[PATCH ppc-next] powerpc/fsl-booke: don't load early TLB at once

[Scott Wood]

On Fri, 2018-09-21 at 17:40 +0000, York Sun wrote:
> On 09/20/2018 05:31 PM, Scott Wood wrote:
> > On Fri, 2018-09-21 at 00:48 +0200, David Lamparter wrote:
> > > This is a *partial* revert of "powerpc/85xx: Load all early TLB entries
> > > at once" (d9e1831a420267a7ced708bb259d65b0a3c0344d.)
> > > 
> > > My dusty old P4080DS just completely fails to boot (no output at all)
> > > without this revert.  I have no clue what's going on here, I just
> > > bisected it down and since it looks like an optimization to me I just
> > > reverted it - and voilá, the P4080 boots again.
> > 
> > It's not an optimization; it was required to get kdump working, at least
> > for certain choices of crash kernel location.  I just tried booting a 32-
> > bit kernel and did not see this problem -- but I don't have access to a
> > p4080ds anymore.  I tried with qemu e500mc, and also running a 32-bit
> > kernel on e6500 (needs a tiny change to get past SMP init, since 32-bit
> > isn't really supported on e6500, but you do get output even without that).
> > 
> > Do you have a JTAG that can be used to find out where it's hanging?  If
> > not, I can try to get early debug working (needs an early IOMMU mapping).
> > 
> > York, can you try booting the latest kernel on p4080ds?
> > 
> 
> Scott,
> 
> I haven't tried P4080DS for a long time. What defconfig do you use for
> this board? I tried latest master branch (commit a27fb6d983c7b5) with
> corenet_basic_defconfig, it didn't boot up. Kernel has an exception very
> early (pc ffffae80).
> 
> However, before I claimed the board, someone booted Linux 4.14.71 on
> this board. I need to track down where the image came from.

Use corenet32_smp_defconfig

corenet_basic_defconfig is just a fragment used by the makefiles in assembling
the final config.

-Scott