Re: uml and -regparm=3

H. Peter Anvin
2008-01-10T02:46:39Z

Andi Kleen wrote:
> On Wed, Jan 09, 2008 at 09:14:04PM -0500, Jeff Dike wrote:
>> On Wed, Jan 09, 2008 at 10:50:48PM +0100, Miklos Szeredi wrote:
>>>> FASTCALL is useless and should not make a difference. It enables
>>>> regparm on specific functions, but that should not make a difference
>>>> if it works or not.
>>> __down_write() in include/asm-x86/rwsem.h seems to assume, that the
>>> semaphore pointer is passed in %eax down to rwsem_down_write_failed(),
>>> so regparm does make a difference there.
>> And rwsem_down_write_failed seems to think it's getting the pointer in
>> %eax:
>
> That's a left over from when it was called by magic inline assembly.
> I suspect it would be better to switch it just over to stack args
> for consistent and then declare it asmlinkage
>

That seems to go in the wrong direction to me. It would make more sense
to gradually shift to asmlinkage actually being regparm=3. This, of
course, would require a different name (such as FASTCALL) until the
conversion is complete -- even if done as a single patch series.

-hpa