X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fuserprog%2Fprocess.c;h=36c1bd0582437d280e630788d605ab9f87409bd1;hb=691750d03ff70aa5cef5fba81fed82e3a941bf95;hp=08e78c683e0024af747573e9fb78e48d63aee4e2;hpb=f0612244c44f4b4f0bc79e3fc882e9f74bd4a3f4;p=pintos-anon

diff --git a/src/userprog/process.c b/src/userprog/process.c
index 08e78c6..36c1bd0 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -31,7 +31,7 @@ process_execute (const char *filename)
 
   /* Make a copy of FILENAME.
      Otherwise there's a race between the caller and load(). */
-  fn_copy = palloc_get (0);
+  fn_copy = palloc_get_page (0);
   if (fn_copy == NULL)
     return TID_ERROR;
   strlcpy (fn_copy, filename, PGSIZE);
@@ -39,7 +39,7 @@ process_execute (const char *filename)
   /* Create a new thread to execute FILENAME. */
   tid = thread_create (filename, PRI_DEFAULT, execute_thread, fn_copy);
   if (tid == TID_ERROR)
-    palloc_free (fn_copy); 
+    palloc_free_page (fn_copy); 
   return tid;
 }
 
@@ -62,7 +62,7 @@ execute_thread (void *filename_)
   success = load (filename, &if_.eip, &if_.esp);
 
   /* If load failed, quit. */
-  palloc_free (filename);
+  palloc_free_page (filename);
   if (!success) 
     thread_exit ();
 
@@ -82,17 +82,24 @@ execute_thread (void *filename_)
   NOT_REACHED ();
 }
 
-/* Destroys the user address space in T and frees all of its
-   resources. */
+/* Free the current process's resources. */
 void
-process_destroy (struct thread *t)
+process_exit (void)
 {
-  ASSERT (t != thread_current ());
-
-  if (t->pagedir != NULL) 
+  struct thread *cur = thread_current ();
+  uint32_t *pd;
+
+  /* Destroy the current process's page directory and switch back
+     to the kernel-only page directory.  We have to set
+     cur->pagedir to NULL before switching page directories, or a
+     timer interrupt might switch back to the process page
+     directory. */
+  pd = cur->pagedir;
+  if (pd != NULL) 
     {
-      pagedir_destroy (t->pagedir);
-      t->pagedir = NULL; 
+      cur->pagedir = NULL;
+      pagedir_activate (NULL);
+      pagedir_destroy (pd);
     }
 }
 
@@ -103,10 +110,11 @@ process_activate (void)
 {
   struct thread *t = thread_current ();
 
-  /* Activate T's page tables. */
+  /* Activate thread's page tables. */
   pagedir_activate (t->pagedir);
 
-  /* Set T's kernel stack for use in processing interrupts. */
+  /* Set thread's kernel stack for use in processing
+     interrupts. */
   tss_set_esp0 ((uint8_t *) t + PGSIZE);
 }
 
@@ -339,14 +347,14 @@ load_segment (struct file *file, const struct Elf32_Phdr *phdr)
          file into the page and zero the rest. */
       size_t read_bytes = filesz_left >= PGSIZE ? PGSIZE : filesz_left;
       size_t zero_bytes = PGSIZE - read_bytes;
-      uint8_t *kpage = palloc_get (PAL_USER);
+      uint8_t *kpage = palloc_get_page (PAL_USER);
       if (kpage == NULL)
         return false;
 
       /* Do the reading and zeroing. */
       if (file_read (file, kpage, read_bytes) != (int) read_bytes) 
         {
-          palloc_free (kpage);
+          palloc_free_page (kpage);
           return false; 
         }
       memset (kpage + read_bytes, 0, zero_bytes);
@@ -355,7 +363,7 @@ load_segment (struct file *file, const struct Elf32_Phdr *phdr)
       /* Add the page to the process's address space. */
       if (!install_page (upage, kpage)) 
         {
-          palloc_free (kpage);
+          palloc_free_page (kpage);
           return false; 
         }
     }
@@ -371,14 +379,14 @@ setup_stack (void **esp)
   uint8_t *kpage;
   bool success = false;
 
-  kpage = palloc_get (PAL_USER | PAL_ZERO);
+  kpage = palloc_get_page (PAL_USER | PAL_ZERO);
   if (kpage != NULL) 
     {
       success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
       if (success)
         *esp = PHYS_BASE;
       else
-        palloc_free (kpage);
+        palloc_free_page (kpage);
     }
   else
     printf ("failed to allocate process stack\n");