[PATCH v2 0/2] Add other fields to ARM trace event

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

This series was originally sent at:
https://lore.kernel.org/all/20240321-b4-arm-ras-error-vendor-info-v5-rc3-v5-0-850f9bfb97a8@os.amperecomputing.com/

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

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 there to actually parse such events on userspace,
for it to properly report/record the error nor to take appropriate measures
to prevent future problems, like poisoning problematic CPU cores and taking
them offline.

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.

---

- v2: fix a bad conflict resolution affecting non-arm compilation on patch 1.

- Changes over the original changeset:
  - First patch was simplified to avoid too many #ifdefs;
  - reordered local vars using reverse xmas tree;
  - removed uneeded typecasts;
  - some coding style fixes.


Daniel Ferguson (1):
  RAS: ACPI: APEI: add conditional compilation to ARM error report
    functions

Shengwei Luo (1):
  RAS: Report all ARM processor CPER information to userspace

 drivers/acpi/apei/ghes.c | 16 ++++++--------
 drivers/ras/ras.c        | 47 +++++++++++++++++++++++++++++++++++++--
 include/linux/ras.h      | 16 ++++++++++----
 include/ras/ras_event.h  | 48 +++++++++++++++++++++++++++++++++++-----
 4 files changed, 107 insertions(+), 20 deletions(-)

-- 
2.45.2