On 16 November 2017 at 07:26, Jian J Wang <jian.j.w...@intel.com> wrote:
> Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as really
> set attributes and change memory paging attribute accordingly.
> But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by
> value from Capabilities in GCD memory map. This might cause
> boot problems. Clearing all paging related capabilities can
> workaround it. The code added in this patch is supposed to
> be removed once the usage of EFI_MEMORY_DESCRIPTOR.Attribute
> is clarified in UEFI spec and adopted by both EDK-II Core and
> all supported OSs.
>
> Cc: Jiewen Yao <jiewen....@intel.com>
> Cc: Star Zeng <star.z...@intel.com>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
> ---
> MdeModulePkg/Core/Dxe/Mem/Page.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c
> b/MdeModulePkg/Core/Dxe/Mem/Page.c
> index c9219cc068..783b576e35 100644
> --- a/MdeModulePkg/Core/Dxe/Mem/Page.c
> +++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
> @@ -1829,6 +1829,23 @@ CoreGetMemoryMap (
> //
> BufferSize = ((UINT8 *)MemoryMap - (UINT8 *)MemoryMapStart);
>
> + //
> + // WORKAROUND: Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as
> really
> + // set attributes and change memory paging attribute
> accordingly.
> + // But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by
> + // value from Capabilities in GCD memory map. This might cause
> + // boot problems. Clearing all paging related capabilities can
> + // workaround it. Following code is supposed to be removed once
> + // the usage of EFI_MEMORY_DESCRIPTOR.Attribute is clarified in
> + // UEFI spec and adopted by both EDK-II Core and all supported
> + // OSs.
> + //
> + while (MemoryMapStart < MemoryMap) {
> + MemoryMapStart->Attribute &= ~(UINT64)(EFI_MEMORY_RP | EFI_MEMORY_RO |
> + EFI_MEMORY_XP);
Why is EFI_MEMORY_WP missing here?
> + MemoryMapStart = NEXT_MEMORY_DESCRIPTOR(MemoryMapStart, Size);
> + }
> +
> Status = EFI_SUCCESS;
>
> Done:
> --
> 2.14.1.windows.1
>
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