x86_64: port basic page and page table abstractions

2 files changed, 60 insertions, 0 deletions

diff --git a/kapi/include/kapi/memory.hpp b/kapi/include/kapi/memory.hpp
index 3daaa86..4279274 100644
--- a/kapi/include/kapi/memory.hpp
+++ b/kapi/include/kapi/memory.hpp
@@ -4,6 +4,7 @@
 #include "kapi/memory/address.hpp"          // IWYU pragma: export
 #include "kapi/memory/frame.hpp"            // IWYU pragma: export
 #include "kapi/memory/frame_allocator.hpp"  // IWYU pragma: export
+#include "kapi/memory/page.hpp"             // IWYU pragma: export
 
 namespace teachos::memory
 {
diff --git a/kapi/include/kapi/memory/page.hpp b/kapi/include/kapi/memory/page.hpp
new file mode 100644
index 0000000..2b8e52a
--- /dev/null
+++ b/kapi/include/kapi/memory/page.hpp
@@ -0,0 +1,59 @@
+#ifndef TEACHOS_KAPI_MEMORY_PAGE_HPP
+#define TEACHOS_KAPI_MEMORY_PAGE_HPP
+
+#include "kapi/memory/address.hpp"
+
+#include <compare>
+#include <cstddef>
+
+namespace teachos::memory
+{
+
+  extern std::size_t const PLATFORM_PAGE_SIZE;
+
+  struct page
+  {
+    constexpr page() = default;
+
+    explicit constexpr page(std::size_t number)
+        : m_number{number}
+    {}
+
+    /**
+     * @brief Returns the virtual page the given address is contained in.
+     *
+     * @param address Linear address we want to get the corresponding virtual page for.
+     * @return Page the given address is contained in.
+     */
+    constexpr auto static containing(linear_address address) noexcept -> page
+    {
+      return page{address.raw() / PLATFORM_PAGE_SIZE};
+    }
+
+    /**
+     * @brief Get the start address of this virtual page.
+     *
+     * @return Start address of the virtual page.
+     */
+    [[nodiscard]] constexpr auto start_address() const noexcept -> linear_address
+    {
+      return linear_address{m_number * PLATFORM_PAGE_SIZE};
+    }
+
+    /**
+     * @brief Check if this page refers to the same page as @p other.
+     */
+    constexpr auto operator==(page const & other) const noexcept -> bool = default;
+
+    /**
+     * @brief Lexicographically compare this page to @p other.
+     */
+    constexpr auto operator<=>(page const & other) const noexcept -> std::strong_ordering = default;
+
+  private:
+    std::size_t m_number{};
+  };
+
+}  // namespace teachos::memory
+
+#endif
\ No newline at end of file