From: "Jonathan (Zhixiong) Zhang" zjzhang@codeaurora.org
On a platform with APEI (ACPI Platform Error Interface) enabled, firmware updates a memory region with hardware error record using nocache attribute. When OS reads the region, since it maps the region with cache attribute even though EFI memory map defines this region as uncached, OS gets stale data and errorneously reports there is no new HW error.
When ghes driver maps the memory region, it uses the cache attribute according to EFI memory map, if EFI memory map feature is enabled.
Since both arch/x86 and arc/ia64 implemented architecture agnostic EFI memory map attribue lookup function, the code is moved from arch/x86 and arch/ia64 into EFI subsystem.
Jonathan (Zhixiong) Zhang (2): efi: arch, x86: arch, ia64: rearrange EFI memmap related functions acpi, apei: use EFI memmap to map GHES memory
arch/ia64/kernel/efi.c | 11 ----------- arch/x86/platform/efi/efi.c | 18 ------------------ drivers/acpi/apei/ghes.c | 13 +++++++++++++ drivers/firmware/efi/efi.c | 27 +++++++++++++++++++++++++++ include/linux/efi.h | 1 + 5 files changed, 41 insertions(+), 29 deletions(-)