Re: [PATCH 5/5] ArmVirtPkg: enable non-executable DXE stack for all platforms

[Laszlo Ersek <lersek@redhat.com>]

On 03/01/17 17:31, Ard Biesheuvel wrote:
> Now that ARM has grown support for managing memory permissions in
> ArmMmuLib, we can enable the non-executable DXE stack for all virt
> platforms.
> 
> Note that this is not [entirely] redundant: the non-executable stack
> is configured before DxeCore is invoked. The image and memory protection
> features configured during DXE only take affect when the CPU arch
> protocol implementation is registered.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  ArmVirtPkg/ArmVirt.dsc.inc       | 5 +++++
>  ArmVirtPkg/ArmVirtQemu.dsc       | 2 --
>  ArmVirtPkg/ArmVirtQemuKernel.dsc | 2 --
>  3 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/ArmVirtPkg/ArmVirt.dsc.inc b/ArmVirtPkg/ArmVirt.dsc.inc
> index acfb71d3ff6c..e2d3dcce7945 100644
> --- a/ArmVirtPkg/ArmVirt.dsc.inc
> +++ b/ArmVirtPkg/ArmVirt.dsc.inc
> @@ -386,6 +386,11 @@ [PcdsFixedAtBuild.common]
>    #
>    gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy|0xC000000000007FD1
>  
> +  #
> +  # Enable the non-executable DXE stack. (This gets set up by DxeIpl)
> +  #
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|TRUE
> +
>  [PcdsFixedAtBuild.ARM]
>    gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize|40
>  
> diff --git a/ArmVirtPkg/ArmVirtQemu.dsc b/ArmVirtPkg/ArmVirtQemu.dsc
> index 615e1fca4877..477dfdcfc764 100644
> --- a/ArmVirtPkg/ArmVirtQemu.dsc
> +++ b/ArmVirtPkg/ArmVirtQemu.dsc
> @@ -152,8 +152,6 @@ [PcdsFixedAtBuild.common]
>    gEmbeddedTokenSpaceGuid.PcdPrePiCpuIoSize|16
>  
>  [PcdsFixedAtBuild.AARCH64]
> -  gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|TRUE
> -
>    # KVM limits it IPA space to 40 bits (1 TB), so there is no need to
>    # support anything bigger, even if the host hardware does
>    gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize|40
> diff --git a/ArmVirtPkg/ArmVirtQemuKernel.dsc b/ArmVirtPkg/ArmVirtQemuKernel.dsc
> index e4902690123c..fd39c2802a85 100644
> --- a/ArmVirtPkg/ArmVirtQemuKernel.dsc
> +++ b/ArmVirtPkg/ArmVirtQemuKernel.dsc
> @@ -163,8 +163,6 @@ [PcdsFixedAtBuild.AARCH64]
>    #
>    gEmbeddedTokenSpaceGuid.PcdPrePiCpuIoSize|16
>  
> -  gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|TRUE
> -
>    # KVM limits it IPA space to 40 bits (1 TB), so there is no need to
>    # support anything bigger, even if the host hardware does
>    gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize|40
> 

This doesn't just extend PcdSetNxForStack from AARCH64 from ARM, but
also from QEMU to Xen. Is that your intent? If so,

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo