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 void irqsoff_trace_open(struct trace_iterator *iter)
 222 {
 223         if (is_graph(iter->tr))
 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(iter->tr))
 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         struct trace_array *tr = irqsoff_trace;
 254
 255         if (is_graph(tr))
 256                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 257         else
 258                 trace_default_header(s);
 259 }
 260
 261 static void
 262 __trace_function(struct trace_array *tr,
 263                  unsigned long ip, unsigned long parent_ip,
 264                  unsigned long flags, int pc)
 265 {
 266         if (is_graph(tr))
 267                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 268         else
 269                 trace_function(tr, ip, parent_ip, flags, pc);
 270 }
 271
 272 #else
 273 #define __trace_function trace_function
 274
 275 #ifdef CONFIG_FUNCTION_TRACER
 276 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 277 {
 278         return -1;
 279 }
 280 #endif
 281
 282 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 283 {
 284         return TRACE_TYPE_UNHANDLED;
 285 }
 286
 287 static void irqsoff_trace_open(struct trace_iterator *iter) { }
 288 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 289
 290 #ifdef CONFIG_FUNCTION_TRACER
 291 static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 292 static void irqsoff_print_header(struct seq_file *s)
 293 {
 294         trace_default_header(s);
 295 }
 296 #else
 297 static void irqsoff_print_header(struct seq_file *s)
 298 {
 299         trace_latency_header(s);
 300 }
 301 #endif /* CONFIG_FUNCTION_TRACER */
 302 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 303
 304 /*
 305  * Should this new latency be reported/recorded?
 306  */
 307 static bool report_latency(struct trace_array *tr, u64 delta)
 308 {
 309         if (tracing_thresh) {
 310                 if (delta < tracing_thresh)
 311                         return false;
 312         } else {
 313                 if (delta <= tr->max_latency)
 314                         return false;
 315         }
 316         return true;
 317 }
 318
 319 static void
 320 check_critical_timing(struct trace_array *tr,
 321                       struct trace_array_cpu *data,
 322                       unsigned long parent_ip,
 323                       int cpu)
 324 {
 325         u64 T0, T1, delta;
 326         unsigned long flags;
 327         int pc;
 328
 329         T0 = data->preempt_timestamp;
 330         T1 = ftrace_now(cpu);
 331         delta = T1-T0;
 332
 333         local_save_flags(flags);
 334
 335         pc = preempt_count();
 336
 337         if (!report_latency(tr, delta))
 338                 goto out;
 339
 340         raw_spin_lock_irqsave(&max_trace_lock, flags);
 341
 342         /* check if we are still the max latency */
 343         if (!report_latency(tr, delta))
 344                 goto out_unlock;
 345
 346         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 347         /* Skip 5 functions to get to the irq/preempt enable function */
 348         __trace_stack(tr, flags, 5, pc);
 349
 350         if (data->critical_sequence != max_sequence)
 351                 goto out_unlock;
 352
 353         data->critical_end = parent_ip;
 354
 355         if (likely(!is_tracing_stopped())) {
 356                 tr->max_latency = delta;
 357                 update_max_tr_single(tr, current, cpu);
 358         }
 359
 360         max_sequence++;
 361
 362 out_unlock:
 363         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 364
 365 out:
 366         data->critical_sequence = max_sequence;
 367         data->preempt_timestamp = ftrace_now(cpu);
 368         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 369 }
 370
 371 static inline void
 372 start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 373 {
 374         int cpu;
 375         struct trace_array *tr = irqsoff_trace;
 376         struct trace_array_cpu *data;
 377         unsigned long flags;
 378
 379         if (!tracer_enabled || !tracing_is_enabled())
 380                 return;
 381
 382         cpu = raw_smp_processor_id();
 383
 384         if (per_cpu(tracing_cpu, cpu))
 385                 return;
 386
 387         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 388
 389         if (unlikely(!data) || atomic_read(&data->disabled))
 390                 return;
 391
 392         atomic_inc(&data->disabled);
 393
 394         data->critical_sequence = max_sequence;
 395         data->preempt_timestamp = ftrace_now(cpu);
 396         data->critical_start = parent_ip ? : ip;
 397
 398         local_save_flags(flags);
 399
 400         __trace_function(tr, ip, parent_ip, flags, pc);
 401
 402         per_cpu(tracing_cpu, cpu) = 1;
 403
 404         atomic_dec(&data->disabled);
 405 }
 406
 407 static inline void
 408 stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 409 {
 410         int cpu;
 411         struct trace_array *tr = irqsoff_trace;
 412         struct trace_array_cpu *data;
 413         unsigned long flags;
 414
 415         cpu = raw_smp_processor_id();
 416         /* Always clear the tracing cpu on stopping the trace */
 417         if (unlikely(per_cpu(tracing_cpu, cpu)))
 418                 per_cpu(tracing_cpu, cpu) = 0;
 419         else
 420                 return;
 421
 422         if (!tracer_enabled || !tracing_is_enabled())
 423                 return;
 424
 425         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 426
 427         if (unlikely(!data) ||
 428             !data->critical_start || atomic_read(&data->disabled))
 429                 return;
 430
 431         atomic_inc(&data->disabled);
 432
 433         local_save_flags(flags);
 434         __trace_function(tr, ip, parent_ip, flags, pc);
 435         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 436         data->critical_start = 0;
 437         atomic_dec(&data->disabled);
 438 }
 439
 440 /* start and stop critical timings used to for stoppage (in idle) */
 441 void start_critical_timings(void)
 442 {
 443         int pc = preempt_count();
 444
 445         if (preempt_trace(pc) || irq_trace())
 446                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 447 }
 448 EXPORT_SYMBOL_GPL(start_critical_timings);
 449
 450 void stop_critical_timings(void)
 451 {
 452         int pc = preempt_count();
 453
 454         if (preempt_trace(pc) || irq_trace())
 455                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 456 }
 457 EXPORT_SYMBOL_GPL(stop_critical_timings);
 458
 459 #ifdef CONFIG_FUNCTION_TRACER
 460 static bool function_enabled;
 461
 462 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 463 {
 464         int ret;
 465
 466         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 467         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 468                 return 0;
 469
 470         if (graph)
 471                 ret = register_ftrace_graph(&irqsoff_graph_return,
 472                                             &irqsoff_graph_entry);
 473         else
 474                 ret = register_ftrace_function(tr->ops);
 475
 476         if (!ret)
 477                 function_enabled = true;
 478
 479         return ret;
 480 }
 481
 482 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 483 {
 484         if (!function_enabled)
 485                 return;
 486
 487         if (graph)
 488                 unregister_ftrace_graph();
 489         else
 490                 unregister_ftrace_function(tr->ops);
 491
 492         function_enabled = false;
 493 }
 494
 495 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 496 {
 497         if (!(mask & TRACE_ITER_FUNCTION))
 498                 return 0;
 499
 500         if (set)
 501                 register_irqsoff_function(tr, is_graph(tr), 1);
 502         else
 503                 unregister_irqsoff_function(tr, is_graph(tr));
 504         return 1;
 505 }
 506 #else
 507 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 508 {
 509         return 0;
 510 }
 511 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 512 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 513 {
 514         return 0;
 515 }
 516 #endif /* CONFIG_FUNCTION_TRACER */
 517
 518 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 519 {
 520         struct tracer *tracer = tr->current_trace;
 521
 522         if (irqsoff_function_set(tr, mask, set))
 523                 return 0;
 524
 525 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 526         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 527                 return irqsoff_display_graph(tr, set);
 528 #endif
 529
 530         return trace_keep_overwrite(tracer, mask, set);
 531 }
 532
 533 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 534 {
 535         int ret;
 536
 537         ret = register_irqsoff_function(tr, graph, 0);
 538
 539         if (!ret && tracing_is_enabled())
 540                 tracer_enabled = 1;
 541         else
 542                 tracer_enabled = 0;
 543
 544         return ret;
 545 }
 546
 547 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 548 {
 549         tracer_enabled = 0;
 550
 551         unregister_irqsoff_function(tr, graph);
 552 }
 553
 554 static bool irqsoff_busy;
 555
 556 static int __irqsoff_tracer_init(struct trace_array *tr)
 557 {
 558         if (irqsoff_busy)
 559                 return -EBUSY;
 560
 561         save_flags = tr->trace_flags;
 562
 563         /* non overwrite screws up the latency tracers */
 564         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 565         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 566
 567         tr->max_latency = 0;
 568         irqsoff_trace = tr;
 569         /* make sure that the tracer is visible */
 570         smp_wmb();
 571
 572         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 573
 574         /* Only toplevel instance supports graph tracing */
 575         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 576                                       is_graph(tr))))
 577                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 578
 579         irqsoff_busy = true;
 580         return 0;
 581 }
 582
 583 static void __irqsoff_tracer_reset(struct trace_array *tr)
 584 {
 585         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 586         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 587
 588         stop_irqsoff_tracer(tr, is_graph(tr));
 589
 590         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 591         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 592         ftrace_reset_array_ops(tr);
 593
 594         irqsoff_busy = false;
 595 }
 596
 597 static void irqsoff_tracer_start(struct trace_array *tr)
 598 {
 599         tracer_enabled = 1;
 600 }
 601
 602 static void irqsoff_tracer_stop(struct trace_array *tr)
 603 {
 604         tracer_enabled = 0;
 605 }
 606
 607 #ifdef CONFIG_IRQSOFF_TRACER
 608 /*
 609  * We are only interested in hardirq on/off events:
 610  */
 611 void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
 612 {
 613         unsigned int pc = preempt_count();
 614
 615         if (!preempt_trace(pc) && irq_trace())
 616                 stop_critical_timing(a0, a1, pc);
 617 }
 618
 619 void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
 620 {
 621         unsigned int pc = preempt_count();
 622
 623         if (!preempt_trace(pc) && irq_trace())
 624                 start_critical_timing(a0, a1, pc);
 625 }
 626
 627 static int irqsoff_tracer_init(struct trace_array *tr)
 628 {
 629         trace_type = TRACER_IRQS_OFF;
 630
 631         return __irqsoff_tracer_init(tr);
 632 }
 633
 634 static void irqsoff_tracer_reset(struct trace_array *tr)
 635 {
 636         __irqsoff_tracer_reset(tr);
 637 }
 638
 639 static struct tracer irqsoff_tracer __read_mostly =
 640 {
 641         .name           = "irqsoff",
 642         .init           = irqsoff_tracer_init,
 643         .reset          = irqsoff_tracer_reset,
 644         .start          = irqsoff_tracer_start,
 645         .stop           = irqsoff_tracer_stop,
 646         .print_max      = true,
 647         .print_header   = irqsoff_print_header,
 648         .print_line     = irqsoff_print_line,
 649         .flag_changed   = irqsoff_flag_changed,
 650 #ifdef CONFIG_FTRACE_SELFTEST
 651         .selftest    = trace_selftest_startup_irqsoff,
 652 #endif
 653         .open           = irqsoff_trace_open,
 654         .close          = irqsoff_trace_close,
 655         .allow_instances = true,
 656         .use_max_tr     = true,
 657 };
 658 #endif /*  CONFIG_IRQSOFF_TRACER */
 659
 660 #ifdef CONFIG_PREEMPT_TRACER
 661 void tracer_preempt_on(unsigned long a0, unsigned long a1)
 662 {
 663         int pc = preempt_count();
 664
 665         if (preempt_trace(pc) && !irq_trace())
 666                 stop_critical_timing(a0, a1, pc);
 667 }
 668
 669 void tracer_preempt_off(unsigned long a0, unsigned long a1)
 670 {
 671         int pc = preempt_count();
 672
 673         if (preempt_trace(pc) && !irq_trace())
 674                 start_critical_timing(a0, a1, pc);
 675 }
 676
 677 static int preemptoff_tracer_init(struct trace_array *tr)
 678 {
 679         trace_type = TRACER_PREEMPT_OFF;
 680
 681         return __irqsoff_tracer_init(tr);
 682 }
 683
 684 static void preemptoff_tracer_reset(struct trace_array *tr)
 685 {
 686         __irqsoff_tracer_reset(tr);
 687 }
 688
 689 static struct tracer preemptoff_tracer __read_mostly =
 690 {
 691         .name           = "preemptoff",
 692         .init           = preemptoff_tracer_init,
 693         .reset          = preemptoff_tracer_reset,
 694         .start          = irqsoff_tracer_start,
 695         .stop           = irqsoff_tracer_stop,
 696         .print_max      = true,
 697         .print_header   = irqsoff_print_header,
 698         .print_line     = irqsoff_print_line,
 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         .allow_instances = true,
 706         .use_max_tr     = true,
 707 };
 708 #endif /* CONFIG_PREEMPT_TRACER */
 709
 710 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 711
 712 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 713 {
 714         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 715
 716         return __irqsoff_tracer_init(tr);
 717 }
 718
 719 static void preemptirqsoff_tracer_reset(struct trace_array *tr)
 720 {
 721         __irqsoff_tracer_reset(tr);
 722 }
 723
 724 static struct tracer preemptirqsoff_tracer __read_mostly =
 725 {
 726         .name           = "preemptirqsoff",
 727         .init           = preemptirqsoff_tracer_init,
 728         .reset          = preemptirqsoff_tracer_reset,
 729         .start          = irqsoff_tracer_start,
 730         .stop           = irqsoff_tracer_stop,
 731         .print_max      = true,
 732         .print_header   = irqsoff_print_header,
 733         .print_line     = irqsoff_print_line,
 734         .flag_changed   = irqsoff_flag_changed,
 735 #ifdef CONFIG_FTRACE_SELFTEST
 736         .selftest    = trace_selftest_startup_preemptirqsoff,
 737 #endif
 738         .open           = irqsoff_trace_open,
 739         .close          = irqsoff_trace_close,
 740         .allow_instances = true,
 741         .use_max_tr     = true,
 742 };
 743 #endif
 744
 745 __init static int init_irqsoff_tracer(void)
 746 {
 747 #ifdef CONFIG_IRQSOFF_TRACER
 748         register_tracer(&irqsoff_tracer);
 749 #endif
 750 #ifdef CONFIG_PREEMPT_TRACER
 751         register_tracer(&preemptoff_tracer);
 752 #endif
 753 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 754         register_tracer(&preemptirqsoff_tracer);
 755 #endif
 756
 757         return 0;
 758 }
 759 core_initcall(init_irqsoff_tracer);
 760 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */