From: "Wang, Jian J" <jian.j.w...@intel.com>
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 <star.z...@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Michael Kinney <michael.d.kin...@intel.com>
Cc: Ayellet Wolman <ayellet.wol...@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/MdeModulePkg.dec | 13 +++++++++++++
MdeModulePkg/MdeModulePkg.uni | 13 +++++++++++++
2 files changed, 26 insertions(+)
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index a3c0633ee1..9248d10da8 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -867,6 +867,19 @@
# @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
diff --git a/MdeModulePkg/MdeModulePkg.uni b/MdeModulePkg/MdeModulePkg.uni
index d6015de75f..f8b31694ba 100644
--- a/MdeModulePkg/MdeModulePkg.uni
+++ b/MdeModulePkg/MdeModulePkg.uni
@@ -1127,3 +1127,16 @@
"enabled on AMD processors supporting the Secure
Encrypted Virtualization (SEV) feature.\n"
"This mask should be applied when creating 1:1 virtual to
physical mapping tables."
+#string
STR_gEfiMdeModulePkgTokenSpaceGuid_PcdNullPointerDetectionPropertyMask_PROMPT
#language en-US "Enable NULL pointer detection"
+
+#string
STR_gEfiMdeModulePkgTokenSpaceGuid_PcdNullPointerDetectionPropertyMask_HELP
#language en-US "Mask to control the NULL address detection in code for
different phases.\n"
+
" If enabled, accessing NULL address in UEFI or SMM
code can be caught.\n\n"
+
" BIT0 - Enable NULL pointer detection for UEFI.\n"
+
" BIT1 - Enable NULL pointer detection for SMM.\n"
+
" BIT2..6 - Reserved for future uses.\n"
+
" 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.\n"
+
--
2.14.1.windows.1
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