Re: [PATCH V9 0/5] map GHES memory region according to EFI memory map

[Will Deacon <will.deacon@arm.com>]

Hi Jonathan,

On Thu, Jul 30, 2015 at 10:35:04PM +0100, Jonathan (Zhixiong) Zhang wrote:
> 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
> cacahed 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
> at runtime.
> 
> Since both arch/x86 and arch/ia64 implemented architecture agnostic EFI
> memory map attribue lookup function efi_memattributes(), the code is
> moved from arch/x86 into EFI subsystem and is declared as __weak; archs
> other than ia64 should not override the default implementation.
> 
> V9:
> 1. Rebased to arm64-upstream-14543 of arm64/master.
> 2. Match strict MM type in arch_apei_get_mem_attribute().

I guess this is all going via Matt's tree? I'm happy to take the new
memory type in arch/arm64/ if there's nothing currently queued, but I
suspect it makes more sense for it to stay together.

Will