[GIT PULL for v6.10-rc6] edac fixes for kernel 6.11

From: Mauro Carvalho Chehab
Date: Wed Jun 26 2024 - 05:34:02 EST


Hi Borislav,

Please pull from:
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac tags/edac/v6.10-1

For two patches that fix UEFI 2.6+ implementation of the ARM trace event,
as the original implementation was incomplete.

The patches on this series was sent at:
https://lore.kernel.org/all/20240321-b4-arm-ras-error-vendor-info-v5-rc3-v5-0-850f9bfb97a8@xxxxxxxxxxxxxxxxxxxxxx/

I did a couple of changes at the first patch addressing some coding style
issues. At the second patch, I replaced the original description to a proper
one identifying precisely why the patch is needed and what it does.

In summary:
changeset e9279e83ad1f ("trace, ras: add ARM processor error trace event")
was incomplete: it added a trace event that was reporting only some fields
of the CPER record generated for ARM processor from UEFI 2.6 spec.

Those are not enough to actually parse such events on userspace, nor to
take any actions like isolating problematic CPU cores.

The patch was validated with the help of an ARM EINJ code for QEMU:

https://github.com/mchehab/rasdaemon/wiki/error-injection

I tested the ghes and cper reports both with and without this change,
using different versions of rasdaemon, with and without support for
the extended trace event. Those are a summary of the test results:

- adding more fields to the trace events didn't break userspace API:
both versions of rasdaemon handled it;

- the rasdaemon patches to handle the new trace report was missing
a backward-compatibility logic. I fixed already. With that, rasdaemon
can handle both old and new trace events.

Btw, rasdaemon has gained support for the extended trace since its
version 0.5.8 (released in 2021). I didn't saw any issues there
complain about troubles on it, so either distros used on ARM servers
are using an old version of rasdaemon, or they're carrying on the trace
event changes as well.

Regards,
Mauro

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The following changes since commit 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0:


Thanks,
Mauro