[PATCH RFC] powerpc/powernv: sysfs entry to force full IPL reboot

[Michael Ellerman]

Andrew Donnellan <andrew.donnellan at au1.ibm.com> writes:

> On 23/11/16 12:37, Andrew Donnellan wrote:
>>> There's existing logic in kernel/reboot.c to handle a reboot= command
>>> line parameter, which can set the reboot_mode, so my preference would be
>>> that we use that.
>>>
>>> Currently we completely ignore the reboot_mode, so there's no backward
>>> compatibility issue.
>>>
>>> It looks like the default is REBOOT_COLD, whatever that means. So I
>>> think we could define that on powernv REBOOT_HARD means "do a full IPL".
>>
>> Sounds good.
>
> Thinking about this more - you can't change that at runtime. :(

Yeah. Is that a problem? From my POV this is basically a "my firmware is
broken" workaround, so you're going to want to set it permanently until
you update your firmware.

>>> Or we could use "force", which already exists, though I can't quite see
>>> what that actually means on x86.
>>
>> Hmm.
>
> It looks like that on x86, if reboot_force = 1, we don't call 
> machine_shutdown() and go straight to __machine_emergency_restart()?

I think so. But I don't know what that actually means from a user's
point of view.

cheers