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 static bool function_enabled;
  36
  37 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
  38 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
  39
  40 #ifdef CONFIG_PREEMPT_TRACER
  41 static inline int
  42 preempt_trace(void)
  43 {
  44         return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
  45 }
  46 #else
  47 # define preempt_trace() (0)
  48 #endif
  49
  50 #ifdef CONFIG_IRQSOFF_TRACER
  51 static inline int
  52 irq_trace(void)
  53 {
  54         return ((trace_type & TRACER_IRQS_OFF) &&
  55                 irqs_disabled());
  56 }
  57 #else
  58 # define irq_trace() (0)
  59 #endif
  60
  61 #define TRACE_DISPLAY_GRAPH     1
  62
  63 static struct tracer_opt trace_opts[] = {
  64 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  65         /* display latency trace as call graph */
  66         { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
  67 #endif
  68         { } /* Empty entry */
  69 };
  70
  71 static struct tracer_flags tracer_flags = {
  72         .val  = 0,
  73         .opts = trace_opts,
  74 };
  75
  76 #define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
  77
  78 /*
  79  * Sequence count - we record it when starting a measurement and
  80  * skip the latency if the sequence has changed - some other section
  81  * did a maximum and could disturb our measurement with serial console
  82  * printouts, etc. Truly coinciding maximum latencies should be rare
  83  * and what happens together happens separately as well, so this doesn't
  84  * decrease the validity of the maximum found:
  85  */
  86 static __cacheline_aligned_in_smp       unsigned long max_sequence;
  87
  88 #ifdef CONFIG_FUNCTION_TRACER
  89 /*
  90  * Prologue for the preempt and irqs off function tracers.
  91  *
  92  * Returns 1 if it is OK to continue, and data->disabled is
  93  *            incremented.
  94  *         0 if the trace is to be ignored, and data->disabled
  95  *            is kept the same.
  96  *
  97  * Note, this function is also used outside this ifdef but
  98  *  inside the #ifdef of the function graph tracer below.
  99  *  This is OK, since the function graph tracer is
 100  *  dependent on the function tracer.
 101  */
 102 static int func_prolog_dec(struct trace_array *tr,
 103                            struct trace_array_cpu **data,
 104                            unsigned long *flags)
 105 {
 106         long disabled;
 107         int cpu;
 108
 109         /*
 110          * Does not matter if we preempt. We test the flags
 111          * afterward, to see if irqs are disabled or not.
 112          * If we preempt and get a false positive, the flags
 113          * test will fail.
 114          */
 115         cpu = raw_smp_processor_id();
 116         if (likely(!per_cpu(tracing_cpu, cpu)))
 117                 return 0;
 118
 119         local_save_flags(*flags);
 120         /* slight chance to get a false positive on tracing_cpu */
 121         if (!irqs_disabled_flags(*flags))
 122                 return 0;
 123
 124         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 125         disabled = atomic_inc_return(&(*data)->disabled);
 126
 127         if (likely(disabled == 1))
 128                 return 1;
 129
 130         atomic_dec(&(*data)->disabled);
 131
 132         return 0;
 133 }
 134
 135 /*
 136  * irqsoff uses its own tracer function to keep the overhead down:
 137  */
 138 static void
 139 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
 140                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 141 {
 142         struct trace_array *tr = irqsoff_trace;
 143         struct trace_array_cpu *data;
 144         unsigned long flags;
 145
 146         if (!func_prolog_dec(tr, &data, &flags))
 147                 return;
 148
 149         trace_function(tr, ip, parent_ip, flags, preempt_count());
 150
 151         atomic_dec(&data->disabled);
 152 }
 153 #endif /* CONFIG_FUNCTION_TRACER */
 154
 155 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 156 static int
 157 irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 158 {
 159         int cpu;
 160
 161         if (!(bit & TRACE_DISPLAY_GRAPH))
 162                 return -EINVAL;
 163
 164         if (!(is_graph() ^ set))
 165                 return 0;
 166
 167         stop_irqsoff_tracer(irqsoff_trace, !set);
 168
 169         for_each_possible_cpu(cpu)
 170                 per_cpu(tracing_cpu, cpu) = 0;
 171
 172         tr->max_latency = 0;
 173         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 174
 175         return start_irqsoff_tracer(irqsoff_trace, set);
 176 }
 177
 178 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 179 {
 180         struct trace_array *tr = irqsoff_trace;
 181         struct trace_array_cpu *data;
 182         unsigned long flags;
 183         int ret;
 184         int pc;
 185
 186         if (!func_prolog_dec(tr, &data, &flags))
 187                 return 0;
 188
 189         pc = preempt_count();
 190         ret = __trace_graph_entry(tr, trace, flags, pc);
 191         atomic_dec(&data->disabled);
 192
 193         return ret;
 194 }
 195
 196 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 197 {
 198         struct trace_array *tr = irqsoff_trace;
 199         struct trace_array_cpu *data;
 200         unsigned long flags;
 201         int pc;
 202
 203         if (!func_prolog_dec(tr, &data, &flags))
 204                 return;
 205
 206         pc = preempt_count();
 207         __trace_graph_return(tr, trace, flags, pc);
 208         atomic_dec(&data->disabled);
 209 }
 210
 211 static void irqsoff_trace_open(struct trace_iterator *iter)
 212 {
 213         if (is_graph())
 214                 graph_trace_open(iter);
 215
 216 }
 217
 218 static void irqsoff_trace_close(struct trace_iterator *iter)
 219 {
 220         if (iter->private)
 221                 graph_trace_close(iter);
 222 }
 223
 224 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 225                             TRACE_GRAPH_PRINT_PROC | \
 226                             TRACE_GRAPH_PRINT_ABS_TIME | \
 227                             TRACE_GRAPH_PRINT_DURATION)
 228
 229 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 230 {
 231         /*
 232          * In graph mode call the graph tracer output function,
 233          * otherwise go with the TRACE_FN event handler
 234          */
 235         if (is_graph())
 236                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 237
 238         return TRACE_TYPE_UNHANDLED;
 239 }
 240
 241 static void irqsoff_print_header(struct seq_file *s)
 242 {
 243         if (is_graph())
 244                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 245         else
 246                 trace_default_header(s);
 247 }
 248
 249 static void
 250 __trace_function(struct trace_array *tr,
 251                  unsigned long ip, unsigned long parent_ip,
 252                  unsigned long flags, int pc)
 253 {
 254         if (is_graph())
 255                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 256         else
 257                 trace_function(tr, ip, parent_ip, flags, pc);
 258 }
 259
 260 #else
 261 #define __trace_function trace_function
 262
 263 static int
 264 irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 265 {
 266         return -EINVAL;
 267 }
 268
 269 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 270 {
 271         return -1;
 272 }
 273
 274 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 275 {
 276         return TRACE_TYPE_UNHANDLED;
 277 }
 278
 279 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 280 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 281 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 282
 283 #ifdef CONFIG_FUNCTION_TRACER
 284 static void irqsoff_print_header(struct seq_file *s)
 285 {
 286         trace_default_header(s);
 287 }
 288 #else
 289 static void irqsoff_print_header(struct seq_file *s)
 290 {
 291         trace_latency_header(s);
 292 }
 293 #endif /* CONFIG_FUNCTION_TRACER */
 294 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 295
 296 /*
 297  * Should this new latency be reported/recorded?
 298  */
 299 static int report_latency(struct trace_array *tr, cycle_t delta)
 300 {
 301         if (tracing_thresh) {
 302                 if (delta < tracing_thresh)
 303                         return 0;
 304         } else {
 305                 if (delta <= tr->max_latency)
 306                         return 0;
 307         }
 308         return 1;
 309 }
 310
 311 static void
 312 check_critical_timing(struct trace_array *tr,
 313                       struct trace_array_cpu *data,
 314                       unsigned long parent_ip,
 315                       int cpu)
 316 {
 317         cycle_t T0, T1, delta;
 318         unsigned long flags;
 319         int pc;
 320
 321         T0 = data->preempt_timestamp;
 322         T1 = ftrace_now(cpu);
 323         delta = T1-T0;
 324
 325         local_save_flags(flags);
 326
 327         pc = preempt_count();
 328
 329         if (!report_latency(tr, delta))
 330                 goto out;
 331
 332         raw_spin_lock_irqsave(&max_trace_lock, flags);
 333
 334         /* check if we are still the max latency */
 335         if (!report_latency(tr, delta))
 336                 goto out_unlock;
 337
 338         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 339         /* Skip 5 functions to get to the irq/preempt enable function */
 340         __trace_stack(tr, flags, 5, pc);
 341
 342         if (data->critical_sequence != max_sequence)
 343                 goto out_unlock;
 344
 345         data->critical_end = parent_ip;
 346
 347         if (likely(!is_tracing_stopped())) {
 348                 tr->max_latency = delta;
 349                 update_max_tr_single(tr, current, cpu);
 350         }
 351
 352         max_sequence++;
 353
 354 out_unlock:
 355         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 356
 357 out:
 358         data->critical_sequence = max_sequence;
 359         data->preempt_timestamp = ftrace_now(cpu);
 360         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 361 }
 362
 363 static inline void
 364 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 365 {
 366         int cpu;
 367         struct trace_array *tr = irqsoff_trace;
 368         struct trace_array_cpu *data;
 369         unsigned long flags;
 370
 371         if (!tracer_enabled || !tracing_is_enabled())
 372                 return;
 373
 374         cpu = raw_smp_processor_id();
 375
 376         if (per_cpu(tracing_cpu, cpu))
 377                 return;
 378
 379         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 380
 381         if (unlikely(!data) || atomic_read(&data->disabled))
 382                 return;
 383
 384         atomic_inc(&data->disabled);
 385
 386         data->critical_sequence = max_sequence;
 387         data->preempt_timestamp = ftrace_now(cpu);
 388         data->critical_start = parent_ip ? : ip;
 389
 390         local_save_flags(flags);
 391
 392         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 393
 394         per_cpu(tracing_cpu, cpu) = 1;
 395
 396         atomic_dec(&data->disabled);
 397 }
 398
 399 static inline void
 400 stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 401 {
 402         int cpu;
 403         struct trace_array *tr = irqsoff_trace;
 404         struct trace_array_cpu *data;
 405         unsigned long flags;
 406
 407         cpu = raw_smp_processor_id();
 408         /* Always clear the tracing cpu on stopping the trace */
 409         if (unlikely(per_cpu(tracing_cpu, cpu)))
 410                 per_cpu(tracing_cpu, cpu) = 0;
 411         else
 412                 return;
 413
 414         if (!tracer_enabled || !tracing_is_enabled())
 415                 return;
 416
 417         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 418
 419         if (unlikely(!data) ||
 420             !data->critical_start || atomic_read(&data->disabled))
 421                 return;
 422
 423         atomic_inc(&data->disabled);
 424
 425         local_save_flags(flags);
 426         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 427         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 428         data->critical_start = 0;
 429         atomic_dec(&data->disabled);
 430 }
 431
 432 /* start and stop critical timings used to for stoppage (in idle) */
 433 void start_critical_timings(void)
 434 {
 435         if (preempt_trace() || irq_trace())
 436                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 437         trace_preemptirqsoff_hist(TRACE_START, 1);
 438 }
 439 EXPORT_SYMBOL_GPL(start_critical_timings);
 440
 441 void stop_critical_timings(void)
 442 {
 443         trace_preemptirqsoff_hist(TRACE_STOP, 0);
 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         trace_preemptirqsoff_hist(IRQS_ON, 0);
 454         if (!preempt_trace() && irq_trace())
 455                 stop_critical_timing(a0, a1);
 456 }
 457
 458 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 459 {
 460         if (!preempt_trace() && irq_trace())
 461                 start_critical_timing(a0, a1);
 462         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 463 }
 464
 465 #else /* !CONFIG_PROVE_LOCKING */
 466
 467 /*
 468  * Stubs:
 469  */
 470
 471 void trace_softirqs_on(unsigned long ip)
 472 {
 473 }
 474
 475 void trace_softirqs_off(unsigned long ip)
 476 {
 477 }
 478
 479 inline void print_irqtrace_events(struct task_struct *curr)
 480 {
 481 }
 482
 483 /*
 484  * We are only interested in hardirq on/off events:
 485  */
 486 void trace_hardirqs_on(void)
 487 {
 488         trace_preemptirqsoff_hist(IRQS_ON, 0);
 489         if (!preempt_trace() && irq_trace())
 490                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 491 }
 492 EXPORT_SYMBOL(trace_hardirqs_on);
 493
 494 void trace_hardirqs_off(void)
 495 {
 496         if (!preempt_trace() && irq_trace())
 497                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 498         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 499 }
 500 EXPORT_SYMBOL(trace_hardirqs_off);
 501
 502 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 503 {
 504         trace_preemptirqsoff_hist(IRQS_ON, 0);
 505         if (!preempt_trace() && irq_trace())
 506                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 507 }
 508 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 509
 510 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 511 {
 512         if (!preempt_trace() && irq_trace())
 513                 start_critical_timing(CALLER_ADDR0, caller_addr);
 514         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 515 }
 516 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 517
 518 #endif /* CONFIG_PROVE_LOCKING */
 519 #endif /*  CONFIG_IRQSOFF_TRACER */
 520
 521 #ifdef CONFIG_PREEMPT_TRACER
 522 void trace_preempt_on(unsigned long a0, unsigned long a1)
 523 {
 524         trace_preemptirqsoff_hist(PREEMPT_ON, 0);
 525         if (preempt_trace() && !irq_trace())
 526                 stop_critical_timing(a0, a1);
 527 }
 528
 529 void trace_preempt_off(unsigned long a0, unsigned long a1)
 530 {
 531         trace_preemptirqsoff_hist(PREEMPT_ON, 1);
 532         if (preempt_trace() && !irq_trace())
 533                 start_critical_timing(a0, a1);
 534 }
 535 #endif /* CONFIG_PREEMPT_TRACER */
 536
 537 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 538 {
 539         int ret;
 540
 541         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 542         if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
 543                 return 0;
 544
 545         if (graph)
 546                 ret = register_ftrace_graph(&irqsoff_graph_return,
 547                                             &irqsoff_graph_entry);
 548         else
 549                 ret = register_ftrace_function(tr->ops);
 550
 551         if (!ret)
 552                 function_enabled = true;
 553
 554         return ret;
 555 }
 556
 557 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 558 {
 559         if (!function_enabled)
 560                 return;
 561
 562         if (graph)
 563                 unregister_ftrace_graph();
 564         else
 565                 unregister_ftrace_function(tr->ops);
 566
 567         function_enabled = false;
 568 }
 569
 570 static void irqsoff_function_set(struct trace_array *tr, int set)
 571 {
 572         if (set)
 573                 register_irqsoff_function(tr, is_graph(), 1);
 574         else
 575                 unregister_irqsoff_function(tr, is_graph());
 576 }
 577
 578 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 579 {
 580         struct tracer *tracer = tr->current_trace;
 581
 582         if (mask & TRACE_ITER_FUNCTION)
 583                 irqsoff_function_set(tr, set);
 584
 585         return trace_keep_overwrite(tracer, mask, set);
 586 }
 587
 588 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 589 {
 590         int ret;
 591
 592         ret = register_irqsoff_function(tr, graph, 0);
 593
 594         if (!ret && tracing_is_enabled())
 595                 tracer_enabled = 1;
 596         else
 597                 tracer_enabled = 0;
 598
 599         return ret;
 600 }
 601
 602 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 603 {
 604         tracer_enabled = 0;
 605
 606         unregister_irqsoff_function(tr, graph);
 607 }
 608
 609 static bool irqsoff_busy;
 610
 611 static int __irqsoff_tracer_init(struct trace_array *tr)
 612 {
 613         if (irqsoff_busy)
 614                 return -EBUSY;
 615
 616         save_flags = trace_flags;
 617
 618         /* non overwrite screws up the latency tracers */
 619         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 620         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 621
 622         tr->max_latency = 0;
 623         irqsoff_trace = tr;
 624         /* make sure that the tracer is visible */
 625         smp_wmb();
 626         tracing_reset_online_cpus(&tr->trace_buffer);
 627
 628         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 629
 630         /* Only toplevel instance supports graph tracing */
 631         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 632                                       is_graph())))
 633                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 634
 635         irqsoff_busy = true;
 636         return 0;
 637 }
 638
 639 static void irqsoff_tracer_reset(struct trace_array *tr)
 640 {
 641         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 642         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 643
 644         stop_irqsoff_tracer(tr, is_graph());
 645
 646         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 647         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 648         ftrace_reset_array_ops(tr);
 649
 650         irqsoff_busy = false;
 651 }
 652
 653 static void irqsoff_tracer_start(struct trace_array *tr)
 654 {
 655         tracer_enabled = 1;
 656 }
 657
 658 static void irqsoff_tracer_stop(struct trace_array *tr)
 659 {
 660         tracer_enabled = 0;
 661 }
 662
 663 #ifdef CONFIG_IRQSOFF_TRACER
 664 static int irqsoff_tracer_init(struct trace_array *tr)
 665 {
 666         trace_type = TRACER_IRQS_OFF;
 667
 668         return __irqsoff_tracer_init(tr);
 669 }
 670 static struct tracer irqsoff_tracer __read_mostly =
 671 {
 672         .name           = "irqsoff",
 673         .init           = irqsoff_tracer_init,
 674         .reset          = irqsoff_tracer_reset,
 675         .start          = irqsoff_tracer_start,
 676         .stop           = irqsoff_tracer_stop,
 677         .print_max      = true,
 678         .print_header   = irqsoff_print_header,
 679         .print_line     = irqsoff_print_line,
 680         .flags          = &tracer_flags,
 681         .set_flag       = irqsoff_set_flag,
 682         .flag_changed   = irqsoff_flag_changed,
 683 #ifdef CONFIG_FTRACE_SELFTEST
 684         .selftest    = trace_selftest_startup_irqsoff,
 685 #endif
 686         .open           = irqsoff_trace_open,
 687         .close          = irqsoff_trace_close,
 688         .allow_instances = true,
 689         .use_max_tr     = true,
 690 };
 691 # define register_irqsoff(trace) register_tracer(&trace)
 692 #else
 693 # define register_irqsoff(trace) do { } while (0)
 694 #endif
 695
 696 #ifdef CONFIG_PREEMPT_TRACER
 697 static int preemptoff_tracer_init(struct trace_array *tr)
 698 {
 699         trace_type = TRACER_PREEMPT_OFF;
 700
 701         return __irqsoff_tracer_init(tr);
 702 }
 703
 704 static struct tracer preemptoff_tracer __read_mostly =
 705 {
 706         .name           = "preemptoff",
 707         .init           = preemptoff_tracer_init,
 708         .reset          = irqsoff_tracer_reset,
 709         .start          = irqsoff_tracer_start,
 710         .stop           = irqsoff_tracer_stop,
 711         .print_max      = true,
 712         .print_header   = irqsoff_print_header,
 713         .print_line     = irqsoff_print_line,
 714         .flags          = &tracer_flags,
 715         .set_flag       = irqsoff_set_flag,
 716         .flag_changed   = irqsoff_flag_changed,
 717 #ifdef CONFIG_FTRACE_SELFTEST
 718         .selftest    = trace_selftest_startup_preemptoff,
 719 #endif
 720         .open           = irqsoff_trace_open,
 721         .close          = irqsoff_trace_close,
 722         .allow_instances = true,
 723         .use_max_tr     = true,
 724 };
 725 # define register_preemptoff(trace) register_tracer(&trace)
 726 #else
 727 # define register_preemptoff(trace) do { } while (0)
 728 #endif
 729
 730 #if defined(CONFIG_IRQSOFF_TRACER) && \
 731         defined(CONFIG_PREEMPT_TRACER)
 732
 733 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 734 {
 735         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 736
 737         return __irqsoff_tracer_init(tr);
 738 }
 739
 740 static struct tracer preemptirqsoff_tracer __read_mostly =
 741 {
 742         .name           = "preemptirqsoff",
 743         .init           = preemptirqsoff_tracer_init,
 744         .reset          = irqsoff_tracer_reset,
 745         .start          = irqsoff_tracer_start,
 746         .stop           = irqsoff_tracer_stop,
 747         .print_max      = true,
 748         .print_header   = irqsoff_print_header,
 749         .print_line     = irqsoff_print_line,
 750         .flags          = &tracer_flags,
 751         .set_flag       = irqsoff_set_flag,
 752         .flag_changed   = irqsoff_flag_changed,
 753 #ifdef CONFIG_FTRACE_SELFTEST
 754         .selftest    = trace_selftest_startup_preemptirqsoff,
 755 #endif
 756         .open           = irqsoff_trace_open,
 757         .close          = irqsoff_trace_close,
 758         .allow_instances = true,
 759         .use_max_tr     = true,
 760 };
 761
 762 # define register_preemptirqsoff(trace) register_tracer(&trace)
 763 #else
 764 # define register_preemptirqsoff(trace) do { } while (0)
 765 #endif
 766
 767 __init static int init_irqsoff_tracer(void)
 768 {
 769         register_irqsoff(irqsoff_tracer);
 770         register_preemptoff(preemptoff_tracer);
 771         register_preemptirqsoff(preemptirqsoff_tracer);
 772
 773         return 0;
 774 }
 775 core_initcall(init_irqsoff_tracer);