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