Re: unrecoverable exception on G5 with CONFIG_PPC_EARLY_DEBUG enabled

Michael Ellerman [off-list ref] writes:

On Fri, 2016-06-17 at 08:33 +1000, Benjamin Herrenschmidt wrote:

quoted

On Thu, 2016-06-16 at 22:49 +0300, Denis Kirjanov wrote:

quoted

-
+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