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