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ArmPkg/ArmMmuLib: Implement EFI_MEMORY_RP using access flag

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Implement support for read-protected memory by wiring it up to the
access flag in the page table descriptor. The resulting mapping is
implicitly non-writable and non-executable as well, but this is good
enough for implementing this attribute, as we never rely on write or
execute permissions without read permissions.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
This commit is contained in:
Ard Biesheuvel
2023-02-07 16:09:56 +01:00
committed by mergify[bot]
parent 041c7a31c2
commit 6b821be140
4 changed files with 144 additions and 4 deletions
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34
ArmPkg/Include/Library/ArmMmuLib.h
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@@ -21,6 +21,40 @@ ArmConfigureMmu (
OUT UINTN *TranslationTableSize OPTIONAL
);
/**
Convert a region of memory to read-protected, by clearing the access flag.
@param BaseAddress The start of the region.
@param Length The size of the region.
@retval EFI_SUCCESS The attributes were set successfully.
@retval EFI_OUT_OF_RESOURCES The operation failed due to insufficient memory.
**/
EFI_STATUS
EFIAPI
ArmSetMemoryRegionNoAccess (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length
);
/**
Convert a region of memory to read-enabled, by setting the access flag.
@param BaseAddress The start of the region.
@param Length The size of the region.
@retval EFI_SUCCESS The attributes were set successfully.
@retval EFI_OUT_OF_RESOURCES The operation failed due to insufficient memory.
**/
EFI_STATUS
EFIAPI
ArmClearMemoryRegionNoAccess (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length
);
EFI_STATUS
EFIAPI
ArmSetMemoryRegionNoExec (