[Skiboot] [RFC/WIP/PATCH v2] Fast reboot for P8

[Benjamin Herrenschmidt]

On Wed, 2016-07-27 at 17:36 +1000, Michael Neuling wrote:
> er en
> Here's a slightly better version that handles multi-core/thread.
> 
> It uses the mambo callthru to run a tcl command to send the CPUs to
> 0x100.
> 
> mambo confuses skiboot a bit when the topology doesn't match real
> hardware (eg. when mambo configures a power8 with less than 8
> threads).  So we need to fix that up at some point.
> 
> mambo also seems to have some issues with not running any
> instructions
> on the threads when they are sent to 0x100 for many seconds. This
> means the reboot takes much longer than it needs to with many
> threads.
> We may need to reset the thread priorities to fix this.

This could be caused by what Nick found out: Mambo actually resets the
entire processor state when sending a soft-reset, including the
priorities (RPR). I think that is wrong though, we need to look
into it.

Cheers,
Ben.