From ef156dd6430855434b54275b22cd43ee3cedcfdc Mon Sep 17 00:00:00 2001
From: Fabian Imhof <fabian.imhof@ost.ch>
Date: Sun, 11 May 2025 09:29:56 +0000
Subject: make frame_allocator and active_page_table statically available

---
 arch/x86_64/src/memory/main.cpp | 59 +++++++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 23 deletions(-)

(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
index 4cdfa80..595cb0d 100644
--- a/arch/x86_64/src/memory/main.cpp
+++ b/arch/x86_64/src/memory/main.cpp
@@ -9,37 +9,47 @@
 #include "arch/memory/paging/active_page_table.hpp"
 #include "arch/memory/paging/kernel_mapper.hpp"
 
+#include <optional>
+
 namespace teachos::arch::memory
 {
   namespace
   {
-    template<allocator::FrameAllocator T>
-    auto create_frame_allocator(multiboot::memory_information const & memory_information) -> T
+    static std::optional<allocator::area_frame_allocator> frame_allocator;
+
+    auto create_frame_allocator(multiboot::memory_information const & memory_information)
+        -> allocator::area_frame_allocator
     {
-      return allocator::area_frame_allocator{memory_information};
+      frame_allocator.emplace(memory_information);
+      return frame_allocator.value();
     }
 
-    template<allocator::FrameAllocator T>
-    auto remap_heap(T & allocator, paging::active_page_table & active_table, bool is_user_heap = false) -> void
+    auto get_frame_allocator() -> allocator::area_frame_allocator
     {
-      auto const heap_start = is_user_heap ? heap::USER_HEAP_START : heap::KERNEL_HEAP_START;
-      auto const heap_size = is_user_heap ? heap::USER_HEAP_SIZE : heap::KERNEL_HEAP_SIZE;
+      exception_handling::assert(frame_allocator.has_value(), "[Memory main] Frame allocator has not been created yet");
+      return frame_allocator.value();
+    }
+  }  // namespace
+
+  auto remap_heap(std::size_t heap_start, std::size_t heap_size, paging::entry::bitset additional_flags = {}) -> void
+  {
+    auto allocator = get_frame_allocator();
+    decltype(auto) active_table = paging::active_page_table::create_or_get();
+    auto const start_page = paging::virtual_page::containing_address(heap_start);
+    auto const end_page = ++(paging::virtual_page::containing_address(heap_start + heap_size - 1));
 
-      auto const start_page = paging::virtual_page::containing_address(heap_start);
-      auto const end_page = ++(paging::virtual_page::containing_address(heap_start + heap_size - 1));
-      paging::page_container::iterator const begin{start_page};
-      paging::page_container::iterator const end{end_page};
-      paging::page_container const pages{begin, end};
+    paging::page_container::iterator const begin{start_page};
+    paging::page_container::iterator const end{end_page};
+    paging::page_container const pages{begin, end};
 
-      constexpr auto base_flags = paging::entry::WRITABLE;
-      auto const flags = is_user_heap ? base_flags | paging::entry::USER_ACCESSIBLE : base_flags;
+    constexpr auto base_flags = paging::entry::WRITABLE;
+    auto const flags = base_flags | additional_flags;
 
-      for (auto const & page : pages)
-      {
-        active_table.map_page_to_next_free_frame(allocator, page, flags);
-      }
+    for (auto const & page : pages)
+    {
+      active_table.map_page_to_next_free_frame(allocator, page, flags);
     }
-  }  // namespace
+  }
 
   auto initialize_memory_management() -> void
   {
@@ -49,18 +59,21 @@ namespace teachos::arch::memory
     has_been_called = true;
 
     auto const memory_information = multiboot::read_multiboot2();
-    auto allocator = create_frame_allocator<allocator::area_frame_allocator>(memory_information);
+    auto allocator = create_frame_allocator(memory_information);
 
     kernel::cpu::set_cr0_bit(kernel::cpu::cr0_flags::WRITE_PROTECT);
     kernel::cpu::set_efer_bit(kernel::cpu::efer_flags::NXE);
 
     paging::kernel_mapper kernel(allocator, memory_information);
-    auto & active_table = kernel.remap_kernel();
+    kernel.remap_kernel();
     video::vga::text::write("Kernel remapping successful", video::vga::text::common_attributes::green_on_black);
     video::vga::text::newline();
 
-    remap_heap(allocator, active_table);        // Remap kernel heap
-    remap_heap(allocator, active_table, true);  // Remap user heap
+    // Remap kernel heap
+    remap_heap(heap::KERNEL_HEAP_START, heap::KERNEL_HEAP_SIZE);
+    // Remap user heap
+    remap_heap(heap::USER_HEAP_SIZE, heap::USER_HEAP_SIZE, paging::entry::USER_ACCESSIBLE);
+
     video::vga::text::write("Heap remapping successful", video::vga::text::common_attributes::green_on_black);
     video::vga::text::newline();
   }
-- 
cgit v1.2.3