very good this is

1 files changed, 87 insertions, 0 deletions

diff --git a/kernel/inc/mm.h b/kernel/inc/mm.h
new file mode 100644
index 0000000..00d9e4b
--- /dev/null
+++ b/kernel/inc/mm.h
@@ -0,0 +1,87 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#ifndef PAGING_H
+#define PAGING_H
+
+#include <boot.h>
+#include <def.h>
+
+/**
+ * Physical
+ */
+
+/**
+ * Virtual
+ */
+
+#define PAGE_SIZE 0x1000
+#define PAGE_COUNT 1024
+#define PAGE_ALIGN(x) ((x) + PAGE_SIZE - ((x) % PAGE_SIZE))
+#define PAGE_ALIGNED(x) ((x) % PAGE_SIZE == 0)
+#define PAGE_ALIGN_UP(x) (((x) % PAGE_SIZE == 0) ? (x) : (x) + PAGE_SIZE - ((x) % PAGE_SIZE))
+#define PAGE_ALIGN_DOWN(x) ((x) - ((x) % PAGE_SIZE))
+
+union page_table_entry {
+	struct PACKED {
+		u32 present : 1;
+		u32 writable : 1;
+		u32 user : 1;
+		u32 write_through : 1;
+		u32 cache_disable : 1;
+		u32 accessed : 1;
+		u32 dirty : 1;
+		u32 attribute : 1;
+		u32 global : 1;
+		u32 available : 3;
+		u32 address : 20;
+	} bits;
+	u32 uint;
+} PACKED;
+
+struct page_table {
+	union page_table_entry entries[PAGE_COUNT];
+} PACKED;
+
+union page_dir_entry {
+	struct PACKED {
+		u32 present : 1;
+		u32 writable : 1;
+		u32 user : 1;
+		u32 write_through : 1;
+		u32 cache_disable : 1;
+		u32 accessed : 1;
+		u32 reserved : 1;
+		u32 page_size : 1;
+		u32 global : 1;
+		u32 available : 3;
+		u32 address : 20;
+	} bits;
+	u32 uint;
+} PACKED;
+
+struct page_dir {
+	union page_dir_entry entries[PAGE_COUNT];
+} PACKED;
+
+void paging_install(struct mem_info *mem_info);
+
+/**
+ * Memory wrappers
+ */
+
+#define MEMORY_NONE (0 << 0)
+#define MEMORY_USER (1 << 0)
+#define MEMORY_CLEAR (1 << 1)
+#define memory_range(base, size) ((struct memory_range){ (base), (size) })
+
+struct memory_range {
+	u32 base;
+	u32 size;
+};
+
+struct page_dir *memory_dir_create(void);
+void memory_dir_switch(struct page_dir *dir);
+void memory_alloc(struct page_dir *dir, u32 size, u32 flags, u32 *out);
+struct page_dir *memory_kernel_dir(void);
+
+#endif