include/linux/lockdep.h

   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.txt for more details.
   9  */
  10 #ifndef __LINUX_LOCKDEP_H
  11 #define __LINUX_LOCKDEP_H
  12
  13 struct task_struct;
  14 struct lockdep_map;
  15
  16 /* for sysctl */
  17 extern int prove_locking;
  18 extern int lock_stat;
  19
  20 #define MAX_LOCKDEP_SUBCLASSES          8UL
  21
  22 #include <linux/types.h>
  23
  24 #ifdef CONFIG_LOCKDEP
  25
  26 #include <linux/linkage.h>
  27 #include <linux/list.h>
  28 #include <linux/debug_locks.h>
  29 #include <linux/stacktrace.h>
  30
  31 /*
  32  * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
  33  * the total number of states... :-(
  34  */
  35 #define XXX_LOCK_USAGE_STATES           (1+2*4)
  36
  37 /*
  38  * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
  39  * cached in the instance of lockdep_map
  40  *
  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
  44  * single depth.
  45  */
  46 #define NR_LOCKDEP_CACHING_CLASSES      2
  47
  48 /*
  49  * Lock-classes are keyed via unique addresses, by embedding the
  50  * lockclass-key into the kernel (or module) .data section. (For
  51  * static locks we use the lock address itself as the key.)
  52  */
  53 struct lockdep_subclass_key {
  54         char __one_byte;
  55 } __attribute__ ((__packed__));
  56
  57 struct lock_class_key {
  58         struct lockdep_subclass_key     subkeys[MAX_LOCKDEP_SUBCLASSES];
  59 };
  60
  61 extern struct lock_class_key __lockdep_no_validate__;
  62
  63 #define LOCKSTAT_POINTS         4
  64
  65 /*
  66  * The lock-class itself:
  67  */
  68 struct lock_class {
  69         /*
  70          * class-hash:
  71          */
  72         struct hlist_node               hash_entry;
  73
  74         /*
  75          * global list of all lock-classes:
  76          */
  77         struct list_head                lock_entry;
  78
  79         struct lockdep_subclass_key     *key;
  80         unsigned int                    subclass;
  81         unsigned int                    dep_gen_id;
  82
  83         /*
  84          * IRQ/softirq usage tracking bits:
  85          */
  86         unsigned long                   usage_mask;
  87         struct stack_trace              usage_traces[XXX_LOCK_USAGE_STATES];
  88
  89         /*
  90          * These fields represent a directed graph of lock dependencies,
  91          * to every node we attach a list of "forward" and a list of
  92          * "backward" graph nodes.
  93          */
  94         struct list_head                locks_after, locks_before;
  95
  96         /*
  97          * Generation counter, when doing certain classes of graph walking,
  98          * to ensure that we check one node only once:
  99          */
 100         unsigned int                    version;
 101
 102         /*
 103          * Statistics counter:
 104          */
 105         unsigned long                   ops;
 106
 107         const char                      *name;
 108         int                             name_version;
 109
 110 #ifdef CONFIG_LOCK_STAT
 111         unsigned long                   contention_point[LOCKSTAT_POINTS];
 112         unsigned long                   contending_point[LOCKSTAT_POINTS];
 113 #endif
 114 };
 115
 116 #ifdef CONFIG_LOCK_STAT
 117 struct lock_time {
 118         s64                             min;
 119         s64                             max;
 120         s64                             total;
 121         unsigned long                   nr;
 122 };
 123
 124 enum bounce_type {
 125         bounce_acquired_write,
 126         bounce_acquired_read,
 127         bounce_contended_write,
 128         bounce_contended_read,
 129         nr_bounce_types,
 130
 131         bounce_acquired = bounce_acquired_write,
 132         bounce_contended = bounce_contended_write,
 133 };
 134
 135 struct lock_class_stats {
 136         unsigned long                   contention_point[LOCKSTAT_POINTS];
 137         unsigned long                   contending_point[LOCKSTAT_POINTS];
 138         struct lock_time                read_waittime;
 139         struct lock_time                write_waittime;
 140         struct lock_time                read_holdtime;
 141         struct lock_time                write_holdtime;
 142         unsigned long                   bounces[nr_bounce_types];
 143 };
 144
 145 struct lock_class_stats lock_stats(struct lock_class *class);
 146 void clear_lock_stats(struct lock_class *class);
 147 #endif
 148
 149 /*
 150  * Map the lock object (the lock instance) to the lock-class object.
 151  * This is embedded into specific lock instances:
 152  */
 153 struct lockdep_map {
 154         struct lock_class_key           *key;
 155         struct lock_class               *class_cache[NR_LOCKDEP_CACHING_CLASSES];
 156         const char                      *name;
 157 #ifdef CONFIG_LOCK_STAT
 158         int                             cpu;
 159         unsigned long                   ip;
 160 #endif
 161 };
 162
 163 static inline void lockdep_copy_map(struct lockdep_map *to,
 164                                     struct lockdep_map *from)
 165 {
 166         int i;
 167
 168         *to = *from;
 169         /*
 170          * Since the class cache can be modified concurrently we could observe
 171          * half pointers (64bit arch using 32bit copy insns). Therefore clear
 172          * the caches and take the performance hit.
 173          *
 174          * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
 175          *     that relies on cache abuse.
 176          */
 177         for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
 178                 to->class_cache[i] = NULL;
 179 }
 180
 181 /*
 182  * Every lock has a list of other locks that were taken after it.
 183  * We only grow the list, never remove from it:
 184  */
 185 struct lock_list {
 186         struct list_head                entry;
 187         struct lock_class               *class;
 188         struct stack_trace              trace;
 189         int                             distance;
 190
 191         /*
 192          * The parent field is used to implement breadth-first search, and the
 193          * bit 0 is reused to indicate if the lock has been accessed in BFS.
 194          */
 195         struct lock_list                *parent;
 196 };
 197
 198 /*
 199  * We record lock dependency chains, so that we can cache them:
 200  */
 201 struct lock_chain {
 202         /* see BUILD_BUG_ON()s in lookup_chain_cache() */
 203         unsigned int                    irq_context :  2,
 204                                         depth       :  6,
 205                                         base        : 24;
 206         /* 4 byte hole */
 207         struct hlist_node               entry;
 208         u64                             chain_key;
 209 };
 210
 211 #define MAX_LOCKDEP_KEYS_BITS           13
 212 /*
 213  * Subtract one because we offset hlock->class_idx by 1 in order
 214  * to make 0 mean no class. This avoids overflowing the class_idx
 215  * bitfield and hitting the BUG in hlock_class().
 216  */
 217 #define MAX_LOCKDEP_KEYS                ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
 218
 219 struct held_lock {
 220         /*
 221          * One-way hash of the dependency chain up to this point. We
 222          * hash the hashes step by step as the dependency chain grows.
 223          *
 224          * We use it for dependency-caching and we skip detection
 225          * passes and dependency-updates if there is a cache-hit, so
 226          * it is absolutely critical for 100% coverage of the validator
 227          * to have a unique key value for every unique dependency path
 228          * that can occur in the system, to make a unique hash value
 229          * as likely as possible - hence the 64-bit width.
 230          *
 231          * The task struct holds the current hash value (initialized
 232          * with zero), here we store the previous hash value:
 233          */
 234         u64                             prev_chain_key;
 235         unsigned long                   acquire_ip;
 236         struct lockdep_map              *instance;
 237         struct lockdep_map              *nest_lock;
 238 #ifdef CONFIG_LOCK_STAT
 239         u64                             waittime_stamp;
 240         u64                             holdtime_stamp;
 241 #endif
 242         unsigned int                    class_idx:MAX_LOCKDEP_KEYS_BITS;
 243         /*
 244          * The lock-stack is unified in that the lock chains of interrupt
 245          * contexts nest ontop of process context chains, but we 'separate'
 246          * the hashes by starting with 0 if we cross into an interrupt
 247          * context, and we also keep do not add cross-context lock
 248          * dependencies - the lock usage graph walking covers that area
 249          * anyway, and we'd just unnecessarily increase the number of
 250          * dependencies otherwise. [Note: hardirq and softirq contexts
 251          * are separated from each other too.]
 252          *
 253          * The following field is used to detect when we cross into an
 254          * interrupt context:
 255          */
 256         unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
 257         unsigned int trylock:1;                                         /* 16 bits */
 258
 259         unsigned int read:2;        /* see lock_acquire() comment */
 260         unsigned int check:1;       /* see lock_acquire() comment */
 261         unsigned int hardirqs_off:1;
 262         unsigned int references:12;                                     /* 32 bits */
 263         unsigned int pin_count;
 264 };
 265
 266 /*
 267  * Initialization, self-test and debugging-output methods:
 268  */
 269 extern void lockdep_info(void);
 270 extern void lockdep_reset(void);
 271 extern void lockdep_reset_lock(struct lockdep_map *lock);
 272 extern void lockdep_free_key_range(void *start, unsigned long size);
 273 extern asmlinkage void lockdep_sys_exit(void);
 274
 275 extern void lockdep_off(void);
 276 extern void lockdep_on(void);
 277
 278 /*
 279  * These methods are used by specific locking variants (spinlocks,
 280  * rwlocks, mutexes and rwsems) to pass init/acquire/release events
 281  * to lockdep:
 282  */
 283
 284 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
 285                              struct lock_class_key *key, int subclass);
 286
 287 /*
 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):
 292  */
 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)
 302
 303 #define lockdep_set_novalidate_class(lock) \
 304         lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
 305 /*
 306  * Compare locking classes
 307  */
 308 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
 309
 310 static inline int lockdep_match_key(struct lockdep_map *lock,
 311                                     struct lock_class_key *key)
 312 {
 313         return lock->key == key;
 314 }
 315
 316 /*
 317  * Acquire a lock.
 318  *
 319  * Values for "read":
 320  *
 321  *   0: exclusive (write) acquire
 322  *   1: read-acquire (no recursion allowed)
 323  *   2: read-acquire with same-instance recursion allowed
 324  *
 325  * Values for check:
 326  *
 327  *   0: simple checks (freeing, held-at-exit-time, etc.)
 328  *   1: full validation
 329  */
 330 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 331                          int trylock, int read, int check,
 332                          struct lockdep_map *nest_lock, unsigned long ip);
 333
 334 extern void lock_release(struct lockdep_map *lock, int nested,
 335                          unsigned long ip);
 336
 337 /*
 338  * Same "read" as for lock_acquire(), except -1 means any.
 339  */
 340 extern int lock_is_held_type(struct lockdep_map *lock, int read);
 341
 342 static inline int lock_is_held(struct lockdep_map *lock)
 343 {
 344         return lock_is_held_type(lock, -1);
 345 }
 346
 347 #define lockdep_is_held(lock)           lock_is_held(&(lock)->dep_map)
 348 #define lockdep_is_held_type(lock, r)   lock_is_held_type(&(lock)->dep_map, (r))
 349
 350 extern void lock_set_class(struct lockdep_map *lock, const char *name,
 351                            struct lock_class_key *key, unsigned int subclass,
 352                            unsigned long ip);
 353
 354 static inline void lock_set_subclass(struct lockdep_map *lock,
 355                 unsigned int subclass, unsigned long ip)
 356 {
 357         lock_set_class(lock, lock->name, lock->key, subclass, ip);
 358 }
 359
 360 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
 361
 362 struct pin_cookie { unsigned int val; };
 363
 364 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
 365
 366 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
 367 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
 368 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
 369
 370 # define INIT_LOCKDEP                           .lockdep_recursion = 0,
 371
 372 #define lockdep_depth(tsk)      (debug_locks ? (tsk)->lockdep_depth : 0)
 373
 374 #define lockdep_assert_held(l)  do {                            \
 375                 WARN_ON(debug_locks && !lockdep_is_held(l));    \
 376         } while (0)
 377
 378 #define lockdep_assert_held_exclusive(l)        do {                    \
 379                 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0));    \
 380         } while (0)
 381
 382 #define lockdep_assert_held_read(l)     do {                            \
 383                 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1));    \
 384         } while (0)
 385
 386 #define lockdep_assert_held_once(l)     do {                            \
 387                 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));       \
 388         } while (0)
 389
 390 #define lockdep_recursing(tsk)  ((tsk)->lockdep_recursion)
 391
 392 #define lockdep_pin_lock(l)     lock_pin_lock(&(l)->dep_map)
 393 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
 394 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
 395
 396 #else /* !CONFIG_LOCKDEP */
 397
 398 static inline void lockdep_off(void)
 399 {
 400 }
 401
 402 static inline void lockdep_on(void)
 403 {
 404 }
 405
 406 # define lock_acquire(l, s, t, r, c, n, i)      do { } while (0)
 407 # define lock_release(l, n, i)                  do { } while (0)
 408 # define lock_downgrade(l, i)                   do { } while (0)
 409 # define lock_set_class(l, n, k, s, i)          do { } while (0)
 410 # define lock_set_subclass(l, s, i)             do { } while (0)
 411 # define lockdep_info()                         do { } while (0)
 412 # define lockdep_init_map(lock, name, key, sub) \
 413                 do { (void)(name); (void)(key); } while (0)
 414 # define lockdep_set_class(lock, key)           do { (void)(key); } while (0)
 415 # define lockdep_set_class_and_name(lock, key, name) \
 416                 do { (void)(key); (void)(name); } while (0)
 417 #define lockdep_set_class_and_subclass(lock, key, sub) \
 418                 do { (void)(key); } while (0)
 419 #define lockdep_set_subclass(lock, sub)         do { } while (0)
 420
 421 #define lockdep_set_novalidate_class(lock) do { } while (0)
 422
 423 /*
 424  * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
 425  * case since the result is not well defined and the caller should rather
 426  * #ifdef the call himself.
 427  */
 428
 429 # define INIT_LOCKDEP
 430 # define lockdep_reset()                do { debug_locks = 1; } while (0)
 431 # define lockdep_free_key_range(start, size)    do { } while (0)
 432 # define lockdep_sys_exit()                     do { } while (0)
 433 /*
 434  * The class key takes no space if lockdep is disabled:
 435  */
 436 struct lock_class_key { };
 437
 438 /*
 439  * The lockdep_map takes no space if lockdep is disabled:
 440  */
 441 struct lockdep_map { };
 442
 443 #define lockdep_depth(tsk)      (0)
 444
 445 #define lockdep_is_held_type(l, r)              (1)
 446
 447 #define lockdep_assert_held(l)                  do { (void)(l); } while (0)
 448 #define lockdep_assert_held_exclusive(l)        do { (void)(l); } while (0)
 449 #define lockdep_assert_held_read(l)             do { (void)(l); } while (0)
 450 #define lockdep_assert_held_once(l)             do { (void)(l); } while (0)
 451
 452 #define lockdep_recursing(tsk)                  (0)
 453
 454 struct pin_cookie { };
 455
 456 #define NIL_COOKIE (struct pin_cookie){ }
 457
 458 #define lockdep_pin_lock(l)                     ({ struct pin_cookie cookie; cookie; })
 459 #define lockdep_repin_lock(l, c)                do { (void)(l); (void)(c); } while (0)
 460 #define lockdep_unpin_lock(l, c)                do { (void)(l); (void)(c); } while (0)
 461
 462 #endif /* !LOCKDEP */
 463
 464 enum xhlock_context_t {
 465         XHLOCK_HARD,
 466         XHLOCK_SOFT,
 467         XHLOCK_CTX_NR,
 468 };
 469
 470 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
 471 /*
 472  * To initialize a lockdep_map statically use this macro.
 473  * Note that _name must not be NULL.
 474  */
 475 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
 476         { .name = (_name), .key = (void *)(_key), }
 477
 478 static inline void lockdep_invariant_state(bool force) {}
 479 static inline void lockdep_init_task(struct task_struct *task) {}
 480 static inline void lockdep_free_task(struct task_struct *task) {}
 481
 482 #ifdef CONFIG_LOCK_STAT
 483
 484 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
 485 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
 486
 487 #define LOCK_CONTENDED(_lock, try, lock)                        \
 488 do {                                                            \
 489         if (!try(_lock)) {                                      \
 490                 lock_contended(&(_lock)->dep_map, _RET_IP_);    \
 491                 lock(_lock);                                    \
 492         }                                                       \
 493         lock_acquired(&(_lock)->dep_map, _RET_IP_);                     \
 494 } while (0)
 495
 496 #define LOCK_CONTENDED_RETURN(_lock, try, lock)                 \
 497 ({                                                              \
 498         int ____err = 0;                                        \
 499         if (!try(_lock)) {                                      \
 500                 lock_contended(&(_lock)->dep_map, _RET_IP_);    \
 501                 ____err = lock(_lock);                          \
 502         }                                                       \
 503         if (!____err)                                           \
 504                 lock_acquired(&(_lock)->dep_map, _RET_IP_);     \
 505         ____err;                                                \
 506 })
 507
 508 #else /* CONFIG_LOCK_STAT */
 509
 510 #define lock_contended(lockdep_map, ip) do {} while (0)
 511 #define lock_acquired(lockdep_map, ip) do {} while (0)
 512
 513 #define LOCK_CONTENDED(_lock, try, lock) \
 514         lock(_lock)
 515
 516 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
 517         lock(_lock)
 518
 519 #endif /* CONFIG_LOCK_STAT */
 520
 521 #ifdef CONFIG_LOCKDEP
 522
 523 /*
 524  * On lockdep we dont want the hand-coded irq-enable of
 525  * _raw_*_lock_flags() code, because lockdep assumes
 526  * that interrupts are not re-enabled during lock-acquire:
 527  */
 528 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
 529         LOCK_CONTENDED((_lock), (try), (lock))
 530
 531 #else /* CONFIG_LOCKDEP */
 532
 533 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
 534         lockfl((_lock), (flags))
 535
 536 #endif /* CONFIG_LOCKDEP */
 537
 538 #ifdef CONFIG_TRACE_IRQFLAGS
 539 extern void print_irqtrace_events(struct task_struct *curr);
 540 #else
 541 static inline void print_irqtrace_events(struct task_struct *curr)
 542 {
 543 }
 544 #endif
 545
 546 /*
 547  * For trivial one-depth nesting of a lock-class, the following
 548  * global define can be used. (Subsystems with multiple levels
 549  * of nesting should define their own lock-nesting subclasses.)
 550  */
 551 #define SINGLE_DEPTH_NESTING                    1
 552
 553 /*
 554  * Map the dependency ops to NOP or to real lockdep ops, depending
 555  * on the per lock-class debug mode:
 556  */
 557
 558 #define lock_acquire_exclusive(l, s, t, n, i)           lock_acquire(l, s, t, 0, 1, n, i)
 559 #define lock_acquire_shared(l, s, t, n, i)              lock_acquire(l, s, t, 1, 1, n, i)
 560 #define lock_acquire_shared_recursive(l, s, t, n, i)    lock_acquire(l, s, t, 2, 1, n, i)
 561
 562 #define spin_acquire(l, s, t, i)                lock_acquire_exclusive(l, s, t, NULL, i)
 563 #define spin_acquire_nest(l, s, t, n, i)        lock_acquire_exclusive(l, s, t, n, i)
 564 #define spin_release(l, n, i)                   lock_release(l, n, i)
 565
 566 #define rwlock_acquire(l, s, t, i)              lock_acquire_exclusive(l, s, t, NULL, i)
 567 #define rwlock_acquire_read(l, s, t, i)         lock_acquire_shared_recursive(l, s, t, NULL, i)
 568 #define rwlock_release(l, n, i)                 lock_release(l, n, i)
 569
 570 #define seqcount_acquire(l, s, t, i)            lock_acquire_exclusive(l, s, t, NULL, i)
 571 #define seqcount_acquire_read(l, s, t, i)       lock_acquire_shared_recursive(l, s, t, NULL, i)
 572 #define seqcount_release(l, n, i)               lock_release(l, n, i)
 573
 574 #define mutex_acquire(l, s, t, i)               lock_acquire_exclusive(l, s, t, NULL, i)
 575 #define mutex_acquire_nest(l, s, t, n, i)       lock_acquire_exclusive(l, s, t, n, i)
 576 #define mutex_release(l, n, i)                  lock_release(l, n, i)
 577
 578 #define rwsem_acquire(l, s, t, i)               lock_acquire_exclusive(l, s, t, NULL, i)
 579 #define rwsem_acquire_nest(l, s, t, n, i)       lock_acquire_exclusive(l, s, t, n, i)
 580 #define rwsem_acquire_read(l, s, t, i)          lock_acquire_shared(l, s, t, NULL, i)
 581 #define rwsem_release(l, n, i)                  lock_release(l, n, i)
 582
 583 #define lock_map_acquire(l)                     lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
 584 #define lock_map_acquire_read(l)                lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
 585 #define lock_map_acquire_tryread(l)             lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
 586 #define lock_map_release(l)                     lock_release(l, 1, _THIS_IP_)
 587
 588 #ifdef CONFIG_PROVE_LOCKING
 589 # define might_lock(lock)                                               \
 590 do {                                                                    \
 591         typecheck(struct lockdep_map *, &(lock)->dep_map);              \
 592         lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_);    \
 593         lock_release(&(lock)->dep_map, 0, _THIS_IP_);                   \
 594 } while (0)
 595 # define might_lock_read(lock)                                          \
 596 do {                                                                    \
 597         typecheck(struct lockdep_map *, &(lock)->dep_map);              \
 598         lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_);    \
 599         lock_release(&(lock)->dep_map, 0, _THIS_IP_);                   \
 600 } while (0)
 601
 602 #define lockdep_assert_irqs_enabled()   do {                            \
 603                 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
 604                           !current->hardirqs_enabled,                   \
 605                           "IRQs not enabled as expected\n");            \
 606         } while (0)
 607
 608 #define lockdep_assert_irqs_disabled()  do {                            \
 609                 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
 610                           current->hardirqs_enabled,                    \
 611                           "IRQs not disabled as expected\n");           \
 612         } while (0)
 613
 614 #else
 615 # define might_lock(lock) do { } while (0)
 616 # define might_lock_read(lock) do { } while (0)
 617 # define lockdep_assert_irqs_enabled() do { } while (0)
 618 # define lockdep_assert_irqs_disabled() do { } while (0)
 619 #endif
 620
 621 #ifdef CONFIG_LOCKDEP
 622 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
 623 #else
 624 static inline void
 625 lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 626 {
 627 }
 628 #endif
 629
 630 #endif /* __LINUX_LOCKDEP_H */