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 * Lock-class usage-state bits:
30 LOCK_USED_IN_RECLAIM_FS,
33 LOCK_ENABLED_RECLAIM_FS,
34 LOCK_USED_IN_HARDIRQ_READ,
35 LOCK_USED_IN_SOFTIRQ_READ,
36 LOCK_USED_IN_RECLAIM_FS_READ,
37 LOCK_ENABLED_SOFTIRQ_READ,
38 LOCK_ENABLED_HARDIRQ_READ,
39 LOCK_ENABLED_RECLAIM_FS_READ,
44 * Usage-state bitmasks:
46 #define LOCKF_USED (1 << LOCK_USED)
47 #define LOCKF_USED_IN_HARDIRQ (1 << LOCK_USED_IN_HARDIRQ)
48 #define LOCKF_USED_IN_SOFTIRQ (1 << LOCK_USED_IN_SOFTIRQ)
49 #define LOCKF_USED_IN_RECLAIM_FS (1 << LOCK_USED_IN_RECLAIM_FS)
50 #define LOCKF_ENABLED_HARDIRQ (1 << LOCK_ENABLED_HARDIRQ)
51 #define LOCKF_ENABLED_SOFTIRQ (1 << LOCK_ENABLED_SOFTIRQ)
52 #define LOCKF_ENABLED_RECLAIM_FS (1 << LOCK_ENABLED_RECLAIM_FS)
54 #define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
55 #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
57 #define LOCKF_USED_IN_HARDIRQ_READ (1 << LOCK_USED_IN_HARDIRQ_READ)
58 #define LOCKF_USED_IN_SOFTIRQ_READ (1 << LOCK_USED_IN_SOFTIRQ_READ)
59 #define LOCKF_USED_IN_RECLAIM_FS_READ (1 << LOCK_USED_IN_RECLAIM_FS_READ)
60 #define LOCKF_ENABLED_HARDIRQ_READ (1 << LOCK_ENABLED_HARDIRQ_READ)
61 #define LOCKF_ENABLED_SOFTIRQ_READ (1 << LOCK_ENABLED_SOFTIRQ_READ)
62 #define LOCKF_ENABLED_RECLAIM_FS_READ (1 << LOCK_ENABLED_RECLAIM_FS_READ)
64 #define LOCKF_ENABLED_IRQ_READ \
65 (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
66 #define LOCKF_USED_IN_IRQ_READ \
67 (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
69 #define MAX_LOCKDEP_SUBCLASSES 8UL
72 * Lock-classes are keyed via unique addresses, by embedding the
73 * lockclass-key into the kernel (or module) .data section. (For
74 * static locks we use the lock address itself as the key.)
76 struct lockdep_subclass_key {
78 } __attribute__ ((__packed__));
80 struct lock_class_key {
81 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
84 #define LOCKSTAT_POINTS 4
87 * The lock-class itself:
93 struct list_head hash_entry;
96 * global list of all lock-classes:
98 struct list_head lock_entry;
100 struct lockdep_subclass_key *key;
101 unsigned int subclass;
102 unsigned int dep_gen_id;
105 * IRQ/softirq usage tracking bits:
107 unsigned long usage_mask;
108 struct stack_trace usage_traces[LOCK_USAGE_STATES];
111 * These fields represent a directed graph of lock dependencies,
112 * to every node we attach a list of "forward" and a list of
113 * "backward" graph nodes.
115 struct list_head locks_after, locks_before;
118 * Generation counter, when doing certain classes of graph walking,
119 * to ensure that we check one node only once:
121 unsigned int version;
124 * Statistics counter:
131 #ifdef CONFIG_LOCK_STAT
132 unsigned long contention_point[LOCKSTAT_POINTS];
133 unsigned long contending_point[LOCKSTAT_POINTS];
137 #ifdef CONFIG_LOCK_STAT
146 bounce_acquired_write,
147 bounce_acquired_read,
148 bounce_contended_write,
149 bounce_contended_read,
152 bounce_acquired = bounce_acquired_write,
153 bounce_contended = bounce_contended_write,
156 struct lock_class_stats {
157 unsigned long contention_point[4];
158 unsigned long contending_point[4];
159 struct lock_time read_waittime;
160 struct lock_time write_waittime;
161 struct lock_time read_holdtime;
162 struct lock_time write_holdtime;
163 unsigned long bounces[nr_bounce_types];
166 struct lock_class_stats lock_stats(struct lock_class *class);
167 void clear_lock_stats(struct lock_class *class);
171 * Map the lock object (the lock instance) to the lock-class object.
172 * This is embedded into specific lock instances:
175 struct lock_class_key *key;
176 struct lock_class *class_cache;
178 #ifdef CONFIG_LOCK_STAT
185 * Every lock has a list of other locks that were taken after it.
186 * We only grow the list, never remove from it:
189 struct list_head entry;
190 struct lock_class *class;
191 struct stack_trace trace;
196 * We record lock dependency chains, so that we can cache them:
202 struct list_head entry;
206 #define MAX_LOCKDEP_KEYS_BITS 13
208 * Subtract one because we offset hlock->class_idx by 1 in order
209 * to make 0 mean no class. This avoids overflowing the class_idx
210 * bitfield and hitting the BUG in hlock_class().
212 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
216 * One-way hash of the dependency chain up to this point. We
217 * hash the hashes step by step as the dependency chain grows.
219 * We use it for dependency-caching and we skip detection
220 * passes and dependency-updates if there is a cache-hit, so
221 * it is absolutely critical for 100% coverage of the validator
222 * to have a unique key value for every unique dependency path
223 * that can occur in the system, to make a unique hash value
224 * as likely as possible - hence the 64-bit width.
226 * The task struct holds the current hash value (initialized
227 * with zero), here we store the previous hash value:
230 unsigned long acquire_ip;
231 struct lockdep_map *instance;
232 struct lockdep_map *nest_lock;
233 #ifdef CONFIG_LOCK_STAT
237 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
239 * The lock-stack is unified in that the lock chains of interrupt
240 * contexts nest ontop of process context chains, but we 'separate'
241 * the hashes by starting with 0 if we cross into an interrupt
242 * context, and we also keep do not add cross-context lock
243 * dependencies - the lock usage graph walking covers that area
244 * anyway, and we'd just unnecessarily increase the number of
245 * dependencies otherwise. [Note: hardirq and softirq contexts
246 * are separated from each other too.]
248 * The following field is used to detect when we cross into an
251 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
252 unsigned int trylock:1;
253 unsigned int read:2; /* see lock_acquire() comment */
254 unsigned int check:2; /* see lock_acquire() comment */
255 unsigned int hardirqs_off:1;
259 * Initialization, self-test and debugging-output methods:
261 extern void lockdep_init(void);
262 extern void lockdep_info(void);
263 extern void lockdep_reset(void);
264 extern void lockdep_reset_lock(struct lockdep_map *lock);
265 extern void lockdep_free_key_range(void *start, unsigned long size);
266 extern void lockdep_sys_exit(void);
268 extern void lockdep_off(void);
269 extern void lockdep_on(void);
272 * These methods are used by specific locking variants (spinlocks,
273 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
277 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
278 struct lock_class_key *key, int subclass);
281 * To initialize a lockdep_map statically use this macro.
282 * Note that _name must not be NULL.
284 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
285 { .name = (_name), .key = (void *)(_key), }
288 * Reinitialize a lock key - for cases where there is special locking or
289 * special initialization of locks so that the validator gets the scope
290 * of dependencies wrong: they are either too broad (they need a class-split)
291 * or they are too narrow (they suffer from a false class-split):
293 #define lockdep_set_class(lock, key) \
294 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
295 #define lockdep_set_class_and_name(lock, key, name) \
296 lockdep_init_map(&(lock)->dep_map, name, key, 0)
297 #define lockdep_set_class_and_subclass(lock, key, sub) \
298 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
299 #define lockdep_set_subclass(lock, sub) \
300 lockdep_init_map(&(lock)->dep_map, #lock, \
301 (lock)->dep_map.key, sub)
308 * 0: exclusive (write) acquire
309 * 1: read-acquire (no recursion allowed)
310 * 2: read-acquire with same-instance recursion allowed
315 * 1: simple checks (freeing, held-at-exit-time, etc.)
318 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
319 int trylock, int read, int check,
320 struct lockdep_map *nest_lock, unsigned long ip);
322 extern void lock_release(struct lockdep_map *lock, int nested,
325 extern void lock_set_class(struct lockdep_map *lock, const char *name,
326 struct lock_class_key *key, unsigned int subclass,
329 static inline void lock_set_subclass(struct lockdep_map *lock,
330 unsigned int subclass, unsigned long ip)
332 lock_set_class(lock, lock->name, lock->key, subclass, ip);
335 extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
336 extern void lockdep_clear_current_reclaim_state(void);
337 extern void lockdep_trace_alloc(gfp_t mask);
339 # define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
341 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
345 static inline void lockdep_off(void)
349 static inline void lockdep_on(void)
353 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
354 # define lock_release(l, n, i) do { } while (0)
355 # define lock_set_class(l, n, k, s, i) do { } while (0)
356 # define lock_set_subclass(l, s, i) do { } while (0)
357 # define lockdep_set_current_reclaim_state(g) do { } while (0)
358 # define lockdep_clear_current_reclaim_state() do { } while (0)
359 # define lockdep_trace_alloc(g) do { } while (0)
360 # define lockdep_init() do { } while (0)
361 # define lockdep_info() do { } while (0)
362 # define lockdep_init_map(lock, name, key, sub) \
363 do { (void)(name); (void)(key); } while (0)
364 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
365 # define lockdep_set_class_and_name(lock, key, name) \
366 do { (void)(key); (void)(name); } while (0)
367 #define lockdep_set_class_and_subclass(lock, key, sub) \
368 do { (void)(key); } while (0)
369 #define lockdep_set_subclass(lock, sub) do { } while (0)
371 # define INIT_LOCKDEP
372 # define lockdep_reset() do { debug_locks = 1; } while (0)
373 # define lockdep_free_key_range(start, size) do { } while (0)
374 # define lockdep_sys_exit() do { } while (0)
376 * The class key takes no space if lockdep is disabled:
378 struct lock_class_key { };
380 #define lockdep_depth(tsk) (0)
382 #endif /* !LOCKDEP */
384 #ifdef CONFIG_LOCK_STAT
386 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
387 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
389 #define LOCK_CONTENDED(_lock, try, lock) \
392 lock_contended(&(_lock)->dep_map, _RET_IP_); \
395 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
398 #else /* CONFIG_LOCK_STAT */
400 #define lock_contended(lockdep_map, ip) do {} while (0)
401 #define lock_acquired(lockdep_map, ip) do {} while (0)
403 #define LOCK_CONTENDED(_lock, try, lock) \
406 #endif /* CONFIG_LOCK_STAT */
408 #ifdef CONFIG_GENERIC_HARDIRQS
409 extern void early_init_irq_lock_class(void);
411 static inline void early_init_irq_lock_class(void)
416 #ifdef CONFIG_TRACE_IRQFLAGS
417 extern void early_boot_irqs_off(void);
418 extern void early_boot_irqs_on(void);
419 extern void print_irqtrace_events(struct task_struct *curr);
421 static inline void early_boot_irqs_off(void)
424 static inline void early_boot_irqs_on(void)
427 static inline void print_irqtrace_events(struct task_struct *curr)
433 * For trivial one-depth nesting of a lock-class, the following
434 * global define can be used. (Subsystems with multiple levels
435 * of nesting should define their own lock-nesting subclasses.)
437 #define SINGLE_DEPTH_NESTING 1
440 * Map the dependency ops to NOP or to real lockdep ops, depending
441 * on the per lock-class debug mode:
444 #ifdef CONFIG_DEBUG_LOCK_ALLOC
445 # ifdef CONFIG_PROVE_LOCKING
446 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
447 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i)
449 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
450 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i)
452 # define spin_release(l, n, i) lock_release(l, n, i)
454 # define spin_acquire(l, s, t, i) do { } while (0)
455 # define spin_release(l, n, i) do { } while (0)
458 #ifdef CONFIG_DEBUG_LOCK_ALLOC
459 # ifdef CONFIG_PROVE_LOCKING
460 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
461 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i)
463 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
464 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i)
466 # define rwlock_release(l, n, i) lock_release(l, n, i)
468 # define rwlock_acquire(l, s, t, i) do { } while (0)
469 # define rwlock_acquire_read(l, s, t, i) do { } while (0)
470 # define rwlock_release(l, n, i) do { } while (0)
473 #ifdef CONFIG_DEBUG_LOCK_ALLOC
474 # ifdef CONFIG_PROVE_LOCKING
475 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
477 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
479 # define mutex_release(l, n, i) lock_release(l, n, i)
481 # define mutex_acquire(l, s, t, i) do { } while (0)
482 # define mutex_release(l, n, i) do { } while (0)
485 #ifdef CONFIG_DEBUG_LOCK_ALLOC
486 # ifdef CONFIG_PROVE_LOCKING
487 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
488 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i)
490 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
491 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i)
493 # define rwsem_release(l, n, i) lock_release(l, n, i)
495 # define rwsem_acquire(l, s, t, i) do { } while (0)
496 # define rwsem_acquire_read(l, s, t, i) do { } while (0)
497 # define rwsem_release(l, n, i) do { } while (0)
500 #ifdef CONFIG_DEBUG_LOCK_ALLOC
501 # ifdef CONFIG_PROVE_LOCKING
502 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
504 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
506 # define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
508 # define lock_map_acquire(l) do { } while (0)
509 # define lock_map_release(l) do { } while (0)
512 #ifdef CONFIG_PROVE_LOCKING
513 # define might_lock(lock) \
515 typecheck(struct lockdep_map *, &(lock)->dep_map); \
516 lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
517 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
519 # define might_lock_read(lock) \
521 typecheck(struct lockdep_map *, &(lock)->dep_map); \
522 lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
523 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
526 # define might_lock(lock) do { } while (0)
527 # define might_lock_read(lock) do { } while (0)
530 #endif /* __LINUX_LOCKDEP_H */