Re: 4.13-rc3: Unrecoverable exception 4100

Nicholas Piggin [off-list ref] writes:

On Fri, 04 Aug 2017 21:54:57 +0200
Andreas Schwab [off-list ref] wrote:

quoted

No, this is really a 4.13-rc1 regression.

Andreas.

SLB miss with MSR[RI]=0 on

lbz     r0,THREAD+THREAD_LOAD_FP(r7)

Caused by bc4f65e4cf9d6cc43e0e9ba0b8648cf9201cd55f

Ah of course. Not sure why I haven't seen it in any of my testing :/

Hmm, I'll see if something can be done, but that MSR_RI stuff in syscall
exit makes things fairly difficult (and will reduce performance improvement
of this patch anyway).

I'm trying to work to a point where we have a soft-RI bit for these kinds of
uses that would avoid all this complexity. Until then it may be best to
just revert this patch.

OK. Let me know in the next day or two what you want to do.

One option would be to load THREAD_LOAD_FP/THREAD_LOAD_VEC before we
turn off RI.

It would be ugly, but if we think we can clean it up in the medium term
with soft-RI then maybe that would be OK.

cheers