[PATCH v5 0/4] fix CPER issues related to UEFI 2.9A Errata

Mauro Carvalho Chehab
2024-06-24T09:19:50Z

The UEFI 2.9A errata makes clear how ARM processor type encoding should
be done: it is meant to be equal to Generic processor, using a bitmask.

The current code assumes, for both generic and ARM processor types
that this is an integer, which is an incorrect assumption.

Fix it. While here, also fix a compilation issue when using W=1.

After the change, Kernel will properly decode receiving two errors at the same
message, as defined at UEFI spec:

[ 75.282430] Memory failure: 0x5cdfd: recovery action for free buddy page: Recovered
[ 94.973081] {2}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1
[ 94.973770] {2}[Hardware Error]: event severity: recoverable
[ 94.974334] {2}[Hardware Error]: Error 0, type: recoverable
[ 94.974962] {2}[Hardware Error]: section_type: ARM processor error
[ 94.975586] {2}[Hardware Error]: MIDR: 0x000000000000cd24
[ 94.976202] {2}[Hardware Error]: Multiprocessor Affinity Register (MPIDR): 0x000000000000ab12
[ 94.977011] {2}[Hardware Error]: error affinity level: 2
[ 94.977593] {2}[Hardware Error]: running state: 0x1
[ 94.978135] {2}[Hardware Error]: Power State Coordination Interface state: 4660
[ 94.978884] {2}[Hardware Error]: Error info structure 0:
[ 94.979463] {2}[Hardware Error]: num errors: 3
[ 94.979971] {2}[Hardware Error]: first error captured
[ 94.980523] {2}[Hardware Error]: propagated error captured
[ 94.981110] {2}[Hardware Error]: overflow occurred, error info is incomplete
[ 94.981893] {2}[Hardware Error]: error_type: 0x0006: cache error|TLB error
[ 94.982606] {2}[Hardware Error]: error_info: 0x000000000091000f
[ 94.983249] {2}[Hardware Error]: transaction type: Data Access
[ 94.983891] {2}[Hardware Error]: cache error, operation type: Data write
[ 94.984559] {2}[Hardware Error]: TLB error, operation type: Data write
[ 94.985215] {2}[Hardware Error]: cache level: 2
[ 94.985749] {2}[Hardware Error]: TLB level: 2
[ 94.986277] {2}[Hardware Error]: processor context not corrupted

And the error code is properly decoded according with table N.17 from UEFI 2.10
spec:

[ 94.981893] {2}[Hardware Error]: error_type: 0x0006: cache error|TLB error

The error injection logic was checked via QEMU using this patch:
https://lore.kernel.org/all/20240621165115.336-1-shiju.jose@huawei.com/

v5:
- Do some cleanups and minor fixes as suggested by Jonathan and Tony:
- check errors at strscpy();
- simplify cper_bits_to_str() function;
- use FIELD_GET() and for_each_set_bit();
- use ARRAY_SIZE() on infofx to let it clear that it should be size of newpfx + 1;
- fix kernel-doc warning with W=1;
- use kernel-doc for two exported functions at cper.c.

v4:
- The print function had some bugs on it, which was discovered with
the help of an error injection tool I'm now using.

v3:
- It adds a helper function to produce a buffer describing the
error bits at cper's printk and ghes pr_warn_bitrated. It also
fixes a W=1 error while building cper.

v2:
- It fixes the way printks are handled on both cper_arm and ghes
drivers.

v1:
- (tagged as RFC) was mostly to give a heads up that the current
implementation is not following the spec. It also touches
only cper code.

Mauro Carvalho Chehab (4):
efi/cper: Adjust infopfx size to accept an extra space
efi/cper: Add a new helper function to print bitmasks
efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs
docs: efi: add CPER functions to driver-api

.../driver-api/firmware/efi/index.rst | 11 ++--
drivers/acpi/apei/ghes.c | 15 +++---
drivers/firmware/efi/cper-arm.c | 52 +++++++++----------
drivers/firmware/efi/cper.c | 41 ++++++++++++++-
include/linux/cper.h | 12 +++--
5 files changed, 89 insertions(+), 42 deletions(-)

--
2.45.2