implement page table and use it for lazy loading of segments

1 files changed, 41 insertions, 0 deletions

diff --git a/vm/page.h b/vm/page.h
new file mode 100644
index 0000000..29159fb
--- /dev/null
+++ b/vm/page.h
@@ -0,0 +1,41 @@
+#ifndef VM_PAGE_H
+#define VM_PAGE_H
+
+#include <debug.h>
+#include "hash.h"
+#include "filesys/off_t.h"
+
+/* supplemental page table entry */
+struct page_table_entry
+{
+  void *uvaddr;
+  bool loaded;
+  enum
+  {
+    PAGE_SEGMENT,
+    PAGE_MEMORY_MAPPED_FILE,
+  } type;
+
+  union
+  {
+    struct segment
+    {
+      struct file *file;
+      off_t ofs;
+      uint32_t read_bytes;
+      uint32_t zero_bytes;
+      bool writable;
+    } segment;
+  };
+
+  struct hash_elem elem;
+};
+
+void page_table_init (struct hash *ht);
+void page_table_free (struct hash *ht);
+struct page_table_entry *page_table_fetch (struct hash *ht, void *uvaddr);
+bool page_table_insert_segment (struct file *file, off_t ofs, uint8_t *upage,
+    uint32_t read_bytes, uint32_t zero_bytes, bool writable);
+bool page_load (struct page_table_entry *pte);
+
+#endif