Create the MMU access lib to abstract memory protection settings

There are a number of Arm-specific accesses that are abstracted
behind this. It may need to be refactored to work better across
architectures.

MdePkg/Include/Library/MmuLib.h

@@ -0,0 +1,73 @@
+/** @file
+This lib abstracts some of the MMU accesses currently hardcoded against
+an Arm lib. It's likely that this will need to be refactored at some point.
+
+Copyright (c) Microsoft Corporation.
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef _MMU_LIB_H_
+#define _MMU_LIB_H_
+
+#include <Uefi.h>
+
+/**
+  Bitwise sets the memory attributes on a range of memory based on an attributes mask.
+
+  @param  BaseAddress           The start of the range for which to set attributes.
+  @param  Length                The length of the range.
+  @param  Attributes            A bitmask of the attributes to set. See "Physical memory
+                                protection attributes" in UefiSpec.h
+
+  @return EFI_SUCCESS
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuSetAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINT64                Length,
+  IN  UINT64                Attributes
+  );
+
+/**
+  Bitwise clears the memory attributes on a range of memory based on an attributes mask.
+
+  @param  BaseAddress           The start of the range for which to clear attributes.
+  @param  Length                The length of the range.
+  @param  Attributes            A bitmask of the attributes to clear. See "Physical memory
+                                protection attributes" in UefiSpec.h
+
+  @return EFI_SUCCESS
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuClearAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINT64                Length,
+  IN  UINT64                Attributes
+  );
+
+/**
+  Returns the memory attributes on a range of memory.
+
+  @param  BaseAddress           The start of the range for which to set attributes.
+  @param  Attributes            A return pointer for the attributes.
+
+  @return EFI_SUCCESS
+  @return EFI_INVALID_PARAMETER   A return pointer is NULL.
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuGetAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  OUT UINT64                *Attributes
+  );
+
+#endif // _MMU_LIB_H_

MdePkg/Library/BaseMmuLibNull/BaseMmuLibNull.c

@@ -0,0 +1,84 @@
+/** @file
+This lib abstracts some of the MMU accesses currently hardcoded against
+an Arm lib. It's likely that this will need to be refactored at some point.
+
+Copyright (c) Microsoft Corporation.
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <Library/DebugLib.h>
+
+/**
+  Bitwise sets the memory attributes on a range of memory based on an attributes mask.
+
+  @param  BaseAddress           The start of the range for which to set attributes.
+  @param  Length                The length of the range.
+  @param  Attributes            A bitmask of the attributes to set. See "Physical memory
+                                protection attributes" in UefiSpec.h
+
+  @return EFI_SUCCESS
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuSetAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINT64                Length,
+  IN  UINT64                Attributes
+  )
+{
+  DEBUG ((DEBUG_ERROR, "%a() NULL implementation used!\n", __FUNCTION__));
+  ASSERT (FALSE);
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Bitwise clears the memory attributes on a range of memory based on an attributes mask.
+
+  @param  BaseAddress           The start of the range for which to clear attributes.
+  @param  Length                The length of the range.
+  @param  Attributes            A bitmask of the attributes to clear. See "Physical memory
+                                protection attributes" in UefiSpec.h
+
+  @return EFI_SUCCESS
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuClearAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN  UINT64                Length,
+  IN  UINT64                Attributes
+  )
+{
+  DEBUG ((DEBUG_ERROR, "%a() NULL implementation used!\n", __FUNCTION__));
+  ASSERT (FALSE);
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Returns the memory attributes on a range of memory.
+
+  @param  BaseAddress           The start of the range for which to set attributes.
+  @param  Attributes            A return pointer for the attributes.
+
+  @return EFI_SUCCESS
+  @return EFI_INVALID_PARAMETER   A return pointer is NULL.
+  @return Others
+
+**/
+EFI_STATUS
+EFIAPI
+MmuGetAttributes (
+  IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
+  OUT UINT64                *Attributes
+  )
+{
+  DEBUG ((DEBUG_ERROR, "%a() NULL implementation used!\n", __FUNCTION__));
+  ASSERT (FALSE);
+  return EFI_UNSUPPORTED;
+}

MdePkg/Library/BaseMmuLibNull/BaseMmuLibNull.inf

@@ -0,0 +1,29 @@
+## @file
+# This lib abstracts some of the MMU accesses currently hardcoded against
+# an Arm lib. It's likely that this will need to be refactored at some point.
+#
+##
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+
+[Defines]
+  INF_VERSION         = 0x00010017
+  BASE_NAME           = BaseMmuLibNull
+  FILE_GUID           = 97196A48-00C0-4487-802A-CC5540583EEB
+  VERSION_STRING      = 1.0
+  MODULE_TYPE         = BASE
+  LIBRARY_CLASS       = MmuLib
+
+
+[Sources]
+  BaseMmuLibNull.c
+
+
+[LibraryClasses]
+  DebugLib
+
+
+[Packages]
+  MdePkg/MdePkg.dec

MdePkg/MdePkg.dec

@@ -274,14 +274,19 @@
   #
   #
   RegisterFilterLib|Include/Library/RegisterFilterLib.h
-
   ##  @libraryclass  This library provides interfances to probe ConfidentialComputing guest type.
   #
   #
   CcProbeLib|Include/Library/CcProbeLib.h
 
   ## @libraryclass  Provides function for SMM CPU Rendezvous Library.
   SmmCpuRendezvousLib|Include/Library/SmmCpuRendezvousLib.h
+# MU_CHANGE [BEGIN]
+  ##  @libraryclass This lib abstracts some of the MMU accesses currently hardcoded against
+  #                 an Arm lib. It's likely that this will need to be refactored at some point.
+  #
+  MmuLib|Include/Library/MmuLib.h
+# MU_CHANGE [END]
 
   ##  @libraryclass  Provides services to generate Entropy using a TRNG.
   #
@@ -315,7 +320,6 @@
 
   ##  @libraryclass  Provides services to log the SMI handler registration.
   SmiHandlerProfileLib|Include/Library/SmiHandlerProfileLib.h
-
   ##  @libraryclass  Provides function to support TDX processing.
   TdxLib|Include/Library/TdxLib.h
 

MdePkg/MdePkg.dsc

@@ -136,6 +136,8 @@
   MdePkg/Library/CcProbeLibNull/CcProbeLibNull.inf
   MdePkg/Library/SmmCpuRendezvousLibNull/SmmCpuRendezvousLibNull.inf
 
+  MdePkg/Library/BaseMmuLibNull/BaseMmuLibNull.inf      ## MU_CHANGE
+
 [Components.IA32, Components.X64, Components.ARM, Components.AARCH64]
   #
   # Add UEFI Target Based Unit Tests