Extract next_table_or_create into page_table

3 files changed, 33 insertions, 20 deletions

diff --git a/arch/x86_64/include/arch/memory/paging/page_mapper.hpp b/arch/x86_64/include/arch/memory/paging/page_mapper.hpp
index 80f6eb4..3590dda 100644
--- a/arch/x86_64/include/arch/memory/paging/page_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_mapper.hpp
@@ -65,24 +65,7 @@ namespace teachos::arch::memory::paging
 
     for (auto level = page_table_handle::LEVEL4; level != page_table_handle::LEVEL1; --level)
     {
-      auto level_index = page.get_level_index(level);
-      auto next_handle = current_handle.next_table(level_index);
-      // If the next table method failed then it means that the page level of the frame we want allocate has not yet
-      // been created itself. So we have to do that before we are able to allocate the wanted frame. This has to be done
-      // for every level, meaning we potenitally create a level 4, level 3 and level 2 page entry, each pointing to a
-      // page table one level below.
-      if (!next_handle)
-      {
-        auto allocated_frame = allocator.allocate_frame();
-        exception_handling::assert(allocated_frame.has_value(), "[Page mapper] Unable to allocate frame");
-        current_handle[level_index].set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE);
-        // There should now be an entry at the previously not existent index, therefore we can simply access it again.
-        next_handle = current_handle.next_table(level_index);
-        exception_handling::assert(next_handle.has_value(), "[Page mapper] Unable to create new entry into page table");
-        // TODO: Crashes when trying to access underlying entries array.
-        next_handle.value().zero_entries();
-      }
-      current_handle = next_handle.value();
+      current_handle = current_handle.next_table_or_create(allocator, page.get_level_index(level));
     }
 
     auto level1_entry = current_handle[page.get_level_index(page_table_handle::LEVEL1)];
diff --git a/arch/x86_64/include/arch/memory/paging/page_table.hpp b/arch/x86_64/include/arch/memory/paging/page_table.hpp
index eb0b984..8250e30 100644
--- a/arch/x86_64/include/arch/memory/paging/page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_table.hpp
@@ -1,6 +1,8 @@
 #ifndef TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_TABLE_HPP
 #define TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_TABLE_HPP
 
+#include "arch/exception_handling/assert.hpp"
+#include "arch/memory/allocator/area_frame_allocator.hpp"
 #include "arch/memory/paging/page_entry.hpp"
 
 namespace teachos::arch::memory::paging
@@ -61,6 +63,36 @@ namespace teachos::arch::memory::paging
     auto next_table(std::size_t table_index) -> std::optional<page_table_handle>;
 
     /**
+     * @brief Call next_table and then checks if the table already exists, if it does not it will use the given
+     * allocator to get the next free frame and set the entry to that instead.
+     *
+     * @param allocator Reference to an allocator following the FrameAllocator concept, which is used to allocate
+     * entries when a new page table is required.
+     * @param table_index Index of this page table in the page table one level lower.
+     */
+    template<allocator::FrameAllocator T>
+    auto next_table_or_create(T & allocator, std::size_t table_index) -> page_table_handle
+    {
+      auto next_handle = next_table(table_index);
+      // If the next table method failed then it means that the page level of the frame we want allocate has not yet
+      // been created itself. So we have to do that before we are able to allocate the wanted frame. This has to be done
+      // for every level, meaning we potenitally create a level 4, level 3 and level 2 page entry, each pointing to a
+      // page table one level below.
+      if (!next_handle)
+      {
+        auto allocated_frame = allocator.allocate_frame();
+        exception_handling::assert(allocated_frame.has_value(), "[Page mapper] Unable to allocate frame");
+        this->operator[](table_index).set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE);
+        // There should now be an entry at the previously not existent index, therefore we can simply access it again.
+        next_handle = next_table(table_index);
+        exception_handling::assert(next_handle.has_value(), "[Page mapper] Unable to create new entry into page table");
+        // TODO: Crashes when trying to access underlying entries array.
+        next_handle.value().zero_entries();
+      }
+      return next_handle.value();
+    }
+
+    /**
      * @brief Index operator overload to access specific immutable entry directy.
      *
      * @param index Index of the entry we want to access and only read.
diff --git a/arch/x86_64/src/memory/paging/page_table.cpp b/arch/x86_64/src/memory/paging/page_table.cpp
index 33d0b75..40662e3 100644
--- a/arch/x86_64/src/memory/paging/page_table.cpp
+++ b/arch/x86_64/src/memory/paging/page_table.cpp
@@ -1,7 +1,5 @@
 #include "arch/memory/paging/page_table.hpp"
 
-#include "arch/exception_handling/assert.hpp"
-
 namespace teachos::arch::memory::paging
 {
   /**