Break TSS out of GDT.

[pintos-anon] / src / userprog / addrspace.c

diff --git a/src/userprog/addrspace.c b/src/userprog/addrspace.c
index 3837d4ed00a6e6edce942bdd2dcd25840041acee..1170f16ab92a7f61f1a93ad381ea49ff38208e63 100644 (file)
--- a/src/userprog/addrspace.c
+++ b/src/userprog/addrspace.c
@@ -3,11 +3,13 @@
 #include "debug.h"
 #include "file.h"
 #include "filesys.h"
+#include "init.h"
 #include "lib.h"
 #include "mmu.h"
-#include "malloc.h"
 #include "paging.h"
 #include "palloc.h"
+#include "thread.h"
+#include "tss.h"
 
 /* We load ELF binaries.  The following definitions are taken
    from the ELF specification more-or-less verbatim. */
@@ -79,14 +81,29 @@ struct Elf32_Phdr
         } while (0)
 
 static bool
-load_segment (struct addrspace *as, struct file *file,
+install_page (struct thread *t, void *upage, void *kpage)
+{
+  /* Verify that there's not already a page at that virtual
+     address, then map our page there. */
+  if (pagedir_get_page (t->pagedir, upage) == NULL
+      && pagedir_set_page (t->pagedir, upage, kpage, true))
+    return true;
+  else
+    {
+      palloc_free (kpage);
+      return false;
+    }
+}
+
+static bool
+load_segment (struct thread *t, struct file *file,
               const struct Elf32_Phdr *phdr) 
 {
   void *start, *end;
   uint8_t *upage;
   off_t filesz_left;
 
-  ASSERT (as != NULL);
+  ASSERT (t != NULL);
   ASSERT (file != NULL);
   ASSERT (phdr != NULL);
   ASSERT (phdr->p_type == PT_LOAD);
@@ -132,34 +149,49 @@ load_segment (struct addrspace *as, struct file *file,
       memset (kpage + read_bytes, 0, zero_bytes);
       filesz_left -= read_bytes;
 
-      if (pagedir_get_page (as->pagedir, upage))
-        {
-          palloc_free (kpage);
-          return false;
-        }
-      pagedir_set_page (as->pagedir, upage, kpage, true);
+      if (!install_page (t, upage, kpage))
+        return false;
     }
 
   return true;
 }
 
+static bool
+setup_stack (struct thread *t) 
+{
+  uint8_t *kpage = palloc_get (PAL_ZERO);
+  if (kpage == NULL)
+    {
+      printk ("failed to allocate process stack\n");
+      return false;
+    }
+
+  return install_page (t, ((uint8_t *) PHYS_BASE) - PGSIZE, kpage);
+}
+
 bool
-addrspace_load (struct addrspace *as, const char *filename) 
+addrspace_load (struct thread *t, const char *filename,
+                void (**start) (void)) 
 {
   struct Elf32_Ehdr ehdr;
-  struct file *file = NULL;
+  struct file file;
+  bool file_open = false;
   off_t file_ofs;
   bool success = false;
   int i;
 
-  as->pagedir = pagedir_create ();
+  /* Allocate page directory. */
+  t->pagedir = pagedir_create ();
+  if (t->pagedir == NULL)
+    LOAD_ERROR (("page directory allocation failed"));
 
-  file = filesys_open (filename);
-  if (file == NULL)
+  /* Open executable file. */
+  file_open = filesys_open (filename, &file);
+  if (!file_open)
     LOAD_ERROR (("open failed"));
 
   /* Read and verify executable header. */
-  if (file_read (file, &ehdr, sizeof ehdr) != sizeof ehdr) 
+  if (file_read (&file, &ehdr, sizeof ehdr) != sizeof ehdr) 
     LOAD_ERROR (("error reading executable header"));
   if (memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7) != 0)
     LOAD_ERROR (("file is not ELF"));
@@ -177,26 +209,20 @@ addrspace_load (struct addrspace *as, const char *filename)
 
   /* Read program headers. */
   file_ofs = ehdr.e_phoff;
-  printk ("e_phnum=%d\n", ehdr.e_phnum);
   for (i = 0; i < ehdr.e_phnum; i++) 
     {
       struct Elf32_Phdr phdr;
 
-      file_seek (file, file_ofs);
-      if (file_read (file, &phdr, sizeof phdr) != sizeof phdr)
+      file_seek (&file, file_ofs);
+      if (file_read (&file, &phdr, sizeof phdr) != sizeof phdr)
         LOAD_ERROR (("error reading program header"));
-      printk ("%x: %08x, %08x %08x %08x %05x %05x\n",
-              file_tell (file),
-              phdr.p_type,
-              phdr.p_offset, phdr.p_vaddr, phdr.p_paddr,
-              phdr.p_filesz, phdr.p_memsz);
       file_ofs += sizeof phdr;
       switch (phdr.p_type) 
         {
         case PT_NULL:
         case PT_NOTE:
         case PT_PHDR:
-        case PT_STACK: /* Stack segment. */
+        case PT_STACK:
           /* Ignore this segment. */
           break;
         case PT_DYNAMIC:
@@ -209,24 +235,45 @@ addrspace_load (struct addrspace *as, const char *filename)
           printk ("unknown ELF segment type %08x\n", phdr.p_type);
           break;
         case PT_LOAD:
-          if (!load_segment (as, file, &phdr))
+          if (!load_segment (t, &file, &phdr))
             goto error;
           break;
         }
     }
+
+  /* Set up stack. */
+  if (!setup_stack (t))
+    goto error;
+
+  /* Start address. */
+  *start = (void (*) (void)) ehdr.e_entry;
+
   success = true;
 
  error:
-  if (file != NULL)
-    file_close (file);
+  if (file_open)
+    file_close (&file);
   if (!success) 
-    addrspace_destroy (as);
+    addrspace_destroy (t);
   return success;
 }
 
 void
-addrspace_destroy (struct addrspace *as)
+addrspace_destroy (struct thread *t)
+{
+  if (t->pagedir != NULL) 
+    {
+      pagedir_destroy (t->pagedir);
+      t->pagedir = NULL; 
+    }
+}
+
+void
+addrspace_activate (struct thread *t)
 {
-  if (as != NULL && as->pagedir != NULL) 
-    pagedir_destroy (as->pagedir); 
+  ASSERT (t != NULL);
+  
+  if (t->pagedir != NULL)
+    pagedir_activate (t->pagedir);
+  tss_set_esp0 ((uint8_t *) t + PGSIZE);
 }