Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
// SPDX-License-Identifier: GPL-2.0
/*
 * ring buffer based function tracer
 *
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
 *
 * Based on code from the latency_tracer, that is:
 *
 *  Copyright (C) 2004-2006 Ingo Molnar
 *  Copyright (C) 2004 Nadia Yvette Chambers
 */
#include <linux/ring_buffer.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/slab.h>
#include <linux/fs.h>

#include "trace.h"

static void tracing_start_function_trace(struct trace_array *tr);
static void tracing_stop_function_trace(struct trace_array *tr);
static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
		    struct ftrace_ops *op, struct ftrace_regs *fregs);
static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
			  struct ftrace_ops *op, struct ftrace_regs *fregs);
static void
function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
			       struct ftrace_ops *op, struct ftrace_regs *fregs);
static void
function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
				     struct ftrace_ops *op,
				     struct ftrace_regs *fregs);
static struct tracer_flags func_flags;

/* Our option */
enum {

	TRACE_FUNC_NO_OPTS		= 0x0, /* No flags set. */
	TRACE_FUNC_OPT_STACK		= 0x1,
	TRACE_FUNC_OPT_NO_REPEATS	= 0x2,

	/* Update this to next highest bit. */
	TRACE_FUNC_OPT_HIGHEST_BIT	= 0x4
};

#define TRACE_FUNC_OPT_MASK	(TRACE_FUNC_OPT_HIGHEST_BIT - 1)

int ftrace_allocate_ftrace_ops(struct trace_array *tr)
{
	struct ftrace_ops *ops;

	/* The top level array uses the "global_ops" */
	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
		return 0;

	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
	if (!ops)
		return -ENOMEM;

	/* Currently only the non stack version is supported */
	ops->func = function_trace_call;
	ops->flags = FTRACE_OPS_FL_PID;

	tr->ops = ops;
	ops->private = tr;

	return 0;
}

void ftrace_free_ftrace_ops(struct trace_array *tr)
{
	kfree(tr->ops);
	tr->ops = NULL;
}

int ftrace_create_function_files(struct trace_array *tr,
				 struct dentry *parent)
{
	/*
	 * The top level array uses the "global_ops", and the files are
	 * created on boot up.
	 */
	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
		return 0;

	if (!tr->ops)
		return -EINVAL;

	ftrace_create_filter_files(tr->ops, parent);

	return 0;
}

void ftrace_destroy_function_files(struct trace_array *tr)
{
	ftrace_destroy_filter_files(tr->ops);
	ftrace_free_ftrace_ops(tr);
}

static ftrace_func_t select_trace_function(u32 flags_val)
{
	switch (flags_val & TRACE_FUNC_OPT_MASK) {
	case TRACE_FUNC_NO_OPTS:
		return function_trace_call;
	case TRACE_FUNC_OPT_STACK:
		return function_stack_trace_call;
	case TRACE_FUNC_OPT_NO_REPEATS:
		return function_no_repeats_trace_call;
	case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS:
		return function_stack_no_repeats_trace_call;
	default:
		return NULL;
	}
}

static bool handle_func_repeats(struct trace_array *tr, u32 flags_val)
{
	if (!tr->last_func_repeats &&
	    (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) {
		tr->last_func_repeats = alloc_percpu(struct trace_func_repeats);
		if (!tr->last_func_repeats)
			return false;
	}

	return true;
}

static int function_trace_init(struct trace_array *tr)
{
	ftrace_func_t func;
	/*
	 * Instance trace_arrays get their ops allocated
	 * at instance creation. Unless it failed
	 * the allocation.
	 */
	if (!tr->ops)
		return -ENOMEM;

	func = select_trace_function(func_flags.val);
	if (!func)
		return -EINVAL;

	if (!handle_func_repeats(tr, func_flags.val))
		return -ENOMEM;

	ftrace_init_array_ops(tr, func);

	tr->array_buffer.cpu = raw_smp_processor_id();

	tracing_start_cmdline_record();
	tracing_start_function_trace(tr);
	return 0;
}

static void function_trace_reset(struct trace_array *tr)
{
	tracing_stop_function_trace(tr);
	tracing_stop_cmdline_record();
	ftrace_reset_array_ops(tr);
}

static void function_trace_start(struct trace_array *tr)
{
	tracing_reset_online_cpus(&tr->array_buffer);
}

static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
		    struct ftrace_ops *op, struct ftrace_regs *fregs)
{
	struct trace_array *tr = op->private;
	struct trace_array_cpu *data;
	unsigned int trace_ctx;
	int bit;
	int cpu;

	if (unlikely(!tr->function_enabled))
		return;

	bit = ftrace_test_recursion_trylock(ip, parent_ip);
	if (bit < 0)
		return;

	trace_ctx = tracing_gen_ctx();

	cpu = smp_processor_id();
	data = per_cpu_ptr(tr->array_buffer.data, cpu);
	if (!atomic_read(&data->disabled))
		trace_function(tr, ip, parent_ip, trace_ctx);

	ftrace_test_recursion_unlock(bit);
}

#ifdef CONFIG_UNWINDER_ORC
/*
 * Skip 2:
 *
 *   function_stack_trace_call()
 *   ftrace_call()
 */
#define STACK_SKIP 2
#else
/*
 * Skip 3:
 *   __trace_stack()
 *   function_stack_trace_call()
 *   ftrace_call()
 */
#define STACK_SKIP 3
#endif

static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
			  struct ftrace_ops *op, struct ftrace_regs *fregs)
{
	struct trace_array *tr = op->private;
	struct trace_array_cpu *data;
	unsigned long flags;
	long disabled;
	int cpu;
	unsigned int trace_ctx;

	if (unlikely(!tr->function_enabled))
		return;

	/*
	 * Need to use raw, since this must be called before the
	 * recursive protection is performed.
	 */
	local_irq_save(flags);
	cpu = raw_smp_processor_id();
	data = per_cpu_ptr(tr->array_buffer.data, cpu);
	disabled = atomic_inc_return(&data->disabled);

	if (likely(disabled == 1)) {
		trace_ctx = tracing_gen_ctx_flags(flags);
		trace_function(tr, ip, parent_ip, trace_ctx);
		__trace_stack(tr, trace_ctx, STACK_SKIP);
	}

	atomic_dec(&data->disabled);
	local_irq_restore(flags);
}

static inline bool is_repeat_check(struct trace_array *tr,
				   struct trace_func_repeats *last_info,
				   unsigned long ip, unsigned long parent_ip)
{
	if (last_info->ip == ip &&
	    last_info->parent_ip == parent_ip &&
	    last_info->count < U16_MAX) {
		last_info->ts_last_call =
			ring_buffer_time_stamp(tr->array_buffer.buffer);
		last_info->count++;
		return true;
	}

	return false;
}

static inline void process_repeats(struct trace_array *tr,
				   unsigned long ip, unsigned long parent_ip,
				   struct trace_func_repeats *last_info,
				   unsigned int trace_ctx)
{
	if (last_info->count) {
		trace_last_func_repeats(tr, last_info, trace_ctx);
		last_info->count = 0;
	}

	last_info->ip = ip;
	last_info->parent_ip = parent_ip;
}

static void
function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
			       struct ftrace_ops *op,
			       struct ftrace_regs *fregs)
{
	struct trace_func_repeats *last_info;
	struct trace_array *tr = op->private;
	struct trace_array_cpu *data;
	unsigned int trace_ctx;
	unsigned long flags;
	int bit;
	int cpu;

	if (unlikely(!tr->function_enabled))
		return;

	bit = ftrace_test_recursion_trylock(ip, parent_ip);
	if (bit < 0)
		return;

	cpu = smp_processor_id();
	data = per_cpu_ptr(tr->array_buffer.data, cpu);
	if (atomic_read(&data->disabled))
		goto out;

	/*
	 * An interrupt may happen at any place here. But as far as I can see,
	 * the only damage that this can cause is to mess up the repetition
	 * counter without valuable data being lost.
	 * TODO: think about a solution that is better than just hoping to be
	 * lucky.
	 */
	last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
	if (is_repeat_check(tr, last_info, ip, parent_ip))
		goto out;

	local_save_flags(flags);
	trace_ctx = tracing_gen_ctx_flags(flags);
	process_repeats(tr, ip, parent_ip, last_info, trace_ctx);

	trace_function(tr, ip, parent_ip, trace_ctx);

out:
	ftrace_test_recursion_unlock(bit);
}

static void
function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
				     struct ftrace_ops *op,
				     struct ftrace_regs *fregs)
{
	struct trace_func_repeats *last_info;
	struct trace_array *tr = op->private;
	struct trace_array_cpu *data;
	unsigned long flags;
	long disabled;
	int cpu;
	unsigned int trace_ctx;

	if (unlikely(!tr->function_enabled))
		return;

	/*
	 * Need to use raw, since this must be called before the
	 * recursive protection is performed.
	 */
	local_irq_save(flags);
	cpu = raw_smp_processor_id();
	data = per_cpu_ptr(tr->array_buffer.data, cpu);
	disabled = atomic_inc_return(&data->disabled);

	if (likely(disabled == 1)) {
		last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
		if (is_repeat_check(tr, last_info, ip, parent_ip))
			goto out;

		trace_ctx = tracing_gen_ctx_flags(flags);
		process_repeats(tr, ip, parent_ip, last_info, trace_ctx);

		trace_function(tr, ip, parent_ip, trace_ctx);
		__trace_stack(tr, trace_ctx, STACK_SKIP);
	}

 out:
	atomic_dec(&data->disabled);
	local_irq_restore(flags);
}

static struct tracer_opt func_opts[] = {
#ifdef CONFIG_STACKTRACE
	{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
#endif
	{ TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
	{ } /* Always set a last empty entry */
};

static struct tracer_flags func_flags = {
	.val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */
	.opts = func_opts
};

static void tracing_start_function_trace(struct trace_array *tr)
{
	tr->function_enabled = 0;
	register_ftrace_function(tr->ops);
	tr->function_enabled = 1;
}

static void tracing_stop_function_trace(struct trace_array *tr)
{
	tr->function_enabled = 0;
	unregister_ftrace_function(tr->ops);
}

static struct tracer function_trace;

static int
func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
{
	ftrace_func_t func;
	u32 new_flags;

	/* Do nothing if already set. */
	if (!!set == !!(func_flags.val & bit))
		return 0;

	/* We can change this flag only when not running. */
	if (tr->current_trace != &function_trace)
		return 0;

	new_flags = (func_flags.val & ~bit) | (set ? bit : 0);
	func = select_trace_function(new_flags);
	if (!func)
		return -EINVAL;

	/* Check if there's anything to change. */
	if (tr->ops->func == func)
		return 0;

	if (!handle_func_repeats(tr, new_flags))
		return -ENOMEM;

	unregister_ftrace_function(tr->ops);
	tr->ops->func = func;
	register_ftrace_function(tr->ops);

	return 0;
}

static struct tracer function_trace __tracer_data =
{
	.name		= "function",
	.init		= function_trace_init,
	.reset		= function_trace_reset,
	.start		= function_trace_start,
	.flags		= &func_flags,
	.set_flag	= func_set_flag,
	.allow_instances = true,
#ifdef CONFIG_FTRACE_SELFTEST
	.selftest	= trace_selftest_startup_function,
#endif
};

#ifdef CONFIG_DYNAMIC_FTRACE
static void update_traceon_count(struct ftrace_probe_ops *ops,
				 unsigned long ip,
				 struct trace_array *tr, bool on,
				 void *data)
{
	struct ftrace_func_mapper *mapper = data;
	long *count;
	long old_count;

	/*
	 * Tracing gets disabled (or enabled) once per count.
	 * This function can be called at the same time on multiple CPUs.
	 * It is fine if both disable (or enable) tracing, as disabling
	 * (or enabling) the second time doesn't do anything as the
	 * state of the tracer is already disabled (or enabled).
	 * What needs to be synchronized in this case is that the count
	 * only gets decremented once, even if the tracer is disabled
	 * (or enabled) twice, as the second one is really a nop.
	 *
	 * The memory barriers guarantee that we only decrement the
	 * counter once. First the count is read to a local variable
	 * and a read barrier is used to make sure that it is loaded
	 * before checking if the tracer is in the state we want.
	 * If the tracer is not in the state we want, then the count
	 * is guaranteed to be the old count.
	 *
	 * Next the tracer is set to the state we want (disabled or enabled)
	 * then a write memory barrier is used to make sure that
	 * the new state is visible before changing the counter by
	 * one minus the old counter. This guarantees that another CPU
	 * executing this code will see the new state before seeing
	 * the new counter value, and would not do anything if the new
	 * counter is seen.
	 *
	 * Note, there is no synchronization between this and a user
	 * setting the tracing_on file. But we currently don't care
	 * about that.
	 */
	count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
	old_count = *count;

	if (old_count <= 0)
		return;

	/* Make sure we see count before checking tracing state */
	smp_rmb();

	if (on == !!tracer_tracing_is_on(tr))
		return;

	if (on)
		tracer_tracing_on(tr);
	else
		tracer_tracing_off(tr);

	/* Make sure tracing state is visible before updating count */
	smp_wmb();

	*count = old_count - 1;
}

static void
ftrace_traceon_count(unsigned long ip, unsigned long parent_ip,
		     struct trace_array *tr, struct ftrace_probe_ops *ops,
		     void *data)
{
	update_traceon_count(ops, ip, tr, 1, data);
}

static void
ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip,
		      struct trace_array *tr, struct ftrace_probe_ops *ops,
		      void *data)
{
	update_traceon_count(ops, ip, tr, 0, data);
}

static void
ftrace_traceon(unsigned long ip, unsigned long parent_ip,
	       struct trace_array *tr, struct ftrace_probe_ops *ops,
	       void *data)
{
	if (tracer_tracing_is_on(tr))
		return;

	tracer_tracing_on(tr);
}

static void
ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
		struct trace_array *tr, struct ftrace_probe_ops *ops,
		void *data)
{
	if (!tracer_tracing_is_on(tr))
		return;

	tracer_tracing_off(tr);
}

#ifdef CONFIG_UNWINDER_ORC
/*
 * Skip 3:
 *
 *   function_trace_probe_call()
 *   ftrace_ops_assist_func()
 *   ftrace_call()
 */
#define FTRACE_STACK_SKIP 3
#else
/*
 * Skip 5:
 *
 *   __trace_stack()
 *   ftrace_stacktrace()
 *   function_trace_probe_call()
 *   ftrace_ops_assist_func()
 *   ftrace_call()
 */
#define FTRACE_STACK_SKIP 5
#endif

static __always_inline void trace_stack(struct trace_array *tr)
{
	unsigned int trace_ctx;

	trace_ctx = tracing_gen_ctx();

	__trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP);
}

static void
ftrace_stacktrace(unsigned long ip, unsigned long parent_ip,
		  struct trace_array *tr, struct ftrace_probe_ops *ops,
		  void *data)
{
	trace_stack(tr);
}

static void
ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip,
			struct trace_array *tr, struct ftrace_probe_ops *ops,
			void *data)
{
	struct ftrace_func_mapper *mapper = data;
	long *count;
	long old_count;
	long new_count;

	if (!tracing_is_on())
		return;

	/* unlimited? */
	if (!mapper) {
		trace_stack(tr);
		return;
	}

	count = (long *)ftrace_func_mapper_find_ip(mapper, ip);

	/*
	 * Stack traces should only execute the number of times the
	 * user specified in the counter.
	 */
	do {
		old_count = *count;

		if (!old_count)
			return;

		new_count = old_count - 1;
		new_count = cmpxchg(count, old_count, new_count);
		if (new_count == old_count)
			trace_stack(tr);

		if (!tracing_is_on())
			return;

	} while (new_count != old_count);
}

static int update_count(struct ftrace_probe_ops *ops, unsigned long ip,
			void *data)
{
	struct ftrace_func_mapper *mapper = data;
	long *count = NULL;

	if (mapper)
		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);

	if (count) {
		if (*count <= 0)
			return 0;
		(*count)--;
	}

	return 1;
}

static void
ftrace_dump_probe(unsigned long ip, unsigned long parent_ip,
		  struct trace_array *tr, struct ftrace_probe_ops *ops,
		  void *data)
{
	if (update_count(ops, ip, data))
		ftrace_dump(DUMP_ALL);
}

/* Only dump the current CPU buffer. */
static void
ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip,
		     struct trace_array *tr, struct ftrace_probe_ops *ops,
		     void *data)
{
	if (update_count(ops, ip, data))
		ftrace_dump(DUMP_ORIG);
}

static int
ftrace_probe_print(const char *name, struct seq_file *m,
		   unsigned long ip, struct ftrace_probe_ops *ops,
		   void *data)
{
	struct ftrace_func_mapper *mapper = data;
	long *count = NULL;

	seq_printf(m, "%ps:%s", (void *)ip, name);

	if (mapper)
		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);

	if (count)
		seq_printf(m, ":count=%ld\n", *count);
	else
		seq_puts(m, ":unlimited\n");

	return 0;
}

static int
ftrace_traceon_print(struct seq_file *m, unsigned long ip,
		     struct ftrace_probe_ops *ops,
		     void *data)
{
	return ftrace_probe_print("traceon", m, ip, ops, data);
}

static int
ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
			 struct ftrace_probe_ops *ops, void *data)
{
	return ftrace_probe_print("traceoff", m, ip, ops, data);
}

static int
ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
			struct ftrace_probe_ops *ops, void *data)
{
	return ftrace_probe_print("stacktrace", m, ip, ops, data);
}

static int
ftrace_dump_print(struct seq_file *m, unsigned long ip,
			struct ftrace_probe_ops *ops, void *data)
{
	return ftrace_probe_print("dump", m, ip, ops, data);
}

static int
ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
			struct ftrace_probe_ops *ops, void *data)
{
	return ftrace_probe_print("cpudump", m, ip, ops, data);
}


static int
ftrace_count_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
		  unsigned long ip, void *init_data, void **data)
{
	struct ftrace_func_mapper *mapper = *data;

	if (!mapper) {
		mapper = allocate_ftrace_func_mapper();
		if (!mapper)
			return -ENOMEM;
		*data = mapper;
	}

	return ftrace_func_mapper_add_ip(mapper, ip, init_data);
}

static void
ftrace_count_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
		  unsigned long ip, void *data)
{
	struct ftrace_func_mapper *mapper = data;

	if (!ip) {
		free_ftrace_func_mapper(mapper, NULL);
		return;
	}

	ftrace_func_mapper_remove_ip(mapper, ip);
}

static struct ftrace_probe_ops traceon_count_probe_ops = {
	.func			= ftrace_traceon_count,
	.print			= ftrace_traceon_print,
	.init			= ftrace_count_init,
	.free			= ftrace_count_free,
};

static struct ftrace_probe_ops traceoff_count_probe_ops = {
	.func			= ftrace_traceoff_count,
	.print			= ftrace_traceoff_print,
	.init			= ftrace_count_init,
	.free			= ftrace_count_free,
};

static struct ftrace_probe_ops stacktrace_count_probe_ops = {
	.func			= ftrace_stacktrace_count,
	.print			= ftrace_stacktrace_print,
	.init			= ftrace_count_init,
	.free			= ftrace_count_free,
};

static struct ftrace_probe_ops dump_probe_ops = {
	.func			= ftrace_dump_probe,
	.print			= ftrace_dump_print,
	.init			= ftrace_count_init,
	.free			= ftrace_count_free,
};

static struct ftrace_probe_ops cpudump_probe_ops = {
	.func			= ftrace_cpudump_probe,
	.print			= ftrace_cpudump_print,
};

static struct ftrace_probe_ops traceon_probe_ops = {
	.func			= ftrace_traceon,
	.print			= ftrace_traceon_print,
};

static struct ftrace_probe_ops traceoff_probe_ops = {
	.func			= ftrace_traceoff,
	.print			= ftrace_traceoff_print,
};

static struct ftrace_probe_ops stacktrace_probe_ops = {
	.func			= ftrace_stacktrace,
	.print			= ftrace_stacktrace_print,
};

static int
ftrace_trace_probe_callback(struct trace_array *tr,
			    struct ftrace_probe_ops *ops,
			    struct ftrace_hash *hash, char *glob,
			    char *cmd, char *param, int enable)
{
	void *count = (void *)-1;
	char *number;
	int ret;

	/* hash funcs only work with set_ftrace_filter */
	if (!enable)
		return -EINVAL;

	if (glob[0] == '!')
		return unregister_ftrace_function_probe_func(glob+1, tr, ops);

	if (!param)
		goto out_reg;

	number = strsep(&param, ":");

	if (!strlen(number))
		goto out_reg;

	/*
	 * We use the callback data field (which is a pointer)
	 * as our counter.
	 */
	ret = kstrtoul(number, 0, (unsigned long *)&count);
	if (ret)
		return ret;

 out_reg:
	ret = register_ftrace_function_probe(glob, tr, ops, count);

	return ret < 0 ? ret : 0;
}

static int
ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash,
			    char *glob, char *cmd, char *param, int enable)
{
	struct ftrace_probe_ops *ops;

	if (!tr)
		return -ENODEV;

	/* we register both traceon and traceoff to this callback */
	if (strcmp(cmd, "traceon") == 0)
		ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
	else
		ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;

	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
					   param, enable);
}

static int
ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash,
			   char *glob, char *cmd, char *param, int enable)
{
	struct ftrace_probe_ops *ops;

	if (!tr)
		return -ENODEV;

	ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;

	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
					   param, enable);
}

static int
ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash,
			   char *glob, char *cmd, char *param, int enable)
{
	struct ftrace_probe_ops *ops;

	if (!tr)
		return -ENODEV;

	ops = &dump_probe_ops;

	/* Only dump once. */
	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
					   "1", enable);
}

static int
ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash,
			   char *glob, char *cmd, char *param, int enable)
{
	struct ftrace_probe_ops *ops;

	if (!tr)
		return -ENODEV;

	ops = &cpudump_probe_ops;

	/* Only dump once. */
	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
					   "1", enable);
}

static struct ftrace_func_command ftrace_traceon_cmd = {
	.name			= "traceon",
	.func			= ftrace_trace_onoff_callback,
};

static struct ftrace_func_command ftrace_traceoff_cmd = {
	.name			= "traceoff",
	.func			= ftrace_trace_onoff_callback,
};

static struct ftrace_func_command ftrace_stacktrace_cmd = {
	.name			= "stacktrace",
	.func			= ftrace_stacktrace_callback,
};

static struct ftrace_func_command ftrace_dump_cmd = {
	.name			= "dump",
	.func			= ftrace_dump_callback,
};

static struct ftrace_func_command ftrace_cpudump_cmd = {
	.name			= "cpudump",
	.func			= ftrace_cpudump_callback,
};

static int __init init_func_cmd_traceon(void)
{
	int ret;

	ret = register_ftrace_command(&ftrace_traceoff_cmd);
	if (ret)
		return ret;

	ret = register_ftrace_command(&ftrace_traceon_cmd);
	if (ret)
		goto out_free_traceoff;

	ret = register_ftrace_command(&ftrace_stacktrace_cmd);
	if (ret)
		goto out_free_traceon;

	ret = register_ftrace_command(&ftrace_dump_cmd);
	if (ret)
		goto out_free_stacktrace;

	ret = register_ftrace_command(&ftrace_cpudump_cmd);
	if (ret)
		goto out_free_dump;

	return 0;

 out_free_dump:
	unregister_ftrace_command(&ftrace_dump_cmd);
 out_free_stacktrace:
	unregister_ftrace_command(&ftrace_stacktrace_cmd);
 out_free_traceon:
	unregister_ftrace_command(&ftrace_traceon_cmd);
 out_free_traceoff:
	unregister_ftrace_command(&ftrace_traceoff_cmd);

	return ret;
}
#else
static inline int init_func_cmd_traceon(void)
{
	return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */

__init int init_function_trace(void)
{
	init_func_cmd_traceon();
	return register_tracer(&function_trace);
}