Define a PPI interface that may be used by the PEI core or other PEIMs
to manage permissions on memory ranges. This is primarily intended for
restricting permissions to what is actually needed for correct execution
by the code in question, and for limiting the use of memory mappings
that are both writable and executable at the same time.
Signed-off-by: Ard Biesheuvel <a...@kernel.org>
---
MdeModulePkg/Include/Ppi/MemoryAttribute.h | 78 ++++++++++++++++++++
MdeModulePkg/MdeModulePkg.dec | 3 +
2 files changed, 81 insertions(+)
diff --git a/MdeModulePkg/Include/Ppi/MemoryAttribute.h
b/MdeModulePkg/Include/Ppi/MemoryAttribute.h
new file mode 100644
index 0000000000000000..5ff31185ab4183f8
--- /dev/null
+++ b/MdeModulePkg/Include/Ppi/MemoryAttribute.h
@@ -0,0 +1,78 @@
+/** @file
+
+Copyright (c) 2023, Google LLC. All rights reserved.<BR>
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef EDKII_MEMORY_ATTRIBUTE_PPI_H_
+#define EDKII_MEMORY_ATTRIBUTE_PPI_H_
+
+#include <Uefi/UefiSpec.h>
+
+///
+/// Global ID for the EDKII_MEMORY_ATTRIBUTE_PPI.
+///
+#define EDKII_MEMORY_ATTRIBUTE_PPI_GUID \
+ { \
+ 0x1be840de, 0x2d92, 0x41ec, { 0xb6, 0xd3, 0x19, 0x64, 0x13, 0x50, 0x51,
0xfb } \
+ }
+
+///
+/// Forward declaration for the EDKII_MEMORY_ATTRIBUTE_PPI.
+///
+typedef struct _EDKII_MEMORY_ATTRIBUTE_PPI EDKII_MEMORY_ATTRIBUTE_PPI;
+
+/**
+ Set the requested memory permission attributes on a region of memory.
+
+ BaseAddress and Length must be aligned to EFI_PAGE_SIZE.
+
+ Both SetMask and ClearMask may contain any combination of EFI_MEMORY_RP,
+ EFI_MEMORY_RO and EFI_MEMORY_XP, with the following restrictions:
+ - each constant may appear in either SetMask or ClearMask, but not in both;
+ - SetMask or ClearMask may be 0x0, but not both.
+
+ @param[in] This The protocol instance pointer.
+ @param[in] BaseAddress The physical address that is the start address of
+ a memory region.
+ @param[in] Length The size in bytes of the memory region.
+ @param[in] SetMask Mask of memory attributes to set.
+ @param[in] ClearMask Mask of memory attributes to clear.
+
+ @retval EFI_SUCCESS The attributes were set for the memory region.
+ @retval EFI_INVALID_PARAMETER Length is zero.
+ Invalid combination of SetMask and ClearMask.
+ BaseAddress or Length is not suitably aligned.
+ @retval EFI_UNSUPPORTED The processor does not support one or more
+ bytes of the memory resource range specified
+ by BaseAddress and Length.
+ The bit mask of attributes is not supported for
+ the memory resource range specified by
+ BaseAddress and Length.
+ @retval EFI_OUT_OF_RESOURCES Requested attributes cannot be applied due to
+ lack of system resources.
+
+**/
+typedef
+EFI_STATUS
+(EFIAPI *EDKII_MEMORY_ATTRIBUTE_SET_PERMISSIONS)(
+ IN EDKII_MEMORY_ATTRIBUTE_PPI *This,
+ IN EFI_PHYSICAL_ADDRESS BaseAddress,
+ IN UINT64 Length,
+ IN UINT64 SetMask,
+ IN UINT64 ClearMask
+ );
+
+///
+/// This PPI contains a set of services to manage memory permission attributes.
+///
+struct _EDKII_MEMORY_ATTRIBUTE_PPI {
+ EDKII_MEMORY_ATTRIBUTE_SET_PERMISSIONS SetPermissions;
+};
+
+extern EFI_GUID gEdkiiMemoryAttributePpiGuid;
+
+#endif
+
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 95dd077e19b3a901..d65dae18aa81e569 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -528,6 +528,9 @@ [Ppis]
gEdkiiPeiCapsuleOnDiskPpiGuid = { 0x71a9ea61, 0x5a35, 0x4a5d, {
0xac, 0xef, 0x9c, 0xf8, 0x6d, 0x6d, 0x67, 0xe0 } }
gEdkiiPeiBootInCapsuleOnDiskModePpiGuid = { 0xb08a11e4, 0xe2b7, 0x4b75, {
0xb5, 0x15, 0xaf, 0x61, 0x6, 0x68, 0xbf, 0xd1 } }
+ ## Include/Ppi/MemoryAttribute.h
+ gEdkiiMemoryAttributePpiGuid = { 0x1be840de, 0x2d92, 0x41ec, {
0xb6, 0xd3, 0x19, 0x64, 0x13, 0x50, 0x51, 0xfb } }
+
[Protocols]
## Load File protocol provides capability to load and unload EFI image into
memory and execute it.
# Include/Protocol/LoadPe32Image.h
--
2.39.2
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