You may need also add PcdNullPointerDetectionPropertyMask prompt and help into 
the MdeModulePkg.uni.


Thanks,
Star
-----Original Message-----
From: Wang, Jian J 
Sent: Thursday, September 21, 2017 1:20 PM
To: [email protected]
Cc: Wang, Jian J <[email protected]>; Zeng, Star <[email protected]>; 
Dong, Eric <[email protected]>; Laszlo Ersek <[email protected]>; Yao, Jiewen 
<[email protected]>; Kinney, Michael D <[email protected]>; Justen, 
Jordan L <[email protected]>; Wolman, Ayellet <[email protected]>
Subject: [PATCH v2 1/6] MdeModulePkg/MdeModulePkg.dec: Add NULL pointer 
detection PCD

From: "Wang, Jian J" <[email protected]>

PCD PcdNullPointerDetectionPropertyMask is a bitmask used to control the NULL 
address detection functionality in code for different phases.

If enabled, accessing NULL address in UEFI or SMM code can be caught as a page 
fault exception.

    BIT0    - Enable NULL pointer detection for UEFI.
    BIT1    - Enable NULL pointer detection for SMM.
    BIT2..6 - Reserved for future uses.
    BIT7    - Disable NULL pointer detection just after EndOfDxe. This is a
              workaround for those unsolvable NULL access issues in
              OptionROM, boot loader, etc. It can also help to avoid
              unnecessary exception caused by legacy memory (0-4095) access
              after EndOfDxe, such as Windows 7 boot on Qemu.

Cc: Star Zeng <[email protected]>
Cc: Eric Dong <[email protected]>
Cc: Laszlo Ersek <[email protected]>
Cc: Jiewen Yao <[email protected]>
Cc: Michael Kinney <[email protected]>
Cc: Jordan Justen <[email protected]>
Cc: Ayellet Wolman <[email protected]>
Suggested-by: Ayellet Wolman <[email protected]>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <[email protected]>
---
 MdeModulePkg/MdeModulePkg.dec | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec 
index 403a66a5ad..3f90b8d7e6 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -863,6 +863,19 @@
   # @ValidList  0x80000006 | 0x03058002
   
gEfiMdeModulePkgTokenSpaceGuid.PcdErrorCodeSetVariable|0x03058002|UINT32|0x30001040
 
+  ## Mask to control the NULL address detection in code for different phases.
+  #  If enabled, accessing NULL address in UEFI or SMM code can be 
caught.<BR><BR>
+  #    BIT0    - Enable NULL pointer detection for UEFI.<BR>
+  #    BIT1    - Enable NULL pointer detection for SMM.<BR>
+  #    BIT2..6 - Reserved for future uses.<BR>
+  #    BIT7    - Disable NULL pointer detection just after EndOfDxe. <BR>
+  #              This is a workaround for those unsolvable NULL access issues 
in
+  #              OptionROM, boot loader, etc. It can also help to avoid 
unnecessary
+  #              exception caused by legacy memory (0-4095) access after 
EndOfDxe,
+  #              such as Windows 7 boot on Qemu.<BR>
+  # @Prompt Enable NULL address detection.
+  
+ gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask|0x0
+ |UINT8|0x30001050
+
 [PcdsFixedAtBuild, PcdsPatchableInModule]
   ## Dynamic type PCD can be registered callback function for Pcd setting 
action.
   #  PcdMaxPeiPcdCallBackNumberPerPcdEntry indicates the maximum number of 
callback function
--
2.14.1.windows.1

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