Re: Mapping frame buffer memory as uncached

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

On 20 December 2017 at 15:17, Alexei Fedorov <Alexei.Fedorov@arm.com> wrote:
> Hi Ard,
>
>
> The side effect of the following commit on 6 April:
>
>
> ArmPlatformPkg/FVP: map motherboard VRAM as uncached memory
>
> The VRAM of the PL111 on the FVP Base/Foundation models is described as
> device memory rather than uncached memory, which is not an accurate
> description of the nature of the region (i.e., a framebuffer), and may
> result in problems when using accelerated string routines to access the
> region, since this may legally involve unaligned accesses or DC ZVA
> instructions, which are not allowed on device mappings.
>
> So split of the 8 MB VRAM region into a separate region, and map it using
> memory attributes.
>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
> Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>
> is that now frame buffer memory region has Executable attribute set, which
> can be checked in DS-5 debugger Memory Map tab.
>
> Was this expected?
>

Not for one second. Thanks for the report, I will propose a fix.