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@xxxxxxxxxx/ 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