Add translate huge page method

1 files changed, 40 insertions, 4 deletions

diff --git a/arch/x86_64/src/memory/paging/page_mapper.cpp b/arch/x86_64/src/memory/paging/page_mapper.cpp
index 5372561..e68bc68 100644
--- a/arch/x86_64/src/memory/paging/page_mapper.cpp
+++ b/arch/x86_64/src/memory/paging/page_mapper.cpp
@@ -8,7 +8,8 @@ namespace teachos::arch::memory::paging
   {
     page_table page_table{};
     bool is_valid = false;
-    auto huge_page = []() -> std::optional<allocator::physical_frame> { return std::nullopt; };
+
+    auto huge_page = [&]() -> std::optional<allocator::physical_frame> {};
 
     for (auto level = page_table::LEVEL4; level != page_table::LEVEL1; level--)
     {
@@ -22,11 +23,46 @@ namespace teachos::arch::memory::paging
     if (is_valid)
     {
       auto level1_index = page.get_level_index(page_table::LEVEL1);
-      auto frame = page_table[level1_index].calculate_pointed_to_frame();
-      return frame;
+      auto level1_frame = page_table[level1_index].calculate_pointed_to_frame();
+      return level1_frame;
     }
 
-    return huge_page();
+    return translate_huge_page(page);
+  }
+
+  auto translate_huge_page(virtual_page page) -> std::optional<allocator::physical_frame>
+  {
+    page_table page_table{};
+    bool is_valid = page_table.next_table(page.get_level_index(page_table::LEVEL3));
+
+    if (is_valid)
+    {
+      auto level3_entry = page_table[page.get_level_index(page_table::LEVEL3)];
+      auto level3_optional_frame = level3_entry.calculate_pointed_to_frame();
+      if (level3_optional_frame.has_value() && level3_entry.contains_flags(entry::HUGE_PAGE))
+      {
+        auto level3_frame = level3_optional_frame.value();
+        exception_handling::assert(level3_frame.frame_number % (PAGE_TABLE_ENTRY_COUNT * PAGE_TABLE_ENTRY_COUNT) == 0U,
+                                   "[Page Mapper] Physical address must be 1 GiB aligned");
+        return allocator::physical_frame{level3_frame.frame_number +
+                                         page.get_level_index(page_table::LEVEL2) * PAGE_TABLE_ENTRY_COUNT +
+                                         page.get_level_index(page_table::LEVEL1)};
+      }
+    }
+    is_valid = page_table.next_table(page.get_level_index(page_table::LEVEL3));
+    if (is_valid)
+    {
+      auto level2_entry = page_table[page.get_level_index(page_table::LEVEL2)];
+      auto level2_optional_frame = level2_entry.calculate_pointed_to_frame();
+      if (level2_optional_frame.has_value() && level2_entry.contains_flags(entry::HUGE_PAGE))
+      {
+        auto level2_frame = level2_optional_frame.value();
+        exception_handling::assert(level2_frame.frame_number % PAGE_TABLE_ENTRY_COUNT == 0U,
+                                   "[Page Mapper] Physical address must be 2 MiB aligned");
+        return allocator::physical_frame{level2_frame.frame_number + page.get_level_index(page_table::LEVEL1)};
+      }
+    }
+    return std::nullopt;
   }
 
   auto translate_address(std::size_t virtual_address) -> std::optional<std::size_t>