4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
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>
25 static int pause_on_oops;
26 static int pause_on_oops_flag;
27 static DEFINE_SPINLOCK(pause_on_oops_lock);
31 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
33 EXPORT_SYMBOL(panic_notifier_list);
35 static int __init panic_setup(char *str)
37 panic_timeout = simple_strtoul(str, NULL, 0);
40 __setup("panic=", panic_setup);
42 static long no_blink(long time)
47 /* Returns how long it waited in ms */
48 long (*panic_blink)(long time);
49 EXPORT_SYMBOL(panic_blink);
52 * panic - halt the system
53 * @fmt: The text string to print
55 * Display a message, then perform cleanups.
57 * This function never returns.
60 NORET_TYPE void panic(const char * fmt, ...)
63 static char buf[1024];
65 #if defined(CONFIG_S390)
66 unsigned long caller = (unsigned long) __builtin_return_address(0);
70 * It's possible to come here directly from a panic-assertion and not
71 * have preempt disabled. Some functions called from here want
72 * preempt to be disabled. No point enabling it later though...
78 vsnprintf(buf, sizeof(buf), fmt, args);
80 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
84 * If we have crashed and we have a crash kernel loaded let it handle
86 * Do we want to call this before we try to display a message?
92 * Note smp_send_stop is the usual smp shutdown function, which
93 * unfortunately means it may not be hardened to work in a panic
99 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
102 panic_blink = no_blink;
104 if (panic_timeout > 0) {
106 * Delay timeout seconds before rebooting the machine.
107 * We can't use the "normal" timers since we just panicked..
109 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
110 #ifdef CONFIG_BOOTSPLASH
112 extern int splash_verbose(void);
113 (void)splash_verbose();
116 for (i = 0; i < panic_timeout*1000; ) {
117 touch_nmi_watchdog();
122 /* This will not be a clean reboot, with everything
123 * shutting down. But if there is a chance of
124 * rebooting the system it will be rebooted.
130 extern int stop_a_enabled;
131 /* Make sure the user can actually press Stop-A (L1-A) */
133 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
136 #if defined(CONFIG_S390)
137 disabled_wait(caller);
140 #ifdef CONFIG_BOOTSPLASH
142 extern int splash_verbose(void);
143 (void)splash_verbose();
147 touch_softlockup_watchdog();
154 EXPORT_SYMBOL(panic);
157 * print_tainted - return a string to represent the kernel taint state.
159 * 'P' - Proprietary module has been loaded.
160 * 'F' - Module has been forcibly loaded.
161 * 'S' - SMP with CPUs not designed for SMP.
162 * 'R' - User forced a module unload.
163 * 'M' - Machine had a machine check experience.
164 * 'B' - System has hit bad_page.
165 * 'U' - Unsuported modules loaded.
166 * 'X' - Modules with external support loaded.
168 * The string is overwritten by the next call to print_taint().
171 const char *print_tainted(void)
175 snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c",
176 tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
177 tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
178 tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
179 tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
180 tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
181 tainted & TAINT_BAD_PAGE ? 'B' : ' ',
182 tainted & TAINT_NO_SUPPORT ? 'U' :
183 (tainted & TAINT_EXTERNAL_SUPPORT ? 'X' : ' '));
186 snprintf(buf, sizeof(buf), "Not tainted");
190 void add_taint(unsigned flag)
194 EXPORT_SYMBOL(add_taint);
196 static int __init pause_on_oops_setup(char *str)
198 pause_on_oops = simple_strtoul(str, NULL, 0);
201 __setup("pause_on_oops=", pause_on_oops_setup);
203 static void spin_msec(int msecs)
207 for (i = 0; i < msecs; i++) {
208 touch_nmi_watchdog();
214 * It just happens that oops_enter() and oops_exit() are identically
217 static void do_oops_enter_exit(void)
220 static int spin_counter;
225 spin_lock_irqsave(&pause_on_oops_lock, flags);
226 if (pause_on_oops_flag == 0) {
227 /* This CPU may now print the oops message */
228 pause_on_oops_flag = 1;
230 /* We need to stall this CPU */
232 /* This CPU gets to do the counting */
233 spin_counter = pause_on_oops;
235 spin_unlock(&pause_on_oops_lock);
236 spin_msec(MSEC_PER_SEC);
237 spin_lock(&pause_on_oops_lock);
238 } while (--spin_counter);
239 pause_on_oops_flag = 0;
241 /* This CPU waits for a different one */
242 while (spin_counter) {
243 spin_unlock(&pause_on_oops_lock);
245 spin_lock(&pause_on_oops_lock);
249 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
253 * Return true if the calling CPU is allowed to print oops-related info. This
256 int oops_may_print(void)
258 return pause_on_oops_flag == 0;
262 * Called when the architecture enters its oops handler, before it prints
263 * anything. If this is the first CPU to oops, and it's oopsing the first time
264 * then let it proceed.
266 * This is all enabled by the pause_on_oops kernel boot option. We do all this
267 * to ensure that oopses don't scroll off the screen. It has the side-effect
268 * of preventing later-oopsing CPUs from mucking up the display, too.
270 * It turns out that the CPU which is allowed to print ends up pausing for the
271 * right duration, whereas all the other CPUs pause for twice as long: once in
272 * oops_enter(), once in oops_exit().
274 void oops_enter(void)
276 do_oops_enter_exit();
280 * Called when the architecture exits its oops handler, after printing
285 do_oops_enter_exit();