On Fri, Nov 30, 2018 at 12:28:27PM +0100, Ard Biesheuvel wrote:
> The ARM ArmMmuLib code currently does not take into account that
> setting permissions on a region should take into account that a
> region may not be mapped yet to begin with.
>
> So when updating a section descriptor whose old value is zero,
> pass in the address explicitly.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindh...@linaro.org>
> ---
> ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> index ec51e072ab43..889b22867dc7 100644
> --- a/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> +++ b/ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c
> @@ -695,8 +695,12 @@ UpdateSectionEntries (
> } else {
> // still a section entry
>
> - // mask off appropriate fields
> - Descriptor = CurrentDescriptor & ~EntryMask;
> + if (CurrentDescriptor != 0) {
> + // mask off appropriate fields
> + Descriptor = CurrentDescriptor & ~EntryMask;
> + } else {
> + Descriptor = ((UINTN)FirstLevelIdx + i) <<
> TT_DESCRIPTOR_SECTION_BASE_SHIFT;
> + }
>
> // mask in new attributes and/or permissions
> Descriptor |= EntryValue;
> --
> 2.19.1
>
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