Re: [uml-devel] User Mode Linux still doesn't build in2.6.23-final.

From: Adrian Bunk
Date: Tue Oct 23 2007 - 09:24:43 EST


On Tue, Oct 23, 2007 at 10:45:46AM +0200, Ingo Molnar wrote:
>
> * Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>
> > >> Should we re-add them for the function pointers in
> > >> asm-x86/paravirt.h?
> > >
> > > yes, yes, yes. :-) It was a nightmare to sort it out in -rt (and
> > > still is).
> >
> > Do you have a patch to do this already?
>
> yes, attached. Ack?
>
> Ingo
>
> ---------------------------->
> Subject: [patch] paravirt: mark assembly dependencies as fastcall
> From: Ingo Molnar <mingo@xxxxxxx>
>
> the 'fastcall removal' changes to paravirt.c were over-eager: they
> removed fastcall annotations from functions that are (or might be)
> implemented in assembly. So if someone changes the compiler model,
> such as -pg which disables regparm, the kernel breaks in nasty ways.
>
> so this patch adds back fastcall annotations. This serves as
> documentation for assembly calling-convention dependencies as
> well.
>...

I see a point in annotating all C code called from assembler code with
either fastcall or asmlinkage, but how will these annotations be
maintained?

Without anything giving at least a warning these annotations will simply
bitrot.

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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