semaphore-helper.h
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#ifndef _M68K_SEMAPHORE_HELPER_H
#define _M68K_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
#include <linux/errno.h>
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
#ifndef CONFIG_RMW_INSNS
extern spinlock_t semaphore_wake_lock;
#endif
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #1,%0\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "0" (0), "1" (sem->waking));
#endif
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #1,%0\n"
" jra %a4\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "i" (&&next), "0" (0), "1" (sem->waking));
if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
next:
#endif
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret;
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 1;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 0;
} else
atomic_inc(&sem->count);
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
#else
int tmp1, tmp2;
__asm__ __volatile__
("1: movel %1,%2\n"
" jle 2f\n"
" subql #1,%2\n"
" casl %1,%2,%3\n"
" jne 1b\n"
" moveq #0,%0\n"
"2:"
: "=d" (ret), "=d" (tmp1), "=d" (tmp2)
: "m" (sem->waking), "0" (1), "1" (sem->waking));
if (ret)
atomic_inc(&sem->count);
#endif
return ret;
}
#endif