Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [Suggestion] ARM64: kernel: compiling issue, need implement cmpxchg64 with assembler language. | Date | Sat, 20 Apr 2013 09:32:02 +0200 |
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On Saturday 20 April 2013 10:28:55 Chen Gang wrote: > > -------------------------------patch begin-------------------------------------- > > diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h > index 968b5cb..b572d2b 100644 > --- a/arch/arm64/include/asm/cmpxchg.h > +++ b/arch/arm64/include/asm/cmpxchg.h > @@ -170,4 +170,6 @@ static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old, > (unsigned long)(n), \ > sizeof(*(ptr)))) > > +#define cmpxchg64(ptr,o,n) cmpxchg((ptr),(o),(n)) > + > #endif /* __ASM_CMPXCHG_H */
Yes, this looks good. Please provide the same for cmpxchg64_local.
> -------------------------------patch end---------------------------------------- > > > > I think, we can also reference the implementation of s390: > it is in arch/s390/include/asm/cmpxchg.h. > since we are ARM64, excluding ARM(32,16...), we can only consider 64-bit. > if in the future, ARM64 and ARM are merged together: > we can use CONFIG_64BIT to switch the cmpxchg64 definition. > if define CONFIG_64BIT, use cmpxchg instead of cmpxchg64. > else, use the definition of ARM (arch/arm/include/asm/cmpxchg.h already defines cmpxchg64)
I would not worry aobut merging the two at the moment.
> -------------------------------reference begin---------------------------------- > > #ifdef CONFIG_64BIT > #define cmpxchg64(ptr, o, n) \ > ({ \ > cmpxchg((ptr), (o), (n)); \ > }) > #else /* CONFIG_64BIT */ > ... > -------------------------------reference end------------------------------------
This implementation in unnecessarily verbose, I think the one you have above is nicer.
Arnd
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