From f8928c877c48b5beba9bb42876f70213aba68f88 Mon Sep 17 00:00:00 2001
From: Fabian Imhof <fabian.imhof@ost.ch>
Date: Sun, 20 Oct 2024 07:46:51 +0000
Subject: translate

---
 .../include/arch/memory/paging/virtual_page.hpp    | 63 +++++++++++++++++++++-
 arch/x86_64/src/memory/multiboot/reader.cpp        |  1 +
 arch/x86_64/src/memory/paging/page_table.cpp       |  2 +-
 arch/x86_64/src/memory/paging/virtual_page.cpp     |  1 -
 4 files changed, 64 insertions(+), 3 deletions(-)

(limited to 'arch')

diff --git a/arch/x86_64/include/arch/memory/paging/virtual_page.hpp b/arch/x86_64/include/arch/memory/paging/virtual_page.hpp
index a2e5316..b2adca3 100644
--- a/arch/x86_64/include/arch/memory/paging/virtual_page.hpp
+++ b/arch/x86_64/include/arch/memory/paging/virtual_page.hpp
@@ -1,12 +1,73 @@
 #ifndef TEACHOS_ARCH_X86_64_MEMORY_PAGING_VIRTUAL_PAGE_HPP
 #define TEACHOS_ARCH_X86_64_MEMORY_PAGING_VIRTUAL_PAGE_HPP
 
-#include "page_table.hpp"
+#include "arch/memory/allocator/physical_frame.hpp"
+#include "arch/memory/paging/page_table.hpp"
+
 #include <compare>
 #include <cstdint>
+#include <optional>
 
 namespace teachos::arch::memory::paging
 {
+  /**
+   * @brief Translate virtual into phyical address
+   *
+   * @param virtual_address Address to translate into physical
+   * @return Physical address
+   */
+  auto static translate_address(std::size_t virtual_address) -> std::optional<std::size_t>
+  {
+    std::size_t offset = virtual_address % allocator::PAGE_FRAME_SIZE;
+    virtual_page page = virtual_page::containing_address(virtual_address);
+    allocator::physical_frame frame = paging::translate_page(page);
+
+    if (frame.value())
+    {
+      return frame->number * allocator::PAGE_FRAME_SIZE + offset;
+    }
+
+    return std::nullopt;
+  }
+
+  /**
+   * @brief Translate page into physical_frame
+   *
+   * @param page Page to translate into physical_frame
+   * @return Physical frame corresponding to the provided page_table
+   */
+  auto static translate_page(virtual_page page) -> std::optional<allocator::physical_frame>
+  {
+    auto level3 =
+        reinterpret_cast<page_table>(page_table::LEVEL4)->next_table(page.get_level_index(page_table::LEVEL4));
+
+    auto huge_page = []() {
+      // TODO
+    };
+
+    if (level3.value())
+    {
+      auto level2 = level3->next_table(page.get_level_index(page_table::LEVEL3));
+
+      if (level2.value())
+      {
+        auto level1 = level2->next_table(page.get_level_index(page_table::LEVEL2));
+
+        if (level1.value())
+        {
+          auto frame = level1[page.get_level_index(page_table::LEVEL1)].calculate_pointed_to_frame();
+
+          if (frame.value())
+          {
+            return frame;
+          }
+        }
+      }
+    }
+
+    return huge_page();
+  }
+
   /**
    * @brief Virtual page entry contained in P1 page tables
    */
diff --git a/arch/x86_64/src/memory/multiboot/reader.cpp b/arch/x86_64/src/memory/multiboot/reader.cpp
index 156b437..565f604 100644
--- a/arch/x86_64/src/memory/multiboot/reader.cpp
+++ b/arch/x86_64/src/memory/multiboot/reader.cpp
@@ -111,6 +111,7 @@ namespace teachos::arch::memory::multiboot
           break;
       }
     }
+
     return mem_info;
   }
 }  // namespace teachos::arch::memory::multiboot
diff --git a/arch/x86_64/src/memory/paging/page_table.cpp b/arch/x86_64/src/memory/paging/page_table.cpp
index 9857294..3fb7a3f 100644
--- a/arch/x86_64/src/memory/paging/page_table.cpp
+++ b/arch/x86_64/src/memory/paging/page_table.cpp
@@ -45,7 +45,7 @@ namespace teachos::arch::memory::paging
     if (entry.contains_flags(entry::PRESENT) && !entry.contains_flags(entry::HUGE_PAGE))
     {
       std::size_t const table_address = reinterpret_cast<std::size_t>(current_table);
-      return (table_address << 9) | (table_index << 12);
+      return ((table_address << 9) | (table_index << 12));
     }
     // TODO: Implement behaviour for huge pages currently not done
     return std::nullopt;
diff --git a/arch/x86_64/src/memory/paging/virtual_page.cpp b/arch/x86_64/src/memory/paging/virtual_page.cpp
index dcdec7f..9b803d2 100644
--- a/arch/x86_64/src/memory/paging/virtual_page.cpp
+++ b/arch/x86_64/src/memory/paging/virtual_page.cpp
@@ -1,7 +1,6 @@
 #include "arch/memory/paging/virtual_page.hpp"
 
 #include "arch/exception_handling/assert.hpp"
-#include "arch/memory/allocator/physical_frame.hpp"
 
 namespace teachos::arch::memory::paging
 {
-- 
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