summaryrefslogtreecommitdiff
path: root/include/linux/ftrace.h
blob: dd16e8218db3a7a9cb3988b973ae500f683cd076 (plain)
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
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Ftrace header.  For implementation details beyond the random comments
 * scattered below, see: Documentation/trace/ftrace-design.rst
 */

#ifndef _LINUX_FTRACE_H
#define _LINUX_FTRACE_H

#include <linux/trace_clock.h>
#include <linux/kallsyms.h>
#include <linux/linkage.h>
#include <linux/bitops.h>
#include <linux/ptrace.h>
#include <linux/ktime.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/fs.h>

#include <asm/ftrace.h>

/*
 * If the arch supports passing the variable contents of
 * function_trace_op as the third parameter back from the
 * mcount call, then the arch should define this as 1.
 */
#ifndef ARCH_SUPPORTS_FTRACE_OPS
#define ARCH_SUPPORTS_FTRACE_OPS 0
#endif

/*
 * If the arch's mcount caller does not support all of ftrace's
 * features, then it must call an indirect function that
 * does. Or at least does enough to prevent any unwelcomed side effects.
 */
#if !ARCH_SUPPORTS_FTRACE_OPS
# define FTRACE_FORCE_LIST_FUNC 1
#else
# define FTRACE_FORCE_LIST_FUNC 0
#endif

/* Main tracing buffer and events set up */
#ifdef CONFIG_TRACING
void trace_init(void);
void early_trace_init(void);
#else
static inline void trace_init(void) { }
static inline void early_trace_init(void) { }
#endif

struct module;
struct ftrace_hash;

#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
	defined(CONFIG_DYNAMIC_FTRACE)
const char *
ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
		   unsigned long *off, char **modname, char *sym);
int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
			   char *type, char *name,
			   char *module_name, int *exported);
#else
static inline const char *
ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
		   unsigned long *off, char **modname, char *sym)
{
	return NULL;
}
static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
					 char *type, char *name,
					 char *module_name, int *exported)
{
	return -1;
}
#endif


#ifdef CONFIG_FUNCTION_TRACER

extern int ftrace_enabled;
extern int
ftrace_enable_sysctl(struct ctl_table *table, int write,
		     void __user *buffer, size_t *lenp,
		     loff_t *ppos);

struct ftrace_ops;

typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
			      struct ftrace_ops *op, struct pt_regs *regs);

ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);

/*
 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
 * set in the flags member.
 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
 * IPMODIFY are a kind of attribute flags which can be set only before
 * registering the ftrace_ops, and can not be modified while registered.
 * Changing those attribute flags after registering ftrace_ops will
 * cause unexpected results.
 *
 * ENABLED - set/unset when ftrace_ops is registered/unregistered
 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
 *           allocated ftrace_ops which need special care
 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
 *            and passed to the callback. If this flag is set, but the
 *            architecture does not support passing regs
 *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
 *            ftrace_ops will fail to register, unless the next flag
 *            is set.
 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
 *            handler can handle an arch that does not save regs
 *            (the handler tests if regs == NULL), then it can set
 *            this flag instead. It will not fail registering the ftrace_ops
 *            but, the regs field will be NULL if the arch does not support
 *            passing regs to the handler.
 *            Note, if this flag is set, the SAVE_REGS flag will automatically
 *            get set upon registering the ftrace_ops, if the arch supports it.
 * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
 *            that the call back has its own recursion protection. If it does
 *            not set this, then the ftrace infrastructure will add recursion
 *            protection for the caller.
 * STUB   - The ftrace_ops is just a place holder.
 * INITIALIZED - The ftrace_ops has already been initialized (first use time
 *            register_ftrace_function() is called, it will initialized the ops)
 * DELETED - The ops are being deleted, do not let them be registered again.
 * ADDING  - The ops is in the process of being added.
 * REMOVING - The ops is in the process of being removed.
 * MODIFYING - The ops is in the process of changing its filter functions.
 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
 *            The arch specific code sets this flag when it allocated a
 *            trampoline. This lets the arch know that it can update the
 *            trampoline in case the callback function changes.
 *            The ftrace_ops trampoline can be set by the ftrace users, and
 *            in such cases the arch must not modify it. Only the arch ftrace
 *            core code should set this flag.
 * IPMODIFY - The ops can modify the IP register. This can only be set with
 *            SAVE_REGS. If another ops with this flag set is already registered
 *            for any of the functions that this ops will be registered for, then
 *            this ops will fail to register or set_filter_ip.
 * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
 * RCU     - Set when the ops can only be called when RCU is watching.
 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
 */
enum {
	FTRACE_OPS_FL_ENABLED			= 1 << 0,
	FTRACE_OPS_FL_DYNAMIC			= 1 << 1,
	FTRACE_OPS_FL_SAVE_REGS			= 1 << 2,
	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 3,
	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 4,
	FTRACE_OPS_FL_STUB			= 1 << 5,
	FTRACE_OPS_FL_INITIALIZED		= 1 << 6,
	FTRACE_OPS_FL_DELETED			= 1 << 7,
	FTRACE_OPS_FL_ADDING			= 1 << 8,
	FTRACE_OPS_FL_REMOVING			= 1 << 9,
	FTRACE_OPS_FL_MODIFYING			= 1 << 10,
	FTRACE_OPS_FL_ALLOC_TRAMP		= 1 << 11,
	FTRACE_OPS_FL_IPMODIFY			= 1 << 12,
	FTRACE_OPS_FL_PID			= 1 << 13,
	FTRACE_OPS_FL_RCU			= 1 << 14,
	FTRACE_OPS_FL_TRACE_ARRAY		= 1 << 15,
};

#ifdef CONFIG_DYNAMIC_FTRACE
/* The hash used to know what functions callbacks trace */
struct ftrace_ops_hash {
	struct ftrace_hash __rcu	*notrace_hash;
	struct ftrace_hash __rcu	*filter_hash;
	struct mutex			regex_lock;
};

void ftrace_free_init_mem(void);
void ftrace_free_mem(struct module *mod, void *start, void *end);
#else
static inline void ftrace_free_init_mem(void) { }
static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
#endif

/*
 * Note, ftrace_ops can be referenced outside of RCU protection, unless
 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
 * core data, the unregistering of it will perform a scheduling on all CPUs
 * to make sure that there are no more users. Depending on the load of the
 * system that may take a bit of time.
 *
 * Any private data added must also take care not to be freed and if private
 * data is added to a ftrace_ops that is in core code, the user of the
 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
 */
struct ftrace_ops {
	ftrace_func_t			func;
	struct ftrace_ops __rcu		*next;
	unsigned long			flags;
	void				*private;
	ftrace_func_t			saved_func;
#ifdef CONFIG_DYNAMIC_FTRACE
	struct ftrace_ops_hash		local_hash;
	struct ftrace_ops_hash		*func_hash;
	struct ftrace_ops_hash		old_hash;
	unsigned long			trampoline;
	unsigned long			trampoline_size;
#endif
};

/*
 * Type of the current tracing.
 */
enum ftrace_tracing_type_t {
	FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
	FTRACE_TYPE_RETURN,	/* Hook the return of the function */
};

/* Current tracing type, default is FTRACE_TYPE_ENTER */
extern enum ftrace_tracing_type_t ftrace_tracing_type;

/*
 * The ftrace_ops must be a static and should also
 * be read_mostly.  These functions do modify read_mostly variables
 * so use them sparely. Never free an ftrace_op or modify the
 * next pointer after it has been registered. Even after unregistering
 * it, the next pointer may still be used internally.
 */
int register_ftrace_function(struct ftrace_ops *ops);
int unregister_ftrace_function(struct ftrace_ops *ops);

extern void ftrace_stub(unsigned long a0, unsigned long a1,
			struct ftrace_ops *op, struct pt_regs *regs);

#else /* !CONFIG_FUNCTION_TRACER */
/*
 * (un)register_ftrace_function must be a macro since the ops parameter
 * must not be evaluated.
 */
#define register_ftrace_function(ops) ({ 0; })
#define unregister_ftrace_function(ops) ({ 0; })
static inline void ftrace_kill(void) { }
static inline void ftrace_free_init_mem(void) { }
static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
#endif /* CONFIG_FUNCTION_TRACER */

#ifdef CONFIG_STACK_TRACER

#define STACK_TRACE_ENTRIES 500

struct stack_trace;

extern unsigned stack_trace_index[];
extern struct stack_trace stack_trace_max;
extern unsigned long stack_trace_max_size;
extern arch_spinlock_t stack_trace_max_lock;

extern int stack_tracer_enabled;
void stack_trace_print(void);
int
stack_trace_sysctl(struct ctl_table *table, int write,
		   void __user *buffer, size_t *lenp,
		   loff_t *ppos);

/* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
DECLARE_PER_CPU(int, disable_stack_tracer);

/**
 * stack_tracer_disable - temporarily disable the stack tracer
 *
 * There's a few locations (namely in RCU) where stack tracing
 * cannot be executed. This function is used to disable stack
 * tracing during those critical sections.
 *
 * This function must be called with preemption or interrupts
 * disabled and stack_tracer_enable() must be called shortly after
 * while preemption or interrupts are still disabled.
 */
static inline void stack_tracer_disable(void)
{
	/* Preemption or interupts must be disabled */
	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
	this_cpu_inc(disable_stack_tracer);
}

/**
 * stack_tracer_enable - re-enable the stack tracer
 *
 * After stack_tracer_disable() is called, stack_tracer_enable()
 * must be called shortly afterward.
 */
static inline void stack_tracer_enable(void)
{
	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
	this_cpu_dec(disable_stack_tracer);
}
#else
static inline void stack_tracer_disable(void) { }
static inline void stack_tracer_enable(void) { }
#endif

#ifdef CONFIG_DYNAMIC_FTRACE

int ftrace_arch_code_modify_prepare(void);
int ftrace_arch_code_modify_post_process(void);

struct dyn_ftrace;

enum ftrace_bug_type {
	FTRACE_BUG_UNKNOWN,
	FTRACE_BUG_INIT,
	FTRACE_BUG_NOP,
	FTRACE_BUG_CALL,
	FTRACE_BUG_UPDATE,
};
extern enum ftrace_bug_type ftrace_bug_type;

/*
 * Archs can set this to point to a variable that holds the value that was
 * expected at the call site before calling ftrace_bug().
 */
extern const void *ftrace_expected;

void ftrace_bug(int err, struct dyn_ftrace *rec);

struct seq_file;

extern int ftrace_text_reserved(const void *start, const void *end);

struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);

bool is_ftrace_trampoline(unsigned long addr);

/*
 * The dyn_ftrace record's flags field is split into two parts.
 * the first part which is '0-FTRACE_REF_MAX' is a counter of
 * the number of callbacks that have registered the function that
 * the dyn_ftrace descriptor represents.
 *
 * The second part is a mask:
 *  ENABLED - the function is being traced
 *  REGS    - the record wants the function to save regs
 *  REGS_EN - the function is set up to save regs.
 *  IPMODIFY - the record allows for the IP address to be changed.
 *  DISABLED - the record is not ready to be touched yet
 *
 * When a new ftrace_ops is registered and wants a function to save
 * pt_regs, the rec->flag REGS is set. When the function has been
 * set up to save regs, the REG_EN flag is set. Once a function
 * starts saving regs it will do so until all ftrace_ops are removed
 * from tracing that function.
 */
enum {
	FTRACE_FL_ENABLED	= (1UL << 31),
	FTRACE_FL_REGS		= (1UL << 30),
	FTRACE_FL_REGS_EN	= (1UL << 29),
	FTRACE_FL_TRAMP		= (1UL << 28),
	FTRACE_FL_TRAMP_EN	= (1UL << 27),
	FTRACE_FL_IPMODIFY	= (1UL << 26),
	FTRACE_FL_DISABLED	= (1UL << 25),
};

#define FTRACE_REF_MAX_SHIFT	25
#define FTRACE_FL_BITS		7
#define FTRACE_FL_MASKED_BITS	((1UL << FTRACE_FL_BITS) - 1)
#define FTRACE_FL_MASK		(FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
#define FTRACE_REF_MAX		((1UL << FTRACE_REF_MAX_SHIFT) - 1)

#define ftrace_rec_count(rec)	((rec)->flags & ~FTRACE_FL_MASK)

struct dyn_ftrace {
	unsigned long		ip; /* address of mcount call-site */
	unsigned long		flags;
	struct dyn_arch_ftrace	arch;
};

int ftrace_force_update(void);
int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
			 int remove, int reset);
int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
		       int len, int reset);
int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
			int len, int reset);
void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
void ftrace_free_filter(struct ftrace_ops *ops);
void ftrace_ops_set_global_filter(struct ftrace_ops *ops);

enum {
	FTRACE_UPDATE_CALLS		= (1 << 0),
	FTRACE_DISABLE_CALLS		= (1 << 1),
	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
	FTRACE_START_FUNC_RET		= (1 << 3),
	FTRACE_STOP_FUNC_RET		= (1 << 4),
};

/*
 * The FTRACE_UPDATE_* enum is used to pass information back
 * from the ftrace_update_record() and ftrace_test_record()
 * functions. These are called by the code update routines
 * to find out what is to be done for a given function.
 *
 *  IGNORE           - The function is already what we want it to be
 *  MAKE_CALL        - Start tracing the function
 *  MODIFY_CALL      - Stop saving regs for the function
 *  MAKE_NOP         - Stop tracing the function
 */
enum {
	FTRACE_UPDATE_IGNORE,
	FTRACE_UPDATE_MAKE_CALL,
	FTRACE_UPDATE_MODIFY_CALL,
	FTRACE_UPDATE_MAKE_NOP,
};

enum {
	FTRACE_ITER_FILTER	= (1 << 0),
	FTRACE_ITER_NOTRACE	= (1 << 1),
	FTRACE_ITER_PRINTALL	= (1 << 2),
	FTRACE_ITER_DO_PROBES	= (1 << 3),
	FTRACE_ITER_PROBE	= (1 << 4),
	FTRACE_ITER_MOD		= (1 << 5),
	FTRACE_ITER_ENABLED	= (1 << 6),
};

void arch_ftrace_update_code(int command);

struct ftrace_rec_iter;

struct ftrace_rec_iter *ftrace_rec_iter_start(void);
struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);

#define for_ftrace_rec_iter(iter)		\
	for (iter = ftrace_rec_iter_start();	\
	     iter;				\
	     iter = ftrace_rec_iter_next(iter))


int ftrace_update_record(struct dyn_ftrace *rec, int enable);
int ftrace_test_record(struct dyn_ftrace *rec, int enable);
void ftrace_run_stop_machine(int command);
unsigned long ftrace_location(unsigned long ip);
unsigned long ftrace_location_range(unsigned long start, unsigned long end);
unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);

extern ftrace_func_t ftrace_trace_function;

int ftrace_regex_open(struct ftrace_ops *ops, int flag,
		  struct inode *inode, struct file *file);
ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
			    size_t cnt, loff_t *ppos);
ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
			     size_t cnt, loff_t *ppos);
int ftrace_regex_release(struct inode *inode, struct file *file);

void __init
ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);

/* defined in arch */
extern int ftrace_ip_converted(unsigned long ip);
extern int ftrace_dyn_arch_init(void);
extern void ftrace_replace_code(int enable);
extern int ftrace_update_ftrace_func(ftrace_func_t func);
extern void ftrace_caller(void);
extern void ftrace_regs_caller(void);
extern void ftrace_call(void);
extern void ftrace_regs_call(void);
extern void mcount_call(void);

void ftrace_modify_all_code(int command);

#ifndef FTRACE_ADDR
#define FTRACE_ADDR ((unsigned long)ftrace_caller)
#endif

#ifndef FTRACE_GRAPH_ADDR
#define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
#endif

#ifndef FTRACE_REGS_ADDR
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
#else
# define FTRACE_REGS_ADDR FTRACE_ADDR
#endif
#endif

/*
 * If an arch would like functions that are only traced
 * by the function graph tracer to jump directly to its own
 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
 * to be that address to jump to.
 */
#ifndef FTRACE_GRAPH_TRAMP_ADDR
#define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
#endif

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern void ftrace_graph_caller(void);
extern int ftrace_enable_ftrace_graph_caller(void);
extern int ftrace_disable_ftrace_graph_caller(void);
#else
static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
#endif

/**
 * ftrace_make_nop - convert code into nop
 * @mod: module structure if called by module load initialization
 * @rec: the mcount call site record
 * @addr: the address that the call site should be calling
 *
 * This is a very sensitive operation and great care needs
 * to be taken by the arch.  The operation should carefully
 * read the location, check to see if what is read is indeed
 * what we expect it to be, and then on success of the compare,
 * it should write to the location.
 *
 * The code segment at @rec->ip should be a caller to @addr
 *
 * Return must be:
 *  0 on success
 *  -EFAULT on error reading the location
 *  -EINVAL on a failed compare of the contents
 *  -EPERM  on error writing to the location
 * Any other value will be considered a failure.
 */
extern int ftrace_make_nop(struct module *mod,
			   struct dyn_ftrace *rec, unsigned long addr);

/**
 * ftrace_make_call - convert a nop call site into a call to addr
 * @rec: the mcount call site record
 * @addr: the address that the call site should call
 *
 * This is a very sensitive operation and great care needs
 * to be taken by the arch.  The operation should carefully
 * read the location, check to see if what is read is indeed
 * what we expect it to be, and then on success of the compare,
 * it should write to the location.
 *
 * The code segment at @rec->ip should be a nop
 *
 * Return must be:
 *  0 on success
 *  -EFAULT on error reading the location
 *  -EINVAL on a failed compare of the contents
 *  -EPERM  on error writing to the location
 * Any other value will be considered a failure.
 */
extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/**
 * ftrace_modify_call - convert from one addr to another (no nop)
 * @rec: the mcount call site record
 * @old_addr: the address expected to be currently called to
 * @addr: the address to change to
 *
 * This is a very sensitive operation and great care needs
 * to be taken by the arch.  The operation should carefully
 * read the location, check to see if what is read is indeed
 * what we expect it to be, and then on success of the compare,
 * it should write to the location.
 *
 * The code segment at @rec->ip should be a caller to @old_addr
 *
 * Return must be:
 *  0 on success
 *  -EFAULT on error reading the location
 *  -EINVAL on a failed compare of the contents
 *  -EPERM  on error writing to the location
 * Any other value will be considered a failure.
 */
extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
			      unsigned long addr);
#else
/* Should never be called */
static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
				     unsigned long addr)
{
	return -EINVAL;
}
#endif

/* May be defined in arch */
extern int ftrace_arch_read_dyn_info(char *buf, int size);

extern int skip_trace(unsigned long ip);
extern void ftrace_module_init(struct module *mod);
extern void ftrace_module_enable(struct module *mod);
extern void ftrace_release_mod(struct module *mod);

extern void ftrace_disable_daemon(void);
extern void ftrace_enable_daemon(void);
#else /* CONFIG_DYNAMIC_FTRACE */
static inline int skip_trace(unsigned long ip) { return 0; }
static inline int ftrace_force_update(void) { return 0; }
static inline void ftrace_disable_daemon(void) { }
static inline void ftrace_enable_daemon(void) { }
static inline void ftrace_module_init(struct module *mod) { }
static inline void ftrace_module_enable(struct module *mod) { }
static inline void ftrace_release_mod(struct module *mod) { }
static inline int ftrace_text_reserved(const void *start, const void *end)
{
	return 0;
}
static inline unsigned long ftrace_location(unsigned long ip)
{
	return 0;
}

/*
 * Again users of functions that have ftrace_ops may not
 * have them defined when ftrace is not enabled, but these
 * functions may still be called. Use a macro instead of inline.
 */
#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_free_filter(ops) do { } while (0)
#define ftrace_ops_set_global_filter(ops) do { } while (0)

static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
			    size_t cnt, loff_t *ppos) { return -ENODEV; }
static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
			     size_t cnt, loff_t *ppos) { return -ENODEV; }
static inline int
ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }

static inline bool is_ftrace_trampoline(unsigned long addr)
{
	return false;
}
#endif /* CONFIG_DYNAMIC_FTRACE */

/* totally disable ftrace - can not re-enable after this */
void ftrace_kill(void);

static inline void tracer_disable(void)
{
#ifdef CONFIG_FUNCTION_TRACER
	ftrace_enabled = 0;
#endif
}

/*
 * Ftrace disable/restore without lock. Some synchronization mechanism
 * must be used to prevent ftrace_enabled to be changed between
 * disable/restore.
 */
static inline int __ftrace_enabled_save(void)
{
#ifdef CONFIG_FUNCTION_TRACER
	int saved_ftrace_enabled = ftrace_enabled;
	ftrace_enabled = 0;
	return saved_ftrace_enabled;
#else
	return 0;
#endif
}

static inline void __ftrace_enabled_restore(int enabled)
{
#ifdef CONFIG_FUNCTION_TRACER
	ftrace_enabled = enabled;
#endif
}

/* All archs should have this, but we define it for consistency */
#ifndef ftrace_return_address0
# define ftrace_return_address0 __builtin_return_address(0)
#endif

/* Archs may use other ways for ADDR1 and beyond */
#ifndef ftrace_return_address
# ifdef CONFIG_FRAME_POINTER
#  define ftrace_return_address(n) __builtin_return_address(n)
# else
#  define ftrace_return_address(n) 0UL
# endif
#endif

#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))

static inline unsigned long get_lock_parent_ip(void)
{
	unsigned long addr = CALLER_ADDR0;

	if (!in_lock_functions(addr))
		return addr;
	addr = CALLER_ADDR1;
	if (!in_lock_functions(addr))
		return addr;
	return CALLER_ADDR2;
}

#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
#else
/*
 * Use defines instead of static inlines because some arches will make code out
 * of the CALLER_ADDR, when we really want these to be a real nop.
 */
# define trace_preempt_on(a0, a1) do { } while (0)
# define trace_preempt_off(a0, a1) do { } while (0)
#endif

#ifdef CONFIG_FTRACE_MCOUNT_RECORD
extern void ftrace_init(void);
#else
static inline void ftrace_init(void) { }
#endif

/*
 * Structure that defines an entry function trace.
 * It's already packed but the attribute "packed" is needed
 * to remove extra padding at the end.
 */
struct ftrace_graph_ent {
	unsigned long func; /* Current function */
	int depth;
} __packed;

/*
 * Structure that defines a return function trace.
 * It's already packed but the attribute "packed" is needed
 * to remove extra padding at the end.
 */
struct ftrace_graph_ret {
	unsigned long func; /* Current function */
	/* Number of functions that overran the depth limit for current task */
	unsigned long overrun;
	unsigned long long calltime;
	unsigned long long rettime;
	int depth;
} __packed;

/* Type of the callback handlers for tracing function graph*/
typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

/*
 * Stack of return addresses for functions
 * of a thread.
 * Used in struct thread_info
 */
struct ftrace_ret_stack {
	unsigned long ret;
	unsigned long func;
	unsigned long long calltime;
#ifdef CONFIG_FUNCTION_PROFILER
	unsigned long long subtime;
#endif
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
	unsigned long fp;
#endif
#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
	unsigned long *retp;
#endif
};

/*
 * Primary handler of a function return.
 * It relays on ftrace_return_to_handler.
 * Defined in entry_32/64.S
 */
extern void return_to_handler(void);

extern int
function_graph_enter(unsigned long ret, unsigned long func,
		     unsigned long frame_pointer, unsigned long *retp);

unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
				    unsigned long ret, unsigned long *retp);

/*
 * Sometimes we don't want to trace a function with the function
 * graph tracer but we want them to keep traced by the usual function
 * tracer if the function graph tracer is not configured.
 */
#define __notrace_funcgraph		notrace

#define FTRACE_NOTRACE_DEPTH 65536
#define FTRACE_RETFUNC_DEPTH 50
#define FTRACE_RETSTACK_ALLOC_SIZE 32
extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
				trace_func_graph_ent_t entryfunc);

extern bool ftrace_graph_is_dead(void);
extern void ftrace_graph_stop(void);

/* The current handlers in use */
extern trace_func_graph_ret_t ftrace_graph_return;
extern trace_func_graph_ent_t ftrace_graph_entry;

extern void unregister_ftrace_graph(void);

extern void ftrace_graph_init_task(struct task_struct *t);
extern void ftrace_graph_exit_task(struct task_struct *t);
extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);

static inline int task_curr_ret_stack(struct task_struct *t)
{
	return t->curr_ret_stack;
}

static inline void pause_graph_tracing(void)
{
	atomic_inc(&current->tracing_graph_pause);
}

static inline void unpause_graph_tracing(void)
{
	atomic_dec(&current->tracing_graph_pause);
}
#else /* !CONFIG_FUNCTION_GRAPH_TRACER */

#define __notrace_funcgraph

static inline void ftrace_graph_init_task(struct task_struct *t) { }
static inline void ftrace_graph_exit_task(struct task_struct *t) { }
static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }

static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
			  trace_func_graph_ent_t entryfunc)
{
	return -1;
}
static inline void unregister_ftrace_graph(void) { }

static inline int task_curr_ret_stack(struct task_struct *tsk)
{
	return -1;
}

static inline unsigned long
ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
		      unsigned long *retp)
{
	return ret;
}

static inline void pause_graph_tracing(void) { }
static inline void unpause_graph_tracing(void) { }
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

#ifdef CONFIG_TRACING

/* flags for current->trace */
enum {
	TSK_TRACE_FL_TRACE_BIT	= 0,
	TSK_TRACE_FL_GRAPH_BIT	= 1,
};
enum {
	TSK_TRACE_FL_TRACE	= 1 << TSK_TRACE_FL_TRACE_BIT,
	TSK_TRACE_FL_GRAPH	= 1 << TSK_TRACE_FL_GRAPH_BIT,
};

static inline void set_tsk_trace_trace(struct task_struct *tsk)
{
	set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
}

static inline void clear_tsk_trace_trace(struct task_struct *tsk)
{
	clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
}

static inline int test_tsk_trace_trace(struct task_struct *tsk)
{
	return tsk->trace & TSK_TRACE_FL_TRACE;
}

static inline void set_tsk_trace_graph(struct task_struct *tsk)
{
	set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
}

static inline void clear_tsk_trace_graph(struct task_struct *tsk)
{
	clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
}

static inline int test_tsk_trace_graph(struct task_struct *tsk)
{
	return tsk->trace & TSK_TRACE_FL_GRAPH;
}

enum ftrace_dump_mode;

extern enum ftrace_dump_mode ftrace_dump_on_oops;
extern int tracepoint_printk;

extern void disable_trace_on_warning(void);
extern int __disable_trace_on_warning;

int tracepoint_printk_sysctl(struct ctl_table *table, int write,
			     void __user *buffer, size_t *lenp,
			     loff_t *ppos);

#else /* CONFIG_TRACING */
static inline void  disable_trace_on_warning(void) { }
#endif /* CONFIG_TRACING */

#ifdef CONFIG_FTRACE_SYSCALLS

unsigned long arch_syscall_addr(int nr);

#endif /* CONFIG_FTRACE_SYSCALLS */

#endif /* _LINUX_FTRACE_H */