kernel/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 #include <trace/events/hist.h>
  17
  18 #include "trace.h"
  19
  20 static struct trace_array               *irqsoff_trace __read_mostly;
  21 static int                              tracer_enabled __read_mostly;
  22
  23 static DEFINE_PER_CPU(int, tracing_cpu);
  24
  25 static DEFINE_RAW_SPINLOCK(max_trace_lock);
  26
  27 enum {
  28         TRACER_IRQS_OFF         = (1 << 1),
  29         TRACER_PREEMPT_OFF      = (1 << 2),
  30 };
  31
  32 static int trace_type __read_mostly;
  33
  34 static int save_flags;
  35
  36 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
  37 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
  38
  39 #ifdef CONFIG_PREEMPT_TRACER
  40 static inline int
  41 preempt_trace(void)
  42 {
  43         return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
  44 }
  45 #else
  46 # define preempt_trace() (0)
  47 #endif
  48
  49 #ifdef CONFIG_IRQSOFF_TRACER
  50 static inline int
  51 irq_trace(void)
  52 {
  53         return ((trace_type & TRACER_IRQS_OFF) &&
  54                 irqs_disabled());
  55 }
  56 #else
  57 # define irq_trace() (0)
  58 #endif
  59
  60 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  61 static int irqsoff_display_graph(struct trace_array *tr, int set);
  62 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
  63 #else
  64 static inline int irqsoff_display_graph(struct trace_array *tr, int set)
  65 {
  66         return -EINVAL;
  67 }
  68 # define is_graph(tr) false
  69 #endif
  70
  71 /*
  72  * Sequence count - we record it when starting a measurement and
  73  * skip the latency if the sequence has changed - some other section
  74  * did a maximum and could disturb our measurement with serial console
  75  * printouts, etc. Truly coinciding maximum latencies should be rare
  76  * and what happens together happens separately as well, so this doesn't
  77  * decrease the validity of the maximum found:
  78  */
  79 static __cacheline_aligned_in_smp       unsigned long max_sequence;
  80
  81 #ifdef CONFIG_FUNCTION_TRACER
  82 /*
  83  * Prologue for the preempt and irqs off function tracers.
  84  *
  85  * Returns 1 if it is OK to continue, and data->disabled is
  86  *            incremented.
  87  *         0 if the trace is to be ignored, and data->disabled
  88  *            is kept the same.
  89  *
  90  * Note, this function is also used outside this ifdef but
  91  *  inside the #ifdef of the function graph tracer below.
  92  *  This is OK, since the function graph tracer is
  93  *  dependent on the function tracer.
  94  */
  95 static int func_prolog_dec(struct trace_array *tr,
  96                            struct trace_array_cpu **data,
  97                            unsigned long *flags)
  98 {
  99         long disabled;
 100         int cpu;
 101
 102         /*
 103          * Does not matter if we preempt. We test the flags
 104          * afterward, to see if irqs are disabled or not.
 105          * If we preempt and get a false positive, the flags
 106          * test will fail.
 107          */
 108         cpu = raw_smp_processor_id();
 109         if (likely(!per_cpu(tracing_cpu, cpu)))
 110                 return 0;
 111
 112         local_save_flags(*flags);
 113         /*
 114          * Slight chance to get a false positive on tracing_cpu,
 115          * although I'm starting to think there isn't a chance.
 116          * Leave this for now just to be paranoid.
 117          */
 118         if (!irqs_disabled_flags(*flags) && !preempt_count())
 119                 return 0;
 120
 121         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 122         disabled = atomic_inc_return(&(*data)->disabled);
 123
 124         if (likely(disabled == 1))
 125                 return 1;
 126
 127         atomic_dec(&(*data)->disabled);
 128
 129         return 0;
 130 }
 131
 132 /*
 133  * irqsoff uses its own tracer function to keep the overhead down:
 134  */
 135 static void
 136 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
 137                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 138 {
 139         struct trace_array *tr = irqsoff_trace;
 140         struct trace_array_cpu *data;
 141         unsigned long flags;
 142
 143         if (!func_prolog_dec(tr, &data, &flags))
 144                 return;
 145
 146         trace_function(tr, ip, parent_ip, flags, preempt_count());
 147
 148         atomic_dec(&data->disabled);
 149 }
 150 #endif /* CONFIG_FUNCTION_TRACER */
 151
 152 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 153 static int irqsoff_display_graph(struct trace_array *tr, int set)
 154 {
 155         int cpu;
 156
 157         if (!(is_graph(tr) ^ set))
 158                 return 0;
 159
 160         stop_irqsoff_tracer(irqsoff_trace, !set);
 161
 162         for_each_possible_cpu(cpu)
 163                 per_cpu(tracing_cpu, cpu) = 0;
 164
 165         tr->max_latency = 0;
 166         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 167
 168         return start_irqsoff_tracer(irqsoff_trace, set);
 169 }
 170
 171 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 172 {
 173         struct trace_array *tr = irqsoff_trace;
 174         struct trace_array_cpu *data;
 175         unsigned long flags;
 176         int ret;
 177         int pc;
 178
 179         if (!func_prolog_dec(tr, &data, &flags))
 180                 return 0;
 181
 182         pc = preempt_count();
 183         ret = __trace_graph_entry(tr, trace, flags, pc);
 184         atomic_dec(&data->disabled);
 185
 186         return ret;
 187 }
 188
 189 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 190 {
 191         struct trace_array *tr = irqsoff_trace;
 192         struct trace_array_cpu *data;
 193         unsigned long flags;
 194         int pc;
 195
 196         if (!func_prolog_dec(tr, &data, &flags))
 197                 return;
 198
 199         pc = preempt_count();
 200         __trace_graph_return(tr, trace, flags, pc);
 201         atomic_dec(&data->disabled);
 202 }
 203
 204 static void irqsoff_trace_open(struct trace_iterator *iter)
 205 {
 206         if (is_graph(iter->tr))
 207                 graph_trace_open(iter);
 208
 209 }
 210
 211 static void irqsoff_trace_close(struct trace_iterator *iter)
 212 {
 213         if (iter->private)
 214                 graph_trace_close(iter);
 215 }
 216
 217 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 218                             TRACE_GRAPH_PRINT_PROC | \
 219                             TRACE_GRAPH_PRINT_ABS_TIME | \
 220                             TRACE_GRAPH_PRINT_DURATION)
 221
 222 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 223 {
 224         /*
 225          * In graph mode call the graph tracer output function,
 226          * otherwise go with the TRACE_FN event handler
 227          */
 228         if (is_graph(iter->tr))
 229                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 230
 231         return TRACE_TYPE_UNHANDLED;
 232 }
 233
 234 static void irqsoff_print_header(struct seq_file *s)
 235 {
 236         struct trace_array *tr = irqsoff_trace;
 237
 238         if (is_graph(tr))
 239                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 240         else
 241                 trace_default_header(s);
 242 }
 243
 244 static void
 245 __trace_function(struct trace_array *tr,
 246                  unsigned long ip, unsigned long parent_ip,
 247                  unsigned long flags, int pc)
 248 {
 249         if (is_graph(tr))
 250                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 251         else
 252                 trace_function(tr, ip, parent_ip, flags, pc);
 253 }
 254
 255 #else
 256 #define __trace_function trace_function
 257
 258 #ifdef CONFIG_FUNCTION_TRACER
 259 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 260 {
 261         return -1;
 262 }
 263 #endif
 264
 265 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 266 {
 267         return TRACE_TYPE_UNHANDLED;
 268 }
 269
 270 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 271 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 272
 273 #ifdef CONFIG_FUNCTION_TRACER
 274 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 275 static void irqsoff_print_header(struct seq_file *s)
 276 {
 277         trace_default_header(s);
 278 }
 279 #else
 280 static void irqsoff_print_header(struct seq_file *s)
 281 {
 282         trace_latency_header(s);
 283 }
 284 #endif /* CONFIG_FUNCTION_TRACER */
 285 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 286
 287 /*
 288  * Should this new latency be reported/recorded?
 289  */
 290 static bool report_latency(struct trace_array *tr, cycle_t delta)
 291 {
 292         if (tracing_thresh) {
 293                 if (delta < tracing_thresh)
 294                         return false;
 295         } else {
 296                 if (delta <= tr->max_latency)
 297                         return false;
 298         }
 299         return true;
 300 }
 301
 302 static void
 303 check_critical_timing(struct trace_array *tr,
 304                       struct trace_array_cpu *data,
 305                       unsigned long parent_ip,
 306                       int cpu)
 307 {
 308         cycle_t T0, T1, delta;
 309         unsigned long flags;
 310         int pc;
 311
 312         T0 = data->preempt_timestamp;
 313         T1 = ftrace_now(cpu);
 314         delta = T1-T0;
 315
 316         local_save_flags(flags);
 317
 318         pc = preempt_count();
 319
 320         if (!report_latency(tr, delta))
 321                 goto out;
 322
 323         raw_spin_lock_irqsave(&max_trace_lock, flags);
 324
 325         /* check if we are still the max latency */
 326         if (!report_latency(tr, delta))
 327                 goto out_unlock;
 328
 329         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 330         /* Skip 5 functions to get to the irq/preempt enable function */
 331         __trace_stack(tr, flags, 5, pc);
 332
 333         if (data->critical_sequence != max_sequence)
 334                 goto out_unlock;
 335
 336         data->critical_end = parent_ip;
 337
 338         if (likely(!is_tracing_stopped())) {
 339                 tr->max_latency = delta;
 340                 update_max_tr_single(tr, current, cpu);
 341         }
 342
 343         max_sequence++;
 344
 345 out_unlock:
 346         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 347
 348 out:
 349         data->critical_sequence = max_sequence;
 350         data->preempt_timestamp = ftrace_now(cpu);
 351         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 352 }
 353
 354 static inline void
 355 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 356 {
 357         int cpu;
 358         struct trace_array *tr = irqsoff_trace;
 359         struct trace_array_cpu *data;
 360         unsigned long flags;
 361
 362         if (!tracer_enabled || !tracing_is_enabled())
 363                 return;
 364
 365         cpu = raw_smp_processor_id();
 366
 367         if (per_cpu(tracing_cpu, cpu))
 368                 return;
 369
 370         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 371
 372         if (unlikely(!data) || atomic_read(&data->disabled))
 373                 return;
 374
 375         atomic_inc(&data->disabled);
 376
 377         data->critical_sequence = max_sequence;
 378         data->preempt_timestamp = ftrace_now(cpu);
 379         data->critical_start = parent_ip ? : ip;
 380
 381         local_save_flags(flags);
 382
 383         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 384
 385         per_cpu(tracing_cpu, cpu) = 1;
 386
 387         atomic_dec(&data->disabled);
 388 }
 389
 390 static inline void
 391 stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 392 {
 393         int cpu;
 394         struct trace_array *tr = irqsoff_trace;
 395         struct trace_array_cpu *data;
 396         unsigned long flags;
 397
 398         cpu = raw_smp_processor_id();
 399         /* Always clear the tracing cpu on stopping the trace */
 400         if (unlikely(per_cpu(tracing_cpu, cpu)))
 401                 per_cpu(tracing_cpu, cpu) = 0;
 402         else
 403                 return;
 404
 405         if (!tracer_enabled || !tracing_is_enabled())
 406                 return;
 407
 408         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 409
 410         if (unlikely(!data) ||
 411             !data->critical_start || atomic_read(&data->disabled))
 412                 return;
 413
 414         atomic_inc(&data->disabled);
 415
 416         local_save_flags(flags);
 417         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 418         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 419         data->critical_start = 0;
 420         atomic_dec(&data->disabled);
 421 }
 422
 423 /* start and stop critical timings used to for stoppage (in idle) */
 424 void start_critical_timings(void)
 425 {
 426         if (preempt_trace() || irq_trace())
 427                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 428         trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1);
 429 }
 430 EXPORT_SYMBOL_GPL(start_critical_timings);
 431
 432 void stop_critical_timings(void)
 433 {
 434         trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0);
 435         if (preempt_trace() || irq_trace())
 436                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 437 }
 438 EXPORT_SYMBOL_GPL(stop_critical_timings);
 439
 440 #ifdef CONFIG_IRQSOFF_TRACER
 441 #ifdef CONFIG_PROVE_LOCKING
 442 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 443 {
 444         trace_preemptirqsoff_hist_rcuidle(IRQS_ON, 0);
 445         if (!preempt_trace() && irq_trace())
 446                 stop_critical_timing(a0, a1);
 447 }
 448
 449 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 450 {
 451         if (!preempt_trace() && irq_trace())
 452                 start_critical_timing(a0, a1);
 453         trace_preemptirqsoff_hist_rcuidle(IRQS_OFF, 1);
 454 }
 455
 456 #else /* !CONFIG_PROVE_LOCKING */
 457
 458 /*
 459  * Stubs:
 460  */
 461
 462 void trace_softirqs_on(unsigned long ip)
 463 {
 464 }
 465
 466 void trace_softirqs_off(unsigned long ip)
 467 {
 468 }
 469
 470 inline void print_irqtrace_events(struct task_struct *curr)
 471 {
 472 }
 473
 474 /*
 475  * We are only interested in hardirq on/off events:
 476  */
 477 void trace_hardirqs_on(void)
 478 {
 479         trace_preemptirqsoff_hist(IRQS_ON, 0);
 480         if (!preempt_trace() && irq_trace())
 481                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 482 }
 483 EXPORT_SYMBOL(trace_hardirqs_on);
 484
 485 void trace_hardirqs_off(void)
 486 {
 487         if (!preempt_trace() && irq_trace())
 488                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 489         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 490 }
 491 EXPORT_SYMBOL(trace_hardirqs_off);
 492
 493 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 494 {
 495         trace_preemptirqsoff_hist(IRQS_ON, 0);
 496         if (!preempt_trace() && irq_trace())
 497                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 498 }
 499 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 500
 501 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 502 {
 503         if (!preempt_trace() && irq_trace())
 504                 start_critical_timing(CALLER_ADDR0, caller_addr);
 505         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 506 }
 507 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 508
 509 #endif /* CONFIG_PROVE_LOCKING */
 510 #endif /*  CONFIG_IRQSOFF_TRACER */
 511
 512 #ifdef CONFIG_PREEMPT_TRACER
 513 void trace_preempt_on(unsigned long a0, unsigned long a1)
 514 {
 515         trace_preemptirqsoff_hist(PREEMPT_ON, 0);
 516         if (preempt_trace() && !irq_trace())
 517                 stop_critical_timing(a0, a1);
 518 }
 519
 520 void trace_preempt_off(unsigned long a0, unsigned long a1)
 521 {
 522         trace_preemptirqsoff_hist(PREEMPT_ON, 1);
 523         if (preempt_trace() && !irq_trace())
 524                 start_critical_timing(a0, a1);
 525 }
 526 #endif /* CONFIG_PREEMPT_TRACER */
 527
 528 #ifdef CONFIG_FUNCTION_TRACER
 529 static bool function_enabled;
 530
 531 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 532 {
 533         int ret;
 534
 535         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 536         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 537                 return 0;
 538
 539         if (graph)
 540                 ret = register_ftrace_graph(&irqsoff_graph_return,
 541                                             &irqsoff_graph_entry);
 542         else
 543                 ret = register_ftrace_function(tr->ops);
 544
 545         if (!ret)
 546                 function_enabled = true;
 547
 548         return ret;
 549 }
 550
 551 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 552 {
 553         if (!function_enabled)
 554                 return;
 555
 556         if (graph)
 557                 unregister_ftrace_graph();
 558         else
 559                 unregister_ftrace_function(tr->ops);
 560
 561         function_enabled = false;
 562 }
 563
 564 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 565 {
 566         if (!(mask & TRACE_ITER_FUNCTION))
 567                 return 0;
 568
 569         if (set)
 570                 register_irqsoff_function(tr, is_graph(tr), 1);
 571         else
 572                 unregister_irqsoff_function(tr, is_graph(tr));
 573         return 1;
 574 }
 575 #else
 576 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 577 {
 578         return 0;
 579 }
 580 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 581 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 582 {
 583         return 0;
 584 }
 585 #endif /* CONFIG_FUNCTION_TRACER */
 586
 587 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 588 {
 589         struct tracer *tracer = tr->current_trace;
 590
 591         if (irqsoff_function_set(tr, mask, set))
 592                 return 0;
 593
 594 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 595         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 596                 return irqsoff_display_graph(tr, set);
 597 #endif
 598
 599         return trace_keep_overwrite(tracer, mask, set);
 600 }
 601
 602 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 603 {
 604         int ret;
 605
 606         ret = register_irqsoff_function(tr, graph, 0);
 607
 608         if (!ret && tracing_is_enabled())
 609                 tracer_enabled = 1;
 610         else
 611                 tracer_enabled = 0;
 612
 613         return ret;
 614 }
 615
 616 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 617 {
 618         tracer_enabled = 0;
 619
 620         unregister_irqsoff_function(tr, graph);
 621 }
 622
 623 static bool irqsoff_busy;
 624
 625 static int __irqsoff_tracer_init(struct trace_array *tr)
 626 {
 627         if (irqsoff_busy)
 628                 return -EBUSY;
 629
 630         save_flags = tr->trace_flags;
 631
 632         /* non overwrite screws up the latency tracers */
 633         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 634         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 635
 636         tr->max_latency = 0;
 637         irqsoff_trace = tr;
 638         /* make sure that the tracer is visible */
 639         smp_wmb();
 640         tracing_reset_online_cpus(&tr->trace_buffer);
 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);