release/src-rt-6.x/linux/linux-2.6/include/linux/lockdep.h

   1 /*
   2  * Runtime locking correctness validator
   3  *
   4  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   5  *
   6  * see Documentation/lockdep-design.txt for more details.
   7  */
   8 #ifndef __LINUX_LOCKDEP_H
   9 #define __LINUX_LOCKDEP_H
  10
  11 struct task_struct;
  12
  13 #ifdef CONFIG_LOCKDEP
  14
  15 #include <linux/linkage.h>
  16 #include <linux/list.h>
  17 #include <linux/debug_locks.h>
  18 #include <linux/stacktrace.h>
  19
  20 /*
  21  * Lock-class usage-state bits:
  22  */
  23 enum lock_usage_bit
  24 {
  25         LOCK_USED = 0,
  26         LOCK_USED_IN_HARDIRQ,
  27         LOCK_USED_IN_SOFTIRQ,
  28         LOCK_ENABLED_SOFTIRQS,
  29         LOCK_ENABLED_HARDIRQS,
  30         LOCK_USED_IN_HARDIRQ_READ,
  31         LOCK_USED_IN_SOFTIRQ_READ,
  32         LOCK_ENABLED_SOFTIRQS_READ,
  33         LOCK_ENABLED_HARDIRQS_READ,
  34         LOCK_USAGE_STATES
  35 };
  36
  37 /*
  38  * Usage-state bitmasks:
  39  */
  40 #define LOCKF_USED                      (1 << LOCK_USED)
  41 #define LOCKF_USED_IN_HARDIRQ           (1 << LOCK_USED_IN_HARDIRQ)
  42 #define LOCKF_USED_IN_SOFTIRQ           (1 << LOCK_USED_IN_SOFTIRQ)
  43 #define LOCKF_ENABLED_HARDIRQS          (1 << LOCK_ENABLED_HARDIRQS)
  44 #define LOCKF_ENABLED_SOFTIRQS          (1 << LOCK_ENABLED_SOFTIRQS)
  45
  46 #define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS)
  47 #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
  48
  49 #define LOCKF_USED_IN_HARDIRQ_READ      (1 << LOCK_USED_IN_HARDIRQ_READ)
  50 #define LOCKF_USED_IN_SOFTIRQ_READ      (1 << LOCK_USED_IN_SOFTIRQ_READ)
  51 #define LOCKF_ENABLED_HARDIRQS_READ     (1 << LOCK_ENABLED_HARDIRQS_READ)
  52 #define LOCKF_ENABLED_SOFTIRQS_READ     (1 << LOCK_ENABLED_SOFTIRQS_READ)
  53
  54 #define LOCKF_ENABLED_IRQS_READ \
  55                 (LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ)
  56 #define LOCKF_USED_IN_IRQ_READ \
  57                 (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
  58
  59 #define MAX_LOCKDEP_SUBCLASSES          8UL
  60
  61 /*
  62  * Lock-classes are keyed via unique addresses, by embedding the
  63  * lockclass-key into the kernel (or module) .data section. (For
  64  * static locks we use the lock address itself as the key.)
  65  */
  66 struct lockdep_subclass_key {
  67         char __one_byte;
  68 } __attribute__ ((__packed__));
  69
  70 struct lock_class_key {
  71         struct lockdep_subclass_key     subkeys[MAX_LOCKDEP_SUBCLASSES];
  72 };
  73
  74 /*
  75  * The lock-class itself:
  76  */
  77 struct lock_class {
  78         /*
  79          * class-hash:
  80          */
  81         struct list_head                hash_entry;
  82
  83         /*
  84          * global list of all lock-classes:
  85          */
  86         struct list_head                lock_entry;
  87
  88         struct lockdep_subclass_key     *key;
  89         unsigned int                    subclass;
  90
  91         /*
  92          * IRQ/softirq usage tracking bits:
  93          */
  94         unsigned long                   usage_mask;
  95         struct stack_trace              usage_traces[LOCK_USAGE_STATES];
  96
  97         /*
  98          * These fields represent a directed graph of lock dependencies,
  99          * to every node we attach a list of "forward" and a list of
 100          * "backward" graph nodes.
 101          */
 102         struct list_head                locks_after, locks_before;
 103
 104         /*
 105          * Generation counter, when doing certain classes of graph walking,
 106          * to ensure that we check one node only once:
 107          */
 108         unsigned int                    version;
 109
 110         /*
 111          * Statistics counter:
 112          */
 113         unsigned long                   ops;
 114
 115         const char                      *name;
 116         int                             name_version;
 117 };
 118
 119 /*
 120  * Map the lock object (the lock instance) to the lock-class object.
 121  * This is embedded into specific lock instances:
 122  */
 123 struct lockdep_map {
 124         struct lock_class_key           *key;
 125         struct lock_class               *class_cache;
 126         const char                      *name;
 127 };
 128
 129 /*
 130  * Every lock has a list of other locks that were taken after it.
 131  * We only grow the list, never remove from it:
 132  */
 133 struct lock_list {
 134         struct list_head                entry;
 135         struct lock_class               *class;
 136         struct stack_trace              trace;
 137         int                             distance;
 138 };
 139
 140 /*
 141  * We record lock dependency chains, so that we can cache them:
 142  */
 143 struct lock_chain {
 144         struct list_head                entry;
 145         u64                             chain_key;
 146 };
 147
 148 struct held_lock {
 149         /*
 150          * One-way hash of the dependency chain up to this point. We
 151          * hash the hashes step by step as the dependency chain grows.
 152          *
 153          * We use it for dependency-caching and we skip detection
 154          * passes and dependency-updates if there is a cache-hit, so
 155          * it is absolutely critical for 100% coverage of the validator
 156          * to have a unique key value for every unique dependency path
 157          * that can occur in the system, to make a unique hash value
 158          * as likely as possible - hence the 64-bit width.
 159          *
 160          * The task struct holds the current hash value (initialized
 161          * with zero), here we store the previous hash value:
 162          */
 163         u64                             prev_chain_key;
 164         struct lock_class               *class;
 165         unsigned long                   acquire_ip;
 166         struct lockdep_map              *instance;
 167
 168         /*
 169          * The lock-stack is unified in that the lock chains of interrupt
 170          * contexts nest ontop of process context chains, but we 'separate'
 171          * the hashes by starting with 0 if we cross into an interrupt
 172          * context, and we also keep do not add cross-context lock
 173          * dependencies - the lock usage graph walking covers that area
 174          * anyway, and we'd just unnecessarily increase the number of
 175          * dependencies otherwise. [Note: hardirq and softirq contexts
 176          * are separated from each other too.]
 177          *
 178          * The following field is used to detect when we cross into an
 179          * interrupt context:
 180          */
 181         int                             irq_context;
 182         int                             trylock;
 183         int                             read;
 184         int                             check;
 185         int                             hardirqs_off;
 186 };
 187
 188 /*
 189  * Initialization, self-test and debugging-output methods:
 190  */
 191 extern void lockdep_init(void);
 192 extern void lockdep_info(void);
 193 extern void lockdep_reset(void);
 194 extern void lockdep_reset_lock(struct lockdep_map *lock);
 195 extern void lockdep_free_key_range(void *start, unsigned long size);
 196
 197 extern void lockdep_off(void);
 198 extern void lockdep_on(void);
 199
 200 /*
 201  * These methods are used by specific locking variants (spinlocks,
 202  * rwlocks, mutexes and rwsems) to pass init/acquire/release events
 203  * to lockdep:
 204  */
 205
 206 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
 207                              struct lock_class_key *key, int subclass);
 208
 209 /*
 210  * To initialize a lockdep_map statically use this macro.
 211  * Note that _name must not be NULL.
 212  */
 213 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
 214         { .name = (_name), .key = (void *)(_key), }
 215
 216 /*
 217  * Reinitialize a lock key - for cases where there is special locking or
 218  * special initialization of locks so that the validator gets the scope
 219  * of dependencies wrong: they are either too broad (they need a class-split)
 220  * or they are too narrow (they suffer from a false class-split):
 221  */
 222 #define lockdep_set_class(lock, key) \
 223                 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
 224 #define lockdep_set_class_and_name(lock, key, name) \
 225                 lockdep_init_map(&(lock)->dep_map, name, key, 0)
 226 #define lockdep_set_class_and_subclass(lock, key, sub) \
 227                 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
 228 #define lockdep_set_subclass(lock, sub) \
 229                 lockdep_init_map(&(lock)->dep_map, #lock, \
 230                                  (lock)->dep_map.key, sub)
 231
 232 /*
 233  * Acquire a lock.
 234  *
 235  * Values for "read":
 236  *
 237  *   0: exclusive (write) acquire
 238  *   1: read-acquire (no recursion allowed)
 239  *   2: read-acquire with same-instance recursion allowed
 240  *
 241  * Values for check:
 242  *
 243  *   0: disabled
 244  *   1: simple checks (freeing, held-at-exit-time, etc.)
 245  *   2: full validation
 246  */
 247 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 248                          int trylock, int read, int check, unsigned long ip);
 249
 250 extern void lock_release(struct lockdep_map *lock, int nested,
 251                          unsigned long ip);
 252
 253 # define INIT_LOCKDEP                           .lockdep_recursion = 0,
 254
 255 #define lockdep_depth(tsk)      (debug_locks ? (tsk)->lockdep_depth : 0)
 256
 257 #else /* !LOCKDEP */
 258
 259 static inline void lockdep_off(void)
 260 {
 261 }
 262
 263 static inline void lockdep_on(void)
 264 {
 265 }
 266
 267 # define lock_acquire(l, s, t, r, c, i)         do { } while (0)
 268 # define lock_release(l, n, i)                  do { } while (0)
 269 # define lockdep_init()                         do { } while (0)
 270 # define lockdep_info()                         do { } while (0)
 271 # define lockdep_init_map(lock, name, key, sub) do { (void)(key); } while (0)
 272 # define lockdep_set_class(lock, key)           do { (void)(key); } while (0)
 273 # define lockdep_set_class_and_name(lock, key, name) \
 274                 do { (void)(key); } while (0)
 275 #define lockdep_set_class_and_subclass(lock, key, sub) \
 276                 do { (void)(key); } while (0)
 277 #define lockdep_set_subclass(lock, sub)         do { } while (0)
 278
 279 # define INIT_LOCKDEP
 280 # define lockdep_reset()                do { debug_locks = 1; } while (0)
 281 # define lockdep_free_key_range(start, size)    do { } while (0)
 282 /*
 283  * The class key takes no space if lockdep is disabled:
 284  */
 285 struct lock_class_key { };
 286
 287 #define lockdep_depth(tsk)      (0)
 288
 289 #endif /* !LOCKDEP */
 290
 291 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
 292 extern void early_init_irq_lock_class(void);
 293 #else
 294 static inline void early_init_irq_lock_class(void)
 295 {
 296 }
 297 #endif
 298
 299 #ifdef CONFIG_TRACE_IRQFLAGS
 300 extern void early_boot_irqs_off(void);
 301 extern void early_boot_irqs_on(void);
 302 extern void print_irqtrace_events(struct task_struct *curr);
 303 #else
 304 static inline void early_boot_irqs_off(void)
 305 {
 306 }
 307 static inline void early_boot_irqs_on(void)
 308 {
 309 }
 310 static inline void print_irqtrace_events(struct task_struct *curr)
 311 {
 312 }
 313 #endif
 314
 315 /*
 316  * For trivial one-depth nesting of a lock-class, the following
 317  * global define can be used. (Subsystems with multiple levels
 318  * of nesting should define their own lock-nesting subclasses.)
 319  */
 320 #define SINGLE_DEPTH_NESTING                    1
 321
 322 /*
 323  * Map the dependency ops to NOP or to real lockdep ops, depending
 324  * on the per lock-class debug mode:
 325  */
 326
 327 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 328 # ifdef CONFIG_PROVE_LOCKING
 329 #  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 2, i)
 330 # else
 331 #  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 1, i)
 332 # endif
 333 # define spin_release(l, n, i)                  lock_release(l, n, i)
 334 #else
 335 # define spin_acquire(l, s, t, i)               do { } while (0)
 336 # define spin_release(l, n, i)                  do { } while (0)
 337 #endif
 338
 339 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 340 # ifdef CONFIG_PROVE_LOCKING
 341 #  define rwlock_acquire(l, s, t, i)            lock_acquire(l, s, t, 0, 2, i)
 342 #  define rwlock_acquire_read(l, s, t, i)       lock_acquire(l, s, t, 2, 2, i)
 343 # else
 344 #  define rwlock_acquire(l, s, t, i)            lock_acquire(l, s, t, 0, 1, i)
 345 #  define rwlock_acquire_read(l, s, t, i)       lock_acquire(l, s, t, 2, 1, i)
 346 # endif
 347 # define rwlock_release(l, n, i)                lock_release(l, n, i)
 348 #else
 349 # define rwlock_acquire(l, s, t, i)             do { } while (0)
 350 # define rwlock_acquire_read(l, s, t, i)        do { } while (0)
 351 # define rwlock_release(l, n, i)                do { } while (0)
 352 #endif
 353
 354 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 355 # ifdef CONFIG_PROVE_LOCKING
 356 #  define mutex_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 2, i)
 357 # else
 358 #  define mutex_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 1, i)
 359 # endif
 360 # define mutex_release(l, n, i)                 lock_release(l, n, i)
 361 #else
 362 # define mutex_acquire(l, s, t, i)              do { } while (0)
 363 # define mutex_release(l, n, i)                 do { } while (0)
 364 #endif
 365
 366 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 367 # ifdef CONFIG_PROVE_LOCKING
 368 #  define rwsem_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 2, i)
 369 #  define rwsem_acquire_read(l, s, t, i)        lock_acquire(l, s, t, 1, 2, i)
 370 # else
 371 #  define rwsem_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 1, i)
 372 #  define rwsem_acquire_read(l, s, t, i)        lock_acquire(l, s, t, 1, 1, i)
 373 # endif
 374 # define rwsem_release(l, n, i)                 lock_release(l, n, i)
 375 #else
 376 # define rwsem_acquire(l, s, t, i)              do { } while (0)
 377 # define rwsem_acquire_read(l, s, t, i)         do { } while (0)
 378 # define rwsem_release(l, n, i)                 do { } while (0)
 379 #endif
 380
 381 #endif /* __LINUX_LOCKDEP_H */