Viewing file:  spinlock.h (3.13 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
#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_spin_relax(lock) cpu_relax()
#define _raw_read_relax(lock) cpu_relax()
#define _raw_write_relax(lock) cpu_relax()
#endif /* _ALPHA_SPINLOCK_H */
|