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author | Stuart Menefy <stuart.menefy@st.com> | 2007-11-30 16:12:36 +0900 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 13:18:58 +0900 |
commit | 1efe4ce3ca126da77e450d5a83f7201949d76f62 (patch) | |
tree | fbae9902aa4103a9e86d06f841d580f24682e7b3 /include/asm-sh/cmpxchg-irq.h | |
parent | 53ff09422e5e7a6d6198b767c8f494e43ec8e3ae (diff) | |
download | op-kernel-dev-1efe4ce3ca126da77e450d5a83f7201949d76f62.zip op-kernel-dev-1efe4ce3ca126da77e450d5a83f7201949d76f62.tar.gz |
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>
Diffstat (limited to 'include/asm-sh/cmpxchg-irq.h')
-rw-r--r-- | include/asm-sh/cmpxchg-irq.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/include/asm-sh/cmpxchg-irq.h b/include/asm-sh/cmpxchg-irq.h new file mode 100644 index 0000000..43049ec --- /dev/null +++ b/include/asm-sh/cmpxchg-irq.h @@ -0,0 +1,40 @@ +#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 */ |