/*
   * 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;
  
  	/*
  	 * 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

  };
  
  /*
   * 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);

  #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)	WARN_ON(debug_locks && !lockdep_is_held(l))

  #else /* !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 { } while (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_DEBUG_LOCK_ALLOC
  # ifdef CONFIG_PROVE_LOCKING

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

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

  # else

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

  #  define spin_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 1, NULL, 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, NULL, i)
  #  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 2, NULL, i)

  # else

  #  define rwlock_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
  #  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 1, NULL, 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, NULL, i)

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

  # else

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

  #  define mutex_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 1, n, 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_acquire_nest(l, s, t, n, 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, NULL, i)
  #  define rwsem_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 1, 2, NULL, i)

  # else

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

  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  # ifdef CONFIG_PROVE_LOCKING

  #  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)

  #  define lock_map_acquire_read(l)	lock_acquire(l, 0, 0, 2, 2, NULL, _THIS_IP_)

  # else

  #  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)

  #  define lock_map_acquire_read(l)	lock_acquire(l, 0, 0, 2, 1, NULL, _THIS_IP_)

  # endif

  # define lock_map_release(l)			lock_release(l, 1, _THIS_IP_)

  #else

  # define lock_map_acquire(l)			do { } while (0)

  # define lock_map_acquire_read(l)		do { } while (0)

  # define lock_map_release(l)			do { } while (0)

  #endif

  #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
  extern void lockdep_rcu_dereference(const char *file, const int line);
  #endif

  #endif /* __LINUX_LOCKDEP_H */