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

[York Sun]

On 09/21/2018 10:47 AM, Scott Wood wrote:
> 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.
> 

Thanks for the instruction. Linux comes up OK with corenet32_smp_defconfig.

root at p4080ds:~# uname -a
Linux p4080ds 4.19.0-rc4-00206-ga27fb6d #1 SMP Fri Sep 21 10:56:36 PDT
2018 ppc GNU/Linux

York