MdeModulePkg DxeIpl: Add stack NX support

This feature is added for UEFI spec that says
"Stack may be marked as non-executable in identity mapped page tables".
A PCD PcdSetNxForStack is added to turn on/off this feature, and it is
FALSE by default.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: "Yao, Jiewen" <Jiewen.yao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18166 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c

@@ -1,7 +1,7 @@
 /** @file
   x64-specifc functionality for DxeLoad.
 
-Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -84,7 +84,13 @@ HandOffToDxeCore (
     //
     // Create page table and save PageMapLevel4 to CR3
     //
-    PageTables = CreateIdentityMappingPageTables ();
+    PageTables = CreateIdentityMappingPageTables ((EFI_PHYSICAL_ADDRESS) (UINTN) BaseOfStack, STACK_SIZE);
+  } else {
+    //
+    // Set NX for stack feature also require PcdDxeIplBuildPageTables be TRUE
+    // for the DxeIpl and the DxeCore are both X64.
+    //
+    ASSERT (PcdGetBool (PcdSetNxForStack) == FALSE);
   }
   
   //