[Skiboot] [PATCH v7 08/22] hdata: Add support for early OPAL crash

[Nicholas Piggin]

Vasant Hegde's on May 14, 2019 9:33 pm:
> On 05/09/2019 10:59 AM, Nicholas Piggin wrote:
>> Vasant Hegde's on April 13, 2019 7:15 pm:
>>> Lets hardcode few entries in MDST and MDDT table.. so that we can capture
>>> early OPAL crash. Note that we will have 1 to 1 mapping between MDST and
>>> MDDT table entry.
>> 
>> How useful is this? It could be useful if:
>> - crash is not reproducable, and
>> - customer site where we can't access the BMC, and
>> - system eventually boots so crash dump can be saved, and
>> - dump is sufficient to debug (i.e., debugging does not involve hardware
>>    registers etc).
> 
> Correct.
> 
>> 
>> I'm a bit skeptical. I reckon we'd get more milage out of changing assert
>> to trap so we get regs.
> 
> We do capture registers.. but yes, its useful only when system boots eventually.

I'd like to consider holding off the OPAL crash feature (presumably
the Linux dump is significantly more useful and has more moving parts
to solve). We should be able to improve boot crashes a lot without
this, and then reconsider if it's still wanted.

Thanks,
Nick