[PATCH 04/13] arm64: Add new hcall HVC_CALL_FUNC

[Will Deacon]

On Wed, Sep 10, 2014 at 06:23:57PM +0100, Geoff Levand wrote:
> On Wed, 2014-09-10 at 18:07 +0100, Will Deacon wrote:
> > On Tue, Sep 09, 2014 at 11:49:04PM +0100, Geoff Levand wrote:
> > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> > > index 9ab5f70..a21cf51 100644
> > > --- a/arch/arm64/kernel/hyp-stub.S
> > > +++ b/arch/arm64/kernel/hyp-stub.S
> > > @@ -75,7 +75,17 @@ el1_sync:
> > >  1:	cmp	x10, #HVC_SET_VECTORS
> > >  	b.ne	1f
> > >  	msr	vbar_el2, x0
> > > +	b	2f
> > >  
> > > +1:	cmp	x10, #HVC_CALL_FUNC
> > > +	b.ne    1f
> > > +	mov	x29, lr
> > > +	mov	lr, x0
> > > +	mov	x0, x1
> > > +	mov	x1, x2
> > > +	mov	x2, x3
> > > +	blr	lr
> > > +	mov	lr, x29
> > 
> > Why are you clobbering x29?
> 
> I can change this to x28, unless you can recommend another?

How about something that's not callee saved?

Will