From 55f32173e97fdcf4a45006b66cc4b20329a5c7af Mon Sep 17 00:00:00 2001
From: Fabian Imhof <fabian.imhof@ost.ch>
Date: Sun, 24 Nov 2024 13:10:21 +0000
Subject: implement basic heap and remap it

---
 arch/x86_64/src/memory/main.cpp | 47 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 arch/x86_64/src/memory/main.cpp

(limited to 'arch/x86_64/src/memory/main.cpp')

diff --git a/arch/x86_64/src/memory/main.cpp b/arch/x86_64/src/memory/main.cpp
new file mode 100644
index 0000000..ce07115
--- /dev/null
+++ b/arch/x86_64/src/memory/main.cpp
@@ -0,0 +1,47 @@
+#include "arch/memory/main.hpp"
+
+#include "arch/exception_handling/assert.hpp"
+#include "arch/memory/allocator/area_frame_allocator.hpp"
+#include "arch/memory/cpu/control_register.hpp"
+#include "arch/memory/cpu/msr.hpp"
+#include "arch/memory/heap/allocator.hpp"
+#include "arch/memory/paging/active_page_table.hpp"
+#include "arch/memory/paging/kernel_mapper.hpp"
+
+namespace teachos::arch::memory
+{
+  namespace
+  {
+    auto remap_heap(allocator::area_frame_allocator allocator, paging::active_page_table & active_table) -> void
+    {
+      auto heap_start_page = paging::virtual_page::containing_address(memory::heap::HEAP_START);
+      auto heap_end_page =
+          paging::virtual_page::containing_address(memory::heap::HEAP_START + memory::heap::HEAP_SIZE - 1);
+
+      for (auto i = heap_start_page.page_number; i <= heap_end_page.page_number; i++)
+      {
+        active_table.map_page_to_next_free_frame(allocator, paging::virtual_page{i}, paging::entry::WRITABLE);
+      }
+    }
+  }  // namespace
+
+  auto initialize_memory_management() -> void
+  {
+    static bool has_been_called = false;
+    arch::exception_handling::assert(!has_been_called,
+                                     "[Initialization] Memory management has already been initialized");
+    has_been_called = true;
+
+    auto const memory_information = multiboot::read_multiboot2();
+    allocator::area_frame_allocator allocator(memory_information);
+
+    cpu::set_cr2_bit(memory::cpu::cr2_flags::WRITE_PROTECT);
+    cpu::set_efer_bit(memory::cpu::efer_flags::NXE);
+
+    paging::kernel_mapper kernel(allocator, memory_information);
+    auto & active_table = kernel.remap_kernel();
+    video::vga::text::write("Kernel remapping successfull", video::vga::text::common_attributes::green_on_black);
+
+    remap_heap(allocator, active_table);
+  }
+}  // namespace teachos::arch::memory
\ No newline at end of file
-- 
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