From 1274be88b61b685a7792e77fc38b90b8a30fcab7 Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Wed, 13 May 2026 15:46:07 +0800
Subject: feat: add Page structure and PageState enumeration for physical
 memory management

---
 na/include/lume/frame.h | 59 -------------------------------------------------
 na/include/lume/page.h  | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 59 deletions(-)
 delete mode 100644 na/include/lume/frame.h
 create mode 100644 na/include/lume/page.h

(limited to 'na')

diff --git a/na/include/lume/frame.h b/na/include/lume/frame.h
deleted file mode 100644
index 4424979..0000000
--- a/na/include/lume/frame.h
+++ /dev/null
@@ -1,59 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* Copyright (C) 2026 Richard Qin */
-
-#pragma once
-
-/*
- * Frame — Physical page frame descriptor
- *
- * Each Frame describes one 4KB physical page.  A flat array of Frame
- * structs (frame_map) covers all physical memory discovered via FDT.
- *
- * Memory layout is compressed using a union: only one of free/slab
- * metadata is valid at a time, determined by `state`.  The refcount
- * field is independent of the union to support COW sharing.
- *
- * Reference: docs/specs/pmm.md §3.1
- */
-
-#include <lume/types.h>
-#include <lume/list.h>
-#include <lume/atomic.h>
-
-/* Forward declaration — defined in slab module (Phase 2) */
-class KmemCache;
-
-enum class FrameState : uint8 {
-    Free,       // In Buddy free list
-    PcpCached,  // In Per-CPU cache (invisible to buddy coalescing)
-    Allocated,  // Handed out to Slab / VMM / user
-    Slab,       // Backing a Slab cache
-};
-
-struct Frame {
-    /*
-     * Reference count (atomic).
-     * Starts at 1 on allocation.  Incremented by fork() for COW pages.
-     * When decremented to 0, the frame is returned to the free pool.
-     */
-    lume::atomic<uint32> refcount;
-
-    FrameState state;   // Current usage state
-    uint8 order;        // Buddy order (0–10, i.e. 4KB–4MB)
-
-    union {
-        /* Valid when state == Free */
-        struct {
-            list_node free_link;  // Link into Buddy or PCP free list
-        } free;
-
-        /* Valid when state == Slab */
-        struct {
-            KmemCache* cache;     // Owning slab cache
-            uint32 obj_count;     // Number of allocated objects on this page
-            void* freelist;       // Head of in-page free object linked list
-        } slab;
-
-        /* state == Allocated: no extra metadata (yet) */
-    };
-};
diff --git a/na/include/lume/page.h b/na/include/lume/page.h
new file mode 100644
index 0000000..7f3f8d1
--- /dev/null
+++ b/na/include/lume/page.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+#pragma once
+
+/*
+ * Page — Physical page descriptor
+ *
+ * Each Page describes one 4KB physical page. A flat array of Page
+ * structs (page_map) covers all physical memory discovered via FDT.
+ *
+ * Memory layout is compressed using a union: only one of free/slab
+ * metadata is valid at a time, determined by `state`. The refcount
+ * field is independent of the union to support COW sharing.
+ *
+ * Reference: docs/specs/pmm.md §3.1
+ */
+
+#include <lume/types.h>
+#include <lume/list.h>
+#include <lume/atomic.h>
+
+/* Forward declaration — defined in slab module (Phase 2) */
+class KmemCache;
+
+enum class PageState : uint8 {
+    Free,       // In Buddy free list
+    PcpCached,  // In Per-CPU cache (invisible to buddy coalescing)
+    Allocated,  // Handed out to Slab / VMM / user
+    Slab,       // Backing a Slab cache
+};
+
+struct Page {
+    /*
+     * Reference count (atomic).
+     * Starts at 1 on allocation. Incremented by fork() for COW pages.
+     * When decremented to 0, the page is returned to the free pool.
+     */
+    lume::atomic<uint32> refcount;
+
+    PageState state;  // Current usage state
+    uint8 order;      // Buddy order (0–10, i.e. 4KB–4MB)
+
+    union {
+        /* Valid when state == Free */
+        struct {
+            list_node free_link;  // Link into Buddy or PCP free list
+        } free;
+
+        /* Valid when state == Slab */
+        struct {
+            KmemCache* cache;     // Owning slab cache
+            uint32 obj_count;     // Number of allocated objects on this page
+            void* freelist;       // Head of in-page free object linked list
+        } slab;
+
+        /* state == Allocated: no extra metadata (yet) */
+    };
+};
-- 
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