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         /* slight chance to get a false positive on tracing_cpu */
 114         if (!irqs_disabled_flags(*flags))
 115                 return 0;
 116
 117         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 118         disabled = atomic_inc_return(&(*data)->disabled);
 119
 120         if (likely(disabled == 1))
 121                 return 1;
 122
 123         atomic_dec(&(*data)->disabled);
 124
 125         return 0;
 126 }
 127
 128 /*
 129  * irqsoff uses its own tracer function to keep the overhead down:
 130  */
 131 static void
 132 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
 133                     struct ftrace_ops *op, struct pt_regs *pt_regs)
 134 {
 135         struct trace_array *tr = irqsoff_trace;
 136         struct trace_array_cpu *data;
 137         unsigned long flags;
 138
 139         if (!func_prolog_dec(tr, &data, &flags))
 140                 return;
 141
 142         trace_function(tr, ip, parent_ip, flags, preempt_count());
 143
 144         atomic_dec(&data->disabled);
 145 }
 146 #endif /* CONFIG_FUNCTION_TRACER */
 147
 148 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 149 static int irqsoff_display_graph(struct trace_array *tr, int set)
 150 {
 151         int cpu;
 152
 153         if (!(is_graph(tr) ^ set))
 154                 return 0;
 155
 156         stop_irqsoff_tracer(irqsoff_trace, !set);
 157
 158         for_each_possible_cpu(cpu)
 159                 per_cpu(tracing_cpu, cpu) = 0;
 160
 161         tr->max_latency = 0;
 162         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 163
 164         return start_irqsoff_tracer(irqsoff_trace, set);
 165 }
 166
 167 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 168 {
 169         struct trace_array *tr = irqsoff_trace;
 170         struct trace_array_cpu *data;
 171         unsigned long flags;
 172         int ret;
 173         int pc;
 174
 175         if (!func_prolog_dec(tr, &data, &flags))
 176                 return 0;
 177
 178         pc = preempt_count();
 179         ret = __trace_graph_entry(tr, trace, flags, pc);
 180         atomic_dec(&data->disabled);
 181
 182         return ret;
 183 }
 184
 185 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 186 {
 187         struct trace_array *tr = irqsoff_trace;
 188         struct trace_array_cpu *data;
 189         unsigned long flags;
 190         int pc;
 191
 192         if (!func_prolog_dec(tr, &data, &flags))
 193                 return;
 194
 195         pc = preempt_count();
 196         __trace_graph_return(tr, trace, flags, pc);
 197         atomic_dec(&data->disabled);
 198 }
 199
 200 static void irqsoff_trace_open(struct trace_iterator *iter)
 201 {
 202         if (is_graph(iter->tr))
 203                 graph_trace_open(iter);
 204
 205 }
 206
 207 static void irqsoff_trace_close(struct trace_iterator *iter)
 208 {
 209         if (iter->private)
 210                 graph_trace_close(iter);
 211 }
 212
 213 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 214                             TRACE_GRAPH_PRINT_PROC | \
 215                             TRACE_GRAPH_PRINT_ABS_TIME | \
 216                             TRACE_GRAPH_PRINT_DURATION)
 217
 218 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 219 {
 220         /*
 221          * In graph mode call the graph tracer output function,
 222          * otherwise go with the TRACE_FN event handler
 223          */
 224         if (is_graph(iter->tr))
 225                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 226
 227         return TRACE_TYPE_UNHANDLED;
 228 }
 229
 230 static void irqsoff_print_header(struct seq_file *s)
 231 {
 232         struct trace_array *tr = irqsoff_trace;
 233
 234         if (is_graph(tr))
 235                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 236         else
 237                 trace_default_header(s);
 238 }
 239
 240 static void
 241 __trace_function(struct trace_array *tr,
 242                  unsigned long ip, unsigned long parent_ip,
 243                  unsigned long flags, int pc)
 244 {
 245         if (is_graph(tr))
 246                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 247         else
 248                 trace_function(tr, ip, parent_ip, flags, pc);
 249 }
 250
 251 #else
 252 #define __trace_function trace_function
 253
 254 #ifdef CONFIG_FUNCTION_TRACER
 255 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 256 {
 257         return -1;
 258 }
 259 #endif
 260
 261 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 262 {
 263         return TRACE_TYPE_UNHANDLED;
 264 }
 265
 266 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 267 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 268
 269 #ifdef CONFIG_FUNCTION_TRACER
 270 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 271 static void irqsoff_print_header(struct seq_file *s)
 272 {
 273         trace_default_header(s);
 274 }
 275 #else
 276 static void irqsoff_print_header(struct seq_file *s)
 277 {
 278         trace_latency_header(s);
 279 }
 280 #endif /* CONFIG_FUNCTION_TRACER */
 281 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 282
 283 /*
 284  * Should this new latency be reported/recorded?
 285  */
 286 static bool report_latency(struct trace_array *tr, cycle_t delta)
 287 {
 288         if (tracing_thresh) {
 289                 if (delta < tracing_thresh)
 290                         return false;
 291         } else {
 292                 if (delta <= tr->max_latency)
 293                         return false;
 294         }
 295         return true;
 296 }
 297
 298 static void
 299 check_critical_timing(struct trace_array *tr,
 300                       struct trace_array_cpu *data,
 301                       unsigned long parent_ip,
 302                       int cpu)
 303 {
 304         cycle_t T0, T1, delta;
 305         unsigned long flags;
 306         int pc;
 307
 308         T0 = data->preempt_timestamp;
 309         T1 = ftrace_now(cpu);
 310         delta = T1-T0;
 311
 312         local_save_flags(flags);
 313
 314         pc = preempt_count();
 315
 316         if (!report_latency(tr, delta))
 317                 goto out;
 318
 319         raw_spin_lock_irqsave(&max_trace_lock, flags);
 320
 321         /* check if we are still the max latency */
 322         if (!report_latency(tr, delta))
 323                 goto out_unlock;
 324
 325         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 326         /* Skip 5 functions to get to the irq/preempt enable function */
 327         __trace_stack(tr, flags, 5, pc);
 328
 329         if (data->critical_sequence != max_sequence)
 330                 goto out_unlock;
 331
 332         data->critical_end = parent_ip;
 333
 334         if (likely(!is_tracing_stopped())) {
 335                 tr->max_latency = delta;
 336                 update_max_tr_single(tr, current, cpu);
 337         }
 338
 339         max_sequence++;
 340
 341 out_unlock:
 342         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 343
 344 out:
 345         data->critical_sequence = max_sequence;
 346         data->preempt_timestamp = ftrace_now(cpu);
 347         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 348 }
 349
 350 static inline void
 351 start_critical_timing(unsigned long ip, unsigned long parent_ip)
 352 {
 353         int cpu;
 354         struct trace_array *tr = irqsoff_trace;
 355         struct trace_array_cpu *data;
 356         unsigned long flags;
 357
 358         if (!tracer_enabled || !tracing_is_enabled())
 359                 return;
 360
 361         cpu = raw_smp_processor_id();
 362
 363         if (per_cpu(tracing_cpu, cpu))
 364                 return;
 365
 366         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 367
 368         if (unlikely(!data) || atomic_read(&data->disabled))
 369                 return;
 370
 371         atomic_inc(&data->disabled);
 372
 373         data->critical_sequence = max_sequence;
 374         data->preempt_timestamp = ftrace_now(cpu);
 375         data->critical_start = parent_ip ? : ip;
 376
 377         local_save_flags(flags);
 378
 379         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 380
 381         per_cpu(tracing_cpu, cpu) = 1;
 382
 383         atomic_dec(&data->disabled);
 384 }
 385
 386 static inline void
 387 stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 388 {
 389         int cpu;
 390         struct trace_array *tr = irqsoff_trace;
 391         struct trace_array_cpu *data;
 392         unsigned long flags;
 393
 394         cpu = raw_smp_processor_id();
 395         /* Always clear the tracing cpu on stopping the trace */
 396         if (unlikely(per_cpu(tracing_cpu, cpu)))
 397                 per_cpu(tracing_cpu, cpu) = 0;
 398         else
 399                 return;
 400
 401         if (!tracer_enabled || !tracing_is_enabled())
 402                 return;
 403
 404         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 405
 406         if (unlikely(!data) ||
 407             !data->critical_start || atomic_read(&data->disabled))
 408                 return;
 409
 410         atomic_inc(&data->disabled);
 411
 412         local_save_flags(flags);
 413         __trace_function(tr, ip, parent_ip, flags, preempt_count());
 414         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 415         data->critical_start = 0;
 416         atomic_dec(&data->disabled);
 417 }
 418
 419 /* start and stop critical timings used to for stoppage (in idle) */
 420 void start_critical_timings(void)
 421 {
 422         if (preempt_trace() || irq_trace())
 423                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 424         trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1);
 425 }
 426 EXPORT_SYMBOL_GPL(start_critical_timings);
 427
 428 void stop_critical_timings(void)
 429 {
 430         trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0);
 431         if (preempt_trace() || irq_trace())
 432                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 433 }
 434 EXPORT_SYMBOL_GPL(stop_critical_timings);
 435
 436 #ifdef CONFIG_IRQSOFF_TRACER
 437 #ifdef CONFIG_PROVE_LOCKING
 438 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 439 {
 440         trace_preemptirqsoff_hist_rcuidle(IRQS_ON, 0);
 441         if (!preempt_trace() && irq_trace())
 442                 stop_critical_timing(a0, a1);
 443 }
 444
 445 void time_hardirqs_off(unsigned long a0, unsigned long a1)
 446 {
 447         if (!preempt_trace() && irq_trace())
 448                 start_critical_timing(a0, a1);
 449         trace_preemptirqsoff_hist_rcuidle(IRQS_OFF, 1);
 450 }
 451
 452 #else /* !CONFIG_PROVE_LOCKING */
 453
 454 /*
 455  * Stubs:
 456  */
 457
 458 void trace_softirqs_on(unsigned long ip)
 459 {
 460 }
 461
 462 void trace_softirqs_off(unsigned long ip)
 463 {
 464 }
 465
 466 inline void print_irqtrace_events(struct task_struct *curr)
 467 {
 468 }
 469
 470 /*
 471  * We are only interested in hardirq on/off events:
 472  */
 473 void trace_hardirqs_on(void)
 474 {
 475         trace_preemptirqsoff_hist(IRQS_ON, 0);
 476         if (!preempt_trace() && irq_trace())
 477                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 478 }
 479 EXPORT_SYMBOL(trace_hardirqs_on);
 480
 481 void trace_hardirqs_off(void)
 482 {
 483         if (!preempt_trace() && irq_trace())
 484                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 485         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 486 }
 487 EXPORT_SYMBOL(trace_hardirqs_off);
 488
 489 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 490 {
 491         trace_preemptirqsoff_hist(IRQS_ON, 0);
 492         if (!preempt_trace() && irq_trace())
 493                 stop_critical_timing(CALLER_ADDR0, caller_addr);
 494 }
 495 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 496
 497 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 498 {
 499         if (!preempt_trace() && irq_trace())
 500                 start_critical_timing(CALLER_ADDR0, caller_addr);
 501         trace_preemptirqsoff_hist(IRQS_OFF, 1);
 502 }
 503 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 504
 505 #endif /* CONFIG_PROVE_LOCKING */
 506 #endif /*  CONFIG_IRQSOFF_TRACER */
 507
 508 #ifdef CONFIG_PREEMPT_TRACER
 509 void trace_preempt_on(unsigned long a0, unsigned long a1)
 510 {
 511         trace_preemptirqsoff_hist(PREEMPT_ON, 0);
 512         if (preempt_trace() && !irq_trace())
 513                 stop_critical_timing(a0, a1);
 514 }
 515
 516 void trace_preempt_off(unsigned long a0, unsigned long a1)
 517 {
 518         trace_preemptirqsoff_hist(PREEMPT_ON, 1);
 519         if (preempt_trace() && !irq_trace())
 520                 start_critical_timing(a0, a1);
 521 }
 522 #endif /* CONFIG_PREEMPT_TRACER */
 523
 524 #ifdef CONFIG_FUNCTION_TRACER
 525 static bool function_enabled;
 526
 527 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 528 {
 529         int ret;
 530
 531         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 532         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 533                 return 0;
 534
 535         if (graph)
 536                 ret = register_ftrace_graph(&irqsoff_graph_return,
 537                                             &irqsoff_graph_entry);
 538         else
 539                 ret = register_ftrace_function(tr->ops);
 540
 541         if (!ret)
 542                 function_enabled = true;
 543
 544         return ret;
 545 }
 546
 547 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 548 {
 549         if (!function_enabled)
 550                 return;
 551
 552         if (graph)
 553                 unregister_ftrace_graph();
 554         else
 555                 unregister_ftrace_function(tr->ops);
 556
 557         function_enabled = false;
 558 }
 559
 560 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 561 {
 562         if (!(mask & TRACE_ITER_FUNCTION))
 563                 return 0;
 564
 565         if (set)
 566                 register_irqsoff_function(tr, is_graph(tr), 1);
 567         else
 568                 unregister_irqsoff_function(tr, is_graph(tr));
 569         return 1;
 570 }
 571 #else
 572 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 573 {
 574         return 0;
 575 }
 576 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 577 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 578 {
 579         return 0;
 580 }
 581 #endif /* CONFIG_FUNCTION_TRACER */
 582
 583 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 584 {
 585         struct tracer *tracer = tr->current_trace;
 586
 587         if (irqsoff_function_set(tr, mask, set))
 588                 return 0;
 589
 590 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 591         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 592                 return irqsoff_display_graph(tr, set);
 593 #endif
 594
 595         return trace_keep_overwrite(tracer, mask, set);
 596 }
 597
 598 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 599 {
 600         int ret;
 601
 602         ret = register_irqsoff_function(tr, graph, 0);
 603
 604         if (!ret && tracing_is_enabled())
 605                 tracer_enabled = 1;
 606         else
 607                 tracer_enabled = 0;
 608
 609         return ret;
 610 }
 611
 612 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 613 {
 614         tracer_enabled = 0;
 615
 616         unregister_irqsoff_function(tr, graph);
 617 }
 618
 619 static bool irqsoff_busy;
 620
 621 static int __irqsoff_tracer_init(struct trace_array *tr)
 622 {
 623         if (irqsoff_busy)
 624                 return -EBUSY;
 625
 626         save_flags = tr->trace_flags;
 627
 628         /* non overwrite screws up the latency tracers */
 629         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 630         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 631
 632         tr->max_latency = 0;
 633         irqsoff_trace = tr;
 634         /* make sure that the tracer is visible */
 635         smp_wmb();
 636         tracing_reset_online_cpus(&tr->trace_buffer);
 637
 638         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 639
 640         /* Only toplevel instance supports graph tracing */
 641         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 642                                       is_graph(tr))))
 643                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 644
 645         irqsoff_busy = true;
 646         return 0;
 647 }
 648
 649 static void irqsoff_tracer_reset(struct trace_array *tr)
 650 {
 651         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 652         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 653
 654         stop_irqsoff_tracer(tr, is_graph(tr));
 655
 656         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 657         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 658         ftrace_reset_array_ops(tr);
 659
 660         irqsoff_busy = false;
 661 }
 662
 663 static void irqsoff_tracer_start(struct trace_array *tr)
 664 {
 665         tracer_enabled = 1;
 666 }
 667
 668 static void irqsoff_tracer_stop(struct trace_array *tr)
 669 {
 670         tracer_enabled = 0;
 671 }
 672
 673 #ifdef CONFIG_IRQSOFF_TRACER
 674 static int irqsoff_tracer_init(struct trace_array *tr)
 675 {
 676         trace_type = TRACER_IRQS_OFF;
 677
 678         return __irqsoff_tracer_init(tr);
 679 }
 680 static struct tracer irqsoff_tracer __read_mostly =
 681 {
 682         .name           = "irqsoff",
 683         .init           = irqsoff_tracer_init,
 684         .reset          = irqsoff_tracer_reset,
 685         .start          = irqsoff_tracer_start,
 686         .stop           = irqsoff_tracer_stop,
 687         .print_max      = true,
 688         .print_header   = irqsoff_print_header,
 689         .print_line     = irqsoff_print_line,
 690         .flag_changed   = irqsoff_flag_changed,
 691 #ifdef CONFIG_FTRACE_SELFTEST
 692         .selftest    = trace_selftest_startup_irqsoff,
 693 #endif
 694         .open           = irqsoff_trace_open,
 695         .close          = irqsoff_trace_close,
 696         .allow_instances = true,
 697         .use_max_tr     = true,
 698 };
 699 # define register_irqsoff(trace) register_tracer(&trace)
 700 #else
 701 # define register_irqsoff(trace) do { } while (0)
 702 #endif
 703
 704 #ifdef CONFIG_PREEMPT_TRACER
 705 static int preemptoff_tracer_init(struct trace_array *tr)
 706 {
 707         trace_type = TRACER_PREEMPT_OFF;
 708
 709         return __irqsoff_tracer_init(tr);
 710 }
 711
 712 static struct tracer preemptoff_tracer __read_mostly =
 713 {
 714         .name           = "preemptoff",
 715         .init           = preemptoff_tracer_init,
 716         .reset          = irqsoff_tracer_reset,
 717         .start          = irqsoff_tracer_start,
 718         .stop           = irqsoff_tracer_stop,
 719         .print_max      = true,
 720         .print_header   = irqsoff_print_header,
 721         .print_line     = irqsoff_print_line,
 722         .flag_changed   = irqsoff_flag_changed,
 723 #ifdef CONFIG_FTRACE_SELFTEST
 724         .selftest    = trace_selftest_startup_preemptoff,
 725 #endif
 726         .open           = irqsoff_trace_open,
 727         .close          = irqsoff_trace_close,
 728         .allow_instances = true,
 729         .use_max_tr     = true,
 730 };
 731 # define register_preemptoff(trace) register_tracer(&trace)
 732 #else
 733 # define register_preemptoff(trace) do { } while (0)
 734 #endif
 735
 736 #if defined(CONFIG_IRQSOFF_TRACER) && \
 737         defined(CONFIG_PREEMPT_TRACER)
 738
 739 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 740 {
 741         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 742
 743         return __irqsoff_tracer_init(tr);
 744 }
 745
 746 static struct tracer preemptirqsoff_tracer __read_mostly =
 747 {
 748         .name           = "preemptirqsoff",
 749         .init           = preemptirqsoff_tracer_init,
 750         .reset          = irqsoff_tracer_reset,
 751         .start          = irqsoff_tracer_start,
 752         .stop           = irqsoff_tracer_stop,
 753         .print_max      = true,
 754         .print_header   = irqsoff_print_header,
 755         .print_line     = irqsoff_print_line,
 756         .flag_changed   = irqsoff_flag_changed,
 757 #ifdef CONFIG_FTRACE_SELFTEST
 758         .selftest    = trace_selftest_startup_preemptirqsoff,
 759 #endif
 760         .open           = irqsoff_trace_open,
 761         .close          = irqsoff_trace_close,
 762         .allow_instances = true,
 763         .use_max_tr     = true,
 764 };
 765
 766 # define register_preemptirqsoff(trace) register_tracer(&trace)
 767 #else
 768 # define register_preemptirqsoff(trace) do { } while (0)
 769 #endif
 770
 771 __init static int init_irqsoff_tracer(void)
 772 {
 773         register_irqsoff(irqsoff_tracer);
 774         register_preemptoff(preemptoff_tracer);
 775         register_preemptirqsoff(preemptirqsoff_tracer);
 776
 777         return 0;
 778 }
 779 core_initcall(init_irqsoff_tracer);