MdeModulePkg: Always Initialize Separate Exception Stacks

os-d · mergify[bot] · commit cec2c6bbccf7 · 2025-10-23T00:57:59.000Z
Following the APs now always initializing separate exception
stacks, this commit always initializes a separate exception
stack for the BSP as well. Previously, this was only enabled
when PcdCpuStackGuard was set.

However, even when a stack guard page is not present,
stack overflows can still occur and corrupt the stack; if an
exception is taken here, it is still valuable to have a separate
exception stack for sanity.

Signed-off-by: Oliver Smith-Denny &lt;osde@microsoft.com&gt;
diff --git a/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c b/MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c
@@ -259,12 +259,10 @@ DxeMain (
   ASSERT_EFI_ERROR (Status);
 
   //
-  // Setup Stack Guard
+  // Setup Exception Stack
   //
-  if (PcdGetBool (PcdCpuStackGuard)) {
-    Status = InitializeSeparateExceptionStacks (NULL, NULL);
-    ASSERT_EFI_ERROR (Status);
-  }
+  Status = InitializeSeparateExceptionStacks (NULL, NULL);
+  ASSERT_EFI_ERROR (Status);
 
   //
   // Initialize Debug Agent to support source level debug in DXE phase
