Failed attempt to boot a (non-debug) head -r339076 on an old PowerMac G5 "Quad Core" (built via devel/powerpc64-gcc): Waking up CPU 1

[Andreas Tobler]

On 09.10.18 22:40, Andreas Tobler wrote:
> On 09.10.18 22:35, Mark Millard via freebsd-ppc wrote:
>> [Reverting head -r334498 in my head -r339076 context was enough to get
>> the G5 so-called "Quad Core" to boot just fine as a variant of
>> -r339076 .]
>>
>> On 2018-Oct-9, at 12:54 PM, Mark Millard <marklmi at yahoo.com> wrote:
>>
>>> On 2018-Oct-9, at 8:20 AM, Mark Millard <marklmi at yahoo.com> wrote:
>>>
>>>> [The stable/head mix seems to be a wrong idea: 11.2 gets past
>>>> the SMP: messages just fine on the so-called G5 "Quad Core".]
>>>>
>>>> On 2018-Oct-8, at 5:14 PM, Mark Millard <marklmi at yahoo.com> wrote:
>>>>
>>>>> On 2018-Oct-8, at 1:27 PM, Justin Hibbits <chmeeedalf at gmail.com> wrote:
>>>>>
>>>>>>> . . .
>>>>>>
>>>>>> It would be helpful to know the last known-good SVN revision, both for
>>>>>> Head and 11.x, as well as the oldest failing one.  Since my G5 bit the
>>>>>> dust, I can't check locally.
>>>>>
>>>> . . .
>>>
>>> There are examples of head's kernels that sometimes
>>> fail to get to the "SMP:" messages and sometimes work
>>> for getting there (and beyond). So:
>>>
>>> My reporting any example failure is a solid indicator
>>> of the "does not reach "SMP:" problem in that build.
>>> (All tries reached the waking message on at least cpu
>>> 1.)
>>>
>>> My reporting "worked" for a revision might be a
>>> misclassification. (This makes for a messier
>>> "binary-like search".)
>>>
>>> That said, the summary of the later detail is:
>>>
>>> head -r334494 kernel worked
>>> head -r334528 kernel failed
>>>
>>> (There is nothing between those for:
>>>
>>> https://artifact.ci.freebsd.org/snapshot/head/r*/powerpc/powerpc64/kernel.txz
>>>
>>> so getting a smaller range requires builds.
>>> I've not attempted that.)
>>>
>>> The only machine-dependent powerpc64 change between
>>> those 2 that I see is:
>>>
>>> Author: jhibbits
>>> Date: Fri Jun  1 21:37:20 2018
>>> New Revision: 334498
>>> URL:
>>> https://svnweb.freebsd.org/changeset/base/334498
>>>
>>>
>>> Log:
>>>    Increase powerpc64 KVA from ~7.25GB to 32GB
>>> . . .
>>>
>>> . . .
>>
>> In my -r339076 build context I reverted -r334498, did a
>> buildkernel, installed it, and rebooted into -r339076.
>>
>> The result booted just fine.
>>
>> It does appear that, for head, -r334498 makes the difference
>> for some reason.
> 
> Unfortunately I have to confirm your findings.

Mark, how much physical ram do you have? Can you adjust the 
VM_MAX_KERNEL_ADDRESS just below the amount of RAM you have and see if 
-CURRENT boots? Here it does, I have 14GB and I adjusted 
VM_MAX_KERNEL_ADDRESS to 12GB. It is just a trial to find out what is 
happening.

Thanks,
Andreas