Console locking and better panic behavoir.

006f8758 · Silas Boyd-Wickizer · 05d36ff7 · 006f8758
--- a/console.c
+++ b/console.c
@@ -18,6 +18,8 @@

 #define BACKSPACE 0x100

+static int panicked = 0;
+
 static struct {
  struct spinlock lock;
  int locking;
@@ -52,14 +54,11 @@ printint(void (*putch) (void*, char), void *putarg,
 static void
 consputc(int c)
 {
-  // XXX(sbw)
-#if 0
  if(panicked){
    cli();
    for(;;)
      ;
  }
-#endif

  if(c == BACKSPACE){
    uartputc('\b'); uartputc(' '); uartputc('\b');
@@ -201,15 +200,20 @@ puts(const char *s)
 void __attribute__((noreturn))
 panic(const char *s)
 {
+  extern void sys_halt();
+
  cli();
+  
+  if (cons.locking)
+    acquire(&cons.lock);
  cons.locking = 0;
+
  cprintf("cpu%d: panic: ", mycpu()->id);
  cprintf(s);
  cprintf("\n");
-
-  extern void sys_halt();
+  panicked = 1;
+  // Never release cons.lock
  sys_halt();
-
  for(;;)
    ;
 }
@@ -323,11 +327,11 @@ void
 initconsole(void)
 {
  initlock(&cons.lock, "console");
+  cons.locking = 1;
+
  devsw[CONSOLE].write = consolewrite;
  devsw[CONSOLE].read = consoleread;

  picenable(IRQ_KBD);
  ioapicenable(IRQ_KBD, 0);
-  // XXX(sbw) enable once we setup %gs
-  cons.locking = 0;
 }