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

[ppaidipe]

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.

> Balbir Singh.