MdeModulePkg/MdeModulePkg.dec: clarify Heap Guard usage

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 037b16e2d0f4a8df8bad9a171ef9a87fc838d6ac..491fb27663653ce71ec72bb1a318d3495b614fef 100644 (file)
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -893,6 +893,12 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack|0x5AA55AA5|UINT32|0x30001051\r
 \r
   ## Indicates which type allocation need guard page.\r
+  #\r
+  # If a bit is set, a head guard page and a tail guard page will be added just\r
+  # before and after corresponding type of pages allocated if there's enough\r
+  # free pages for all of them. The page allocation for the type related to\r
+  # cleared bits keeps the same as ususal.\r
+  #\r
   # Below is bit mask for this PCD: (Order is same as UEFI spec)<BR>\r
   #  EfiReservedMemoryType             0x0000000000000001<BR>\r
   #  EfiLoaderCode                     0x0000000000000002<BR>\r
@@ -916,6 +922,12 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPageType|0x0|UINT64|0x30001052\r
 \r
   ## Indicates which type allocation need guard page.\r
+  #\r
+  # If a bit is set, a head guard page and a tail guard page will be added just\r
+  # before and after corresponding type of pages which the allocated pool occupies,\r
+  # if there's enough free memory for all of them. The pool allocation for the\r
+  # type related to cleared bits keeps the same as ususal.\r
+  #\r
   # Below is bit mask for this PCD: (Order is same as UEFI spec)<BR>\r
   #  EfiReservedMemoryType             0x0000000000000001<BR>\r
   #  EfiLoaderCode                     0x0000000000000002<BR>\r