1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Runtime locking correctness validator
5 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
8 * see Documentation/locking/lockdep-design.rst for more details.
10 #ifndef __LINUX_LOCKDEP_H
11 #define __LINUX_LOCKDEP_H
17 extern int prove_locking;
20 #define MAX_LOCKDEP_SUBCLASSES 8UL
22 #include <linux/types.h>
26 #include <linux/linkage.h>
27 #include <linux/list.h>
28 #include <linux/debug_locks.h>
29 #include <linux/stacktrace.h>
32 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
33 * the total number of states... :-(
35 #define XXX_LOCK_USAGE_STATES (1+2*4)
38 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
39 * cached in the instance of lockdep_map
41 * Currently main class (subclass == 0) and signle depth subclass
42 * are cached in lockdep_map. This optimization is mainly targeting
43 * on rq->lock. double_rq_lock() acquires this highly competitive with
46 #define NR_LOCKDEP_CACHING_CLASSES 2
49 * A lockdep key is associated with each lock object. For static locks we use
50 * the lock address itself as the key. Dynamically allocated lock objects can
51 * have a statically or dynamically allocated key. Dynamically allocated lock
52 * keys must be registered before being used and must be unregistered before
53 * the key memory is freed.
55 struct lockdep_subclass_key {
57 } __attribute__ ((__packed__));
59 /* hash_entry is used to keep track of dynamically allocated keys. */
60 struct lock_class_key {
62 struct hlist_node hash_entry;
63 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
67 extern struct lock_class_key __lockdep_no_validate__;
70 unsigned int nr_entries;
74 #define LOCKSTAT_POINTS 4
77 * The lock-class itself. The order of the structure members matters.
78 * reinit_class() zeroes the key member and all subsequent members.
84 struct hlist_node hash_entry;
87 * Entry in all_lock_classes when in use. Entry in free_lock_classes
88 * when not in use. Instances that are being freed are on one of the
89 * zapped_classes lists.
91 struct list_head lock_entry;
94 * These fields represent a directed graph of lock dependencies,
95 * to every node we attach a list of "forward" and a list of
96 * "backward" graph nodes.
98 struct list_head locks_after, locks_before;
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 lock_trace usage_traces[XXX_LOCK_USAGE_STATES];
111 * Generation counter, when doing certain classes of graph walking,
112 * to ensure that we check one node only once:
117 #ifdef CONFIG_LOCK_STAT
118 unsigned long contention_point[LOCKSTAT_POINTS];
119 unsigned long contending_point[LOCKSTAT_POINTS];
121 } __no_randomize_layout;
123 #ifdef CONFIG_LOCK_STAT
132 bounce_acquired_write,
133 bounce_acquired_read,
134 bounce_contended_write,
135 bounce_contended_read,
138 bounce_acquired = bounce_acquired_write,
139 bounce_contended = bounce_contended_write,
142 struct lock_class_stats {
143 unsigned long contention_point[LOCKSTAT_POINTS];
144 unsigned long contending_point[LOCKSTAT_POINTS];
145 struct lock_time read_waittime;
146 struct lock_time write_waittime;
147 struct lock_time read_holdtime;
148 struct lock_time write_holdtime;
149 unsigned long bounces[nr_bounce_types];
152 struct lock_class_stats lock_stats(struct lock_class *class);
153 void clear_lock_stats(struct lock_class *class);
157 * Map the lock object (the lock instance) to the lock-class object.
158 * This is embedded into specific lock instances:
161 struct lock_class_key *key;
162 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
164 #ifdef CONFIG_LOCK_STAT
170 static inline void lockdep_copy_map(struct lockdep_map *to,
171 struct lockdep_map *from)
177 * Since the class cache can be modified concurrently we could observe
178 * half pointers (64bit arch using 32bit copy insns). Therefore clear
179 * the caches and take the performance hit.
181 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
182 * that relies on cache abuse.
184 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
185 to->class_cache[i] = NULL;
189 * Every lock has a list of other locks that were taken after it.
190 * We only grow the list, never remove from it:
193 struct list_head entry;
194 struct lock_class *class;
195 struct lock_class *links_to;
196 struct lock_trace trace;
200 * The parent field is used to implement breadth-first search, and the
201 * bit 0 is reused to indicate if the lock has been accessed in BFS.
203 struct lock_list *parent;
207 * struct lock_chain - lock dependency chain record
209 * @irq_context: the same as irq_context in held_lock below
210 * @depth: the number of held locks in this chain
211 * @base: the index in chain_hlocks for this chain
212 * @entry: the collided lock chains in lock_chain hash list
213 * @chain_key: the hash key of this lock_chain
216 /* see BUILD_BUG_ON()s in add_chain_cache() */
217 unsigned int irq_context : 2,
221 struct hlist_node entry;
225 #define MAX_LOCKDEP_KEYS_BITS 13
226 #define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
227 #define INITIAL_CHAIN_KEY -1
231 * One-way hash of the dependency chain up to this point. We
232 * hash the hashes step by step as the dependency chain grows.
234 * We use it for dependency-caching and we skip detection
235 * passes and dependency-updates if there is a cache-hit, so
236 * it is absolutely critical for 100% coverage of the validator
237 * to have a unique key value for every unique dependency path
238 * that can occur in the system, to make a unique hash value
239 * as likely as possible - hence the 64-bit width.
241 * The task struct holds the current hash value (initialized
242 * with zero), here we store the previous hash value:
245 unsigned long acquire_ip;
246 struct lockdep_map *instance;
247 struct lockdep_map *nest_lock;
248 #ifdef CONFIG_LOCK_STAT
253 * class_idx is zero-indexed; it points to the element in
254 * lock_classes this held lock instance belongs to. class_idx is in
255 * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
257 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
259 * The lock-stack is unified in that the lock chains of interrupt
260 * contexts nest ontop of process context chains, but we 'separate'
261 * the hashes by starting with 0 if we cross into an interrupt
262 * context, and we also keep do not add cross-context lock
263 * dependencies - the lock usage graph walking covers that area
264 * anyway, and we'd just unnecessarily increase the number of
265 * dependencies otherwise. [Note: hardirq and softirq contexts
266 * are separated from each other too.]
268 * The following field is used to detect when we cross into an
271 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
272 unsigned int trylock:1; /* 16 bits */
274 unsigned int read:2; /* see lock_acquire() comment */
275 unsigned int check:1; /* see lock_acquire() comment */
276 unsigned int hardirqs_off:1;
277 unsigned int references:12; /* 32 bits */
278 unsigned int pin_count;
282 * Initialization, self-test and debugging-output methods:
284 extern void lockdep_init(void);
285 extern void lockdep_reset(void);
286 extern void lockdep_reset_lock(struct lockdep_map *lock);
287 extern void lockdep_free_key_range(void *start, unsigned long size);
288 extern asmlinkage void lockdep_sys_exit(void);
289 extern void lockdep_set_selftest_task(struct task_struct *task);
291 extern void lockdep_init_task(struct task_struct *task);
293 extern void lockdep_off(void);
294 extern void lockdep_on(void);
296 extern void lockdep_register_key(struct lock_class_key *key);
297 extern void lockdep_unregister_key(struct lock_class_key *key);
300 * These methods are used by specific locking variants (spinlocks,
301 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
305 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
306 struct lock_class_key *key, int subclass);
309 * Reinitialize a lock key - for cases where there is special locking or
310 * special initialization of locks so that the validator gets the scope
311 * of dependencies wrong: they are either too broad (they need a class-split)
312 * or they are too narrow (they suffer from a false class-split):
314 #define lockdep_set_class(lock, key) \
315 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
316 #define lockdep_set_class_and_name(lock, key, name) \
317 lockdep_init_map(&(lock)->dep_map, name, key, 0)
318 #define lockdep_set_class_and_subclass(lock, key, sub) \
319 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
320 #define lockdep_set_subclass(lock, sub) \
321 lockdep_init_map(&(lock)->dep_map, #lock, \
322 (lock)->dep_map.key, sub)
324 #define lockdep_set_novalidate_class(lock) \
325 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
327 * Compare locking classes
329 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
331 static inline int lockdep_match_key(struct lockdep_map *lock,
332 struct lock_class_key *key)
334 return lock->key == key;
342 * 0: exclusive (write) acquire
343 * 1: read-acquire (no recursion allowed)
344 * 2: read-acquire with same-instance recursion allowed
348 * 0: simple checks (freeing, held-at-exit-time, etc.)
351 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
352 int trylock, int read, int check,
353 struct lockdep_map *nest_lock, unsigned long ip);
355 extern void lock_release(struct lockdep_map *lock, int nested,
359 * Same "read" as for lock_acquire(), except -1 means any.
361 extern int lock_is_held_type(const struct lockdep_map *lock, int read);
363 static inline int lock_is_held(const struct lockdep_map *lock)
365 return lock_is_held_type(lock, -1);
368 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
369 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
371 extern void lock_set_class(struct lockdep_map *lock, const char *name,
372 struct lock_class_key *key, unsigned int subclass,
375 static inline void lock_set_subclass(struct lockdep_map *lock,
376 unsigned int subclass, unsigned long ip)
378 lock_set_class(lock, lock->name, lock->key, subclass, ip);
381 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
383 struct pin_cookie { unsigned int val; };
385 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
387 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
388 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
389 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
391 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
393 #define lockdep_assert_held(l) do { \
394 WARN_ON(debug_locks && !lockdep_is_held(l)); \
397 #define lockdep_assert_held_write(l) do { \
398 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
401 #define lockdep_assert_held_read(l) do { \
402 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
405 #define lockdep_assert_held_once(l) do { \
406 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
409 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
411 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
412 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
413 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
415 #else /* !CONFIG_LOCKDEP */
417 static inline void lockdep_init_task(struct task_struct *task)
421 static inline void lockdep_off(void)
425 static inline void lockdep_on(void)
429 static inline void lockdep_set_selftest_task(struct task_struct *task)
433 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
434 # define lock_release(l, n, i) do { } while (0)
435 # define lock_downgrade(l, i) do { } while (0)
436 # define lock_set_class(l, n, k, s, i) do { } while (0)
437 # define lock_set_subclass(l, s, i) do { } while (0)
438 # define lockdep_init() do { } while (0)
439 # define lockdep_init_map(lock, name, key, sub) \
440 do { (void)(name); (void)(key); } while (0)
441 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
442 # define lockdep_set_class_and_name(lock, key, name) \
443 do { (void)(key); (void)(name); } while (0)
444 #define lockdep_set_class_and_subclass(lock, key, sub) \
445 do { (void)(key); } while (0)
446 #define lockdep_set_subclass(lock, sub) do { } while (0)
448 #define lockdep_set_novalidate_class(lock) do { } while (0)
451 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
452 * case since the result is not well defined and the caller should rather
453 * #ifdef the call himself.
456 # define lockdep_reset() do { debug_locks = 1; } while (0)
457 # define lockdep_free_key_range(start, size) do { } while (0)
458 # define lockdep_sys_exit() do { } while (0)
460 * The class key takes no space if lockdep is disabled:
462 struct lock_class_key { };
464 static inline void lockdep_register_key(struct lock_class_key *key)
468 static inline void lockdep_unregister_key(struct lock_class_key *key)
473 * The lockdep_map takes no space if lockdep is disabled:
475 struct lockdep_map { };
477 #define lockdep_depth(tsk) (0)
479 #define lockdep_is_held_type(l, r) (1)
481 #define lockdep_assert_held(l) do { (void)(l); } while (0)
482 #define lockdep_assert_held_write(l) do { (void)(l); } while (0)
483 #define lockdep_assert_held_read(l) do { (void)(l); } while (0)
484 #define lockdep_assert_held_once(l) do { (void)(l); } while (0)
486 #define lockdep_recursing(tsk) (0)
488 struct pin_cookie { };
490 #define NIL_COOKIE (struct pin_cookie){ }
492 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; })
493 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
494 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
496 #endif /* !LOCKDEP */
498 enum xhlock_context_t {
504 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
506 * To initialize a lockdep_map statically use this macro.
507 * Note that _name must not be NULL.
509 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
510 { .name = (_name), .key = (void *)(_key), }
512 static inline void lockdep_invariant_state(bool force) {}
513 static inline void lockdep_free_task(struct task_struct *task) {}
515 #ifdef CONFIG_LOCK_STAT
517 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
518 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
520 #define LOCK_CONTENDED(_lock, try, lock) \
523 lock_contended(&(_lock)->dep_map, _RET_IP_); \
526 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
529 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
533 lock_contended(&(_lock)->dep_map, _RET_IP_); \
534 ____err = lock(_lock); \
537 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
541 #else /* CONFIG_LOCK_STAT */
543 #define lock_contended(lockdep_map, ip) do {} while (0)
544 #define lock_acquired(lockdep_map, ip) do {} while (0)
546 #define LOCK_CONTENDED(_lock, try, lock) \
549 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
552 #endif /* CONFIG_LOCK_STAT */
554 #ifdef CONFIG_LOCKDEP
557 * On lockdep we dont want the hand-coded irq-enable of
558 * _raw_*_lock_flags() code, because lockdep assumes
559 * that interrupts are not re-enabled during lock-acquire:
561 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
562 LOCK_CONTENDED((_lock), (try), (lock))
564 #else /* CONFIG_LOCKDEP */
566 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
567 lockfl((_lock), (flags))
569 #endif /* CONFIG_LOCKDEP */
571 #ifdef CONFIG_PROVE_LOCKING
572 extern void print_irqtrace_events(struct task_struct *curr);
574 static inline void print_irqtrace_events(struct task_struct *curr)
580 * For trivial one-depth nesting of a lock-class, the following
581 * global define can be used. (Subsystems with multiple levels
582 * of nesting should define their own lock-nesting subclasses.)
584 #define SINGLE_DEPTH_NESTING 1
587 * Map the dependency ops to NOP or to real lockdep ops, depending
588 * on the per lock-class debug mode:
591 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
592 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
593 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
595 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
596 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
597 #define spin_release(l, n, i) lock_release(l, n, i)
599 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
600 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
601 #define rwlock_release(l, n, i) lock_release(l, n, i)
603 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
604 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
605 #define seqcount_release(l, n, i) lock_release(l, n, i)
607 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
608 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
609 #define mutex_release(l, n, i) lock_release(l, n, i)
611 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
612 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
613 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
614 #define rwsem_release(l, n, i) lock_release(l, n, i)
616 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
617 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
618 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
619 #define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
621 #ifdef CONFIG_PROVE_LOCKING
622 # define might_lock(lock) \
624 typecheck(struct lockdep_map *, &(lock)->dep_map); \
625 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
626 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
628 # define might_lock_read(lock) \
630 typecheck(struct lockdep_map *, &(lock)->dep_map); \
631 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
632 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
635 #define lockdep_assert_irqs_enabled() do { \
636 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
637 !current->hardirqs_enabled, \
638 "IRQs not enabled as expected\n"); \
641 #define lockdep_assert_irqs_disabled() do { \
642 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
643 current->hardirqs_enabled, \
644 "IRQs not disabled as expected\n"); \
647 #define lockdep_assert_in_irq() do { \
648 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
649 !current->hardirq_context, \
650 "Not in hardirq as expected\n"); \
654 # define might_lock(lock) do { } while (0)
655 # define might_lock_read(lock) do { } while (0)
656 # define lockdep_assert_irqs_enabled() do { } while (0)
657 # define lockdep_assert_irqs_disabled() do { } while (0)
658 # define lockdep_assert_in_irq() do { } while (0)
661 #ifdef CONFIG_LOCKDEP
662 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
665 lockdep_rcu_suspicious(const char *file, const int line, const char *s)
670 #endif /* __LINUX_LOCKDEP_H */