MdeModulePkg/DxeCore: Filter out all paging capabilities

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

diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index 2034b64cd72d0d4e3c9af9372fa06cfc7f2a5fa1..962ae90d3dd68e48708761bff4610750a20ee9bd 100644 (file)
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -1687,6 +1687,7 @@ CoreGetMemoryMap (
   EFI_GCD_MAP_ENTRY                 MergeGcdMapEntry;\r
   EFI_MEMORY_TYPE                   Type;\r
   EFI_MEMORY_DESCRIPTOR             *MemoryMapStart;\r
+  EFI_MEMORY_DESCRIPTOR             *MemoryMapEnd;\r
 \r
   //\r
   // Make sure the parameters are valid\r
@@ -1896,6 +1897,25 @@ CoreGetMemoryMap (
   //\r
   BufferSize = ((UINT8 *)MemoryMap - (UINT8 *)MemoryMapStart);\r
 \r
+  //\r
+  // Note: Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as really\r
+  //       set attributes and change memory paging attribute accordingly.\r
+  //       But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by\r
+  //       value from Capabilities in GCD memory map. This might cause\r
+  //       boot problems. Clearing all paging related capabilities can\r
+  //       workaround it. Following code is supposed to be removed once\r
+  //       the usage of EFI_MEMORY_DESCRIPTOR.Attribute is clarified in\r
+  //       UEFI spec and adopted by both EDK-II Core and all supported\r
+  //       OSs.\r
+  //\r
+  MemoryMapEnd = MemoryMap;\r
+  MemoryMap = MemoryMapStart;\r
+  while (MemoryMap < MemoryMapEnd) {\r
+    MemoryMap->Attribute &= ~(UINT64)(EFI_MEMORY_RP | EFI_MEMORY_RO |\r
+                                      EFI_MEMORY_XP);\r
+    MemoryMap = NEXT_MEMORY_DESCRIPTOR (MemoryMap, Size);\r
+  }\r
+\r
   Status = EFI_SUCCESS;\r
 \r
 Done:\r