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 #include <linux/kexec.h>
  22
  23 int panic_timeout;
  24 int panic_on_oops;
  25 int tainted;
  26
  27 EXPORT_SYMBOL(panic_timeout);
  28
  29 struct notifier_block *panic_notifier_list;
  30
  31 EXPORT_SYMBOL(panic_notifier_list);
  32
  33 static int __init panic_setup(char *str)
  34 {
  35         panic_timeout = simple_strtoul(str, NULL, 0);
  36         return 1;
  37 }
  38 __setup("panic=", panic_setup);
  39
  40 static long no_blink(long time)
  41 {
  42         return 0;
  43 }
  44
  45 /* Returns how long it waited in ms */
  46 long (*panic_blink)(long time);
  47 EXPORT_SYMBOL(panic_blink);
  48
  49 /**
  50  *      panic - halt the system
  51  *      @fmt: The text string to print
  52  *
  53  *      Display a message, then perform cleanups.
  54  *
  55  *      This function never returns.
  56  */
  57
  58 NORET_TYPE void panic(const char * fmt, ...)
  59 {
  60         long i;
  61         static char buf[1024];
  62         va_list args;
  63 #if defined(CONFIG_S390)
  64         unsigned long caller = (unsigned long) __builtin_return_address(0);
  65 #endif
  66
  67         /*
  68          * It's possible to come here directly from a panic-assertion and not
  69          * have preempt disabled. Some functions called from here want
  70          * preempt to be disabled. No point enabling it later though...
  71          */
  72         preempt_disable();
  73
  74         bust_spinlocks(1);
  75         va_start(args, fmt);
  76         vsnprintf(buf, sizeof(buf), fmt, args);
  77         va_end(args);
  78         printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
  79         bust_spinlocks(0);
  80
  81         /*
  82          * If we have crashed and we have a crash kernel loaded let it handle
  83          * everything else.
  84          * Do we want to call this before we try to display a message?
  85          */
  86         crash_kexec(NULL);
  87
  88 #ifdef CONFIG_SMP
  89         /*
  90          * Note smp_send_stop is the usual smp shutdown function, which
  91          * unfortunately means it may not be hardened to work in a panic
  92          * situation.
  93          */
  94         smp_send_stop();
  95 #endif
  96
  97         notifier_call_chain(&panic_notifier_list, 0, buf);
  98
  99         if (!panic_blink)
 100                 panic_blink = no_blink;
 101
 102         if (panic_timeout > 0) {
 103                 /*
 104                  * Delay timeout seconds before rebooting the machine.
 105                  * We can't use the "normal" timers since we just panicked..
 106                  */
 107                 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
 108                 for (i = 0; i < panic_timeout*1000; ) {
 109                         touch_nmi_watchdog();
 110                         i += panic_blink(i);
 111                         mdelay(1);
 112                         i++;
 113                 }
 114                 /*      This will not be a clean reboot, with everything
 115                  *      shutting down.  But if there is a chance of
 116                  *      rebooting the system it will be rebooted.
 117                  */
 118                 emergency_restart();
 119         }
 120 #ifdef __sparc__
 121         {
 122                 extern int stop_a_enabled;
 123                 /* Make sure the user can actually press Stop-A (L1-A) */
 124                 stop_a_enabled = 1;
 125                 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
 126         }
 127 #endif
 128 #if defined(CONFIG_S390)
 129         disabled_wait(caller);
 130 #endif
 131         local_irq_enable();
 132         for (i = 0;;) {
 133                 i += panic_blink(i);
 134                 mdelay(1);
 135                 i++;
 136         }
 137 }
 138
 139 EXPORT_SYMBOL(panic);
 140
 141 /**
 142  *      print_tainted - return a string to represent the kernel taint state.
 143  *
 144  *  'P' - Proprietary module has been loaded.
 145  *  'F' - Module has been forcibly loaded.
 146  *  'S' - SMP with CPUs not designed for SMP.
 147  *  'R' - User forced a module unload.
 148  *  'M' - Machine had a machine check experience.
 149  *  'B' - System has hit bad_page.
 150  *
 151  *      The string is overwritten by the next call to print_taint().
 152  */
 153
 154 const char *print_tainted(void)
 155 {
 156         static char buf[20];
 157         if (tainted) {
 158                 snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c",
 159                         tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 160                         tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 161                         tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
 162                         tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
 163                         tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
 164                         tainted & TAINT_BAD_PAGE ? 'B' : ' ');
 165         }
 166         else
 167                 snprintf(buf, sizeof(buf), "Not tainted");
 168         return(buf);
 169 }
 170
 171 void add_taint(unsigned flag)
 172 {
 173         tainted |= flag;
 174 }
 175 EXPORT_SYMBOL(add_taint);