ArmPkg/CpuPei: Implement the memory attributes PPI

Implement the newly defined PPI that permits the PEI core and DXE IPL to
manage memory permissions on ranges of DRAM, for doing things like
mapping the stack non-executable, or granting executable permissions to
shadowed PEIMs.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>

ArmPkg/Drivers/CpuPei/CpuPei.c

@@ -3,6 +3,7 @@
 Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
 Copyright (c) 2011 Hewlett Packard Corporation. All rights reserved.<BR>
 Copyright (c) 2011-2013, ARM Limited. All rights reserved.<BR>
+Copyright (c) 2023, Google, LLC. All rights reserved.<BR>
 
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -24,6 +25,7 @@ Abstract:
 // The protocols, PPI and GUID definitions for this module
 //
 #include <Ppi/ArmMpCoreInfo.h>
+#include <Ppi/MemoryAttribute.h>
 
 //
 // The Library classes this module consumes
@@ -34,6 +36,77 @@ Abstract:
 #include <Library/PcdLib.h>
 #include <Library/HobLib.h>
 #include <Library/ArmLib.h>
+#include <Library/ArmMmuLib.h>
+
+/**
+  Set the requested memory permission attributes on a region of memory.
+
+  BaseAddress and Length must be aligned to EFI_PAGE_SIZE.
+
+  Attributes must contain a combination of EFI_MEMORY_RP, EFI_MEMORY_RO and
+  EFI_MEMORY_XP, and specifies the attributes that must be set for the
+  region in question. Attributes that are omitted will be cleared from the
+  region only if they are set in AttributeMask.
+
+  AttributeMask must contain a combination of EFI_MEMORY_RP, EFI_MEMORY_RO and
+  EFI_MEMORY_XP, and specifies the attributes that the call will operate on.
+  AttributeMask must not be 0x0, and must contain at least the bits set in
+  Attributes.
+
+  @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]  Attributes        Memory attributes to set or clear.
+  @param[in]  AttributeMask     Mask of memory attributes to operate on.
+
+  @retval EFI_SUCCESS           The attributes were set for the memory region.
+  @retval EFI_INVALID_PARAMETER Length is zero.
+                                AttributeMask is zero.
+                                AttributeMask lacks bits set in Attributes.
+                                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.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+SetMemoryPermissions (
+  IN  EDKII_MEMORY_ATTRIBUTE_PPI  *This,
+  IN  EFI_PHYSICAL_ADDRESS        BaseAddress,
+  IN  UINT64                      Length,
+  IN  UINT64                      Attributes,
+  IN  UINT64                      AttributeMask
+  )
+{
+  if ((Length == 0) ||
+      (AttributeMask == 0) ||
+      ((AttributeMask & (EFI_MEMORY_RP | EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) ||
+      ((Attributes & ~AttributeMask) != 0) ||
+      (((BaseAddress | Length) & EFI_PAGE_MASK) != 0))
+  {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  return ArmSetMemoryAttributes (BaseAddress, Length, Attributes, AttributeMask);
+}
+
+STATIC CONST EDKII_MEMORY_ATTRIBUTE_PPI  mMemoryAttributePpi = {
+  SetMemoryPermissions
+};
+
+STATIC CONST EFI_PEI_PPI_DESCRIPTOR  mMemoryAttributePpiDesc = {
+  (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
+  &gEdkiiMemoryAttributePpiGuid,
+  (VOID *)&mMemoryAttributePpi
+};
 
 /*++
 
@@ -79,5 +152,8 @@ InitializeCpuPeim (
     }
   }
 
+  Status = PeiServicesInstallPpi (&mMemoryAttributePpiDesc);
+  ASSERT_EFI_ERROR (Status);
+
   return EFI_SUCCESS;
 }

ArmPkg/Drivers/CpuPei/CpuPei.inf

@@ -3,6 +3,7 @@
 #
 # This module provides platform specific function to detect boot mode.
 # Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2023, Google, LLC. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -28,6 +29,7 @@
   CpuPei.c
 
 [Packages]
+  MdeModulePkg/MdeModulePkg.dec
   MdePkg/MdePkg.dec
   EmbeddedPkg/EmbeddedPkg.dec
   ArmPkg/ArmPkg.dec
@@ -37,9 +39,11 @@
   DebugLib
   HobLib
   ArmLib
+  ArmMmuLib
 
 [Ppis]
   gArmMpCoreInfoPpiGuid
+  gEdkiiMemoryAttributePpiGuid
 
 [Guids]
   gArmMpCoreInfoGuid