Fix linker error using friend method 👬

3 files changed, 41 insertions, 16 deletions

diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 8e5aa05..3e25d2d 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -10,6 +10,7 @@
 
 namespace teachos::arch::kernel
 {
+
   auto main() -> void
   {
     video::vga::text::clear();
@@ -19,6 +20,25 @@ namespace teachos::arch::kernel
     auto memory_information = memory::multiboot::read_multiboot2();
     memory::allocator::area_frame_allocator allocator(memory_information);
 
+    size_t address = 42 * memory::paging::PAGE_TABLE_ENTRY_COUNT * memory::paging::PAGE_TABLE_ENTRY_COUNT *
+                     memory::allocator::PAGE_FRAME_SIZE;  // 42th P3 entry
+    auto page = memory::paging::virtual_page::containing_address(address);
+    auto frame = allocator.allocate_frame();
+    exception_handling::assert(frame.has_value(), "[Main] Out of memory exception");
+    auto optional_frame = memory::paging::translate_page(page);
+    memory::paging::map_page_to_frame(allocator, page, frame.value(), 0U);
+    optional_frame = memory::paging::translate_page(page);
+    video::vga::text::newline();
+    video::vga::text::write("Mapped physical frame: ", video::vga::text::common_attributes::green_on_black);
+    video::vga::text::write_number(optional_frame.value().frame_number,
+                                   video::vga::text::common_attributes::green_on_black);
+
+    memory::paging::unmap_page(allocator, page);
+    video::vga::text::write("Unapped physical page: ", video::vga::text::common_attributes::green_on_black);
+    optional_frame = memory::paging::translate_page(page);
+    exception_handling::assert(!optional_frame.has_value(), "[Main] Ummapping failed");
+    video::vga::text::write_number(page.page_number, video::vga::text::common_attributes::green_on_black);
+
     auto last_allocated = allocator.allocate_frame();
     auto allocated = last_allocated;
     do
@@ -26,12 +46,9 @@ namespace teachos::arch::kernel
       last_allocated = allocated;
       allocated = allocator.allocate_frame();
     } while (allocated);
-    video::vga::text::write("Allocated Frames", video::vga::text::common_attributes::green_on_black);
+    video::vga::text::newline();
+    video::vga::text::write("Allocated Frames: ", video::vga::text::common_attributes::green_on_black);
     video::vga::text::write_number(last_allocated.value().frame_number,
                                    video::vga::text::common_attributes::green_on_black);
-    memory::paging::map_page_to_frame(allocator, memory::paging::virtual_page{0U}, last_allocated.value(), 0U);
-    memory::paging::map_next_free_page_to_frame(allocator, memory::paging::virtual_page{0U}, 0U);
-    memory::paging::identity_map(allocator, last_allocated.value(), 0U);
-    memory::paging::unmap_page(allocator, memory::paging::virtual_page{0U});
   }
 }  // namespace teachos::arch::kernel
diff --git a/arch/x86_64/src/memory/paging/page_mapper.cpp b/arch/x86_64/src/memory/paging/page_mapper.cpp
index b8f6b89..75b17ff 100644
--- a/arch/x86_64/src/memory/paging/page_mapper.cpp
+++ b/arch/x86_64/src/memory/paging/page_mapper.cpp
@@ -14,15 +14,23 @@ namespace teachos::arch::memory::paging
     return page_table_handle{active_page, page_table_handle::LEVEL4};
   }
 
+  auto subtract_level(page_table_handle::level level) -> page_table_handle::level
+  {
+    exception_handling::assert(level != page_table_handle::LEVEL1,
+                               "[Page table] Attemptd to decrement enum to value outside of range");
+    auto value = static_cast<std::underlying_type<page_table_handle::level>::type>(level);
+    return static_cast<page_table_handle::level>(--value);
+  }
+
   auto translate_page(virtual_page page) -> std::optional<allocator::physical_frame>
   {
     auto current_handle = create_or_get();
 
-    for (auto level = page_table_handle::LEVEL4; level != page_table_handle::LEVEL1; level--)
+    for (auto level = page_table_handle::LEVEL4; level != page_table_handle::LEVEL1; level = subtract_level(level))
     {
       auto next_handle = current_handle.next_table(page.get_level_index(level));
-      // If the next table method failed then it is highly likely that it was a huge page and we therefore have to parse
-      // the table differently. Therefore, we attempt to parse it using the method required by huge pages.
+      // If the next table method failed then it is highly likely that it was a huge page and we therefore have to
+      // parse the table differently. Therefore, we attempt to parse it using the method required by huge pages.
       if (!next_handle)
       {
         return translate_huge_page(page);
diff --git a/arch/x86_64/src/memory/paging/page_table.cpp b/arch/x86_64/src/memory/paging/page_table.cpp
index 852bbd5..9c9ca76 100644
--- a/arch/x86_64/src/memory/paging/page_table.cpp
+++ b/arch/x86_64/src/memory/paging/page_table.cpp
@@ -47,14 +47,6 @@ namespace teachos::arch::memory::paging
                                             ///< virtual addresses for the level 1 page table.
   };
 
-  auto operator--(page_table_handle::level level, int) -> page_table_handle::level
-  {
-    exception_handling::assert(level != page_table_handle::LEVEL1,
-                               "[Page table] Attemptd to decrement enum to value outside of range");
-    auto value = static_cast<std::underlying_type<page_table_handle::level>::type>(level);
-    return static_cast<page_table_handle::level>(--value);
-  }
-
   auto page_table::zero_entries() -> void
   {
     constexpr size_t entry_amount = sizeof(entries) / sizeof(entries[0]);
@@ -117,4 +109,12 @@ namespace teachos::arch::memory::paging
   }
 
   auto page_table_handle::operator[](std::size_t index) const -> entry { return handle->operator[](index); }
+
+  auto operator--(page_table_handle::level value, int) -> page_table_handle::level
+  {
+    exception_handling::assert(value != page_table_handle::LEVEL1,
+                               "[Page table] Attemptd to decrement enum to value outside of range");
+    auto new_value = static_cast<std::underlying_type<page_table_handle::level>::type>(value);
+    return static_cast<page_table_handle::level>(--new_value);
+  }
 }  // namespace teachos::arch::memory::paging