xref: /openbmc/linux/kernel/trace/trace_irqsoff.c (revision addee42a)
1 /*
2  * trace irqs off critical timings
3  *
4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6  *
7  * From code in the latency_tracer, that is:
8  *
9  *  Copyright (C) 2004-2006 Ingo Molnar
10  *  Copyright (C) 2004 Nadia Yvette Chambers
11  */
12 #include <linux/kallsyms.h>
13 #include <linux/uaccess.h>
14 #include <linux/module.h>
15 #include <linux/ftrace.h>
16 
17 #include "trace.h"
18 
19 #define CREATE_TRACE_POINTS
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(void)
45 {
46 	return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
47 }
48 #else
49 # define preempt_trace() (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)
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, preempt_count());
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)
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, preempt_count());
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 	if (preempt_trace() || irq_trace())
442 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
443 }
444 EXPORT_SYMBOL_GPL(start_critical_timings);
445 
446 void stop_critical_timings(void)
447 {
448 	if (preempt_trace() || irq_trace())
449 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
450 }
451 EXPORT_SYMBOL_GPL(stop_critical_timings);
452 
453 #ifdef CONFIG_IRQSOFF_TRACER
454 #ifdef CONFIG_PROVE_LOCKING
455 void time_hardirqs_on(unsigned long a0, unsigned long a1)
456 {
457 	if (!preempt_trace() && irq_trace())
458 		stop_critical_timing(a0, a1);
459 }
460 
461 void time_hardirqs_off(unsigned long a0, unsigned long a1)
462 {
463 	if (!preempt_trace() && irq_trace())
464 		start_critical_timing(a0, a1);
465 }
466 
467 #else /* !CONFIG_PROVE_LOCKING */
468 
469 /*
470  * We are only interested in hardirq on/off events:
471  */
472 static inline void tracer_hardirqs_on(void)
473 {
474 	if (!preempt_trace() && irq_trace())
475 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
476 }
477 
478 static inline void tracer_hardirqs_off(void)
479 {
480 	if (!preempt_trace() && irq_trace())
481 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
482 }
483 
484 static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
485 {
486 	if (!preempt_trace() && irq_trace())
487 		stop_critical_timing(CALLER_ADDR0, caller_addr);
488 }
489 
490 static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
491 {
492 	if (!preempt_trace() && irq_trace())
493 		start_critical_timing(CALLER_ADDR0, caller_addr);
494 }
495 
496 #endif /* CONFIG_PROVE_LOCKING */
497 #endif /*  CONFIG_IRQSOFF_TRACER */
498 
499 #ifdef CONFIG_PREEMPT_TRACER
500 static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
501 {
502 	if (preempt_trace() && !irq_trace())
503 		stop_critical_timing(a0, a1);
504 }
505 
506 static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
507 {
508 	if (preempt_trace() && !irq_trace())
509 		start_critical_timing(a0, a1);
510 }
511 #endif /* CONFIG_PREEMPT_TRACER */
512 
513 #ifdef CONFIG_FUNCTION_TRACER
514 static bool function_enabled;
515 
516 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
517 {
518 	int ret;
519 
520 	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
521 	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
522 		return 0;
523 
524 	if (graph)
525 		ret = register_ftrace_graph(&irqsoff_graph_return,
526 					    &irqsoff_graph_entry);
527 	else
528 		ret = register_ftrace_function(tr->ops);
529 
530 	if (!ret)
531 		function_enabled = true;
532 
533 	return ret;
534 }
535 
536 static void unregister_irqsoff_function(struct trace_array *tr, int graph)
537 {
538 	if (!function_enabled)
539 		return;
540 
541 	if (graph)
542 		unregister_ftrace_graph();
543 	else
544 		unregister_ftrace_function(tr->ops);
545 
546 	function_enabled = false;
547 }
548 
549 static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
550 {
551 	if (!(mask & TRACE_ITER_FUNCTION))
552 		return 0;
553 
554 	if (set)
555 		register_irqsoff_function(tr, is_graph(tr), 1);
556 	else
557 		unregister_irqsoff_function(tr, is_graph(tr));
558 	return 1;
559 }
560 #else
561 static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
562 {
563 	return 0;
564 }
565 static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
566 static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
567 {
568 	return 0;
569 }
570 #endif /* CONFIG_FUNCTION_TRACER */
571 
572 static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
573 {
574 	struct tracer *tracer = tr->current_trace;
575 
576 	if (irqsoff_function_set(tr, mask, set))
577 		return 0;
578 
579 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
580 	if (mask & TRACE_ITER_DISPLAY_GRAPH)
581 		return irqsoff_display_graph(tr, set);
582 #endif
583 
584 	return trace_keep_overwrite(tracer, mask, set);
585 }
586 
587 static int start_irqsoff_tracer(struct trace_array *tr, int graph)
588 {
589 	int ret;
590 
591 	ret = register_irqsoff_function(tr, graph, 0);
592 
593 	if (!ret && tracing_is_enabled())
594 		tracer_enabled = 1;
595 	else
596 		tracer_enabled = 0;
597 
598 	return ret;
599 }
600 
601 static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
602 {
603 	tracer_enabled = 0;
604 
605 	unregister_irqsoff_function(tr, graph);
606 }
607 
608 static bool irqsoff_busy;
609 
610 static int __irqsoff_tracer_init(struct trace_array *tr)
611 {
612 	if (irqsoff_busy)
613 		return -EBUSY;
614 
615 	save_flags = tr->trace_flags;
616 
617 	/* non overwrite screws up the latency tracers */
618 	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
619 	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
620 
621 	tr->max_latency = 0;
622 	irqsoff_trace = tr;
623 	/* make sure that the tracer is visible */
624 	smp_wmb();
625 
626 	ftrace_init_array_ops(tr, irqsoff_tracer_call);
627 
628 	/* Only toplevel instance supports graph tracing */
629 	if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
630 				      is_graph(tr))))
631 		printk(KERN_ERR "failed to start irqsoff tracer\n");
632 
633 	irqsoff_busy = true;
634 	return 0;
635 }
636 
637 static void irqsoff_tracer_reset(struct trace_array *tr)
638 {
639 	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
640 	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
641 
642 	stop_irqsoff_tracer(tr, is_graph(tr));
643 
644 	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
645 	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
646 	ftrace_reset_array_ops(tr);
647 
648 	irqsoff_busy = false;
649 }
650 
651 static void irqsoff_tracer_start(struct trace_array *tr)
652 {
653 	tracer_enabled = 1;
654 }
655 
656 static void irqsoff_tracer_stop(struct trace_array *tr)
657 {
658 	tracer_enabled = 0;
659 }
660 
661 #ifdef CONFIG_IRQSOFF_TRACER
662 static int irqsoff_tracer_init(struct trace_array *tr)
663 {
664 	trace_type = TRACER_IRQS_OFF;
665 
666 	return __irqsoff_tracer_init(tr);
667 }
668 static struct tracer irqsoff_tracer __read_mostly =
669 {
670 	.name		= "irqsoff",
671 	.init		= irqsoff_tracer_init,
672 	.reset		= irqsoff_tracer_reset,
673 	.start		= irqsoff_tracer_start,
674 	.stop		= irqsoff_tracer_stop,
675 	.print_max	= true,
676 	.print_header   = irqsoff_print_header,
677 	.print_line     = irqsoff_print_line,
678 	.flag_changed	= irqsoff_flag_changed,
679 #ifdef CONFIG_FTRACE_SELFTEST
680 	.selftest    = trace_selftest_startup_irqsoff,
681 #endif
682 	.open           = irqsoff_trace_open,
683 	.close          = irqsoff_trace_close,
684 	.allow_instances = true,
685 	.use_max_tr	= true,
686 };
687 # define register_irqsoff(trace) register_tracer(&trace)
688 #else
689 # define register_irqsoff(trace) do { } while (0)
690 #endif
691 
692 #ifdef CONFIG_PREEMPT_TRACER
693 static int preemptoff_tracer_init(struct trace_array *tr)
694 {
695 	trace_type = TRACER_PREEMPT_OFF;
696 
697 	return __irqsoff_tracer_init(tr);
698 }
699 
700 static struct tracer preemptoff_tracer __read_mostly =
701 {
702 	.name		= "preemptoff",
703 	.init		= preemptoff_tracer_init,
704 	.reset		= irqsoff_tracer_reset,
705 	.start		= irqsoff_tracer_start,
706 	.stop		= irqsoff_tracer_stop,
707 	.print_max	= true,
708 	.print_header   = irqsoff_print_header,
709 	.print_line     = irqsoff_print_line,
710 	.flag_changed	= irqsoff_flag_changed,
711 #ifdef CONFIG_FTRACE_SELFTEST
712 	.selftest    = trace_selftest_startup_preemptoff,
713 #endif
714 	.open		= irqsoff_trace_open,
715 	.close		= irqsoff_trace_close,
716 	.allow_instances = true,
717 	.use_max_tr	= true,
718 };
719 # define register_preemptoff(trace) register_tracer(&trace)
720 #else
721 # define register_preemptoff(trace) do { } while (0)
722 #endif
723 
724 #if defined(CONFIG_IRQSOFF_TRACER) && \
725 	defined(CONFIG_PREEMPT_TRACER)
726 
727 static int preemptirqsoff_tracer_init(struct trace_array *tr)
728 {
729 	trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
730 
731 	return __irqsoff_tracer_init(tr);
732 }
733 
734 static struct tracer preemptirqsoff_tracer __read_mostly =
735 {
736 	.name		= "preemptirqsoff",
737 	.init		= preemptirqsoff_tracer_init,
738 	.reset		= irqsoff_tracer_reset,
739 	.start		= irqsoff_tracer_start,
740 	.stop		= irqsoff_tracer_stop,
741 	.print_max	= true,
742 	.print_header   = irqsoff_print_header,
743 	.print_line     = irqsoff_print_line,
744 	.flag_changed	= irqsoff_flag_changed,
745 #ifdef CONFIG_FTRACE_SELFTEST
746 	.selftest    = trace_selftest_startup_preemptirqsoff,
747 #endif
748 	.open		= irqsoff_trace_open,
749 	.close		= irqsoff_trace_close,
750 	.allow_instances = true,
751 	.use_max_tr	= true,
752 };
753 
754 # define register_preemptirqsoff(trace) register_tracer(&trace)
755 #else
756 # define register_preemptirqsoff(trace) do { } while (0)
757 #endif
758 
759 __init static int init_irqsoff_tracer(void)
760 {
761 	register_irqsoff(irqsoff_tracer);
762 	register_preemptoff(preemptoff_tracer);
763 	register_preemptirqsoff(preemptirqsoff_tracer);
764 
765 	return 0;
766 }
767 core_initcall(init_irqsoff_tracer);
768 #endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
769 
770 #ifndef CONFIG_IRQSOFF_TRACER
771 static inline void tracer_hardirqs_on(void) { }
772 static inline void tracer_hardirqs_off(void) { }
773 static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
774 static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
775 #endif
776 
777 #ifndef CONFIG_PREEMPT_TRACER
778 static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
779 static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
780 #endif
781 
782 #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
783 /* Per-cpu variable to prevent redundant calls when IRQs already off */
784 static DEFINE_PER_CPU(int, tracing_irq_cpu);
785 
786 void trace_hardirqs_on(void)
787 {
788 	if (!this_cpu_read(tracing_irq_cpu))
789 		return;
790 
791 	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
792 	tracer_hardirqs_on();
793 
794 	this_cpu_write(tracing_irq_cpu, 0);
795 }
796 EXPORT_SYMBOL(trace_hardirqs_on);
797 
798 void trace_hardirqs_off(void)
799 {
800 	if (this_cpu_read(tracing_irq_cpu))
801 		return;
802 
803 	this_cpu_write(tracing_irq_cpu, 1);
804 
805 	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
806 	tracer_hardirqs_off();
807 }
808 EXPORT_SYMBOL(trace_hardirqs_off);
809 
810 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
811 {
812 	if (!this_cpu_read(tracing_irq_cpu))
813 		return;
814 
815 	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
816 	tracer_hardirqs_on_caller(caller_addr);
817 
818 	this_cpu_write(tracing_irq_cpu, 0);
819 }
820 EXPORT_SYMBOL(trace_hardirqs_on_caller);
821 
822 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
823 {
824 	if (this_cpu_read(tracing_irq_cpu))
825 		return;
826 
827 	this_cpu_write(tracing_irq_cpu, 1);
828 
829 	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
830 	tracer_hardirqs_off_caller(caller_addr);
831 }
832 EXPORT_SYMBOL(trace_hardirqs_off_caller);
833 
834 /*
835  * Stubs:
836  */
837 
838 void trace_softirqs_on(unsigned long ip)
839 {
840 }
841 
842 void trace_softirqs_off(unsigned long ip)
843 {
844 }
845 
846 inline void print_irqtrace_events(struct task_struct *curr)
847 {
848 }
849 #endif
850 
851 #if defined(CONFIG_PREEMPT_TRACER) || \
852 	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
853 void trace_preempt_on(unsigned long a0, unsigned long a1)
854 {
855 	trace_preempt_enable_rcuidle(a0, a1);
856 	tracer_preempt_on(a0, a1);
857 }
858 
859 void trace_preempt_off(unsigned long a0, unsigned long a1)
860 {
861 	trace_preempt_disable_rcuidle(a0, a1);
862 	tracer_preempt_off(a0, a1);
863 }
864 #endif
865