Re: [PATCH] powerpc: fix os-term usage on kernel panic

[Will Schmidt <will_schmidt@vnet.ibm.com>]

On Fri, 2007-11-30 at 16:56 +1100, Stephen Rothwell wrote:
> On Tue, 27 Nov 2007 18:15:59 -0600 Will Schmidt <will_schmidt@vnet.ibm.com> wrote:
> >
> > (resending with the proper "from" addr this time). 
> > 
> > 
> > I'm seeing some funky behavior on power5/power6 partitions with this
> > patch.    A "/sbin/reboot" is now behaving much more like a
> > "/sbin/halt".
> > 
> > Anybody else seeing this, or is it time for me to call an exorcist for
> > my boxes? 
> 
> On my Power5+ box, I get an error (code B200A101) logged every time I
> reboot and about half the time, the machine does not reboot but need to
> be power cycled. Removing the cited patch makes the error not by logged
> and reboots work fine.
> 
> Paul and I have been having a look at this and Paul has asked the
> architects for clarification of when os-term should be used.

The architects will have the correct answer of course.   

>From my reading of the papr, I've got the impression that there are two
possibilities.    

First, the os-term never returns, and it's up to the service processor
to do whatever it's going to do.  (call home, dump, something else).
Nothing we can do there. 

Second, os-term returns, and it's up to the OS to call into power-off or
system-reboot.
I think this is more likely.   I havn't followed the path back from
machine_restart to see exactly how we got there, but probably means a
bit more logic to decide whether to call into rtas_restart() or
pSeries_power_off() after the call to machine_shutdown.