X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fuserprog%2Ftss.c;h=709dd3a21241459ee59045f95f1cc6a57de72e9e;hb=96d5454f0787f4d190291f823a545a035ccf40c3;hp=f103823bb869d765b9fb5e28e1a5bd4d8090f29f;hpb=f415a37905c57f61b444806bf84f5405184452aa;p=pintos-anon

diff --git a/src/userprog/tss.c b/src/userprog/tss.c
index f103823..709dd3a 100644
--- a/src/userprog/tss.c
+++ b/src/userprog/tss.c
@@ -2,6 +2,7 @@
 #include <debug.h>
 #include <stddef.h>
 #include "userprog/gdt.h"
+#include "threads/thread.h"
 #include "threads/palloc.h"
 #include "threads/vaddr.h"
 
@@ -82,9 +83,9 @@ tss_init (void)
      few fields of it are ever referenced, and those are the only
      ones we initialize. */
   tss = palloc_get_page (PAL_ASSERT | PAL_ZERO);
-  tss->esp0 = ptov(0x20000);
   tss->ss0 = SEL_KDSEG;
   tss->bitmap = 0xdfff;
+  tss_update ();
 }
 
 /* Returns the kernel TSS. */
@@ -95,10 +96,11 @@ tss_get (void)
   return tss;
 }
 
-/* Sets the ring 0 stack pointer in the TSS to ESP0. */
+/* Sets the ring 0 stack pointer in the TSS to point to the end
+   of the thread stack. */
 void
-tss_set_esp0 (uint8_t *esp0) 
+tss_update (void) 
 {
   ASSERT (tss != NULL);
-  tss->esp0 = esp0;
+  tss->esp0 = (uint8_t *) thread_current () + PGSIZE;
 }