MdeModulePkg/Core: fix feature conflict between NX and heap guard

[mirror_edk2.git] / MdeModulePkg / Core / Dxe / Mem / HeapGuard.c

diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
index 0f035043e15a2ead446f9b8d0de89f08a7df2dff..d7906e08c53c4f795aaf05fe5b0207eb1b1d84e7 100644 (file)
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -728,6 +728,20 @@ IsPageTypeToGuard (
   return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);\r
 }\r
 \r
+/**\r
+  Check to see if the heap guard is enabled for page and/or pool allocation.\r
+\r
+  @return TRUE/FALSE.\r
+**/\r
+BOOLEAN\r
+IsHeapGuardEnabled (\r
+  VOID\r
+  )\r
+{\r
+  return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages,\r
+                              GUARD_HEAP_TYPE_POOL|GUARD_HEAP_TYPE_PAGE);\r
+}\r
+\r
 /**\r
   Set head Guard and tail Guard for the given memory range.\r
 \r
@@ -1127,8 +1141,22 @@ CoreConvertPagesWithGuard (
   IN EFI_MEMORY_TYPE  NewType\r
   )\r
 {\r
+  UINT64  OldStart;\r
+  UINTN   OldPages;\r
+\r
   if (NewType == EfiConventionalMemory) {\r
+    OldStart = Start;\r
+    OldPages = NumberOfPages;\r
+\r
     AdjustMemoryF (&Start, &NumberOfPages);\r
+    //\r
+    // It's safe to unset Guard page inside memory lock because there should\r
+    // be no memory allocation occurred in updating memory page attribute at\r
+    // this point. And unsetting Guard page before free will prevent Guard\r
+    // page just freed back to pool from being allocated right away before\r
+    // marking it usable (from non-present to present).\r
+    //\r
+    UnsetGuardForMemory (OldStart, OldPages);\r
     if (NumberOfPages == 0) {\r
       return EFI_SUCCESS;\r
     }\r