kernel-ark/include/asm-sh/cmpxchg-irq.h
Stuart Menefy 1efe4ce3ca sh: GUSA atomic rollback support.
This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-01-28 13:18:58 +09:00

41 lines
796 B
C

#ifndef __ASM_SH_CMPXCHG_IRQ_H
#define __ASM_SH_CMPXCHG_IRQ_H
static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
{
unsigned long flags, retval;
local_irq_save(flags);
retval = *m;
*m = val;
local_irq_restore(flags);
return retval;
}
static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
{
unsigned long flags, retval;
local_irq_save(flags);
retval = *m;
*m = val & 0xff;
local_irq_restore(flags);
return retval;
}
static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
unsigned long new)
{
__u32 retval;
unsigned long flags;
local_irq_save(flags);
retval = *m;
if (retval == old)
*m = new;
local_irq_restore(flags); /* implies memory barrier */
return retval;
}
#endif /* __ASM_SH_CMPXCHG_IRQ_H */