqsoff_display_graph(tr, set); 552 #endif 553 554 return trace_keep_overwrite(tracer, mask, set); 555 } 556 557 static int start_irqsoff_tracer(struct trace_array *tr, int graph) 558 { 559 int ret; 560 561 ret = register_irqsoff_function(tr, graph, 0); 562 563 if (!ret && tracing_is_enabled()) 564 tracer_enabled = 1; 565 else 566 tracer_enabled = 0; 567 568 return ret; 569 } 570 571 static void stop_irqsoff_tracer(struct trace_array *tr, int graph) 572 { 573 tracer_enabled = 0; 574 575 unregister_irqsoff_function(tr, graph); 576 } 577 578 static bool irqsoff_busy; 579 580 static int __irqsoff_tracer_init(struct trace_array *tr) 581 { 582 if (irqsoff_busy) 583 return -EBUSY; 584 585 save_flags = tr->trace_flags; 586 587 /* non overwrite screws up the latency tracers */ 588 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); 589 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); 590 /* without pause, we will produce garbage if another latency occurs */ 591 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1); 592 593 tr->max_latency = 0; 594 irqsoff_trace = tr; 595 /* make sure that the tracer is visible */ 596 smp_wmb(); 597 598 ftrace_init_array_ops(tr, irqsoff_tracer_call); 599 600 /* Only toplevel instance supports graph tracing */ 601 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && 602 is_graph(tr)))) 603 printk(KERN_ERR "failed to start irqsoff tracer\n"); 604 605 irqsoff_busy = true; 606 return 0; 607 } 608 609 static void __irqsoff_tracer_reset(struct trace_array *tr) 610 { 611 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; 612 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; 613 int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE; 614 615 stop_irqsoff_tracer(tr, is_graph(tr)); 616 617 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); 618 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); 619 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag); 620 ftrace_reset_array_ops(tr); 621 622 irqsoff_busy = false; 623 } 624 625 static void irqsoff_tracer_start(struct trace_array *tr) 626 { 627 tracer_enabled = 1; 628 } 629 630 static void irqsoff_tracer_stop(struct trace_array *tr) 631 { 632 tracer_enabled = 0; 633 } 634 635 #ifdef CONFIG_IRQSOFF_TRACER 636 /* 637 * We are only interested in hardirq on/off events: 638 */ 639 void tracer_hardirqs_on(unsigned long a0, unsigned long a1) 640 { 641 if (!preempt_trace(preempt_count()) && irq_trace()) 642 stop_critical_timing(a0, a1); 643 } 644 NOKPROBE_SYMBOL(tracer_hardirqs_on); 645 646 void tracer_hardirqs_off(unsigned long a0, unsigned long a1) 647 { 648 if (!preempt_trace(preempt_count()) && irq_trace()) 649 start_critical_timing(a0, a1); 650 } 651 NOKPROBE_SYMBOL(tracer_hardirqs_off); 652 653 static int irqsoff_tracer_init(struct trace_array *tr) 654 { 655 trace_type = TRACER_IRQS_OFF; 656 657 return __irqsoff_tracer_init(tr); 658 } 659 660 static void irqsoff_tracer_reset(struct trace_array *tr) 661 { 662 __irqsoff_tracer_reset(tr); 663 } 664 665 static struct tracer irqsoff_tracer __read_mostly = 666 { 667 .name = "irqsoff", 668 .init = irqsoff_tracer_init, 669 .reset = irqsoff_tracer_reset, 670 .start = irqsoff_tracer_start, 671 .stop = irqsoff_tracer_stop, 672 .print_max = true, 673 .print_header = irqsoff_print_header, 674 .print_line = irqsoff_print_line, 675 .flag_changed = irqsoff_flag_changed, 676 #ifdef CONFIG_FTRACE_SELFTEST 677 .selftest = trace_selftest_startup_irqsoff, 678 #endif 679 .open = irqsoff_trace_open, 680 .close = irqsoff_trace_close, 681 .allow_instances = true, 682 .use_max_tr = true, 683 }; 684 #endif /* CONFIG_IRQSOFF_TRACER */ 685 686 #ifdef CONFIG_PREEMPT_TRACER 687 void tracer_preempt_on(unsigned long a0, unsigned long a1) 688 { 689 if (preempt_trace(preempt_count()) && !irq_trace()) 690 stop_critical_timing(a0, a1); 691 } 692 693 void tracer_preempt_off(unsigned long a0, unsigned long a1) 694 { 695 if (preempt_trace(preempt_count()) && !irq_trace()) 696 start_critical_timing(a0, a1); 697 } 698 699 static int preemptoff_tracer_init(struct trace_array *tr) 700 { 701 trace_type = TRACER_PREEMPT_OFF; 702 703 return __irqsoff_tracer_init(tr); 704 } 705 706 static void preemptoff_tracer_reset(struct trace_array *tr) 707 { 708 __irqsoff_tracer_reset(tr); 709 } 710 711 static struct tracer preemptoff_tracer __read_mostly = 712 { 713 .name = "preemptoff", 714 .init = preemptoff_tracer_init, 715 .reset = preemptoff_tracer_reset, 716 .start = irqsoff_tracer_start, 717 .stop = irqsoff_tracer_stop, 718 .print_max = true, 719 .print_header = irqsoff_print_header, 720 .print_line = irqsoff_print_line, 721 .flag_changed = irqsoff_flag_changed, 722 #ifdef CONFIG_FTRACE_SELFTEST 723 .selftest = trace_selftest_startup_preemptoff, 724 #endif 725 .open = irqsoff_trace_open, 726 .close = irqsoff_trace_close, 727 .allow_instances = true, 728 .use_max_tr = true, 729 }; 730 #endif /* CONFIG_PREEMPT_TRACER */ 731 732 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 733 734 static int preemptirqsoff_tracer_init(struct trace_array *tr) 735 { 736 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; 737 738 return __irqsoff_tracer_init(tr); 739 } 740 741 static void preemptirqsoff_tracer_reset(struct trace_array *tr) 742 { 743 __irqsoff_tracer_reset(tr); 744 } 745 746 static struct tracer preemptirqsoff_tracer __read_mostly = 747 { 748 .name = "preemptirqsoff", 749 .init = preemptirqsoff_tracer_init, 750 .reset = preemptirqsoff_tracer_reset, 751 .start = irqsoff_tracer_start, 752 .stop = irqsoff_tracer_stop, 753 .print_max = true, 754 .print_header = irqsoff_print_header, 755 .print_line = irqsoff_print_line, 756 .flag_changed = irqsoff_flag_changed, 757 #ifdef CONFIG_FTRACE_SELFTEST 758 .selftest = trace_selftest_startup_preemptirqsoff, 759 #endif 760 .open = irqsoff_trace_open, 761 .close = irqsoff_trace_close, 762 .allow_instances = true, 763 .use_max_tr = true, 764 }; 765 #endif 766 767 __init static int init_irqsoff_tracer(void) 768 { 769 #ifdef CONFIG_IRQSOFF_TRACER 770 register_tracer(&irqsoff_tracer); 771 #endif 772 #ifdef CONFIG_PREEMPT_TRACER 773 register_tracer(&preemptoff_tracer); 774 #endif 775 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 776 register_tracer(&preemptirqsoff_tracer); 777 #endif 778 779 return 0; 780 } 781 core_initcall(init_irqsoff_tracer); 782 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */ 783