From e5206b3bf1883fd9601a37f5cce392d8080b8791 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= <matteo.gmuer1@ost.ch>
Date: Sun, 20 Oct 2024 07:43:00 +0000
Subject: Add get level index method to virtual page

---
 arch/x86_64/include/arch/memory/paging/page_entry.hpp   |  2 +-
 arch/x86_64/include/arch/memory/paging/page_table.hpp   | 10 +---------
 arch/x86_64/include/arch/memory/paging/virtual_page.hpp | 11 ++++++++++-
 arch/x86_64/src/memory/paging/page_table.cpp            |  8 ++------
 arch/x86_64/src/memory/paging/virtual_page.cpp          |  5 +++++
 5 files changed, 19 insertions(+), 17 deletions(-)

(limited to 'arch/x86_64')

diff --git a/arch/x86_64/include/arch/memory/paging/page_entry.hpp b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
index a40e764..016e054 100644
--- a/arch/x86_64/include/arch/memory/paging/page_entry.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
@@ -87,4 +87,4 @@ namespace teachos::arch::memory::paging
   };
 }  // namespace teachos::arch::memory::paging
 
-#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_ENTRY_HPP
\ No newline at end of file
+#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_ENTRY_HPP
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 73b75ad..bbee477 100644
--- a/arch/x86_64/include/arch/memory/paging/page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_table.hpp
@@ -73,14 +73,6 @@ namespace teachos::arch::memory::paging
     auto operator[](std::size_t index) const -> entry const &;
 
   private:
-    /**
-     * @brief Constructor. Used internally to create new page tables.
-     *
-     * @param new_level New level of the page table.
-     * @param new_table New table data contained in the page table.
-     */
-    page_table(level new_level, table_content * new_table);
-
     /**
      * @brief Calculates the address of the next page table level for the given table index. The next page table address
      * is only valid if the corresponding entry is present and not a huge page. Meaning we use an index into a
@@ -97,4 +89,4 @@ namespace teachos::arch::memory::paging
   };
 }  // namespace teachos::arch::memory::paging
 
-#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_TABLE_HPP
\ No newline at end of file
+#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_PAGE_TABLE_HPP
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 7871e4b..a2e5316 100644
--- a/arch/x86_64/include/arch/memory/paging/virtual_page.hpp
+++ b/arch/x86_64/include/arch/memory/paging/virtual_page.hpp
@@ -1,6 +1,7 @@
 #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 <compare>
 #include <cstdint>
 
@@ -33,6 +34,14 @@ namespace teachos::arch::memory::paging
      */
     auto start_address() const -> uint64_t;
 
+    /**
+     * @brief Calculates the index into the page table with the given level, which leads to this virtual page.
+     *
+     * @param level Level of the page table we want to calculate the index for.
+     * @return Index into the page table with the given level.
+     */
+    auto get_level_index(page_table::level level) const -> uint64_t;
+
     /**
      * @brief Defaulted equals operator.
      */
@@ -47,4 +56,4 @@ namespace teachos::arch::memory::paging
   };
 }  // namespace teachos::arch::memory::paging
 
-#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_VIRTUAL_PAGE_HPP
\ No newline at end of file
+#endif  // TEACHOS_ARCH_X86_64_MEMORY_PAGING_VIRTUAL_PAGE_HPP
diff --git a/arch/x86_64/src/memory/paging/page_table.cpp b/arch/x86_64/src/memory/paging/page_table.cpp
index 8345161..9857294 100644
--- a/arch/x86_64/src/memory/paging/page_table.cpp
+++ b/arch/x86_64/src/memory/paging/page_table.cpp
@@ -26,12 +26,8 @@ namespace teachos::arch::memory::paging
     exception_handling::assert(current_level != LEVEL1,
                                "[Page Table] Attempted to call next_table on level 1 page table");
     auto address = next_table_address(table_index);
-
-    if (address.has_value())
-    {
-      current_table = reinterpret_cast<table_content *>(address.value());
-      current_level = static_cast<level>(current_level - 1U);
-    }
+    current_table = reinterpret_cast<table_content *>(address.value());
+    current_level = static_cast<level>(current_level - 1U);
   }
 
   auto page_table::operator[](std::size_t index) -> entry &
diff --git a/arch/x86_64/src/memory/paging/virtual_page.cpp b/arch/x86_64/src/memory/paging/virtual_page.cpp
index 3fb6caf..dcdec7f 100644
--- a/arch/x86_64/src/memory/paging/virtual_page.cpp
+++ b/arch/x86_64/src/memory/paging/virtual_page.cpp
@@ -19,4 +19,9 @@ namespace teachos::arch::memory::paging
   }
 
   auto virtual_page::start_address() const -> uint64_t { return page_number * allocator::PAGE_FRAME_SIZE; }
+
+  auto virtual_page::get_level_index(page_table::level level) const -> uint64_t
+  {
+    return (start_address() >> (level * 9U)) & 0x1FF;
+  }
 }  // namespace teachos::arch::memory::paging
-- 
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