lkml.org 
[lkml]   [2014]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] x86: Mark __vdso entries as asmlinkage
On 02/27/2014 12:11 PM, Andy Lutomirski wrote:
>
> Hmm. This sort of goes against existing x86_32 practice where,
> AFAICT, things that need a particular calling convention specify
> asmlinkage and everything else uses regparm(3) if config/kbuild thinks
> it's appropriate.
>

That is not really true for things that aren't part of the kernel image
proper (e.g. the real mode code and so on.) This is a very special case.

> But I'm happy to resubmit the patch if you prefer the CFLAGS approach
> for the 32-bit vdso. I don't think anything will break, since I don't
> think that the 32-bit vdso has any other exported C code.

I think it is the better way to go.

>> It isn't any faster if the C library has to provide a wrapper just to
>> marshal parameters.
>
> Probably true, given that the glibc wrapper could, in principle, use
> an optimized tail call. Also, I see no reason why vdso functions,
> alone of all userspace code, should be special.

Yes, let's stick to the standard ABI. The syscall entry point was very
special.

-hpa




\
 
 \ /
  Last update: 2014-02-28 01:01    [W:0.101 / U:35.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site