[edk2-devel] [RFC PATCH 09/10] MdeModulePkg/DxeIpl: Use memory attribute PPI to remap the stack NX
Ard Biesheuvel
ardb at kernel.org
Thu May 25 14:30:40 UTC 2023
If the associated PCD is set to TRUE, use the memory attribute PPI to
remap the stack non-executable. This provides a generic method for doing
so, which will be used by ARM and AArch64 as well once they move to the
generic DxeIpl handoff implementation.
Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
MdeModulePkg/Core/DxeIplPeim/DxeHandoff.c | 29 ++++++++++++++++++--
MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf | 5 +++-
2 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeHandoff.c b/MdeModulePkg/Core/DxeIplPeim/DxeHandoff.c
index a0f85ebea56e6cba..22caabb02840ba88 100644
--- a/MdeModulePkg/Core/DxeIplPeim/DxeHandoff.c
+++ b/MdeModulePkg/Core/DxeIplPeim/DxeHandoff.c
@@ -2,12 +2,15 @@
Generic version of arch-specific functionality for DxeLoad.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2023, Google, LLC. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "DxeIpl.h"
+#include <Ppi/MemoryAttribute.h>
+
/**
Transfers control to DxeCore.
@@ -25,9 +28,10 @@ HandOffToDxeCore (
IN EFI_PEI_HOB_POINTERS HobList
)
{
- VOID *BaseOfStack;
- VOID *TopOfStack;
- EFI_STATUS Status;
+ VOID *BaseOfStack;
+ VOID *TopOfStack;
+ EFI_STATUS Status;
+ EDKII_MEMORY_ATTRIBUTE_PPI *MemoryPpi;
//
// Allocate 128KB for the Stack
@@ -35,6 +39,25 @@ HandOffToDxeCore (
BaseOfStack = AllocatePages (EFI_SIZE_TO_PAGES (STACK_SIZE));
ASSERT (BaseOfStack != NULL);
+ if (PcdGetBool (PcdSetNxForStack)) {
+ Status = PeiServicesLocatePpi (
+ &gEdkiiMemoryAttributePpiGuid,
+ 0,
+ NULL,
+ (VOID **)&MemoryPpi
+ );
+ ASSERT_EFI_ERROR (Status);
+
+ Status = MemoryPpi->SetPermissions (
+ MemoryPpi,
+ (UINTN)BaseOfStack,
+ STACK_SIZE,
+ EFI_MEMORY_XP,
+ 0
+ );
+ ASSERT_EFI_ERROR (Status);
+ }
+
//
// Compute the top of the stack we were allocated. Pre-allocate a UINTN
// for safety.
diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
index 60c998be6c1bad01..7126a96d8378d1f8 100644
--- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
+++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
@@ -91,6 +91,7 @@ [Ppis]
gEfiPeiMemoryDiscoveredPpiGuid ## SOMETIMES_CONSUMES
gEdkiiPeiBootInCapsuleOnDiskModePpiGuid ## SOMETIMES_CONSUMES
gEdkiiPeiCapsuleOnDiskPpiGuid ## SOMETIMES_CONSUMES # Consumed on firmware update boot path
+ gEdkiiMemoryAttributePpiGuid ## SOMETIMES_CONSUMES
[Guids]
## SOMETIMES_CONSUMES ## Variable:L"MemoryTypeInformation"
@@ -117,10 +118,12 @@ [Pcd.IA32,Pcd.X64]
gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize ## CONSUMES
[Pcd.IA32,Pcd.X64,Pcd.ARM,Pcd.AARCH64]
- gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack ## SOMETIMES_CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy ## SOMETIMES_CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## SOMETIMES_CONSUMES
+[Pcd]
+ gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack ## SOMETIMES_CONSUMES
+
[Depex]
gEfiPeiLoadFilePpiGuid AND gEfiPeiMasterBootModePpiGuid
--
2.39.2
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