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/lockdep-design.txt for more details. 8 */ 9#ifndef __LINUX_LOCKDEP_H 10#define __LINUX_LOCKDEP_H 11 12struct task_struct; 13struct lockdep_map; 14 15/* for sysctl */ 16extern int prove_locking; 17extern 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 */ 39struct lockdep_subclass_key { 40 char __one_byte; 41} __attribute__ ((__packed__)); 42 43struct lock_class_key { 44 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; 45}; 46 47extern struct lock_class_key __lockdep_no_validate__; 48 49#define LOCKSTAT_POINTS 4 50 51/* 52 * The lock-class itself: 53 */ 54struct lock_class { 55 /* 56 * class-hash: 57 */ 58 struct list_head hash_entry; 59 60 /* 61 * global list of all lock-classes: 62 */ 63 struct list_head lock_entry; 64 65 struct lockdep_subclass_key *key; 66 unsigned int subclass; 67 unsigned int dep_gen_id; 68 69 /* 70 * IRQ/softirq usage tracking bits: 71 */ 72 unsigned long usage_mask; 73 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; 74 75 /* 76 * These fields represent a directed graph of lock dependencies, 77 * to every node we attach a list of "forward" and a list of 78 * "backward" graph nodes. 79 */ 80 struct list_head locks_after, locks_before; 81 82 /* 83 * Generation counter, when doing certain classes of graph walking, 84 * to ensure that we check one node only once: 85 */ 86 unsigned int version; 87 88 /* 89 * Statistics counter: 90 */ 91 unsigned long ops; 92 93 const char *name; 94 int name_version; 95 96#ifdef CONFIG_LOCK_STAT 97 unsigned long contention_point[LOCKSTAT_POINTS]; 98 unsigned long contending_point[LOCKSTAT_POINTS]; 99#endif 100}; 101 102#ifdef CONFIG_LOCK_STAT 103struct lock_time { 104 s64 min; 105 s64 max; 106 s64 total; 107 unsigned long nr; 108}; 109 110enum bounce_type { 111 bounce_acquired_write, 112 bounce_acquired_read, 113 bounce_contended_write, 114 bounce_contended_read, 115 nr_bounce_types, 116 117 bounce_acquired = bounce_acquired_write, 118 bounce_contended = bounce_contended_write, 119}; 120 121struct lock_class_stats { 122 unsigned long contention_point[4]; 123 unsigned long contending_point[4]; 124 struct lock_time read_waittime; 125 struct lock_time write_waittime; 126 struct lock_time read_holdtime; 127 struct lock_time write_holdtime; 128 unsigned long bounces[nr_bounce_types]; 129}; 130 131struct lock_class_stats lock_stats(struct lock_class *class); 132void clear_lock_stats(struct lock_class *class); 133#endif 134 135/* 136 * Map the lock object (the lock instance) to the lock-class object. 137 * This is embedded into specific lock instances: 138 */ 139struct lockdep_map { 140 struct lock_class_key *key; 141 struct lock_class *class_cache; 142 const char *name; 143#ifdef CONFIG_LOCK_STAT 144 int cpu; 145 unsigned long ip; 146#endif 147}; 148 149/* 150 * Every lock has a list of other locks that were taken after it. 151 * We only grow the list, never remove from it: 152 */ 153struct lock_list { 154 struct list_head entry; 155 struct lock_class *class; 156 struct stack_trace trace; 157 int distance; 158 159 /* 160 * The parent field is used to implement breadth-first search, and the 161 * bit 0 is reused to indicate if the lock has been accessed in BFS. 162 */ 163 struct lock_list *parent; 164}; 165 166/* 167 * We record lock dependency chains, so that we can cache them: 168 */ 169struct lock_chain { 170 u8 irq_context; 171 u8 depth; 172 u16 base; 173 struct list_head entry; 174 u64 chain_key; 175}; 176 177#define MAX_LOCKDEP_KEYS_BITS 13 178/* 179 * Subtract one because we offset hlock->class_idx by 1 in order 180 * to make 0 mean no class. This avoids overflowing the class_idx 181 * bitfield and hitting the BUG in hlock_class(). 182 */ 183#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) 184 185struct held_lock { 186 /* 187 * One-way hash of the dependency chain up to this point. We 188 * hash the hashes step by step as the dependency chain grows. 189 * 190 * We use it for dependency-caching and we skip detection 191 * passes and dependency-updates if there is a cache-hit, so 192 * it is absolutely critical for 100% coverage of the validator 193 * to have a unique key value for every unique dependency path 194 * that can occur in the system, to make a unique hash value 195 * as likely as possible - hence the 64-bit width. 196 * 197 * The task struct holds the current hash value (initialized 198 * with zero), here we store the previous hash value: 199 */ 200 u64 prev_chain_key; 201 unsigned long acquire_ip; 202 struct lockdep_map *instance; 203 struct lockdep_map *nest_lock; 204#ifdef CONFIG_LOCK_STAT 205 u64 waittime_stamp; 206 u64 holdtime_stamp; 207#endif 208 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; 209 /* 210 * The lock-stack is unified in that the lock chains of interrupt 211 * contexts nest ontop of process context chains, but we 'separate' 212 * the hashes by starting with 0 if we cross into an interrupt 213 * context, and we also keep do not add cross-context lock 214 * dependencies - the lock usage graph walking covers that area 215 * anyway, and we'd just unnecessarily increase the number of 216 * dependencies otherwise. [Note: hardirq and softirq contexts 217 * are separated from each other too.] 218 * 219 * The following field is used to detect when we cross into an 220 * interrupt context: 221 */ 222 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ 223 unsigned int trylock:1; /* 16 bits */ 224 225 unsigned int read:2; /* see lock_acquire() comment */ 226 unsigned int check:2; /* see lock_acquire() comment */ 227 unsigned int hardirqs_off:1; 228 unsigned int references:11; /* 32 bits */ 229}; 230 231/* 232 * Initialization, self-test and debugging-output methods: 233 */ 234extern void lockdep_init(void); 235extern void lockdep_info(void); 236extern void lockdep_reset(void); 237extern void lockdep_reset_lock(struct lockdep_map *lock); 238extern void lockdep_free_key_range(void *start, unsigned long size); 239extern void lockdep_sys_exit(void); 240 241extern void lockdep_off(void); 242extern void lockdep_on(void); 243 244/* 245 * These methods are used by specific locking variants (spinlocks, 246 * rwlocks, mutexes and rwsems) to pass init/acquire/release events 247 * to lockdep: 248 */ 249 250extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 251 struct lock_class_key *key, int subclass); 252 253/* 254 * To initialize a lockdep_map statically use this macro. 255 * Note that _name must not be NULL. 256 */ 257#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ 258 { .name = (_name), .key = (void *)(_key), } 259 260/* 261 * Reinitialize a lock key - for cases where there is special locking or 262 * special initialization of locks so that the validator gets the scope 263 * of dependencies wrong: they are either too broad (they need a class-split) 264 * or they are too narrow (they suffer from a false class-split): 265 */ 266#define lockdep_set_class(lock, key) \ 267 lockdep_init_map(&(lock)->dep_map, #key, key, 0) 268#define lockdep_set_class_and_name(lock, key, name) \ 269 lockdep_init_map(&(lock)->dep_map, name, key, 0) 270#define lockdep_set_class_and_subclass(lock, key, sub) \ 271 lockdep_init_map(&(lock)->dep_map, #key, key, sub) 272#define lockdep_set_subclass(lock, sub) \ 273 lockdep_init_map(&(lock)->dep_map, #lock, \ 274 (lock)->dep_map.key, sub) 275 276#define lockdep_set_novalidate_class(lock) \ 277 lockdep_set_class(lock, &__lockdep_no_validate__) 278/* 279 * Compare locking classes 280 */ 281#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) 282 283static inline int lockdep_match_key(struct lockdep_map *lock, 284 struct lock_class_key *key) 285{ 286 return lock->key == key; 287} 288 289/* 290 * Acquire a lock. 291 * 292 * Values for "read": 293 * 294 * 0: exclusive (write) acquire 295 * 1: read-acquire (no recursion allowed) 296 * 2: read-acquire with same-instance recursion allowed 297 * 298 * Values for check: 299 * 300 * 0: disabled 301 * 1: simple checks (freeing, held-at-exit-time, etc.) 302 * 2: full validation 303 */ 304extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 305 int trylock, int read, int check, 306 struct lockdep_map *nest_lock, unsigned long ip); 307 308extern void lock_release(struct lockdep_map *lock, int nested, 309 unsigned long ip); 310 311#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) 312 313extern int lock_is_held(struct lockdep_map *lock); 314 315extern void lock_set_class(struct lockdep_map *lock, const char *name, 316 struct lock_class_key *key, unsigned int subclass, 317 unsigned long ip); 318 319static inline void lock_set_subclass(struct lockdep_map *lock, 320 unsigned int subclass, unsigned long ip) 321{ 322 lock_set_class(lock, lock->name, lock->key, subclass, ip); 323} 324 325extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask); 326extern void lockdep_clear_current_reclaim_state(void); 327extern void lockdep_trace_alloc(gfp_t mask); 328 329# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0, 330 331#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) 332 333#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l)) 334 335#else /* !LOCKDEP */ 336 337static inline void lockdep_off(void) 338{ 339} 340 341static inline void lockdep_on(void) 342{ 343} 344 345# define lock_acquire(l, s, t, r, c, n, i) do { } while (0) 346# define lock_release(l, n, i) do { } while (0) 347# define lock_set_class(l, n, k, s, i) do { } while (0) 348# define lock_set_subclass(l, s, i) do { } while (0) 349# define lockdep_set_current_reclaim_state(g) do { } while (0) 350# define lockdep_clear_current_reclaim_state() do { } while (0) 351# define lockdep_trace_alloc(g) do { } while (0) 352# define lockdep_init() do { } while (0) 353# define lockdep_info() do { } while (0) 354# define lockdep_init_map(lock, name, key, sub) \ 355 do { (void)(name); (void)(key); } while (0) 356# define lockdep_set_class(lock, key) do { (void)(key); } while (0) 357# define lockdep_set_class_and_name(lock, key, name) \ 358 do { (void)(key); (void)(name); } while (0) 359#define lockdep_set_class_and_subclass(lock, key, sub) \ 360 do { (void)(key); } while (0) 361#define lockdep_set_subclass(lock, sub) do { } while (0) 362 363#define lockdep_set_novalidate_class(lock) do { } while (0) 364 365/* 366 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP 367 * case since the result is not well defined and the caller should rather 368 * #ifdef the call himself. 369 */ 370 371# define INIT_LOCKDEP 372# define lockdep_reset() do { debug_locks = 1; } while (0) 373# define lockdep_free_key_range(start, size) do { } while (0) 374# define lockdep_sys_exit() do { } while (0) 375/* 376 * The class key takes no space if lockdep is disabled: 377 */ 378struct lock_class_key { }; 379 380#define lockdep_depth(tsk) (0) 381 382#define lockdep_assert_held(l) do { } while (0) 383 384#endif /* !LOCKDEP */ 385 386#ifdef CONFIG_LOCK_STAT 387 388extern void lock_contended(struct lockdep_map *lock, unsigned long ip); 389extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); 390 391#define LOCK_CONTENDED(_lock, try, lock) \ 392do { \ 393 if (!try(_lock)) { \ 394 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 395 lock(_lock); \ 396 } \ 397 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 398} while (0) 399 400#else /* CONFIG_LOCK_STAT */ 401 402#define lock_contended(lockdep_map, ip) do {} while (0) 403#define lock_acquired(lockdep_map, ip) do {} while (0) 404 405#define LOCK_CONTENDED(_lock, try, lock) \ 406 lock(_lock) 407 408#endif /* CONFIG_LOCK_STAT */ 409 410#ifdef CONFIG_LOCKDEP 411 412/* 413 * On lockdep we dont want the hand-coded irq-enable of 414 * _raw_*_lock_flags() code, because lockdep assumes 415 * that interrupts are not re-enabled during lock-acquire: 416 */ 417#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 418 LOCK_CONTENDED((_lock), (try), (lock)) 419 420#else /* CONFIG_LOCKDEP */ 421 422#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 423 lockfl((_lock), (flags)) 424 425#endif /* CONFIG_LOCKDEP */ 426 427#ifdef CONFIG_GENERIC_HARDIRQS 428extern void early_init_irq_lock_class(void); 429#else 430static inline void early_init_irq_lock_class(void) 431{ 432} 433#endif 434 435#ifdef CONFIG_TRACE_IRQFLAGS 436extern void early_boot_irqs_off(void); 437extern void early_boot_irqs_on(void); 438extern void print_irqtrace_events(struct task_struct *curr); 439#else 440static inline void early_boot_irqs_off(void) 441{ 442} 443static inline void early_boot_irqs_on(void) 444{ 445} 446static inline void print_irqtrace_events(struct task_struct *curr) 447{ 448} 449#endif 450 451/* 452 * For trivial one-depth nesting of a lock-class, the following 453 * global define can be used. (Subsystems with multiple levels 454 * of nesting should define their own lock-nesting subclasses.) 455 */ 456#define SINGLE_DEPTH_NESTING 1 457 458/* 459 * Map the dependency ops to NOP or to real lockdep ops, depending 460 * on the per lock-class debug mode: 461 */ 462 463#ifdef CONFIG_DEBUG_LOCK_ALLOC 464# ifdef CONFIG_PROVE_LOCKING 465# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 466# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) 467# else 468# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 469# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i) 470# endif 471# define spin_release(l, n, i) lock_release(l, n, i) 472#else 473# define spin_acquire(l, s, t, i) do { } while (0) 474# define spin_release(l, n, i) do { } while (0) 475#endif 476 477#ifdef CONFIG_DEBUG_LOCK_ALLOC 478# ifdef CONFIG_PROVE_LOCKING 479# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 480# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i) 481# else 482# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 483# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i) 484# endif 485# define rwlock_release(l, n, i) lock_release(l, n, i) 486#else 487# define rwlock_acquire(l, s, t, i) do { } while (0) 488# define rwlock_acquire_read(l, s, t, i) do { } while (0) 489# define rwlock_release(l, n, i) do { } while (0) 490#endif 491 492#ifdef CONFIG_DEBUG_LOCK_ALLOC 493# ifdef CONFIG_PROVE_LOCKING 494# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 495# else 496# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 497# endif 498# define mutex_release(l, n, i) lock_release(l, n, i) 499#else 500# define mutex_acquire(l, s, t, i) do { } while (0) 501# define mutex_release(l, n, i) do { } while (0) 502#endif 503 504#ifdef CONFIG_DEBUG_LOCK_ALLOC 505# ifdef CONFIG_PROVE_LOCKING 506# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 507# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) 508# else 509# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 510# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) 511# endif 512# define rwsem_release(l, n, i) lock_release(l, n, i) 513#else 514# define rwsem_acquire(l, s, t, i) do { } while (0) 515# define rwsem_acquire_read(l, s, t, i) do { } while (0) 516# define rwsem_release(l, n, i) do { } while (0) 517#endif 518 519#ifdef CONFIG_DEBUG_LOCK_ALLOC 520# ifdef CONFIG_PROVE_LOCKING 521# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_) 522# else 523# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_) 524# endif 525# define lock_map_release(l) lock_release(l, 1, _THIS_IP_) 526#else 527# define lock_map_acquire(l) do { } while (0) 528# define lock_map_release(l) do { } while (0) 529#endif 530 531#ifdef CONFIG_PROVE_LOCKING 532# define might_lock(lock) \ 533do { \ 534 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 535 lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \ 536 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 537} while (0) 538# define might_lock_read(lock) \ 539do { \ 540 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 541 lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \ 542 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 543} while (0) 544#else 545# define might_lock(lock) do { } while (0) 546# define might_lock_read(lock) do { } while (0) 547#endif 548 549#ifdef CONFIG_PROVE_RCU 550extern void lockdep_rcu_dereference(const char *file, const int line); 551#endif 552 553#endif /* __LINUX_LOCKDEP_H */ 554