[Skiboot] [PATCH] IPMI: Trigger attention in abort path.

[Mahesh J Salgaonkar]

On 2019-10-24 15:48:38 Thu, Oliver O'Halloran wrote:
> On Thu, Oct 24, 2019 at 3:21 AM Mahesh Salgaonkar
> <mahesh at linux.vnet.ibm.com> wrote:
> >
> > OpenBMC is capable of catching attn instruction as TI and facilitate in
> > rebooting (IPL-ing) host while keeping a reboot counter. This functionality
> > was not present with other BMCs e.g. SMC and AMI. And hence OPAL never used
> > to trigger an attn during abort/assert path for BMC based system. Instead
> > it always triggered normal reboot during abort. This means that BMC never
> > gets notified about OPAL termination/reboot. This sometimes leads into
> > never ending IPL-ing loop if OPAL keeps aborting very early in boot path.
> > This can be avoided on OpenBMC system that supports handling of TI (attn
> > instruction).
> 
> What versions of openbmc support the feature? I'm going to assume that
> it's not all of them.

So it looks like this feature been always present in openbmc.

> > +       if (platform.bmc->sw->attn_supported) {
> > +               /* Put everybody in stop/quiesce except myself. */
> > +               sreset_all_prepare();
> > +               trigger_attn();
> > +               for (;;) ;
> 
> It might be a good idea to quiesce the secondaries regardless. Is
> there any drawbacks to that?

Yeah, you are right. I don't see any drawbacks. I any case we are
rebooting after that. Will move sreset_all_prepare() above if statement
in v2.

Thanks,
-Mahesh.