1 /* 2 * Runtime locking correctness validator 3 * 4 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]> 5 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]> 6 * 7 * see Documentation/lockdep-design.txt for more details. 8 */ 9 #ifndef __LINUX_LOCKDEP_H 10 #define __LINUX_LOCKDEP_H 11 12 struct task_struct; 13 struct lockdep_map; 14 15 /* for sysctl */ 16 extern int prove_locking; 17 extern int lock_stat; 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 26 /* 27 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need 28 * the total number of states... :-( 29 */ 30 #define XXX_LOCK_USAGE_STATES (1+3*4) 31 32 #define MAX_LOCKDEP_SUBCLASSES 8UL 33 34 /* 35 * Lock-classes are keyed via unique addresses, by embedding the 36 * lockclass-key into the kernel (or module) .data section. (For 37 * static locks we use the lock address itself as the key.) 38 */ 39 struct lockdep_subclass_key { 40 char __one_byte; 41 } __attribute__ ((__packed__)); 42 43 struct lock_class_key { 44 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; 45 }; 46 47 #define LOCKSTAT_POINTS 4 48 49 /* 50 * The lock-class itself: 51 */ 52 struct lock_class { 53 /* 54 * class-hash: 55 */ 56 struct list_head hash_entry; 57 58 /* 59 * global list of all lock-classes: 60 */ 61 struct list_head lock_entry; 62 63 struct lockdep_subclass_key *key; 64 unsigned int subclass; 65 unsigned int dep_gen_id; 66 67 /* 68 * IRQ/softirq usage tracking bits: 69 */ 70 unsigned long usage_mask; 71 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; 72 73 /* 74 * These fields represent a directed graph of lock dependencies, 75 * to every node we attach a list of "forward" and a list of 76 * "backward" graph nodes. 77 */ 78 struct list_head locks_after, locks_before; 79 80 /* 81 * Generation counter, when doing certain classes of graph walking, 82 * to ensure that we check one node only once: 83 */ 84 unsigned int version; 85 86 /* 87 * Statistics counter: 88 */ 89 unsigned long ops; 90 91 const char *name; 92 int name_version; 93 94 #ifdef CONFIG_LOCK_STAT 95 unsigned long contention_point[LOCKSTAT_POINTS]; 96 unsigned long contending_point[LOCKSTAT_POINTS]; 97 #endif 98 }; 99 100 #ifdef CONFIG_LOCK_STAT 101 struct lock_time { 102 s64 min; 103 s64 max; 104 s64 total; 105 unsigned long nr; 106 }; 107 108 enum bounce_type { 109 bounce_acquired_write, 110 bounce_acquired_read, 111 bounce_contended_write, 112 bounce_contended_read, 113 nr_bounce_types, 114 115 bounce_acquired = bounce_acquired_write, 116 bounce_contended = bounce_contended_write, 117 }; 118 119 struct lock_class_stats { 120 unsigned long contention_point[4]; 121 unsigned long contending_point[4]; 122 struct lock_time read_waittime; 123 struct lock_time write_waittime; 124 struct lock_time read_holdtime; 125 struct lock_time write_holdtime; 126 unsigned long bounces[nr_bounce_types]; 127 }; 128 129 struct lock_class_stats lock_stats(struct lock_class *class); 130 void clear_lock_stats(struct lock_class *class); 131 #endif 132 133 /* 134 * Map the lock object (the lock instance) to the lock-class object. 135 * This is embedded into specific lock instances: 136 */ 137 struct lockdep_map { 138 struct lock_class_key *key; 139 struct lock_class *class_cache; 140 const char *name; 141 #ifdef CONFIG_LOCK_STAT 142 int cpu; 143 unsigned long ip; 144 #endif 145 }; 146 147 /* 148 * Every lock has a list of other locks that were taken after it. 149 * We only grow the list, never remove from it: 150 */ 151 struct lock_list { 152 struct list_head entry; 153 struct lock_class *class; 154 struct stack_trace trace; 155 int distance; 156 157 /* 158 * The parent field is used to implement breadth-first search, and the 159 * bit 0 is reused to indicate if the lock has been accessed in BFS. 160 */ 161 struct lock_list *parent; 162 }; 163 164 /* 165 * We record lock dependency chains, so that we can cache them: 166 */ 167 struct lock_chain { 168 u8 irq_context; 169 u8 depth; 170 u16 base; 171 struct list_head entry; 172 u64 chain_key; 173 }; 174 175 #define MAX_LOCKDEP_KEYS_BITS 13 176 /* 177 * Subtract one because we offset hlock->class_idx by 1 in order 178 * to make 0 mean no class. This avoids overflowing the class_idx 179 * bitfield and hitting the BUG in hlock_class(). 180 */ 181 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) 182 183 struct held_lock { 184 /* 185 * One-way hash of the dependency chain up to this point. We 186 * hash the hashes step by step as the dependency chain grows. 187 * 188 * We use it for dependency-caching and we skip detection 189 * passes and dependency-updates if there is a cache-hit, so 190 * it is absolutely critical for 100% coverage of the validator 191 * to have a unique key value for every unique dependency path 192 * that can occur in the system, to make a unique hash value 193 * as likely as possible - hence the 64-bit width. 194 * 195 * The task struct holds the current hash value (initialized 196 * with zero), here we store the previous hash value: 197 */ 198 u64 prev_chain_key; 199 unsigned long acquire_ip; 200 struct lockdep_map *instance; 201 struct lockdep_map *nest_lock; 202 #ifdef CONFIG_LOCK_STAT 203 u64 waittime_stamp; 204 u64 holdtime_stamp; 205 #endif 206 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; 207 /* 208 * The lock-stack is unified in that the lock chains of interrupt 209 * contexts nest ontop of process context chains, but we 'separate' 210 * the hashes by starting with 0 if we cross into an interrupt 211 * context, and we also keep do not add cross-context lock 212 * dependencies - the lock usage graph walking covers that area 213 * anyway, and we'd just unnecessarily increase the number of 214 * dependencies otherwise. [Note: hardirq and softirq contexts 215 * are separated from each other too.] 216 * 217 * The following field is used to detect when we cross into an 218 * interrupt context: 219 */ 220 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ 221 unsigned int trylock:1; /* 16 bits */ 222 223 unsigned int read:2; /* see lock_acquire() comment */ 224 unsigned int check:2; /* see lock_acquire() comment */ 225 unsigned int hardirqs_off:1; 226 unsigned int references:11; /* 32 bits */ 227 }; 228 229 /* 230 * Initialization, self-test and debugging-output methods: 231 */ 232 extern void lockdep_init(void); 233 extern void lockdep_info(void); 234 extern void lockdep_reset(void); 235 extern void lockdep_reset_lock(struct lockdep_map *lock); 236 extern void lockdep_free_key_range(void *start, unsigned long size); 237 extern void lockdep_sys_exit(void); 238 239 extern void lockdep_off(void); 240 extern void lockdep_on(void); 241 242 /* 243 * These methods are used by specific locking variants (spinlocks, 244 * rwlocks, mutexes and rwsems) to pass init/acquire/release events 245 * to lockdep: 246 */ 247 248 extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 249 struct lock_class_key *key, int subclass); 250 251 /* 252 * To initialize a lockdep_map statically use this macro. 253 * Note that _name must not be NULL. 254 */ 255 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ 256 { .name = (_name), .key = (void *)(_key), } 257 258 /* 259 * Reinitialize a lock key - for cases where there is special locking or 260 * special initialization of locks so that the validator gets the scope 261 * of dependencies wrong: they are either too broad (they need a class-split) 262 * or they are too narrow (they suffer from a false class-split): 263 */ 264 #define lockdep_set_class(lock, key) \ 265 lockdep_init_map(&(lock)->dep_map, #key, key, 0) 266 #define lockdep_set_class_and_name(lock, key, name) \ 267 lockdep_init_map(&(lock)->dep_map, name, key, 0) 268 #define lockdep_set_class_and_subclass(lock, key, sub) \ 269 lockdep_init_map(&(lock)->dep_map, #key, key, sub) 270 #define lockdep_set_subclass(lock, sub) \ 271 lockdep_init_map(&(lock)->dep_map, #lock, \ 272 (lock)->dep_map.key, sub) 273 /* 274 * Compare locking classes 275 */ 276 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) 277 278 static inline int lockdep_match_key(struct lockdep_map *lock, 279 struct lock_class_key *key) 280 { 281 return lock->key == key; 282 } 283 284 /* 285 * Acquire a lock. 286 * 287 * Values for "read": 288 * 289 * 0: exclusive (write) acquire 290 * 1: read-acquire (no recursion allowed) 291 * 2: read-acquire with same-instance recursion allowed 292 * 293 * Values for check: 294 * 295 * 0: disabled 296 * 1: simple checks (freeing, held-at-exit-time, etc.) 297 * 2: full validation 298 */ 299 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 300 int trylock, int read, int check, 301 struct lockdep_map *nest_lock, unsigned long ip); 302 303 extern void lock_release(struct lockdep_map *lock, int nested, 304 unsigned long ip); 305 306 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) 307 308 extern int lock_is_held(struct lockdep_map *lock); 309 310 extern void lock_set_class(struct lockdep_map *lock, const char *name, 311 struct lock_class_key *key, unsigned int subclass, 312 unsigned long ip); 313 314 static inline void lock_set_subclass(struct lockdep_map *lock, 315 unsigned int subclass, unsigned long ip) 316 { 317 lock_set_class(lock, lock->name, lock->key, subclass, ip); 318 } 319 320 extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask); 321 extern void lockdep_clear_current_reclaim_state(void); 322 extern void lockdep_trace_alloc(gfp_t mask); 323 324 # define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0, 325 326 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) 327 328 #define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l)) 329 330 #else /* !LOCKDEP */ 331 332 static inline void lockdep_off(void) 333 { 334 } 335 336 static inline void lockdep_on(void) 337 { 338 } 339 340 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0) 341 # define lock_release(l, n, i) do { } while (0) 342 # define lock_set_class(l, n, k, s, i) do { } while (0) 343 # define lock_set_subclass(l, s, i) do { } while (0) 344 # define lockdep_set_current_reclaim_state(g) do { } while (0) 345 # define lockdep_clear_current_reclaim_state() do { } while (0) 346 # define lockdep_trace_alloc(g) do { } while (0) 347 # define lockdep_init() do { } while (0) 348 # define lockdep_info() do { } 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 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP 359 * case since the result is not well defined and the caller should rather 360 * #ifdef the call himself. 361 */ 362 363 # define INIT_LOCKDEP 364 # define lockdep_reset() do { debug_locks = 1; } while (0) 365 # define lockdep_free_key_range(start, size) do { } while (0) 366 # define lockdep_sys_exit() do { } while (0) 367 /* 368 * The class key takes no space if lockdep is disabled: 369 */ 370 struct lock_class_key { }; 371 372 #define lockdep_depth(tsk) (0) 373 374 #define lockdep_assert_held(l) do { } while (0) 375 376 #endif /* !LOCKDEP */ 377 378 #ifdef CONFIG_LOCK_STAT 379 380 extern void lock_contended(struct lockdep_map *lock, unsigned long ip); 381 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); 382 383 #define LOCK_CONTENDED(_lock, try, lock) \ 384 do { \ 385 if (!try(_lock)) { \ 386 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 387 lock(_lock); \ 388 } \ 389 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 390 } while (0) 391 392 #else /* CONFIG_LOCK_STAT */ 393 394 #define lock_contended(lockdep_map, ip) do {} while (0) 395 #define lock_acquired(lockdep_map, ip) do {} while (0) 396 397 #define LOCK_CONTENDED(_lock, try, lock) \ 398 lock(_lock) 399 400 #endif /* CONFIG_LOCK_STAT */ 401 402 #ifdef CONFIG_LOCKDEP 403 404 /* 405 * On lockdep we dont want the hand-coded irq-enable of 406 * _raw_*_lock_flags() code, because lockdep assumes 407 * that interrupts are not re-enabled during lock-acquire: 408 */ 409 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 410 LOCK_CONTENDED((_lock), (try), (lock)) 411 412 #else /* CONFIG_LOCKDEP */ 413 414 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 415 lockfl((_lock), (flags)) 416 417 #endif /* CONFIG_LOCKDEP */ 418 419 #ifdef CONFIG_GENERIC_HARDIRQS 420 extern void early_init_irq_lock_class(void); 421 #else 422 static inline void early_init_irq_lock_class(void) 423 { 424 } 425 #endif 426 427 #ifdef CONFIG_TRACE_IRQFLAGS 428 extern void early_boot_irqs_off(void); 429 extern void early_boot_irqs_on(void); 430 extern void print_irqtrace_events(struct task_struct *curr); 431 #else 432 static inline void early_boot_irqs_off(void) 433 { 434 } 435 static inline void early_boot_irqs_on(void) 436 { 437 } 438 static inline void print_irqtrace_events(struct task_struct *curr) 439 { 440 } 441 #endif 442 443 /* 444 * For trivial one-depth nesting of a lock-class, the following 445 * global define can be used. (Subsystems with multiple levels 446 * of nesting should define their own lock-nesting subclasses.) 447 */ 448 #define SINGLE_DEPTH_NESTING 1 449 450 /* 451 * Map the dependency ops to NOP or to real lockdep ops, depending 452 * on the per lock-class debug mode: 453 */ 454 455 #ifdef CONFIG_DEBUG_LOCK_ALLOC 456 # ifdef CONFIG_PROVE_LOCKING 457 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 458 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) 459 # else 460 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 461 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i) 462 # endif 463 # define spin_release(l, n, i) lock_release(l, n, i) 464 #else 465 # define spin_acquire(l, s, t, i) do { } while (0) 466 # define spin_release(l, n, i) do { } while (0) 467 #endif 468 469 #ifdef CONFIG_DEBUG_LOCK_ALLOC 470 # ifdef CONFIG_PROVE_LOCKING 471 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 472 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i) 473 # else 474 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 475 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i) 476 # endif 477 # define rwlock_release(l, n, i) lock_release(l, n, i) 478 #else 479 # define rwlock_acquire(l, s, t, i) do { } while (0) 480 # define rwlock_acquire_read(l, s, t, i) do { } while (0) 481 # define rwlock_release(l, n, i) do { } while (0) 482 #endif 483 484 #ifdef CONFIG_DEBUG_LOCK_ALLOC 485 # ifdef CONFIG_PROVE_LOCKING 486 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 487 # else 488 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 489 # endif 490 # define mutex_release(l, n, i) lock_release(l, n, i) 491 #else 492 # define mutex_acquire(l, s, t, i) do { } while (0) 493 # define mutex_release(l, n, i) do { } while (0) 494 #endif 495 496 #ifdef CONFIG_DEBUG_LOCK_ALLOC 497 # ifdef CONFIG_PROVE_LOCKING 498 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 499 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) 500 # else 501 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 502 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) 503 # endif 504 # define rwsem_release(l, n, i) lock_release(l, n, i) 505 #else 506 # define rwsem_acquire(l, s, t, i) do { } while (0) 507 # define rwsem_acquire_read(l, s, t, i) do { } while (0) 508 # define rwsem_release(l, n, i) do { } while (0) 509 #endif 510 511 #ifdef CONFIG_DEBUG_LOCK_ALLOC 512 # ifdef CONFIG_PROVE_LOCKING 513 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_) 514 # else 515 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_) 516 # endif 517 # define lock_map_release(l) lock_release(l, 1, _THIS_IP_) 518 #else 519 # define lock_map_acquire(l) do { } while (0) 520 # define lock_map_release(l) do { } while (0) 521 #endif 522 523 #ifdef CONFIG_PROVE_LOCKING 524 # define might_lock(lock) \ 525 do { \ 526 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 527 lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \ 528 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 529 } while (0) 530 # define might_lock_read(lock) \ 531 do { \ 532 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 533 lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \ 534 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 535 } while (0) 536 #else 537 # define might_lock(lock) do { } while (0) 538 # define might_lock_read(lock) do { } while (0) 539 #endif 540 541 #ifdef CONFIG_PROVE_RCU 542 extern void lockdep_rcu_dereference(const char *file, const int line); 543 #endif 544 545 #endif /* __LINUX_LOCKDEP_H */ 546