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SubjectRe: [PATCH 1/2] x86: Mark __vdso entries as asmlinkage
On 02/26/2014 09:19 PM, Andy Lutomirski wrote:
>>
>> The normal ABI almost certainly makes more sense; as such -mregparm=3 is
>> probably not what we want, and I suspect it makes more sense to just
>> drop that from the CFLAGS line?
>
> Hmm. What happens on a native 32-bit build? IIRC the whole kernel is
> build with regparm(3).
>

Well, the vdso is still built separately, so we can use different CFLAGS
if we want to.

> If we want to save a cycle or two, then regparm(3) is probably faster.
> But I think that these functions should either be asmlinkage or (on
> 32 bit builds) explicitly regparm(3) to avoid confusion.

I suggest using the standard ABI, but I suggest doing it via CFLAGS.

It isn't any faster if the C library has to provide a wrapper just to
marshal parameters.

-hpa




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