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#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
#include <lib.h>
/*
* Your basic SMP spinlocks, allowing only a single CPU anywhere
*/
typedef struct {
volatile unsigned int slock;
} spinlock_t;
#define SPINLOCK_MAGIC 0xdead4ead
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 }
#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
/*
* 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 spin_is_locked(x) (*(volatile signed char *)(&(x)->slock) <= 0)
#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
#define spin_lock_string \
"1:\n" \
LOCK \
"decb %0\n\t" \
"jns 3f\n" \
"2:\t" \
"rep;nop\n\t" \
"cmpb $0,%0\n\t" \
"jle 2b\n\t" \
"jmp 1b\n" \
"3:\n\t"
#define spin_lock_string_flags \
"1:\n" \
LOCK \
"decb %0\n\t" \
"jns 4f\n\t" \
"2:\t" \
"testl $0x200, %1\n\t" \
"jz 3f\n\t" \
"#sti\n\t" \
"3:\t" \
"rep;nop\n\t" \
"cmpb $0, %0\n\t" \
"jle 3b\n\t" \
"#cli\n\t" \
"jmp 1b\n" \
"4:\n\t"
/*
* This works. Despite all the confusion.
* (except on PPro SMP or if we are using OOSTORE)
* (PPro errata 66, 92)
*/
#define spin_unlock_string \
"xchgb %b0, %1" \
:"=q" (oldval), "=m" (lock->slock) \
:"0" (oldval) : "memory"
static inline void _raw_spin_unlock(spinlock_t *lock)
{
char oldval = 1;
__asm__ __volatile__(
spin_unlock_string
);
}
static inline int _raw_spin_trylock(spinlock_t *lock)
{
char oldval;
__asm__ __volatile__(
"xchgb %b0,%1\n"
:"=q" (oldval), "=m" (lock->slock)
:"0" (0) : "memory");
return oldval > 0;
}
static inline void _raw_spin_lock(spinlock_t *lock)
{
__asm__ __volatile__(
spin_lock_string
:"=m" (lock->slock) : : "memory");
}
static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
{
__asm__ __volatile__(
spin_lock_string_flags
:"=m" (lock->slock) : "r" (flags) : "memory");
}
#define _spin_trylock(lock) ({_raw_spin_trylock(lock) ? \
1 : ({ 0;});})
#define _spin_lock(lock) \
do { \
_raw_spin_lock(lock); \
} while(0)
#define _spin_unlock(lock) \
do { \
_raw_spin_unlock(lock); \
} while (0)
#define spin_lock(lock) _spin_lock(lock)
#define spin_unlock(lock) _spin_unlock(lock)
#define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED
#endif
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