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         if (!func_prolog_dec(tr, &data, &flags))
 212                 return;
 213
 214         pc = preempt_count();
 215         __trace_graph_return(tr, trace, flags, pc);
 216         atomic_dec(&data->disabled);
 217 }
 218
 219 static void irqsoff_trace_open(struct trace_iterator *iter)
 220 {
 221         if (is_graph(iter->tr))
 222                 graph_trace_open(iter);
 223
 224 }
 225
 226 static void irqsoff_trace_close(struct trace_iterator *iter)
 227 {
 228         if (iter->private)
 229                 graph_trace_close(iter);
 230 }
 231
 232 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 233                             TRACE_GRAPH_PRINT_PROC | \
 234                             TRACE_GRAPH_PRINT_ABS_TIME | \
 235                             TRACE_GRAPH_PRINT_DURATION)
 236
 237 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 238 {
 239         /*
 240          * In graph mode call the graph tracer output function,
 241          * otherwise go with the TRACE_FN event handler
 242          */
 243         if (is_graph(iter->tr))
 244                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 245
 246         return TRACE_TYPE_UNHANDLED;
 247 }
 248
 249 static void irqsoff_print_header(struct seq_file *s)
 250 {
 251         struct trace_array *tr = irqsoff_trace;
 252
 253         if (is_graph(tr))
 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(tr))
 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 #ifdef CONFIG_FUNCTION_TRACER
 274 static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
 275 {
 276         return -1;
 277 }
 278 #endif
 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_graph_return(struct ftrace_graph_ret *trace) { }
 290 static void irqsoff_print_header(struct seq_file *s)
 291 {
 292         trace_default_header(s);
 293 }
 294 #else
 295 static void irqsoff_print_header(struct seq_file *s)
 296 {
 297         trace_latency_header(s);
 298 }
 299 #endif /* CONFIG_FUNCTION_TRACER */
 300 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 301
 302 /*
 303  * Should this new latency be reported/recorded?
 304  */
 305 static bool report_latency(struct trace_array *tr, u64 delta)
 306 {
 307         if (tracing_thresh) {
 308                 if (delta < tracing_thresh)
 309                         return false;
 310         } else {
 311                 if (delta <= tr->max_latency)
 312                         return false;
 313         }
 314         return true;
 315 }
 316
 317 static void
 318 check_critical_timing(struct trace_array *tr,
 319                       struct trace_array_cpu *data,
 320                       unsigned long parent_ip,
 321                       int cpu)
 322 {
 323         u64 T0, T1, delta;
 324         unsigned long flags;
 325         int pc;
 326
 327         T0 = data->preempt_timestamp;
 328         T1 = ftrace_now(cpu);
 329         delta = T1-T0;
 330
 331         local_save_flags(flags);
 332
 333         pc = preempt_count();
 334
 335         if (!report_latency(tr, delta))
 336                 goto out;
 337
 338         raw_spin_lock_irqsave(&max_trace_lock, flags);
 339
 340         /* check if we are still the max latency */
 341         if (!report_latency(tr, delta))
 342                 goto out_unlock;
 343
 344         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 345         /* Skip 5 functions to get to the irq/preempt enable function */
 346         __trace_stack(tr, flags, 5, pc);
 347
 348         if (data->critical_sequence != max_sequence)
 349                 goto out_unlock;
 350
 351         data->critical_end = parent_ip;
 352
 353         if (likely(!is_tracing_stopped())) {
 354                 tr->max_latency = delta;
 355                 update_max_tr_single(tr, current, cpu);
 356         }
 357
 358         max_sequence++;
 359
 360 out_unlock:
 361         raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 362
 363 out:
 364         data->critical_sequence = max_sequence;
 365         data->preempt_timestamp = ftrace_now(cpu);
 366         __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
 367 }
 368
 369 static inline void
 370 start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 371 {
 372         int cpu;
 373         struct trace_array *tr = irqsoff_trace;
 374         struct trace_array_cpu *data;
 375         unsigned long flags;
 376
 377         if (!tracer_enabled || !tracing_is_enabled())
 378                 return;
 379
 380         cpu = raw_smp_processor_id();
 381
 382         if (per_cpu(tracing_cpu, cpu))
 383                 return;
 384
 385         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 386
 387         if (unlikely(!data) || atomic_read(&data->disabled))
 388                 return;
 389
 390         atomic_inc(&data->disabled);
 391
 392         data->critical_sequence = max_sequence;
 393         data->preempt_timestamp = ftrace_now(cpu);
 394         data->critical_start = parent_ip ? : ip;
 395
 396         local_save_flags(flags);
 397
 398         __trace_function(tr, ip, parent_ip, flags, pc);
 399
 400         per_cpu(tracing_cpu, cpu) = 1;
 401
 402         atomic_dec(&data->disabled);
 403 }
 404
 405 static inline void
 406 stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 407 {
 408         int cpu;
 409         struct trace_array *tr = irqsoff_trace;
 410         struct trace_array_cpu *data;
 411         unsigned long flags;
 412
 413         cpu = raw_smp_processor_id();
 414         /* Always clear the tracing cpu on stopping the trace */
 415         if (unlikely(per_cpu(tracing_cpu, cpu)))
 416                 per_cpu(tracing_cpu, cpu) = 0;
 417         else
 418                 return;
 419
 420         if (!tracer_enabled || !tracing_is_enabled())
 421                 return;
 422
 423         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 424
 425         if (unlikely(!data) ||
 426             !data->critical_start || atomic_read(&data->disabled))
 427                 return;
 428
 429         atomic_inc(&data->disabled);
 430
 431         local_save_flags(flags);
 432         __trace_function(tr, ip, parent_ip, flags, pc);
 433         check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 434         data->critical_start = 0;
 435         atomic_dec(&data->disabled);
 436 }
 437
 438 /* start and stop critical timings used to for stoppage (in idle) */
 439 void start_critical_timings(void)
 440 {
 441         int pc = preempt_count();
 442
 443         if (preempt_trace(pc) || irq_trace())
 444                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 445 }
 446 EXPORT_SYMBOL_GPL(start_critical_timings);
 447
 448 void stop_critical_timings(void)
 449 {
 450         int pc = preempt_count();
 451
 452         if (preempt_trace(pc) || irq_trace())
 453                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 454 }
 455 EXPORT_SYMBOL_GPL(stop_critical_timings);
 456
 457 #ifdef CONFIG_FUNCTION_TRACER
 458 static bool function_enabled;
 459
 460 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 461 {
 462         int ret;
 463
 464         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 465         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 466                 return 0;
 467
 468         if (graph)
 469                 ret = register_ftrace_graph(&irqsoff_graph_return,
 470                                             &irqsoff_graph_entry);
 471         else
 472                 ret = register_ftrace_function(tr->ops);
 473
 474         if (!ret)
 475                 function_enabled = true;
 476
 477         return ret;
 478 }
 479
 480 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 481 {
 482         if (!function_enabled)
 483                 return;
 484
 485         if (graph)
 486                 unregister_ftrace_graph();
 487         else
 488                 unregister_ftrace_function(tr->ops);
 489
 490         function_enabled = false;
 491 }
 492
 493 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 494 {
 495         if (!(mask & TRACE_ITER_FUNCTION))
 496                 return 0;
 497
 498         if (set)
 499                 register_irqsoff_function(tr, is_graph(tr), 1);
 500         else
 501                 unregister_irqsoff_function(tr, is_graph(tr));
 502         return 1;
 503 }
 504 #else
 505 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 506 {
 507         return 0;
 508 }
 509 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
 510 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
 511 {
 512         return 0;
 513 }
 514 #endif /* CONFIG_FUNCTION_TRACER */
 515
 516 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
 517 {
 518         struct tracer *tracer = tr->current_trace;
 519
 520         if (irqsoff_function_set(tr, mask, set))
 521                 return 0;
 522
 523 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 524         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 525                 return irqsoff_display_graph(tr, set);
 526 #endif
 527
 528         return trace_keep_overwrite(tracer, mask, set);
 529 }
 530
 531 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
 532 {
 533         int ret;
 534
 535         ret = register_irqsoff_function(tr, graph, 0);
 536
 537         if (!ret && tracing_is_enabled())
 538                 tracer_enabled = 1;
 539         else
 540                 tracer_enabled = 0;
 541
 542         return ret;
 543 }
 544
 545 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
 546 {
 547         tracer_enabled = 0;
 548
 549         unregister_irqsoff_function(tr, graph);
 550 }
 551
 552 static bool irqsoff_busy;
 553
 554 static int __irqsoff_tracer_init(struct trace_array *tr)
 555 {
 556         if (irqsoff_busy)
 557                 return -EBUSY;
 558
 559         save_flags = tr->trace_flags;
 560
 561         /* non overwrite screws up the latency tracers */
 562         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 563         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 564
 565         tr->max_latency = 0;
 566         irqsoff_trace = tr;
 567         /* make sure that the tracer is visible */
 568         smp_wmb();
 569
 570         ftrace_init_array_ops(tr, irqsoff_tracer_call);
 571
 572         /* Only toplevel instance supports graph tracing */
 573         if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
 574                                       is_graph(tr))))
 575                 printk(KERN_ERR "failed to start irqsoff tracer\n");
 576
 577         irqsoff_busy = true;
 578         return 0;
 579 }
 580
 581 static void __irqsoff_tracer_reset(struct trace_array *tr)
 582 {
 583         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 584         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 585
 586         stop_irqsoff_tracer(tr, is_graph(tr));
 587
 588         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 589         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 590         ftrace_reset_array_ops(tr);
 591
 592         irqsoff_busy = false;
 593 }
 594
 595 static void irqsoff_tracer_start(struct trace_array *tr)
 596 {
 597         tracer_enabled = 1;
 598 }
 599
 600 static void irqsoff_tracer_stop(struct trace_array *tr)
 601 {
 602         tracer_enabled = 0;
 603 }
 604
 605 #ifdef CONFIG_IRQSOFF_TRACER
 606 /*
 607  * We are only interested in hardirq on/off events:
 608  */
 609 void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
 610 {
 611         unsigned int pc = preempt_count();
 612
 613         if (!preempt_trace(pc) && irq_trace())
 614                 stop_critical_timing(a0, a1, pc);
 615 }
 616
 617 void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
 618 {
 619         unsigned int pc = preempt_count();
 620
 621         if (!preempt_trace(pc) && irq_trace())
 622                 start_critical_timing(a0, a1, pc);
 623 }
 624
 625 static int irqsoff_tracer_init(struct trace_array *tr)
 626 {
 627         trace_type = TRACER_IRQS_OFF;
 628
 629         return __irqsoff_tracer_init(tr);
 630 }
 631
 632 static void irqsoff_tracer_reset(struct trace_array *tr)
 633 {
 634         __irqsoff_tracer_reset(tr);
 635 }
 636
 637 static struct tracer irqsoff_tracer __read_mostly =
 638 {
 639         .name           = "irqsoff",
 640         .init           = irqsoff_tracer_init,
 641         .reset          = irqsoff_tracer_reset,
 642         .start          = irqsoff_tracer_start,
 643         .stop           = irqsoff_tracer_stop,
 644         .print_max      = true,
 645         .print_header   = irqsoff_print_header,
 646         .print_line     = irqsoff_print_line,
 647         .flag_changed   = irqsoff_flag_changed,
 648 #ifdef CONFIG_FTRACE_SELFTEST
 649         .selftest    = trace_selftest_startup_irqsoff,
 650 #endif
 651         .open           = irqsoff_trace_open,
 652         .close          = irqsoff_trace_close,
 653         .allow_instances = true,
 654         .use_max_tr     = true,
 655 };
 656 #endif /*  CONFIG_IRQSOFF_TRACER */
 657
 658 #ifdef CONFIG_PREEMPT_TRACER
 659 void tracer_preempt_on(unsigned long a0, unsigned long a1)
 660 {
 661         int pc = preempt_count();
 662
 663         if (preempt_trace(pc) && !irq_trace())
 664                 stop_critical_timing(a0, a1, pc);
 665 }
 666
 667 void tracer_preempt_off(unsigned long a0, unsigned long a1)
 668 {
 669         int pc = preempt_count();
 670
 671         if (preempt_trace(pc) && !irq_trace())
 672                 start_critical_timing(a0, a1, pc);
 673 }
 674
 675 static int preemptoff_tracer_init(struct trace_array *tr)
 676 {
 677         trace_type = TRACER_PREEMPT_OFF;
 678
 679         return __irqsoff_tracer_init(tr);
 680 }
 681
 682 static void preemptoff_tracer_reset(struct trace_array *tr)
 683 {
 684         __irqsoff_tracer_reset(tr);
 685 }
 686
 687 static struct tracer preemptoff_tracer __read_mostly =
 688 {
 689         .name           = "preemptoff",
 690         .init           = preemptoff_tracer_init,
 691         .reset          = preemptoff_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         .flag_changed   = irqsoff_flag_changed,
 698 #ifdef CONFIG_FTRACE_SELFTEST
 699         .selftest    = trace_selftest_startup_preemptoff,
 700 #endif
 701         .open           = irqsoff_trace_open,
 702         .close          = irqsoff_trace_close,
 703         .allow_instances = true,
 704         .use_max_tr     = true,
 705 };
 706 #endif /* CONFIG_PREEMPT_TRACER */
 707
 708 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 709
 710 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 711 {
 712         trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 713
 714         return __irqsoff_tracer_init(tr);
 715 }
 716
 717 static void preemptirqsoff_tracer_reset(struct trace_array *tr)
 718 {
 719         __irqsoff_tracer_reset(tr);
 720 }
 721
 722 static struct tracer preemptirqsoff_tracer __read_mostly =
 723 {
 724         .name           = "preemptirqsoff",
 725         .init           = preemptirqsoff_tracer_init,
 726         .reset          = preemptirqsoff_tracer_reset,
 727         .start          = irqsoff_tracer_start,
 728         .stop           = irqsoff_tracer_stop,
 729         .print_max      = true,
 730         .print_header   = irqsoff_print_header,
 731         .print_line     = irqsoff_print_line,
 732         .flag_changed   = irqsoff_flag_changed,
 733 #ifdef CONFIG_FTRACE_SELFTEST
 734         .selftest    = trace_selftest_startup_preemptirqsoff,
 735 #endif
 736         .open           = irqsoff_trace_open,
 737         .close          = irqsoff_trace_close,
 738         .allow_instances = true,
 739         .use_max_tr     = true,
 740 };
 741 #endif
 742
 743 __init static int init_irqsoff_tracer(void)
 744 {
 745 #ifdef CONFIG_IRQSOFF_TRACER
 746         register_tracer(&irqsoff_tracer);
 747 #endif
 748 #ifdef CONFIG_PREEMPT_TRACER
 749         register_tracer(&preemptoff_tracer);
 750 #endif
 751 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 752         register_tracer(&preemptirqsoff_tracer);
 753 #endif
 754
 755         return 0;
 756 }
 757 core_initcall(init_irqsoff_tracer);
 758 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */