Improve calculation of kernel end and start address.

3 files changed, 12 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 10fad0c..f01bd37 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -38,7 +38,7 @@ namespace teachos::arch::memory::paging
      * inactive page table, that is not used by the CPU to ensure we are not changign memory that we are using. Because
      * remapping active kernel memory in the kernel wouldn't work.
      */
-    auto remap_kernel() -> void
+    auto remap_kernel() -> active_page_table &
     {
       temporary_page temporary_page{virtual_page{0xCAFEBABE}, allocator};
       auto & active_table = active_page_table::create_or_get();
@@ -51,6 +51,7 @@ namespace teachos::arch::memory::paging
       auto const old_level_4_page =
           virtual_page::containing_address(old_table.page_table_level_4_frame.start_address());
       active_table.unmap_page(allocator, old_level_4_page);
+      return active_table;
     }
 
   private:
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index ea1a157..f9b252d 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -25,9 +25,11 @@ namespace teachos::arch::kernel
     memory::cpu::set_efer_bit(memory::cpu::efer_flags::NXE);
 
     memory::paging::kernel_mapper kernel(allocator, memory_information);
-    kernel.remap_kernel();
+    auto & active_table = kernel.remap_kernel();
     video::vga::text::write("Kernel remapping successfull", video::vga::text::common_attributes::green_on_black);
 
+    // TODO: Map heap virtual pages with active table
+
     /*
         size_t address = 42 * memory::paging::PAGE_TABLE_ENTRY_COUNT * memory::paging::PAGE_TABLE_ENTRY_COUNT *
                          memory::allocator::PAGE_FRAME_SIZE;  // 42th P3 entry
diff --git a/arch/x86_64/src/memory/multiboot/reader.cpp b/arch/x86_64/src/memory/multiboot/reader.cpp
index 1dd18ff..2bf5b25 100644
--- a/arch/x86_64/src/memory/multiboot/reader.cpp
+++ b/arch/x86_64/src/memory/multiboot/reader.cpp
@@ -6,6 +6,7 @@
 #include "arch/memory/multiboot/info.hpp"
 
 #include <algorithm>
+#include <ranges>
 
 namespace teachos::arch::memory::multiboot
 {
@@ -56,11 +57,15 @@ namespace teachos::arch::memory::multiboot
 
       elf_section_header_container sections{begin, end};
 
+      auto allocated_sections = sections | std::views::filter([](auto const & section) {
+                                  return section.flags.contains_flags(elf_section_flags::OCCUPIES_MEMORY);
+                                });
+
       auto const elf_section_with_lowest_physical_address = std::ranges::min_element(
-          sections, [](auto const & a, auto const & b) { return a.physical_address < b.physical_address; });
+          allocated_sections, [](auto const & a, auto const & b) { return a.physical_address < b.physical_address; });
 
       auto const elf_section_with_highest_physical_address =
-          std::ranges::max_element(sections, [](auto const & a, auto const & b) {
+          std::ranges::max_element(allocated_sections, [](auto const & a, auto const & b) {
             auto a_physical_address_end = a.physical_address + a.section_size;
             auto b_physical_address_end = b.physical_address + b.section_size;
             return a_physical_address_end < b_physical_address_end;