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_ARCH_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_ARCH_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); 176