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1408 serge 1
/*
2
 * Runtime locking correctness validator
3
 *
4
 *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar 
5
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra 
6
 *
7
 * see Documentation/lockdep-design.txt for more details.
8
 */
9
#ifndef __LINUX_LOCKDEP_H
10
#define __LINUX_LOCKDEP_H
11
 
12
struct task_struct;
13
struct lockdep_map;
14
 
15
#ifdef CONFIG_LOCKDEP
16
 
17
#include 
18
#include 
19
#include 
20
#include 
21
 
22
/*
23
 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
24
 * the total number of states... :-(
25
 */
26
#define XXX_LOCK_USAGE_STATES		(1+3*4)
27
 
28
#define MAX_LOCKDEP_SUBCLASSES		8UL
29
 
30
/*
1964 serge 31
 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
32
 * cached in the instance of lockdep_map
33
 *
34
 * Currently main class (subclass == 0) and signle depth subclass
35
 * are cached in lockdep_map. This optimization is mainly targeting
36
 * on rq->lock. double_rq_lock() acquires this highly competitive with
37
 * single depth.
38
 */
39
#define NR_LOCKDEP_CACHING_CLASSES	2
40
 
41
/*
1408 serge 42
 * Lock-classes are keyed via unique addresses, by embedding the
43
 * lockclass-key into the kernel (or module) .data section. (For
44
 * static locks we use the lock address itself as the key.)
45
 */
46
struct lockdep_subclass_key {
47
	char __one_byte;
48
} __attribute__ ((__packed__));
49
 
50
struct lock_class_key {
51
	struct lockdep_subclass_key	subkeys[MAX_LOCKDEP_SUBCLASSES];
52
};
53
 
54
#define LOCKSTAT_POINTS		4
55
 
56
/*
57
 * The lock-class itself:
58
 */
59
struct lock_class {
60
	/*
61
	 * class-hash:
62
	 */
63
	struct list_head		hash_entry;
64
 
65
	/*
66
	 * global list of all lock-classes:
67
	 */
68
	struct list_head		lock_entry;
69
 
70
	struct lockdep_subclass_key	*key;
71
	unsigned int			subclass;
72
	unsigned int			dep_gen_id;
73
 
74
	/*
75
	 * IRQ/softirq usage tracking bits:
76
	 */
77
	unsigned long			usage_mask;
78
	struct stack_trace		usage_traces[XXX_LOCK_USAGE_STATES];
79
 
80
	/*
81
	 * These fields represent a directed graph of lock dependencies,
82
	 * to every node we attach a list of "forward" and a list of
83
	 * "backward" graph nodes.
84
	 */
85
	struct list_head		locks_after, locks_before;
86
 
87
	/*
88
	 * Generation counter, when doing certain classes of graph walking,
89
	 * to ensure that we check one node only once:
90
	 */
91
	unsigned int			version;
92
 
93
	/*
94
	 * Statistics counter:
95
	 */
96
	unsigned long			ops;
97
 
98
	const char			*name;
99
	int				name_version;
100
 
101
#ifdef CONFIG_LOCK_STAT
102
	unsigned long			contention_point[LOCKSTAT_POINTS];
103
	unsigned long			contending_point[LOCKSTAT_POINTS];
104
#endif
105
};
106
 
107
#ifdef CONFIG_LOCK_STAT
108
struct lock_time {
109
	s64				min;
110
	s64				max;
111
	s64				total;
112
	unsigned long			nr;
113
};
114
 
115
enum bounce_type {
116
	bounce_acquired_write,
117
	bounce_acquired_read,
118
	bounce_contended_write,
119
	bounce_contended_read,
120
	nr_bounce_types,
121
 
122
	bounce_acquired = bounce_acquired_write,
123
	bounce_contended = bounce_contended_write,
124
};
125
 
126
struct lock_class_stats {
127
	unsigned long			contention_point[4];
128
	unsigned long			contending_point[4];
129
	struct lock_time		read_waittime;
130
	struct lock_time		write_waittime;
131
	struct lock_time		read_holdtime;
132
	struct lock_time		write_holdtime;
133
	unsigned long			bounces[nr_bounce_types];
134
};
135
 
136
struct lock_class_stats lock_stats(struct lock_class *class);
137
void clear_lock_stats(struct lock_class *class);
138
#endif
139
 
140
/*
141
 * Map the lock object (the lock instance) to the lock-class object.
142
 * This is embedded into specific lock instances:
143
 */
144
struct lockdep_map {
145
	struct lock_class_key		*key;
1964 serge 146
	struct lock_class		*class_cache[NR_LOCKDEP_CACHING_CLASSES];
1408 serge 147
	const char			*name;
148
#ifdef CONFIG_LOCK_STAT
149
	int				cpu;
150
	unsigned long			ip;
151
#endif
152
};
153
 
154
/*
155
 * Every lock has a list of other locks that were taken after it.
156
 * We only grow the list, never remove from it:
157
 */
158
struct lock_list {
159
	struct list_head		entry;
160
	struct lock_class		*class;
161
	struct stack_trace		trace;
162
	int				distance;
163
 
164
	/*
165
	 * The parent field is used to implement breadth-first search, and the
166
	 * bit 0 is reused to indicate if the lock has been accessed in BFS.
167
	 */
168
	struct lock_list		*parent;
169
};
170
 
171
/*
172
 * We record lock dependency chains, so that we can cache them:
173
 */
174
struct lock_chain {
175
	u8				irq_context;
176
	u8				depth;
177
	u16				base;
178
	struct list_head		entry;
179
	u64				chain_key;
180
};
181
 
182
#define MAX_LOCKDEP_KEYS_BITS		13
183
/*
184
 * Subtract one because we offset hlock->class_idx by 1 in order
185
 * to make 0 mean no class. This avoids overflowing the class_idx
186
 * bitfield and hitting the BUG in hlock_class().
187
 */
188
#define MAX_LOCKDEP_KEYS		((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
189
 
190
struct held_lock {
191
	/*
192
	 * One-way hash of the dependency chain up to this point. We
193
	 * hash the hashes step by step as the dependency chain grows.
194
	 *
195
	 * We use it for dependency-caching and we skip detection
196
	 * passes and dependency-updates if there is a cache-hit, so
197
	 * it is absolutely critical for 100% coverage of the validator
198
	 * to have a unique key value for every unique dependency path
199
	 * that can occur in the system, to make a unique hash value
200
	 * as likely as possible - hence the 64-bit width.
201
	 *
202
	 * The task struct holds the current hash value (initialized
203
	 * with zero), here we store the previous hash value:
204
	 */
205
	u64				prev_chain_key;
206
	unsigned long			acquire_ip;
207
	struct lockdep_map		*instance;
208
	struct lockdep_map		*nest_lock;
209
#ifdef CONFIG_LOCK_STAT
210
	u64 				waittime_stamp;
211
	u64				holdtime_stamp;
212
#endif
213
	unsigned int			class_idx:MAX_LOCKDEP_KEYS_BITS;
214
	/*
215
	 * The lock-stack is unified in that the lock chains of interrupt
216
	 * contexts nest ontop of process context chains, but we 'separate'
217
	 * the hashes by starting with 0 if we cross into an interrupt
218
	 * context, and we also keep do not add cross-context lock
219
	 * dependencies - the lock usage graph walking covers that area
220
	 * anyway, and we'd just unnecessarily increase the number of
221
	 * dependencies otherwise. [Note: hardirq and softirq contexts
222
	 * are separated from each other too.]
223
	 *
224
	 * The following field is used to detect when we cross into an
225
	 * interrupt context:
226
	 */
227
	unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
228
	unsigned int trylock:1;						/* 16 bits */
229
 
230
	unsigned int read:2;        /* see lock_acquire() comment */
231
	unsigned int check:2;       /* see lock_acquire() comment */
232
	unsigned int hardirqs_off:1;
233
	unsigned int references:11;					/* 32 bits */
234
};
235
 
236
/*
237
 * Initialization, self-test and debugging-output methods:
238
 */
239
extern void lockdep_init(void);
240
extern void lockdep_info(void);
241
extern void lockdep_reset(void);
242
extern void lockdep_reset_lock(struct lockdep_map *lock);
243
extern void lockdep_free_key_range(void *start, unsigned long size);
244
extern void lockdep_sys_exit(void);
245
 
246
extern void lockdep_off(void);
247
extern void lockdep_on(void);
248
 
249
/*
250
 * These methods are used by specific locking variants (spinlocks,
251
 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
252
 * to lockdep:
253
 */
254
 
255
extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
256
			     struct lock_class_key *key, int subclass);
257
 
258
/*
259
 * To initialize a lockdep_map statically use this macro.
260
 * Note that _name must not be NULL.
261
 */
262
#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
263
	{ .name = (_name), .key = (void *)(_key), }
264
 
265
/*
266
 * Reinitialize a lock key - for cases where there is special locking or
267
 * special initialization of locks so that the validator gets the scope
268
 * of dependencies wrong: they are either too broad (they need a class-split)
269
 * or they are too narrow (they suffer from a false class-split):
270
 */
271
#define lockdep_set_class(lock, key) \
272
		lockdep_init_map(&(lock)->dep_map, #key, key, 0)
273
#define lockdep_set_class_and_name(lock, key, name) \
274
		lockdep_init_map(&(lock)->dep_map, name, key, 0)
275
#define lockdep_set_class_and_subclass(lock, key, sub) \
276
		lockdep_init_map(&(lock)->dep_map, #key, key, sub)
277
#define lockdep_set_subclass(lock, sub)	\
278
		lockdep_init_map(&(lock)->dep_map, #lock, \
279
				 (lock)->dep_map.key, sub)
1964 serge 280
 
281
#define lockdep_set_novalidate_class(lock) \
282
	lockdep_set_class(lock, &__lockdep_no_validate__)
1408 serge 283
/*
284
 * Compare locking classes
285
 */
286
#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
287
 
288
static inline int lockdep_match_key(struct lockdep_map *lock,
289
				    struct lock_class_key *key)
290
{
291
	return lock->key == key;
292
}
293
 
294
/*
295
 * Acquire a lock.
296
 *
297
 * Values for "read":
298
 *
299
 *   0: exclusive (write) acquire
300
 *   1: read-acquire (no recursion allowed)
301
 *   2: read-acquire with same-instance recursion allowed
302
 *
303
 * Values for check:
304
 *
305
 *   0: disabled
306
 *   1: simple checks (freeing, held-at-exit-time, etc.)
307
 *   2: full validation
308
 */
309
extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
310
			 int trylock, int read, int check,
311
			 struct lockdep_map *nest_lock, unsigned long ip);
312
 
313
extern void lock_release(struct lockdep_map *lock, int nested,
314
			 unsigned long ip);
315
 
316
#define lockdep_is_held(lock)	lock_is_held(&(lock)->dep_map)
317
 
318
extern int lock_is_held(struct lockdep_map *lock);
319
 
320
extern void lock_set_class(struct lockdep_map *lock, const char *name,
321
			   struct lock_class_key *key, unsigned int subclass,
322
			   unsigned long ip);
323
 
324
static inline void lock_set_subclass(struct lockdep_map *lock,
325
		unsigned int subclass, unsigned long ip)
326
{
327
	lock_set_class(lock, lock->name, lock->key, subclass, ip);
328
}
329
 
330
extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
331
extern void lockdep_clear_current_reclaim_state(void);
332
extern void lockdep_trace_alloc(gfp_t mask);
333
 
334
# define INIT_LOCKDEP				.lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
335
 
336
#define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
337
 
338
#define lockdep_assert_held(l)	WARN_ON(debug_locks && !lockdep_is_held(l))
339
 
340
#else /* !LOCKDEP */
341
 
342
static inline void lockdep_off(void)
343
{
344
}
345
 
346
static inline void lockdep_on(void)
347
{
348
}
349
 
350
# define lock_acquire(l, s, t, r, c, n, i)	do { } while (0)
351
# define lock_release(l, n, i)			do { } while (0)
352
# define lock_set_class(l, n, k, s, i)		do { } while (0)
353
# define lock_set_subclass(l, s, i)		do { } while (0)
354
# define lockdep_set_current_reclaim_state(g)	do { } while (0)
355
# define lockdep_clear_current_reclaim_state()	do { } while (0)
356
# define lockdep_trace_alloc(g)			do { } while (0)
357
# define lockdep_init()				do { } while (0)
358
# define lockdep_info()				do { } while (0)
359
# define lockdep_init_map(lock, name, key, sub) \
360
		do { (void)(name); (void)(key); } while (0)
361
# define lockdep_set_class(lock, key)		do { (void)(key); } while (0)
362
# define lockdep_set_class_and_name(lock, key, name) \
363
		do { (void)(key); (void)(name); } while (0)
364
#define lockdep_set_class_and_subclass(lock, key, sub) \
365
		do { (void)(key); } while (0)
366
#define lockdep_set_subclass(lock, sub)		do { } while (0)
1964 serge 367
 
368
#define lockdep_set_novalidate_class(lock) do { } while (0)
369
 
1408 serge 370
/*
371
 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
372
 * case since the result is not well defined and the caller should rather
373
 * #ifdef the call himself.
374
 */
375
 
376
# define INIT_LOCKDEP
377
# define lockdep_reset()		do { debug_locks = 1; } while (0)
378
# define lockdep_free_key_range(start, size)	do { } while (0)
379
# define lockdep_sys_exit() 			do { } while (0)
380
/*
381
 * The class key takes no space if lockdep is disabled:
382
 */
383
struct lock_class_key { };
384
 
385
#define lockdep_depth(tsk)	(0)
386
 
387
#define lockdep_assert_held(l)			do { } while (0)
388
 
389
#endif /* !LOCKDEP */
390
 
391
#ifdef CONFIG_LOCK_STAT
392
 
393
extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
394
extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
395
 
396
#define LOCK_CONTENDED(_lock, try, lock)			\
397
do {								\
398
	if (!try(_lock)) {					\
399
		lock_contended(&(_lock)->dep_map, _RET_IP_);	\
400
		lock(_lock);					\
401
	}							\
402
	lock_acquired(&(_lock)->dep_map, _RET_IP_);			\
403
} while (0)
404
 
405
#else /* CONFIG_LOCK_STAT */
406
 
407
#define lock_contended(lockdep_map, ip) do {} while (0)
408
#define lock_acquired(lockdep_map, ip) do {} while (0)
409
 
410
#define LOCK_CONTENDED(_lock, try, lock) \
411
	lock(_lock)
412
 
413
#endif /* CONFIG_LOCK_STAT */
414
 
415
#ifdef CONFIG_LOCKDEP
416
 
417
/*
418
 * On lockdep we dont want the hand-coded irq-enable of
419
 * _raw_*_lock_flags() code, because lockdep assumes
420
 * that interrupts are not re-enabled during lock-acquire:
421
 */
422
#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
423
	LOCK_CONTENDED((_lock), (try), (lock))
424
 
425
#else /* CONFIG_LOCKDEP */
426
 
427
#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
428
	lockfl((_lock), (flags))
429
 
430
#endif /* CONFIG_LOCKDEP */
431
 
432
#ifdef CONFIG_TRACE_IRQFLAGS
433
extern void print_irqtrace_events(struct task_struct *curr);
434
#else
435
static inline void print_irqtrace_events(struct task_struct *curr)
436
{
437
}
438
#endif
439
 
440
/*
441
 * For trivial one-depth nesting of a lock-class, the following
442
 * global define can be used. (Subsystems with multiple levels
443
 * of nesting should define their own lock-nesting subclasses.)
444
 */
445
#define SINGLE_DEPTH_NESTING			1
446
 
447
/*
448
 * Map the dependency ops to NOP or to real lockdep ops, depending
449
 * on the per lock-class debug mode:
450
 */
451
 
452
#ifdef CONFIG_DEBUG_LOCK_ALLOC
453
# ifdef CONFIG_PROVE_LOCKING
454
#  define spin_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
455
#  define spin_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 2, n, i)
456
# else
457
#  define spin_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
458
#  define spin_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 1, NULL, i)
459
# endif
460
# define spin_release(l, n, i)			lock_release(l, n, i)
461
#else
462
# define spin_acquire(l, s, t, i)		do { } while (0)
463
# define spin_release(l, n, i)			do { } while (0)
464
#endif
465
 
466
#ifdef CONFIG_DEBUG_LOCK_ALLOC
467
# ifdef CONFIG_PROVE_LOCKING
468
#  define rwlock_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
469
#  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 2, NULL, i)
470
# else
471
#  define rwlock_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
472
#  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 1, NULL, i)
473
# endif
474
# define rwlock_release(l, n, i)		lock_release(l, n, i)
475
#else
476
# define rwlock_acquire(l, s, t, i)		do { } while (0)
477
# define rwlock_acquire_read(l, s, t, i)	do { } while (0)
478
# define rwlock_release(l, n, i)		do { } while (0)
479
#endif
480
 
481
#ifdef CONFIG_DEBUG_LOCK_ALLOC
482
# ifdef CONFIG_PROVE_LOCKING
483
#  define mutex_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
1970 serge 484
#  define mutex_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 2, n, i)
1408 serge 485
# else
486
#  define mutex_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
1970 serge 487
#  define mutex_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 1, n, i)
1408 serge 488
# endif
489
# define mutex_release(l, n, i)			lock_release(l, n, i)
490
#else
491
# define mutex_acquire(l, s, t, i)		do { } while (0)
1970 serge 492
# define mutex_acquire_nest(l, s, t, n, i)	do { } while (0)
1408 serge 493
# define mutex_release(l, n, i)			do { } while (0)
494
#endif
495
 
496
#ifdef CONFIG_DEBUG_LOCK_ALLOC
497
# ifdef CONFIG_PROVE_LOCKING
498
#  define rwsem_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
499
#  define rwsem_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 1, 2, NULL, i)
500
# else
501
#  define rwsem_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
502
#  define rwsem_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 1, 1, NULL, i)
503
# endif
504
# define rwsem_release(l, n, i)			lock_release(l, n, i)
505
#else
506
# define rwsem_acquire(l, s, t, i)		do { } while (0)
507
# define rwsem_acquire_read(l, s, t, i)		do { } while (0)
508
# define rwsem_release(l, n, i)			do { } while (0)
509
#endif
510
 
511
#ifdef CONFIG_DEBUG_LOCK_ALLOC
512
# ifdef CONFIG_PROVE_LOCKING
513
#  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
1970 serge 514
#  define lock_map_acquire_read(l)	lock_acquire(l, 0, 0, 2, 2, NULL, _THIS_IP_)
1408 serge 515
# else
516
#  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
1970 serge 517
#  define lock_map_acquire_read(l)	lock_acquire(l, 0, 0, 2, 1, NULL, _THIS_IP_)
1408 serge 518
# endif
519
# define lock_map_release(l)			lock_release(l, 1, _THIS_IP_)
520
#else
521
# define lock_map_acquire(l)			do { } while (0)
1970 serge 522
# define lock_map_acquire_read(l)		do { } while (0)
1408 serge 523
# define lock_map_release(l)			do { } while (0)
524
#endif
525
 
526
#ifdef CONFIG_PROVE_LOCKING
527
# define might_lock(lock) 						\
528
do {									\
529
	typecheck(struct lockdep_map *, &(lock)->dep_map);		\
530
	lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_);	\
531
	lock_release(&(lock)->dep_map, 0, _THIS_IP_);			\
532
} while (0)
533
# define might_lock_read(lock) 						\
534
do {									\
535
	typecheck(struct lockdep_map *, &(lock)->dep_map);		\
536
	lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_);	\
537
	lock_release(&(lock)->dep_map, 0, _THIS_IP_);			\
538
} while (0)
539
#else
540
# define might_lock(lock) do { } while (0)
541
# define might_lock_read(lock) do { } while (0)
542
#endif
543
 
1964 serge 544
#ifdef CONFIG_PROVE_RCU
2967 Serge 545
void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
1964 serge 546
#endif
547
 
1408 serge 548
#endif /* __LINUX_LOCKDEP_H */