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SubjectRe: [PATCH 1/3] mce: Add a msg string to the MCE tracepoint
Em 29-02-2012 14:20, Luck, Tony escreveu:
>> IMHO, before removing those fields, it would be better to first implement
>> what is there at the mcelog userspace parser for the Intel machines into
>> kernelspace (or to look into its source code), and check what registers
>> aren't used by either AMD 64 MCE decoder or by the Intel MCE decoder.
>> Tony,
>> Is there anyone at Intel working on porting it to kernelspace?
> The mcelog code just looks at model specific fields in MCi_STATUS
> and MCi_MISC. We could move it to the kernel - but I don't see
> much value in doing so.

I see a few reasons:

- it would be consistent with what's being done at AMD. So, all x86
arch will report errors at the same way;

- userspace won't need to run an extra daemon/tool to decode the

- fatal errors won't be lost (well, in fact, you have there already
a parser for fatal errors. Not sure if all possible fatal errors
are covered here, nor what else is needed, as you have already
there part of mcelog decoder);

- a single place to maintain, when new cpu families are added;

- it makes easier to centralize the hardware error information,
as there's no need to enrich the error on userspace.

> In this case all the information we need
> is carried in status/misc - so as long as we keep all of those
> bits (and the cpu family/model) we can safely decode/analyze later.

Hmm... the mcelog tool opens the /proc/cpuinfo:

$ grep cpuinfo *
mcelog.c: f = fopen("/proc/cpuinfo","r");
mcelog.c: Eprintf("warning: Cannot parse /proc/cpuinfo\n");
mcelog.c: Eprintf("warning: Cannot open /proc/cpuinfo\n");
tsc.c: asprintf(&fn, "/sys/devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", cpu);
tsc.c: /* /sys exists, but no cpufreq -- use value from cpuinfo */

That probably means that the needed cpu family/model info is not (or may not) be
stored at the MCE structure.

> -Tony

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