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

From: Stewart Smith <[email-masked]>
Date: Fri, 07 Jul 2017 10:28:13 +1000

Michael Ellerman <[email-masked]> writes:
> Stewart Smith <[email-masked]> writes:
>> Oliver O'Halloran <[email-masked]> 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.