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/debugfs.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/module.h>
  16 #include <linux/ftrace.h>
  17 #include <linux/fs.h>
  18
  19 #include "trace.h"
  20
  21 static struct trace_array               *irqsoff_trace __read_mostly;
  22 static int                              tracer_enabled __read_mostly;
  23
  24 static DEFINE_PER_CPU(int, tracing_cpu);
  25
  26 static DEFINE_RAW_SPINLOCK(max_trace_lock);
  27
  28 enum {
  29         TRACER_IRQS_OFF         = (1 << 1),
  30         TRACER_PREEMPT_OFF      = (1 << 2),
  31 };
  32
  33 static int trace_type __read_mostly;
  34
  35 static int save_flags;
  36 static bool function_enabled;
  37
  38 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
  39 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
  40
  41 #ifdef CONFIG_PREEMPT_TRACER
  42 static inline int
  43 preempt_trace(void)
  44 {
  45         return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
  46 }
  47 #else
  48 # define preempt_trace() (0)
  49 #endif
  50
  51 #ifdef CONFIG_IRQSOFF_TRACER
  52 static inline int
  53 irq_trace(void)
  54 {
  55         return ((trace_type & TRACER_IRQS_OFF) &&
  56                 irqs_disabled());
  57 }
  58 #else
  59 # define irq_trace() (0)
  60 #endif
  61
  62 #define TRACE_DISPLAY_GRAPH     1
  63
  64 static struct tracer_opt trace_opts[] = {
  65 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  66         /* display latency trace as call graph */
  67         { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
  68 #endif
  69         { } /* Empty entry */
  70 };
  71
  72 static struct tracer_flags tracer_flags = {
  73         .val  = 0,
  74         .opts = trace_opts,
  75 };
  76
  77 #define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
  78
  79 /*
  80  * Sequence count - we record it when starting a measurement and
  81  * skip the latency if the sequence has changed - some other section
  82  * did a maximum and could disturb our measurement with serial console
  83  * printouts, etc. Truly coinciding maximum latencies should be rare
  84  * and what happens together happens separately as well, so this doesn't
  85  * decrease the validity of the maximum found:
  86  */
  87 static __cacheline_aligned_in_smp       unsigned long max_sequence;
  88
  89 #ifdef CONFIG_FUNCTION_TRACER
  90 /*
  91  * Prologue for the preempt and irqs off function tracers.
  92  *
  93  * Returns 1 if it is OK to continue, and data->disabled is
  94  *            incremented.
  95  *         0 if the trace is to be ignored, and data->disabled
  96  *            is kept the same.
  97  *
  98  * Note, this function is also used outside this ifdef but
  99  *  inside the #ifdef of the function graph tracer below.
 100  *  This is OK, since the function graph tracer is
 101  *  dependent on the function tracer.
 102  */
 103 static int func_prolog_dec(struct trace_array *tr,
 104                            struct trace_array_cpu **data,
 105                            unsigned long *flags)
 106 {
 107         long disabled;
 108         int cpu;
 109
 110         /*
 111          * Does not matter if we preempt. We test the flags
 112          * afterward, to see if irqs are disabled or not.
 113          * If we preempt and get a false positive, the flags
 114          * test will fail.
 115          */
 116         cpu = raw_smp_processor_id();
 117         if (likely(!per_cpu(tracing_cpu, cpu)))
 118                 return 0;
 119
 120         local_save_flags(*flags);
 121         /* slight chance to get a false positive on tracing_cpu */
 122         if (!irqs_disabled_flags(*flags))
 123                 return 0;
 124
 125         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 126         disabled = atomic_inc_return(&(*data)->disabled);
 127
 128         if (likely(disabled == 1))
 129                 return 1;
 130
 131         atomic_dec(&(*data)->disabled);
 132
 133         return 0;
 134 }
 135
 136 /*
 137  * irqsoff uses its own tracer function to keep the overhead down:
 138  */
 139 static void
 140 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
 141                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 142 {
 143         struct trace_array *tr = irqsoff_trace;
 144         struct trace_array_cpu *data;
 145         unsigned long flags;
 146
 147         if (!func_prolog_dec(tr, &data, &flags))
 148                 return;
 149
 150         trace_function(tr, ip, parent_ip, flags, preempt_count());
 151
 152         atomic_dec(&data->disabled);
 153 }
 154 #endif /* CONFIG_FUNCTION_TRACER */
 155
 156 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 157 static int
 158 irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 159 {
 160         int cpu;
 161
 162         if (!(bit & TRACE_DISPLAY_GRAPH))
 163                 return -EINVAL;
 164
 165         if (!(is_graph() ^ set))
 166                 return 0;
 167
 168         stop_irqsoff_tracer(irqsoff_trace, !set);
 169
 170         for_each_possible_cpu(cpu)
 171                 per_cpu(tracing_cpu, cpu) = 0;
 172
 173         tr->max_latency = 0;
 174         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 175
 176         return start_irqsoff_tracer(irqsoff_trace, set);
 177 }
 178
 179 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 180 {
 181         struct trace_array *tr = irqsoff_trace;
 182         struct trace_array_cpu *data;
 183         unsigned long flags;
 184         int ret;
 185         int pc;
 186
 187         if (!func_prolog_dec(tr, &data, &flags))
 188                 return 0;
 189
 190         pc = preempt_count();
 191         ret = __trace_graph_entry(tr, trace, flags, pc);
 192         atomic_dec(&data->disabled);
 193
 194         return ret;
 195 }
 196
 197 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 198 {
 199         struct trace_array *tr = irqsoff_trace;
 200         struct trace_array_cpu *data;
 201         unsigned long flags;
 202         int pc;
 203
 204         if (!func_prolog_dec(tr, &data, &flags))
 205                 return;
 206
 207         pc = preempt_count();
 208         __trace_graph_return(tr, trace, flags, pc);
 209         atomic_dec(&data->disabled);
 210 }
 211
 212 static void irqsoff_trace_open(struct trace_iterator *iter)
 213 {
 214         if (is_graph())
 215                 graph_trace_open(iter);
 216
 217 }
 218
 219 static void irqsoff_trace_close(struct trace_iterator *iter)
 220 {
 221         if (iter->private)
 222                 graph_trace_close(iter);
 223 }
 224
 225 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 226                             TRACE_GRAPH_PRINT_PROC | \
 227                             TRACE_GRAPH_PRINT_ABS_TIME | \
 228                             TRACE_GRAPH_PRINT_DURATION)
 229
 230 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 231 {
 232         /*
 233          * In graph mode call the graph tracer output function,
 234          * otherwise go with the TRACE_FN event handler
 235          */
 236         if (is_graph())
 237                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 238
 239         return TRACE_TYPE_UNHANDLED;
 240 }
 241
 242 static void irqsoff_print_header(struct seq_file *s)
 243 {
 244         if (is_graph())
 245                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 246         else
 247                 trace_default_header(s);
 248 }
 249
 250 static void
 251 __trace_function(struct trace_array *tr,
 252                  unsigned long ip, unsigned long parent_ip,
 253                  unsigned long flags, int pc)
 254 {
 255         if (is_graph())
 256                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 257         else
 258                 trace_function(tr, ip, parent_ip, flags, pc);
 259 }
 260
 261 #else
 262 #define __trace_function trace_function
 263
 264 static int
 265 irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 266 {
 267         return -EINVAL;
 268 }
 269
 270 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 271 {
 272         return -1;
 273 }
 274
 275 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 276 {
 277         return TRACE_TYPE_UNHANDLED;
 278 }
 279
 280 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 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_print_header(struct seq_file *s)
 286 {
 287         trace_default_header(s);
 288 }
 289 #else
 290 static void irqsoff_print_header(struct seq_file *s)
 291 {
 292         trace_latency_header(s);
 293 }
 294 #endif /* CONFIG_FUNCTION_TRACER */
 295 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 296
 297 /*
 298  * Should this new latency be reported/recorded?
 299  */
 300 static int report_latency(struct trace_array *tr, cycle_t delta)
 301 {
 302         if (tracing_thresh) {
 303                 if (delta < tracing_thresh)
 304                         return 0;
 305         } else {
 306                 if (delta <= tr->max_latency)
 307                         return 0;
 308         }
 309         return 1;
 310 }
 311
 312 static void
 313 check_critical_timing(struct trace_array *tr,
 314                       struct trace_array_cpu *data,
 315                       unsigned long parent_ip,
 316                       int cpu)
 317 {
 318         cycle_t T0, T1, delta;
 319         unsigned long flags;
 320         int pc;
 321
 322         T0 = data->preempt_timestamp;
 323         T1 = ftrace_now(cpu);
 324         delta = T1-T0;
 325
 326         local_save_flags(flags);
 327
 328         pc = preempt_count();
 329
 330         if (!report_latency(tr, delta))
 331                 goto out;
 332
 333         raw_spin_lock_irqsave(&max_trace_lock, flags);
 334
 335         /* check if we are still the max latency */
 336         if (!report_latency(tr, delta))
 337                 goto out_unlock;
 338
 339         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 340         /* Skip 5 functions to get to the irq/preempt enable function */
 341         __trace_stack(tr, flags, 5, pc);
 342
 343         if (data->critical_sequence != max_sequence)
 344                 goto out_unlock;
 345
 346         data->critical_end = parent_ip;
 347
 348         if (likely(!is_tracing_stopped())) {
 349                 tr->max_latency = delta;
 350                 update_max_tr_single(tr, current, cpu);
 351         }
 352
 353         max_sequence++;
 354
 355 out_unlock:
 356         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 357
 358 out:
 359         data->critical_sequence = max_sequence;
 360         data->preempt_timestamp = ftrace_now(cpu);
 361         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 362 }
 363
 364 static inline void
 365 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 366 {
 367         int cpu;
 368         struct trace_array *tr = irqsoff_trace;
 369         struct trace_array_cpu *data;
 370         unsigned long flags;
 371
 372         if (!tracer_enabled || !tracing_is_enabled())
 373                 return;
 374
 375         cpu = raw_smp_processor_id();
 376
 377         if (per_cpu(tracing_cpu, cpu))
 378                 return;
 379
 380         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 381
 382         if (unlikely(!data) || atomic_read(&data->disabled))
 383                 return;
 384
 385         atomic_inc(&data->disabled);
 386
 387         data->critical_sequence = max_sequence;
 388         data->preempt_timestamp = ftrace_now(cpu);
 389         data->critical_start = parent_ip ? : ip;
 390
 391         local_save_flags(flags);
 392
 393         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 394
 395         per_cpu(tracing_cpu, cpu) = 1;
 396
 397         atomic_dec(&data->disabled);
 398 }
 399
 400 static inline void
 401 stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 402 {
 403         int cpu;
 404         struct trace_array *tr = irqsoff_trace;
 405         struct trace_array_cpu *data;
 406         unsigned long flags;
 407
 408         cpu = raw_smp_processor_id();
 409         /* Always clear the tracing cpu on stopping the trace */
 410         if (unlikely(per_cpu(tracing_cpu, cpu)))
 411                 per_cpu(tracing_cpu, cpu) = 0;
 412         else
 413                 return;
 414
 415         if (!tracer_enabled || !tracing_is_enabled())
 416                 return;
 417
 418         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 419
 420         if (unlikely(!data) ||
 421             !data->critical_start || atomic_read(&data->disabled))
 422                 return;
 423
 424         atomic_inc(&data->disabled);
 425
 426         local_save_flags(flags);
 427         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 428         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 429         data->critical_start = 0;
 430         atomic_dec(&data->disabled);
 431 }
 432
 433 /* start and stop critical timings used to for stoppage (in idle) */
 434 void start_critical_timings(void)
 435 {
 436         if (preempt_trace() || irq_trace())
 437                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 438 }
 439 EXPORT_SYMBOL_GPL(start_critical_timings);
 440
 441 void stop_critical_timings(void)
 442 {
 443         if (preempt_trace() || irq_trace())
 444                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 445 }
 446 EXPORT_SYMBOL_GPL(stop_critical_timings);
 447
 448 #ifdef CONFIG_IRQSOFF_TRACER
 449 #ifdef CONFIG_PROVE_LOCKING
 450 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 451 {
 452         if (!preempt_trace() && irq_trace())
 453                 stop_critical_timing(a0, a1);
 454 }
 455
 456 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 457 {
 458         if (!preempt_trace() && irq_trace())
 459                 start_critical_timing(a0, a1);
 460 }
 461
 462 #else /* !CONFIG_PROVE_LOCKING */
 463
 464 /*
 465  * Stubs:
 466  */
 467
 468 void trace_softirqs_on(unsigned long ip)
 469 {
 470 }
 471
 472 void trace_softirqs_off(unsigned long ip)
 473 {
 474 }
 475
 476 inline void print_irqtrace_events(struct task_struct *curr)
 477 {
 478 }
 479
 480 /*
 481  * We are only interested in hardirq on/off events:
 482  */
 483 void trace_hardirqs_on(void)
 484 {
 485         if (!preempt_trace() && irq_trace())
 486                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 487 }
 488 EXPORT_SYMBOL(trace_hardirqs_on);
 489
 490 void trace_hardirqs_off(void)
 491 {
 492         if (!preempt_trace() && irq_trace())
 493                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 494 }
 495 EXPORT_SYMBOL(trace_hardirqs_off);
 496
 497 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 498 {
 499         if (!preempt_trace() && irq_trace())
 500                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 501 }
 502 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 503
 504 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 505 {
 506         if (!preempt_trace() && irq_trace())
 507                 start_critical_timing(CALLER_ADDR0, caller_addr);
 508 }
 509 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 510
 511 #endif /* CONFIG_PROVE_LOCKING */
 512 #endif /*  CONFIG_IRQSOFF_TRACER */
 513
 514 #ifdef CONFIG_PREEMPT_TRACER
 515 void trace_preempt_on(unsigned long a0, unsigned long a1)
 516 {
 517         if (preempt_trace() && !irq_trace())
 518                 stop_critical_timing(a0, a1);
 519 }
 520
 521 void trace_preempt_off(unsigned long a0, unsigned long a1)
 522 {
 523         if (preempt_trace() && !irq_trace())
 524                 start_critical_timing(a0, a1);
 525 }
 526 #endif /* CONFIG_PREEMPT_TRACER */
 527
 528 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 529 {
 530         int ret;
 531
 532         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 533         if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
 534                 return 0;
 535
 536         if (graph)
 537                 ret = register_ftrace_graph(&irqsoff_graph_return,
 538                                             &irqsoff_graph_entry);
 539         else
 540                 ret = register_ftrace_function(tr->ops);
 541
 542         if (!ret)
 543                 function_enabled = true;
 544
 545         return ret;
 546 }
 547
 548 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 549 {
 550         if (!function_enabled)
 551                 return;
 552
 553         if (graph)
 554                 unregister_ftrace_graph();
 555         else
 556                 unregister_ftrace_function(tr->ops);
 557
 558         function_enabled = false;
 559 }
 560
 561 static void irqsoff_function_set(struct trace_array *tr, int set)
 562 {
 563         if (set)
 564                 register_irqsoff_function(tr, is_graph(), 1);
 565         else
 566                 unregister_irqsoff_function(tr, is_graph());
 567 }
 568
 569 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 570 {
 571         struct tracer *tracer = tr->current_trace;
 572
 573         if (mask & TRACE_ITER_FUNCTION)
 574                 irqsoff_function_set(tr, set);
 575
 576         return trace_keep_overwrite(tracer, mask, set);
 577 }
 578
 579 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 580 {
 581         int ret;
 582
 583         ret = register_irqsoff_function(tr, graph, 0);
 584
 585         if (!ret && tracing_is_enabled())
 586                 tracer_enabled = 1;
 587         else
 588                 tracer_enabled = 0;
 589
 590         return ret;
 591 }
 592
 593 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 594 {
 595         tracer_enabled = 0;
 596
 597         unregister_irqsoff_function(tr, graph);
 598 }
 599
 600 static bool irqsoff_busy;
 601
 602 static int __irqsoff_tracer_init(struct trace_array *tr)
 603 {
 604         if (irqsoff_busy)
 605                 return -EBUSY;
 606
 607         save_flags = trace_flags;
 608
 609         /* non overwrite screws up the latency tracers */
 610         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 611         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 612
 613         tr->max_latency = 0;
 614         irqsoff_trace = tr;
 615         /* make sure that the tracer is visible */
 616         smp_wmb();
 617         tracing_reset_online_cpus(&tr->trace_buffer);
 618
 619         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 620
 621         /* Only toplevel instance supports graph tracing */
 622         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 623                                       is_graph())))
 624                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 625
 626         irqsoff_busy = true;
 627         return 0;
 628 }
 629
 630 static void irqsoff_tracer_reset(struct trace_array *tr)
 631 {
 632         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 633         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 634
 635         stop_irqsoff_tracer(tr, is_graph());
 636
 637         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 638         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 639         ftrace_reset_array_ops(tr);
 640
 641         irqsoff_busy = false;
 642 }
 643
 644 static void irqsoff_tracer_start(struct trace_array *tr)
 645 {
 646         tracer_enabled = 1;
 647 }
 648
 649 static void irqsoff_tracer_stop(struct trace_array *tr)
 650 {
 651         tracer_enabled = 0;
 652 }
 653
 654 #ifdef CONFIG_IRQSOFF_TRACER
 655 static int irqsoff_tracer_init(struct trace_array *tr)
 656 {
 657         trace_type = TRACER_IRQS_OFF;
 658
 659         return __irqsoff_tracer_init(tr);
 660 }
 661 static struct tracer irqsoff_tracer __read_mostly =
 662 {
 663         .name           = "irqsoff",
 664         .init           = irqsoff_tracer_init,
 665         .reset          = irqsoff_tracer_reset,
 666         .start          = irqsoff_tracer_start,
 667         .stop           = irqsoff_tracer_stop,
 668         .print_max      = true,
 669         .print_header   = irqsoff_print_header,
 670         .print_line     = irqsoff_print_line,
 671         .flags          = &tracer_flags,
 672         .set_flag       = irqsoff_set_flag,
 673         .flag_changed   = irqsoff_flag_changed,
 674 #ifdef CONFIG_FTRACE_SELFTEST
 675         .selftest    = trace_selftest_startup_irqsoff,
 676 #endif
 677         .open           = irqsoff_trace_open,
 678         .close          = irqsoff_trace_close,
 679         .allow_instances = true,
 680         .use_max_tr     = true,
 681 };
 682 # define register_irqsoff(trace) register_tracer(&trace)
 683 #else
 684 # define register_irqsoff(trace) do { } while (0)
 685 #endif
 686
 687 #ifdef CONFIG_PREEMPT_TRACER
 688 static int preemptoff_tracer_init(struct trace_array *tr)
 689 {
 690         trace_type = TRACER_PREEMPT_OFF;
 691
 692         return __irqsoff_tracer_init(tr);
 693 }
 694
 695 static struct tracer preemptoff_tracer __read_mostly =
 696 {
 697         .name           = "preemptoff",
 698         .init           = preemptoff_tracer_init,
 699         .reset          = irqsoff_tracer_reset,
 700         .start          = irqsoff_tracer_start,
 701         .stop           = irqsoff_tracer_stop,
 702         .print_max      = true,
 703         .print_header   = irqsoff_print_header,
 704         .print_line     = irqsoff_print_line,
 705         .flags          = &tracer_flags,
 706         .set_flag       = irqsoff_set_flag,
 707         .flag_changed   = irqsoff_flag_changed,
 708 #ifdef CONFIG_FTRACE_SELFTEST
 709         .selftest    = trace_selftest_startup_preemptoff,
 710 #endif
 711         .open           = irqsoff_trace_open,
 712         .close          = irqsoff_trace_close,
 713         .allow_instances = true,
 714         .use_max_tr     = true,
 715 };
 716 # define register_preemptoff(trace) register_tracer(&trace)
 717 #else
 718 # define register_preemptoff(trace) do { } while (0)
 719 #endif
 720
 721 #if defined(CONFIG_IRQSOFF_TRACER) && \
 722         defined(CONFIG_PREEMPT_TRACER)
 723
 724 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 725 {
 726         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 727
 728         return __irqsoff_tracer_init(tr);
 729 }
 730
 731 static struct tracer preemptirqsoff_tracer __read_mostly =
 732 {
 733         .name           = "preemptirqsoff",
 734         .init           = preemptirqsoff_tracer_init,
 735         .reset          = irqsoff_tracer_reset,
 736         .start          = irqsoff_tracer_start,
 737         .stop           = irqsoff_tracer_stop,
 738         .print_max      = true,
 739         .print_header   = irqsoff_print_header,
 740         .print_line     = irqsoff_print_line,
 741         .flags          = &tracer_flags,
 742         .set_flag       = irqsoff_set_flag,
 743         .flag_changed   = irqsoff_flag_changed,
 744 #ifdef CONFIG_FTRACE_SELFTEST
 745         .selftest    = trace_selftest_startup_preemptirqsoff,
 746 #endif
 747         .open           = irqsoff_trace_open,
 748         .close          = irqsoff_trace_close,
 749         .allow_instances = true,
 750         .use_max_tr     = true,
 751 };
 752
 753 # define register_preemptirqsoff(trace) register_tracer(&trace)
 754 #else
 755 # define register_preemptirqsoff(trace) do { } while (0)
 756 #endif
 757
 758 __init static int init_irqsoff_tracer(void)
 759 {
 760         register_irqsoff(irqsoff_tracer);
 761         register_preemptoff(preemptoff_tracer);
 762         register_preemptirqsoff(preemptirqsoff_tracer);
 763
 764         return 0;
 765 }
 766 core_initcall(init_irqsoff_tracer);