Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  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/module.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>

#include <linux/nmi.h>

#include <linux/kexec.h>

#include <linux/debug_locks.h>

#include <linux/random.h>

int panic_on_oops;

int tainted;

static int pause_on_oops;

static int pause_on_oops_flag;

static DEFINE_SPINLOCK(pause_on_oops_lock);

int panic_timeout;

ATOMIC_NOTIFIER_HEAD(panic_notifier_list);

EXPORT_SYMBOL(panic_notifier_list);

static int __init panic_setup(char *str)

{

        panic_timeout = simple_strtoul(str, NULL, 0);

        return 1;

}

__setup("panic=", panic_setup);

static long no_blink(long time)

{

        return 0;

}

/* Returns how long it waited in ms */

long (*panic_blink)(long time);

EXPORT_SYMBOL(panic_blink);

/**

 *      panic - halt the system

 *      @fmt: The text string to print

 *

 *      Display a message, then perform cleanups.

 *

 *      This function never returns.

 */

NORET_TYPE void panic(const char * fmt, ...)

{

        long i;

        static char buf[1024];

        va_list args;

#if defined(CONFIG_S390)

        unsigned long caller = (unsigned long) __builtin_return_address(0);

#endif

        /*

         * It's possible to come here directly from a panic-assertion and not

         * have preempt disabled. Some functions called from here want

         * preempt to be disabled. No point enabling it later though...

         */

        preempt_disable();

        bust_spinlocks(1);

        va_start(args, fmt);

        vsnprintf(buf, sizeof(buf), fmt, args);

        va_end(args);

        printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);

        bust_spinlocks(0);

        /*

         * If we have crashed and we have a crash kernel loaded let it handle

         * everything else.

         * Do we want to call this before we try to display a message?

         */

        crash_kexec(NULL);

#ifdef CONFIG_SMP

        /*

         * Note smp_send_stop is the usual smp shutdown function, which

         * unfortunately means it may not be hardened to work in a panic

         * situation.

         */

        smp_send_stop();

#endif

        atomic_notifier_call_chain(&panic_notifier_list, 0, buf);

        if (!panic_blink)

                panic_blink = no_blink;

        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);

                for (i = 0; i < panic_timeout*1000; ) {

                        touch_nmi_watchdog();

                        i += panic_blink(i);

                        mdelay(1);

                        i++;

                }

                /*      This will not be a clean reboot, with everything

                 *      shutting down.  But if there is a chance of

                 *      rebooting the system it will be rebooted.

                 */

                emergency_restart();

        }

#ifdef __sparc__

        {

                extern int stop_a_enabled;

                /* Make sure the user can actually press Stop-A (L1-A) */

                stop_a_enabled = 1;

                printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");

        }

#endif

#if defined(CONFIG_S390)

        disabled_wait(caller);

#endif

        local_irq_enable();

        for (i = 0;;) {

                touch_softlockup_watchdog();

                i += panic_blink(i);

                mdelay(1);

                i++;

        }

}

EXPORT_SYMBOL(panic);

/**

 *      print_tainted - return a string to represent the kernel taint state.

 *

 *  'P' - Proprietary module has been loaded.

 *  'F' - Module has been forcibly loaded.

 *  'S' - SMP with CPUs not designed for SMP.

 *  'R' - User forced a module unload.

 *  'M' - System experienced a machine check exception.

 *  'B' - System has hit bad_page.

 *  'U' - Userspace-defined naughtiness.

 *

 *      The string is overwritten by the next call to print_taint().

 */

const char *print_tainted(void)

{

        static char buf[20];

        if (tainted) {

                snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c",

                        tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',

                        tainted & TAINT_FORCED_MODULE ? 'F' : ' ',

                        tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',

                        tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',

                        tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',

                        tainted & TAINT_BAD_PAGE ? 'B' : ' ',

                        tainted & TAINT_USER ? 'U' : ' ',

                        tainted & TAINT_DIE ? 'D' : ' ');

        }

        else

                snprintf(buf, sizeof(buf), "Not tainted");

        return(buf);

}

void add_taint(unsigned flag)

{

        debug_locks = 0; /* can't trust the integrity of the kernel anymore */

        tainted |= flag;

}

EXPORT_SYMBOL(add_taint);

static int __init pause_on_oops_setup(char *str)

{

        pause_on_oops = simple_strtoul(str, NULL, 0);

        return 1;

}

__setup("pause_on_oops=", pause_on_oops_setup);

static void spin_msec(int msecs)

{

        int i;

        for (i = 0; i < msecs; i++) {

                touch_nmi_watchdog();

                mdelay(1);

        }

}

/*

 * It just happens that oops_enter() and oops_exit() are identically

 * implemented...

 */

static void do_oops_enter_exit(void)

{

        unsigned long flags;

        static int spin_counter;

        if (!pause_on_oops)

                return;

        spin_lock_irqsave(&pause_on_oops_lock, flags);

        if (pause_on_oops_flag == 0) {

                /* This CPU may now print the oops message */

                pause_on_oops_flag = 1;

        } else {

                /* We need to stall this CPU */

                if (!spin_counter) {

                        /* This CPU gets to do the counting */

                        spin_counter = pause_on_oops;

                        do {

                                spin_unlock(&pause_on_oops_lock);

                                spin_msec(MSEC_PER_SEC);

                                spin_lock(&pause_on_oops_lock);

                        } while (--spin_counter);

                        pause_on_oops_flag = 0;

                } else {

                        /* This CPU waits for a different one */

                        while (spin_counter) {

                                spin_unlock(&pause_on_oops_lock);

                                spin_msec(1);

                                spin_lock(&pause_on_oops_lock);

                        }

                }

        }

        spin_unlock_irqrestore(&pause_on_oops_lock, flags);

}

/*

 * Return true if the calling CPU is allowed to print oops-related info.  This

 * is a bit racy..

 */

int oops_may_print(void)

{

        return pause_on_oops_flag == 0;

}

/*

 * Called when the architecture enters its oops handler, before it prints

 * anything.  If this is the first CPU to oops, and it's oopsing the first time

 * then let it proceed.

 *

 * This is all enabled by the pause_on_oops kernel boot option.  We do all this

 * to ensure that oopses don't scroll off the screen.  It has the side-effect

 * of preventing later-oopsing CPUs from mucking up the display, too.

 *

 * It turns out that the CPU which is allowed to print ends up pausing for the

 * right duration, whereas all the other CPUs pause for twice as long: once in

 * oops_enter(), once in oops_exit().

 */

void oops_enter(void)

{

        debug_locks_off(); /* can't trust the integrity of the kernel anymore */

        do_oops_enter_exit();

}

/*

 * 64-bit random ID for oopses:

 */

static u64 oops_id;

static int init_oops_id(void)

{

        if (!oops_id)

                get_random_bytes(&oops_id, sizeof(oops_id));

        return 0;

}

late_initcall(init_oops_id);

/*

 * Called when the architecture exits its oops handler, after printing

 * everything.

 */

void oops_exit(void)

{

        do_oops_enter_exit();

        init_oops_id();

        printk(KERN_WARNING "---[ end trace %016llx ]---\n",

                (unsigned long long)oops_id);

}

#ifdef CONFIG_CC_STACKPROTECTOR

/*

 * Called when gcc's -fstack-protector feature is used, and

 * gcc detects corruption of the on-stack canary value

 */

void __stack_chk_fail(void)

{

        panic("stack-protector: Kernel stack is corrupted");

}

EXPORT_SYMBOL(__stack_chk_fail);

#endif