MdeModulePkg/DxeIpl: support more NX related PCDs

[mirror_edk2.git] / MdeModulePkg / Core / DxeIplPeim / X64 / VirtualMemory.c

diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
index 496e21991347c0a6bbe8d3cea6ee1a3d88493f34..cf3c3f94d864130d1d4ac545ad699a6059a64875 100644 (file)
--- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
+++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
@@ -106,6 +106,62 @@ IsNullDetectionEnabled (
   return ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) != 0);\r
 }\r
 \r
+/**\r
+  The function will check if Execute Disable Bit is available.\r
+\r
+  @retval TRUE      Execute Disable Bit is available.\r
+  @retval FALSE     Execute Disable Bit is not available.\r
+\r
+**/\r
+BOOLEAN\r
+IsExecuteDisableBitAvailable (\r
+  VOID\r
+  )\r
+{\r
+  UINT32            RegEax;\r
+  UINT32            RegEdx;\r
+  BOOLEAN           Available;\r
+\r
+  Available = FALSE;\r
+  AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);\r
+  if (RegEax >= 0x80000001) {\r
+    AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx);\r
+    if ((RegEdx & BIT20) != 0) {\r
+      //\r
+      // Bit 20: Execute Disable Bit available.\r
+      //\r
+      Available = TRUE;\r
+    }\r
+  }\r
+\r
+  return Available;\r
+}\r
+\r
+/**\r
+  Check if Execute Disable Bit (IA32_EFER.NXE) should be enabled or not.\r
+\r
+  @retval TRUE    IA32_EFER.NXE should be enabled.\r
+  @retval FALSE   IA32_EFER.NXE should not be enabled.\r
+\r
+**/\r
+BOOLEAN\r
+IsEnableNonExecNeeded (\r
+  VOID\r
+  )\r
+{\r
+  if (!IsExecuteDisableBitAvailable ()) {\r
+    return FALSE;\r
+  }\r
+\r
+  //\r
+  // XD flag (BIT63) in page table entry is only valid if IA32_EFER.NXE is set.\r
+  // Features controlled by Following PCDs need this feature to be enabled.\r
+  //\r
+  return (PcdGetBool (PcdSetNxForStack) ||\r
+          PcdGet64 (PcdDxeNxMemoryProtectionPolicy) != 0 ||\r
+          PcdGet32 (PcdImageProtectionPolicy) != 0);\r
+}\r
+\r
 /**\r
   Enable Execute Disable Bit.\r
 \r
@@ -755,7 +811,10 @@ CreateIdentityMappingPageTables (
   //\r
   EnablePageTableProtection ((UINTN)PageMap, TRUE);\r
 \r
-  if (PcdGetBool (PcdSetNxForStack)) {\r
+  //\r
+  // Set IA32_EFER.NXE if necessary.\r
+  //\r
+  if (IsEnableNonExecNeeded ()) {\r
     EnableExecuteDisableBit ();\r
   }\r
 \r