[mirror_ubuntu-artful-kernel.git] / drivers / char / sysrq.c

/* -*- linux-c -*-
 *
 *	$Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
 *
 *	Linux Magic System Request Key Hacks
 *
 *	(c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 *	based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
 *
 *	(c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
 *	overhauled to use key registration
 *	based upon discusions in irc://irc.openprojects.net/#kernelnewbies
 */

#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/tty.h>
#include <linux/mount.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <linux/reboot.h>
#include <linux/sysrq.h>
#include <linux/kbd_kern.h>
#include <linux/proc_fs.h>
#include <linux/quotaops.h>
#include <linux/perf_counter.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>		/* for fsync_bdev() */
#include <linux/swap.h>
#include <linux/spinlock.h>
#include <linux/vt_kern.h>
#include <linux/workqueue.h>
#include <linux/kexec.h>
#include <linux/irq.h>
#include <linux/hrtimer.h>
#include <linux/oom.h>

#include <asm/ptrace.h>
#include <asm/irq_regs.h>

/* Whether we react on sysrq keys or just ignore them */
int __read_mostly __sysrq_enabled = 1;

static int __read_mostly sysrq_always_enabled;

int sysrq_on(void)
{
	return __sysrq_enabled || sysrq_always_enabled;
}

/*
 * A value of 1 means 'all', other nonzero values are an op mask:
 */
static inline int sysrq_on_mask(int mask)
{
	return sysrq_always_enabled || __sysrq_enabled == 1 ||
						(__sysrq_enabled & mask);
}

static int __init sysrq_always_enabled_setup(char *str)
{
	sysrq_always_enabled = 1;
	printk(KERN_INFO "debug: sysrq always enabled.\n");

	return 1;
}

__setup("sysrq_always_enabled", sysrq_always_enabled_setup);


static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
{
	int i;
	i = key - '0';
	console_loglevel = 7;
	printk("Loglevel set to %d\n", i);
	console_loglevel = i;
}
static struct sysrq_key_op sysrq_loglevel_op = {
	.handler	= sysrq_handle_loglevel,
	.help_msg	= "loglevel0-8",
	.action_msg	= "Changing Loglevel",
	.enable_mask	= SYSRQ_ENABLE_LOG,
};

#ifdef CONFIG_VT
static void sysrq_handle_SAK(int key, struct tty_struct *tty)
{
	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
	schedule_work(SAK_work);
}
static struct sysrq_key_op sysrq_SAK_op = {
	.handler	= sysrq_handle_SAK,
	.help_msg	= "saK",
	.action_msg	= "SAK",
	.enable_mask	= SYSRQ_ENABLE_KEYBOARD,
};
#else
#define sysrq_SAK_op (*(struct sysrq_key_op *)0)
#endif

#ifdef CONFIG_VT
static void sysrq_handle_unraw(int key, struct tty_struct *tty)
{
	struct kbd_struct *kbd = &kbd_table[fg_console];

	if (kbd)
		kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
}
static struct sysrq_key_op sysrq_unraw_op = {
	.handler	= sysrq_handle_unraw,
	.help_msg	= "unRaw",
	.action_msg	= "Keyboard mode set to system default",
	.enable_mask	= SYSRQ_ENABLE_KEYBOARD,
};
#else
#define sysrq_unraw_op (*(struct sysrq_key_op *)0)
#endif /* CONFIG_VT */

#ifdef CONFIG_KEXEC
static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
{
	crash_kexec(get_irq_regs());
}
static struct sysrq_key_op sysrq_crashdump_op = {
	.handler	= sysrq_handle_crashdump,
	.help_msg	= "Crashdump",
	.action_msg	= "Trigger a crashdump",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};
#else
#define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
#endif

static void sysrq_handle_reboot(int key, struct tty_struct *tty)
{
	lockdep_off();
	local_irq_enable();
	emergency_restart();
}
static struct sysrq_key_op sysrq_reboot_op = {
	.handler	= sysrq_handle_reboot,
	.help_msg	= "reBoot",
	.action_msg	= "Resetting",
	.enable_mask	= SYSRQ_ENABLE_BOOT,
};

static void sysrq_handle_sync(int key, struct tty_struct *tty)
{
	emergency_sync();
}
static struct sysrq_key_op sysrq_sync_op = {
	.handler	= sysrq_handle_sync,
	.help_msg	= "Sync",
	.action_msg	= "Emergency Sync",
	.enable_mask	= SYSRQ_ENABLE_SYNC,
};

static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
{
	sysrq_timer_list_show();
}

static struct sysrq_key_op sysrq_show_timers_op = {
	.handler	= sysrq_handle_show_timers,
	.help_msg	= "show-all-timers(Q)",
	.action_msg	= "Show clockevent devices & pending hrtimers (no others)",
};

static void sysrq_handle_mountro(int key, struct tty_struct *tty)
{
	emergency_remount();
}
static struct sysrq_key_op sysrq_mountro_op = {
	.handler	= sysrq_handle_mountro,
	.help_msg	= "Unmount",
	.action_msg	= "Emergency Remount R/O",
	.enable_mask	= SYSRQ_ENABLE_REMOUNT,
};

#ifdef CONFIG_LOCKDEP
static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
{
	debug_show_all_locks();
}

static struct sysrq_key_op sysrq_showlocks_op = {
	.handler	= sysrq_handle_showlocks,
	.help_msg	= "show-all-locks(D)",
	.action_msg	= "Show Locks Held",
};
#else
#define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
#endif

#ifdef CONFIG_SMP
static DEFINE_SPINLOCK(show_lock);

static void showacpu(void *dummy)
{
	unsigned long flags;

	/* Idle CPUs have no interesting backtrace. */
	if (idle_cpu(smp_processor_id()))
		return;

	spin_lock_irqsave(&show_lock, flags);
	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	show_stack(NULL, NULL);
	spin_unlock_irqrestore(&show_lock, flags);
}

static void sysrq_showregs_othercpus(struct work_struct *dummy)
{
	smp_call_function(showacpu, NULL, 0);
}

static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);

static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
{
	struct pt_regs *regs = get_irq_regs();
	if (regs) {
		printk(KERN_INFO "CPU%d:\n", smp_processor_id());
		show_regs(regs);
	}
	schedule_work(&sysrq_showallcpus);
}

static struct sysrq_key_op sysrq_showallcpus_op = {
	.handler	= sysrq_handle_showallcpus,
	.help_msg	= "aLlcpus",
	.action_msg	= "Show backtrace of all active CPUs",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};
#endif

static void sysrq_handle_showregs(int key, struct tty_struct *tty)
{
	struct pt_regs *regs = get_irq_regs();
	if (regs)
		show_regs(regs);
	perf_counter_print_debug();
}
static struct sysrq_key_op sysrq_showregs_op = {
	.handler	= sysrq_handle_showregs,
	.help_msg	= "showPc",
	.action_msg	= "Show Regs",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};

static void sysrq_handle_showstate(int key, struct tty_struct *tty)
{
	show_state();
}
static struct sysrq_key_op sysrq_showstate_op = {
	.handler	= sysrq_handle_showstate,
	.help_msg	= "showTasks",
	.action_msg	= "Show State",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};

static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
{
	show_state_filter(TASK_UNINTERRUPTIBLE);
}
static struct sysrq_key_op sysrq_showstate_blocked_op = {
	.handler	= sysrq_handle_showstate_blocked,
	.help_msg	= "shoW-blocked-tasks",
	.action_msg	= "Show Blocked State",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};


static void sysrq_handle_showmem(int key, struct tty_struct *tty)
{
	show_mem();
}
static struct sysrq_key_op sysrq_showmem_op = {
	.handler	= sysrq_handle_showmem,
	.help_msg	= "showMem",
	.action_msg	= "Show Memory",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};

/*
 * Signal sysrq helper function.  Sends a signal to all user processes.
 */
static void send_sig_all(int sig)
{
	struct task_struct *p;

	for_each_process(p) {
		if (p->mm && !is_global_init(p))
			/* Not swapper, init nor kernel thread */
			force_sig(sig, p);
	}
}

static void sysrq_handle_term(int key, struct tty_struct *tty)
{
	send_sig_all(SIGTERM);
	console_loglevel = 8;
}
static struct sysrq_key_op sysrq_term_op = {
	.handler	= sysrq_handle_term,
	.help_msg	= "tErm",
	.action_msg	= "Terminate All Tasks",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};

static void moom_callback(struct work_struct *ignored)
{
	out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
}

static DECLARE_WORK(moom_work, moom_callback);

static void sysrq_handle_moom(int key, struct tty_struct *tty)
{
	schedule_work(&moom_work);
}
static struct sysrq_key_op sysrq_moom_op = {
	.handler	= sysrq_handle_moom,
	.help_msg	= "Full",
	.action_msg	= "Manual OOM execution",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};

static void sysrq_handle_kill(int key, struct tty_struct *tty)
{
	send_sig_all(SIGKILL);
	console_loglevel = 8;
}
static struct sysrq_key_op sysrq_kill_op = {
	.handler	= sysrq_handle_kill,
	.help_msg	= "kIll",
	.action_msg	= "Kill All Tasks",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};

static void sysrq_handle_unrt(int key, struct tty_struct *tty)
{
	normalize_rt_tasks();
}
static struct sysrq_key_op sysrq_unrt_op = {
	.handler	= sysrq_handle_unrt,
	.help_msg	= "Nice",
	.action_msg	= "Nice All RT Tasks",
	.enable_mask	= SYSRQ_ENABLE_RTNICE,
};

/* Key Operations table and lock */
static DEFINE_SPINLOCK(sysrq_key_table_lock);

static struct sysrq_key_op *sysrq_key_table[36] = {
	&sysrq_loglevel_op,		/* 0 */
	&sysrq_loglevel_op,		/* 1 */
	&sysrq_loglevel_op,		/* 2 */
	&sysrq_loglevel_op,		/* 3 */
	&sysrq_loglevel_op,		/* 4 */
	&sysrq_loglevel_op,		/* 5 */
	&sysrq_loglevel_op,		/* 6 */
	&sysrq_loglevel_op,		/* 7 */
	&sysrq_loglevel_op,		/* 8 */
	&sysrq_loglevel_op,		/* 9 */

	/*
	 * a: Don't use for system provided sysrqs, it is handled specially on
	 * sparc and will never arrive.
	 */
	NULL,				/* a */
	&sysrq_reboot_op,		/* b */
	&sysrq_crashdump_op,		/* c & ibm_emac driver debug */
	&sysrq_showlocks_op,		/* d */
	&sysrq_term_op,			/* e */
	&sysrq_moom_op,			/* f */
	/* g: May be registered by ppc for kgdb */
	NULL,				/* g */
	NULL,				/* h */
	&sysrq_kill_op,			/* i */
	NULL,				/* j */
	&sysrq_SAK_op,			/* k */
#ifdef CONFIG_SMP
	&sysrq_showallcpus_op,		/* l */
#else
	NULL,				/* l */
#endif
	&sysrq_showmem_op,		/* m */
	&sysrq_unrt_op,			/* n */
	/* o: This will often be registered as 'Off' at init time */
	NULL,				/* o */
	&sysrq_showregs_op,		/* p */
	&sysrq_show_timers_op,		/* q */
	&sysrq_unraw_op,		/* r */
	&sysrq_sync_op,			/* s */
	&sysrq_showstate_op,		/* t */
	&sysrq_mountro_op,		/* u */
	/* v: May be registered at init time by SMP VOYAGER */
	NULL,				/* v */
	&sysrq_showstate_blocked_op,	/* w */
	/* x: May be registered on ppc/powerpc for xmon */
	NULL,				/* x */
	/* y: May be registered on sparc64 for global register dump */
	NULL,				/* y */
	NULL				/* z */
};

/* key2index calculation, -1 on invalid index */
static int sysrq_key_table_key2index(int key)
{
	int retval;

	if ((key >= '0') && (key <= '9'))
		retval = key - '0';
	else if ((key >= 'a') && (key <= 'z'))
		retval = key + 10 - 'a';
	else
		retval = -1;
	return retval;
}

/*
 * get and put functions for the table, exposed to modules.
 */
struct sysrq_key_op *__sysrq_get_key_op(int key)
{
        struct sysrq_key_op *op_p = NULL;
        int i;

	i = sysrq_key_table_key2index(key);
	if (i != -1)
	        op_p = sysrq_key_table[i];
        return op_p;
}

static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
{
        int i = sysrq_key_table_key2index(key);

        if (i != -1)
                sysrq_key_table[i] = op_p;
}

/*
 * This is the non-locking version of handle_sysrq.  It must/can only be called
 * by sysrq key handlers, as they are inside of the lock
 */
void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
{
	struct sysrq_key_op *op_p;
	int orig_log_level;
	int i;
	unsigned long flags;

	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	orig_log_level = console_loglevel;
	console_loglevel = 7;
	printk(KERN_INFO "SysRq : ");

        op_p = __sysrq_get_key_op(key);
        if (op_p) {
		/*
		 * Should we check for enabled operations (/proc/sysrq-trigger
		 * should not) and is the invoked operation enabled?
		 */
		if (!check_mask || sysrq_on_mask(op_p->enable_mask)) {
			printk("%s\n", op_p->action_msg);
			console_loglevel = orig_log_level;
			op_p->handler(key, tty);
		} else {
			printk("This sysrq operation is disabled.\n");
		}
	} else {
		printk("HELP : ");
		/* Only print the help msg once per handler */
		for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
			if (sysrq_key_table[i]) {
				int j;

				for (j = 0; sysrq_key_table[i] !=
						sysrq_key_table[j]; j++)
					;
				if (j != i)
					continue;
				printk("%s ", sysrq_key_table[i]->help_msg);
			}
		}
		printk("\n");
		console_loglevel = orig_log_level;
	}
	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
}

/*
 * This function is called by the keyboard handler when SysRq is pressed
 * and any other keycode arrives.
 */
void handle_sysrq(int key, struct tty_struct *tty)
{
	if (sysrq_on())
		__handle_sysrq(key, tty, 1);
}
EXPORT_SYMBOL(handle_sysrq);

static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
                                struct sysrq_key_op *remove_op_p)
{

	int retval;
	unsigned long flags;

	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	if (__sysrq_get_key_op(key) == remove_op_p) {
		__sysrq_put_key_op(key, insert_op_p);
		retval = 0;
	} else {
		retval = -1;
	}
	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	return retval;
}

int register_sysrq_key(int key, struct sysrq_key_op *op_p)
{
	return __sysrq_swap_key_ops(key, op_p, NULL);
}
EXPORT_SYMBOL(register_sysrq_key);

int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
{
	return __sysrq_swap_key_ops(key, NULL, op_p);
}
EXPORT_SYMBOL(unregister_sysrq_key);

#ifdef CONFIG_PROC_FS
/*
 * writing 'C' to /proc/sysrq-trigger is like sysrq-C
 */
static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
				   size_t count, loff_t *ppos)
{
	if (count) {
		char c;

		if (get_user(c, buf))
			return -EFAULT;
		__handle_sysrq(c, NULL, 0);
	}
	return count;
}

static const struct file_operations proc_sysrq_trigger_operations = {
	.write		= write_sysrq_trigger,
};

static int __init sysrq_init(void)
{
	proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
	return 0;
}
module_init(sysrq_init);
#endif
Commit	Line	Data
1da177e4 LT	1	/* -- linux-c --
	2	*
	3	* $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
	4	*
	5	* Linux Magic System Request Key Hacks
	6	*
	7	* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
	8	* based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
	9	*
	10	* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
	11	* overhauled to use key registration
	12	* based upon discusions in irc://irc.openprojects.net/#kernelnewbies
	13	*/
	14
1da177e4 LT	15	#include <linux/sched.h>
	16	#include <linux/interrupt.h>
	17	#include <linux/mm.h>
	18	#include <linux/fs.h>
	19	#include <linux/tty.h>
	20	#include <linux/mount.h>
	21	#include <linux/kdev_t.h>
	22	#include <linux/major.h>
	23	#include <linux/reboot.h>
	24	#include <linux/sysrq.h>
	25	#include <linux/kbd_kern.h>
f40cbaa5	26	#include <linux/proc_fs.h>
1da177e4	27	#include <linux/quotaops.h>
0793a61d	28	#include <linux/perf_counter.h>
1da177e4 LT	29	#include <linux/kernel.h>
	30	#include <linux/module.h>
	31	#include <linux/suspend.h>
	32	#include <linux/writeback.h>
	33	#include <linux/buffer_head.h> /* for fsync_bdev() */
	34	#include <linux/swap.h>
	35	#include <linux/spinlock.h>
	36	#include <linux/vt_kern.h>
	37	#include <linux/workqueue.h>
86b1ae38	38	#include <linux/kexec.h>
7d12e780	39	#include <linux/irq.h>
88ad0bf6	40	#include <linux/hrtimer.h>
5a3135c2	41	#include <linux/oom.h>
1da177e4 LT	42
1da177e4 LT	43	#include <asm/ptrace.h>
2033b0c3	44	#include <asm/irq_regs.h>
1da177e4 LT	45
1da177e4 LT	46	/* Whether we react on sysrq keys or just ignore them */
5d6f647f IM	47	int __read_mostly __sysrq_enabled = 1;
	48
	49	static int __read_mostly sysrq_always_enabled;
	50
	51	int sysrq_on(void)
	52	{
	53	return __sysrq_enabled \|\| sysrq_always_enabled;
	54	}
	55
	56	/*
	57	* A value of 1 means 'all', other nonzero values are an op mask:
	58	*/
	59	static inline int sysrq_on_mask(int mask)
	60	{
	61	return sysrq_always_enabled \|\| __sysrq_enabled == 1 \|\|
	62	(__sysrq_enabled & mask);
	63	}
	64
	65	static int __init sysrq_always_enabled_setup(char *str)
	66	{
	67	sysrq_always_enabled = 1;
	68	printk(KERN_INFO "debug: sysrq always enabled.\n");
	69
	70	return 1;
	71	}
	72
	73	__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
	74
1da177e4	75
7d12e780	76	static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
1da177e4 LT	77	{
	78	int i;
	79	i = key - '0';
	80	console_loglevel = 7;
	81	printk("Loglevel set to %d\n", i);
	82	console_loglevel = i;
bf36b901	83	}
1da177e4 LT	84	static struct sysrq_key_op sysrq_loglevel_op = {
	85	.handler = sysrq_handle_loglevel,
	86	.help_msg = "loglevel0-8",
	87	.action_msg = "Changing Loglevel",
	88	.enable_mask = SYSRQ_ENABLE_LOG,
	89	};
	90
1da177e4	91	#ifdef CONFIG_VT
7d12e780	92	static void sysrq_handle_SAK(int key, struct tty_struct *tty)
1da177e4	93	{
8b6312f4	94	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
8b6312f4	95	schedule_work(SAK_work);
1da177e4 LT	96	}
	97	static struct sysrq_key_op sysrq_SAK_op = {
	98	.handler = sysrq_handle_SAK,
	99	.help_msg = "saK",
	100	.action_msg = "SAK",
	101	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	102	};
bf36b901 AM	103	#else
bf36b901 AM	104	#define sysrq_SAK_op ((struct sysrq_key_op )0)
1da177e4 LT	105	#endif
	106
	107	#ifdef CONFIG_VT
7d12e780	108	static void sysrq_handle_unraw(int key, struct tty_struct *tty)
1da177e4 LT	109	{
	110	struct kbd_struct *kbd = &kbd_table[fg_console];
	111
	112	if (kbd)
2e8ecb9d	113	kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
1da177e4 LT	114	}
	115	static struct sysrq_key_op sysrq_unraw_op = {
	116	.handler = sysrq_handle_unraw,
	117	.help_msg = "unRaw",
2e8ecb9d	118	.action_msg = "Keyboard mode set to system default",
1da177e4 LT	119	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
1da177e4 LT	120	};
bf36b901 AM	121	#else
bf36b901 AM	122	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	123	#endif /* CONFIG_VT */
1da177e4 LT	124
86b1ae38	125	#ifdef CONFIG_KEXEC
7d12e780	126	static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
86b1ae38	127	{
7d12e780	128	crash_kexec(get_irq_regs());
86b1ae38 HN	129	}
	130	static struct sysrq_key_op sysrq_crashdump_op = {
	131	.handler = sysrq_handle_crashdump,
	132	.help_msg = "Crashdump",
	133	.action_msg = "Trigger a crashdump",
	134	.enable_mask = SYSRQ_ENABLE_DUMP,
	135	};
bf36b901 AM	136	#else
bf36b901 AM	137	#define sysrq_crashdump_op ((struct sysrq_key_op )0)
86b1ae38 HN	138	#endif
86b1ae38 HN	139
7d12e780	140	static void sysrq_handle_reboot(int key, struct tty_struct *tty)
1da177e4	141	{
b2e9c7d0	142	lockdep_off();
1da177e4	143	local_irq_enable();
4de8b9b7	144	emergency_restart();
1da177e4	145	}
1da177e4 LT	146	static struct sysrq_key_op sysrq_reboot_op = {
	147	.handler = sysrq_handle_reboot,
	148	.help_msg = "reBoot",
	149	.action_msg = "Resetting",
	150	.enable_mask = SYSRQ_ENABLE_BOOT,
	151	};
	152
7d12e780	153	static void sysrq_handle_sync(int key, struct tty_struct *tty)
1da177e4 LT	154	{
	155	emergency_sync();
	156	}
1da177e4 LT	157	static struct sysrq_key_op sysrq_sync_op = {
	158	.handler = sysrq_handle_sync,
	159	.help_msg = "Sync",
	160	.action_msg = "Emergency Sync",
	161	.enable_mask = SYSRQ_ENABLE_SYNC,
	162	};
	163
88ad0bf6 IM	164	static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
	165	{
	166	sysrq_timer_list_show();
	167	}
	168
	169	static struct sysrq_key_op sysrq_show_timers_op = {
	170	.handler = sysrq_handle_show_timers,
	171	.help_msg = "show-all-timers(Q)",
322acf65	172	.action_msg = "Show clockevent devices & pending hrtimers (no others)",
88ad0bf6 IM	173	};
88ad0bf6 IM	174
7d12e780	175	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	176	{
	177	emergency_remount();
	178	}
1da177e4 LT	179	static struct sysrq_key_op sysrq_mountro_op = {
	180	.handler = sysrq_handle_mountro,
	181	.help_msg = "Unmount",
	182	.action_msg = "Emergency Remount R/O",
	183	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	184	};
	185
8c64580d	186	#ifdef CONFIG_LOCKDEP
7d12e780	187	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	188	{
9a11b49a	189	debug_show_all_locks();
de5097c2	190	}
8c64580d	191
de5097c2 IM	192	static struct sysrq_key_op sysrq_showlocks_op = {
	193	.handler = sysrq_handle_showlocks,
	194	.help_msg = "show-all-locks(D)",
	195	.action_msg = "Show Locks Held",
	196	};
bf36b901 AM	197	#else
bf36b901 AM	198	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	199	#endif
1da177e4	200
5045bcae RR	201	#ifdef CONFIG_SMP
	202	static DEFINE_SPINLOCK(show_lock);
	203
	204	static void showacpu(void *dummy)
	205	{
	206	unsigned long flags;
	207
	208	/* Idle CPUs have no interesting backtrace. */
	209	if (idle_cpu(smp_processor_id()))
	210	return;
	211
	212	spin_lock_irqsave(&show_lock, flags);
	213	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	214	show_stack(NULL, NULL);
	215	spin_unlock_irqrestore(&show_lock, flags);
	216	}
	217
	218	static void sysrq_showregs_othercpus(struct work_struct *dummy)
	219	{
8b604d52	220	smp_call_function(showacpu, NULL, 0);
5045bcae RR	221	}
	222
	223	static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
	224
	225	static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
	226	{
	227	struct pt_regs *regs = get_irq_regs();
	228	if (regs) {
	229	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	230	show_regs(regs);
	231	}
	232	schedule_work(&sysrq_showallcpus);
	233	}
	234
	235	static struct sysrq_key_op sysrq_showallcpus_op = {
	236	.handler = sysrq_handle_showallcpus,
	237	.help_msg = "aLlcpus",
	238	.action_msg = "Show backtrace of all active CPUs",
	239	.enable_mask = SYSRQ_ENABLE_DUMP,
	240	};
	241	#endif
	242
7d12e780	243	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	244	{
7d12e780 DH	245	struct pt_regs *regs = get_irq_regs();
	246	if (regs)
	247	show_regs(regs);
0793a61d	248	perf_counter_print_debug();
1da177e4 LT	249	}
	250	static struct sysrq_key_op sysrq_showregs_op = {
	251	.handler = sysrq_handle_showregs,
	252	.help_msg = "showPc",
	253	.action_msg = "Show Regs",
	254	.enable_mask = SYSRQ_ENABLE_DUMP,
	255	};
	256
7d12e780	257	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	258	{
	259	show_state();
	260	}
	261	static struct sysrq_key_op sysrq_showstate_op = {
	262	.handler = sysrq_handle_showstate,
	263	.help_msg = "showTasks",
	264	.action_msg = "Show State",
	265	.enable_mask = SYSRQ_ENABLE_DUMP,
	266	};
	267
e59e2ae2 IM	268	static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
	269	{
	270	show_state_filter(TASK_UNINTERRUPTIBLE);
	271	}
	272	static struct sysrq_key_op sysrq_showstate_blocked_op = {
	273	.handler = sysrq_handle_showstate_blocked,
d346cce3	274	.help_msg = "shoW-blocked-tasks",
e59e2ae2 IM	275	.action_msg = "Show Blocked State",
	276	.enable_mask = SYSRQ_ENABLE_DUMP,
	277	};
	278
	279
7d12e780	280	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	281	{
	282	show_mem();
	283	}
	284	static struct sysrq_key_op sysrq_showmem_op = {
	285	.handler = sysrq_handle_showmem,
	286	.help_msg = "showMem",
	287	.action_msg = "Show Memory",
	288	.enable_mask = SYSRQ_ENABLE_DUMP,
	289	};
	290
bf36b901 AM	291	/*
	292	* Signal sysrq helper function. Sends a signal to all user processes.
	293	*/
1da177e4 LT	294	static void send_sig_all(int sig)
	295	{
	296	struct task_struct *p;
	297
	298	for_each_process(p) {
b460cbc5	299	if (p->mm && !is_global_init(p))
1da177e4 LT	300	/* Not swapper, init nor kernel thread */
	301	force_sig(sig, p);
	302	}
	303	}
	304
7d12e780	305	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	306	{
	307	send_sig_all(SIGTERM);
	308	console_loglevel = 8;
	309	}
	310	static struct sysrq_key_op sysrq_term_op = {
	311	.handler = sysrq_handle_term,
	312	.help_msg = "tErm",
	313	.action_msg = "Terminate All Tasks",
	314	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	315	};
	316
65f27f38	317	static void moom_callback(struct work_struct *ignored)
1da177e4	318	{
0e88460d	319	out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
1da177e4 LT	320	}
1da177e4 LT	321
65f27f38	322	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	323
7d12e780	324	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	325	{
	326	schedule_work(&moom_work);
	327	}
	328	static struct sysrq_key_op sysrq_moom_op = {
	329	.handler = sysrq_handle_moom,
	330	.help_msg = "Full",
	331	.action_msg = "Manual OOM execution",
b4236f81	332	.enable_mask = SYSRQ_ENABLE_SIGNAL,
1da177e4 LT	333	};
1da177e4 LT	334
7d12e780	335	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	336	{
	337	send_sig_all(SIGKILL);
	338	console_loglevel = 8;
	339	}
	340	static struct sysrq_key_op sysrq_kill_op = {
	341	.handler = sysrq_handle_kill,
	342	.help_msg = "kIll",
	343	.action_msg = "Kill All Tasks",
	344	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	345	};
	346
7d12e780	347	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	348	{
	349	normalize_rt_tasks();
	350	}
	351	static struct sysrq_key_op sysrq_unrt_op = {
	352	.handler = sysrq_handle_unrt,
	353	.help_msg = "Nice",
	354	.action_msg = "Nice All RT Tasks",
	355	.enable_mask = SYSRQ_ENABLE_RTNICE,
	356	};
	357
	358	/* Key Operations table and lock */
	359	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	360
	361	static struct sysrq_key_op *sysrq_key_table[36] = {
	362	&sysrq_loglevel_op, /* 0 */
	363	&sysrq_loglevel_op, /* 1 */
	364	&sysrq_loglevel_op, /* 2 */
	365	&sysrq_loglevel_op, /* 3 */
	366	&sysrq_loglevel_op, /* 4 */
	367	&sysrq_loglevel_op, /* 5 */
	368	&sysrq_loglevel_op, /* 6 */
	369	&sysrq_loglevel_op, /* 7 */
	370	&sysrq_loglevel_op, /* 8 */
	371	&sysrq_loglevel_op, /* 9 */
	372
	373	/*
d346cce3 RD	374	* a: Don't use for system provided sysrqs, it is handled specially on
d346cce3 RD	375	* sparc and will never arrive.
bf36b901 AM	376	*/
	377	NULL, /* a */
	378	&sysrq_reboot_op, /* b */
d346cce3	379	&sysrq_crashdump_op, /* c & ibm_emac driver debug */
bf36b901 AM	380	&sysrq_showlocks_op, /* d */
	381	&sysrq_term_op, /* e */
	382	&sysrq_moom_op, /* f */
d346cce3	383	/* g: May be registered by ppc for kgdb */
bf36b901 AM	384	NULL, /* g */
	385	NULL, /* h */
	386	&sysrq_kill_op, /* i */
	387	NULL, /* j */
	388	&sysrq_SAK_op, /* k */
5045bcae RR	389	#ifdef CONFIG_SMP
	390	&sysrq_showallcpus_op, /* l */
	391	#else
bf36b901	392	NULL, /* l */
5045bcae	393	#endif
bf36b901 AM	394	&sysrq_showmem_op, /* m */
bf36b901 AM	395	&sysrq_unrt_op, /* n */
d346cce3	396	/* o: This will often be registered as 'Off' at init time */
bf36b901 AM	397	NULL, /* o */
bf36b901 AM	398	&sysrq_showregs_op, /* p */
88ad0bf6	399	&sysrq_show_timers_op, /* q */
d346cce3	400	&sysrq_unraw_op, /* r */
bf36b901 AM	401	&sysrq_sync_op, /* s */
	402	&sysrq_showstate_op, /* t */
	403	&sysrq_mountro_op, /* u */
d346cce3	404	/* v: May be registered at init time by SMP VOYAGER */
bf36b901	405	NULL, /* v */
d346cce3 RD	406	&sysrq_showstate_blocked_op, /* w */
	407	/* x: May be registered on ppc/powerpc for xmon */
	408	NULL, /* x */
93dae5b7	409	/* y: May be registered on sparc64 for global register dump */
bf36b901 AM	410	NULL, /* y */
bf36b901 AM	411	NULL /* z */
1da177e4 LT	412	};
	413
	414	/* key2index calculation, -1 on invalid index */
bf36b901 AM	415	static int sysrq_key_table_key2index(int key)
bf36b901 AM	416	{
1da177e4	417	int retval;
bf36b901 AM	418
bf36b901 AM	419	if ((key >= '0') && (key <= '9'))
1da177e4	420	retval = key - '0';
bf36b901	421	else if ((key >= 'a') && (key <= 'z'))
1da177e4	422	retval = key + 10 - 'a';
bf36b901	423	else
1da177e4	424	retval = -1;
1da177e4 LT	425	return retval;
	426	}
	427
	428	/*
	429	* get and put functions for the table, exposed to modules.
	430	*/
bf36b901 AM	431	struct sysrq_key_op *__sysrq_get_key_op(int key)
	432	{
	433	struct sysrq_key_op *op_p = NULL;
1da177e4	434	int i;
bf36b901	435
1da177e4	436	i = sysrq_key_table_key2index(key);
bf36b901 AM	437	if (i != -1)
bf36b901 AM	438	op_p = sysrq_key_table[i];
1da177e4 LT	439	return op_p;
	440	}
	441
bf36b901 AM	442	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	443	{
	444	int i = sysrq_key_table_key2index(key);
1da177e4	445
1da177e4 LT	446	if (i != -1)
	447	sysrq_key_table[i] = op_p;
	448	}
	449
	450	/*
bf36b901 AM	451	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	452	* by sysrq key handlers, as they are inside of the lock
1da177e4	453	*/
7d12e780	454	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	455	{
	456	struct sysrq_key_op *op_p;
	457	int orig_log_level;
bf36b901	458	int i;
1da177e4 LT	459	unsigned long flags;
	460
	461	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	462	orig_log_level = console_loglevel;
	463	console_loglevel = 7;
	464	printk(KERN_INFO "SysRq : ");
	465
	466	op_p = __sysrq_get_key_op(key);
	467	if (op_p) {
bf36b901 AM	468	/*
	469	* Should we check for enabled operations (/proc/sysrq-trigger
	470	* should not) and is the invoked operation enabled?
	471	*/
5d6f647f	472	if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
bf36b901	473	printk("%s\n", op_p->action_msg);
1da177e4	474	console_loglevel = orig_log_level;
7d12e780	475	op_p->handler(key, tty);
bf36b901	476	} else {
1da177e4	477	printk("This sysrq operation is disabled.\n");
bf36b901	478	}
1da177e4 LT	479	} else {
	480	printk("HELP : ");
	481	/* Only print the help msg once per handler */
bf36b901 AM	482	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	483	if (sysrq_key_table[i]) {
	484	int j;
	485
	486	for (j = 0; sysrq_key_table[i] !=
	487	sysrq_key_table[j]; j++)
	488	;
	489	if (j != i)
	490	continue;
	491	printk("%s ", sysrq_key_table[i]->help_msg);
	492	}
1da177e4	493	}
bf36b901	494	printk("\n");
1da177e4 LT	495	console_loglevel = orig_log_level;
	496	}
	497	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	498	}
	499
	500	/*
	501	* This function is called by the keyboard handler when SysRq is pressed
	502	* and any other keycode arrives.
	503	*/
7d12e780	504	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4	505	{
5d6f647f IM	506	if (sysrq_on())
5d6f647f IM	507	__handle_sysrq(key, tty, 1);
1da177e4	508	}
bf36b901	509	EXPORT_SYMBOL(handle_sysrq);
1da177e4	510
cf62ddce	511	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	512	struct sysrq_key_op *remove_op_p)
bf36b901 AM	513	{
1da177e4 LT	514
	515	int retval;
	516	unsigned long flags;
	517
	518	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	519	if (__sysrq_get_key_op(key) == remove_op_p) {
	520	__sysrq_put_key_op(key, insert_op_p);
	521	retval = 0;
	522	} else {
	523	retval = -1;
	524	}
	525	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	526	return retval;
	527	}
	528
	529	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	530	{
	531	return __sysrq_swap_key_ops(key, op_p, NULL);
	532	}
bf36b901	533	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	534
	535	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	536	{
	537	return __sysrq_swap_key_ops(key, NULL, op_p);
	538	}
1da177e4	539	EXPORT_SYMBOL(unregister_sysrq_key);
f40cbaa5 AD	540
	541	#ifdef CONFIG_PROC_FS
	542	/*
	543	* writing 'C' to /proc/sysrq-trigger is like sysrq-C
	544	*/
	545	static ssize_t write_sysrq_trigger(struct file file, const char __user buf,
	546	size_t count, loff_t *ppos)
	547	{
	548	if (count) {
	549	char c;
	550
	551	if (get_user(c, buf))
	552	return -EFAULT;
	553	__handle_sysrq(c, NULL, 0);
	554	}
	555	return count;
	556	}
	557
	558	static const struct file_operations proc_sysrq_trigger_operations = {
	559	.write = write_sysrq_trigger,
	560	};
	561
	562	static int __init sysrq_init(void)
	563	{
	564	proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
	565	return 0;
	566	}
	567	module_init(sysrq_init);
	568	#endif