Re: [PATCH] ArmPlatformPkg: remove EFI_MEMORY_UC attribute from normal memory

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 8 September 2016 at 10:21, Leif Lindholm <leif.lindholm@linaro.org> wrote:
> On Thu, Sep 08, 2016 at 09:13:38AM +0100, Ard Biesheuvel wrote:
>> On ARM systems, mapping normal memory as device memory may have unintended
>> side effects, given that unaligned accesses or loads and stores with special
>> semantics (e.g., load/store exclusive) may fault or may not work as expected.
>> Similarly, DC ZVA instructions are only supported on normal memory, not
>> device memory.
>
> I think this is the right thing to do; Arguably, on the modern ARM
> architectures, UNCACHEABLE and WRITE_COMBINEABLE are mutually
> exclusive. I'll discuss with Charles whether we should codify this in
> the UEFI specification.
>
>> So remove the EFI_MEMORY_UC attribute that we set by default on system RAM.
>> If any region requires this attribute, it is up to the driver to set this
>> attribute, and to ensure that no offending operations are performed on it.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>

Pushed, thanks.

I will follow up with similar patches for OpenPlatformPkg