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