unrecoverable exception on G5 with CONFIG_PPC_EARLY_DEBUG enabled

[Aneesh Kumar K.V]

Michael Ellerman <mpe at ellerman.id.au> writes:

> 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?
>

The 2f branch ends up doing unrecoverable exception. Or are you
suggesting something else ?

-aneesh