X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=src%2Fuserprog%2Ftss.c;h=709dd3a21241459ee59045f95f1cc6a57de72e9e;hb=4ae5b30e5eb0be98521235060001c2d6d9828345;hp=4e1dc004332549d4e976d60565f24055111131bd;hpb=f2f8875638593bd5365cfd6a5ba7c9578e52322f;p=pintos-anon

diff --git a/src/userprog/tss.c b/src/userprog/tss.c
index 4e1dc00..709dd3a 100644
--- a/src/userprog/tss.c
+++ b/src/userprog/tss.c
@@ -2,8 +2,9 @@
 #include <debug.h>
 #include <stddef.h>
 #include "userprog/gdt.h"
-#include "threads/mmu.h"
+#include "threads/thread.h"
 #include "threads/palloc.h"
+#include "threads/vaddr.h"
 
 /* The Task-State Segment (TSS).
 
@@ -43,9 +44,10 @@
        stack pointer to point to the new thread's kernel stack.
        (The call is in schedule_tail() in thread.c.)
 
-   See [IA32-v3] 6.2.1 for a description of the TSS and 5.12.1
-   for a description of when and how stack switching occurs
-   during an interrupt. */
+   See [IA32-v3a] 6.2.1 "Task-State Segment (TSS)" for a
+   description of the TSS.  See [IA32-v3a] 5.12.1 "Exception- or
+   Interrupt-Handler Procedures" for a description of when and
+   how stack switching occurs during an interrupt. */
 struct tss
   {
     uint16_t back_link, :16;
@@ -80,10 +82,10 @@ tss_init (void)
   /* Our TSS is never used in a call gate or task gate, so only a
      few fields of it are ever referenced, and those are the only
      ones we initialize. */
-  tss = palloc_get (PAL_ASSERT | PAL_ZERO);
-  tss->esp0 = ptov(0x20000);
+  tss = palloc_get_page (PAL_ASSERT | PAL_ZERO);
   tss->ss0 = SEL_KDSEG;
   tss->bitmap = 0xdfff;
+  tss_update ();
 }
 
 /* Returns the kernel TSS. */
@@ -94,10 +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;
 }