Re: [PATCH] ArmPkg-Drivers/CpuDxe: Fix Mmu Initialization Problem.

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

On 26 September 2016 at 15:49, Kurt Kennett <Kurt.Kennett@microsoft.com> wrote:
> During Mmu initialization in the CpuDxe, for a page table any bits set
> in the 'NextSectionAttributes' are garbage and were set from bits that
> are actually part of the pagetable address.  We clear it out to zero
> so that the SyncCacheConfigPage will use the page attributes instead
> of trying to convert the (bogus) section attributes into page
> attributes.
>
> Contributed-under: TianoCore Contribution Agreement 1.0
>
> Signed-off-by: Kurt Kennett <mailto:kurt.kennett@microsoft.com>
> ---
> ArmPkg/Drivers/CpuDxe/Arm/Mmu.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
> b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c index 63da8ba..64ef1bb 100644
> --- a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
> +++ b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
> @@ -297,6 +297,11 @@ SyncCacheConfig (
>        }
>        NextRegionLength += TT_DESCRIPTOR_SECTION_SIZE;
>      } else if (TT_DESCRIPTOR_SECTION_TYPE_IS_PAGE_TABLE(FirstLevelTable[i])) {
> +      // In this case any bits set in the 'NextSectionAttributes' are garbage and were set from
> +      // bits that are actually part of the pagetable address.  We clear it out to zero so that
> +      // the SyncCacheConfigPage will use the page attributes instead of trying to convert the
> +      // section attributes into page attributes
> +      NextSectionAttributes = 0;
>        Status = SyncCacheConfigPage (
>            i,FirstLevelTable[i],
>            NumberOfDescriptors, MemorySpaceMap,
> --
> 2.9.0.windows
>

Reviewed-by: Ard Biesheuve <ard.biesheuvel@linaro.org>

Pushed as f6be48e9907d

Thanks Kurt!