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Diffstat (limited to 'include/linux/lockdep.h')
| -rw-r--r-- | include/linux/lockdep.h | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h new file mode 100644 index 000000000..066ba4157 --- /dev/null +++ b/include/linux/lockdep.h @@ -0,0 +1,543 @@ +/* + * Runtime locking correctness validator + * + * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> + * + * see Documentation/locking/lockdep-design.txt for more details. + */ +#ifndef __LINUX_LOCKDEP_H +#define __LINUX_LOCKDEP_H + +struct task_struct; +struct lockdep_map; + +/* for sysctl */ +extern int prove_locking; +extern int lock_stat; + +#ifdef CONFIG_LOCKDEP + +#include <linux/linkage.h> +#include <linux/list.h> +#include <linux/debug_locks.h> +#include <linux/stacktrace.h> + +/* + * We'd rather not expose kernel/lockdep_states.h this wide, but we do need + * the total number of states... :-( + */ +#define XXX_LOCK_USAGE_STATES (1+3*4) + +#define MAX_LOCKDEP_SUBCLASSES 8UL + +/* + * NR_LOCKDEP_CACHING_CLASSES ... Number of classes + * cached in the instance of lockdep_map + * + * Currently main class (subclass == 0) and signle depth subclass + * are cached in lockdep_map. This optimization is mainly targeting + * on rq->lock. double_rq_lock() acquires this highly competitive with + * single depth. + */ +#define NR_LOCKDEP_CACHING_CLASSES 2 + +/* + * Lock-classes are keyed via unique addresses, by embedding the + * lockclass-key into the kernel (or module) .data section. (For + * static locks we use the lock address itself as the key.) + */ +struct lockdep_subclass_key { + char __one_byte; +} __attribute__ ((__packed__)); + +struct lock_class_key { + struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; +}; + +extern struct lock_class_key __lockdep_no_validate__; + +#define LOCKSTAT_POINTS 4 + +/* + * The lock-class itself: + */ +struct lock_class { + /* + * class-hash: + */ + struct list_head hash_entry; + + /* + * global list of all lock-classes: + */ + struct list_head lock_entry; + + struct lockdep_subclass_key *key; + unsigned int subclass; + unsigned int dep_gen_id; + + /* + * IRQ/softirq usage tracking bits: + */ + unsigned long usage_mask; + struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; + + /* + * These fields represent a directed graph of lock dependencies, + * to every node we attach a list of "forward" and a list of + * "backward" graph nodes. + */ + struct list_head locks_after, locks_before; + + /* + * Generation counter, when doing certain classes of graph walking, + * to ensure that we check one node only once: + */ + unsigned int version; + + /* + * Statistics counter: + */ + unsigned long ops; + + const char *name; + int name_version; + +#ifdef CONFIG_LOCK_STAT + unsigned long contention_point[LOCKSTAT_POINTS]; + unsigned long contending_point[LOCKSTAT_POINTS]; +#endif +}; + +#ifdef CONFIG_LOCK_STAT +struct lock_time { + s64 min; + s64 max; + s64 total; + unsigned long nr; +}; + +enum bounce_type { + bounce_acquired_write, + bounce_acquired_read, + bounce_contended_write, + bounce_contended_read, + nr_bounce_types, + + bounce_acquired = bounce_acquired_write, + bounce_contended = bounce_contended_write, +}; + +struct lock_class_stats { + unsigned long contention_point[4]; + unsigned long contending_point[4]; + struct lock_time read_waittime; + struct lock_time write_waittime; + struct lock_time read_holdtime; + struct lock_time write_holdtime; + unsigned long bounces[nr_bounce_types]; +}; + +struct lock_class_stats lock_stats(struct lock_class *class); +void clear_lock_stats(struct lock_class *class); +#endif + +/* + * Map the lock object (the lock instance) to the lock-class object. + * This is embedded into specific lock instances: + */ +struct lockdep_map { + struct lock_class_key *key; + struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES]; + const char *name; +#ifdef CONFIG_LOCK_STAT + int cpu; + unsigned long ip; +#endif +}; + +static inline void lockdep_copy_map(struct lockdep_map *to, + struct lockdep_map *from) +{ + int i; + + *to = *from; + /* + * Since the class cache can be modified concurrently we could observe + * half pointers (64bit arch using 32bit copy insns). Therefore clear + * the caches and take the performance hit. + * + * XXX it doesn't work well with lockdep_set_class_and_subclass(), since + * that relies on cache abuse. + */ + for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) + to->class_cache[i] = NULL; +} + +/* + * Every lock has a list of other locks that were taken after it. + * We only grow the list, never remove from it: + */ +struct lock_list { + struct list_head entry; + struct lock_class *class; + struct stack_trace trace; + int distance; + + /* + * The parent field is used to implement breadth-first search, and the + * bit 0 is reused to indicate if the lock has been accessed in BFS. + */ + struct lock_list *parent; +}; + +/* + * We record lock dependency chains, so that we can cache them: + */ +struct lock_chain { + u8 irq_context; + u8 depth; + u16 base; + struct list_head entry; + u64 chain_key; +}; + +#define MAX_LOCKDEP_KEYS_BITS 13 +/* + * Subtract one because we offset hlock->class_idx by 1 in order + * to make 0 mean no class. This avoids overflowing the class_idx + * bitfield and hitting the BUG in hlock_class(). + */ +#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) + +struct held_lock { + /* + * One-way hash of the dependency chain up to this point. We + * hash the hashes step by step as the dependency chain grows. + * + * We use it for dependency-caching and we skip detection + * passes and dependency-updates if there is a cache-hit, so + * it is absolutely critical for 100% coverage of the validator + * to have a unique key value for every unique dependency path + * that can occur in the system, to make a unique hash value + * as likely as possible - hence the 64-bit width. + * + * The task struct holds the current hash value (initialized + * with zero), here we store the previous hash value: + */ + u64 prev_chain_key; + unsigned long acquire_ip; + struct lockdep_map *instance; + struct lockdep_map *nest_lock; +#ifdef CONFIG_LOCK_STAT + u64 waittime_stamp; + u64 holdtime_stamp; +#endif + unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; + /* + * The lock-stack is unified in that the lock chains of interrupt + * contexts nest ontop of process context chains, but we 'separate' + * the hashes by starting with 0 if we cross into an interrupt + * context, and we also keep do not add cross-context lock + * dependencies - the lock usage graph walking covers that area + * anyway, and we'd just unnecessarily increase the number of + * dependencies otherwise. [Note: hardirq and softirq contexts + * are separated from each other too.] + * + * The following field is used to detect when we cross into an + * interrupt context: + */ + unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ + unsigned int trylock:1; /* 16 bits */ + + unsigned int read:2; /* see lock_acquire() comment */ + unsigned int check:1; /* see lock_acquire() comment */ + unsigned int hardirqs_off:1; + unsigned int references:12; /* 32 bits */ +}; + +/* + * Initialization, self-test and debugging-output methods: + */ +extern void lockdep_init(void); +extern void lockdep_info(void); +extern void lockdep_reset(void); +extern void lockdep_reset_lock(struct lockdep_map *lock); +extern void lockdep_free_key_range(void *start, unsigned long size); +extern asmlinkage void lockdep_sys_exit(void); + +extern void lockdep_off(void); +extern void lockdep_on(void); + +/* + * These methods are used by specific locking variants (spinlocks, + * rwlocks, mutexes and rwsems) to pass init/acquire/release events + * to lockdep: + */ + +extern void lockdep_init_map(struct lockdep_map *lock, const char *name, + struct lock_class_key *key, int subclass); + +/* + * To initialize a lockdep_map statically use this macro. + * Note that _name must not be NULL. + */ +#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ + { .name = (_name), .key = (void *)(_key), } + +/* + * Reinitialize a lock key - for cases where there is special locking or + * special initialization of locks so that the validator gets the scope + * of dependencies wrong: they are either too broad (they need a class-split) + * or they are too narrow (they suffer from a false class-split): + */ +#define lockdep_set_class(lock, key) \ + lockdep_init_map(&(lock)->dep_map, #key, key, 0) +#define lockdep_set_class_and_name(lock, key, name) \ + lockdep_init_map(&(lock)->dep_map, name, key, 0) +#define lockdep_set_class_and_subclass(lock, key, sub) \ + lockdep_init_map(&(lock)->dep_map, #key, key, sub) +#define lockdep_set_subclass(lock, sub) \ + lockdep_init_map(&(lock)->dep_map, #lock, \ + (lock)->dep_map.key, sub) + +#define lockdep_set_novalidate_class(lock) \ + lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock) +/* + * Compare locking classes + */ +#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) + +static inline int lockdep_match_key(struct lockdep_map *lock, + struct lock_class_key *key) +{ + return lock->key == key; +} + +/* + * Acquire a lock. + * + * Values for "read": + * + * 0: exclusive (write) acquire + * 1: read-acquire (no recursion allowed) + * 2: read-acquire with same-instance recursion allowed + * + * Values for check: + * + * 0: simple checks (freeing, held-at-exit-time, etc.) + * 1: full validation + */ +extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, + int trylock, int read, int check, + struct lockdep_map *nest_lock, unsigned long ip); + +extern void lock_release(struct lockdep_map *lock, int nested, + unsigned long ip); + +#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) + +extern int lock_is_held(struct lockdep_map *lock); + +extern void lock_set_class(struct lockdep_map *lock, const char *name, + struct lock_class_key *key, unsigned int subclass, + unsigned long ip); + +static inline void lock_set_subclass(struct lockdep_map *lock, + unsigned int subclass, unsigned long ip) +{ + lock_set_class(lock, lock->name, lock->key, subclass, ip); +} + +extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask); +extern void lockdep_clear_current_reclaim_state(void); +extern void lockdep_trace_alloc(gfp_t mask); + +# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0, + +#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) + +#define lockdep_assert_held(l) do { \ + WARN_ON(debug_locks && !lockdep_is_held(l)); \ + } while (0) + +#define lockdep_assert_held_once(l) do { \ + WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ + } while (0) + +#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) + +#else /* !CONFIG_LOCKDEP */ + +static inline void lockdep_off(void) +{ +} + +static inline void lockdep_on(void) +{ +} + +# define lock_acquire(l, s, t, r, c, n, i) do { } while (0) +# define lock_release(l, n, i) do { } while (0) +# define lock_set_class(l, n, k, s, i) do { } while (0) +# define lock_set_subclass(l, s, i) do { } while (0) +# define lockdep_set_current_reclaim_state(g) do { } while (0) +# define lockdep_clear_current_reclaim_state() do { } while (0) +# define lockdep_trace_alloc(g) do { } while (0) +# define lockdep_init() do { } while (0) +# define lockdep_info() do { } while (0) +# define lockdep_init_map(lock, name, key, sub) \ + do { (void)(name); (void)(key); } while (0) +# define lockdep_set_class(lock, key) do { (void)(key); } while (0) +# define lockdep_set_class_and_name(lock, key, name) \ + do { (void)(key); (void)(name); } while (0) +#define lockdep_set_class_and_subclass(lock, key, sub) \ + do { (void)(key); } while (0) +#define lockdep_set_subclass(lock, sub) do { } while (0) + +#define lockdep_set_novalidate_class(lock) do { } while (0) + +/* + * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP + * case since the result is not well defined and the caller should rather + * #ifdef the call himself. + */ + +# define INIT_LOCKDEP +# define lockdep_reset() do { debug_locks = 1; } while (0) +# define lockdep_free_key_range(start, size) do { } while (0) +# define lockdep_sys_exit() do { } while (0) +/* + * The class key takes no space if lockdep is disabled: + */ +struct lock_class_key { }; + +#define lockdep_depth(tsk) (0) + +#define lockdep_assert_held(l) do { (void)(l); } while (0) +#define lockdep_assert_held_once(l) do { (void)(l); } while (0) + +#define lockdep_recursing(tsk) (0) + +#endif /* !LOCKDEP */ + +#ifdef CONFIG_LOCK_STAT + +extern void lock_contended(struct lockdep_map *lock, unsigned long ip); +extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); + +#define LOCK_CONTENDED(_lock, try, lock) \ +do { \ + if (!try(_lock)) { \ + lock_contended(&(_lock)->dep_map, _RET_IP_); \ + lock(_lock); \ + } \ + lock_acquired(&(_lock)->dep_map, _RET_IP_); \ +} while (0) + +#else /* CONFIG_LOCK_STAT */ + +#define lock_contended(lockdep_map, ip) do {} while (0) +#define lock_acquired(lockdep_map, ip) do {} while (0) + +#define LOCK_CONTENDED(_lock, try, lock) \ + lock(_lock) + +#endif /* CONFIG_LOCK_STAT */ + +#ifdef CONFIG_LOCKDEP + +/* + * On lockdep we dont want the hand-coded irq-enable of + * _raw_*_lock_flags() code, because lockdep assumes + * that interrupts are not re-enabled during lock-acquire: + */ +#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ + LOCK_CONTENDED((_lock), (try), (lock)) + +#else /* CONFIG_LOCKDEP */ + +#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ + lockfl((_lock), (flags)) + +#endif /* CONFIG_LOCKDEP */ + +#ifdef CONFIG_TRACE_IRQFLAGS +extern void print_irqtrace_events(struct task_struct *curr); +#else +static inline void print_irqtrace_events(struct task_struct *curr) +{ +} +#endif + +/* + * For trivial one-depth nesting of a lock-class, the following + * global define can be used. (Subsystems with multiple levels + * of nesting should define their own lock-nesting subclasses.) + */ +#define SINGLE_DEPTH_NESTING 1 + +/* + * Map the dependency ops to NOP or to real lockdep ops, depending + * on the per lock-class debug mode: + */ + +#define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) +#define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) +#define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) + +#define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define spin_release(l, n, i) lock_release(l, n, i) + +#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) +#define rwlock_release(l, n, i) lock_release(l, n, i) + +#define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) +#define seqcount_release(l, n, i) lock_release(l, n, i) + +#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define mutex_release(l, n, i) lock_release(l, n, i) + +#define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) +#define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) +#define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i) +#define rwsem_release(l, n, i) lock_release(l, n, i) + +#define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_) +#define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_) +#define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_) +#define lock_map_release(l) lock_release(l, 1, _THIS_IP_) + +#ifdef CONFIG_PROVE_LOCKING +# define might_lock(lock) \ +do { \ + typecheck(struct lockdep_map *, &(lock)->dep_map); \ + lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \ + lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ +} while (0) +# define might_lock_read(lock) \ +do { \ + typecheck(struct lockdep_map *, &(lock)->dep_map); \ + lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \ + lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ +} while (0) +#else +# define might_lock(lock) do { } while (0) +# define might_lock_read(lock) do { } while (0) +#endif + +#ifdef CONFIG_LOCKDEP +void lockdep_rcu_suspicious(const char *file, const int line, const char *s); +#else +static inline void +lockdep_rcu_suspicious(const char *file, const int line, const char *s) +{ +} +#endif + +#endif /* __LINUX_LOCKDEP_H */ |