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ArmPkg/ArmMmuLib: Disable and re-enable MMU only when needed

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When updating a page table descriptor in a way that requires break
before make, we temporarily disable the MMU to ensure that we don't
unmap the memory region that the code itself is executing from.

However, this is a condition we can check in a straight-forward manner,
and if the regions are disjoint, we don't have to bother with the MMU
controls, and we can just perform an ordinary break before make.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
This commit is contained in:
Ard Biesheuvel
2022-09-24 18:26:19 +02:00
committed by mergify[bot]
parent ab644cfac5
commit 0487cac09f
3 changed files with 123 additions and 29 deletions
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7
ArmPkg/Include/Library/ArmMmuLib.h
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@@ -52,9 +52,10 @@ ArmClearMemoryRegionReadOnly (
VOID
EFIAPI
ArmReplaceLiveTranslationEntry (
IN UINT64 *Entry,
IN UINT64 Value,
IN UINT64 RegionStart
IN UINT64 *Entry,
IN UINT64 Value,
IN UINT64 RegionStart,
IN BOOLEAN DisableMmu
);
EFI_STATUS