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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Runtime locking correctness validator
4 *
5 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
7 *
8 * see Documentation/locking/lockdep-design.rst for more details.
9 */
10#ifndef __LINUX_LOCKDEP_H
11#define __LINUX_LOCKDEP_H
12
13#include <linux/lockdep_types.h>
14#include <linux/smp.h>
15#include <asm/percpu.h>
16
17struct task_struct;
18
19#ifdef CONFIG_LOCKDEP
20
21#include <linux/linkage.h>
22#include <linux/list.h>
23#include <linux/debug_locks.h>
24#include <linux/stacktrace.h>
25
26static inline void lockdep_copy_map(struct lockdep_map *to,
27 struct lockdep_map *from)
28{
29 int i;
30
31 *to = *from;
32 /*
33 * Since the class cache can be modified concurrently we could observe
34 * half pointers (64bit arch using 32bit copy insns). Therefore clear
35 * the caches and take the performance hit.
36 *
37 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
38 * that relies on cache abuse.
39 */
40 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
41 to->class_cache[i] = NULL;
42}
43
44/*
45 * Every lock has a list of other locks that were taken after it.
46 * We only grow the list, never remove from it:
47 */
48struct lock_list {
49 struct list_head entry;
50 struct lock_class *class;
51 struct lock_class *links_to;
52 const struct lock_trace *trace;
53 u16 distance;
54 /* bitmap of different dependencies from head to this */
55 u8 dep;
56 /* used by BFS to record whether "prev -> this" only has -(*R)-> */
57 u8 only_xr;
58
59 /*
60 * The parent field is used to implement breadth-first search, and the
61 * bit 0 is reused to indicate if the lock has been accessed in BFS.
62 */
63 struct lock_list *parent;
64};
65
66/**
67 * struct lock_chain - lock dependency chain record
68 *
69 * @irq_context: the same as irq_context in held_lock below
70 * @depth: the number of held locks in this chain
71 * @base: the index in chain_hlocks for this chain
72 * @entry: the collided lock chains in lock_chain hash list
73 * @chain_key: the hash key of this lock_chain
74 */
75struct lock_chain {
76 /* see BUILD_BUG_ON()s in add_chain_cache() */
77 unsigned int irq_context : 2,
78 depth : 6,
79 base : 24;
80 /* 4 byte hole */
81 struct hlist_node entry;
82 u64 chain_key;
83};
84
85/*
86 * Initialization, self-test and debugging-output methods:
87 */
88extern void lockdep_init(void);
89extern void lockdep_reset(void);
90extern void lockdep_reset_lock(struct lockdep_map *lock);
91extern void lockdep_free_key_range(void *start, unsigned long size);
92extern asmlinkage void lockdep_sys_exit(void);
93extern void lockdep_set_selftest_task(struct task_struct *task);
94
95extern void lockdep_init_task(struct task_struct *task);
96
97/*
98 * Split the recursion counter in two to readily detect 'off' vs recursion.
99 */
100#define LOCKDEP_RECURSION_BITS 16
101#define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS)
102#define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1)
103
104/*
105 * lockdep_{off,on}() are macros to avoid tracing and kprobes; not inlines due
106 * to header dependencies.
107 */
108
109#define lockdep_off() \
110do { \
111 current->lockdep_recursion += LOCKDEP_OFF; \
112} while (0)
113
114#define lockdep_on() \
115do { \
116 current->lockdep_recursion -= LOCKDEP_OFF; \
117} while (0)
118
119extern void lockdep_register_key(struct lock_class_key *key);
120extern void lockdep_unregister_key(struct lock_class_key *key);
121
122/*
123 * These methods are used by specific locking variants (spinlocks,
124 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
125 * to lockdep:
126 */
127
128extern void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
129 struct lock_class_key *key, int subclass, u8 inner, u8 outer, u8 lock_type);
130
131static inline void
132lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
133 struct lock_class_key *key, int subclass, u8 inner, u8 outer)
134{
135 lockdep_init_map_type(lock, name, key, subclass, inner, outer, lock_type: LD_LOCK_NORMAL);
136}
137
138static inline void
139lockdep_init_map_wait(struct lockdep_map *lock, const char *name,
140 struct lock_class_key *key, int subclass, u8 inner)
141{
142 lockdep_init_map_waits(lock, name, key, subclass, inner, outer: LD_WAIT_INV);
143}
144
145static inline void lockdep_init_map(struct lockdep_map *lock, const char *name,
146 struct lock_class_key *key, int subclass)
147{
148 lockdep_init_map_wait(lock, name, key, subclass, inner: LD_WAIT_INV);
149}
150
151/*
152 * Reinitialize a lock key - for cases where there is special locking or
153 * special initialization of locks so that the validator gets the scope
154 * of dependencies wrong: they are either too broad (they need a class-split)
155 * or they are too narrow (they suffer from a false class-split):
156 */
157#define lockdep_set_class(lock, key) \
158 lockdep_init_map_type(&(lock)->dep_map, #key, key, 0, \
159 (lock)->dep_map.wait_type_inner, \
160 (lock)->dep_map.wait_type_outer, \
161 (lock)->dep_map.lock_type)
162
163#define lockdep_set_class_and_name(lock, key, name) \
164 lockdep_init_map_type(&(lock)->dep_map, name, key, 0, \
165 (lock)->dep_map.wait_type_inner, \
166 (lock)->dep_map.wait_type_outer, \
167 (lock)->dep_map.lock_type)
168
169#define lockdep_set_class_and_subclass(lock, key, sub) \
170 lockdep_init_map_type(&(lock)->dep_map, #key, key, sub, \
171 (lock)->dep_map.wait_type_inner, \
172 (lock)->dep_map.wait_type_outer, \
173 (lock)->dep_map.lock_type)
174
175#define lockdep_set_subclass(lock, sub) \
176 lockdep_init_map_type(&(lock)->dep_map, (lock)->dep_map.name, (lock)->dep_map.key, sub,\
177 (lock)->dep_map.wait_type_inner, \
178 (lock)->dep_map.wait_type_outer, \
179 (lock)->dep_map.lock_type)
180
181/**
182 * lockdep_set_novalidate_class: disable checking of lock ordering on a given
183 * lock
184 * @lock: Lock to mark
185 *
186 * Lockdep will still record that this lock has been taken, and print held
187 * instances when dumping locks
188 */
189#define lockdep_set_novalidate_class(lock) \
190 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
191
192/**
193 * lockdep_set_notrack_class: disable lockdep tracking of a given lock entirely
194 * @lock: Lock to mark
195 *
196 * Bigger hammer than lockdep_set_novalidate_class: so far just for bcachefs,
197 * which takes more locks than lockdep is able to track (48).
198 */
199#define lockdep_set_notrack_class(lock) \
200 lockdep_set_class_and_name(lock, &__lockdep_no_track__, #lock)
201
202/*
203 * Compare locking classes
204 */
205#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
206
207static inline int lockdep_match_key(struct lockdep_map *lock,
208 struct lock_class_key *key)
209{
210 return lock->key == key;
211}
212
213/*
214 * Acquire a lock.
215 *
216 * Values for "read":
217 *
218 * 0: exclusive (write) acquire
219 * 1: read-acquire (no recursion allowed)
220 * 2: read-acquire with same-instance recursion allowed
221 *
222 * Values for check:
223 *
224 * 0: simple checks (freeing, held-at-exit-time, etc.)
225 * 1: full validation
226 */
227extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
228 int trylock, int read, int check,
229 struct lockdep_map *nest_lock, unsigned long ip);
230
231extern void lock_release(struct lockdep_map *lock, unsigned long ip);
232
233extern void lock_sync(struct lockdep_map *lock, unsigned int subclass,
234 int read, int check, struct lockdep_map *nest_lock,
235 unsigned long ip);
236
237/* lock_is_held_type() returns */
238#define LOCK_STATE_UNKNOWN -1
239#define LOCK_STATE_NOT_HELD 0
240#define LOCK_STATE_HELD 1
241
242/*
243 * Same "read" as for lock_acquire(), except -1 means any.
244 */
245extern int lock_is_held_type(const struct lockdep_map *lock, int read);
246
247static inline int lock_is_held(const struct lockdep_map *lock)
248{
249 return lock_is_held_type(lock, read: -1);
250}
251
252#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
253#define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
254
255extern void lock_set_class(struct lockdep_map *lock, const char *name,
256 struct lock_class_key *key, unsigned int subclass,
257 unsigned long ip);
258
259#define lock_set_novalidate_class(l, n, i) \
260 lock_set_class(l, n, &__lockdep_no_validate__, 0, i)
261
262static inline void lock_set_subclass(struct lockdep_map *lock,
263 unsigned int subclass, unsigned long ip)
264{
265 lock_set_class(lock, name: lock->name, key: lock->key, subclass, ip);
266}
267
268extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
269
270#define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
271
272extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
273extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
274extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
275
276#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
277
278#define lockdep_assert(cond) \
279 do { WARN_ON(debug_locks && !(cond)); } while (0)
280
281#define lockdep_assert_once(cond) \
282 do { WARN_ON_ONCE(debug_locks && !(cond)); } while (0)
283
284#define lockdep_assert_held(l) \
285 lockdep_assert(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)
286
287#define lockdep_assert_not_held(l) \
288 lockdep_assert(lockdep_is_held(l) != LOCK_STATE_HELD)
289
290#define lockdep_assert_held_write(l) \
291 lockdep_assert(lockdep_is_held_type(l, 0))
292
293#define lockdep_assert_held_read(l) \
294 lockdep_assert(lockdep_is_held_type(l, 1))
295
296#define lockdep_assert_held_once(l) \
297 lockdep_assert_once(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)
298
299#define lockdep_assert_none_held_once() \
300 lockdep_assert_once(!current->lockdep_depth)
301
302#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
303
304#define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
305#define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
306#define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
307
308/*
309 * Must use lock_map_aquire_try() with override maps to avoid
310 * lockdep thinking they participate in the block chain.
311 */
312#define DEFINE_WAIT_OVERRIDE_MAP(_name, _wait_type) \
313 struct lockdep_map _name = { \
314 .name = #_name "-wait-type-override", \
315 .wait_type_inner = _wait_type, \
316 .lock_type = LD_LOCK_WAIT_OVERRIDE, }
317
318#else /* !CONFIG_LOCKDEP */
319
320static inline void lockdep_init_task(struct task_struct *task)
321{
322}
323
324static inline void lockdep_off(void)
325{
326}
327
328static inline void lockdep_on(void)
329{
330}
331
332static inline void lockdep_set_selftest_task(struct task_struct *task)
333{
334}
335
336# define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
337# define lock_release(l, i) do { } while (0)
338# define lock_downgrade(l, i) do { } while (0)
339# define lock_set_class(l, n, key, s, i) do { (void)(key); } while (0)
340# define lock_set_novalidate_class(l, n, i) do { } while (0)
341# define lock_set_subclass(l, s, i) do { } while (0)
342# define lockdep_init() do { } while (0)
343# define lockdep_init_map_type(lock, name, key, sub, inner, outer, type) \
344 do { (void)(name); (void)(key); } while (0)
345# define lockdep_init_map_waits(lock, name, key, sub, inner, outer) \
346 do { (void)(name); (void)(key); } while (0)
347# define lockdep_init_map_wait(lock, name, key, sub, inner) \
348 do { (void)(name); (void)(key); } while (0)
349# define lockdep_init_map(lock, name, key, sub) \
350 do { (void)(name); (void)(key); } while (0)
351# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
352# define lockdep_set_class_and_name(lock, key, name) \
353 do { (void)(key); (void)(name); } while (0)
354#define lockdep_set_class_and_subclass(lock, key, sub) \
355 do { (void)(key); } while (0)
356#define lockdep_set_subclass(lock, sub) do { } while (0)
357
358#define lockdep_set_novalidate_class(lock) do { } while (0)
359#define lockdep_set_notrack_class(lock) do { } while (0)
360
361/*
362 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
363 * case since the result is not well defined and the caller should rather
364 * #ifdef the call himself.
365 */
366
367# define lockdep_reset() do { debug_locks = 1; } while (0)
368# define lockdep_free_key_range(start, size) do { } while (0)
369# define lockdep_sys_exit() do { } while (0)
370
371static inline void lockdep_register_key(struct lock_class_key *key)
372{
373}
374
375static inline void lockdep_unregister_key(struct lock_class_key *key)
376{
377}
378
379#define lockdep_depth(tsk) (0)
380
381/*
382 * Dummy forward declarations, allow users to write less ifdef-y code
383 * and depend on dead code elimination.
384 */
385extern int lock_is_held(const void *);
386extern int lockdep_is_held(const void *);
387#define lockdep_is_held_type(l, r) (1)
388
389#define lockdep_assert(c) do { } while (0)
390#define lockdep_assert_once(c) do { } while (0)
391
392#define lockdep_assert_held(l) do { (void)(l); } while (0)
393#define lockdep_assert_not_held(l) do { (void)(l); } while (0)
394#define lockdep_assert_held_write(l) do { (void)(l); } while (0)
395#define lockdep_assert_held_read(l) do { (void)(l); } while (0)
396#define lockdep_assert_held_once(l) do { (void)(l); } while (0)
397#define lockdep_assert_none_held_once() do { } while (0)
398
399#define lockdep_recursing(tsk) (0)
400
401#define NIL_COOKIE (struct pin_cookie){ }
402
403#define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; })
404#define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
405#define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
406
407#define DEFINE_WAIT_OVERRIDE_MAP(_name, _wait_type) \
408 struct lockdep_map __maybe_unused _name = {}
409
410#endif /* !LOCKDEP */
411
412#ifdef CONFIG_PROVE_LOCKING
413void lockdep_set_lock_cmp_fn(struct lockdep_map *, lock_cmp_fn, lock_print_fn);
414
415#define lock_set_cmp_fn(lock, ...) lockdep_set_lock_cmp_fn(&(lock)->dep_map, __VA_ARGS__)
416#else
417#define lock_set_cmp_fn(lock, ...) do { } while (0)
418#endif
419
420enum xhlock_context_t {
421 XHLOCK_HARD,
422 XHLOCK_SOFT,
423 XHLOCK_CTX_NR,
424};
425
426/*
427 * To initialize a lockdep_map statically use this macro.
428 * Note that _name must not be NULL.
429 */
430#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
431 { .name = (_name), .key = (void *)(_key), }
432
433static inline void lockdep_invariant_state(bool force) {}
434static inline void lockdep_free_task(struct task_struct *task) {}
435
436#ifdef CONFIG_LOCK_STAT
437
438extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
439extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
440
441#define LOCK_CONTENDED(_lock, try, lock) \
442do { \
443 if (!try(_lock)) { \
444 lock_contended(&(_lock)->dep_map, _RET_IP_); \
445 lock(_lock); \
446 } \
447 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
448} while (0)
449
450#define LOCK_CONTENDED_RETURN(_lock, try, lock) \
451({ \
452 int ____err = 0; \
453 if (!try(_lock)) { \
454 lock_contended(&(_lock)->dep_map, _RET_IP_); \
455 ____err = lock(_lock); \
456 } \
457 if (!____err) \
458 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
459 ____err; \
460})
461
462#else /* CONFIG_LOCK_STAT */
463
464#define lock_contended(lockdep_map, ip) do {} while (0)
465#define lock_acquired(lockdep_map, ip) do {} while (0)
466
467#define LOCK_CONTENDED(_lock, try, lock) \
468 lock(_lock)
469
470#define LOCK_CONTENDED_RETURN(_lock, try, lock) \
471 lock(_lock)
472
473#endif /* CONFIG_LOCK_STAT */
474
475#ifdef CONFIG_PROVE_LOCKING
476extern void print_irqtrace_events(struct task_struct *curr);
477#else
478static inline void print_irqtrace_events(struct task_struct *curr)
479{
480}
481#endif
482
483/* Variable used to make lockdep treat read_lock() as recursive in selftests */
484#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
485extern unsigned int force_read_lock_recursive;
486#else /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
487#define force_read_lock_recursive 0
488#endif /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
489
490#ifdef CONFIG_LOCKDEP
491extern bool read_lock_is_recursive(void);
492#else /* CONFIG_LOCKDEP */
493/* If !LOCKDEP, the value is meaningless */
494#define read_lock_is_recursive() 0
495#endif
496
497/*
498 * For trivial one-depth nesting of a lock-class, the following
499 * global define can be used. (Subsystems with multiple levels
500 * of nesting should define their own lock-nesting subclasses.)
501 */
502#define SINGLE_DEPTH_NESTING 1
503
504/*
505 * Map the dependency ops to NOP or to real lockdep ops, depending
506 * on the per lock-class debug mode:
507 */
508
509#define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
510#define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
511#define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
512
513#define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
514#define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
515#define spin_release(l, i) lock_release(l, i)
516
517#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
518#define rwlock_acquire_read(l, s, t, i) \
519do { \
520 if (read_lock_is_recursive()) \
521 lock_acquire_shared_recursive(l, s, t, NULL, i); \
522 else \
523 lock_acquire_shared(l, s, t, NULL, i); \
524} while (0)
525
526#define rwlock_release(l, i) lock_release(l, i)
527
528#define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
529#define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
530#define seqcount_release(l, i) lock_release(l, i)
531
532#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
533#define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
534#define mutex_release(l, i) lock_release(l, i)
535
536#define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
537#define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
538#define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
539#define rwsem_release(l, i) lock_release(l, i)
540
541#define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
542#define lock_map_acquire_try(l) lock_acquire_exclusive(l, 0, 1, NULL, _THIS_IP_)
543#define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
544#define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
545#define lock_map_release(l) lock_release(l, _THIS_IP_)
546#define lock_map_sync(l) lock_sync(l, 0, 0, 1, NULL, _THIS_IP_)
547
548#ifdef CONFIG_PROVE_LOCKING
549# define might_lock(lock) \
550do { \
551 typecheck(struct lockdep_map *, &(lock)->dep_map); \
552 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
553 lock_release(&(lock)->dep_map, _THIS_IP_); \
554} while (0)
555# define might_lock_read(lock) \
556do { \
557 typecheck(struct lockdep_map *, &(lock)->dep_map); \
558 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
559 lock_release(&(lock)->dep_map, _THIS_IP_); \
560} while (0)
561# define might_lock_nested(lock, subclass) \
562do { \
563 typecheck(struct lockdep_map *, &(lock)->dep_map); \
564 lock_acquire(&(lock)->dep_map, subclass, 0, 1, 1, NULL, \
565 _THIS_IP_); \
566 lock_release(&(lock)->dep_map, _THIS_IP_); \
567} while (0)
568
569DECLARE_PER_CPU(int, hardirqs_enabled);
570DECLARE_PER_CPU(int, hardirq_context);
571DECLARE_PER_CPU(unsigned int, lockdep_recursion);
572
573#define __lockdep_enabled (debug_locks && !this_cpu_read(lockdep_recursion))
574
575#define lockdep_assert_irqs_enabled() \
576do { \
577 WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirqs_enabled)); \
578} while (0)
579
580#define lockdep_assert_irqs_disabled() \
581do { \
582 WARN_ON_ONCE(__lockdep_enabled && this_cpu_read(hardirqs_enabled)); \
583} while (0)
584
585#define lockdep_assert_in_irq() \
586do { \
587 WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirq_context)); \
588} while (0)
589
590#define lockdep_assert_no_hardirq() \
591do { \
592 WARN_ON_ONCE(__lockdep_enabled && (this_cpu_read(hardirq_context) || \
593 !this_cpu_read(hardirqs_enabled))); \
594} while (0)
595
596#define lockdep_assert_preemption_enabled() \
597do { \
598 WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT) && \
599 __lockdep_enabled && \
600 (preempt_count() != 0 || \
601 !this_cpu_read(hardirqs_enabled))); \
602} while (0)
603
604#define lockdep_assert_preemption_disabled() \
605do { \
606 WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT) && \
607 __lockdep_enabled && \
608 (preempt_count() == 0 && \
609 this_cpu_read(hardirqs_enabled))); \
610} while (0)
611
612/*
613 * Acceptable for protecting per-CPU resources accessed from BH.
614 * Much like in_softirq() - semantics are ambiguous, use carefully.
615 */
616#define lockdep_assert_in_softirq() \
617do { \
618 WARN_ON_ONCE(__lockdep_enabled && \
619 (!in_softirq() || in_hardirq() || in_nmi())); \
620} while (0)
621
622extern void lockdep_assert_in_softirq_func(void);
623
624#else
625# define might_lock(lock) do { } while (0)
626# define might_lock_read(lock) do { } while (0)
627# define might_lock_nested(lock, subclass) do { } while (0)
628
629# define lockdep_assert_irqs_enabled() do { } while (0)
630# define lockdep_assert_irqs_disabled() do { } while (0)
631# define lockdep_assert_in_irq() do { } while (0)
632# define lockdep_assert_no_hardirq() do { } while (0)
633
634# define lockdep_assert_preemption_enabled() do { } while (0)
635# define lockdep_assert_preemption_disabled() do { } while (0)
636# define lockdep_assert_in_softirq() do { } while (0)
637# define lockdep_assert_in_softirq_func() do { } while (0)
638#endif
639
640#ifdef CONFIG_PROVE_RAW_LOCK_NESTING
641
642# define lockdep_assert_RT_in_threaded_ctx() do { \
643 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
644 lockdep_hardirq_context() && \
645 !(current->hardirq_threaded || current->irq_config), \
646 "Not in threaded context on PREEMPT_RT as expected\n"); \
647} while (0)
648
649#else
650
651# define lockdep_assert_RT_in_threaded_ctx() do { } while (0)
652
653#endif
654
655#ifdef CONFIG_LOCKDEP
656void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
657#else
658static inline void
659lockdep_rcu_suspicious(const char *file, const int line, const char *s)
660{
661}
662#endif
663
664#endif /* __LINUX_LOCKDEP_H */
665

source code of linux/include/linux/lockdep.h