From 11f7c25713c2d313fc7b32b46176b79a2a374df6 Mon Sep 17 00:00:00 2001
From: Aiken Harris <harraiken91@gmail.com>
Date: Mon, 12 Jan 2026 23:03:13 +0100
Subject: [PATCH] Abstract base mapping address retrieval

---
 boot/xtldr/modules/xtos_o/amd64/memory.cc  | 14 ++++++++++++++
 boot/xtldr/modules/xtos_o/i686/memory.cc   | 14 ++++++++++++++
 boot/xtldr/modules/xtos_o/includes/xtos.hh |  1 +
 boot/xtldr/modules/xtos_o/xtos.cc          |  8 ++++----
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/boot/xtldr/modules/xtos_o/amd64/memory.cc b/boot/xtldr/modules/xtos_o/amd64/memory.cc
index 02335aa..c5afa07 100644
--- a/boot/xtldr/modules/xtos_o/amd64/memory.cc
+++ b/boot/xtldr/modules/xtos_o/amd64/memory.cc
@@ -156,6 +156,20 @@ Xtos::EnablePaging(IN PXTBL_PAGE_MAPPING PageMap)
     return STATUS_EFI_SUCCESS;
 }
 
+/**
+ * Returns the base address of the memory mapping.
+ *
+ * @return This routine returns the base address of the memory mapping.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+ULONG_PTR
+Xtos::GetBaseMappingAddress(VOID)
+{
+    return KSEG0_BASE;
+}
+
 /**
  * Maps the page table for hardware layer addess space.
  *
diff --git a/boot/xtldr/modules/xtos_o/i686/memory.cc b/boot/xtldr/modules/xtos_o/i686/memory.cc
index 44ee233..08cf608 100644
--- a/boot/xtldr/modules/xtos_o/i686/memory.cc
+++ b/boot/xtldr/modules/xtos_o/i686/memory.cc
@@ -44,6 +44,20 @@ Xtos::DeterminePagingLevel(IN CONST PWCHAR Parameters)
     return 2;
 }
 
+/**
+ * Returns the base address of the memory mapping.
+ *
+ * @return This routine returns the base address of the memory mapping.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+ULONG_PTR
+Xtos::GetBaseMappingAddress(VOID)
+{
+    return KSEG0_BASE;
+}
+
 /**
  * Builds the actual memory mapping page table and enables paging. This routine exits EFI boot services as well.
  *
diff --git a/boot/xtldr/modules/xtos_o/includes/xtos.hh b/boot/xtldr/modules/xtos_o/includes/xtos.hh
index e917d10..8d4b31e 100644
--- a/boot/xtldr/modules/xtos_o/includes/xtos.hh
+++ b/boot/xtldr/modules/xtos_o/includes/xtos.hh
@@ -35,6 +35,7 @@ class Xtos
     private:
         STATIC XTCDECL ULONG DeterminePagingLevel(IN CONST PWCHAR Parameters);
         STATIC XTCDECL EFI_STATUS EnablePaging(IN PXTBL_PAGE_MAPPING PageMap);
+        STATIC XTCDECL ULONG_PTR GetBaseMappingAddress(VOID);
         STATIC XTCDECL VOID GetDisplayInformation(OUT PSYSTEM_RESOURCE_FRAMEBUFFER FrameBufferResource,
                                                   IN PEFI_PHYSICAL_ADDRESS FrameBufferBase,
                                                   IN PULONG_PTR FrameBufferSize,
diff --git a/boot/xtldr/modules/xtos_o/xtos.cc b/boot/xtldr/modules/xtos_o/xtos.cc
index e720c07..2edc751 100644
--- a/boot/xtldr/modules/xtos_o/xtos.cc
+++ b/boot/xtldr/modules/xtos_o/xtos.cc
@@ -554,7 +554,7 @@ Xtos::LoadModule(IN PEFI_FILE_HANDLE SystemDir,
     }
 
     /* Relocate the PE/COFF image file */
-    Status = PeCoffProtocol->RelocateImage(*ImageContext, KSEG0_BASE + (ULONGLONG)(*ImageContext)->PhysicalAddress);
+    Status = PeCoffProtocol->RelocateImage(*ImageContext, GetBaseMappingAddress() | (ULONGLONG)(*ImageContext)->PhysicalAddress);
     if(Status != STATUS_EFI_SUCCESS)
     {
         /* Unable to relocate the file */
@@ -640,7 +640,7 @@ Xtos::MapMemory(IN OUT PXTBL_PAGE_MAPPING PageMap,
     if(KernelMapping)
     {
         /* Map memory based on kernel base address */
-        BaseAddress = KSEG0_BASE;
+        BaseAddress = GetBaseMappingAddress();
     }
     else
     {
@@ -666,7 +666,7 @@ XTCDECL
 PVOID
 Xtos::PhysicalAddressToVirtual(PVOID PhysicalAddress)
 {
-    return (PVOID)((ULONG_PTR)PhysicalAddress | KSEG0_BASE);
+    return (PVOID)((ULONG_PTR)PhysicalAddress | GetBaseMappingAddress());
 }
 
 /**
@@ -762,7 +762,7 @@ Xtos::RunBootSequence(IN PEFI_FILE_HANDLE BootDir,
     /* Initialize virtual memory mappings */
     XtLdrProtocol->Memory.InitializePageMap(&PageMap, DeterminePagingLevel(Parameters->Parameters), Size4K);
 
-    Status = XtLdrProtocol->Memory.MapEfiMemory(&PageMap, KSEG0_BASE);
+    Status = XtLdrProtocol->Memory.MapEfiMemory(&PageMap, GetBaseMappingAddress());
     if(Status != STATUS_EFI_SUCCESS)
     {
         return Status;