Re: [PATCH 11/15] purgatory: Core purgatory functionality

From: Vivek Goyal
Date: Mon Aug 11 2014 - 14:16:27 EST


On Mon, Aug 11, 2014 at 11:08:48AM -0700, H. Peter Anvin wrote:
> On 08/11/2014 11:02 AM, Vivek Goyal wrote:
> >
> > Hi hpa,
> >
> > I took it because kexec-tools uses it and in one of the committs Eric
> > gave following reasoning.
> >
> > On x86_64 use -mcmodel=large so that the code is built without
> > any 32bit assumptions. -mcmodel=medium and -mcmodel=small
> > result int code that has 32bit relocations against variables
> > that can live anywhere in the address space
> >
> > We do want to load purgatory anywhere in the address space.
> >
> > But if there are other ways to achieve the same thing, I will do that
> > change.
> >
> > So when you say "small PIC", I need to use -mcmodel=small and -fPIC?
> >
>
> Actually -fPIE is probably better than -fPIC.
>
> -mcmodel=large is incompatible with all other code out there, which
> means that even though it is supposed to work it will be poorly tested
> at best. So even despite the gcc version issue, using the small PIC
> model would be better.

Ok, I will give it a try.

Thanks
Vivek
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