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 = atomic_inc_return(&(*data)->disabled); 127 128 if (likely(disabled == 1)) 129 return 1; 130 131 atomic_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); 154 155 atomic_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 { 181 struct trace_array *tr = irqsoff_trace; 182 struct trace_array_cpu *data; 183 unsigned long flags; 184 unsigned int trace_ctx; 185 int ret; 186 187 if (ftrace_graph_ignore_func(gops, trace)) 188 return 0; 189 /* 190 * Do not trace a function if it's filtered by set_graph_notrace. 191 * Make the index of ret stack negative to indicate that it should 192 * ignore further functions. But it needs its own ret stack entry 193 * to recover the original index in order to continue tracing after 194 * returning from the function. 195 */ 196 if (ftrace_graph_notrace_addr(trace->func)) 197 return 1; 198 199 if (!func_prolog_dec(tr, &data, &flags)) 200 return 0; 201 202 trace_ctx = tracing_gen_ctx_flags(flags); 203 ret = __trace_graph_entry(tr, trace, trace_ctx); 204 atomic_dec(&data->disabled); 205 206 return ret; 207 } 208 209 static void irqsoff_graph_return(struct ftrace_graph_ret *trace, 210 struct fgraph_ops *gops) 211 { 212 struct trace_array *tr = irqsoff_trace; 213 struct trace_array_cpu *data; 214 unsigned long flags; 215 unsigned int trace_ctx; 216 217 ftrace_graph_addr_finish(gops, trace); 218 219 if (!func_prolog_dec(tr, &data, &flags)) 220 return; 221 222 trace_ctx = tracing_gen_ctx_flags(flags); 223 __trace_graph_return(tr, trace, trace_ctx); 224 atomic_dec(&data->disabled); 225 } 226 227 static struct fgraph_ops fgraph_ops = { 228 .entryfunc = &irqsoff_graph_entry, 229 .retfunc = &irqsoff_graph_return, 230 }; 231 232 static void irqsoff_trace_open(struct trace_iterator *iter) 233 { 234 if (is_graph(iter->tr)) 235 graph_trace_open(iter); 236 else 237 iter->private = NULL; 238 } 239 240 static void irqsoff_trace_close(struct trace_iterator *iter) 241 { 242 if (iter->private) 243 graph_trace_close(iter); 244 } 245 246 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \ 247 TRACE_GRAPH_PRINT_PROC | \ 248 TRACE_GRAPH_PRINT_REL_TIME | \ 249 TRACE_GRAPH_PRINT_DURATION) 250 251 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 252 { 253 /* 254 * In graph mode call the graph tracer output function, 255 * otherwise go with the TRACE_FN event handler 256 */ 257 if (is_graph(iter->tr)) 258 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); 259 260 return TRACE_TYPE_UNHANDLED; 261 } 262 263 static void irqsoff_print_header(struct seq_file *s) 264 { 265 struct trace_array *tr = irqsoff_trace; 266 267 if (is_graph(tr)) 268 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); 269 else 270 trace_default_header(s); 271 } 272 273 static void 274 __trace_function(struct trace_array *tr, 275 unsigned long ip, unsigned long parent_ip, 276 unsigned int trace_ctx) 277 { 278 if (is_graph(tr)) 279 trace_graph_function(tr, ip, parent_ip, trace_ctx); 280 else 281 trace_function(tr, ip, parent_ip, trace_ctx); 282 } 283 284 #else 285 #define __trace_function trace_function 286 287 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 288 { 289 return TRACE_TYPE_UNHANDLED; 290 } 291 292 static void irqsoff_trace_open(struct trace_iterator *iter) { } 293 static void irqsoff_trace_close(struct trace_iterator *iter) { } 294 295 #ifdef CONFIG_FUNCTION_TRACER 296 static void irqsoff_print_header(struct seq_file *s) 297 { 298 trace_default_header(s); 299 } 300 #else 301 static void irqsoff_print_header(struct seq_file *s) 302 { 303 trace_latency_header(s); 304 } 305 #endif /* CONFIG_FUNCTION_TRACER */ 306 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 307 308 /* 309 * Should this new latency be reported/recorded? 310 */ 311 static bool report_latency(struct trace_array *tr, u64 delta) 312 { 313 if (tracing_thresh) { 314 if (delta < tracing_thresh) 315 return false; 316 } else { 317 if (delta <= tr->max_latency) 318 return false; 319 } 320 return true; 321 } 322 323 static void 324 check_critical_timing(struct trace_array *tr, 325 struct trace_array_cpu *data, 326 unsigned long parent_ip, 327 int cpu) 328 { 329 u64 T0, T1, delta; 330 unsigned long flags; 331 unsigned int trace_ctx; 332 333 T0 = data->preempt_timestamp; 334 T1 = ftrace_now(cpu); 335 delta = T1-T0; 336 337 trace_ctx = tracing_gen_ctx(); 338 339 if (!report_latency(tr, delta)) 340 goto out; 341 342 raw_spin_lock_irqsave(&max_trace_lock, flags); 343 344 /* check if we are still the max latency */ 345 if (!report_latency(tr, delta)) 346 goto out_unlock; 347 348 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 349 /* Skip 5 functions to get to the irq/preempt enable function */ 350 __trace_stack(tr, trace_ctx, 5); 351 352 if (data->critical_sequence != max_sequence) 353 goto out_unlock; 354 355 data->critical_end = parent_ip; 356 357 if (likely(!is_tracing_stopped())) { 358 tr->max_latency = delta; 359 update_max_tr_single(tr, current, cpu); 360 } 361 362 max_sequence++; 363 364 out_unlock: 365 raw_spin_unlock_irqrestore(&max_trace_lock, flags); 366 367 out: 368 data->critical_sequence = max_sequence; 369 data->preempt_timestamp = ftrace_now(cpu); 370 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 371 } 372 373 static nokprobe_inline void 374 start_critical_timing(unsigned long ip, unsigned long parent_ip) 375 { 376 int cpu; 377 struct trace_array *tr = irqsoff_trace; 378 struct trace_array_cpu *data; 379 380 if (!tracer_enabled || !tracing_is_enabled()) 381 return; 382 383 cpu = raw_smp_processor_id(); 384 385 if (per_cpu(tracing_cpu, cpu)) 386 return; 387 388 data = per_cpu_ptr(tr->array_buffer.data, cpu); 389 390 if (unlikely(!data) || atomic_read(&data->disabled)) 391 return; 392 393 atomic_inc(&data->disabled); 394 395 data->critical_sequence = max_sequence; 396 data->preempt_timestamp = ftrace_now(cpu); 397 data->critical_start = parent_ip ? : ip; 398 399 __trace_function(tr, ip, parent_ip, tracing_gen_ctx()); 400 401 per_cpu(tracing_cpu, cpu) = 1; 402 403 atomic_dec(&data->disabled); 404 } 405 406 static nokprobe_inline void 407 stop_critical_timing(unsigned long ip, unsigned long parent_ip) 408 { 409 int cpu; 410 struct trace_array *tr = irqsoff_trace; 411 struct trace_array_cpu *data; 412 unsigned int trace_ctx; 413 414 cpu = raw_smp_processor_id(); 415 /* Always clear the tracing cpu on stopping the trace */ 416 if (unlikely(per_cpu(tracing_cpu, cpu))) 417 per_cpu(tracing_cpu, cpu) = 0; 418 else 419 return; 420 421 if (!tracer_enabled || !tracing_is_enabled()) 422 return; 423 424 data = per_cpu_ptr(tr->array_buffer.data, cpu); 425 426 if (unlikely(!data) || 427 !data->critical_start || atomic_read(&data->disabled)) 428 return; 429 430 atomic_inc(&data->disabled); 431 432 trace_ctx = tracing_gen_ctx(); 433 __trace_function(tr, ip, parent_ip, trace_ctx); 434 check_critical_timing(tr, data, parent_ip ? : ip, cpu); 435 data->critical_start = 0; 436 atomic_dec(&data->disabled); 437 } 438 439 /* start and stop critical timings used to for stoppage (in idle) */ 440 void start_critical_timings(void) 441 { 442 if (preempt_trace(preempt_count()) || irq_trace()) 443 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 444 } 445 EXPORT_SYMBOL_GPL(start_critical_timings); 446 NOKPROBE_SYMBOL(start_critical_timings); 447 448 void stop_critical_timings(void) 449 { 450 if (preempt_trace(preempt_count()) || irq_trace()) 451 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 452 } 453 EXPORT_SYMBOL_GPL(stop_critical_timings); 454 NOKPROBE_SYMBOL(stop_critical_timings); 455 456 #ifdef CONFIG_FUNCTION_TRACER 457 static bool function_enabled; 458 459 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 460 { 461 int ret; 462 463 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ 464 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION))) 465 return 0; 466 467 if (graph) 468 ret = register_ftrace_graph(&fgraph_ops); 469 else 470 ret = register_ftrace_function(tr->ops); 471 472 if (!ret) 473 function_enabled = true; 474 475 return ret; 476 } 477 478 static void unregister_irqsoff_function(struct trace_array *tr, int graph) 479 { 480 if (!function_enabled) 481 return; 482 483 if (graph) 484 unregister_ftrace_graph(&fgraph_ops); 485 else 486 unregister_ftrace_function(tr->ops); 487 488 function_enabled = false; 489 } 490 491 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 492 { 493 if (!(mask & TRACE_ITER_FUNCTION)) 494 return 0; 495 496 if (set) 497 register_irqsoff_function(tr, is_graph(tr), 1); 498 else 499 unregister_irqsoff_function(tr, is_graph(tr)); 500 return 1; 501 } 502 #else 503 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 504 { 505 return 0; 506 } 507 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { } 508 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 509 { 510 return 0; 511 } 512 #endif /* CONFIG_FUNCTION_TRACER */ 513 514 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) 515 { 516 struct tracer *tracer = tr->current_trace; 517 518 if (irqsoff_function_set(tr, mask, set)) 519 return 0; 520 521 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 522 if (mask & TRACE_ITER_DISPLAY_GRAPH) 523 return irqsoff_display_graph(tr, set); 524 #endif 525 526 return trace_keep_overwrite(tracer, mask, set); 527 } 528 529 static int start_irqsoff_tracer(struct trace_array *tr, int graph) 530 { 531 int ret; 532 533 ret = register_irqsoff_function(tr, graph, 0); 534 535 if (!ret && tracing_is_enabled()) 536 tracer_enabled = 1; 537 else 538 tracer_enabled = 0; 539 540 return ret; 541 } 542 543 static void stop_irqsoff_tracer(struct trace_array *tr, int graph) 544 { 545 tracer_enabled = 0; 546 547 unregister_irqsoff_function(tr, graph); 548 } 549 550 static bool irqsoff_busy; 551 552 static int __irqsoff_tracer_init(struct trace_array *tr) 553 { 554 if (irqsoff_busy) 555 return -EBUSY; 556 557 save_flags = tr->trace_flags; 558 559 /* non overwrite screws up the latency tracers */ 560 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); 561 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); 562 /* without pause, we will produce garbage if another latency occurs */ 563 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1); 564 565 tr->max_latency = 0; 566 irqsoff_trace = tr; 567 /* make sure that the tracer is visible */ 568 smp_wmb(); 569 570 ftrace_init_array_ops(tr, irqsoff_tracer_call); 571 572 /* Only toplevel instance supports graph tracing */ 573 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && 574 is_graph(tr)))) 575 printk(KERN_ERR "failed to start irqsoff tracer\n"); 576 577 irqsoff_busy = true; 578 return 0; 579 } 580 581 static void __irqsoff_tracer_reset(struct trace_array *tr) 582 { 583 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; 584 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; 585 int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE; 586 587 stop_irqsoff_tracer(tr, is_graph(tr)); 588 589 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); 590 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); 591 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag); 592 ftrace_reset_array_ops(tr); 593 594 irqsoff_busy = false; 595 } 596 597 static void irqsoff_tracer_start(struct trace_array *tr) 598 { 599 tracer_enabled = 1; 600 } 601 602 static void irqsoff_tracer_stop(struct trace_array *tr) 603 { 604 tracer_enabled = 0; 605 } 606 607 #ifdef CONFIG_IRQSOFF_TRACER 608 /* 609 * We are only interested in hardirq on/off events: 610 */ 611 void tracer_hardirqs_on(unsigned long a0, unsigned long a1) 612 { 613 if (!preempt_trace(preempt_count()) && irq_trace()) 614 stop_critical_timing(a0, a1); 615 } 616 NOKPROBE_SYMBOL(tracer_hardirqs_on); 617 618 void tracer_hardirqs_off(unsigned long a0, unsigned long a1) 619 { 620 if (!preempt_trace(preempt_count()) && irq_trace()) 621 start_critical_timing(a0, a1); 622 } 623 NOKPROBE_SYMBOL(tracer_hardirqs_off); 624 625 static int irqsoff_tracer_init(struct trace_array *tr) 626 { 627 trace_type = TRACER_IRQS_OFF; 628 629 return __irqsoff_tracer_init(tr); 630 } 631 632 static void irqsoff_tracer_reset(struct trace_array *tr) 633 { 634 __irqsoff_tracer_reset(tr); 635 } 636 637 static struct tracer irqsoff_tracer __read_mostly = 638 { 639 .name = "irqsoff", 640 .init = irqsoff_tracer_init, 641 .reset = irqsoff_tracer_reset, 642 .start = irqsoff_tracer_start, 643 .stop = irqsoff_tracer_stop, 644 .print_max = true, 645 .print_header = irqsoff_print_header, 646 .print_line = irqsoff_print_line, 647 .flag_changed = irqsoff_flag_changed, 648 #ifdef CONFIG_FTRACE_SELFTEST 649 .selftest = trace_selftest_startup_irqsoff, 650 #endif 651 .open = irqsoff_trace_open, 652 .close = irqsoff_trace_close, 653 .allow_instances = true, 654 .use_max_tr = true, 655 }; 656 #endif /* CONFIG_IRQSOFF_TRACER */ 657 658 #ifdef CONFIG_PREEMPT_TRACER 659 void tracer_preempt_on(unsigned long a0, unsigned long a1) 660 { 661 if (preempt_trace(preempt_count()) && !irq_trace()) 662 stop_critical_timing(a0, a1); 663 } 664 665 void tracer_preempt_off(unsigned long a0, unsigned long a1) 666 { 667 if (preempt_trace(preempt_count()) && !irq_trace()) 668 start_critical_timing(a0, a1); 669 } 670 671 static int preemptoff_tracer_init(struct trace_array *tr) 672 { 673 trace_type = TRACER_PREEMPT_OFF; 674 675 return __irqsoff_tracer_init(tr); 676 } 677 678 static void preemptoff_tracer_reset(struct trace_array *tr) 679 { 680 __irqsoff_tracer_reset(tr); 681 } 682 683 static struct tracer preemptoff_tracer __read_mostly = 684 { 685 .name = "preemptoff", 686 .init = preemptoff_tracer_init, 687 .reset = preemptoff_tracer_reset, 688 .start = irqsoff_tracer_start, 689 .stop = irqsoff_tracer_stop, 690 .print_max = true, 691 .print_header = irqsoff_print_header, 692 .print_line = irqsoff_print_line, 693 .flag_changed = irqsoff_flag_changed, 694 #ifdef CONFIG_FTRACE_SELFTEST 695 .selftest = trace_selftest_startup_preemptoff, 696 #endif 697 .open = irqsoff_trace_open, 698 .close = irqsoff_trace_close, 699 .allow_instances = true, 700 .use_max_tr = true, 701 }; 702 #endif /* CONFIG_PREEMPT_TRACER */ 703 704 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 705 706 static int preemptirqsoff_tracer_init(struct trace_array *tr) 707 { 708 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; 709 710 return __irqsoff_tracer_init(tr); 711 } 712 713 static void preemptirqsoff_tracer_reset(struct trace_array *tr) 714 { 715 __irqsoff_tracer_reset(tr); 716 } 717 718 static struct tracer preemptirqsoff_tracer __read_mostly = 719 { 720 .name = "preemptirqsoff", 721 .init = preemptirqsoff_tracer_init, 722 .reset = preemptirqsoff_tracer_reset, 723 .start = irqsoff_tracer_start, 724 .stop = irqsoff_tracer_stop, 725 .print_max = true, 726 .print_header = irqsoff_print_header, 727 .print_line = irqsoff_print_line, 728 .flag_changed = irqsoff_flag_changed, 729 #ifdef CONFIG_FTRACE_SELFTEST 730 .selftest = trace_selftest_startup_preemptirqsoff, 731 #endif 732 .open = irqsoff_trace_open, 733 .close = irqsoff_trace_close, 734 .allow_instances = true, 735 .use_max_tr = true, 736 }; 737 #endif 738 739 __init static int init_irqsoff_tracer(void) 740 { 741 #ifdef CONFIG_IRQSOFF_TRACER 742 register_tracer(&irqsoff_tracer); 743 #endif 744 #ifdef CONFIG_PREEMPT_TRACER 745 register_tracer(&preemptoff_tracer); 746 #endif 747 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 748 register_tracer(&preemptirqsoff_tracer); 749 #endif 750 751 return 0; 752 } 753 core_initcall(init_irqsoff_tracer); 754 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */ 755