/*
   * Copyright 2005, Red Hat, Inc., Ingo Molnar
   * Released under the General Public License (GPL).
   *
   * This file contains the spinlock/rwlock implementations for
   * DEBUG_SPINLOCK.
   */

  #include <linux/spinlock.h>

  #include <linux/nmi.h>

  #include <linux/interrupt.h>

  #include <linux/debug_locks.h>

  #include <linux/delay.h>

  #include <linux/export.h>

  void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  			  struct lock_class_key *key)

  {
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  	/*
  	 * Make sure we are not reinitializing a held lock:
  	 */
  	debug_check_no_locks_freed((void *)lock, sizeof(*lock));

  	lockdep_init_map(&lock->dep_map, name, key, 0);

  #endif

  	lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;

  	lock->magic = SPINLOCK_MAGIC;
  	lock->owner = SPINLOCK_OWNER_INIT;
  	lock->owner_cpu = -1;
  }

  EXPORT_SYMBOL(__raw_spin_lock_init);

  
  void __rwlock_init(rwlock_t *lock, const char *name,
  		   struct lock_class_key *key)
  {
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  	/*
  	 * Make sure we are not reinitializing a held lock:
  	 */
  	debug_check_no_locks_freed((void *)lock, sizeof(*lock));

  	lockdep_init_map(&lock->dep_map, name, key, 0);

  #endif

  	lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;

  	lock->magic = RWLOCK_MAGIC;
  	lock->owner = SPINLOCK_OWNER_INIT;
  	lock->owner_cpu = -1;
  }
  
  EXPORT_SYMBOL(__rwlock_init);

  static void spin_dump(raw_spinlock_t *lock, const char *msg)

  {

  	struct task_struct *owner = NULL;

  	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
  		owner = lock->owner;
  	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d
  ",
  		msg, raw_smp_processor_id(),

  		current->comm, task_pid_nr(current));

  	printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "

  			".owner_cpu: %d
  ",
  		lock, lock->magic,
  		owner ? owner->comm : "<none>",

  		owner ? task_pid_nr(owner) : -1,

  		lock->owner_cpu);
  	dump_stack();

  }

  static void spin_bug(raw_spinlock_t *lock, const char *msg)
  {
  	if (!debug_locks_off())
  		return;
  
  	spin_dump(lock, msg);
  }

  #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)

  static inline void

  debug_spin_lock_before(raw_spinlock_t *lock)

  {
  	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
  	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
  	SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
  							lock, "cpu recursion");
  }

  static inline void debug_spin_lock_after(raw_spinlock_t *lock)

  {
  	lock->owner_cpu = raw_smp_processor_id();
  	lock->owner = current;
  }

  static inline void debug_spin_unlock(raw_spinlock_t *lock)

  {
  	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");

  	SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");

  	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
  	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
  							lock, "wrong CPU");
  	lock->owner = SPINLOCK_OWNER_INIT;
  	lock->owner_cpu = -1;
  }

  static void __spin_lock_debug(raw_spinlock_t *lock)

  {

  	u64 i;

  	u64 loops = loops_per_jiffy * HZ;

  
  	for (i = 0; i < loops; i++) {
  		if (arch_spin_trylock(&lock->raw_lock))
  			return;
  		__delay(1);
  	}
  	/* lockup suspected: */
  	spin_dump(lock, "lockup suspected");

  #ifdef CONFIG_SMP

  	trigger_all_cpu_backtrace();

  #endif

  
  	/*
  	 * The trylock above was causing a livelock.  Give the lower level arch
  	 * specific lock code a chance to acquire the lock. We have already
  	 * printed a warning/backtrace at this point. The non-debug arch
  	 * specific code might actually succeed in acquiring the lock.  If it is
  	 * not successful, the end-result is the same - there is no forward
  	 * progress.
  	 */
  	arch_spin_lock(&lock->raw_lock);

  }

  void do_raw_spin_lock(raw_spinlock_t *lock)

  {
  	debug_spin_lock_before(lock);

  	if (unlikely(!arch_spin_trylock(&lock->raw_lock)))

  		__spin_lock_debug(lock);
  	debug_spin_lock_after(lock);
  }

  int do_raw_spin_trylock(raw_spinlock_t *lock)

  {

  	int ret = arch_spin_trylock(&lock->raw_lock);

  
  	if (ret)
  		debug_spin_lock_after(lock);
  #ifndef CONFIG_SMP
  	/*
  	 * Must not happen on UP:
  	 */
  	SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
  #endif
  	return ret;
  }

  void do_raw_spin_unlock(raw_spinlock_t *lock)

  {
  	debug_spin_unlock(lock);

  	arch_spin_unlock(&lock->raw_lock);

  }
  
  static void rwlock_bug(rwlock_t *lock, const char *msg)
  {

  	if (!debug_locks_off())
  		return;
  
  	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p
  ",
  		msg, raw_smp_processor_id(), current->comm,

  		task_pid_nr(current), lock);

  	dump_stack();

  }
  
  #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)

  #if 0		/* __write_lock_debug() can lock up - maybe this can too? */

  static void __read_lock_debug(rwlock_t *lock)
  {

  	u64 i;

  	u64 loops = loops_per_jiffy * HZ;
  	int print_once = 1;

  
  	for (;;) {

  		for (i = 0; i < loops; i++) {

  			if (arch_read_trylock(&lock->raw_lock))

  				return;

  			__delay(1);

  		}
  		/* lockup suspected: */
  		if (print_once) {
  			print_once = 0;

  			printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
  					"%s/%d, %p
  ",

  				raw_smp_processor_id(), current->comm,
  				current->pid, lock);

  			dump_stack();
  		}
  	}
  }

  #endif

  void do_raw_read_lock(rwlock_t *lock)

  {
  	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

  	arch_read_lock(&lock->raw_lock);

  }

  int do_raw_read_trylock(rwlock_t *lock)

  {

  	int ret = arch_read_trylock(&lock->raw_lock);

  
  #ifndef CONFIG_SMP
  	/*
  	 * Must not happen on UP:
  	 */
  	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
  #endif
  	return ret;
  }

  void do_raw_read_unlock(rwlock_t *lock)

  {
  	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

  	arch_read_unlock(&lock->raw_lock);

  }
  
  static inline void debug_write_lock_before(rwlock_t *lock)
  {
  	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
  	RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
  	RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
  							lock, "cpu recursion");
  }
  
  static inline void debug_write_lock_after(rwlock_t *lock)
  {
  	lock->owner_cpu = raw_smp_processor_id();
  	lock->owner = current;
  }
  
  static inline void debug_write_unlock(rwlock_t *lock)
  {
  	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
  	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
  	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
  							lock, "wrong CPU");
  	lock->owner = SPINLOCK_OWNER_INIT;
  	lock->owner_cpu = -1;
  }

  #if 0		/* This can cause lockups */

  static void __write_lock_debug(rwlock_t *lock)
  {

  	u64 i;

  	u64 loops = loops_per_jiffy * HZ;
  	int print_once = 1;

  
  	for (;;) {

  		for (i = 0; i < loops; i++) {

  			if (arch_write_trylock(&lock->raw_lock))

  				return;

  			__delay(1);

  		}
  		/* lockup suspected: */
  		if (print_once) {
  			print_once = 0;

  			printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
  					"%s/%d, %p
  ",

  				raw_smp_processor_id(), current->comm,
  				current->pid, lock);

  			dump_stack();
  		}
  	}
  }

  #endif

  void do_raw_write_lock(rwlock_t *lock)

  {
  	debug_write_lock_before(lock);

  	arch_write_lock(&lock->raw_lock);

  	debug_write_lock_after(lock);
  }

  int do_raw_write_trylock(rwlock_t *lock)

  {

  	int ret = arch_write_trylock(&lock->raw_lock);

  
  	if (ret)
  		debug_write_lock_after(lock);
  #ifndef CONFIG_SMP
  	/*
  	 * Must not happen on UP:
  	 */
  	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
  #endif
  	return ret;
  }

  void do_raw_write_unlock(rwlock_t *lock)

  {
  	debug_write_unlock(lock);

  	arch_write_unlock(&lock->raw_lock);

  }