Re: [kvm-ia64-devel] [PATCH 0/5] RFC: ia64/pv_ops: ia64 intrinsicsparavirtualization

[Isaku Y. <yam...@va...>]

On Wed, Mar 05, 2008 at 08:16:36AM +0800, Dong, Eddie wrote:
> Remove rest mailinglist since it is an implementation detail
> argument that may confuse more people.

kvm-ia64-devel-request seems to be accidentaly added. I dropped it.


> > In fact specifying "out0", "out1", ... as clobbered registers
> > in inline assembler code, gcc allocates them. and we can
> > clobber those registers.
> > 
> > However we can't clobber stacked registers out of specified ones
> > so that its conversion differs from C function calling one.
> > For example
> >         func()
> >                 // out0 and out1 are allocated.
> >                 paravirt_get_cpuid(index);
> >                         // asm volatile ("..."
> 
> We can add "mov out0=out0" here,
> I saw it works using a simple code for reference.
> 
> 
> Or we can use following code more effectively:
> 
>  .pushsection .parasections;\t .long ...; mov out0=out0;; .long
> ...;\t.popsection

Great. Clever idea.


> It seems there is a bug in AS binutil. 

That's bad. How about inserting dummy labels before .pushsection and
after .popsection? Or make the dummy instruction explicitly occupy
full one bundle like { mov out0=out0;;nop;nop; }.
Does it make difference?
-- 
yamahata