text: /*
   * Copyright (2004) Linus Torvalds
   *
   * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
   *
   * Copyright (2004, 2005) Ingo Molnar
   *
   * This file contains the spinlock/rwlock implementations for the
   * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
   *
   * Note that some architectures have special knowledge about the
   * stack frames of these functions in their profile_pc. If you
   * change anything significant here that could change the stack
   * frame contact the architecture maintainers.
   */
  
  #include <linux/linkage.h>
  #include <linux/preempt.h>
  #include <linux/spinlock.h>
  #include <linux/interrupt.h>
  #include <linux/debug_locks.h>
  #include <linux/module.h>
  
  int __lockfunc _spin_trylock(spinlock_t *lock)
  {
  	preempt_disable();
  	if (_raw_spin_trylock(lock)) {
  		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  		return 1;
  	}
  	
  	preempt_enable();
  	return 0;
  }
  EXPORT_SYMBOL(_spin_trylock);
  
  int __lockfunc _read_trylock(rwlock_t *lock)
  {
  	preempt_disable();
  	if (_raw_read_trylock(lock)) {
  		rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
  		return 1;
  	}
  
  	preempt_enable();
  	return 0;
  }
  EXPORT_SYMBOL(_read_trylock);
  
  int __lockfunc _write_trylock(rwlock_t *lock)
  {
  	preempt_disable();
  	if (_raw_write_trylock(lock)) {
  		rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  		return 1;
  	}
  
  	preempt_enable();
  	return 0;
  }
  EXPORT_SYMBOL(_write_trylock);
  
  /*
   * If lockdep is enabled then we use the non-preemption spin-ops
   * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
   * not re-enabled during lock-acquire (which the preempt-spin-ops do):
   */
  #if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) || \
  	defined(CONFIG_DEBUG_LOCK_ALLOC)
  
  void __lockfunc _read_lock(rwlock_t *lock)
  {
  	preempt_disable();
  	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
  }
  EXPORT_SYMBOL(_read_lock);
  
  unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	preempt_disable();
  	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	/*
  	 * On lockdep we dont want the hand-coded irq-enable of
  	 * _raw_spin_lock_flags() code, because lockdep assumes
  	 * that interrupts are not re-enabled during lock-acquire:
  	 */
  #ifdef CONFIG_LOCKDEP
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  #else
  	_raw_spin_lock_flags(lock, &flags);
  #endif
  	return flags;
  }
  EXPORT_SYMBOL(_spin_lock_irqsave);
  
  void __lockfunc _spin_lock_irq(spinlock_t *lock)
  {
  	local_irq_disable();
  	preempt_disable();
  	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  }
  EXPORT_SYMBOL(_spin_lock_irq);
  
  void __lockfunc _spin_lock_bh(spinlock_t *lock)
  {
  	local_bh_disable();
  	preempt_disable();
  	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  }
  EXPORT_SYMBOL(_spin_lock_bh);
  
  unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	preempt_disable();
  	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
  	return flags;
  }
  EXPORT_SYMBOL(_read_lock_irqsave);
  
  void __lockfunc _read_lock_irq(rwlock_t *lock)
  {
  	local_irq_disable();
  	preempt_disable();
  	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
  }
  EXPORT_SYMBOL(_read_lock_irq);
  
  void __lockfunc _read_lock_bh(rwlock_t *lock)
  {
  	local_bh_disable();
  	preempt_disable();
  	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
  }
  EXPORT_SYMBOL(_read_lock_bh);
  
  unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	preempt_disable();
  	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
  	return flags;
  }
  EXPORT_SYMBOL(_write_lock_irqsave);
  
  void __lockfunc _write_lock_irq(rwlock_t *lock)
  {
  	local_irq_disable();
  	preempt_disable();
  	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
  }
  EXPORT_SYMBOL(_write_lock_irq);
  
  void __lockfunc _write_lock_bh(rwlock_t *lock)
  {
  	local_bh_disable();
  	preempt_disable();
  	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
  }
  EXPORT_SYMBOL(_write_lock_bh);
  
  void __lockfunc _spin_lock(spinlock_t *lock)
  {
  	preempt_disable();
  	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  }
  
  EXPORT_SYMBOL(_spin_lock);
  
  void __lockfunc _write_lock(rwlock_t *lock)
  {
  	preempt_disable();
  	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
  }
  
  EXPORT_SYMBOL(_write_lock);
  
  #else /* CONFIG_PREEMPT: */
  
  /*
   * This could be a long-held lock. We both prepare to spin for a long
   * time (making _this_ CPU preemptable if possible), and we also signal
   * towards that other CPU that it should break the lock ASAP.
   *
   * (We do this in a function because inlining it would be excessive.)
   */
  
  #define BUILD_LOCK_OPS(op, locktype)					\
  void __lockfunc _##op##_lock(locktype##_t *lock)			\
  {									\
  	for (;;) {							\
  		preempt_disable();					\
  		if (likely(_raw_##op##_trylock(lock)))			\
  			break;						\
  		preempt_enable();					\
  									\
  		if (!(lock)->break_lock)				\
  			(lock)->break_lock = 1;				\
  		while (!op##_can_lock(lock) && (lock)->break_lock)	\
  			_raw_##op##_relax(&lock->raw_lock);		\
  	}								\
  	(lock)->break_lock = 0;						\
  }									\
  									\
  EXPORT_SYMBOL(_##op##_lock);						\
  									\
  unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock)	\
  {									\
  	unsigned long flags;						\
  									\
  	for (;;) {							\
  		preempt_disable();					\
  		local_irq_save(flags);					\
  		if (likely(_raw_##op##_trylock(lock)))			\
  			break;						\
  		local_irq_restore(flags);				\
  		preempt_enable();					\
  									\
  		if (!(lock)->break_lock)				\
  			(lock)->break_lock = 1;				\
  		while (!op##_can_lock(lock) && (lock)->break_lock)	\
  			_raw_##op##_relax(&lock->raw_lock);		\
  	}								\
  	(lock)->break_lock = 0;						\
  	return flags;							\
  }									\
  									\
  EXPORT_SYMBOL(_##op##_lock_irqsave);					\
  									\
  void __lockfunc _##op##_lock_irq(locktype##_t *lock)			\
  {									\
  	_##op##_lock_irqsave(lock);					\
  }									\
  									\
  EXPORT_SYMBOL(_##op##_lock_irq);					\
  									\
  void __lockfunc _##op##_lock_bh(locktype##_t *lock)			\
  {									\
  	unsigned long flags;						\
  									\
  	/*							*/	\
  	/* Careful: we must exclude softirqs too, hence the	*/	\
  	/* irq-disabling. We use the generic preemption-aware	*/	\
  	/* function:						*/	\
  	/**/								\
  	flags = _##op##_lock_irqsave(lock);				\
  	local_bh_disable();						\
  	local_irq_restore(flags);					\
  }									\
  									\
  EXPORT_SYMBOL(_##op##_lock_bh)
  
  /*
   * Build preemption-friendly versions of the following
   * lock-spinning functions:
   *
   *         _[spin|read|write]_lock()
   *         _[spin|read|write]_lock_irq()
   *         _[spin|read|write]_lock_irqsave()
   *         _[spin|read|write]_lock_bh()
   */
  BUILD_LOCK_OPS(spin, spinlock);
  BUILD_LOCK_OPS(read, rwlock);
  BUILD_LOCK_OPS(write, rwlock);
  
  #endif /* CONFIG_PREEMPT */
  
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  
  void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)
  {
  	preempt_disable();
  	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  }
  
  EXPORT_SYMBOL(_spin_lock_nested);
  unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	preempt_disable();
  	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
  	/*
  	 * On lockdep we dont want the hand-coded irq-enable of
  	 * _raw_spin_lock_flags() code, because lockdep assumes
  	 * that interrupts are not re-enabled during lock-acquire:
  	 */
  #ifdef CONFIG_LOCKDEP
  	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
  #else
  	_raw_spin_lock_flags(lock, &flags);
  #endif
  	return flags;
  }
  
  EXPORT_SYMBOL(_spin_lock_irqsave_nested);
  
  #endif
  
  void __lockfunc _spin_unlock(spinlock_t *lock)
  {
  	spin_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_spin_unlock(lock);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_spin_unlock);
  
  void __lockfunc _write_unlock(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_write_unlock(lock);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_write_unlock);
  
  void __lockfunc _read_unlock(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_read_unlock(lock);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_read_unlock);
  
  void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
  {
  	spin_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_spin_unlock(lock);
  	local_irq_restore(flags);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_spin_unlock_irqrestore);
  
  void __lockfunc _spin_unlock_irq(spinlock_t *lock)
  {
  	spin_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_spin_unlock(lock);
  	local_irq_enable();
  	preempt_enable();
  }
  EXPORT_SYMBOL(_spin_unlock_irq);
  
  void __lockfunc _spin_unlock_bh(spinlock_t *lock)
  {
  	spin_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_spin_unlock(lock);
  	preempt_enable_no_resched();
  	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  }
  EXPORT_SYMBOL(_spin_unlock_bh);
  
  void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_read_unlock(lock);
  	local_irq_restore(flags);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_read_unlock_irqrestore);
  
  void __lockfunc _read_unlock_irq(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_read_unlock(lock);
  	local_irq_enable();
  	preempt_enable();
  }
  EXPORT_SYMBOL(_read_unlock_irq);
  
  void __lockfunc _read_unlock_bh(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_read_unlock(lock);
  	preempt_enable_no_resched();
  	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  }
  EXPORT_SYMBOL(_read_unlock_bh);
  
  void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_write_unlock(lock);
  	local_irq_restore(flags);
  	preempt_enable();
  }
  EXPORT_SYMBOL(_write_unlock_irqrestore);
  
  void __lockfunc _write_unlock_irq(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_write_unlock(lock);
  	local_irq_enable();
  	preempt_enable();
  }
  EXPORT_SYMBOL(_write_unlock_irq);
  
  void __lockfunc _write_unlock_bh(rwlock_t *lock)
  {
  	rwlock_release(&lock->dep_map, 1, _RET_IP_);
  	_raw_write_unlock(lock);
  	preempt_enable_no_resched();
  	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  }
  EXPORT_SYMBOL(_write_unlock_bh);
  
  int __lockfunc _spin_trylock_bh(spinlock_t *lock)
  {
  	local_bh_disable();
  	preempt_disable();
  	if (_raw_spin_trylock(lock)) {
  		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  		return 1;
  	}
  
  	preempt_enable_no_resched();
  	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  	return 0;
  }
  EXPORT_SYMBOL(_spin_trylock_bh);
  
  int in_lock_functions(unsigned long addr)
  {
  	/* Linker adds these: start and end of __lockfunc functions */
  	extern char __lock_text_start[], __lock_text_end[];
  
  	return addr >= (unsigned long)__lock_text_start
  	&& addr < (unsigned long)__lock_text_end;
  }
  EXPORT_SYMBOL(in_lock_functions);
  