Logo Search packages:      
Sourcecode: linux version File versions  Download package

spinlock.h

#ifndef _ALPHA_SPINLOCK_H
#define _ALPHA_SPINLOCK_H

#include <asm/system.h>
#include <linux/kernel.h>
#include <asm/current.h>

/*
 * Simple spin lock operations.  There are two variants, one clears IRQ's
 * on the local processor, one does not.
 *
 * We make no fairness assumptions. They have a cost.
 */

#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#define __raw_spin_is_locked(x)     ((x)->lock != 0)
#define __raw_spin_unlock_wait(x) \
            do { cpu_relax(); } while ((x)->lock)

static inline void __raw_spin_unlock(raw_spinlock_t * lock)
{
      mb();
      lock->lock = 0;
}

static inline void __raw_spin_lock(raw_spinlock_t * lock)
{
      long tmp;

      __asm__ __volatile__(
      "1:   ldl_l %0,%1\n"
      "     bne   %0,2f\n"
      "     lda   %0,1\n"
      "     stl_c %0,%1\n"
      "     beq   %0,2f\n"
      "     mb\n"
      ".subsection 2\n"
      "2:   ldl   %0,%1\n"
      "     bne   %0,2b\n"
      "     br    1b\n"
      ".previous"
      : "=&r" (tmp), "=m" (lock->lock)
      : "m"(lock->lock) : "memory");
}

static inline int __raw_spin_trylock(raw_spinlock_t *lock)
{
      return !test_and_set_bit(0, &lock->lock);
}

/***********************************************************/

static inline int __raw_read_can_lock(raw_rwlock_t *lock)
{
      return (lock->lock & 1) == 0;
}

static inline int __raw_write_can_lock(raw_rwlock_t *lock)
{
      return lock->lock == 0;
}

static inline void __raw_read_lock(raw_rwlock_t *lock)
{
      long regx;

      __asm__ __volatile__(
      "1:   ldl_l %1,%0\n"
      "     blbs  %1,6f\n"
      "     subl  %1,2,%1\n"
      "     stl_c %1,%0\n"
      "     beq   %1,6f\n"
      "     mb\n"
      ".subsection 2\n"
      "6:   ldl   %1,%0\n"
      "     blbs  %1,6b\n"
      "     br    1b\n"
      ".previous"
      : "=m" (*lock), "=&r" (regx)
      : "m" (*lock) : "memory");
}

static inline void __raw_write_lock(raw_rwlock_t *lock)
{
      long regx;

      __asm__ __volatile__(
      "1:   ldl_l %1,%0\n"
      "     bne   %1,6f\n"
      "     lda   %1,1\n"
      "     stl_c %1,%0\n"
      "     beq   %1,6f\n"
      "     mb\n"
      ".subsection 2\n"
      "6:   ldl   %1,%0\n"
      "     bne   %1,6b\n"
      "     br    1b\n"
      ".previous"
      : "=m" (*lock), "=&r" (regx)
      : "m" (*lock) : "memory");
}

static inline int __raw_read_trylock(raw_rwlock_t * lock)
{
      long regx;
      int success;

      __asm__ __volatile__(
      "1:   ldl_l %1,%0\n"
      "     lda   %2,0\n"
      "     blbs  %1,2f\n"
      "     subl  %1,2,%2\n"
      "     stl_c %2,%0\n"
      "     beq   %2,6f\n"
      "2:   mb\n"
      ".subsection 2\n"
      "6:   br    1b\n"
      ".previous"
      : "=m" (*lock), "=&r" (regx), "=&r" (success)
      : "m" (*lock) : "memory");

      return success;
}

static inline int __raw_write_trylock(raw_rwlock_t * lock)
{
      long regx;
      int success;

      __asm__ __volatile__(
      "1:   ldl_l %1,%0\n"
      "     lda   %2,0\n"
      "     bne   %1,2f\n"
      "     lda   %2,1\n"
      "     stl_c %2,%0\n"
      "     beq   %2,6f\n"
      "2:   mb\n"
      ".subsection 2\n"
      "6:   br    1b\n"
      ".previous"
      : "=m" (*lock), "=&r" (regx), "=&r" (success)
      : "m" (*lock) : "memory");

      return success;
}

static inline void __raw_read_unlock(raw_rwlock_t * lock)
{
      long regx;
      __asm__ __volatile__(
      "     mb\n"
      "1:   ldl_l %1,%0\n"
      "     addl  %1,2,%1\n"
      "     stl_c %1,%0\n"
      "     beq   %1,6f\n"
      ".subsection 2\n"
      "6:   br    1b\n"
      ".previous"
      : "=m" (*lock), "=&r" (regx)
      : "m" (*lock) : "memory");
}

static inline void __raw_write_unlock(raw_rwlock_t * lock)
{
      mb();
      lock->lock = 0;
}

#define __raw_read_lock_flags(lock, flags) __raw_read_lock(lock)
#define __raw_write_lock_flags(lock, flags) __raw_write_lock(lock)

#define _raw_spin_relax(lock) cpu_relax()
#define _raw_read_relax(lock) cpu_relax()
#define _raw_write_relax(lock)      cpu_relax()

#endif /* _ALPHA_SPINLOCK_H */

Generated by  Doxygen 1.6.0   Back to index