[edk2] [PATCH v2 6/6] MdeModulePkg/DxeIpl: Enable paging for heap guard

[Jian J Wang]

Heap guard feature needs paging to work properly. 64-bit BIOS uses
PcdDxeIplBuildPageTables to control the page table setup. 32-bit BIOS
has to check heap guard feature to decide enabling paging or not.

Cc: Star Zeng <star.z...@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wol...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
---
 MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf         |  1 +
 MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c | 29 ++++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf 
b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
index c54afe4aa6..1c48f80a76 100644
--- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
+++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
@@ -115,6 +115,7 @@
 [Pcd.IA32,Pcd.X64]
   gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable                      ## 
SOMETIMES_CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask    ## 
CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask               ## 
CONSUMES
 
 [Pcd.IA32,Pcd.X64,Pcd.ARM,Pcd.AARCH64]
   gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack               ## 
SOMETIMES_CONSUMES
diff --git a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c 
b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
index 1957326caf..306d7ec804 100644
--- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
+++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
@@ -209,6 +209,33 @@ IsExecuteDisableBitAvailable (
   return Available;
 }
 
+/**
+  The function will check if page table should be setup or not.
+
+  @retval TRUE      Page table should be created.
+  @retval FALSE     Page table should not be created.
+
+**/
+BOOLEAN
+ToBuildPageTable (
+  VOID
+  )
+{
+  if (!IsIa32PaeSupport ()) {
+    return FALSE;
+  }
+
+  if (PcdGet8 (PcdHeapGuardPropertyMask) != 0) {
+    return TRUE;
+  }
+
+  if (PcdGetBool (PcdSetNxForStack) && IsExecuteDisableBitAvailable ()) {
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
 /**
    Transfers control to DxeCore.
 
@@ -379,7 +406,7 @@ HandOffToDxeCore (
     TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 
CPU_STACK_ALIGNMENT);
 
     PageTables = 0;
-    BuildPageTablesIa32Pae = (BOOLEAN) (PcdGetBool (PcdSetNxForStack) && 
IsIa32PaeSupport () && IsExecuteDisableBitAvailable ());
+    BuildPageTablesIa32Pae = ToBuildPageTable ();
     if (BuildPageTablesIa32Pae) {
       PageTables = Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE);
       EnableExecuteDisableBit ();
-- 
2.14.1.windows.1

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