Implement Supplemental Page Table (SPT) per thread along with structure for its entries, w/ G

src/threads/thread.c

@@ -15,6 +15,7 @@
 #include "threads/switch.h"
 #include "threads/synch.h"
 #include "threads/vaddr.h"
+#include "vm/page.h"
 #ifdef USERPROG
 #include "userprog/process.h"
 #include "userprog/syscall.h"
@@ -264,7 +265,8 @@ thread_create (const char *name, int priority,
 
   if (!hash_init (&t->open_files, fd_hash, fd_less, NULL)
       || !hash_init (&t->child_results, process_result_hash,
-                     process_result_less, t))
+                     process_result_less, t)
+      || !hash_init (&t->pages, page_hash, page_less, NULL))
     {
       palloc_free_page (t);
       free (t->result);

src/threads/thread.h

@@ -135,6 +135,8 @@ struct thread
     /* Shared between thread.c and synch.c. */
     struct list_elem elem;              /* List element. */
 
+    struct hash pages;                  /* Table of open user pages. */
+
 #ifdef USERPROG
     /* Owned by userprog/process.c. */
     uint32_t *pagedir;                  /* Page directory. */