From 760614b0c5e23b4d71521c8805a40720b399a20d Mon Sep 17 00:00:00 2001
From: Mikhail Krichanov <mikhailkrichanov@gmail.com>
Date: Wed, 25 Sep 2024 09:40:03 +0300
Subject: [PATCH] SysCall: Fixed page fault for ARM.

---
 .../Core/Dxe/SysCall/ARM/InitializeMsr.c        | 17 +++++++++++++----
 .../Core/Dxe/SysCall/SupportedProtocols.c       |  6 +++---
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c b/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c
index 8ffd808742..d208c9e0fe 100644
--- a/MdeModulePkg/Core/Dxe/SysCall/ARM/InitializeMsr.c
+++ b/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.
diff --git a/MdeModulePkg/Core/Dxe/SysCall/SupportedProtocols.c b/MdeModulePkg/Core/Dxe/SysCall/SupportedProtocols.c
index a04c7aa92c..4da58f9839 100644
--- a/MdeModulePkg/Core/Dxe/SysCall/SupportedProtocols.c
+++ b/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.