Re: [PATCH v3 0/3] preadv & pwritev syscalls.

[David Miller]

From: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Date: Mon, 15 Dec 2008 16:03:11 +0000

> On Mon, Dec 15, 2008 at 12:36:14PM +0100, Gerd Hoffmann wrote:
> 
> > Next revision of the patch series, with the alignment issue fixed by
> > swapping the last two arguments as suggested by arch maintainers.
> > 
> > I've dropped the now-obsolete wrappers for mips.  Ralf, please
> > double-check.
> 
> It fixes the alignment issue but still won't work; on MIPS 32-bit userspace
> will pass the 64-bit argument in two registers but the 64-bit kernel code
> will assume it to be passed in a single registers.

Same on 32-bit sparc, and I assume 32-bit powerpc as well.

> I'm surprised this works for x86; does x86-64 code really expect 64-bit
> arguments as 2 32-bit arguments?

Args get pushed onto the stack, so perhaps it works by accident :)
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