Re: [PATCH 4/8] unify paravirt parts of system.h

[Pavel Machek <pavel@ucw.cz>]

On Mon 2007-12-17 01:27:29, Rafael J. Wysocki wrote:
> On Saturday, 15 of December 2007, Ingo Molnar wrote:
> > 
> > * Pavel Machek <pavel@ucw.cz> wrote:
> > 
> > > > Linux never uses that register. The only user is suspend 
> > > > save/restore, but that' bogus because it wasn't ever initialized by 
> > > > Linux in the first place. It could be probably all safely removed.
> > > 
> > > It probably is safe to remove... but we currently support '2.8.95 
> > > kernel loads/resumes 2.6.24 image'... which would break if 2.8 uses 
> > > cr8.
> > > 
> > > So please keep it if it is not a big problem.
> > 
> > hm, so __save_processor_state() is in essence an ABI? Could you please 
> > also send a patch that documents this prominently, in the structure 
> > itself?
> 
> Hmm, I'm not sure if it really is an ABI part.  It doesn't communicate anything
> outside of the kernel in which it is defined.

Well, it is not "application binary interface", but it is
"kernel-to-kernel binary interface"...

> The problem is, though, that if kernel A is used for resuming kernel B, and
> kernel B doesn't save/restore everything it will need after the resume, then
> things will break if kernel A modifies that.  So, yes, we'll need to document
> that explicitly.

Agreed.
									Pavel
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