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