SysCall: Fixed page fault for ARM.

MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c

@@ -11,6 +11,7 @@
 #include "DxeMain.h"
 
 STATIC UINTN  mCoreSp;
+extern UINTN  gUartBaseAddress;
 
 EFI_STATUS
 EFIAPI
@@ -64,6 +65,12 @@ SysCallBootService (
   // All remaining arguments are on User Stack.
   //
   CopyMem ((VOID *)((UINTN)Physical + 5 * sizeof (UINTN)), (VOID *)UserRsp, 4 * sizeof (UINTN));
+
+  SetUefiImageMemoryAttributes (
+    gUartBaseAddress,
+    EFI_PAGE_SIZE,
+    EFI_MEMORY_XP
+    );
   ForbidSupervisorAccessToUserMemory ();
 
   Status = CallBootService (
@@ -72,6 +79,12 @@ SysCallBootService (
              (RING3_STACK *)(UINTN)Physical
              );
 
+  SetUefiImageMemoryAttributes (
+    gUartBaseAddress,
+    EFI_PAGE_SIZE,
+    EFI_MEMORY_XP | EFI_MEMORY_USER
+    );
+
   CoreFreePages (Physical, EFI_SIZE_TO_PAGES (9 * sizeof (UINTN)));
 
   return Status;
@@ -84,10 +97,6 @@ InitializeMsr (
   IN     UINTN                   NumberOfEntries
   )
 {
-  //
-  // TODO: EFI_CONFIGURATION_TABLE, HOB_DATA, Uart are accessible to User.
-  // Fix PageTable initialization.
-  //
   if (ArmHasPan ()) {
     //
     // Enable Privileged Access Never feature.

MdeModulePkg/Core/Dxe/SysCall/SupportedProtocols.c

@@ -13,7 +13,7 @@ EFI_FILE_PROTOCOL                mRing3FileProtocol;
 
 EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *mRing3SimpleFileSystemPointer;
 
-#if defined (MDE_CPU_AARCH64)
+#if defined (MDE_CPU_AARCH64) || defined (MDE_CPU_ARM)
 extern UINTN  gUartBaseAddress;
 #endif
 
@@ -73,7 +73,7 @@ GoToRing3 (
       EFI_MEMORY_XP | EFI_MEMORY_USER
       );
   }
-#elif defined (MDE_CPU_AARCH64)
+#elif defined (MDE_CPU_AARCH64) || defined (MDE_CPU_ARM)
   //
   // Necessary fix for DEBUG printings.
   //
@@ -93,7 +93,7 @@ GoToRing3 (
       EFI_MEMORY_XP
       );
   }
-#elif defined (MDE_CPU_AARCH64)
+#elif defined (MDE_CPU_AARCH64) || defined (MDE_CPU_ARM)
   //
   // Problem 2: Uart memory maped page is not allocated at the very beginnig
   // and can be used for translation table later.