1 /* 2 * Runtime locking correctness validator 3 * 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> 6 * 7 * see Documentation/locking/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 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes 36 * cached in the instance of lockdep_map 37 * 38 * Currently main class (subclass == 0) and signle depth subclass 39 * are cached in lockdep_map. This optimization is mainly targeting 40 * on rq->lock. double_rq_lock() acquires this highly competitive with 41 * single depth. 42 */ 43 #define NR_LOCKDEP_CACHING_CLASSES 2 44 45 /* 46 * Lock-classes are keyed via unique addresses, by embedding the 47 * lockclass-key into the kernel (or module) .data section. (For 48 * static locks we use the lock address itself as the key.) 49 */ 50 struct lockdep_subclass_key { 51 char __one_byte; 52 } __attribute__ ((__packed__)); 53 54 struct lock_class_key { 55 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; 56 }; 57 58 extern struct lock_class_key __lockdep_no_validate__; 59 60 #define LOCKSTAT_POINTS 4 61 62 /* 63 * The lock-class itself: 64 */ 65 struct lock_class { 66 /* 67 * class-hash: 68 */ 69 struct list_head hash_entry; 70 71 /* 72 * global list of all lock-classes: 73 */ 74 struct list_head lock_entry; 75 76 struct lockdep_subclass_key *key; 77 unsigned int subclass; 78 unsigned int dep_gen_id; 79 80 /* 81 * IRQ/softirq usage tracking bits: 82 */ 83 unsigned long usage_mask; 84 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; 85 86 /* 87 * These fields represent a directed graph of lock dependencies, 88 * to every node we attach a list of "forward" and a list of 89 * "backward" graph nodes. 90 */ 91 struct list_head locks_after, locks_before; 92 93 /* 94 * Generation counter, when doing certain classes of graph walking, 95 * to ensure that we check one node only once: 96 */ 97 unsigned int version; 98 99 /* 100 * Statistics counter: 101 */ 102 unsigned long ops; 103 104 const char *name; 105 int name_version; 106 107 #ifdef CONFIG_LOCK_STAT 108 unsigned long contention_point[LOCKSTAT_POINTS]; 109 unsigned long contending_point[LOCKSTAT_POINTS]; 110 #endif 111 }; 112 113 #ifdef CONFIG_LOCK_STAT 114 struct lock_time { 115 s64 min; 116 s64 max; 117 s64 total; 118 unsigned long nr; 119 }; 120 121 enum bounce_type { 122 bounce_acquired_write, 123 bounce_acquired_read, 124 bounce_contended_write, 125 bounce_contended_read, 126 nr_bounce_types, 127 128 bounce_acquired = bounce_acquired_write, 129 bounce_contended = bounce_contended_write, 130 }; 131 132 struct lock_class_stats { 133 unsigned long contention_point[LOCKSTAT_POINTS]; 134 unsigned long contending_point[LOCKSTAT_POINTS]; 135 struct lock_time read_waittime; 136 struct lock_time write_waittime; 137 struct lock_time read_holdtime; 138 struct lock_time write_holdtime; 139 unsigned long bounces[nr_bounce_types]; 140 }; 141 142 struct lock_class_stats lock_stats(struct lock_class *class); 143 void clear_lock_stats(struct lock_class *class); 144 #endif 145 146 /* 147 * Map the lock object (the lock instance) to the lock-class object. 148 * This is embedded into specific lock instances: 149 */ 150 struct lockdep_map { 151 struct lock_class_key *key; 152 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES]; 153 const char *name; 154 #ifdef CONFIG_LOCK_STAT 155 int cpu; 156 unsigned long ip; 157 #endif 158 }; 159 160 static inline void lockdep_copy_map(struct lockdep_map *to, 161 struct lockdep_map *from) 162 { 163 int i; 164 165 *to = *from; 166 /* 167 * Since the class cache can be modified concurrently we could observe 168 * half pointers (64bit arch using 32bit copy insns). Therefore clear 169 * the caches and take the performance hit. 170 * 171 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since 172 * that relies on cache abuse. 173 */ 174 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) 175 to->class_cache[i] = NULL; 176 } 177 178 /* 179 * Every lock has a list of other locks that were taken after it. 180 * We only grow the list, never remove from it: 181 */ 182 struct lock_list { 183 struct list_head entry; 184 struct lock_class *class; 185 struct stack_trace trace; 186 int distance; 187 188 /* 189 * The parent field is used to implement breadth-first search, and the 190 * bit 0 is reused to indicate if the lock has been accessed in BFS. 191 */ 192 struct lock_list *parent; 193 }; 194 195 /* 196 * We record lock dependency chains, so that we can cache them: 197 */ 198 struct lock_chain { 199 u8 irq_context; 200 u8 depth; 201 u16 base; 202 struct list_head entry; 203 u64 chain_key; 204 }; 205 206 #define MAX_LOCKDEP_KEYS_BITS 13 207 /* 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(). 211 */ 212 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) 213 214 struct held_lock { 215 /* 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. 218 * 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. 225 * 226 * The task struct holds the current hash value (initialized 227 * with zero), here we store the previous hash value: 228 */ 229 u64 prev_chain_key; 230 unsigned long acquire_ip; 231 struct lockdep_map *instance; 232 struct lockdep_map *nest_lock; 233 #ifdef CONFIG_LOCK_STAT 234 u64 waittime_stamp; 235 u64 holdtime_stamp; 236 #endif 237 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; 238 /* 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.] 247 * 248 * The following field is used to detect when we cross into an 249 * interrupt context: 250 */ 251 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ 252 unsigned int trylock:1; /* 16 bits */ 253 254 unsigned int read:2; /* see lock_acquire() comment */ 255 unsigned int check:1; /* see lock_acquire() comment */ 256 unsigned int hardirqs_off:1; 257 unsigned int references:12; /* 32 bits */ 258 unsigned int pin_count; 259 }; 260 261 /* 262 * Initialization, self-test and debugging-output methods: 263 */ 264 extern void lockdep_init(void); 265 extern void lockdep_info(void); 266 extern void lockdep_reset(void); 267 extern void lockdep_reset_lock(struct lockdep_map *lock); 268 extern void lockdep_free_key_range(void *start, unsigned long size); 269 extern asmlinkage void lockdep_sys_exit(void); 270 271 extern void lockdep_off(void); 272 extern void lockdep_on(void); 273 274 /* 275 * These methods are used by specific locking variants (spinlocks, 276 * rwlocks, mutexes and rwsems) to pass init/acquire/release events 277 * to lockdep: 278 */ 279 280 extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 281 struct lock_class_key *key, int subclass); 282 283 /* 284 * To initialize a lockdep_map statically use this macro. 285 * Note that _name must not be NULL. 286 */ 287 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ 288 { .name = (_name), .key = (void *)(_key), } 289 290 /* 291 * Reinitialize a lock key - for cases where there is special locking or 292 * special initialization of locks so that the validator gets the scope 293 * of dependencies wrong: they are either too broad (they need a class-split) 294 * or they are too narrow (they suffer from a false class-split): 295 */ 296 #define lockdep_set_class(lock, key) \ 297 lockdep_init_map(&(lock)->dep_map, #key, key, 0) 298 #define lockdep_set_class_and_name(lock, key, name) \ 299 lockdep_init_map(&(lock)->dep_map, name, key, 0) 300 #define lockdep_set_class_and_subclass(lock, key, sub) \ 301 lockdep_init_map(&(lock)->dep_map, #key, key, sub) 302 #define lockdep_set_subclass(lock, sub) \ 303 lockdep_init_map(&(lock)->dep_map, #lock, \ 304 (lock)->dep_map.key, sub) 305 306 #define lockdep_set_novalidate_class(lock) \ 307 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock) 308 /* 309 * Compare locking classes 310 */ 311 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) 312 313 static inline int lockdep_match_key(struct lockdep_map *lock, 314 struct lock_class_key *key) 315 { 316 return lock->key == key; 317 } 318 319 /* 320 * Acquire a lock. 321 * 322 * Values for "read": 323 * 324 * 0: exclusive (write) acquire 325 * 1: read-acquire (no recursion allowed) 326 * 2: read-acquire with same-instance recursion allowed 327 * 328 * Values for check: 329 * 330 * 0: simple checks (freeing, held-at-exit-time, etc.) 331 * 1: full validation 332 */ 333 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 334 int trylock, int read, int check, 335 struct lockdep_map *nest_lock, unsigned long ip); 336 337 extern void lock_release(struct lockdep_map *lock, int nested, 338 unsigned long ip); 339 340 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) 341 342 extern int lock_is_held(struct lockdep_map *lock); 343 344 extern void lock_set_class(struct lockdep_map *lock, const char *name, 345 struct lock_class_key *key, unsigned int subclass, 346 unsigned long ip); 347 348 static inline void lock_set_subclass(struct lockdep_map *lock, 349 unsigned int subclass, unsigned long ip) 350 { 351 lock_set_class(lock, lock->name, lock->key, subclass, ip); 352 } 353 354 extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask); 355 extern void lockdep_clear_current_reclaim_state(void); 356 extern void lockdep_trace_alloc(gfp_t mask); 357 358 extern void lock_pin_lock(struct lockdep_map *lock); 359 extern void lock_unpin_lock(struct lockdep_map *lock); 360 361 # define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0, 362 363 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) 364 365 #define lockdep_assert_held(l) do { \ 366 WARN_ON(debug_locks && !lockdep_is_held(l)); \ 367 } while (0) 368 369 #define lockdep_assert_held_once(l) do { \ 370 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ 371 } while (0) 372 373 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) 374 375 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map) 376 #define lockdep_unpin_lock(l) lock_unpin_lock(&(l)->dep_map) 377 378 #else /* !CONFIG_LOCKDEP */ 379 380 static inline void lockdep_off(void) 381 { 382 } 383 384 static inline void lockdep_on(void) 385 { 386 } 387 388 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0) 389 # define lock_release(l, n, i) do { } while (0) 390 # define lock_set_class(l, n, k, s, i) do { } while (0) 391 # define lock_set_subclass(l, s, i) do { } while (0) 392 # define lockdep_set_current_reclaim_state(g) do { } while (0) 393 # define lockdep_clear_current_reclaim_state() do { } while (0) 394 # define lockdep_trace_alloc(g) do { } while (0) 395 # define lockdep_init() do { } while (0) 396 # define lockdep_info() do { } while (0) 397 # define lockdep_init_map(lock, name, key, sub) \ 398 do { (void)(name); (void)(key); } while (0) 399 # define lockdep_set_class(lock, key) do { (void)(key); } while (0) 400 # define lockdep_set_class_and_name(lock, key, name) \ 401 do { (void)(key); (void)(name); } while (0) 402 #define lockdep_set_class_and_subclass(lock, key, sub) \ 403 do { (void)(key); } while (0) 404 #define lockdep_set_subclass(lock, sub) do { } while (0) 405 406 #define lockdep_set_novalidate_class(lock) do { } while (0) 407 408 /* 409 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP 410 * case since the result is not well defined and the caller should rather 411 * #ifdef the call himself. 412 */ 413 414 # define INIT_LOCKDEP 415 # define lockdep_reset() do { debug_locks = 1; } while (0) 416 # define lockdep_free_key_range(start, size) do { } while (0) 417 # define lockdep_sys_exit() do { } while (0) 418 /* 419 * The class key takes no space if lockdep is disabled: 420 */ 421 struct lock_class_key { }; 422 423 #define lockdep_depth(tsk) (0) 424 425 #define lockdep_assert_held(l) do { (void)(l); } while (0) 426 #define lockdep_assert_held_once(l) do { (void)(l); } while (0) 427 428 #define lockdep_recursing(tsk) (0) 429 430 #define lockdep_pin_lock(l) do { (void)(l); } while (0) 431 #define lockdep_unpin_lock(l) do { (void)(l); } while (0) 432 433 #endif /* !LOCKDEP */ 434 435 #ifdef CONFIG_LOCK_STAT 436 437 extern void lock_contended(struct lockdep_map *lock, unsigned long ip); 438 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); 439 440 #define LOCK_CONTENDED(_lock, try, lock) \ 441 do { \ 442 if (!try(_lock)) { \ 443 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 444 lock(_lock); \ 445 } \ 446 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 447 } while (0) 448 449 #else /* CONFIG_LOCK_STAT */ 450 451 #define lock_contended(lockdep_map, ip) do {} while (0) 452 #define lock_acquired(lockdep_map, ip) do {} while (0) 453 454 #define LOCK_CONTENDED(_lock, try, lock) \ 455 lock(_lock) 456 457 #endif /* CONFIG_LOCK_STAT */ 458 459 #ifdef CONFIG_LOCKDEP 460 461 /* 462 * On lockdep we dont want the hand-coded irq-enable of 463 * _raw_*_lock_flags() code, because lockdep assumes 464 * that interrupts are not re-enabled during lock-acquire: 465 */ 466 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 467 LOCK_CONTENDED((_lock), (try), (lock)) 468 469 #else /* CONFIG_LOCKDEP */ 470 471 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 472 lockfl((_lock), (flags)) 473 474 #endif /* CONFIG_LOCKDEP */ 475 476 #ifdef CONFIG_TRACE_IRQFLAGS 477 extern void print_irqtrace_events(struct task_struct *curr); 478 #else 479 static inline void print_irqtrace_events(struct task_struct *curr) 480 { 481 } 482 #endif 483 484 /* 485 * For trivial one-depth nesting of a lock-class, the following 486 * global define can be used. (Subsystems with multiple levels 487 * of nesting should define their own lock-nesting subclasses.) 488 */ 489 #define SINGLE_DEPTH_NESTING 1 490 491 /* 492 * Map the dependency ops to NOP or to real lockdep ops, depending 493 * on the per lock-class debug mode: 494 */ 495 496 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) 497 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) 498 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) 499 500 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 501 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 502 #define spin_release(l, n, i) lock_release(l, n, i) 503 504 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 505 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) 506 #define rwlock_release(l, n, i) lock_release(l, n, i) 507 508 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 509 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) 510 #define seqcount_release(l, n, i) lock_release(l, n, i) 511 512 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 513 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 514 #define mutex_release(l, n, i) lock_release(l, n, i) 515 516 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 517 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 518 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i) 519 #define rwsem_release(l, n, i) lock_release(l, n, i) 520 521 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_) 522 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_) 523 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_) 524 #define lock_map_release(l) lock_release(l, 1, _THIS_IP_) 525 526 #ifdef CONFIG_PROVE_LOCKING 527 # define might_lock(lock) \ 528 do { \ 529 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 530 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \ 531 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 532 } while (0) 533 # define might_lock_read(lock) \ 534 do { \ 535 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 536 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \ 537 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 538 } while (0) 539 #else 540 # define might_lock(lock) do { } while (0) 541 # define might_lock_read(lock) do { } while (0) 542 #endif 543 544 #ifdef CONFIG_LOCKDEP 545 void lockdep_rcu_suspicious(const char *file, const int line, const char *s); 546 #else 547 static inline void 548 lockdep_rcu_suspicious(const char *file, const int line, const char *s) 549 { 550 } 551 #endif 552 553 #endif /* __LINUX_LOCKDEP_H */ 554