[Skiboot] [RFC PATCH] opal/xstop: Use nvram param to enable/disable sw checkstop.

[Mahesh Jagannath Salgaonkar]

On 12/15/2017 01:05 PM, ppaidipe wrote:
> On 2017-12-15 06:34, Balbir Singh wrote:
>> On Thu, 14 Dec 2017 22:45:48 +0530
>> ppaidipe <ppaidipe at linux.vnet.ibm.com> wrote:
>>
>>> Hi Mahesh
>>>
>>> On 2017-12-14 21:06, Mahesh J Salgaonkar wrote:
>>> > From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
>>> >
>>> > Add a mechanism to enable/disable sw checkstop by looking at nvram
>>> > option
>>> > opal-sw-xstop=<enable/disable>.
>>> >
>>> > For now this patch disables the sw checkstop trigger unless explicitly
>>> > enabled through nvram option 'opal-sw-xstop=enable'. This will
>>> allow an
>>> > opportunity to get host kernel in panic path or xmon for unrecoverable
>>> > HMIs or MCE, to be able to debug the issue effectively.
>>>
>>> It will be good to enable by default, and let's give control to user to
>>> disable
>>> the sw-xstop using nvram option. Otherwise all test infrastructures will
>>> break.
>>>
>>
>> It's the otherway around right? Lets look at what happens today
>>
>> 1. We get a software initiated checkstop on a WSP box
>> 2. The BMC decides to reboot the box after a timeout
>> 3. The BMC shows that a software initiated checkstop took place
>>
>> How is this useful?
> 
> you are right it is of less useful in case of BMC systems, but still we
> can stop
> the auto reboot after checkstop and use existing pdbg tools to collect
> require debug
> data(Not sure how much useful it can capture).
> 
> 
>>
>> On the FSP side, we should still log our diagnostic information
>> before the OS reboots.
>>
> 
> Correct.
> 
>> Am I missing something?
>>
> 
> And it disables for all P8 platforms as well. So atleast we can enable
> it there.

Hmm.. We can add p9 check and keep the p8 behaviour as is. Would that help ?

Thanks,
-Mahesh.

> 
>> Balbir Singh.