From eafbf588760c289b7f54a4771b39af0ccfe8cf59 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Wed, 10 Dec 2025 21:55:42 +0100
Subject: kapi: extract page_mapper interface

---
 arch/x86_64/src/kapi/memory.cpp | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

(limited to 'arch/x86_64/src/kapi')

diff --git a/arch/x86_64/src/kapi/memory.cpp b/arch/x86_64/src/kapi/memory.cpp
index ed3edef..00b9de3 100644
--- a/arch/x86_64/src/kapi/memory.cpp
+++ b/arch/x86_64/src/kapi/memory.cpp
@@ -13,6 +13,7 @@
 #include "x86_64/memory/page_table.hpp"
 #include "x86_64/memory/page_utilities.hpp"
 #include "x86_64/memory/paging_root.hpp"
+#include "x86_64/memory/recursive_page_mapper.hpp"
 #include "x86_64/memory/region_allocator.hpp"
 #include "x86_64/memory/scoped_mapping.hpp"
 
@@ -29,6 +30,8 @@ namespace teachos::memory
   {
     // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
     auto constinit allocator = static_cast<frame_allocator *>(nullptr);
+    // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
+    auto constinit mapper = static_cast<page_mapper *>(nullptr);
 
     constexpr auto static unused_page_address = linear_address{0x0000'7fff'cafe'faceuz};
     constexpr auto static recursive_page_map_index = x86_64::page_table::entry_count - 2;
@@ -70,7 +73,7 @@ namespace teachos::memory
 
       auto page = page::containing(unused_page_address);
 
-      auto temporary_mapper = scoped_mapping{page, allocator};
+      auto temporary_mapper = scoped_mapping{page};
       auto new_pml4_frame = allocator.allocate();
 
       auto pml4 = std::construct_at(temporary_mapper.map_as<page_table>(*new_pml4_frame, entry_flags::writable));
@@ -124,6 +127,15 @@ namespace teachos::memory
     return *allocator;
   }
 
+  auto active_mapper() -> page_mapper &
+  {
+    if (!mapper)
+    {
+      system::panic("[x86_64] The page mapper has not been set you.");
+    }
+    return *mapper;
+  }
+
   auto init() -> void
   {
     auto static constinit is_initialized = std::atomic_flag{};
@@ -132,14 +144,19 @@ namespace teachos::memory
       system::panic("[x86_64] Memory management has already been initialized.");
     }
 
-    auto allocator = create_early_frame_allocator();
     enable_cpu_protections();
 
-    auto allocation_buffer = x86_64::buffered_allocator<4>{&allocator};
+    auto early_allocator = create_early_frame_allocator();
+    auto allocation_buffer = x86_64::buffered_allocator<4>{&early_allocator};
+    allocator = &allocation_buffer;
+
+    auto recursive_mapper = x86_64::recursive_page_mapper{allocation_buffer};
+    mapper = &recursive_mapper;
+
     auto new_pml4_frame = inject_faux_pml4(allocation_buffer);
 
-    auto mapper = x86_64::kernel_mapper{allocation_buffer, boot::bootstrap_information.mbi};
-    mapper.remap_kernel();
+    auto kernel_mapper = x86_64::kernel_mapper{boot::bootstrap_information.mbi};
+    kernel_mapper.remap_kernel();
     cio::println("[x86_64:MEM] prepared new kernel image page maps.");
 
     auto cr3 = cpu::x86_64::cr3::read();
@@ -149,6 +166,8 @@ namespace teachos::memory
     // remap_heap(heap::KERNEL_HEAP_START, heap::KERNEL_HEAP_SIZE);
     // video::vga::text::write("Heap remapping successful", video::vga::text::common_attributes::green_on_black);
     // video::vga::text::newline();
+    mapper = nullptr;
+    allocator = nullptr;
   }
 
 }  // namespace teachos::memory
-- 
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