/*
       *  linux/kernel/panic.c
       *
       *  Copyright (C) 1991, 1992  Linus Torvalds
       */
      
      /*
       * This function is used through-out the kernel (including mm and fs)
       * to indicate a major problem.
       */
      #include <linux/config.h>
      #include <linux/sched.h>
      #include <linux/delay.h>
      #include <linux/reboot.h>
      #include <linux/notifier.h>
      #include <linux/init.h>
      #include <linux/sysrq.h>
      #include <linux/interrupt.h>
      
      asmlinkage void sys_sync(void);	/* it's really int */
      extern void unblank_console(void);
      
      int panic_timeout;
      
      struct notifier_block *panic_notifier_list;
      
  27  static int __init panic_setup(char *str)
      {
      	panic_timeout = simple_strtoul(str, NULL, 0);
  30  	return 1;
      }
      
      __setup("panic=", panic_setup);
      
      /**
       *	panic - halt the system
       *	@fmt: The text string to print
       *
       *	Display a message, then unblank the console and perform
       *	cleanups. Functions in the panic notifier list are called
       *	after the filesystem cache is flushed (when possible).
       *
       *	This function never returns.
       */
       
  46  NORET_TYPE void panic(const char * fmt, ...)
      {
      	static char buf[1024];
      	va_list args;
      #if defined(CONFIG_ARCH_S390)
              unsigned long caller = (unsigned long) __builtin_return_address(0);
      #endif
      
      	va_start(args, fmt);
      	vsprintf(buf, fmt, args);
      	va_end(args);
      	printk(KERN_EMERG "Kernel panic: %s\n",buf);
  58  	if (in_interrupt())
      		printk(KERN_EMERG "In interrupt handler - not syncing\n");
  60  	else if (!current->pid)
      		printk(KERN_EMERG "In idle task - not syncing\n");
  62  	else
      		sys_sync();
      
      	unblank_console();
      
      #ifdef CONFIG_SMP
      	smp_send_stop();
      #endif
      
      	notifier_call_chain(&panic_notifier_list, 0, NULL);
      
  73  	if (panic_timeout > 0)
      	{
      		/*
      	 	 * Delay timeout seconds before rebooting the machine. 
      		 * We can't use the "normal" timers since we just panicked..
      	 	 */
      		printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
      		mdelay(panic_timeout*1000);
      		/*
      		 *	Should we run the reboot notifier. For the moment Im
      		 *	choosing not too. It might crash, be corrupt or do
      		 *	more harm than good for other reasons.
      		 */
      		machine_restart(NULL);
      	}
      #ifdef __sparc__
      	{
      		extern int stop_a_enabled;
      		/* Make sure the user can actually press L1-A */
      		stop_a_enabled = 1;
      		printk("Press L1-A to return to the boot prom\n");
      	}
      #endif
      #if defined(CONFIG_ARCH_S390)
              disabled_wait(caller);
      #endif
      	sti();
 100  	for(;;) {
      		CHECK_EMERGENCY_SYNC
      	}
      }