Move compelte multiboot2 code into seperate files and behaviour into seperate static class

1 files changed, 3 insertions, 148 deletions

diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index babe251..c0d4aed 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -1,120 +1,14 @@
 #include "arch/kernel/main.hpp"
 
-#include "arch/boot/pointers.hpp"
 #include "arch/exception_handling/assert.hpp"
 #include "arch/memory/frame_allocator.hpp"
-#include "arch/memory/multiboot.hpp"
+#include "arch/memory/multiboot/reader.hpp"
 #include "arch/video/vga/text.hpp"
 
 #include <algorithm>
 
 namespace teachos::arch::kernel
 {
-  auto process_memory_map(arch::memory::memory_map * mminfo, arch::memory::memory_area *& memory_areas,
-                          uint8_t & area_count) -> void
-  {
-    auto expected_entry_size = mminfo->entry_size;
-    constexpr auto actual_entry_size = sizeof(arch::memory::memory_area);
-    arch::exception_handling::assert(expected_entry_size == actual_entry_size, "Unexpected memoryarea entry size");
-
-    auto total_size = mminfo->tag.size;
-    auto total_entries_size = total_size - sizeof(arch::memory::memory_map) + actual_entry_size;
-    auto number_of_entries = total_entries_size / actual_entry_size;
-
-    memory_areas = &mminfo->entries;
-    area_count = number_of_entries;
-  }
-
-  auto process_elf_sections(arch::memory::elf_symbols_section * symbol, uint64_t & kernel_start,
-                            uint64_t & kernel_end) -> void
-  {
-    auto expected_entry_size = symbol->entry_size;
-    constexpr auto actual_entry_size = sizeof(arch::memory::elf_section_header);
-    arch::exception_handling::assert(expected_entry_size == actual_entry_size,
-                                     "Unexpected elf_section_header entry size");
-
-    auto expected_total_size = symbol->tag.size;
-    auto actual_total_entry_size = actual_entry_size * symbol->number_of_sections;
-    constexpr auto actual_total_section_size = sizeof(arch::memory::elf_symbols_section) - sizeof(uint32_t);
-    auto actual_total_size = actual_total_entry_size + actual_total_section_size;
-    arch::exception_handling::assert(expected_total_size == actual_total_size, "Unexpected elf_symbols total size");
-
-    auto begin = reinterpret_cast<arch::memory::elf_section_header *>(&symbol->end);
-    auto end = begin + symbol->number_of_sections;
-    arch::exception_handling::assert(begin->is_null(), "Missing elf_section_header begin");
-
-    std::size_t symbol_table_section_count = 0U;
-    std::size_t dynamic_section_count = 0U;
-
-    for (auto section = begin; section != end; ++section)
-    {
-      bool const writable = section->flags.contains_flags(arch::memory::elf_section_flags::WRITABLE);
-      bool const occupies_memory = section->flags.contains_flags(arch::memory::elf_section_flags::OCCUPIES_MEMORY);
-      bool const is_executable = section->flags.contains_flags(arch::memory::elf_section_flags::EXECUTABLE_CODE);
-      bool const contains_duplicate_data =
-          section->flags.contains_flags(arch::memory::elf_section_flags::DUPLICATE_DATA);
-      bool const contains_strings = section->flags.contains_flags(arch::memory::elf_section_flags::CONTAINS_STRING);
-      bool const section_header_info_is_section_header_table_index = section->flags.contains_flags(
-          arch::memory::elf_section_flags::SECTION_HEADER_INFO_IS_SECTION_HEADER_TABLE_INDEX);
-      bool const preserve_ordering_after_combination =
-          section->flags.contains_flags(arch::memory::elf_section_flags::PRESERVE_ORDERING_AFTER_COMBINATION);
-      bool const requires_special_os_processing =
-          section->flags.contains_flags(arch::memory::elf_section_flags::REQUIRES_SPECIAL_OS_PROCESSING);
-      bool const is_section_group_member =
-          section->flags.contains_flags(arch::memory::elf_section_flags::SECTION_GROUP_MEMBER);
-      bool const holds_thread_local_data =
-          section->flags.contains_flags(arch::memory::elf_section_flags::HOLDS_THREAD_LOCAL_DATA);
-      bool const is_compressed = section->flags.contains_flags(arch::memory::elf_section_flags::COMPRESSED);
-      bool const has_special_ordering_requirements =
-          section->flags.contains_flags(arch::memory::elf_section_flags::SPECIAL_ORDERING_REQUIREMENTS);
-      bool const is_excluded_unless_referenced_or_allocated =
-          section->flags.contains_flags(arch::memory::elf_section_flags::EXCLUDED_UNLESS_REFERENCED_OR_ALLOCATED);
-
-      if (writable && occupies_memory && is_executable && contains_duplicate_data && contains_strings &&
-          section_header_info_is_section_header_table_index && preserve_ordering_after_combination &&
-          requires_special_os_processing && is_section_group_member && holds_thread_local_data && is_compressed &&
-          has_special_ordering_requirements && is_excluded_unless_referenced_or_allocated)
-      {
-      }
-
-      switch (section->type)
-      {
-        case arch::memory::elf_section_type::PROGRAMM: {
-          if (section->virtual_address < kernel_start)
-          {
-            kernel_start = section->virtual_address;
-          }
-          auto virtual_address_end = section->virtual_address + section->section_size;
-          if (virtual_address_end > kernel_end)
-          {
-            kernel_end = virtual_address_end;
-          }
-          break;
-        }
-        case arch::memory::elf_section_type::DYNAMIC_SYMBOL_TABLE:
-        case arch::memory::elf_section_type::SYMBOL_TABLE:
-          symbol_table_section_count++;
-          break;
-        case arch::memory::elf_section_type::DYNAMIC:
-          dynamic_section_count++;
-          break;
-        default:
-          // All other cases are not important and can be ignored
-          break;
-      }
-    }
-
-    arch::exception_handling::assert(symbol_table_section_count == 1U, "Unexpected symbol_table_count value");
-    arch::exception_handling::assert(dynamic_section_count <= 1U, "Unexpected dynamic_section_count value");
-  }
-
-  template<typename T>
-    requires std::is_pointer<T>::value
-  auto align_to_8_byte_boundary(T ptr, uint32_t size) -> T
-  {
-    return reinterpret_cast<T>(reinterpret_cast<uint8_t *>(ptr) + ((size + 7) & ~7));
-  }
-
   auto main() -> void
   {
     using namespace video::vga;
@@ -123,47 +17,8 @@ namespace teachos::arch::kernel
     text::cursor(false);
     text::write("TeachOS is starting up...", text::common_attributes::green_on_black);
 
-    auto * multiboot_information_pointer =
-        reinterpret_cast<arch::memory::multi_boot_info *>(arch::boot::multiboot_information_pointer);
-    auto multiboot_tag = &(multiboot_information_pointer->tags);
-
-    uint64_t kernel_start = UINT64_MAX;
-    uint64_t kernel_end = 0;
-    uint64_t multiboot_start = arch::boot::multiboot_information_pointer;
-    uint64_t multiboot_end = multiboot_start + multiboot_information_pointer->total_size;
-    arch::memory::memory_area * memory_areas = nullptr;
-    uint8_t area_count = 0;
-
-    /*
-     * Loop over the multiboot2 tags to access the information needed.
-     * Tags are defined in the header file and are padded so that each
-     * Tag starts at an 8-bytes aligned adress.
-     *
-     * The increment part aligns the size to an 8-byte address.
-     */
-    for (auto tag = multiboot_tag; tag->type != arch::memory::multi_boot_tag_type::END;
-         tag = align_to_8_byte_boundary(tag, tag->size))
-    {
-      switch (tag->type)
-      {
-        case arch::memory::multi_boot_tag_type::ELF_SECTIONS: {
-          auto symbol = reinterpret_cast<teachos::arch::memory::elf_symbols_section *>(tag);
-          process_elf_sections(symbol, kernel_start, kernel_end);
-          break;
-        }
-        case arch::memory::multi_boot_tag_type::MEMORY_MAP: {
-          auto mminfo = reinterpret_cast<teachos::arch::memory::memory_map *>(tag);
-          process_memory_map(mminfo, memory_areas, area_count);
-          break;
-        }
-        default:
-          // All other cases are not important and can be ignored
-          break;
-      }
-    }
-
-    auto allocator = arch::memory::area_frame_allocator(kernel_start, kernel_end, multiboot_start, multiboot_end,
-                                                        memory_areas, area_count);
+    auto memory_information = memory::multiboot::read_multiboot2();
+    auto allocator = memory::area_frame_allocator(memory_information);
 
     auto last_allocated = allocator.allocate_frame();
     auto allocated = last_allocated;