Re: [Xen-devel] [PATCH v5 04/10] x86: Add support for STAC/CLAC instructions

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.05.14 at 12:07, <feng.wu@xxxxxxxxx> wrote:
> +static inline void clac(void)
> +{
> +    if ( boot_cpu_has(X86_FEATURE_SMAP) )
> +        asm volatile (__stringify(__ASM_CLAC));
> +}
> +
> +static inline void stac(void)
> +{
> +    if ( boot_cpu_has(X86_FEATURE_SMAP) )
> +        asm volatile (__stringify(__ASM_STAC));
> +}
> +#endif

Hmm, did you really mean to lose the memory clobbers here? In the
previous round's review I specifically said that this conversion to C
is likely only safe due to their presence.

Jan


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