Re: [PATCH edk2-platforms v3 12/17] ARM/VExpressPkg: Allocate framebuffer using EfiRuntimeServicesData

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

On 21 March 2018 at 00:18, Girish Pathak <girish.pathak@arm.com> wrote:
> As per the UEFI specification(2.7) section 12.9, the GOP framebuffer
> memory can be accessed in the pre-boot and the post boot phase (by OS)
> Therefore the memory type EfiBootServicesData is incorrect for
> the framebuffer memory allocation. Change EfiBootServicesData with
> EfiRuntimeServicesData flag so that allocated memory can be access
> by the OS in the post boot phase.
>

EfiRuntimeServicesData is intended for allocations that the EFI
runtime services need to access themselves at runtime, and will hence
be virtually remapped by SetVirtualAddressMap().

This does not apply to the framebuffer. Even if it may be used at OS
runtime, the firmware itself will never access it, so
EfiRuntimeServicesData is not appropriate

Please use EfiReservedMemory instead.


> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Girish Pathak <girish.pathak@arm.com>
> Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
> ---
>  Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c       | 2 +-
>  Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
> index f7cae39c9cc9954ba4cad1bd597ebfc8baf10f11..c0a25a18d3fcfe91a76ee985ee58145b97900fa0 100644
> --- a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
> +++ b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
> @@ -176,7 +176,7 @@ LcdPlatformGetVram (
>    }
>    Status = gBS->AllocatePages (
>                    AllocationType,
> -                  EfiBootServicesData,
> +                  EfiRuntimeServicesData,
>                    EFI_SIZE_TO_PAGES (((UINTN)LCD_VRAM_SIZE)),
>                    VramBaseAddress
>                    );
> diff --git a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
> index 2f4814a2adbf01517ba14d75ce579ff35c362379..61ddf77e903e6c33a26b2aa8b76121e807195a9a 100644
> --- a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
> +++ b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
> @@ -232,7 +232,7 @@ LcdPlatformGetVram (
>      // Allocate the VRAM from the DRAM so that nobody else uses it.
>      Status = gBS->AllocatePages (
>                      AllocateAddress,
> -                    EfiBootServicesData,
> +                    EfiRuntimeServicesData,
>                      EFI_SIZE_TO_PAGES (((UINTN)LCD_VRAM_SIZE)),
>                      VramBaseAddress
>                      );
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>
>