[Skiboot] Skiboot upgrade needed for VAS/NX
sukadev at linux.vnet.ibm.com
Wed Sep 6 11:22:57 AEST 2017
Oliver [oohall at gmail.com] wrote:
> On Wed, Sep 6, 2017 at 4:10 AM, Sukadev Bhattiprolu
> <sukadev at linux.vnet.ibm.com> wrote:
> > Please note that if you are testing recent powerpc/next code with CONFIG_VAS
> > enabled on a DD2 system, please upgrade to latest skiboot (5.8).
> > Otherwise you will run into a machine check like this one reported by
> > Nick Piggin.
> What's the underlying issue here? We're supposed to avoid this sort of
> issue though compat strings, etc. What bug is fixed in 5.8 that solves
DD2 hardware required setting three new enable bits, without which a write
to the VAS registers results in a machine check. Following commit fixed
that. DD1 did not need these to be set.
Author: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
Date: Thu Aug 17 17:50:24 2017 -0700
vas: Set mmio enable bits in DD2
POWER9 DD2 added some new "enable" bits that must be set for VAS to
work. These bits were unused in DD1.
There was also a bug in the setting of FIRs which results in the checkstop.
for potentially recoverable errors. That was fixed by:
Author: Michael Neuling <mikey at neuling.org>
Date: Mon Aug 21 17:16:06 2017 +1000
vas: Set FIRs according to workbook
Both fixes are in 5.8 skiboot.
All these registers are set using SCOM so they are initialized in skiboot
rather than by the kernel. Are there ways we can fix the kernel without
requiring a skiboot change?
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