unrecoverable exception on G5 with CONFIG_PPC_EARLY_DEBUG enabled

[Michael Ellerman]

On Fri, 2016-06-17 at 08:33 +1000, Benjamin Herrenschmidt wrote:
> On Thu, 2016-06-16 at 22:49 +0300, Denis Kirjanov wrote:
> > -
> > +BEGIN_MMU_FTR_SECTION
> > +       b       2f
> > +END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX)
> >         andi.   r10,r12,MSR_RI  /* check for unrecoverable exception
> > */
> >         beq-    2f
> 
> Are we taking an SLB miss before we do the fixup maybe ?

Yeah that's the only explanation that makes any sense.

I think instead of patching down this low we should instead be redirecting SLB
misses to unknown_exception() when radix is enabled. Aneesh?

cheers