2 * Runtime locking correctness validator
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>
7 * see Documentation/lockdep-design.txt for more details.
9 #ifndef __LINUX_LOCKDEP_H
10 #define __LINUX_LOCKDEP_H
17 #include <linux/linkage.h>
18 #include <linux/list.h>
19 #include <linux/debug_locks.h>
20 #include <linux/stacktrace.h>
23 * Lock-class usage-state bits:
30 LOCK_ENABLED_SOFTIRQS,
31 LOCK_ENABLED_HARDIRQS,
32 LOCK_USED_IN_HARDIRQ_READ,
33 LOCK_USED_IN_SOFTIRQ_READ,
34 LOCK_ENABLED_SOFTIRQS_READ,
35 LOCK_ENABLED_HARDIRQS_READ,
40 * Usage-state bitmasks:
42 #define LOCKF_USED (1 << LOCK_USED)
43 #define LOCKF_USED_IN_HARDIRQ (1 << LOCK_USED_IN_HARDIRQ)
44 #define LOCKF_USED_IN_SOFTIRQ (1 << LOCK_USED_IN_SOFTIRQ)
45 #define LOCKF_ENABLED_HARDIRQS (1 << LOCK_ENABLED_HARDIRQS)
46 #define LOCKF_ENABLED_SOFTIRQS (1 << LOCK_ENABLED_SOFTIRQS)
48 #define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS)
49 #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
51 #define LOCKF_USED_IN_HARDIRQ_READ (1 << LOCK_USED_IN_HARDIRQ_READ)
52 #define LOCKF_USED_IN_SOFTIRQ_READ (1 << LOCK_USED_IN_SOFTIRQ_READ)
53 #define LOCKF_ENABLED_HARDIRQS_READ (1 << LOCK_ENABLED_HARDIRQS_READ)
54 #define LOCKF_ENABLED_SOFTIRQS_READ (1 << LOCK_ENABLED_SOFTIRQS_READ)
56 #define LOCKF_ENABLED_IRQS_READ \
57 (LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ)
58 #define LOCKF_USED_IN_IRQ_READ \
59 (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
61 #define MAX_LOCKDEP_SUBCLASSES 8UL
64 * Lock-classes are keyed via unique addresses, by embedding the
65 * lockclass-key into the kernel (or module) .data section. (For
66 * static locks we use the lock address itself as the key.)
68 struct lockdep_subclass_key {
70 } __attribute__ ((__packed__));
72 struct lock_class_key {
73 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
77 * The lock-class itself:
83 struct list_head hash_entry;
86 * global list of all lock-classes:
88 struct list_head lock_entry;
90 struct lockdep_subclass_key *key;
91 unsigned int subclass;
94 * IRQ/softirq usage tracking bits:
96 unsigned long usage_mask;
97 struct stack_trace usage_traces[LOCK_USAGE_STATES];
100 * These fields represent a directed graph of lock dependencies,
101 * to every node we attach a list of "forward" and a list of
102 * "backward" graph nodes.
104 struct list_head locks_after, locks_before;
107 * Generation counter, when doing certain classes of graph walking,
108 * to ensure that we check one node only once:
110 unsigned int version;
113 * Statistics counter:
120 #ifdef CONFIG_LOCK_STAT
121 unsigned long contention_point[4];
125 #ifdef CONFIG_LOCK_STAT
134 bounce_acquired_write,
135 bounce_acquired_read,
136 bounce_contended_write,
137 bounce_contended_read,
140 bounce_acquired = bounce_acquired_write,
141 bounce_contended = bounce_contended_write,
144 struct lock_class_stats {
145 unsigned long contention_point[4];
146 struct lock_time read_waittime;
147 struct lock_time write_waittime;
148 struct lock_time read_holdtime;
149 struct lock_time write_holdtime;
150 unsigned long bounces[nr_bounce_types];
153 struct lock_class_stats lock_stats(struct lock_class *class);
154 void clear_lock_stats(struct lock_class *class);
158 * Map the lock object (the lock instance) to the lock-class object.
159 * This is embedded into specific lock instances:
162 struct lock_class_key *key;
163 struct lock_class *class_cache;
165 #ifdef CONFIG_LOCK_STAT
171 * Every lock has a list of other locks that were taken after it.
172 * We only grow the list, never remove from it:
175 struct list_head entry;
176 struct lock_class *class;
177 struct stack_trace trace;
182 * We record lock dependency chains, so that we can cache them:
185 struct list_head entry;
191 * One-way hash of the dependency chain up to this point. We
192 * hash the hashes step by step as the dependency chain grows.
194 * We use it for dependency-caching and we skip detection
195 * passes and dependency-updates if there is a cache-hit, so
196 * it is absolutely critical for 100% coverage of the validator
197 * to have a unique key value for every unique dependency path
198 * that can occur in the system, to make a unique hash value
199 * as likely as possible - hence the 64-bit width.
201 * The task struct holds the current hash value (initialized
202 * with zero), here we store the previous hash value:
205 struct lock_class *class;
206 unsigned long acquire_ip;
207 struct lockdep_map *instance;
209 #ifdef CONFIG_LOCK_STAT
214 * The lock-stack is unified in that the lock chains of interrupt
215 * contexts nest ontop of process context chains, but we 'separate'
216 * the hashes by starting with 0 if we cross into an interrupt
217 * context, and we also keep do not add cross-context lock
218 * dependencies - the lock usage graph walking covers that area
219 * anyway, and we'd just unnecessarily increase the number of
220 * dependencies otherwise. [Note: hardirq and softirq contexts
221 * are separated from each other too.]
223 * The following field is used to detect when we cross into an
234 * Initialization, self-test and debugging-output methods:
236 extern void lockdep_init(void);
237 extern void lockdep_info(void);
238 extern void lockdep_reset(void);
239 extern void lockdep_reset_lock(struct lockdep_map *lock);
240 extern void lockdep_free_key_range(void *start, unsigned long size);
241 extern void lockdep_sys_exit(void);
243 extern void lockdep_off(void);
244 extern void lockdep_on(void);
247 * These methods are used by specific locking variants (spinlocks,
248 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
252 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
253 struct lock_class_key *key, int subclass);
256 * Reinitialize a lock key - for cases where there is special locking or
257 * special initialization of locks so that the validator gets the scope
258 * of dependencies wrong: they are either too broad (they need a class-split)
259 * or they are too narrow (they suffer from a false class-split):
261 #define lockdep_set_class(lock, key) \
262 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
263 #define lockdep_set_class_and_name(lock, key, name) \
264 lockdep_init_map(&(lock)->dep_map, name, key, 0)
265 #define lockdep_set_class_and_subclass(lock, key, sub) \
266 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
267 #define lockdep_set_subclass(lock, sub) \
268 lockdep_init_map(&(lock)->dep_map, #lock, \
269 (lock)->dep_map.key, sub)
276 * 0: exclusive (write) acquire
277 * 1: read-acquire (no recursion allowed)
278 * 2: read-acquire with same-instance recursion allowed
283 * 1: simple checks (freeing, held-at-exit-time, etc.)
286 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
287 int trylock, int read, int check, unsigned long ip);
289 extern void lock_release(struct lockdep_map *lock, int nested,
292 # define INIT_LOCKDEP .lockdep_recursion = 0,
294 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
298 static inline void lockdep_off(void)
302 static inline void lockdep_on(void)
306 # define lock_acquire(l, s, t, r, c, i) do { } while (0)
307 # define lock_release(l, n, i) do { } while (0)
308 # define lockdep_init() do { } while (0)
309 # define lockdep_info() do { } while (0)
310 # define lockdep_init_map(lock, name, key, sub) do { (void)(key); } while (0)
311 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
312 # define lockdep_set_class_and_name(lock, key, name) \
313 do { (void)(key); } while (0)
314 #define lockdep_set_class_and_subclass(lock, key, sub) \
315 do { (void)(key); } while (0)
316 #define lockdep_set_subclass(lock, sub) do { } while (0)
318 # define INIT_LOCKDEP
319 # define lockdep_reset() do { debug_locks = 1; } while (0)
320 # define lockdep_free_key_range(start, size) do { } while (0)
321 # define lockdep_sys_exit() do { } while (0)
323 * The class key takes no space if lockdep is disabled:
325 struct lock_class_key { };
327 #define lockdep_depth(tsk) (0)
329 #endif /* !LOCKDEP */
331 #ifdef CONFIG_LOCK_STAT
333 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
334 extern void lock_acquired(struct lockdep_map *lock);
336 #define LOCK_CONTENDED(_lock, try, lock) \
339 lock_contended(&(_lock)->dep_map, _RET_IP_); \
342 lock_acquired(&(_lock)->dep_map); \
345 #else /* CONFIG_LOCK_STAT */
347 #define lock_contended(lockdep_map, ip) do {} while (0)
348 #define lock_acquired(lockdep_map) do {} while (0)
350 #define LOCK_CONTENDED(_lock, try, lock) \
353 #endif /* CONFIG_LOCK_STAT */
355 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
356 extern void early_init_irq_lock_class(void);
358 static inline void early_init_irq_lock_class(void)
363 #ifdef CONFIG_TRACE_IRQFLAGS
364 extern void early_boot_irqs_off(void);
365 extern void early_boot_irqs_on(void);
366 extern void print_irqtrace_events(struct task_struct *curr);
368 static inline void early_boot_irqs_off(void)
371 static inline void early_boot_irqs_on(void)
374 static inline void print_irqtrace_events(struct task_struct *curr)
380 * For trivial one-depth nesting of a lock-class, the following
381 * global define can be used. (Subsystems with multiple levels
382 * of nesting should define their own lock-nesting subclasses.)
384 #define SINGLE_DEPTH_NESTING 1
387 * Map the dependency ops to NOP or to real lockdep ops, depending
388 * on the per lock-class debug mode:
391 #ifdef CONFIG_DEBUG_LOCK_ALLOC
392 # ifdef CONFIG_PROVE_LOCKING
393 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
395 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
397 # define spin_release(l, n, i) lock_release(l, n, i)
399 # define spin_acquire(l, s, t, i) do { } while (0)
400 # define spin_release(l, n, i) do { } while (0)
403 #ifdef CONFIG_DEBUG_LOCK_ALLOC
404 # ifdef CONFIG_PROVE_LOCKING
405 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
406 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, i)
408 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
409 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, i)
411 # define rwlock_release(l, n, i) lock_release(l, n, i)
413 # define rwlock_acquire(l, s, t, i) do { } while (0)
414 # define rwlock_acquire_read(l, s, t, i) do { } while (0)
415 # define rwlock_release(l, n, i) do { } while (0)
418 #ifdef CONFIG_DEBUG_LOCK_ALLOC
419 # ifdef CONFIG_PROVE_LOCKING
420 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
422 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
424 # define mutex_release(l, n, i) lock_release(l, n, i)
426 # define mutex_acquire(l, s, t, i) do { } while (0)
427 # define mutex_release(l, n, i) do { } while (0)
430 #ifdef CONFIG_DEBUG_LOCK_ALLOC
431 # ifdef CONFIG_PROVE_LOCKING
432 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i)
433 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, i)
435 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i)
436 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, i)
438 # define rwsem_release(l, n, i) lock_release(l, n, i)
440 # define rwsem_acquire(l, s, t, i) do { } while (0)
441 # define rwsem_acquire_read(l, s, t, i) do { } while (0)
442 # define rwsem_release(l, n, i) do { } while (0)
445 #endif /* __LINUX_LOCKDEP_H */