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 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 atomic_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 atomic_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 else 254 iter->private = NULL; 255 } 256 257 static void irqsoff_trace_close(struct trace_iterator *iter) 258 { 259 if (iter->private) 260 graph_trace_close(iter); 261 } 262 263 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \ 264 TRACE_GRAPH_PRINT_PROC | \ 265 TRACE_GRAPH_PRINT_REL_TIME | \ 266 TRACE_GRAPH_PRINT_DURATION) 267 268 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 269 { 270 /* 271 * In graph mode call the graph tracer output function, 272 * otherwise go with the TRACE_FN event handler 273 */ 274 if (is_graph(iter->tr)) 275 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); 276 277 return TRACE_TYPE_UNHANDLED; 278 } 279 280 static void irqsoff_print_header(struct seq_file *s) 281 { 282 struct trace_array *tr = irqsoff_trace; 283 284 if (is_graph(tr)) 285 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); 286 else 287 trace_default_header(s); 288 } 289 290 static void 291 __trace_function(struct trace_array *tr, 292 unsigned long ip, unsigned long parent_ip, 293 unsigned int trace_ctx) 294 { 295 if (is_graph(tr)) 296 trace_graph_function(tr, ip, parent_ip, trace_ctx); 297 else 298 trace_function(tr, ip, parent_ip, trace_ctx); 299 } 300 301 #else 302 #define __trace_function trace_function 303 304 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 305 { 306 return TRACE_TYPE_UNHANDLED; 307 } 308 309 static void irqsoff_trace_open(struct trace_iterator *iter) { } 310 static void irqsoff_trace_close(struct trace_iterator *iter) { } 311 312 #ifdef CONFIG_FUNCTION_TRACER 313 static void irqsoff_print_header(struct seq_file *s) 314 { 315 trace_default_header(s); 316 } 317 #else 318 static void irqsoff_print_header(struct seq_file *s) 319 { 320 trace_latency_header(s); 321 } 322 #endif /* CONFIG_FUNCTION_TRACER */ 323 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 324 325 /* 326 * Should this new latency be reported/recorded? 327 */ 328 static bool report_latency(struct trace_array *tr, u64 delta) 329 { 330 if (tracing_thresh) { 331 if (delta < tracing_thresh) 332 return false; 333 } else { 334 if (delta <= tr->max_latency) 335 return false; 336 } 337 return true; 338 } 339 340 static void 341 check_critical_timing(struct trace_array *tr, 342 struct trace_array_cpu *data, 343 unsigned long parent_ip, 344 int cpu) 345 { 346 u64 T0, T1, delta; 347 unsigned long flags; 348 unsigned int trace_ctx; 349 350 T0 = data->preempt_timestamp; 351 T1 = ftrace_now(cpu); 352 delta = T1-T0; 353 354 trace_ctx = tracing_gen_ctx(); 355 356 if (!report_latency(tr, delta)) 357 goto out; 358 359 raw_spin_lock_irqsave(&max_trace_lock, flags); 360 361 /* check if we are still the max latency */ 362 if (!report_latency(tr, delta)) 363 goto out_unlock; 364 365 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 366 /* Skip 5 functions to get to the irq/preempt enable function */ 367 __trace_stack(tr, trace_ctx, 5); 368 369 if (data->critical_sequence != max_sequence) 370 goto out_unlock; 371 372 data->critical_end = parent_ip; 373 374 if (likely(!is_tracing_stopped())) { 375 tr->max_latency = delta; 376 update_max_tr_single(tr, current, cpu); 377 } 378 379 max_sequence++; 380 381 out_unlock: 382 raw_spin_unlock_irqrestore(&max_trace_lock, flags); 383 384 out: 385 data->critical_sequence = max_sequence; 386 data->preempt_timestamp = ftrace_now(cpu); 387 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 388 } 389 390 static nokprobe_inline void 391 start_critical_timing(unsigned long ip, unsigned long parent_ip) 392 { 393 int cpu; 394 struct trace_array *tr = irqsoff_trace; 395 struct trace_array_cpu *data; 396 397 if (!tracer_enabled || !tracing_is_enabled()) 398 return; 399 400 cpu = raw_smp_processor_id(); 401 402 if (per_cpu(tracing_cpu, cpu)) 403 return; 404 405 data = per_cpu_ptr(tr->array_buffer.data, cpu); 406 407 if (unlikely(!data) || atomic_read(&data->disabled)) 408 return; 409 410 atomic_inc(&data->disabled); 411 412 data->critical_sequence = max_sequence; 413 data->preempt_timestamp = ftrace_now(cpu); 414 data->critical_start = parent_ip ? : ip; 415 416 __trace_function(tr, ip, parent_ip, tracing_gen_ctx()); 417 418 per_cpu(tracing_cpu, cpu) = 1; 419 420 atomic_dec(&data->disabled); 421 } 422 423 static nokprobe_inline void 424 stop_critical_timing(unsigned long ip, unsigned long parent_ip) 425 { 426 int cpu; 427 struct trace_array *tr = irqsoff_trace; 428 struct trace_array_cpu *data; 429 unsigned int trace_ctx; 430 431 cpu = raw_smp_processor_id(); 432 /* Always clear the tracing cpu on stopping the trace */ 433 if (unlikely(per_cpu(tracing_cpu, cpu))) 434 per_cpu(tracing_cpu, cpu) = 0; 435 else 436 return; 437 438 if (!tracer_enabled || !tracing_is_enabled()) 439 return; 440 441 data = per_cpu_ptr(tr->array_buffer.data, cpu); 442 443 if (unlikely(!data) || 444 !data->critical_start || atomic_read(&data->disabled)) 445 return; 446 447 atomic_inc(&data->disabled); 448 449 trace_ctx = tracing_gen_ctx(); 450 __trace_function(tr, ip, parent_ip, trace_ctx); 451 check_critical_timing(tr, data, parent_ip ? : ip, cpu); 452 data->critical_start = 0; 453 atomic_dec(&data->disabled); 454 } 455 456 /* start and stop critical timings used to for stoppage (in idle) */ 457 void start_critical_timings(void) 458 { 459 if (preempt_trace(preempt_count()) || irq_trace()) 460 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 461 } 462 EXPORT_SYMBOL_GPL(start_critical_timings); 463 NOKPROBE_SYMBOL(start_critical_timings); 464 465 void stop_critical_timings(void) 466 { 467 if (preempt_trace(preempt_count()) || irq_trace()) 468 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 469 } 470 EXPORT_SYMBOL_GPL(stop_critical_timings); 471 NOKPROBE_SYMBOL(stop_critical_timings); 472 473 #ifdef CONFIG_FUNCTION_TRACER 474 static bool function_enabled; 475 476 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 477 { 478 int ret; 479 480 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ 481 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION))) 482 return 0; 483 484 if (graph) 485 ret = register_ftrace_graph(&fgraph_ops); 486 else 487 ret = register_ftrace_function(tr->ops); 488 489 if (!ret) 490 function_enabled = true; 491 492 return ret; 493 } 494 495 static void unregister_irqsoff_function(struct trace_array *tr, int graph) 496 { 497 if (!function_enabled) 498 return; 499 500 if (graph) 501 unregister_ftrace_graph(&fgraph_ops); 502 else 503 unregister_ftrace_function(tr->ops); 504 505 function_enabled = false; 506 } 507 508 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 509 { 510 if (!(mask & TRACE_ITER_FUNCTION)) 511 return 0; 512 513 if (set) 514 register_irqsoff_function(tr, is_graph(tr), 1); 515 else 516 unregister_irqsoff_function(tr, is_graph(tr)); 517 return 1; 518 } 519 #else 520 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 521 { 522 return 0; 523 } 524 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { } 525 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 526 { 527 return 0; 528 } 529 #endif /* CONFIG_FUNCTION_TRACER */ 530 531 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) 532 { 533 struct tracer *tracer = tr->current_trace; 534 535 if (irqsoff_function_set(tr, mask, set)) 536 return 0; 537 538 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 539 if (mask & TRACE_ITER_DISPLAY_GRAPH) 540 return irqsoff_display_graph(tr, set); 541 #endif 542 543 return trace_keep_overwrite(tracer, mask, set); 544 } 545 546 static int start_irqsoff_tracer(struct trace_array *tr, int graph) 547 { 548 int ret; 549 550 ret = register_irqsoff_function(tr, graph, 0); 551 552 if (!ret && tracing_is_enabled()) 553 tracer_enabled = 1; 554 else 555 tracer_enabled = 0; 556 557 return ret; 558 } 559 560 static void stop_irqsoff_tracer(struct trace_array *tr, int graph) 561 { 562 tracer_enabled = 0; 563 564 unregister_irqsoff_function(tr, graph); 565 } 566 567 static bool irqsoff_busy; 568 569 static int __irqsoff_tracer_init(struct trace_array *tr) 570 { 571 if (irqsoff_busy) 572 return -EBUSY; 573 574 save_flags = tr->trace_flags; 575 576 /* non overwrite screws up the latency tracers */ 577 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); 578 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); 579 /* without pause, we will produce garbage if another latency occurs */ 580 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1); 581 582 tr->max_latency = 0; 583 irqsoff_trace = tr; 584 /* make sure that the tracer is visible */ 585 smp_wmb(); 586 587 ftrace_init_array_ops(tr, irqsoff_tracer_call); 588 589 /* Only toplevel instance supports graph tracing */ 590 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && 591 is_graph(tr)))) 592 printk(KERN_ERR "failed to start irqsoff tracer\n"); 593 594 irqsoff_busy = true; 595 return 0; 596 } 597 598 static void __irqsoff_tracer_reset(struct trace_array *tr) 599 { 600 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; 601 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; 602 int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE; 603 604 stop_irqsoff_tracer(tr, is_graph(tr)); 605 606 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); 607 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); 608 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag); 609 ftrace_reset_array_ops(tr); 610 611 irqsoff_busy = false; 612 } 613 614 static void irqsoff_tracer_start(struct trace_array *tr) 615 { 616 tracer_enabled = 1; 617 } 618 619 static void irqsoff_tracer_stop(struct trace_array *tr) 620 { 621 tracer_enabled = 0; 622 } 623 624 #ifdef CONFIG_IRQSOFF_TRACER 625 /* 626 * We are only interested in hardirq on/off events: 627 */ 628 void tracer_hardirqs_on(unsigned long a0, unsigned long a1) 629 { 630 if (!preempt_trace(preempt_count()) && irq_trace()) 631 stop_critical_timing(a0, a1); 632 } 633 NOKPROBE_SYMBOL(tracer_hardirqs_on); 634 635 void tracer_hardirqs_off(unsigned long a0, unsigned long a1) 636 { 637 if (!preempt_trace(preempt_count()) && irq_trace()) 638 start_critical_timing(a0, a1); 639 } 640 NOKPROBE_SYMBOL(tracer_hardirqs_off); 641 642 static int irqsoff_tracer_init(struct trace_array *tr) 643 { 644 trace_type = TRACER_IRQS_OFF; 645 646 return __irqsoff_tracer_init(tr); 647 } 648 649 static void irqsoff_tracer_reset(struct trace_array *tr) 650 { 651 __irqsoff_tracer_reset(tr); 652 } 653 654 static struct tracer irqsoff_tracer __read_mostly = 655 { 656 .name = "irqsoff", 657 .init = irqsoff_tracer_init, 658 .reset = irqsoff_tracer_reset, 659 .start = irqsoff_tracer_start, 660 .stop = irqsoff_tracer_stop, 661 .print_max = true, 662 .print_header = irqsoff_print_header, 663 .print_line = irqsoff_print_line, 664 .flag_changed = irqsoff_flag_changed, 665 #ifdef CONFIG_FTRACE_SELFTEST 666 .selftest = trace_selftest_startup_irqsoff, 667 #endif 668 .open = irqsoff_trace_open, 669 .close = irqsoff_trace_close, 670 .allow_instances = true, 671 .use_max_tr = true, 672 }; 673 #endif /* CONFIG_IRQSOFF_TRACER */ 674 675 #ifdef CONFIG_PREEMPT_TRACER 676 void tracer_preempt_on(unsigned long a0, unsigned long a1) 677 { 678 if (preempt_trace(preempt_count()) && !irq_trace()) 679 stop_critical_timing(a0, a1); 680 } 681 682 void tracer_preempt_off(unsigned long a0, unsigned long a1) 683 { 684 if (preempt_trace(preempt_count()) && !irq_trace()) 685 start_critical_timing(a0, a1); 686 } 687 688 static int preemptoff_tracer_init(struct trace_array *tr) 689 { 690 trace_type = TRACER_PREEMPT_OFF; 691 692 return __irqsoff_tracer_init(tr); 693 } 694 695 static void preemptoff_tracer_reset(struct trace_array *tr) 696 { 697 __irqsoff_tracer_reset(tr); 698 } 699 700 static struct tracer preemptoff_tracer __read_mostly = 701 { 702 .name = "preemptoff", 703 .init = preemptoff_tracer_init, 704 .reset = preemptoff_tracer_reset, 705 .start = irqsoff_tracer_start, 706 .stop = irqsoff_tracer_stop, 707 .print_max = true, 708 .print_header = irqsoff_print_header, 709 .print_line = irqsoff_print_line, 710 .flag_changed = irqsoff_flag_changed, 711 #ifdef CONFIG_FTRACE_SELFTEST 712 .selftest = trace_selftest_startup_preemptoff, 713 #endif 714 .open = irqsoff_trace_open, 715 .close = irqsoff_trace_close, 716 .allow_instances = true, 717 .use_max_tr = true, 718 }; 719 #endif /* CONFIG_PREEMPT_TRACER */ 720 721 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 722 723 static int preemptirqsoff_tracer_init(struct trace_array *tr) 724 { 725 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; 726 727 return __irqsoff_tracer_init(tr); 728 } 729 730 static void preemptirqsoff_tracer_reset(struct trace_array *tr) 731 { 732 __irqsoff_tracer_reset(tr); 733 } 734 735 static struct tracer preemptirqsoff_tracer __read_mostly = 736 { 737 .name = "preemptirqsoff", 738 .init = preemptirqsoff_tracer_init, 739 .reset = preemptirqsoff_tracer_reset, 740 .start = irqsoff_tracer_start, 741 .stop = irqsoff_tracer_stop, 742 .print_max = true, 743 .print_header = irqsoff_print_header, 744 .print_line = irqsoff_print_line, 745 .flag_changed = irqsoff_flag_changed, 746 #ifdef CONFIG_FTRACE_SELFTEST 747 .selftest = trace_selftest_startup_preemptirqsoff, 748 #endif 749 .open = irqsoff_trace_open, 750 .close = irqsoff_trace_close, 751 .allow_instances = true, 752 .use_max_tr = true, 753 }; 754 #endif 755 756 __init static int init_irqsoff_tracer(void) 757 { 758 #ifdef CONFIG_IRQSOFF_TRACER 759 register_tracer(&irqsoff_tracer); 760 #endif 761 #ifdef CONFIG_PREEMPT_TRACER 762 register_tracer(&preemptoff_tracer); 763 #endif 764 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 765 register_tracer(&preemptirqsoff_tracer); 766 #endif 767 768 return 0; 769 } 770 core_initcall(init_irqsoff_tracer); 771 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */ 772