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

On Fri, 2018-09-21 at 17:40 +0000, York Sun wrote:

On 09/20/2018 05:31 PM, Scott Wood wrote:

quoted

On Fri, 2018-09-21 at 00:48 +0200, David Lamparter wrote:

quoted

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