kernel/trace/trace_irqsoff.c

   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 static struct trace_array               *irqsoff_trace __read_mostly;
  20 static int                              tracer_enabled __read_mostly;
  21
  22 static DEFINE_PER_CPU(int, tracing_cpu);
  23
  24 static DEFINE_RAW_SPINLOCK(max_trace_lock);
  25
  26 enum {
  27         TRACER_IRQS_OFF         = (1 << 1),
  28         TRACER_PREEMPT_OFF      = (1 << 2),
  29 };
  30
  31 static int trace_type __read_mostly;
  32
  33 static int save_flags;
  34
  35 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
  36 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
  37
  38 #ifdef CONFIG_PREEMPT_TRACER
  39 static inline int
  40 preempt_trace(void)
  41 {
  42         return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
  43 }
  44 #else
  45 # define preempt_trace() (0)
  46 #endif
  47
  48 #ifdef CONFIG_IRQSOFF_TRACER
  49 static inline int
  50 irq_trace(void)
  51 {
  52         return ((trace_type & TRACER_IRQS_OFF) &&
  53                 irqs_disabled());
  54 }
  55 #else
  56 # define irq_trace() (0)
  57 #endif
  58
  59 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  60 static int irqsoff_display_graph(struct trace_array *tr, int set);
  61 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
  62 #else
  63 static inline int irqsoff_display_graph(struct trace_array *tr, int set)
  64 {
  65         return -EINVAL;
  66 }
  67 # define is_graph(tr) false
  68 #endif
  69
  70 /*
  71  * Sequence count - we record it when starting a measurement and
  72  * skip the latency if the sequence has changed - some other section
  73  * did a maximum and could disturb our measurement with serial console
  74  * printouts, etc. Truly coinciding maximum latencies should be rare
  75  * and what happens together happens separately as well, so this doesn't
  76  * decrease the validity of the maximum found:
  77  */
  78 static __cacheline_aligned_in_smp       unsigned long max_sequence;
  79
  80 #ifdef CONFIG_FUNCTION_TRACER
  81 /*
  82  * Prologue for the preempt and irqs off function tracers.
  83  *
  84  * Returns 1 if it is OK to continue, and data->disabled is
  85  *            incremented.
  86  *         0 if the trace is to be ignored, and data->disabled
  87  *            is kept the same.
  88  *
  89  * Note, this function is also used outside this ifdef but
  90  *  inside the #ifdef of the function graph tracer below.
  91  *  This is OK, since the function graph tracer is
  92  *  dependent on the function tracer.
  93  */
  94 static int func_prolog_dec(struct trace_array *tr,
  95                            struct trace_array_cpu **data,
  96                            unsigned long *flags)
  97 {
  98         long disabled;
  99         int cpu;
 100
 101         /*
 102          * Does not matter if we preempt. We test the flags
 103          * afterward, to see if irqs are disabled or not.
 104          * If we preempt and get a false positive, the flags
 105          * test will fail.
 106          */
 107         cpu = raw_smp_processor_id();
 108         if (likely(!per_cpu(tracing_cpu, cpu)))
 109                 return 0;
 110
 111         local_save_flags(*flags);
 112         /*
 113          * Slight chance to get a false positive on tracing_cpu,
 114          * although I'm starting to think there isn't a chance.
 115          * Leave this for now just to be paranoid.
 116          */
 117         if (!irqs_disabled_flags(*flags) && !preempt_count())
 118                 return 0;
 119
 120         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 121         disabled = atomic_inc_return(&(*data)->disabled);
 122
 123         if (likely(disabled == 1))
 124                 return 1;
 125
 126         atomic_dec(&(*data)->disabled);
 127
 128         return 0;
 129 }
 130
 131 /*
 132  * irqsoff uses its own tracer function to keep the overhead down:
 133  */
 134 static void
 135 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
 136                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 137 {
 138         struct trace_array *tr = irqsoff_trace;
 139         struct trace_array_cpu *data;
 140         unsigned long flags;
 141
 142         if (!func_prolog_dec(tr, &data, &flags))
 143                 return;
 144
 145         trace_function(tr, ip, parent_ip, flags, preempt_count());
 146
 147         atomic_dec(&data->disabled);
 148 }
 149 #endif /* CONFIG_FUNCTION_TRACER */
 150
 151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 152 static int irqsoff_display_graph(struct trace_array *tr, int set)
 153 {
 154         int cpu;
 155
 156         if (!(is_graph(tr) ^ set))
 157                 return 0;
 158
 159         stop_irqsoff_tracer(irqsoff_trace, !set);
 160
 161         for_each_possible_cpu(cpu)
 162                 per_cpu(tracing_cpu, cpu) = 0;
 163
 164         tr->max_latency = 0;
 165         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 166
 167         return start_irqsoff_tracer(irqsoff_trace, set);
 168 }
 169
 170 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 171 {
 172         struct trace_array *tr = irqsoff_trace;
 173         struct trace_array_cpu *data;
 174         unsigned long flags;
 175         int ret;
 176         int pc;
 177
 178         if (!func_prolog_dec(tr, &data, &flags))
 179                 return 0;
 180
 181         pc = preempt_count();
 182         ret = __trace_graph_entry(tr, trace, flags, pc);
 183         atomic_dec(&data->disabled);
 184
 185         return ret;
 186 }
 187
 188 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 189 {
 190         struct trace_array *tr = irqsoff_trace;
 191         struct trace_array_cpu *data;
 192         unsigned long flags;
 193         int pc;
 194
 195         if (!func_prolog_dec(tr, &data, &flags))
 196                 return;
 197
 198         pc = preempt_count();
 199         __trace_graph_return(tr, trace, flags, pc);
 200         atomic_dec(&data->disabled);
 201 }
 202
 203 static void irqsoff_trace_open(struct trace_iterator *iter)
 204 {
 205         if (is_graph(iter->tr))
 206                 graph_trace_open(iter);
 207
 208 }
 209
 210 static void irqsoff_trace_close(struct trace_iterator *iter)
 211 {
 212         if (iter->private)
 213                 graph_trace_close(iter);
 214 }
 215
 216 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 217                             TRACE_GRAPH_PRINT_PROC | \
 218                             TRACE_GRAPH_PRINT_ABS_TIME | \
 219                             TRACE_GRAPH_PRINT_DURATION)
 220
 221 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 222 {
 223         /*
 224          * In graph mode call the graph tracer output function,
 225          * otherwise go with the TRACE_FN event handler
 226          */
 227         if (is_graph(iter->tr))
 228                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 229
 230         return TRACE_TYPE_UNHANDLED;
 231 }
 232
 233 static void irqsoff_print_header(struct seq_file *s)
 234 {
 235         struct trace_array *tr = irqsoff_trace;
 236
 237         if (is_graph(tr))
 238                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 239         else
 240                 trace_default_header(s);
 241 }
 242
 243 static void
 244 __trace_function(struct trace_array *tr,
 245                  unsigned long ip, unsigned long parent_ip,
 246                  unsigned long flags, int pc)
 247 {
 248         if (is_graph(tr))
 249                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 250         else
 251                 trace_function(tr, ip, parent_ip, flags, pc);
 252 }
 253
 254 #else
 255 #define __trace_function trace_function
 256
 257 #ifdef CONFIG_FUNCTION_TRACER
 258 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 259 {
 260         return -1;
 261 }
 262 #endif
 263
 264 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 265 {
 266         return TRACE_TYPE_UNHANDLED;
 267 }
 268
 269 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 270 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 271
 272 #ifdef CONFIG_FUNCTION_TRACER
 273 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 274 static void irqsoff_print_header(struct seq_file *s)
 275 {
 276         trace_default_header(s);
 277 }
 278 #else
 279 static void irqsoff_print_header(struct seq_file *s)
 280 {
 281         trace_latency_header(s);
 282 }
 283 #endif /* CONFIG_FUNCTION_TRACER */
 284 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 285
 286 /*
 287  * Should this new latency be reported/recorded?
 288  */
 289 static bool report_latency(struct trace_array *tr, cycle_t delta)
 290 {
 291         if (tracing_thresh) {
 292                 if (delta < tracing_thresh)
 293                         return false;
 294         } else {
 295                 if (delta <= tr->max_latency)
 296                         return false;
 297         }
 298         return true;
 299 }
 300
 301 static void
 302 check_critical_timing(struct trace_array *tr,
 303                       struct trace_array_cpu *data,
 304                       unsigned long parent_ip,
 305                       int cpu)
 306 {
 307         cycle_t T0, T1, delta;
 308         unsigned long flags;
 309         int pc;
 310
 311         T0 = data->preempt_timestamp;
 312         T1 = ftrace_now(cpu);
 313         delta = T1-T0;
 314
 315         local_save_flags(flags);
 316
 317         pc = preempt_count();
 318
 319         if (!report_latency(tr, delta))
 320                 goto out;
 321
 322         raw_spin_lock_irqsave(&max_trace_lock, flags);
 323
 324         /* check if we are still the max latency */
 325         if (!report_latency(tr, delta))
 326                 goto out_unlock;
 327
 328         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 329         /* Skip 5 functions to get to the irq/preempt enable function */
 330         __trace_stack(tr, flags, 5, pc);
 331
 332         if (data->critical_sequence != max_sequence)
 333                 goto out_unlock;
 334
 335         data->critical_end = parent_ip;
 336
 337         if (likely(!is_tracing_stopped())) {
 338                 tr->max_latency = delta;
 339                 update_max_tr_single(tr, current, cpu);
 340         }
 341
 342         max_sequence++;
 343
 344 out_unlock:
 345         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 346
 347 out:
 348         data->critical_sequence = max_sequence;
 349         data->preempt_timestamp = ftrace_now(cpu);
 350         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 351 }
 352
 353 static inline void
 354 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 355 {
 356         int cpu;
 357         struct trace_array *tr = irqsoff_trace;
 358         struct trace_array_cpu *data;
 359         unsigned long flags;
 360
 361         if (!tracer_enabled || !tracing_is_enabled())
 362                 return;
 363
 364         cpu = raw_smp_processor_id();
 365
 366         if (per_cpu(tracing_cpu, cpu))
 367                 return;
 368
 369         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 370
 371         if (unlikely(!data) || atomic_read(&data->disabled))
 372                 return;
 373
 374         atomic_inc(&data->disabled);
 375
 376         data->critical_sequence = max_sequence;
 377         data->preempt_timestamp = ftrace_now(cpu);
 378         data->critical_start = parent_ip ? : ip;
 379
 380         local_save_flags(flags);
 381
 382         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 383
 384         per_cpu(tracing_cpu, cpu) = 1;
 385
 386         atomic_dec(&data->disabled);
 387 }
 388
 389 static inline void
 390 stop_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         unsigned long flags;
 396
 397         cpu = raw_smp_processor_id();
 398         /* Always clear the tracing cpu on stopping the trace */
 399         if (unlikely(per_cpu(tracing_cpu, cpu)))
 400                 per_cpu(tracing_cpu, cpu) = 0;
 401         else
 402                 return;
 403
 404         if (!tracer_enabled || !tracing_is_enabled())
 405                 return;
 406
 407         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 408
 409         if (unlikely(!data) ||
 410             !data->critical_start || atomic_read(&data->disabled))
 411                 return;
 412
 413         atomic_inc(&data->disabled);
 414
 415         local_save_flags(flags);
 416         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 417         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 418         data->critical_start = 0;
 419         atomic_dec(&data->disabled);
 420 }
 421
 422 /* start and stop critical timings used to for stoppage (in idle) */
 423 void start_critical_timings(void)
 424 {
 425         if (preempt_trace() || irq_trace())
 426                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 427 }
 428 EXPORT_SYMBOL_GPL(start_critical_timings);
 429
 430 void stop_critical_timings(void)
 431 {
 432         if (preempt_trace() || irq_trace())
 433                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 434 }
 435 EXPORT_SYMBOL_GPL(stop_critical_timings);
 436
 437 #ifdef CONFIG_IRQSOFF_TRACER
 438 #ifdef CONFIG_PROVE_LOCKING
 439 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 440 {
 441         if (!preempt_trace() && irq_trace())
 442                 stop_critical_timing(a0, a1);
 443 }
 444
 445 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 446 {
 447         if (!preempt_trace() && irq_trace())
 448                 start_critical_timing(a0, a1);
 449 }
 450
 451 #else /* !CONFIG_PROVE_LOCKING */
 452
 453 /*
 454  * Stubs:
 455  */
 456
 457 void trace_softirqs_on(unsigned long ip)
 458 {
 459 }
 460
 461 void trace_softirqs_off(unsigned long ip)
 462 {
 463 }
 464
 465 inline void print_irqtrace_events(struct task_struct *curr)
 466 {
 467 }
 468
 469 /*
 470  * We are only interested in hardirq on/off events:
 471  */
 472 void trace_hardirqs_on(void)
 473 {
 474         if (!preempt_trace() && irq_trace())
 475                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 476 }
 477 EXPORT_SYMBOL(trace_hardirqs_on);
 478
 479 void trace_hardirqs_off(void)
 480 {
 481         if (!preempt_trace() && irq_trace())
 482                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 483 }
 484 EXPORT_SYMBOL(trace_hardirqs_off);
 485
 486 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 487 {
 488         if (!preempt_trace() && irq_trace())
 489                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 490 }
 491 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 492
 493 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 494 {
 495         if (!preempt_trace() && irq_trace())
 496                 start_critical_timing(CALLER_ADDR0, caller_addr);
 497 }
 498 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 499
 500 #endif /* CONFIG_PROVE_LOCKING */
 501 #endif /*  CONFIG_IRQSOFF_TRACER */
 502
 503 #ifdef CONFIG_PREEMPT_TRACER
 504 void trace_preempt_on(unsigned long a0, unsigned long a1)
 505 {
 506         if (preempt_trace() && !irq_trace())
 507                 stop_critical_timing(a0, a1);
 508 }
 509
 510 void trace_preempt_off(unsigned long a0, unsigned long a1)
 511 {
 512         if (preempt_trace() && !irq_trace())
 513                 start_critical_timing(a0, a1);
 514 }
 515 #endif /* CONFIG_PREEMPT_TRACER */
 516
 517 #ifdef CONFIG_FUNCTION_TRACER
 518 static bool function_enabled;
 519
 520 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 521 {
 522         int ret;
 523
 524         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 525         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 526                 return 0;
 527
 528         if (graph)
 529                 ret = register_ftrace_graph(&irqsoff_graph_return,
 530                                             &irqsoff_graph_entry);
 531         else
 532                 ret = register_ftrace_function(tr->ops);
 533
 534         if (!ret)
 535                 function_enabled = true;
 536
 537         return ret;
 538 }
 539
 540 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 541 {
 542         if (!function_enabled)
 543                 return;
 544
 545         if (graph)
 546                 unregister_ftrace_graph();
 547         else
 548                 unregister_ftrace_function(tr->ops);
 549
 550         function_enabled = false;
 551 }
 552
 553 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 554 {
 555         if (!(mask & TRACE_ITER_FUNCTION))
 556                 return 0;
 557
 558         if (set)
 559                 register_irqsoff_function(tr, is_graph(tr), 1);
 560         else
 561                 unregister_irqsoff_function(tr, is_graph(tr));
 562         return 1;
 563 }
 564 #else
 565 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 566 {
 567         return 0;
 568 }
 569 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 570 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 571 {
 572         return 0;
 573 }
 574 #endif /* CONFIG_FUNCTION_TRACER */
 575
 576 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 577 {
 578         struct tracer *tracer = tr->current_trace;
 579
 580         if (irqsoff_function_set(tr, mask, set))
 581                 return 0;
 582
 583 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 584         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 585                 return irqsoff_display_graph(tr, set);
 586 #endif
 587
 588         return trace_keep_overwrite(tracer, mask, set);
 589 }
 590
 591 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 592 {
 593         int ret;
 594
 595         ret = register_irqsoff_function(tr, graph, 0);
 596
 597         if (!ret && tracing_is_enabled())
 598                 tracer_enabled = 1;
 599         else
 600                 tracer_enabled = 0;
 601
 602         return ret;
 603 }
 604
 605 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 606 {
 607         tracer_enabled = 0;
 608
 609         unregister_irqsoff_function(tr, graph);
 610 }
 611
 612 static bool irqsoff_busy;
 613
 614 static int __irqsoff_tracer_init(struct trace_array *tr)
 615 {
 616         if (irqsoff_busy)
 617                 return -EBUSY;
 618
 619         save_flags = tr->trace_flags;
 620
 621         /* non overwrite screws up the latency tracers */
 622         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 623         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 624
 625         tr->max_latency = 0;
 626         irqsoff_trace = tr;
 627         /* make sure that the tracer is visible */
 628         smp_wmb();
 629         tracing_reset_online_cpus(&tr->trace_buffer);
 630
 631         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 632
 633         /* Only toplevel instance supports graph tracing */
 634         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 635                                       is_graph(tr))))
 636                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 637
 638         irqsoff_busy = true;
 639         return 0;
 640 }
 641
 642 static void irqsoff_tracer_reset(struct trace_array *tr)
 643 {
 644         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 645         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 646
 647         stop_irqsoff_tracer(tr, is_graph(tr));
 648
 649         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 650         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 651         ftrace_reset_array_ops(tr);
 652
 653         irqsoff_busy = false;
 654 }
 655
 656 static void irqsoff_tracer_start(struct trace_array *tr)
 657 {
 658         tracer_enabled = 1;
 659 }
 660
 661 static void irqsoff_tracer_stop(struct trace_array *tr)
 662 {
 663         tracer_enabled = 0;
 664 }
 665
 666 #ifdef CONFIG_IRQSOFF_TRACER
 667 static int irqsoff_tracer_init(struct trace_array *tr)
 668 {
 669         trace_type = TRACER_IRQS_OFF;
 670
 671         return __irqsoff_tracer_init(tr);
 672 }
 673 static struct tracer irqsoff_tracer __read_mostly =
 674 {
 675         .name           = "irqsoff",
 676         .init           = irqsoff_tracer_init,
 677         .reset          = irqsoff_tracer_reset,
 678         .start          = irqsoff_tracer_start,
 679         .stop           = irqsoff_tracer_stop,
 680         .print_max      = true,
 681         .print_header   = irqsoff_print_header,
 682         .print_line     = irqsoff_print_line,
 683         .flag_changed   = irqsoff_flag_changed,
 684 #ifdef CONFIG_FTRACE_SELFTEST
 685         .selftest    = trace_selftest_startup_irqsoff,
 686 #endif
 687         .open           = irqsoff_trace_open,
 688         .close          = irqsoff_trace_close,
 689         .allow_instances = true,
 690         .use_max_tr     = true,
 691 };
 692 # define register_irqsoff(trace) register_tracer(&trace)
 693 #else
 694 # define register_irqsoff(trace) do { } while (0)
 695 #endif
 696
 697 #ifdef CONFIG_PREEMPT_TRACER
 698 static int preemptoff_tracer_init(struct trace_array *tr)
 699 {
 700         trace_type = TRACER_PREEMPT_OFF;
 701
 702         return __irqsoff_tracer_init(tr);
 703 }
 704
 705 static struct tracer preemptoff_tracer __read_mostly =
 706 {
 707         .name           = "preemptoff",
 708         .init           = preemptoff_tracer_init,
 709         .reset          = irqsoff_tracer_reset,
 710         .start          = irqsoff_tracer_start,
 711         .stop           = irqsoff_tracer_stop,
 712         .print_max      = true,
 713         .print_header   = irqsoff_print_header,
 714         .print_line     = irqsoff_print_line,
 715         .flag_changed   = irqsoff_flag_changed,
 716 #ifdef CONFIG_FTRACE_SELFTEST
 717         .selftest    = trace_selftest_startup_preemptoff,
 718 #endif
 719         .open           = irqsoff_trace_open,
 720         .close          = irqsoff_trace_close,
 721         .allow_instances = true,
 722         .use_max_tr     = true,
 723 };
 724 # define register_preemptoff(trace) register_tracer(&trace)
 725 #else
 726 # define register_preemptoff(trace) do { } while (0)
 727 #endif
 728
 729 #if defined(CONFIG_IRQSOFF_TRACER) && \
 730         defined(CONFIG_PREEMPT_TRACER)
 731
 732 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 733 {
 734         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 735
 736         return __irqsoff_tracer_init(tr);
 737 }
 738
 739 static struct tracer preemptirqsoff_tracer __read_mostly =
 740 {
 741         .name           = "preemptirqsoff",
 742         .init           = preemptirqsoff_tracer_init,
 743         .reset          = irqsoff_tracer_reset,
 744         .start          = irqsoff_tracer_start,
 745         .stop           = irqsoff_tracer_stop,
 746         .print_max      = true,
 747         .print_header   = irqsoff_print_header,
 748         .print_line     = irqsoff_print_line,
 749         .flag_changed   = irqsoff_flag_changed,
 750 #ifdef CONFIG_FTRACE_SELFTEST
 751         .selftest    = trace_selftest_startup_preemptirqsoff,
 752 #endif
 753         .open           = irqsoff_trace_open,
 754         .close          = irqsoff_trace_close,
 755         .allow_instances = true,
 756         .use_max_tr     = true,
 757 };
 758
 759 # define register_preemptirqsoff(trace) register_tracer(&trace)
 760 #else
 761 # define register_preemptirqsoff(trace) do { } while (0)
 762 #endif
 763
 764 __init static int init_irqsoff_tracer(void)
 765 {
 766         register_irqsoff(irqsoff_tracer);
 767         register_preemptoff(preemptoff_tracer);
 768         register_preemptirqsoff(preemptirqsoff_tracer);
 769
 770         return 0;
 771 }
 772 core_initcall(init_irqsoff_tracer);