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/*

 * 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;

#ifdef CONFIG_LOCKDEP

#include <linux/linkage.h>

#include <linux/list.h>

#include <linux/debug_locks.h>

#include <linux/stacktrace.h>

/*

 * Lock-class usage-state bits:

 */

enum lock_usage_bit

{

        LOCK_USED = 0,

        LOCK_USED_IN_HARDIRQ,

        LOCK_USED_IN_SOFTIRQ,

        LOCK_ENABLED_SOFTIRQS,

        LOCK_ENABLED_HARDIRQS,

        LOCK_USED_IN_HARDIRQ_READ,

        LOCK_USED_IN_SOFTIRQ_READ,

        LOCK_ENABLED_SOFTIRQS_READ,

        LOCK_ENABLED_HARDIRQS_READ,

        LOCK_USAGE_STATES

};

/*

 * Usage-state bitmasks:

 */

#define LOCKF_USED                      (1 << LOCK_USED)

#define LOCKF_USED_IN_HARDIRQ           (1 << LOCK_USED_IN_HARDIRQ)

#define LOCKF_USED_IN_SOFTIRQ           (1 << LOCK_USED_IN_SOFTIRQ)

#define LOCKF_ENABLED_HARDIRQS          (1 << LOCK_ENABLED_HARDIRQS)

#define LOCKF_ENABLED_SOFTIRQS          (1 << LOCK_ENABLED_SOFTIRQS)

#define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS)

#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)

#define LOCKF_USED_IN_HARDIRQ_READ      (1 << LOCK_USED_IN_HARDIRQ_READ)

#define LOCKF_USED_IN_SOFTIRQ_READ      (1 << LOCK_USED_IN_SOFTIRQ_READ)

#define LOCKF_ENABLED_HARDIRQS_READ     (1 << LOCK_ENABLED_HARDIRQS_READ)

#define LOCKF_ENABLED_SOFTIRQS_READ     (1 << LOCK_ENABLED_SOFTIRQS_READ)

#define LOCKF_ENABLED_IRQS_READ \

                (LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ)

#define LOCKF_USED_IN_IRQ_READ \

                (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)

#define MAX_LOCKDEP_SUBCLASSES          8UL

/*

 * 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];

};

/*

 * 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;

        /*

         * IRQ/softirq usage tracking bits:

         */

        unsigned long                   usage_mask;

        struct stack_trace              usage_traces[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[4];

#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];

        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;

        const char                      *name;

#ifdef CONFIG_LOCK_STAT

        int                             cpu;

#endif

};

/*

 * 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;

};

/*

 * We record lock dependency chains, so that we can cache them:

 */

struct lock_chain {

        struct list_head                entry;

        u64                             chain_key;

};

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;

        struct lock_class               *class;

        unsigned long                   acquire_ip;

        struct lockdep_map              *instance;

#ifdef CONFIG_LOCK_STAT

        u64                             waittime_stamp;

        u64                             holdtime_stamp;

#endif

        /*

         * 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:

         */

        int                             irq_context;

        int                             trylock;

        int                             read;

        int                             check;

        int                             hardirqs_off;

};

/*

 * 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)

/*

 * 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), }

/*

 * 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, unsigned long ip);

extern void lock_release(struct lockdep_map *lock, int nested,

                         unsigned long ip);

# define INIT_LOCKDEP                           .lockdep_recursion = 0,

#define lockdep_depth(tsk)      (debug_locks ? (tsk)->lockdep_depth : 0)

#else /* !LOCKDEP */

static inline void lockdep_off(void)

{

}

static inline void lockdep_on(void)

{

}

# define lock_acquire(l, s, t, r, c, i)         do { } while (0)

# define lock_release(l, n, i)                  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)(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); } 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 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)

#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);

#define LOCK_CONTENDED(_lock, try, lock)                        \

do {                                                            \

        if (!try(_lock)) {                                      \

                lock_contended(&(_lock)->dep_map, _RET_IP_);    \

                lock(_lock);                                    \

        }                                                       \

        lock_acquired(&(_lock)->dep_map);                       \

} while (0)

#else /* CONFIG_LOCK_STAT */

#define lock_contended(lockdep_map, ip) do {} while (0)

#define lock_acquired(lockdep_map) do {} while (0)

#define LOCK_CONTENDED(_lock, try, lock) \

        lock(_lock)

#endif /* CONFIG_LOCK_STAT */

#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)

extern void early_init_irq_lock_class(void);

#else

static inline void early_init_irq_lock_class(void)

{

}

#endif

#ifdef CONFIG_TRACE_IRQFLAGS

extern void early_boot_irqs_off(void);

extern void early_boot_irqs_on(void);

extern void print_irqtrace_events(struct task_struct *curr);

#else

static inline void early_boot_irqs_off(void)

{

}

static inline void early_boot_irqs_on(void)

{

}

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_DEBUG_LOCK_ALLOC

# ifdef CONFIG_PROVE_LOCKING

#  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 2, i)

# else

#  define spin_acquire(l, s, t, i)              lock_acquire(l, s, t, 0, 1, i)

# endif

# define spin_release(l, n, i)                  lock_release(l, n, i)

#else

# define spin_acquire(l, s, t, i)               do { } while (0)

# define spin_release(l, n, i)                  do { } while (0)

#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC

# ifdef CONFIG_PROVE_LOCKING

#  define rwlock_acquire(l, s, t, i)            lock_acquire(l, s, t, 0, 2, i)

#  define rwlock_acquire_read(l, s, t, i)       lock_acquire(l, s, t, 2, 2, i)

# else

#  define rwlock_acquire(l, s, t, i)            lock_acquire(l, s, t, 0, 1, i)

#  define rwlock_acquire_read(l, s, t, i)       lock_acquire(l, s, t, 2, 1, i)

# endif

# define rwlock_release(l, n, i)                lock_release(l, n, i)

#else

# define rwlock_acquire(l, s, t, i)             do { } while (0)

# define rwlock_acquire_read(l, s, t, i)        do { } while (0)

# define rwlock_release(l, n, i)                do { } while (0)

#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC

# ifdef CONFIG_PROVE_LOCKING

#  define mutex_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 2, i)

# else

#  define mutex_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 1, i)

# endif

# define mutex_release(l, n, i)                 lock_release(l, n, i)

#else

# define mutex_acquire(l, s, t, i)              do { } while (0)

# define mutex_release(l, n, i)                 do { } while (0)

#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC

# ifdef CONFIG_PROVE_LOCKING

#  define rwsem_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 2, i)

#  define rwsem_acquire_read(l, s, t, i)        lock_acquire(l, s, t, 1, 2, i)

# else

#  define rwsem_acquire(l, s, t, i)             lock_acquire(l, s, t, 0, 1, i)

#  define rwsem_acquire_read(l, s, t, i)        lock_acquire(l, s, t, 1, 1, i)

# endif

# define rwsem_release(l, n, i)                 lock_release(l, n, i)

#else

# define rwsem_acquire(l, s, t, i)              do { } while (0)

# define rwsem_acquire_read(l, s, t, i)         do { } while (0)

# define rwsem_release(l, n, i)                 do { } while (0)

#endif

#endif /* __LINUX_LOCKDEP_H */