MdeModulePkg: Clarify usage of PcdHeapGuardPropertyMask

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 8efad57766a02ac81110bffbccc1c5ab81c2da38..d134ec798a4965ae35fa8ffe88db350a3a4a989f 100644 (file)
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -939,13 +939,17 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType|0x0|UINT64|0x30001053\r
 \r
   ## This mask is to control Heap Guard behavior.\r
+  # Note that due to the limit of pool memory implementation and the alignment\r
+  # requirement of UEFI spec, BIT7 is a try-best setting which cannot guarantee\r
+  # that the returned pool is exactly adjacent to head guard page or tail guard\r
+  # page.\r
   #   BIT0 - Enable UEFI page guard.<BR>\r
   #   BIT1 - Enable UEFI pool guard.<BR>\r
   #   BIT2 - Enable SMM page guard.<BR>\r
   #   BIT3 - Enable SMM pool guard.<BR>\r
   #   BIT7 - The direction of Guard Page for Pool Guard.\r
-  #          0 - The returned pool is adjacent to the bottom guard page.<BR>\r
-  #          1 - The returned pool is adjacent to the top guard page.<BR>\r
+  #          0 - The returned pool is near the tail guard page.<BR>\r
+  #          1 - The returned pool is near the head guard page.<BR>\r
   # @Prompt The Heap Guard feature mask\r
   gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask|0x0|UINT8|0x30001054\r
 \r

diff --git a/MdeModulePkg/MdeModulePkg.uni b/MdeModulePkg/MdeModulePkg.uni
index 43dd5103be9bfcf6eeb797b55b18baa1b2855a6e..fb45ccb76865fac97ea37a7f357dc7884e441caa 100644 (file)
--- a/MdeModulePkg/MdeModulePkg.uni
+++ b/MdeModulePkg/MdeModulePkg.uni
@@ -1196,13 +1196,17 @@
 #string STR_gEfiMdeModulePkgTokenSpaceGuid_PcdHeapGuardPropertyMask_PROMPT  #language en-US "The Heap Guard feature mask"\r
 \r
 #string STR_gEfiMdeModulePkgTokenSpaceGuid_PcdHeapGuardPropertyMask_HELP    #language en-US "This mask is to control Heap Guard behavior.\n"\r
+                                                                                            "Note that due to the limit of pool memory implementation and the alignment\n"\r
+                                                                                            "requirement of UEFI spec, BIT7 is a try-best setting which cannot guarantee\n"\r
+                                                                                            "that the returned pool is exactly adjacent to head guard page or tail guard\n"\r
+                                                                                            "page.\n"\r
                                                                                             "   BIT0 - Enable UEFI page guard.<BR>\n"\r
                                                                                             "   BIT1 - Enable UEFI pool guard.<BR>\n"\r
                                                                                             "   BIT2 - Enable SMM page guard.<BR>\n"\r
                                                                                             "   BIT3 - Enable SMM pool guard.<BR>\n"\r
                                                                                             "   BIT7 - The direction of Guard Page for Pool Guard.\n"\r
-                                                                                            "          0 - The returned pool is adjacent to the bottom guard page.<BR>\n"\r
-                                                                                            "          1 - The returned pool is adjacent to the top guard page.<BR>"\r
+                                                                                            "          0 - The returned pool is near the tail guard page.<BR>\n"\r
+                                                                                            "          1 - The returned pool is near the head guard page.<BR>"\r
 \r
 #string STR_gEfiMdeModulePkgTokenSpaceGuid_PcdCpuStackGuard_PROMPT  #language en-US "Enable UEFI Stack Guard"\r
 \r