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 = 0; 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 *calltime = trace_clock_local(); 207 trace_ctx = tracing_gen_ctx_flags(flags); 208 ret = __trace_graph_entry(tr, trace, trace_ctx); 209 } 210 local_dec(&data->disabled); 211 212 return ret; 213 } 214 215 static void irqsoff_graph_return(struct ftrace_graph_ret *trace, 216 struct fgraph_ops *gops, 217 struct ftrace_regs *fregs) 218 { 219 struct trace_array *tr = irqsoff_trace; 220 struct trace_array_cpu *data; 221 unsigned long flags; 222 unsigned int trace_ctx; 223 u64 *calltime; 224 u64 rettime; 225 int size; 226 227 ftrace_graph_addr_finish(gops, trace); 228 229 if (!func_prolog_dec(tr, &data, &flags)) 230 return; 231 232 rettime = trace_clock_local(); 233 calltime = fgraph_retrieve_data(gops->idx, &size); 234 if (calltime) { 235 trace_ctx = tracing_gen_ctx_flags(flags); 236 __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); 237 } 238 local_dec(&data->disabled); 239 } 240 241 static struct fgraph_ops fgraph_ops = { 242 .entryfunc = &irqsoff_graph_entry, 243 .retfunc = &irqsoff_graph_return, 244 }; 245 246 static void irqsoff_trace_open(struct trace_iterator *iter) 247 { 248 if (is_graph(iter->tr)) 249 graph_trace_open(iter); 250 } 251 252 static void irqsoff_trace_close(struct trace_iterator *iter) 253 { 254 if (iter->private) 255 graph_trace_close(iter); 256 } 257 258 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \ 259 TRACE_GRAPH_PRINT_PROC | \ 260 TRACE_GRAPH_PRINT_REL_TIME | \ 261 TRACE_GRAPH_PRINT_DURATION) 262 263 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 264 { 265 /* 266 * In graph mode call the graph tracer output function, 267 * otherwise go with the TRACE_FN event handler 268 */ 269 if (is_graph(iter->tr)) 270 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); 271 272 return TRACE_TYPE_UNHANDLED; 273 } 274 275 static void irqsoff_print_header(struct seq_file *s) 276 { 277 struct trace_array *tr = irqsoff_trace; 278 279 if (is_graph(tr)) 280 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); 281 else 282 trace_default_header(s); 283 } 284 285 static void 286 __trace_function(struct trace_array *tr, 287 unsigned long ip, unsigned long parent_ip, 288 unsigned int trace_ctx) 289 { 290 if (is_graph(tr)) 291 trace_graph_function(tr, ip, parent_ip, trace_ctx); 292 else 293 trace_function(tr, ip, parent_ip, trace_ctx, NULL); 294 } 295 296 #else 297 static inline void 298 __trace_function(struct trace_array *tr, 299 unsigned long ip, unsigned long parent_ip, 300 unsigned int trace_ctx) 301 { 302 return trace_function(tr, ip, parent_ip, trace_ctx, NULL); 303 } 304 305 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 306 { 307 return TRACE_TYPE_UNHANDLED; 308 } 309 310 static void irqsoff_trace_open(struct trace_iterator *iter) { } 311 static void irqsoff_trace_close(struct trace_iterator *iter) { } 312 313 #ifdef CONFIG_FUNCTION_TRACER 314 static void irqsoff_print_header(struct seq_file *s) 315 { 316 trace_default_header(s); 317 } 318 #else 319 static void irqsoff_print_header(struct seq_file *s) 320 { 321 trace_latency_header(s); 322 } 323 #endif /* CONFIG_FUNCTION_TRACER */ 324 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 325 326 /* 327 * Should this new latency be reported/recorded? 328 */ 329 static bool report_latency(struct trace_array *tr, u64 delta) 330 { 331 if (tracing_thresh) { 332 if (delta < tracing_thresh) 333 return false; 334 } else { 335 if (delta <= tr->max_latency) 336 return false; 337 } 338 return true; 339 } 340 341 static void 342 check_critical_timing(struct trace_array *tr, 343 struct trace_array_cpu *data, 344 unsigned long parent_ip, 345 int cpu) 346 { 347 u64 T0, T1, delta; 348 unsigned long flags; 349 unsigned int trace_ctx; 350 351 T0 = data->preempt_timestamp; 352 T1 = ftrace_now(cpu); 353 delta = T1-T0; 354 355 trace_ctx = tracing_gen_ctx(); 356 357 if (!report_latency(tr, delta)) 358 goto out; 359 360 raw_spin_lock_irqsave(&max_trace_lock, flags); 361 362 /* check if we are still the max latency */ 363 if (!report_latency(tr, delta)) 364 goto out_unlock; 365 366 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 367 /* Skip 5 functions to get to the irq/preempt enable function */ 368 __trace_stack(tr, trace_ctx, 5); 369 370 if (data->critical_sequence != max_sequence) 371 goto out_unlock; 372 373 data->critical_end = parent_ip; 374 375 if (likely(!is_tracing_stopped())) { 376 tr->max_latency = delta; 377 update_max_tr_single(tr, current, cpu); 378 } 379 380 max_sequence++; 381 382 out_unlock: 383 raw_spin_unlock_irqrestore(&max_trace_lock, flags); 384 385 out: 386 data->critical_sequence = max_sequence; 387 data->preempt_timestamp = ftrace_now(cpu); 388 __trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx); 389 } 390 391 static nokprobe_inline void 392 start_critical_timing(unsigned long ip, unsigned long parent_ip) 393 { 394 int cpu; 395 struct trace_array *tr = irqsoff_trace; 396 struct trace_array_cpu *data; 397 long disabled; 398 399 if (!tracer_enabled || !tracing_is_enabled()) 400 return; 401 402 cpu = raw_smp_processor_id(); 403 404 if (per_cpu(tracing_cpu, cpu)) 405 return; 406 407 data = per_cpu_ptr(tr->array_buffer.data, cpu); 408 409 if (unlikely(!data) || local_read(&data->disabled)) 410 return; 411 412 disabled = local_inc_return(&data->disabled); 413 414 if (disabled == 1) { 415 data->critical_sequence = max_sequence; 416 data->preempt_timestamp = ftrace_now(cpu); 417 data->critical_start = parent_ip ? : ip; 418 419 __trace_function(tr, ip, parent_ip, tracing_gen_ctx()); 420 421 per_cpu(tracing_cpu, cpu) = 1; 422 } 423 424 local_dec(&data->disabled); 425 } 426 427 static nokprobe_inline void 428 stop_critical_timing(unsigned long ip, unsigned long parent_ip) 429 { 430 int cpu; 431 struct trace_array *tr = irqsoff_trace; 432 struct trace_array_cpu *data; 433 unsigned int trace_ctx; 434 long disabled; 435 436 cpu = raw_smp_processor_id(); 437 /* Always clear the tracing cpu on stopping the trace */ 438 if (unlikely(per_cpu(tracing_cpu, cpu))) 439 per_cpu(tracing_cpu, cpu) = 0; 440 else 441 return; 442 443 if (!tracer_enabled || !tracing_is_enabled()) 444 return; 445 446 data = per_cpu_ptr(tr->array_buffer.data, cpu); 447 448 if (unlikely(!data) || 449 !data->critical_start || local_read(&data->disabled)) 450 return; 451 452 disabled = local_inc_return(&data->disabled); 453 454 if (disabled == 1) { 455 trace_ctx = tracing_gen_ctx(); 456 __trace_function(tr, ip, parent_ip, trace_ctx); 457 check_critical_timing(tr, data, parent_ip ? : ip, cpu); 458 data->critical_start = 0; 459 } 460 461 local_dec(&data->disabled); 462 } 463 464 /* start and stop critical timings used to for stoppage (in idle) */ 465 void start_critical_timings(void) 466 { 467 if (preempt_trace(preempt_count()) || irq_trace()) 468 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 469 } 470 EXPORT_SYMBOL_GPL(start_critical_timings); 471 NOKPROBE_SYMBOL(start_critical_timings); 472 473 void stop_critical_timings(void) 474 { 475 if (preempt_trace(preempt_count()) || irq_trace()) 476 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 477 } 478 EXPORT_SYMBOL_GPL(stop_critical_timings); 479 NOKPROBE_SYMBOL(stop_critical_timings); 480 481 #ifdef CONFIG_FUNCTION_TRACER 482 static bool function_enabled; 483 484 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 485 { 486 int ret; 487 488 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ 489 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION))) 490 return 0; 491 492 if (graph) 493 ret = register_ftrace_graph(&fgraph_ops); 494 else 495 ret = register_ftrace_function(tr->ops); 496 497 if (!ret) 498 function_enabled = true; 499 500 return ret; 501 } 502 503 static void unregister_irqsoff_function(struct trace_array *tr, int graph) 504 { 505 if (!function_enabled) 506 return; 507 508 if (graph) 509 unregister_ftrace_graph(&fgraph_ops); 510 else 511 unregister_ftrace_function(tr->ops); 512 513 function_enabled = false; 514 } 515 516 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 517 { 518 if (!(mask & TRACE_ITER_FUNCTION)) 519 return 0; 520 521 if (set) 522 register_irqsoff_function(tr, is_graph(tr), 1); 523 else 524 unregister_irqsoff_function(tr, is_graph(tr)); 525 return 1; 526 } 527 #else 528 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 529 { 530 return 0; 531 } 532 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { } 533 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 534 { 535 return 0; 536 } 537 #endif /* CONFIG_FUNCTION_TRACER */ 538 539 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) 540 { 541 struct tracer *tracer = tr->current_trace; 542 543 if (irqsoff_function_set(tr, mask, set)) 544 return 0; 545 546 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 547 if (mask & TRACE_ITER_DISPLAY_GRAPH) 548 return irqsoff_display_graph(tr, set); 549 #endif 550 551 return trace_keep_overwrite(tracer, mask, set); 552 } 553 554 static int start_irqsoff_tracer(struct trace_array *tr, int graph) 555 { 556 int ret; 557 558 ret = register_irqsoff_function(tr, graph, 0); 559 560 if (!ret && tracing_is_enabled()) 561 tracer_enabled = 1; 562 else 563 tracer_enabled = 0; 564 565 return ret; 566 } 567 568 static void stop_irqsoff_tracer(struct trace_array *tr, int graph) 569 { 570 tracer_enabled = 0; 571 572 unregister_irqsoff_function(tr, graph); 573 } 574 575 static bool irqsoff_busy; 576 577 static int __irqsoff_tracer_init(struct trace_array *tr) 578 { 579 if (irqsoff_busy) 580 return -EBUSY; 581 582 save_flags = tr->trace_flags; 583 584 /* non overwrite screws up the latency tracers */ 585 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); 586 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); 587 /* without pause, we will produce garbage if another latency occurs */ 588 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1); 589 590 tr->max_latency = 0; 591 irqsoff_trace = tr; 592 /* make sure that the tracer is visible */ 593 smp_wmb(); 594 595 ftrace_init_array_ops(tr, irqsoff_tracer_call); 596 597 /* Only toplevel instance supports graph tracing */ 598 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && 599 is_graph(tr)))) 600 printk(KERN_ERR "failed to start irqsoff tracer\n"); 601 602 irqsoff_busy = true; 603 return 0; 604 } 605 606 static void __irqsoff_tracer_reset(struct trace_array *tr) 607 { 608 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; 609 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; 610 int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE; 611 612 stop_irqsoff_tracer(tr, is_graph(tr)); 613 614 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); 615 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); 616 set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag); 617 ftrace_reset_array_ops(tr); 618 619 irqsoff_busy = false; 620 } 621 622 static void irqsoff_tracer_start(struct trace_array *tr) 623 { 624 tracer_enabled = 1; 625 } 626 627 static void irqsoff_tracer_stop(struct trace_array *tr) 628 { 629 tracer_enabled = 0; 630 } 631 632 #ifdef CONFIG_IRQSOFF_TRACER 633 /* 634 * We are only interested in hardirq on/off events: 635 */ 636 void tracer_hardirqs_on(unsigned long a0, unsigned long a1) 637 { 638 if (!preempt_trace(preempt_count()) && irq_trace()) 639 stop_critical_timing(a0, a1); 640 } 641 NOKPROBE_SYMBOL(tracer_hardirqs_on); 642 643 void tracer_hardirqs_off(unsigned long a0, unsigned long a1) 644 { 645 if (!preempt_trace(preempt_count()) && irq_trace()) 646 start_critical_timing(a0, a1); 647 } 648 NOKPROBE_SYMBOL(tracer_hardirqs_off); 649 650 static int irqsoff_tracer_init(struct trace_array *tr) 651 { 652 trace_type = TRACER_IRQS_OFF; 653 654 return __irqsoff_tracer_init(tr); 655 } 656 657 static void irqsoff_tracer_reset(struct trace_array *tr) 658 { 659 __irqsoff_tracer_reset(tr); 660 } 661 662 static struct tracer irqsoff_tracer __read_mostly = 663 { 664 .name = "irqsoff", 665 .init = irqsoff_tracer_init, 666 .reset = irqsoff_tracer_reset, 667 .start = irqsoff_tracer_start, 668 .stop = irqsoff_tracer_stop, 669 .print_max = true, 670 .print_header = irqsoff_print_header, 671 .print_line = irqsoff_print_line, 672 .flag_changed = irqsoff_flag_changed, 673 #ifdef CONFIG_FTRACE_SELFTEST 674 .selftest = trace_selftest_startup_irqsoff, 675 #endif 676 .open = irqsoff_trace_open, 677 .close = irqsoff_trace_close, 678 .allow_instances = true, 679 .use_max_tr = true, 680 }; 681 #endif /* CONFIG_IRQSOFF_TRACER */ 682 683 #ifdef CONFIG_PREEMPT_TRACER 684 void tracer_preempt_on(unsigned long a0, unsigned long a1) 685 { 686 if (preempt_trace(preempt_count()) && !irq_trace()) 687 stop_critical_timing(a0, a1); 688 } 689 690 void tracer_preempt_off(unsigned long a0, unsigned long a1) 691 { 692 if (preempt_trace(preempt_count()) && !irq_trace()) 693 start_critical_timing(a0, a1); 694 } 695 696 static int preemptoff_tracer_init(struct trace_array *tr) 697 { 698 trace_type = TRACER_PREEMPT_OFF; 699 700 return __irqsoff_tracer_init(tr); 701 } 702 703 static void preemptoff_tracer_reset(struct trace_array *tr) 704 { 705 __irqsoff_tracer_reset(tr); 706 } 707 708 static struct tracer preemptoff_tracer __read_mostly = 709 { 710 .name = "preemptoff", 711 .init = preemptoff_tracer_init, 712 .reset = preemptoff_tracer_reset, 713 .start = irqsoff_tracer_start, 714 .stop = irqsoff_tracer_stop, 715 .print_max = true, 716 .print_header = irqsoff_print_header, 717 .print_line = irqsoff_print_line, 718 .flag_changed = irqsoff_flag_changed, 719 #ifdef CONFIG_FTRACE_SELFTEST 720 .selftest = trace_selftest_startup_preemptoff, 721 #endif 722 .open = irqsoff_trace_open, 723 .close = irqsoff_trace_close, 724 .allow_instances = true, 725 .use_max_tr = true, 726 }; 727 #endif /* CONFIG_PREEMPT_TRACER */ 728 729 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 730 731 static int preemptirqsoff_tracer_init(struct trace_array *tr) 732 { 733 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; 734 735 return __irqsoff_tracer_init(tr); 736 } 737 738 static void preemptirqsoff_tracer_reset(struct trace_array *tr) 739 { 740 __irqsoff_tracer_reset(tr); 741 } 742 743 static struct tracer preemptirqsoff_tracer __read_mostly = 744 { 745 .name = "preemptirqsoff", 746 .init = preemptirqsoff_tracer_init, 747 .reset = preemptirqsoff_tracer_reset, 748 .start = irqsoff_tracer_start, 749 .stop = irqsoff_tracer_stop, 750 .print_max = true, 751 .print_header = irqsoff_print_header, 752 .print_line = irqsoff_print_line, 753 .flag_changed = irqsoff_flag_changed, 754 #ifdef CONFIG_FTRACE_SELFTEST 755 .selftest = trace_selftest_startup_preemptirqsoff, 756 #endif 757 .open = irqsoff_trace_open, 758 .close = irqsoff_trace_close, 759 .allow_instances = true, 760 .use_max_tr = true, 761 }; 762 #endif 763 764 __init static int init_irqsoff_tracer(void) 765 { 766 #ifdef CONFIG_IRQSOFF_TRACER 767 register_tracer(&irqsoff_tracer); 768 #endif 769 #ifdef CONFIG_PREEMPT_TRACER 770 register_tracer(&preemptoff_tracer); 771 #endif 772 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 773 register_tracer(&preemptirqsoff_tracer); 774 #endif 775 776 return 0; 777 } 778 core_initcall(init_irqsoff_tracer); 779 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */ 780