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)
 23static struct trace_array		*irqsoff_trace __read_mostly;
 24static int				tracer_enabled __read_mostly;
 25
 26static DEFINE_PER_CPU(int, tracing_cpu);
 27
 28static DEFINE_RAW_SPINLOCK(max_trace_lock);
 29
 30enum {
 31	TRACER_IRQS_OFF		= (1 << 1),
 32	TRACER_PREEMPT_OFF	= (1 << 2),
 33};
 34
 35static int trace_type __read_mostly;
 36
 37static int save_flags;
 38
 39static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
 40static int start_irqsoff_tracer(struct trace_array *tr, int graph);
 41
 42#ifdef CONFIG_PREEMPT_TRACER
 43static inline int
 44preempt_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
 53static inline int
 54irq_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
 64static int irqsoff_display_graph(struct trace_array *tr, int set);
 65# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
 66#else
 67static 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 */
 82static __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 */
 98static 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 */
138static void
139irqsoff_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
156static 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
174static 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
204static 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
219static void irqsoff_trace_open(struct trace_iterator *iter)
220{
221	if (is_graph(iter->tr))
222		graph_trace_open(iter);
223
224}
225
226static 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
237static 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
249static 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
259static 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
 
 
 
 
274static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
275{
276	return -1;
277}
278#endif
279
280static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
281{
282	return TRACE_TYPE_UNHANDLED;
283}
284
 
285static void irqsoff_trace_open(struct trace_iterator *iter) { }
286static void irqsoff_trace_close(struct trace_iterator *iter) { }
287
288#ifdef CONFIG_FUNCTION_TRACER
289static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
290static void irqsoff_print_header(struct seq_file *s)
291{
292	trace_default_header(s);
293}
294#else
295static 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 */
305static 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
317static void
318check_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
360out_unlock:
361	raw_spin_unlock_irqrestore(&max_trace_lock, flags);
362
363out:
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
369static inline void
370start_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
405static inline void
406stop_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) */
439void start_critical_timings(void)
440{
441	if (preempt_trace() || irq_trace())
442		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
443}
444EXPORT_SYMBOL_GPL(start_critical_timings);
445
446void stop_critical_timings(void)
447{
448	if (preempt_trace() || irq_trace())
449		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
450}
451EXPORT_SYMBOL_GPL(stop_critical_timings);
452
453#ifdef CONFIG_IRQSOFF_TRACER
454#ifdef CONFIG_PROVE_LOCKING
455void time_hardirqs_on(unsigned long a0, unsigned long a1)
456{
457	if (!preempt_trace() && irq_trace())
458		stop_critical_timing(a0, a1);
459}
460
461void 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 */
472static inline void tracer_hardirqs_on(void)
473{
474	if (!preempt_trace() && irq_trace())
475		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
476}
 
477
478static inline void tracer_hardirqs_off(void)
479{
480	if (!preempt_trace() && irq_trace())
481		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
482}
 
483
484static 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
490static 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
500static 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
506static 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
514static bool function_enabled;
515
516static 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
536static 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
549static 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
561static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
562{
563	return 0;
564}
565static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
566static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
567{
568	return 0;
569}
570#endif /* CONFIG_FUNCTION_TRACER */
571
572static 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
587static 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
601static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
602{
603	tracer_enabled = 0;
604
605	unregister_irqsoff_function(tr, graph);
 
 
 
606}
607
608static bool irqsoff_busy;
609
610static 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
637static 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
651static void irqsoff_tracer_start(struct trace_array *tr)
652{
653	tracer_enabled = 1;
654}
655
656static void irqsoff_tracer_stop(struct trace_array *tr)
657{
658	tracer_enabled = 0;
659}
660
661#ifdef CONFIG_IRQSOFF_TRACER
662static int irqsoff_tracer_init(struct trace_array *tr)
663{
664	trace_type = TRACER_IRQS_OFF;
665
666	return __irqsoff_tracer_init(tr);
 
667}
668static 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
693static int preemptoff_tracer_init(struct trace_array *tr)
694{
695	trace_type = TRACER_PREEMPT_OFF;
696
697	return __irqsoff_tracer_init(tr);
 
698}
699
700static 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
727static 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
734static 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}
767core_initcall(init_irqsoff_tracer);
768#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
769
770#ifndef CONFIG_IRQSOFF_TRACER
771static inline void tracer_hardirqs_on(void) { }
772static inline void tracer_hardirqs_off(void) { }
773static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
774static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
775#endif
776
777#ifndef CONFIG_PREEMPT_TRACER
778static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
779static 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 */
784static DEFINE_PER_CPU(int, tracing_irq_cpu);
785
786void 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}
796EXPORT_SYMBOL(trace_hardirqs_on);
797
798void 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}
808EXPORT_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}
820EXPORT_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}
832EXPORT_SYMBOL(trace_hardirqs_off_caller);
833
834/*
835 * Stubs:
836 */
837
838void trace_softirqs_on(unsigned long ip)
839{
840}
841
842void trace_softirqs_off(unsigned long ip)
843{
844}
845
846inline 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))
853void 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
859void 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