Identity map memory map and vga text buffer,w hen setting up kernel

3 files changed, 23 insertions, 4 deletions

diff --git a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
index c91c5f0..d1b9325 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -5,6 +5,7 @@
 #include "arch/memory/paging/active_page_table.hpp"
 #include "arch/memory/paging/inactive_page_table.hpp"
 #include "arch/memory/paging/temporary_page.hpp"
+#include "arch/video/vga/text.hpp"
 
 namespace teachos::arch::memory::paging
 {
@@ -124,19 +125,35 @@ namespace teachos::arch::memory::paging
         // End address is exclusive, so that it is not part of the section anymore (one past the last frame of this
         // section). But end frame would now point to the actual last frame and not one past the last frame, therefore
         // we increment by one to get one past the last frame of this section.
-        auto end_frame =
+        auto const end_frame =
             ++(allocator::physical_frame::containing_address(section.physical_address + section.section_size - 1));
 
         allocator::frame_container::iterator const begin{start_frame};
         allocator::frame_container::iterator const end{end_frame};
-        allocator::frame_container frames{begin, end};
-        entry entry{section.flags};
+        allocator::frame_container const frames{begin, end};
+        entry const entry{section.flags};
 
         for (auto const & frame : frames)
         {
           active_table.identity_map(allocator, frame, entry.get_flags());
         }
       }
+
+      auto const vga_buffer_frame =
+          allocator::physical_frame::containing_address(video::vga::text::DEFAULT_VGA_TEXT_BUFFER_ADDRESS);
+      active_table.identity_map(allocator, vga_buffer_frame, entry::WRITABLE);
+
+      auto const multiboot_start_frame = allocator::physical_frame::containing_address(mem_info.multiboot_start);
+      auto const multiboot_end_frame = ++allocator::physical_frame::containing_address(mem_info.multiboot_end - 1);
+
+      allocator::frame_container::iterator const multiboot_begin{multiboot_start_frame};
+      allocator::frame_container::iterator const multiboot_end{multiboot_end_frame};
+      allocator::frame_container const multiboot_frames{multiboot_begin, multiboot_end};
+
+      for (auto const & frame : multiboot_frames)
+      {
+        active_table.identity_map(allocator, frame, entry::PRESENT);
+      }
     }
 
     T & allocator;
diff --git a/arch/x86_64/include/arch/memory/paging/page_entry.hpp b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
index ab9659d..a7ba262 100644
--- a/arch/x86_64/include/arch/memory/paging/page_entry.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
@@ -104,7 +104,7 @@ namespace teachos::arch::memory::paging
      *
      * @return Extracted entry flags, without the physical address.
      */
-    auto get_flags() -> std::bitset<64U>;
+    auto get_flags() const -> std::bitset<64U>;
 
   private:
     std::bitset<64U> flags;  ///< Underlying bitset used to read the flags from. Bits 9 - 11 and 52 - 62 can be
diff --git a/arch/x86_64/include/arch/video/vga/text.hpp b/arch/x86_64/include/arch/video/vga/text.hpp
index f200da4..665dc1c 100644
--- a/arch/x86_64/include/arch/video/vga/text.hpp
+++ b/arch/x86_64/include/arch/video/vga/text.hpp
@@ -7,6 +7,8 @@
 
 namespace teachos::arch::video::vga::text
 {
+  auto constexpr DEFAULT_VGA_TEXT_BUFFER_ADDRESS = 0xB8000;
+
   /**
    * @brief The colors available in the standard VGA text mode.
    */