Re: [PATCH 6/6] MdeModulePkg/BootScriptExecutorDxe: remove NX attr for FfsBuffer

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com>

-----Original Message-----
From: Wang, Jian J 
Sent: Monday, January 15, 2018 4:55 PM
To: edk2-devel@lists.01.org
Cc: Yao, Jiewen <jiewen.yao@intel.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Dong, Eric <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH 6/6] MdeModulePkg/BootScriptExecutorDxe: remove NX attr for FfsBuffer

If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory of EfiReservedMemoryType, the BIOS will hang at a page fault exception triggered by BootScriptExecutorDxe.

The root cause is that this driver will allocate memory of EfiReservedMemoryType and relocate itself into this new memory. Since EfiReservedMemoryType of memory is marked non-executable, re-start this driver after relocation will cause exception. The fix is removing the NX attribute after memory allocation.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 .../Acpi/BootScriptExecutorDxe/BootScriptExecutorDxe.inf   |  1 +
 .../Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.c   | 14 ++++++++++++++
 .../Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.h   |  1 +
 3 files changed, 16 insertions(+)

diff --git a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/BootScriptExecutorDxe.inf b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/BootScriptExecutorDxe.inf
index 29af7f55ec..aac132122c 100644
--- a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/BootScriptExecutorDxe.inf
+++ b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/BootScriptExecut
+++ orDxe.inf
@@ -68,6 +68,7 @@
   LockBoxLib
   CpuExceptionHandlerLib
   DevicePathLib
+  DxeServicesTableLib
 
 [Guids]
   gEfiBootScriptExecutorVariableGuid    ## PRODUCES ## UNDEFINED # SaveLockBox
diff --git a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.c b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.c
index 4545d6e581..263a282188 100644
--- a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.c
+++ b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.c
@@ -273,6 +273,7 @@ ReadyToLockEventNotify (
   UINTN                                         Pages;
   EFI_PHYSICAL_ADDRESS                          FfsBuffer;
   PE_COFF_LOADER_IMAGE_CONTEXT                  ImageContext;
+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR               MemDesc;
 
   Status = gBS->LocateProtocol (&gEfiDxeSmmReadyToLockProtocolGuid, NULL, &Interface);
   if (EFI_ERROR (Status)) {
@@ -322,6 +323,19 @@ ReadyToLockEventNotify (
                   &FfsBuffer
                   );
   ASSERT_EFI_ERROR (Status);
+
+  //
+  // Make sure that the buffer can be used to store code.
+  //
+  Status = gDS->GetMemorySpaceDescriptor (FfsBuffer, &MemDesc);  if 
+ (!EFI_ERROR (Status) && (MemDesc.Attributes & EFI_MEMORY_XP) != 0) {
+    gDS->SetMemorySpaceAttributes (
+           FfsBuffer,
+           EFI_PAGES_TO_SIZE (Pages),
+           MemDesc.Attributes & (~EFI_MEMORY_XP)
+           );
+  }
+
   ImageContext.ImageAddress = (PHYSICAL_ADDRESS)(UINTN)FfsBuffer;
   //
   // Align buffer on section boundary
diff --git a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.h b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.h
index 75327569d7..94deae87e6 100644
--- a/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.h
+++ b/MdeModulePkg/Universal/Acpi/BootScriptExecutorDxe/ScriptExecute.h
@@ -38,6 +38,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Library/LockBoxLib.h>
 #include <Library/CpuExceptionHandlerLib.h>
 #include <Library/DevicePathLib.h>
+#include <Library/DxeServicesTableLib.h>
 
 #include <Guid/AcpiS3Context.h>
 #include <Guid/BootScriptExecutorVariable.h>
--
2.15.1.windows.2