Make backtraces slightly more reliable.

[pintos-anon] / src / lib / debug.c

diff --git a/src/lib/debug.c b/src/lib/debug.c
index 66e911926a4cced405ac13b13d79a4a24dd40f14..1dc1bf8fd69db3c5651654620dcf79200cbf6844 100644 (file)
--- a/src/lib/debug.c
+++ b/src/lib/debug.c
@@ -4,53 +4,6 @@
 #include <stddef.h>
 #include <stdio.h>
 #include <string.h>
-#ifdef KERNEL
-#include "threads/init.h"
-#include "threads/interrupt.h"
-#include "devices/serial.h"
-#else
-#include <syscall.h>
-#endif
-
-/* Halts the OS or user program, printing the source file name,
-   line number, and function name, plus a user-specific
-   message. */
-void
-debug_panic (const char *file, int line, const char *function,
-             const char *message, ...)
-{
-  va_list args;
-
-#ifdef KERNEL
-  intr_disable ();
-#endif
-
-#ifdef KERNEL
-  printf ("Kernel PANIC at %s:%d in %s(): ", file, line, function);
-#else
-  printf ("User process panic at %s:%d in %s(): ", file, line, function);
-#endif
-
-  va_start (args, message);
-  vprintf (message, args);
-  printf ("\n");
-  va_end (args);
-
-  debug_backtrace ();
-
-  printf ("The `backtrace' program can make call stacks useful.\n"
-          "Read \"Backtraces\" in the \"Debugging Tools\" chapter\n"
-          "of the Pintos documentation for more information.\n");
-  
-#ifdef KERNEL
-  serial_flush ();
-  if (power_off_when_done)
-    power_off ();
-  for (;;);
-#else
-  exit (1);
-#endif
-}
 
 /* Prints the call stack, that is, a list of addresses, one in
    each of the functions we are nested within.  gdb or addr2line
@@ -59,12 +12,21 @@ debug_panic (const char *file, int line, const char *function,
 void
 debug_backtrace (void) 
 {
+  static bool explained;
   void **frame;
   
   printf ("Call stack:");
   for (frame = __builtin_frame_address (0);
-       frame != NULL && frame[0] != NULL;
+       (uintptr_t) frame >= 0x1000 && frame[0] != NULL;
        frame = frame[0]) 
     printf (" %p", frame[1]);
   printf (".\n");
+
+  if (!explained) 
+    {
+      explained = true;
+      printf ("The `backtrace' program can make call stacks useful.\n"
+              "Read \"Backtraces\" in the \"Debugging Tools\" chapter\n"
+              "of the Pintos documentation for more information.\n");
+    }
 }