kernel/trace/trace_irqsoff.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace irqs off critical timings
   4  *
   5  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   6  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   7  *
   8  * From code in the latency_tracer, that is:
   9  *
  10  *  Copyright (C) 2004-2006 Ingo Molnar
  11  *  Copyright (C) 2004 Nadia Yvette Chambers
  12  */
  13 #include <linux/kallsyms.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/module.h>
  16 #include <linux/ftrace.h>
  17
  18 #include "trace.h"
  19
  20 #include <trace/events/preemptirq.h>
  21
  22 #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
  23 static struct trace_array               *irqsoff_trace __read_mostly;
  24 static int                              tracer_enabled __read_mostly;
  25
  26 static DEFINE_PER_CPU(int, tracing_cpu);
  27
  28 static DEFINE_RAW_SPINLOCK(max_trace_lock);
  29
  30 enum {
  31         TRACER_IRQS_OFF         = (1 << 1),
  32         TRACER_PREEMPT_OFF      = (1 << 2),
  33 };
  34
  35 static int trace_type __read_mostly;
  36
  37 static int save_flags;
  38
  39 static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
  40 static int start_irqsoff_tracer(struct trace_array *tr, int graph);
  41
  42 #ifdef CONFIG_PREEMPT_TRACER
  43 static inline int
  44 preempt_trace(int pc)
  45 {
  46         return ((trace_type & TRACER_PREEMPT_OFF) && pc);
  47 }
  48 #else
  49 # define preempt_trace(pc) (0)
  50 #endif
  51
  52 #ifdef CONFIG_IRQSOFF_TRACER
  53 static inline int
  54 irq_trace(void)
  55 {
  56         return ((trace_type & TRACER_IRQS_OFF) &&
  57                 irqs_disabled());
  58 }
  59 #else
  60 # define irq_trace() (0)
  61 #endif
  62
  63 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  64 static int irqsoff_display_graph(struct trace_array *tr, int set);
  65 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
  66 #else
  67 static inline int irqsoff_display_graph(struct trace_array *tr, int set)
  68 {
  69         return -EINVAL;
  70 }
  71 # define is_graph(tr) false
  72 #endif
  73
  74 /*
  75  * Sequence count - we record it when starting a measurement and
  76  * skip the latency if the sequence has changed - some other section
  77  * did a maximum and could disturb our measurement with serial console
  78  * printouts, etc. Truly coinciding maximum latencies should be rare
  79  * and what happens together happens separately as well, so this doesn't
  80  * decrease the validity of the maximum found:
  81  */
  82 static __cacheline_aligned_in_smp       unsigned long max_sequence;
  83
  84 #ifdef CONFIG_FUNCTION_TRACER
  85 /*
  86  * Prologue for the preempt and irqs off function tracers.
  87  *
  88  * Returns 1 if it is OK to continue, and data->disabled is
  89  *            incremented.
  90  *         0 if the trace is to be ignored, and data->disabled
  91  *            is kept the same.
  92  *
  93  * Note, this function is also used outside this ifdef but
  94  *  inside the #ifdef of the function graph tracer below.
  95  *  This is OK, since the function graph tracer is
  96  *  dependent on the function tracer.
  97  */
  98 static int func_prolog_dec(struct trace_array *tr,
  99                            struct trace_array_cpu **data,
 100                            unsigned long *flags)
 101 {
 102         long disabled;
 103         int cpu;
 104
 105         /*
 106          * Does not matter if we preempt. We test the flags
 107          * afterward, to see if irqs are disabled or not.
 108          * If we preempt and get a false positive, the flags
 109          * test will fail.
 110          */
 111         cpu = raw_smp_processor_id();
 112         if (likely(!per_cpu(tracing_cpu, cpu)))
 113                 return 0;
 114
 115         local_save_flags(*flags);
 116         /*
 117          * Slight chance to get a false positive on tracing_cpu,
 118          * although I'm starting to think there isn't a chance.
 119          * Leave this for now just to be paranoid.
 120          */
 121         if (!irqs_disabled_flags(*flags) && !preempt_count())
 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 irqsoff_display_graph(struct trace_array *tr, int set)
 157 {
 158         int cpu;
 159
 160         if (!(is_graph(tr) ^ set))
 161                 return 0;
 162
 163         stop_irqsoff_tracer(irqsoff_trace, !set);
 164
 165         for_each_possible_cpu(cpu)
 166                 per_cpu(tracing_cpu, cpu) = 0;
 167
 168         tr->max_latency = 0;
 169         tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);
 170
 171         return start_irqsoff_tracer(irqsoff_trace, set);
 172 }
 173
 174 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 175 {
 176         struct trace_array *tr = irqsoff_trace;
 177         struct trace_array_cpu *data;
 178         unsigned long flags;
 179         int ret;
 180         int pc;
 181
 182         if (ftrace_graph_ignore_func(trace))
 183                 return 0;
 184         /*
 185          * Do not trace a function if it's filtered by set_graph_notrace.
 186          * Make the index of ret stack negative to indicate that it should
 187          * ignore further functions.  But it needs its own ret stack entry
 188          * to recover the original index in order to continue tracing after
 189          * returning from the function.
 190          */
 191         if (ftrace_graph_notrace_addr(trace->func))
 192                 return 1;
 193
 194         if (!func_prolog_dec(tr, &data, &flags))
 195                 return 0;
 196
 197         pc = preempt_count();
 198         ret = __trace_graph_entry(tr, trace, flags, pc);
 199         atomic_dec(&data->disabled);
 200
 201         return ret;
 202 }
 203
 204 static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 205 {
 206         struct trace_array *tr = irqsoff_trace;
 207         struct trace_array_cpu *data;
 208         unsigned long flags;
 209         int pc;
 210
 211         ftrace_graph_addr_finish(trace);
 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 struct fgraph_ops fgraph_ops = {
 222         .entryfunc              = &irqsoff_graph_entry,
 223         .retfunc                = &irqsoff_graph_return,
 224 };
 225
 226 static void irqsoff_trace_open(struct trace_iterator *iter)
 227 {
 228         if (is_graph(iter->tr))
 229                 graph_trace_open(iter);
 230
 231 }
 232
 233 static void irqsoff_trace_close(struct trace_iterator *iter)
 234 {
 235         if (iter->private)
 236                 graph_trace_close(iter);
 237 }
 238
 239 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 240                             TRACE_GRAPH_PRINT_PROC | \
 241                             TRACE_GRAPH_PRINT_ABS_TIME | \
 242                             TRACE_GRAPH_PRINT_DURATION)
 243
 244 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 245 {
 246         /*
 247          * In graph mode call the graph tracer output function,
 248          * otherwise go with the TRACE_FN event handler
 249          */
 250         if (is_graph(iter->tr))
 251                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 252
 253         return TRACE_TYPE_UNHANDLED;
 254 }
 255
 256 static void irqsoff_print_header(struct seq_file *s)
 257 {
 258         struct trace_array *tr = irqsoff_trace;
 259
 260         if (is_graph(tr))
 261                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 262         else
 263                 trace_default_header(s);
 264 }
 265
 266 static void
 267 __trace_function(struct trace_array *tr,
 268                  unsigned long ip, unsigned long parent_ip,
 269                  unsigned long flags, int pc)
 270 {
 271         if (is_graph(tr))
 272                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 273         else
 274                 trace_function(tr, ip, parent_ip, flags, pc);
 275 }
 276
 277 #else
 278 #define __trace_function trace_function
 279
 280 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 281 {
 282         return TRACE_TYPE_UNHANDLED;
 283 }
 284
 285 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 286 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 287
 288 #ifdef CONFIG_FUNCTION_TRACER
 289 static void irqsoff_print_header(struct seq_file *s)
 290 {
 291         trace_default_header(s);
 292 }
 293 #else
 294 static void irqsoff_print_header(struct seq_file *s)
 295 {
 296         trace_latency_header(s);
 297 }
 298 #endif /* CONFIG_FUNCTION_TRACER */
 299 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 300
 301 /*
 302  * Should this new latency be reported/recorded?
 303  */
 304 static bool report_latency(struct trace_array *tr, u64 delta)
 305 {
 306         if (tracing_thresh) {
 307                 if (delta < tracing_thresh)
 308                         return false;
 309         } else {
 310                 if (delta <= tr->max_latency)
 311                         return false;
 312         }
 313         return true;
 314 }
 315
 316 static void
 317 check_critical_timing(struct trace_array *tr,
 318                       struct trace_array_cpu *data,
 319                       unsigned long parent_ip,
 320                       int cpu)
 321 {
 322         u64 T0, T1, delta;
 323         unsigned long flags;
 324         int pc;
 325
 326         T0 = data->preempt_timestamp;
 327         T1 = ftrace_now(cpu);
 328         delta = T1-T0;
 329
 330         local_save_flags(flags);
 331
 332         pc = preempt_count();
 333
 334         if (!report_latency(tr, delta))
 335                 goto out;
 336
 337         raw_spin_lock_irqsave(&max_trace_lock, flags);
 338
 339         /* check if we are still the max latency */
 340         if (!report_latency(tr, delta))
 341                 goto out_unlock;
 342
 343         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 344         /* Skip 5 functions to get to the irq/preempt enable function */
 345         __trace_stack(tr, flags, 5, pc);
 346
 347         if (data->critical_sequence != max_sequence)
 348                 goto out_unlock;
 349
 350         data->critical_end = parent_ip;
 351
 352         if (likely(!is_tracing_stopped())) {
 353                 tr->max_latency = delta;
 354                 update_max_tr_single(tr, current, cpu);
 355         }
 356
 357         max_sequence++;
 358
 359 out_unlock:
 360         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 361
 362 out:
 363         data->critical_sequence = max_sequence;
 364         data->preempt_timestamp = ftrace_now(cpu);
 365         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 366 }
 367
 368 static inline void
 369 start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 370 {
 371         int cpu;
 372         struct trace_array *tr = irqsoff_trace;
 373         struct trace_array_cpu *data;
 374         unsigned long flags;
 375
 376         if (!tracer_enabled || !tracing_is_enabled())
 377                 return;
 378
 379         cpu = raw_smp_processor_id();
 380
 381         if (per_cpu(tracing_cpu, cpu))
 382                 return;
 383
 384         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 385
 386         if (unlikely(!data) || atomic_read(&data->disabled))
 387                 return;
 388
 389         atomic_inc(&data->disabled);
 390
 391         data->critical_sequence = max_sequence;
 392         data->preempt_timestamp = ftrace_now(cpu);
 393         data->critical_start = parent_ip ? : ip;
 394
 395         local_save_flags(flags);
 396
 397         __trace_function(tr, ip, parent_ip, flags, pc);
 398
 399         per_cpu(tracing_cpu, cpu) = 1;
 400
 401         atomic_dec(&data->disabled);
 402 }
 403
 404 static inline void
 405 stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 406 {
 407         int cpu;
 408         struct trace_array *tr = irqsoff_trace;
 409         struct trace_array_cpu *data;
 410         unsigned long flags;
 411
 412         cpu = raw_smp_processor_id();
 413         /* Always clear the tracing cpu on stopping the trace */
 414         if (unlikely(per_cpu(tracing_cpu, cpu)))
 415                 per_cpu(tracing_cpu, cpu) = 0;
 416         else
 417                 return;
 418
 419         if (!tracer_enabled || !tracing_is_enabled())
 420                 return;
 421
 422         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 423
 424         if (unlikely(!data) ||
 425             !data->critical_start || atomic_read(&data->disabled))
 426                 return;
 427
 428         atomic_inc(&data->disabled);
 429
 430         local_save_flags(flags);
 431         __trace_function(tr, ip, parent_ip, flags, pc);
 432         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 433         data->critical_start = 0;
 434         atomic_dec(&data->disabled);
 435 }
 436
 437 /* start and stop critical timings used to for stoppage (in idle) */
 438 void start_critical_timings(void)
 439 {
 440         int pc = preempt_count();
 441
 442         if (preempt_trace(pc) || irq_trace())
 443                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 444 }
 445 EXPORT_SYMBOL_GPL(start_critical_timings);
 446
 447 void stop_critical_timings(void)
 448 {
 449         int pc = preempt_count();
 450
 451         if (preempt_trace(pc) || irq_trace())
 452                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 453 }
 454 EXPORT_SYMBOL_GPL(stop_critical_timings);
 455
 456 #ifdef CONFIG_FUNCTION_TRACER
 457 static bool function_enabled;
 458
 459 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 460 {
 461         int ret;
 462
 463         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 464         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 465                 return 0;
 466
 467         if (graph)
 468                 ret = register_ftrace_graph(&fgraph_ops);
 469         else
 470                 ret = register_ftrace_function(tr->ops);
 471
 472         if (!ret)
 473                 function_enabled = true;
 474
 475         return ret;
 476 }
 477
 478 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 479 {
 480         if (!function_enabled)
 481                 return;
 482
 483         if (graph)
 484                 unregister_ftrace_graph(&fgraph_ops);
 485         else
 486                 unregister_ftrace_function(tr->ops);
 487
 488         function_enabled = false;
 489 }
 490
 491 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 492 {
 493         if (!(mask & TRACE_ITER_FUNCTION))
 494                 return 0;
 495
 496         if (set)
 497                 register_irqsoff_function(tr, is_graph(tr), 1);
 498         else
 499                 unregister_irqsoff_function(tr, is_graph(tr));
 500         return 1;
 501 }
 502 #else
 503 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 504 {
 505         return 0;
 506 }
 507 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 508 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 509 {
 510         return 0;
 511 }
 512 #endif /* CONFIG_FUNCTION_TRACER */
 513
 514 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 515 {
 516         struct tracer *tracer = tr->current_trace;
 517
 518         if (irqsoff_function_set(tr, mask, set))
 519                 return 0;
 520
 521 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 522         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 523                 return irqsoff_display_graph(tr, set);
 524 #endif
 525
 526         return trace_keep_overwrite(tracer, mask, set);
 527 }
 528
 529 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 530 {
 531         int ret;
 532
 533         ret = register_irqsoff_function(tr, graph, 0);
 534
 535         if (!ret && tracing_is_enabled())
 536                 tracer_enabled = 1;
 537         else
 538                 tracer_enabled = 0;
 539
 540         return ret;
 541 }
 542
 543 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 544 {
 545         tracer_enabled = 0;
 546
 547         unregister_irqsoff_function(tr, graph);
 548 }
 549
 550 static bool irqsoff_busy;
 551
 552 static int __irqsoff_tracer_init(struct trace_array *tr)
 553 {
 554         if (irqsoff_busy)
 555                 return -EBUSY;
 556
 557         save_flags = tr->trace_flags;
 558
 559         /* non overwrite screws up the latency tracers */
 560         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 561         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 562
 563         tr->max_latency = 0;
 564         irqsoff_trace = tr;
 565         /* make sure that the tracer is visible */
 566         smp_wmb();
 567
 568         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 569
 570         /* Only toplevel instance supports graph tracing */
 571         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 572                                       is_graph(tr))))
 573                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 574
 575         irqsoff_busy = true;
 576         return 0;
 577 }
 578
 579 static void __irqsoff_tracer_reset(struct trace_array *tr)
 580 {
 581         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 582         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 583
 584         stop_irqsoff_tracer(tr, is_graph(tr));
 585
 586         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 587         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 588         ftrace_reset_array_ops(tr);
 589
 590         irqsoff_busy = false;
 591 }
 592
 593 static void irqsoff_tracer_start(struct trace_array *tr)
 594 {
 595         tracer_enabled = 1;
 596 }
 597
 598 static void irqsoff_tracer_stop(struct trace_array *tr)
 599 {
 600         tracer_enabled = 0;
 601 }
 602
 603 #ifdef CONFIG_IRQSOFF_TRACER
 604 /*
 605  * We are only interested in hardirq on/off events:
 606  */
 607 void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
 608 {
 609         unsigned int pc = preempt_count();
 610
 611         if (!preempt_trace(pc) && irq_trace())
 612                 stop_critical_timing(a0, a1, pc);
 613 }
 614
 615 void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
 616 {
 617         unsigned int pc = preempt_count();
 618
 619         if (!preempt_trace(pc) && irq_trace())
 620                 start_critical_timing(a0, a1, pc);
 621 }
 622
 623 static int irqsoff_tracer_init(struct trace_array *tr)
 624 {
 625         trace_type = TRACER_IRQS_OFF;
 626
 627         return __irqsoff_tracer_init(tr);
 628 }
 629
 630 static void irqsoff_tracer_reset(struct trace_array *tr)
 631 {
 632         __irqsoff_tracer_reset(tr);
 633 }
 634
 635 static struct tracer irqsoff_tracer __read_mostly =
 636 {
 637         .name           = "irqsoff",
 638         .init           = irqsoff_tracer_init,
 639         .reset          = irqsoff_tracer_reset,
 640         .start          = irqsoff_tracer_start,
 641         .stop           = irqsoff_tracer_stop,
 642         .print_max      = true,
 643         .print_header   = irqsoff_print_header,
 644         .print_line     = irqsoff_print_line,
 645         .flag_changed   = irqsoff_flag_changed,
 646 #ifdef CONFIG_FTRACE_SELFTEST
 647         .selftest    = trace_selftest_startup_irqsoff,
 648 #endif
 649         .open           = irqsoff_trace_open,
 650         .close          = irqsoff_trace_close,
 651         .allow_instances = true,
 652         .use_max_tr     = true,
 653 };
 654 #endif /*  CONFIG_IRQSOFF_TRACER */
 655
 656 #ifdef CONFIG_PREEMPT_TRACER
 657 void tracer_preempt_on(unsigned long a0, unsigned long a1)
 658 {
 659         int pc = preempt_count();
 660
 661         if (preempt_trace(pc) && !irq_trace())
 662                 stop_critical_timing(a0, a1, pc);
 663 }
 664
 665 void tracer_preempt_off(unsigned long a0, unsigned long a1)
 666 {
 667         int pc = preempt_count();
 668
 669         if (preempt_trace(pc) && !irq_trace())
 670                 start_critical_timing(a0, a1, pc);
 671 }
 672
 673 static int preemptoff_tracer_init(struct trace_array *tr)
 674 {
 675         trace_type = TRACER_PREEMPT_OFF;
 676
 677         return __irqsoff_tracer_init(tr);
 678 }
 679
 680 static void preemptoff_tracer_reset(struct trace_array *tr)
 681 {
 682         __irqsoff_tracer_reset(tr);
 683 }
 684
 685 static struct tracer preemptoff_tracer __read_mostly =
 686 {
 687         .name           = "preemptoff",
 688         .init           = preemptoff_tracer_init,
 689         .reset          = preemptoff_tracer_reset,
 690         .start          = irqsoff_tracer_start,
 691         .stop           = irqsoff_tracer_stop,
 692         .print_max      = true,
 693         .print_header   = irqsoff_print_header,
 694         .print_line     = irqsoff_print_line,
 695         .flag_changed   = irqsoff_flag_changed,
 696 #ifdef CONFIG_FTRACE_SELFTEST
 697         .selftest    = trace_selftest_startup_preemptoff,
 698 #endif
 699         .open           = irqsoff_trace_open,
 700         .close          = irqsoff_trace_close,
 701         .allow_instances = true,
 702         .use_max_tr     = true,
 703 };
 704 #endif /* CONFIG_PREEMPT_TRACER */
 705
 706 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 707
 708 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 709 {
 710         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 711
 712         return __irqsoff_tracer_init(tr);
 713 }
 714
 715 static void preemptirqsoff_tracer_reset(struct trace_array *tr)
 716 {
 717         __irqsoff_tracer_reset(tr);
 718 }
 719
 720 static struct tracer preemptirqsoff_tracer __read_mostly =
 721 {
 722         .name           = "preemptirqsoff",
 723         .init           = preemptirqsoff_tracer_init,
 724         .reset          = preemptirqsoff_tracer_reset,
 725         .start          = irqsoff_tracer_start,
 726         .stop           = irqsoff_tracer_stop,
 727         .print_max      = true,
 728         .print_header   = irqsoff_print_header,
 729         .print_line     = irqsoff_print_line,
 730         .flag_changed   = irqsoff_flag_changed,
 731 #ifdef CONFIG_FTRACE_SELFTEST
 732         .selftest    = trace_selftest_startup_preemptirqsoff,
 733 #endif
 734         .open           = irqsoff_trace_open,
 735         .close          = irqsoff_trace_close,
 736         .allow_instances = true,
 737         .use_max_tr     = true,
 738 };
 739 #endif
 740
 741 __init static int init_irqsoff_tracer(void)
 742 {
 743 #ifdef CONFIG_IRQSOFF_TRACER
 744         register_tracer(&irqsoff_tracer);
 745 #endif
 746 #ifdef CONFIG_PREEMPT_TRACER
 747         register_tracer(&preemptoff_tracer);
 748 #endif
 749 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 750         register_tracer(&preemptirqsoff_tracer);
 751 #endif
 752
 753         return 0;
 754 }
 755 core_initcall(init_irqsoff_tracer);
 756 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */