1 /* 2 * trace irqs off critical timings 3 * 4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> 5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> 6 * 7 * From code in the latency_tracer, that is: 8 * 9 * Copyright (C) 2004-2006 Ingo Molnar 10 * Copyright (C) 2004 Nadia Yvette Chambers 11 */ 12 #include <linux/kallsyms.h> 13 #include <linux/uaccess.h> 14 #include <linux/module.h> 15 #include <linux/ftrace.h> 16 17 #include "trace.h" 18 19 #define CREATE_TRACE_POINTS 20 #include <trace/events/preemptirq.h> 21 22 #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) 23 static struct trace_array *irqsoff_trace __read_mostly; 24 static int tracer_enabled __read_mostly; 25 26 static DEFINE_PER_CPU(int, tracing_cpu); 27 28 static DEFINE_RAW_SPINLOCK(max_trace_lock); 29 30 enum { 31 TRACER_IRQS_OFF = (1 << 1), 32 TRACER_PREEMPT_OFF = (1 << 2), 33 }; 34 35 static int trace_type __read_mostly; 36 37 static int save_flags; 38 39 static void stop_irqsoff_tracer(struct trace_array *tr, int graph); 40 static int start_irqsoff_tracer(struct trace_array *tr, int graph); 41 42 #ifdef CONFIG_PREEMPT_TRACER 43 static inline int 44 preempt_trace(void) 45 { 46 return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count()); 47 } 48 #else 49 # define preempt_trace() (0) 50 #endif 51 52 #ifdef CONFIG_IRQSOFF_TRACER 53 static inline int 54 irq_trace(void) 55 { 56 return ((trace_type & TRACER_IRQS_OFF) && 57 irqs_disabled()); 58 } 59 #else 60 # define irq_trace() (0) 61 #endif 62 63 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 64 static int irqsoff_display_graph(struct trace_array *tr, int set); 65 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH) 66 #else 67 static inline int irqsoff_display_graph(struct trace_array *tr, int set) 68 { 69 return -EINVAL; 70 } 71 # define is_graph(tr) false 72 #endif 73 74 /* 75 * Sequence count - we record it when starting a measurement and 76 * skip the latency if the sequence has changed - some other section 77 * did a maximum and could disturb our measurement with serial console 78 * printouts, etc. Truly coinciding maximum latencies should be rare 79 * and what happens together happens separately as well, so this doesn't 80 * decrease the validity of the maximum found: 81 */ 82 static __cacheline_aligned_in_smp unsigned long max_sequence; 83 84 #ifdef CONFIG_FUNCTION_TRACER 85 /* 86 * Prologue for the preempt and irqs off function tracers. 87 * 88 * Returns 1 if it is OK to continue, and data->disabled is 89 * incremented. 90 * 0 if the trace is to be ignored, and data->disabled 91 * is kept the same. 92 * 93 * Note, this function is also used outside this ifdef but 94 * inside the #ifdef of the function graph tracer below. 95 * This is OK, since the function graph tracer is 96 * dependent on the function tracer. 97 */ 98 static int func_prolog_dec(struct trace_array *tr, 99 struct trace_array_cpu **data, 100 unsigned long *flags) 101 { 102 long disabled; 103 int cpu; 104 105 /* 106 * Does not matter if we preempt. We test the flags 107 * afterward, to see if irqs are disabled or not. 108 * If we preempt and get a false positive, the flags 109 * test will fail. 110 */ 111 cpu = raw_smp_processor_id(); 112 if (likely(!per_cpu(tracing_cpu, cpu))) 113 return 0; 114 115 local_save_flags(*flags); 116 /* 117 * Slight chance to get a false positive on tracing_cpu, 118 * although I'm starting to think there isn't a chance. 119 * Leave this for now just to be paranoid. 120 */ 121 if (!irqs_disabled_flags(*flags) && !preempt_count()) 122 return 0; 123 124 *data = per_cpu_ptr(tr->trace_buffer.data, cpu); 125 disabled = atomic_inc_return(&(*data)->disabled); 126 127 if (likely(disabled == 1)) 128 return 1; 129 130 atomic_dec(&(*data)->disabled); 131 132 return 0; 133 } 134 135 /* 136 * irqsoff uses its own tracer function to keep the overhead down: 137 */ 138 static void 139 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip, 140 struct ftrace_ops *op, struct pt_regs *pt_regs) 141 { 142 struct trace_array *tr = irqsoff_trace; 143 struct trace_array_cpu *data; 144 unsigned long flags; 145 146 if (!func_prolog_dec(tr, &data, &flags)) 147 return; 148 149 trace_function(tr, ip, parent_ip, flags, preempt_count()); 150 151 atomic_dec(&data->disabled); 152 } 153 #endif /* CONFIG_FUNCTION_TRACER */ 154 155 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 156 static int irqsoff_display_graph(struct trace_array *tr, int set) 157 { 158 int cpu; 159 160 if (!(is_graph(tr) ^ set)) 161 return 0; 162 163 stop_irqsoff_tracer(irqsoff_trace, !set); 164 165 for_each_possible_cpu(cpu) 166 per_cpu(tracing_cpu, cpu) = 0; 167 168 tr->max_latency = 0; 169 tracing_reset_online_cpus(&irqsoff_trace->trace_buffer); 170 171 return start_irqsoff_tracer(irqsoff_trace, set); 172 } 173 174 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace) 175 { 176 struct trace_array *tr = irqsoff_trace; 177 struct trace_array_cpu *data; 178 unsigned long flags; 179 int ret; 180 int pc; 181 182 if (ftrace_graph_ignore_func(trace)) 183 return 0; 184 /* 185 * Do not trace a function if it's filtered by set_graph_notrace. 186 * Make the index of ret stack negative to indicate that it should 187 * ignore further functions. But it needs its own ret stack entry 188 * to recover the original index in order to continue tracing after 189 * returning from the function. 190 */ 191 if (ftrace_graph_notrace_addr(trace->func)) 192 return 1; 193 194 if (!func_prolog_dec(tr, &data, &flags)) 195 return 0; 196 197 pc = preempt_count(); 198 ret = __trace_graph_entry(tr, trace, flags, pc); 199 atomic_dec(&data->disabled); 200 201 return ret; 202 } 203 204 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) 205 { 206 struct trace_array *tr = irqsoff_trace; 207 struct trace_array_cpu *data; 208 unsigned long flags; 209 int pc; 210 211 if (!func_prolog_dec(tr, &data, &flags)) 212 return; 213 214 pc = preempt_count(); 215 __trace_graph_return(tr, trace, flags, pc); 216 atomic_dec(&data->disabled); 217 } 218 219 static void irqsoff_trace_open(struct trace_iterator *iter) 220 { 221 if (is_graph(iter->tr)) 222 graph_trace_open(iter); 223 224 } 225 226 static void irqsoff_trace_close(struct trace_iterator *iter) 227 { 228 if (iter->private) 229 graph_trace_close(iter); 230 } 231 232 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \ 233 TRACE_GRAPH_PRINT_PROC | \ 234 TRACE_GRAPH_PRINT_ABS_TIME | \ 235 TRACE_GRAPH_PRINT_DURATION) 236 237 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 238 { 239 /* 240 * In graph mode call the graph tracer output function, 241 * otherwise go with the TRACE_FN event handler 242 */ 243 if (is_graph(iter->tr)) 244 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); 245 246 return TRACE_TYPE_UNHANDLED; 247 } 248 249 static void irqsoff_print_header(struct seq_file *s) 250 { 251 struct trace_array *tr = irqsoff_trace; 252 253 if (is_graph(tr)) 254 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); 255 else 256 trace_default_header(s); 257 } 258 259 static void 260 __trace_function(struct trace_array *tr, 261 unsigned long ip, unsigned long parent_ip, 262 unsigned long flags, int pc) 263 { 264 if (is_graph(tr)) 265 trace_graph_function(tr, ip, parent_ip, flags, pc); 266 else 267 trace_function(tr, ip, parent_ip, flags, pc); 268 } 269 270 #else 271 #define __trace_function trace_function 272 273 #ifdef CONFIG_FUNCTION_TRACER 274 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace) 275 { 276 return -1; 277 } 278 #endif 279 280 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter) 281 { 282 return TRACE_TYPE_UNHANDLED; 283 } 284 285 static void irqsoff_trace_open(struct trace_iterator *iter) { } 286 static void irqsoff_trace_close(struct trace_iterator *iter) { } 287 288 #ifdef CONFIG_FUNCTION_TRACER 289 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { } 290 static void irqsoff_print_header(struct seq_file *s) 291 { 292 trace_default_header(s); 293 } 294 #else 295 static void irqsoff_print_header(struct seq_file *s) 296 { 297 trace_latency_header(s); 298 } 299 #endif /* CONFIG_FUNCTION_TRACER */ 300 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 301 302 /* 303 * Should this new latency be reported/recorded? 304 */ 305 static bool report_latency(struct trace_array *tr, u64 delta) 306 { 307 if (tracing_thresh) { 308 if (delta < tracing_thresh) 309 return false; 310 } else { 311 if (delta <= tr->max_latency) 312 return false; 313 } 314 return true; 315 } 316 317 static void 318 check_critical_timing(struct trace_array *tr, 319 struct trace_array_cpu *data, 320 unsigned long parent_ip, 321 int cpu) 322 { 323 u64 T0, T1, delta; 324 unsigned long flags; 325 int pc; 326 327 T0 = data->preempt_timestamp; 328 T1 = ftrace_now(cpu); 329 delta = T1-T0; 330 331 local_save_flags(flags); 332 333 pc = preempt_count(); 334 335 if (!report_latency(tr, delta)) 336 goto out; 337 338 raw_spin_lock_irqsave(&max_trace_lock, flags); 339 340 /* check if we are still the max latency */ 341 if (!report_latency(tr, delta)) 342 goto out_unlock; 343 344 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); 345 /* Skip 5 functions to get to the irq/preempt enable function */ 346 __trace_stack(tr, flags, 5, pc); 347 348 if (data->critical_sequence != max_sequence) 349 goto out_unlock; 350 351 data->critical_end = parent_ip; 352 353 if (likely(!is_tracing_stopped())) { 354 tr->max_latency = delta; 355 update_max_tr_single(tr, current, cpu); 356 } 357 358 max_sequence++; 359 360 out_unlock: 361 raw_spin_unlock_irqrestore(&max_trace_lock, flags); 362 363 out: 364 data->critical_sequence = max_sequence; 365 data->preempt_timestamp = ftrace_now(cpu); 366 __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); 367 } 368 369 static inline void 370 start_critical_timing(unsigned long ip, unsigned long parent_ip) 371 { 372 int cpu; 373 struct trace_array *tr = irqsoff_trace; 374 struct trace_array_cpu *data; 375 unsigned long flags; 376 377 if (!tracer_enabled || !tracing_is_enabled()) 378 return; 379 380 cpu = raw_smp_processor_id(); 381 382 if (per_cpu(tracing_cpu, cpu)) 383 return; 384 385 data = per_cpu_ptr(tr->trace_buffer.data, cpu); 386 387 if (unlikely(!data) || atomic_read(&data->disabled)) 388 return; 389 390 atomic_inc(&data->disabled); 391 392 data->critical_sequence = max_sequence; 393 data->preempt_timestamp = ftrace_now(cpu); 394 data->critical_start = parent_ip ? : ip; 395 396 local_save_flags(flags); 397 398 __trace_function(tr, ip, parent_ip, flags, preempt_count()); 399 400 per_cpu(tracing_cpu, cpu) = 1; 401 402 atomic_dec(&data->disabled); 403 } 404 405 static inline void 406 stop_critical_timing(unsigned long ip, unsigned long parent_ip) 407 { 408 int cpu; 409 struct trace_array *tr = irqsoff_trace; 410 struct trace_array_cpu *data; 411 unsigned long flags; 412 413 cpu = raw_smp_processor_id(); 414 /* Always clear the tracing cpu on stopping the trace */ 415 if (unlikely(per_cpu(tracing_cpu, cpu))) 416 per_cpu(tracing_cpu, cpu) = 0; 417 else 418 return; 419 420 if (!tracer_enabled || !tracing_is_enabled()) 421 return; 422 423 data = per_cpu_ptr(tr->trace_buffer.data, cpu); 424 425 if (unlikely(!data) || 426 !data->critical_start || atomic_read(&data->disabled)) 427 return; 428 429 atomic_inc(&data->disabled); 430 431 local_save_flags(flags); 432 __trace_function(tr, ip, parent_ip, flags, preempt_count()); 433 check_critical_timing(tr, data, parent_ip ? : ip, cpu); 434 data->critical_start = 0; 435 atomic_dec(&data->disabled); 436 } 437 438 /* start and stop critical timings used to for stoppage (in idle) */ 439 void start_critical_timings(void) 440 { 441 if (preempt_trace() || irq_trace()) 442 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 443 } 444 EXPORT_SYMBOL_GPL(start_critical_timings); 445 446 void stop_critical_timings(void) 447 { 448 if (preempt_trace() || irq_trace()) 449 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 450 } 451 EXPORT_SYMBOL_GPL(stop_critical_timings); 452 453 #ifdef CONFIG_IRQSOFF_TRACER 454 #ifdef CONFIG_PROVE_LOCKING 455 void time_hardirqs_on(unsigned long a0, unsigned long a1) 456 { 457 if (!preempt_trace() && irq_trace()) 458 stop_critical_timing(a0, a1); 459 } 460 461 void time_hardirqs_off(unsigned long a0, unsigned long a1) 462 { 463 if (!preempt_trace() && irq_trace()) 464 start_critical_timing(a0, a1); 465 } 466 467 #else /* !CONFIG_PROVE_LOCKING */ 468 469 /* 470 * We are only interested in hardirq on/off events: 471 */ 472 static inline void tracer_hardirqs_on(void) 473 { 474 if (!preempt_trace() && irq_trace()) 475 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 476 } 477 478 static inline void tracer_hardirqs_off(void) 479 { 480 if (!preempt_trace() && irq_trace()) 481 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); 482 } 483 484 static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) 485 { 486 if (!preempt_trace() && irq_trace()) 487 stop_critical_timing(CALLER_ADDR0, caller_addr); 488 } 489 490 static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) 491 { 492 if (!preempt_trace() && irq_trace()) 493 start_critical_timing(CALLER_ADDR0, caller_addr); 494 } 495 496 #endif /* CONFIG_PROVE_LOCKING */ 497 #endif /* CONFIG_IRQSOFF_TRACER */ 498 499 #ifdef CONFIG_PREEMPT_TRACER 500 static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) 501 { 502 if (preempt_trace() && !irq_trace()) 503 stop_critical_timing(a0, a1); 504 } 505 506 static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) 507 { 508 if (preempt_trace() && !irq_trace()) 509 start_critical_timing(a0, a1); 510 } 511 #endif /* CONFIG_PREEMPT_TRACER */ 512 513 #ifdef CONFIG_FUNCTION_TRACER 514 static bool function_enabled; 515 516 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 517 { 518 int ret; 519 520 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ 521 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION))) 522 return 0; 523 524 if (graph) 525 ret = register_ftrace_graph(&irqsoff_graph_return, 526 &irqsoff_graph_entry); 527 else 528 ret = register_ftrace_function(tr->ops); 529 530 if (!ret) 531 function_enabled = true; 532 533 return ret; 534 } 535 536 static void unregister_irqsoff_function(struct trace_array *tr, int graph) 537 { 538 if (!function_enabled) 539 return; 540 541 if (graph) 542 unregister_ftrace_graph(); 543 else 544 unregister_ftrace_function(tr->ops); 545 546 function_enabled = false; 547 } 548 549 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 550 { 551 if (!(mask & TRACE_ITER_FUNCTION)) 552 return 0; 553 554 if (set) 555 register_irqsoff_function(tr, is_graph(tr), 1); 556 else 557 unregister_irqsoff_function(tr, is_graph(tr)); 558 return 1; 559 } 560 #else 561 static int register_irqsoff_function(struct trace_array *tr, int graph, int set) 562 { 563 return 0; 564 } 565 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { } 566 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set) 567 { 568 return 0; 569 } 570 #endif /* CONFIG_FUNCTION_TRACER */ 571 572 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) 573 { 574 struct tracer *tracer = tr->current_trace; 575 576 if (irqsoff_function_set(tr, mask, set)) 577 return 0; 578 579 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 580 if (mask & TRACE_ITER_DISPLAY_GRAPH) 581 return irqsoff_display_graph(tr, set); 582 #endif 583 584 return trace_keep_overwrite(tracer, mask, set); 585 } 586 587 static int start_irqsoff_tracer(struct trace_array *tr, int graph) 588 { 589 int ret; 590 591 ret = register_irqsoff_function(tr, graph, 0); 592 593 if (!ret && tracing_is_enabled()) 594 tracer_enabled = 1; 595 else 596 tracer_enabled = 0; 597 598 return ret; 599 } 600 601 static void stop_irqsoff_tracer(struct trace_array *tr, int graph) 602 { 603 tracer_enabled = 0; 604 605 unregister_irqsoff_function(tr, graph); 606 } 607 608 static bool irqsoff_busy; 609 610 static int __irqsoff_tracer_init(struct trace_array *tr) 611 { 612 if (irqsoff_busy) 613 return -EBUSY; 614 615 save_flags = tr->trace_flags; 616 617 /* non overwrite screws up the latency tracers */ 618 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); 619 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); 620 621 tr->max_latency = 0; 622 irqsoff_trace = tr; 623 /* make sure that the tracer is visible */ 624 smp_wmb(); 625 626 ftrace_init_array_ops(tr, irqsoff_tracer_call); 627 628 /* Only toplevel instance supports graph tracing */ 629 if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && 630 is_graph(tr)))) 631 printk(KERN_ERR "failed to start irqsoff tracer\n"); 632 633 irqsoff_busy = true; 634 return 0; 635 } 636 637 static void irqsoff_tracer_reset(struct trace_array *tr) 638 { 639 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; 640 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; 641 642 stop_irqsoff_tracer(tr, is_graph(tr)); 643 644 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); 645 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); 646 ftrace_reset_array_ops(tr); 647 648 irqsoff_busy = false; 649 } 650 651 static void irqsoff_tracer_start(struct trace_array *tr) 652 { 653 tracer_enabled = 1; 654 } 655 656 static void irqsoff_tracer_stop(struct trace_array *tr) 657 { 658 tracer_enabled = 0; 659 } 660 661 #ifdef CONFIG_IRQSOFF_TRACER 662 static int irqsoff_tracer_init(struct trace_array *tr) 663 { 664 trace_type = TRACER_IRQS_OFF; 665 666 return __irqsoff_tracer_init(tr); 667 } 668 static struct tracer irqsoff_tracer __read_mostly = 669 { 670 .name = "irqsoff", 671 .init = irqsoff_tracer_init, 672 .reset = irqsoff_tracer_reset, 673 .start = irqsoff_tracer_start, 674 .stop = irqsoff_tracer_stop, 675 .print_max = true, 676 .print_header = irqsoff_print_header, 677 .print_line = irqsoff_print_line, 678 .flag_changed = irqsoff_flag_changed, 679 #ifdef CONFIG_FTRACE_SELFTEST 680 .selftest = trace_selftest_startup_irqsoff, 681 #endif 682 .open = irqsoff_trace_open, 683 .close = irqsoff_trace_close, 684 .allow_instances = true, 685 .use_max_tr = true, 686 }; 687 # define register_irqsoff(trace) register_tracer(&trace) 688 #else 689 # define register_irqsoff(trace) do { } while (0) 690 #endif 691 692 #ifdef CONFIG_PREEMPT_TRACER 693 static int preemptoff_tracer_init(struct trace_array *tr) 694 { 695 trace_type = TRACER_PREEMPT_OFF; 696 697 return __irqsoff_tracer_init(tr); 698 } 699 700 static struct tracer preemptoff_tracer __read_mostly = 701 { 702 .name = "preemptoff", 703 .init = preemptoff_tracer_init, 704 .reset = irqsoff_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 # define register_preemptoff(trace) register_tracer(&trace) 720 #else 721 # define register_preemptoff(trace) do { } while (0) 722 #endif 723 724 #if defined(CONFIG_IRQSOFF_TRACER) && \ 725 defined(CONFIG_PREEMPT_TRACER) 726 727 static int preemptirqsoff_tracer_init(struct trace_array *tr) 728 { 729 trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; 730 731 return __irqsoff_tracer_init(tr); 732 } 733 734 static struct tracer preemptirqsoff_tracer __read_mostly = 735 { 736 .name = "preemptirqsoff", 737 .init = preemptirqsoff_tracer_init, 738 .reset = irqsoff_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 }; 753 754 # define register_preemptirqsoff(trace) register_tracer(&trace) 755 #else 756 # define register_preemptirqsoff(trace) do { } while (0) 757 #endif 758 759 __init static int init_irqsoff_tracer(void) 760 { 761 register_irqsoff(irqsoff_tracer); 762 register_preemptoff(preemptoff_tracer); 763 register_preemptirqsoff(preemptirqsoff_tracer); 764 765 return 0; 766 } 767 core_initcall(init_irqsoff_tracer); 768 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */ 769 770 #ifndef CONFIG_IRQSOFF_TRACER 771 static inline void tracer_hardirqs_on(void) { } 772 static inline void tracer_hardirqs_off(void) { } 773 static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { } 774 static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { } 775 #endif 776 777 #ifndef CONFIG_PREEMPT_TRACER 778 static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { } 779 static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { } 780 #endif 781 782 #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING) 783 /* Per-cpu variable to prevent redundant calls when IRQs already off */ 784 static DEFINE_PER_CPU(int, tracing_irq_cpu); 785 786 void trace_hardirqs_on(void) 787 { 788 if (!this_cpu_read(tracing_irq_cpu)) 789 return; 790 791 trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1); 792 tracer_hardirqs_on(); 793 794 this_cpu_write(tracing_irq_cpu, 0); 795 } 796 EXPORT_SYMBOL(trace_hardirqs_on); 797 798 void trace_hardirqs_off(void) 799 { 800 if (this_cpu_read(tracing_irq_cpu)) 801 return; 802 803 this_cpu_write(tracing_irq_cpu, 1); 804 805 trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1); 806 tracer_hardirqs_off(); 807 } 808 EXPORT_SYMBOL(trace_hardirqs_off); 809 810 __visible void trace_hardirqs_on_caller(unsigned long caller_addr) 811 { 812 if (!this_cpu_read(tracing_irq_cpu)) 813 return; 814 815 trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr); 816 tracer_hardirqs_on_caller(caller_addr); 817 818 this_cpu_write(tracing_irq_cpu, 0); 819 } 820 EXPORT_SYMBOL(trace_hardirqs_on_caller); 821 822 __visible void trace_hardirqs_off_caller(unsigned long caller_addr) 823 { 824 if (this_cpu_read(tracing_irq_cpu)) 825 return; 826 827 this_cpu_write(tracing_irq_cpu, 1); 828 829 trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr); 830 tracer_hardirqs_off_caller(caller_addr); 831 } 832 EXPORT_SYMBOL(trace_hardirqs_off_caller); 833 834 /* 835 * Stubs: 836 */ 837 838 void trace_softirqs_on(unsigned long ip) 839 { 840 } 841 842 void trace_softirqs_off(unsigned long ip) 843 { 844 } 845 846 inline void print_irqtrace_events(struct task_struct *curr) 847 { 848 } 849 #endif 850 851 #if defined(CONFIG_PREEMPT_TRACER) || \ 852 (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS)) 853 void trace_preempt_on(unsigned long a0, unsigned long a1) 854 { 855 trace_preempt_enable_rcuidle(a0, a1); 856 tracer_preempt_on(a0, a1); 857 } 858 859 void trace_preempt_off(unsigned long a0, unsigned long a1) 860 { 861 trace_preempt_disable_rcuidle(a0, a1); 862 tracer_preempt_off(a0, a1); 863 } 864 #endif 865