Edit File: lockdep.h
/* * 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/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; int name_version; const char *name; #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:2; /* see lock_acquire() comment */ unsigned int hardirqs_off:1; unsigned int references:11; /* 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 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(lock, &__lockdep_no_validate__) /* * 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: disabled * 1: simple checks (freeing, held-at-exit-time, etc.) * 2: 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); /* * Same "read" as for lock_acquire(), except -1 means any. */ extern int lock_is_held_type(struct lockdep_map *lock, int read); static inline int lock_is_held(struct lockdep_map *lock) { return lock_is_held_type(lock, -1); } #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r)) 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_exclusive(l) do { \ WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ } while (0) #define lockdep_assert_held_read(l) do { \ WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \ } 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_is_held_type(l, r) (1) #define lockdep_assert_held(l) do { (void)(l); } while (0) #define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0) #define lockdep_assert_held_read(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: */ #ifdef CONFIG_PROVE_LOCKING #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 2, n, i) #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 2, n, i) #else #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) #endif #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, 2, 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, 2, 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_PROVE_RCU void lockdep_rcu_suspicious(const char *file, const int line, const char *s); #endif #endif /* __LINUX_LOCKDEP_H */