ArmVirtPkg/ArmVirtMemoryInitPeiLib: handle memory above 4 GB on 32-bit ARM

On 32-bit ARM, split system memory into a region below (and up to) 4 GB
and a region above 4 GB. This is necessary to get the DXE core to consider
the former as the resource descriptor that describes the primary memory
region that also covers the PHIT region.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18427 6f19259b-4bc3-4df7-8a09-765794883524

ArmVirtPkg/Library/ArmVirtMemoryInitPeiLib/ArmVirtMemoryInitPeiLib.c

@@ -56,6 +56,7 @@ MemoryPeim (
   )
 {
   EFI_RESOURCE_ATTRIBUTE_TYPE ResourceAttributes;
+  UINT64                      SystemMemoryTop;
 
   // Ensure PcdSystemMemorySize has been set
   ASSERT (PcdGet64 (PcdSystemMemorySize) != 0);
@@ -73,12 +74,30 @@ MemoryPeim (
       EFI_RESOURCE_ATTRIBUTE_TESTED
   );
 
-  BuildResourceDescriptorHob (
-      EFI_RESOURCE_SYSTEM_MEMORY,
-      ResourceAttributes,
-      PcdGet64 (PcdSystemMemoryBase),
-      PcdGet64 (PcdSystemMemorySize)
-  );
+  SystemMemoryTop = PcdGet64 (PcdSystemMemoryBase) +
+                    PcdGet64 (PcdSystemMemorySize);
+
+  if (SystemMemoryTop - 1 > MAX_ADDRESS) {
+    BuildResourceDescriptorHob (
+        EFI_RESOURCE_SYSTEM_MEMORY,
+        ResourceAttributes,
+        PcdGet64 (PcdSystemMemoryBase),
+        (UINT64)MAX_ADDRESS - PcdGet64 (PcdSystemMemoryBase) + 1
+        );
+    BuildResourceDescriptorHob (
+        EFI_RESOURCE_SYSTEM_MEMORY,
+        ResourceAttributes,
+        (UINT64)MAX_ADDRESS + 1,
+        SystemMemoryTop - MAX_ADDRESS - 1
+        );
+  } else {
+    BuildResourceDescriptorHob (
+        EFI_RESOURCE_SYSTEM_MEMORY,
+        ResourceAttributes,
+        PcdGet64 (PcdSystemMemoryBase),
+        PcdGet64 (PcdSystemMemorySize)
+        );
+  }
 
   //
   // When running under virtualization, the PI/UEFI memory region may be