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 (ftrace_graph_ignore_func(trace))
 179                 return 0;
 180         /*
 181          * Do not trace a function if it's filtered by set_graph_notrace.
 182          * Make the index of ret stack negative to indicate that it should
 183          * ignore further functions.  But it needs its own ret stack entry
 184          * to recover the original index in order to continue tracing after
 185          * returning from the function.
 186          */
 187         if (ftrace_graph_notrace_addr(trace->func))
 188                 return 1;
 189
 190         if (!func_prolog_dec(tr, &data, &flags))
 191                 return 0;
 192
 193         pc = preempt_count();
 194         ret = __trace_graph_entry(tr, trace, flags, pc);
 195         atomic_dec(&data->disabled);
 196
 197         return ret;
 198 }
 199
 200 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 201 {
 202         struct trace_array *tr = irqsoff_trace;
 203         struct trace_array_cpu *data;
 204         unsigned long flags;
 205         int pc;
 206
 207         if (!func_prolog_dec(tr, &data, &flags))
 208                 return;
 209
 210         pc = preempt_count();
 211         __trace_graph_return(tr, trace, flags, pc);
 212         atomic_dec(&data->disabled);
 213 }
 214
 215 static void irqsoff_trace_open(struct trace_iterator *iter)
 216 {
 217         if (is_graph(iter->tr))
 218                 graph_trace_open(iter);
 219
 220 }
 221
 222 static void irqsoff_trace_close(struct trace_iterator *iter)
 223 {
 224         if (iter->private)
 225                 graph_trace_close(iter);
 226 }
 227
 228 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 229                             TRACE_GRAPH_PRINT_PROC | \
 230                             TRACE_GRAPH_PRINT_ABS_TIME | \
 231                             TRACE_GRAPH_PRINT_DURATION)
 232
 233 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 234 {
 235         /*
 236          * In graph mode call the graph tracer output function,
 237          * otherwise go with the TRACE_FN event handler
 238          */
 239         if (is_graph(iter->tr))
 240                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 241
 242         return TRACE_TYPE_UNHANDLED;
 243 }
 244
 245 static void irqsoff_print_header(struct seq_file *s)
 246 {
 247         struct trace_array *tr = irqsoff_trace;
 248
 249         if (is_graph(tr))
 250                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 251         else
 252                 trace_default_header(s);
 253 }
 254
 255 static void
 256 __trace_function(struct trace_array *tr,
 257                  unsigned long ip, unsigned long parent_ip,
 258                  unsigned long flags, int pc)
 259 {
 260         if (is_graph(tr))
 261                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 262         else
 263                 trace_function(tr, ip, parent_ip, flags, pc);
 264 }
 265
 266 #else
 267 #define __trace_function trace_function
 268
 269 #ifdef CONFIG_FUNCTION_TRACER
 270 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 271 {
 272         return -1;
 273 }
 274 #endif
 275
 276 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 277 {
 278         return TRACE_TYPE_UNHANDLED;
 279 }
 280
 281 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 282 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 283
 284 #ifdef CONFIG_FUNCTION_TRACER
 285 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 286 static void irqsoff_print_header(struct seq_file *s)
 287 {
 288         trace_default_header(s);
 289 }
 290 #else
 291 static void irqsoff_print_header(struct seq_file *s)
 292 {
 293         trace_latency_header(s);
 294 }
 295 #endif /* CONFIG_FUNCTION_TRACER */
 296 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 297
 298 /*
 299  * Should this new latency be reported/recorded?
 300  */
 301 static bool report_latency(struct trace_array *tr, u64 delta)
 302 {
 303         if (tracing_thresh) {
 304                 if (delta < tracing_thresh)
 305                         return false;
 306         } else {
 307                 if (delta <= tr->max_latency)
 308                         return false;
 309         }
 310         return true;
 311 }
 312
 313 static void
 314 check_critical_timing(struct trace_array *tr,
 315                       struct trace_array_cpu *data,
 316                       unsigned long parent_ip,
 317                       int cpu)
 318 {
 319         u64 T0, T1, delta;
 320         unsigned long flags;
 321         int pc;
 322
 323         T0 = data->preempt_timestamp;
 324         T1 = ftrace_now(cpu);
 325         delta = T1-T0;
 326
 327         local_save_flags(flags);
 328
 329         pc = preempt_count();
 330
 331         if (!report_latency(tr, delta))
 332                 goto out;
 333
 334         raw_spin_lock_irqsave(&max_trace_lock, flags);
 335
 336         /* check if we are still the max latency */
 337         if (!report_latency(tr, delta))
 338                 goto out_unlock;
 339
 340         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 341         /* Skip 5 functions to get to the irq/preempt enable function */
 342         __trace_stack(tr, flags, 5, pc);
 343
 344         if (data->critical_sequence != max_sequence)
 345                 goto out_unlock;
 346
 347         data->critical_end = parent_ip;
 348
 349         if (likely(!is_tracing_stopped())) {
 350                 tr->max_latency = delta;
 351                 update_max_tr_single(tr, current, cpu);
 352         }
 353
 354         max_sequence++;
 355
 356 out_unlock:
 357         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 358
 359 out:
 360         data->critical_sequence = max_sequence;
 361         data->preempt_timestamp = ftrace_now(cpu);
 362         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 363 }
 364
 365 static inline void
 366 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 367 {
 368         int cpu;
 369         struct trace_array *tr = irqsoff_trace;
 370         struct trace_array_cpu *data;
 371         unsigned long flags;
 372
 373         if (!tracer_enabled || !tracing_is_enabled())
 374                 return;
 375
 376         cpu = raw_smp_processor_id();
 377
 378         if (per_cpu(tracing_cpu, cpu))
 379                 return;
 380
 381         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 382
 383         if (unlikely(!data) || atomic_read(&data->disabled))
 384                 return;
 385
 386         atomic_inc(&data->disabled);
 387
 388         data->critical_sequence = max_sequence;
 389         data->preempt_timestamp = ftrace_now(cpu);
 390         data->critical_start = parent_ip ? : ip;
 391
 392         local_save_flags(flags);
 393
 394         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 395
 396         per_cpu(tracing_cpu, cpu) = 1;
 397
 398         atomic_dec(&data->disabled);
 399 }
 400
 401 static inline void
 402 stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 403 {
 404         int cpu;
 405         struct trace_array *tr = irqsoff_trace;
 406         struct trace_array_cpu *data;
 407         unsigned long flags;
 408
 409         cpu = raw_smp_processor_id();
 410         /* Always clear the tracing cpu on stopping the trace */
 411         if (unlikely(per_cpu(tracing_cpu, cpu)))
 412                 per_cpu(tracing_cpu, cpu) = 0;
 413         else
 414                 return;
 415
 416         if (!tracer_enabled || !tracing_is_enabled())
 417                 return;
 418
 419         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 420
 421         if (unlikely(!data) ||
 422             !data->critical_start || atomic_read(&data->disabled))
 423                 return;
 424
 425         atomic_inc(&data->disabled);
 426
 427         local_save_flags(flags);
 428         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 429         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 430         data->critical_start = 0;
 431         atomic_dec(&data->disabled);
 432 }
 433
 434 /* start and stop critical timings used to for stoppage (in idle) */
 435 void start_critical_timings(void)
 436 {
 437         if (preempt_trace() || irq_trace())
 438                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 439 }
 440 EXPORT_SYMBOL_GPL(start_critical_timings);
 441
 442 void stop_critical_timings(void)
 443 {
 444         if (preempt_trace() || irq_trace())
 445                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 446 }
 447 EXPORT_SYMBOL_GPL(stop_critical_timings);
 448
 449 #ifdef CONFIG_IRQSOFF_TRACER
 450 #ifdef CONFIG_PROVE_LOCKING
 451 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 452 {
 453         if (!preempt_trace() && irq_trace())
 454                 stop_critical_timing(a0, a1);
 455 }
 456
 457 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 458 {
 459         if (!preempt_trace() && irq_trace())
 460                 start_critical_timing(a0, a1);
 461 }
 462
 463 #else /* !CONFIG_PROVE_LOCKING */
 464
 465 /*
 466  * Stubs:
 467  */
 468
 469 void trace_softirqs_on(unsigned long ip)
 470 {
 471 }
 472
 473 void trace_softirqs_off(unsigned long ip)
 474 {
 475 }
 476
 477 inline void print_irqtrace_events(struct task_struct *curr)
 478 {
 479 }
 480
 481 /*
 482  * We are only interested in hardirq on/off events:
 483  */
 484 void trace_hardirqs_on(void)
 485 {
 486         if (!preempt_trace() && irq_trace())
 487                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 488 }
 489 EXPORT_SYMBOL(trace_hardirqs_on);
 490
 491 void trace_hardirqs_off(void)
 492 {
 493         if (!preempt_trace() && irq_trace())
 494                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 495 }
 496 EXPORT_SYMBOL(trace_hardirqs_off);
 497
 498 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 499 {
 500         if (!preempt_trace() && irq_trace())
 501                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 502 }
 503 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 504
 505 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 506 {
 507         if (!preempt_trace() && irq_trace())
 508                 start_critical_timing(CALLER_ADDR0, caller_addr);
 509 }
 510 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 511
 512 #endif /* CONFIG_PROVE_LOCKING */
 513 #endif /*  CONFIG_IRQSOFF_TRACER */
 514
 515 #ifdef CONFIG_PREEMPT_TRACER
 516 void trace_preempt_on(unsigned long a0, unsigned long a1)
 517 {
 518         if (preempt_trace() && !irq_trace())
 519                 stop_critical_timing(a0, a1);
 520 }
 521
 522 void trace_preempt_off(unsigned long a0, unsigned long a1)
 523 {
 524         if (preempt_trace() && !irq_trace())
 525                 start_critical_timing(a0, a1);
 526 }
 527 #endif /* CONFIG_PREEMPT_TRACER */
 528
 529 #ifdef CONFIG_FUNCTION_TRACER
 530 static bool function_enabled;
 531
 532 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 533 {
 534         int ret;
 535
 536         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 537         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 538                 return 0;
 539
 540         if (graph)
 541                 ret = register_ftrace_graph(&irqsoff_graph_return,
 542                                             &irqsoff_graph_entry);
 543         else
 544                 ret = register_ftrace_function(tr->ops);
 545
 546         if (!ret)
 547                 function_enabled = true;
 548
 549         return ret;
 550 }
 551
 552 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 553 {
 554         if (!function_enabled)
 555                 return;
 556
 557         if (graph)
 558                 unregister_ftrace_graph();
 559         else
 560                 unregister_ftrace_function(tr->ops);
 561
 562         function_enabled = false;
 563 }
 564
 565 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 566 {
 567         if (!(mask & TRACE_ITER_FUNCTION))
 568                 return 0;
 569
 570         if (set)
 571                 register_irqsoff_function(tr, is_graph(tr), 1);
 572         else
 573                 unregister_irqsoff_function(tr, is_graph(tr));
 574         return 1;
 575 }
 576 #else
 577 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 578 {
 579         return 0;
 580 }
 581 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 582 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 583 {
 584         return 0;
 585 }
 586 #endif /* CONFIG_FUNCTION_TRACER */
 587
 588 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 589 {
 590         struct tracer *tracer = tr->current_trace;
 591
 592         if (irqsoff_function_set(tr, mask, set))
 593                 return 0;
 594
 595 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 596         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 597                 return irqsoff_display_graph(tr, set);
 598 #endif
 599
 600         return trace_keep_overwrite(tracer, mask, set);
 601 }
 602
 603 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 604 {
 605         int ret;
 606
 607         ret = register_irqsoff_function(tr, graph, 0);
 608
 609         if (!ret && tracing_is_enabled())
 610                 tracer_enabled = 1;
 611         else
 612                 tracer_enabled = 0;
 613
 614         return ret;
 615 }
 616
 617 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 618 {
 619         tracer_enabled = 0;
 620
 621         unregister_irqsoff_function(tr, graph);
 622 }
 623
 624 static bool irqsoff_busy;
 625
 626 static int __irqsoff_tracer_init(struct trace_array *tr)
 627 {
 628         if (irqsoff_busy)
 629                 return -EBUSY;
 630
 631         save_flags = tr->trace_flags;
 632
 633         /* non overwrite screws up the latency tracers */
 634         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 635         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 636
 637         tr->max_latency = 0;
 638         irqsoff_trace = tr;
 639         /* make sure that the tracer is visible */
 640         smp_wmb();
 641
 642         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 643
 644         /* Only toplevel instance supports graph tracing */
 645         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 646                                       is_graph(tr))))
 647                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 648
 649         irqsoff_busy = true;
 650         return 0;
 651 }
 652
 653 static void irqsoff_tracer_reset(struct trace_array *tr)
 654 {
 655         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 656         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 657
 658         stop_irqsoff_tracer(tr, is_graph(tr));
 659
 660         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 661         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 662         ftrace_reset_array_ops(tr);
 663
 664         irqsoff_busy = false;
 665 }
 666
 667 static void irqsoff_tracer_start(struct trace_array *tr)
 668 {
 669         tracer_enabled = 1;
 670 }
 671
 672 static void irqsoff_tracer_stop(struct trace_array *tr)
 673 {
 674         tracer_enabled = 0;
 675 }
 676
 677 #ifdef CONFIG_IRQSOFF_TRACER
 678 static int irqsoff_tracer_init(struct trace_array *tr)
 679 {
 680         trace_type = TRACER_IRQS_OFF;
 681
 682         return __irqsoff_tracer_init(tr);
 683 }
 684 static struct tracer irqsoff_tracer __read_mostly =
 685 {
 686         .name           = "irqsoff",
 687         .init           = irqsoff_tracer_init,
 688         .reset          = irqsoff_tracer_reset,
 689         .start          = irqsoff_tracer_start,
 690         .stop           = irqsoff_tracer_stop,
 691         .print_max      = true,
 692         .print_header   = irqsoff_print_header,
 693         .print_line     = irqsoff_print_line,
 694         .flag_changed   = irqsoff_flag_changed,
 695 #ifdef CONFIG_FTRACE_SELFTEST
 696         .selftest    = trace_selftest_startup_irqsoff,
 697 #endif
 698         .open           = irqsoff_trace_open,
 699         .close          = irqsoff_trace_close,
 700         .allow_instances = true,
 701         .use_max_tr     = true,
 702 };
 703 # define register_irqsoff(trace) register_tracer(&trace)
 704 #else
 705 # define register_irqsoff(trace) do { } while (0)
 706 #endif
 707
 708 #ifdef CONFIG_PREEMPT_TRACER
 709 static int preemptoff_tracer_init(struct trace_array *tr)
 710 {
 711         trace_type = TRACER_PREEMPT_OFF;
 712
 713         return __irqsoff_tracer_init(tr);
 714 }
 715
 716 static struct tracer preemptoff_tracer __read_mostly =
 717 {
 718         .name           = "preemptoff",
 719         .init           = preemptoff_tracer_init,
 720         .reset          = irqsoff_tracer_reset,
 721         .start          = irqsoff_tracer_start,
 722         .stop           = irqsoff_tracer_stop,
 723         .print_max      = true,
 724         .print_header   = irqsoff_print_header,
 725         .print_line     = irqsoff_print_line,
 726         .flag_changed   = irqsoff_flag_changed,
 727 #ifdef CONFIG_FTRACE_SELFTEST
 728         .selftest    = trace_selftest_startup_preemptoff,
 729 #endif
 730         .open           = irqsoff_trace_open,
 731         .close          = irqsoff_trace_close,
 732         .allow_instances = true,
 733         .use_max_tr     = true,
 734 };
 735 # define register_preemptoff(trace) register_tracer(&trace)
 736 #else
 737 # define register_preemptoff(trace) do { } while (0)
 738 #endif
 739
 740 #if defined(CONFIG_IRQSOFF_TRACER) && \
 741         defined(CONFIG_PREEMPT_TRACER)
 742
 743 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 744 {
 745         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 746
 747         return __irqsoff_tracer_init(tr);
 748 }
 749
 750 static struct tracer preemptirqsoff_tracer __read_mostly =
 751 {
 752         .name           = "preemptirqsoff",
 753         .init           = preemptirqsoff_tracer_init,
 754         .reset          = irqsoff_tracer_reset,
 755         .start          = irqsoff_tracer_start,
 756         .stop           = irqsoff_tracer_stop,
 757         .print_max      = true,
 758         .print_header   = irqsoff_print_header,
 759         .print_line     = irqsoff_print_line,
 760         .flag_changed   = irqsoff_flag_changed,
 761 #ifdef CONFIG_FTRACE_SELFTEST
 762         .selftest    = trace_selftest_startup_preemptirqsoff,
 763 #endif
 764         .open           = irqsoff_trace_open,
 765         .close          = irqsoff_trace_close,
 766         .allow_instances = true,
 767         .use_max_tr     = true,
 768 };
 769
 770 # define register_preemptirqsoff(trace) register_tracer(&trace)
 771 #else
 772 # define register_preemptirqsoff(trace) do { } while (0)
 773 #endif
 774
 775 __init static int init_irqsoff_tracer(void)
 776 {
 777         register_irqsoff(irqsoff_tracer);
 778         register_preemptoff(preemptoff_tracer);
 779         register_preemptirqsoff(preemptirqsoff_tracer);
 780
 781         return 0;
 782 }
 783 core_initcall(init_irqsoff_tracer);