[RFC PATCH] ARM: cmpxchg: define __HAVE_ARCH_CMPXCHG for armv6 and later

[Will Deacon]

Hello,

On Wed, May 30, 2012 at 08:51:26AM +0100, Yong Zhang wrote:
> diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h
> index 7eb18c1..a91b44e 100644
> --- a/arch/arm/include/asm/cmpxchg.h
> +++ b/arch/arm/include/asm/cmpxchg.h
> @@ -127,6 +127,8 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
>  
>  #else	/* min ARCH >= ARMv6 */
>  
> +#define __HAVE_ARCH_CMPXCHG 1
> +
>  extern void __bad_cmpxchg(volatile void *ptr, int size);

As long as this only requires 4-byte cmpxchg support then I think this is
fine. It looks like that's currently the case, so:

Acked-by: Will Deacon <will.deacon at arm.com>

Will