2 * Runtime locking correctness validator
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>
7 * see Documentation/lockdep-design.txt for more details.
9 #ifndef __LINUX_LOCKDEP_H
10 #define __LINUX_LOCKDEP_H
17 #include <linux/linkage.h>
18 #include <linux/list.h>
19 #include <linux/debug_locks.h>
20 #include <linux/stacktrace.h>
23 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
24 * the total number of states... :-(
26 #define XXX_LOCK_USAGE_STATES (1+3*4)
28 #define MAX_LOCKDEP_SUBCLASSES 8UL
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.)
35 struct lockdep_subclass_key {
37 } __attribute__ ((__packed__));
39 struct lock_class_key {
40 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
43 #define LOCKSTAT_POINTS 4
46 * The lock-class itself:
52 struct list_head hash_entry;
55 * global list of all lock-classes:
57 struct list_head lock_entry;
59 struct lockdep_subclass_key *key;
60 unsigned int subclass;
61 unsigned int dep_gen_id;
64 * IRQ/softirq usage tracking bits:
66 unsigned long usage_mask;
67 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
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.
74 struct list_head locks_after, locks_before;
77 * Generation counter, when doing certain classes of graph walking,
78 * to ensure that we check one node only once:
90 #ifdef CONFIG_LOCK_STAT
91 unsigned long contention_point[LOCKSTAT_POINTS];
92 unsigned long contending_point[LOCKSTAT_POINTS];
96 #ifdef CONFIG_LOCK_STAT
105 bounce_acquired_write,
106 bounce_acquired_read,
107 bounce_contended_write,
108 bounce_contended_read,
111 bounce_acquired = bounce_acquired_write,
112 bounce_contended = bounce_contended_write,
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];
125 struct lock_class_stats lock_stats(struct lock_class *class);
126 void clear_lock_stats(struct lock_class *class);
130 * Map the lock object (the lock instance) to the lock-class object.
131 * This is embedded into specific lock instances:
134 struct lock_class_key *key;
135 struct lock_class *class_cache;
137 #ifdef CONFIG_LOCK_STAT
144 * Every lock has a list of other locks that were taken after it.
145 * We only grow the list, never remove from it:
148 struct list_head entry;
149 struct lock_class *class;
150 struct stack_trace trace;
153 /*The parent field is used to implement breadth-first search,and
154 *the bit 0 is reused to indicate if the lock has been accessed
157 struct lock_list *parent;
161 * We record lock dependency chains, so that we can cache them:
167 struct list_head entry;
171 #define MAX_LOCKDEP_KEYS_BITS 13
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().
177 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
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.
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.
191 * The task struct holds the current hash value (initialized
192 * with zero), here we store the previous hash value:
195 unsigned long acquire_ip;
196 struct lockdep_map *instance;
197 struct lockdep_map *nest_lock;
198 #ifdef CONFIG_LOCK_STAT
202 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
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.]
213 * The following field is used to detect when we cross into an
216 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
217 unsigned int trylock:1;
218 unsigned int read:2; /* see lock_acquire() comment */
219 unsigned int check:2; /* see lock_acquire() comment */
220 unsigned int hardirqs_off:1;
224 * Initialization, self-test and debugging-output methods:
226 extern void lockdep_init(void);
227 extern void lockdep_info(void);
228 extern void lockdep_reset(void);
229 extern void lockdep_reset_lock(struct lockdep_map *lock);
230 extern void lockdep_free_key_range(void *start, unsigned long size);
231 extern void lockdep_sys_exit(void);
233 extern void lockdep_off(void);
234 extern void lockdep_on(void);
237 * These methods are used by specific locking variants (spinlocks,
238 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
242 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
243 struct lock_class_key *key, int subclass);
246 * To initialize a lockdep_map statically use this macro.
247 * Note that _name must not be NULL.
249 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
250 { .name = (_name), .key = (void *)(_key), }
253 * Reinitialize a lock key - for cases where there is special locking or
254 * special initialization of locks so that the validator gets the scope
255 * of dependencies wrong: they are either too broad (they need a class-split)
256 * or they are too narrow (they suffer from a false class-split):
258 #define lockdep_set_class(lock, key) \
259 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
260 #define lockdep_set_class_and_name(lock, key, name) \
261 lockdep_init_map(&(lock)->dep_map, name, key, 0)
262 #define lockdep_set_class_and_subclass(lock, key, sub) \
263 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
264 #define lockdep_set_subclass(lock, sub) \
265 lockdep_init_map(&(lock)->dep_map, #lock, \
266 (lock)->dep_map.key, sub)
268 * Compare locking classes
270 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
272 static inline int lockdep_match_key(struct lockdep_map *lock,
273 struct lock_class_key *key)
275 return lock->key == key;
283 * 0: exclusive (write) acquire
284 * 1: read-acquire (no recursion allowed)
285 * 2: read-acquire with same-instance recursion allowed
290 * 1: simple checks (freeing, held-at-exit-time, etc.)
293 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
294 int trylock, int read, int check,
295 struct lockdep_map *nest_lock, unsigned long ip);
297 extern void lock_release(struct lockdep_map *lock, int nested,
300 extern void lock_set_class(struct lockdep_map *lock, const char *name,
301 struct lock_class_key *key, unsigned int subclass,
304 static inline void lock_set_subclass(struct lockdep_map *lock,
305 unsigned int subclass, unsigned long ip)
307 lock_set_class(lock, lock->name, lock->key, subclass, ip);
310 extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
311 extern void lockdep_clear_current_reclaim_state(void);
312 extern void lockdep_trace_alloc(gfp_t mask);
314 # define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
316 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
320 static inline void lockdep_off(void)
324 static inline void lockdep_on(void)
328 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
329 # define lock_release(l, n, i) do { } while (0)
330 # define lock_set_class(l, n, k, s, i) do { } while (0)
331 # define lock_set_subclass(l, s, i) do { } while (0)
332 # define lockdep_set_current_reclaim_state(g) do { } while (0)
333 # define lockdep_clear_current_reclaim_state() do { } while (0)
334 # define lockdep_trace_alloc(g) do { } while (0)
335 # define lockdep_init() do { } while (0)
336 # define lockdep_info() do { } while (0)
337 # define lockdep_init_map(lock, name, key, sub) \
338 do { (void)(name); (void)(key); } while (0)
339 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
340 # define lockdep_set_class_and_name(lock, key, name) \
341 do { (void)(key); (void)(name); } while (0)
342 #define lockdep_set_class_and_subclass(lock, key, sub) \
343 do { (void)(key); } while (0)
344 #define lockdep_set_subclass(lock, sub) do { } while (0)
346 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
347 * case since the result is not well defined and the caller should rather
348 * #ifdef the call himself.
351 # define INIT_LOCKDEP
352 # define lockdep_reset() do { debug_locks = 1; } while (0)
353 # define lockdep_free_key_range(start, size) do { } while (0)
354 # define lockdep_sys_exit() do { } while (0)
356 * The class key takes no space if lockdep is disabled:
358 struct lock_class_key { };
360 #define lockdep_depth(tsk) (0)
362 #endif /* !LOCKDEP */
364 #ifdef CONFIG_LOCK_STAT
366 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
367 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
369 #define LOCK_CONTENDED(_lock, try, lock) \
372 lock_contended(&(_lock)->dep_map, _RET_IP_); \
375 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
378 #else /* CONFIG_LOCK_STAT */
380 #define lock_contended(lockdep_map, ip) do {} while (0)
381 #define lock_acquired(lockdep_map, ip) do {} while (0)
383 #define LOCK_CONTENDED(_lock, try, lock) \
386 #endif /* CONFIG_LOCK_STAT */
388 #ifdef CONFIG_LOCKDEP
391 * On lockdep we dont want the hand-coded irq-enable of
392 * _raw_*_lock_flags() code, because lockdep assumes
393 * that interrupts are not re-enabled during lock-acquire:
395 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
396 LOCK_CONTENDED((_lock), (try), (lock))
398 #else /* CONFIG_LOCKDEP */
400 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
401 lockfl((_lock), (flags))
403 #endif /* CONFIG_LOCKDEP */
405 #ifdef CONFIG_GENERIC_HARDIRQS
406 extern void early_init_irq_lock_class(void);
408 static inline void early_init_irq_lock_class(void)
413 #ifdef CONFIG_TRACE_IRQFLAGS
414 extern void early_boot_irqs_off(void);
415 extern void early_boot_irqs_on(void);
416 extern void print_irqtrace_events(struct task_struct *curr);
418 static inline void early_boot_irqs_off(void)
421 static inline void early_boot_irqs_on(void)
424 static inline void print_irqtrace_events(struct task_struct *curr)
430 * For trivial one-depth nesting of a lock-class, the following
431 * global define can be used. (Subsystems with multiple levels
432 * of nesting should define their own lock-nesting subclasses.)
434 #define SINGLE_DEPTH_NESTING 1
437 * Map the dependency ops to NOP or to real lockdep ops, depending
438 * on the per lock-class debug mode:
441 #ifdef CONFIG_DEBUG_LOCK_ALLOC
442 # ifdef CONFIG_PROVE_LOCKING
443 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
444 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i)
446 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
447 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i)
449 # define spin_release(l, n, i) lock_release(l, n, i)
451 # define spin_acquire(l, s, t, i) do { } while (0)
452 # define spin_release(l, n, i) do { } while (0)
455 #ifdef CONFIG_DEBUG_LOCK_ALLOC
456 # ifdef CONFIG_PROVE_LOCKING
457 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
458 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i)
460 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
461 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i)
463 # define rwlock_release(l, n, i) lock_release(l, n, i)
465 # define rwlock_acquire(l, s, t, i) do { } while (0)
466 # define rwlock_acquire_read(l, s, t, i) do { } while (0)
467 # define rwlock_release(l, n, i) do { } while (0)
470 #ifdef CONFIG_DEBUG_LOCK_ALLOC
471 # ifdef CONFIG_PROVE_LOCKING
472 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
474 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
476 # define mutex_release(l, n, i) lock_release(l, n, i)
478 # define mutex_acquire(l, s, t, i) do { } while (0)
479 # define mutex_release(l, n, i) do { } while (0)
482 #ifdef CONFIG_DEBUG_LOCK_ALLOC
483 # ifdef CONFIG_PROVE_LOCKING
484 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
485 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i)
487 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
488 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i)
490 # define rwsem_release(l, n, i) lock_release(l, n, i)
492 # define rwsem_acquire(l, s, t, i) do { } while (0)
493 # define rwsem_acquire_read(l, s, t, i) do { } while (0)
494 # define rwsem_release(l, n, i) do { } while (0)
497 #ifdef CONFIG_DEBUG_LOCK_ALLOC
498 # ifdef CONFIG_PROVE_LOCKING
499 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
501 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
503 # define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
505 # define lock_map_acquire(l) do { } while (0)
506 # define lock_map_release(l) do { } while (0)
509 #ifdef CONFIG_PROVE_LOCKING
510 # define might_lock(lock) \
512 typecheck(struct lockdep_map *, &(lock)->dep_map); \
513 lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
514 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
516 # define might_lock_read(lock) \
518 typecheck(struct lockdep_map *, &(lock)->dep_map); \
519 lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
520 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
523 # define might_lock(lock) do { } while (0)
524 # define might_lock_read(lock) do { } while (0)
527 #endif /* __LINUX_LOCKDEP_H */