kernel/panic.c

   1 /*
   2  *  linux/kernel/panic.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  * This function is used through-out the kernel (including mm and fs)
   9  * to indicate a major problem.
  10  */
  11 #include <linux/config.h>
  12 #include <linux/module.h>
  13 #include <linux/sched.h>
  14 #include <linux/delay.h>
  15 #include <linux/reboot.h>
  16 #include <linux/notifier.h>
  17 #include <linux/init.h>
  18 #include <linux/sysrq.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/nmi.h>
  21
  22 int panic_timeout;
  23 int panic_on_oops;
  24 int tainted;
  25
  26 EXPORT_SYMBOL(panic_timeout);
  27
  28 struct notifier_block *panic_notifier_list;
  29
  30 EXPORT_SYMBOL(panic_notifier_list);
  31
  32 static int __init panic_setup(char *str)
  33 {
  34         panic_timeout = simple_strtoul(str, NULL, 0);
  35         return 1;
  36 }
  37 __setup("panic=", panic_setup);
  38
  39 static long no_blink(long time)
  40 {
  41         return 0;
  42 }
  43
  44 /* Returns how long it waited in ms */
  45 long (*panic_blink)(long time);
  46 EXPORT_SYMBOL(panic_blink);
  47
  48 /**
  49  *      panic - halt the system
  50  *      @fmt: The text string to print
  51  *
  52  *      Display a message, then perform cleanups.
  53  *
  54  *      This function never returns.
  55  */
  56
  57 NORET_TYPE void panic(const char * fmt, ...)
  58 {
  59         long i;
  60         static char buf[1024];
  61         va_list args;
  62 #if defined(CONFIG_ARCH_S390)
  63         unsigned long caller = (unsigned long) __builtin_return_address(0);
  64 #endif
  65
  66         bust_spinlocks(1);
  67         va_start(args, fmt);
  68         vsnprintf(buf, sizeof(buf), fmt, args);
  69         va_end(args);
  70         printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
  71         bust_spinlocks(0);
  72
  73 #ifdef CONFIG_SMP
  74         smp_send_stop();
  75 #endif
  76
  77         notifier_call_chain(&panic_notifier_list, 0, buf);
  78
  79         if (!panic_blink)
  80                 panic_blink = no_blink;
  81
  82         if (panic_timeout > 0)
  83         {
  84                 /*
  85                  * Delay timeout seconds before rebooting the machine.
  86                  * We can't use the "normal" timers since we just panicked..
  87                  */
  88                 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
  89                 for (i = 0; i < panic_timeout*1000; ) {
  90                         touch_nmi_watchdog();
  91                         i += panic_blink(i);
  92                         mdelay(1);
  93                         i++;
  94                 }
  95                 /*
  96                  *      Should we run the reboot notifier. For the moment Im
  97                  *      choosing not too. It might crash, be corrupt or do
  98                  *      more harm than good for other reasons.
  99                  */
 100                 machine_restart(NULL);
 101         }
 102 #ifdef __sparc__
 103         {
 104                 extern int stop_a_enabled;
 105                 /* Make sure the user can actually press Stop-A (L1-A) */
 106                 stop_a_enabled = 1;
 107                 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
 108         }
 109 #endif
 110 #if defined(CONFIG_ARCH_S390)
 111         disabled_wait(caller);
 112 #endif
 113         local_irq_enable();
 114         for (i = 0;;) {
 115                 i += panic_blink(i);
 116                 mdelay(1);
 117                 i++;
 118         }
 119 }
 120
 121 EXPORT_SYMBOL(panic);
 122
 123 /**
 124  *      print_tainted - return a string to represent the kernel taint state.
 125  *
 126  *  'P' - Proprietary module has been loaded.
 127  *  'F' - Module has been forcibly loaded.
 128  *  'S' - SMP with CPUs not designed for SMP.
 129  *  'R' - User forced a module unload.
 130  *  'M' - Machine had a machine check experience.
 131  *  'B' - System has hit bad_page.
 132  *
 133  *      The string is overwritten by the next call to print_taint().
 134  */
 135
 136 const char *print_tainted(void)
 137 {
 138         static char buf[20];
 139         if (tainted) {
 140                 snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c",
 141                         tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 142                         tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 143                         tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
 144                         tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
 145                         tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
 146                         tainted & TAINT_BAD_PAGE ? 'B' : ' ');
 147         }
 148         else
 149                 snprintf(buf, sizeof(buf), "Not tainted");
 150         return(buf);
 151 }
 152
 153 void add_taint(unsigned flag)
 154 {
 155         tainted |= flag;
 156 }
 157 EXPORT_SYMBOL(add_taint);