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sh: Fix sh4a llsc-based cmpxchg()

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This fixes up a typo in the ll/sc based cmpxchg code which apparently
wasn't getting a lot of testing due to the swapped old/new pair. With
that fixed up, the ll/sc code also starts using it and provides its own
atomic_add_unless().

Signed-off-by: Aoi Shinkai <shinkoi2005@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Aoi Shinkai 2009-06-10 16:15:42 +00:00 committed by Paul Mundt
parent f168dd00a9
commit 4c7c997886
4 changed files with 31 additions and 4 deletions
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27
arch/sh/include/asm/atomic-llsc.h
View File

@ -104,4 +104,31 @@ static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
: "t");
}
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
/**
* atomic_add_unless - add unless the number is a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
int c, old;
c = atomic_read(v);
for (;;) {
if (unlikely(c == (u)))
break;
old = atomic_cmpxchg((v), c, c + (a));
if (likely(old == c))
break;
c = old;
}
return c != (u);
}
#endif /* __ASM_SH_ATOMIC_LLSC_H */

4
arch/sh/include/asm/atomic.h
View File

@ -45,7 +45,7 @@
#define atomic_inc(v) atomic_add(1,(v))
#define atomic_dec(v) atomic_sub(1,(v))
#ifndef CONFIG_GUSA_RB
#if !defined(CONFIG_GUSA_RB) && !defined(CONFIG_CPU_SH4A)
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
int ret;
@ -73,7 +73,7 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
return ret != u;
}
#endif
#endif /* !CONFIG_GUSA_RB && !CONFIG_CPU_SH4A */
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

2
arch/sh/include/asm/cmpxchg-llsc.h
View File

@ -55,7 +55,7 @@ __cmpxchg_u32(volatile int *m, unsigned long old, unsigned long new)
"mov %0, %1 \n\t"
"cmp/eq %1, %3 \n\t"
"bf 2f \n\t"
"mov %3, %0 \n\t"
"mov %4, %0 \n\t"
"2: \n\t"
"movco.l %0, @%2 \n\t"
"bf 1b \n\t"

2
arch/sh/include/asm/spinlock.h
View File

@ -26,7 +26,7 @@
#define __raw_spin_is_locked(x) ((x)->lock <= 0)
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#define __raw_spin_unlock_wait(x) \
do { cpu_relax(); } while ((x)->lock)
do { while (__raw_spin_is_locked(x)) cpu_relax(); } while (0)
/*
* Simple spin lock operations. There are two variants, one clears IRQ's