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Linux/kernel/trace/trace_irqsoff.c

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  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 */
761 

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