From 5449acc193f96d2ffaeb224aad5cea16bf753cdb Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 10 Sep 2026 08:53:57 +0200
Subject: x86_64: replace raw pointers with observer_ptr

---
 kapi/kapi/memory.hpp             |  8 ++++++--
 kapi/kapi/memory/address.hpp     | 24 +++++++++++++++++++++---
 kapi/kapi/memory/page_mapper.hpp |  5 +++--
 3 files changed, 30 insertions(+), 7 deletions(-)

(limited to 'kapi')

diff --git a/kapi/kapi/memory.hpp b/kapi/kapi/memory.hpp
index 8ad8d6ec..4b14b553 100644
--- a/kapi/kapi/memory.hpp
+++ b/kapi/kapi/memory.hpp
@@ -9,6 +9,8 @@
 #include <kapi/memory/page.hpp>             // IWYU pragma: export
 #include <kapi/memory/page_mapper.hpp>      // IWYU pragma: export
 
+#include <kstd/memory.hpp>
+
 #include <cstddef>
 #include <optional>
 #include <utility>
@@ -72,7 +74,8 @@ namespace kapi::memory
   //! @param frame The frame to map the page into.
   //! @param flags The flags to apply to this mapping.
   //! @return A pointer to the first byte of the mapped page.
-  auto map(page page, frame frame, page_mapper::flags flags = page_mapper::flags::empty) -> std::byte *;
+  auto map(page page, frame frame, page_mapper::flags flags = page_mapper::flags::empty)
+      -> kstd::observer_ptr<std::byte>;
 
   //! Unmap a page.
   //!
@@ -103,7 +106,8 @@ namespace kapi::memory
   //! @param region The region to map.
   //! @param hw_base The base of the hardware region.
   //! @param flags The flags to apply.
-  auto map_mmio_region(mmio_region region, physical_address hw_base, page_mapper::flags flags = {}) -> std::byte *;
+  auto map_mmio_region(mmio_region region, physical_address hw_base, page_mapper::flags flags = {})
+      -> kstd::observer_ptr<std::byte>;
 
   //! Release a Memory-mapped I/O region.
   //!
diff --git a/kapi/kapi/memory/address.hpp b/kapi/kapi/memory/address.hpp
index 5b84a381..0fab06e0 100644
--- a/kapi/kapi/memory/address.hpp
+++ b/kapi/kapi/memory/address.hpp
@@ -4,6 +4,7 @@
 // IWYU pragma: private, include <kapi/memory.hpp>
 
 #include <kstd/format.hpp>
+#include <kstd/memory.hpp>
 #include <kstd/units.hpp>
 
 #include <bit>
@@ -47,13 +48,20 @@ namespace kapi::memory
     //! Construct an address representing the given pointer value.
     //!
     //! @param pointer The pointer value to initialize this address with.
-    explicit address(std::byte * pointer) noexcept
-        : m_value{std::bit_cast<std::uintptr_t>(pointer)}
+    explicit address(std::byte const * pointer) noexcept
+        : m_value{reinterpret_cast<std::uintptr_t>(pointer)}
+    {}
+
+    //! Construct an address representing the given pointer value.
+    //!
+    //! @param pointer The pointer value to initialize this address with.
+    explicit address(kstd::observer_ptr<std::byte const> pointer) noexcept
+        : m_value{reinterpret_cast<std::uintptr_t>(pointer.get())}
     {}
 
     //! Convert this address into a C++ pointer.
     //!
-    //! @tparam T The type of the object this address should refer to.
+    //! @tparam ObjectType The type of the object the pointer should refer to.
     //! @return This address as a typed pointer to the given type.
     template<typename ObjectType>
     explicit operator ObjectType *() const noexcept
@@ -61,6 +69,16 @@ namespace kapi::memory
       return std::bit_cast<ObjectType *>(m_value);
     }
 
+    //! Convert this address into an observer pointer.
+    //!
+    //! @tparam ObjectType The type of the object the pointer should refer to.
+    //! @return An observer pointer pointing to the memory location represented by this address.
+    template<typename ObjectType>
+    explicit operator kstd::observer_ptr<ObjectType>() const noexcept
+    {
+      return kstd::make_observer(reinterpret_cast<ObjectType *>(m_value));
+    }
+
     //! Create a new address n beyond this one.
     //!
     //! @param n The amount to add to this address.
diff --git a/kapi/kapi/memory/page_mapper.hpp b/kapi/kapi/memory/page_mapper.hpp
index 3deb4702..a310e209 100644
--- a/kapi/kapi/memory/page_mapper.hpp
+++ b/kapi/kapi/memory/page_mapper.hpp
@@ -7,6 +7,7 @@
 #include <kapi/memory/page.hpp>
 
 #include <kstd/bitfield_enum.hpp>
+#include <kstd/memory.hpp>
 
 #include <cstddef>
 #include <cstdint>
@@ -45,7 +46,7 @@ namespace kapi::memory
     //! @param frame The frame to map the page into.
     //! @param flags The flags to map the page with.
     //! @return A pointer to the first byte of mapped page.
-    virtual auto map(page page, frame frame, flags flags) -> std::byte * = 0;
+    virtual auto map(page page, frame frame, flags flags) -> kstd::observer_ptr<std::byte> = 0;
 
     //! Unmap the given page.
     //!
@@ -70,7 +71,7 @@ namespace kapi::memory
     //! @param flags The flags to map the page with.
     //! @return A pointer to the first T in the page.
     template<typename T>
-    [[nodiscard]] auto map_as(page page, frame frame, flags flags) -> T *
+    [[nodiscard]] auto map_as(page page, frame frame, flags flags) -> kstd::observer_ptr<T>
     {
       return std::bit_cast<T *>(map(page, frame, flags));
     }
-- 
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