[Skiboot] [RFC PATCH] powerpc/powernv: report error messages from opal

Stewart Smith stewart at linux.vnet.ibm.com
Fri Jul 7 10:28:13 AEST 2017

Michael Ellerman <mpe at ellerman.id.au> writes:
> Stewart Smith <stewart at linux.vnet.ibm.com> writes:
>> Oliver O'Halloran <oohall at gmail.com> writes:
>>> diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
>>> index 0e2e57bcab50..cb9c0e6afb33 100644
>>> --- a/arch/powerpc/include/asm/opal-api.h
>>> +++ b/arch/powerpc/include/asm/opal-api.h
>>> @@ -167,7 +167,8 @@
>>>  #define OPAL_INT_EOI				124
>>>  #define OPAL_INT_SET_MFRR			125
>>>  #define OPAL_PCI_TCE_KILL			126
>>> -#define OPAL_LAST				126
>>> +#define OPAL_SCRAPE_LOG				128
>> (another thought, along with the skiboot thoughts), I don't like the
>> SCRAPE_LOG name so much, as it's more of a "hey linux, here's some log
>> messages from firmware, possibly before you were
>> involved"... OPAL_FETCH_LOG ?
> I'm not a huge fan of an interrupt followed by an opal call just to
> fetch a single line of log.
> Can't we do something more like the existing msglog code, where we have
> a ring buffer and then the interrupt just becomes "hey Linux you should
> look at your ring buffer".

Yeah... that would probably be a bit better...

Although that would mean we can only ever tell the running kernel what's
in the ring buffer. We couldn't work out a way to (after kexec) resend
important bits of info such as "we garded things out, your OCC didn't
start and we trained everything at really slow speeds"

Stewart Smith
OPAL Architect, IBM.

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