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SubjectRe: [PATCH] x86: Add an explicit barrier() to clflushopt()
On Mon, Oct 19, 2015 at 12:05:29PM +0100, Chris Wilson wrote:
> In order to add the clobbers, I had to adjust the macro slightly:
>
> +#define alternative_output(oldinstr, newinstr, feature, output) \
> + asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
> + : output : "i" (0) : "memory")
>
> and that also works. The concern I have here is that the asm does use
> "+m" as its output already, and the clflush() asm doesn't require the
> manual clobber.

Yeah, you could make the above

#define alternative_output(oldinstr, newinstr, feature, output, clobber...)

and use it to define clflushopt(). hpa might have a better idea, though...

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.


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