[PATCH 10/20] ARM: hyp-stub: Use r1 for the soft-restart address

[Marc Zyngier]

On Sun, 19 Feb 2017 08:22:23 +0000
Ard Biesheuvel <ard.biesheuvel at linaro.org> wrote:

> On 17 February 2017 at 15:44, Marc Zyngier <marc.zyngier at arm.com> wrote:
> > It is not really obvious why the restart address should be in r3
> > when communicated to the hyp-stub. r1 should be perfectly adequate,
> > and consistent with the rest of the code.
> >
> > Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> > ---
> >  arch/arm/kernel/hyp-stub.S | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
> > index 8301db963d83..8fa521bd63d2 100644
> > --- a/arch/arm/kernel/hyp-stub.S
> > +++ b/arch/arm/kernel/hyp-stub.S
> > @@ -214,7 +214,7 @@ __hyp_stub_do_trap:
> >
> >  1:     teq     r0, #HVC_SOFT_RESTART
> >         bne     1f
> > -       bx      r3
> > +       bx      r1
> >
> >  1:     mov     r0, #-1
> >
> > @@ -258,10 +258,8 @@ ENTRY(__hyp_set_vectors)
> >  ENDPROC(__hyp_set_vectors)
> >
> >  ENTRY(__hyp_soft_restart)
> > -       mov     r3, r0
> >         mov     r0, #HVC_SOFT_RESTART
> >         __HVC(0)
> > -       mov     r0, r3
> >         ret     lr
> >  ENDPROC(__hyp_soft_restart)
> >  
> 
> /me confused. How does the address end up in r1?

I'm now very confused too. I just gave it another go on my A7 platform,
and it restarted just right, even if there is obviously junk in r1.
Guess I'm just bloody lucky.

Thanks for the heads up, I'll fix that for v2.

	M.
-- 
Without deviation from the norm, progress is not possible.