diff --git a/src/threads/thread.c b/src/threads/thread.c
index c2944cc..abf50d4 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -134,6 +134,9 @@ thread_start (void)
                   t))
     PANIC ("Failed to initialise child results table for main thread.");
 
+  if (!hash_init (&shared_files, shared_file_hash, shared_file_less, NULL))
+    PANIC ("Failed to initialise shared pages table.");
+
   /* Create the idle thread. */
   struct semaphore idle_started;
   sema_init (&idle_started, 0);
diff --git a/src/vm/page.c b/src/vm/page.c
index f21a3a7..d8b31c7 100644
--- a/src/vm/page.c
+++ b/src/vm/page.c
@@ -1,15 +1,15 @@
 #include "page.h"
 #include <string.h>
-#include <stdio.h>
 #include "filesys/file.h"
 #include "threads/malloc.h"
 #include "threads/palloc.h"
 #include "userprog/process.h"
 #include "vm/frame.h"
 
-static struct hash shared_files;
-
 static struct shared_file_entry *shared_file_get (struct file *file);
+static unsigned shared_page_hash (const struct hash_elem *e, void *aux UNUSED);
+static bool shared_page_less (const struct hash_elem *a_,
+                              const struct hash_elem *b_, void *aux UNUSED);
 
 /* Hashing function needed for the SPT table. Returns a hash for an entry,
    based on its upage. */
@@ -135,14 +135,14 @@ shared_file_less (const struct hash_elem *a_, const struct hash_elem *b_,
 
 /* Hashing function needed for the shared pages table. Returns a hash for an
    entry based on its user virtual address (upage) pointer. */
-unsigned
+static unsigned
 shared_page_hash (const struct hash_elem *e, void *aux UNUSED)
 {
   return hash_ptr (hash_entry (e, struct shared_page_entry, elem)->upage);
 }
 
 /* Less function needed for the shared pages table. */
-bool
+static bool
 shared_page_less (const struct hash_elem *a_, const struct hash_elem *b_,
                   void *aux UNUSED)
 {
@@ -238,5 +238,5 @@ page_set_swap (struct thread *owner, void *upage, size_t swap_slot)
 size_t
 page_get_swap (struct thread *owner, void *upage)
 {
-
+  return 0;
 }
diff --git a/src/vm/page.h b/src/vm/page.h
index 6a9ffe3..312e481 100644
--- a/src/vm/page.h
+++ b/src/vm/page.h
@@ -4,6 +4,8 @@
 #include "threads/thread.h"
 #include "filesys/off_t.h"
 
+struct hash shared_files;
+
 enum page_type {
   PAGE_EXECUTABLE,
   PAGE_EMPTY
@@ -47,6 +49,12 @@ struct page_entry *page_insert (struct file *file, off_t ofs, void *upage,
 struct page_entry *page_get (void *upage);
 bool page_load (struct page_entry *page, bool writable);
 void page_cleanup (struct hash_elem *e, void *aux);
+
+unsigned shared_file_hash (const struct hash_elem *e, void *aux);
+bool shared_file_less (const struct hash_elem *a_, const struct hash_elem *b_,
+                       void *aux);
+struct shared_page_entry *shared_page_get (struct file *file, void *upage);
+
 void page_set_swap (struct thread *, void *, size_t);
 size_t page_get_swap (struct thread *, void *);