[deliverable/linux.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/quotaops.h>
#include <linux/smp_lock.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 <asm/ptrace.h>
#include <asm/irq_regs.h>

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

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)
{
	if (tty)
		do_SAK(tty);
	reset_vc(vc_cons[fg_console].d);
}
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 = VC_XLATE;
}
static struct sysrq_key_op sysrq_unraw_op = {
	.handler	= sysrq_handle_unraw,
	.help_msg	= "unRaw",
	.action_msg	= "Keyboard mode set to XLATE",
	.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_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

static void sysrq_handle_showregs(int key, struct tty_struct *tty)
{
	struct pt_regs *regs = get_irq_regs();
	if (regs)
		show_regs(regs);
}
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_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_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_DATA(0)->node_zonelists[ZONE_NORMAL],
			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",
};

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 */

	/*
	 * 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 */
	&sysrq_showlocks_op,		/* d */
	&sysrq_term_op,			/* e */
	&sysrq_moom_op,			/* f */
	NULL,				/* g */
	NULL,				/* h */
	&sysrq_kill_op,			/* i */
	NULL,				/* j */
	&sysrq_SAK_op,			/* k */
	NULL,				/* l */
	&sysrq_showmem_op,		/* m */
	&sysrq_unrt_op,			/* n */
	/* This will often be registered as 'Off' at init time */
	NULL,				/* o */
	&sysrq_showregs_op,		/* p */
	NULL,				/* q */
	&sysrq_unraw_op,			/* r */
	&sysrq_sync_op,			/* s */
	&sysrq_showstate_op,		/* t */
	&sysrq_mountro_op,		/* u */
	/* May be assigned at init time by SMP VOYAGER */
	NULL,				/* v */
	NULL,				/* w */
	NULL,				/* x */
	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_enabled == 1 ||
		    (sysrq_enabled & 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_enabled)
		return;
	__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);
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>
	26	#include <linux/quotaops.h>
	27	#include <linux/smp_lock.h>
	28	#include <linux/kernel.h>
	29	#include <linux/module.h>
	30	#include <linux/suspend.h>
	31	#include <linux/writeback.h>
	32	#include <linux/buffer_head.h> /* for fsync_bdev() */
	33	#include <linux/swap.h>
	34	#include <linux/spinlock.h>
	35	#include <linux/vt_kern.h>
	36	#include <linux/workqueue.h>
86b1ae38	37	#include <linux/kexec.h>
7d12e780	38	#include <linux/irq.h>
1da177e4 LT	39
1da177e4 LT	40	#include <asm/ptrace.h>
2033b0c3	41	#include <asm/irq_regs.h>
1da177e4 LT	42
	43	/* Whether we react on sysrq keys or just ignore them */
	44	int sysrq_enabled = 1;
	45
7d12e780	46	static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
1da177e4 LT	47	{
	48	int i;
	49	i = key - '0';
	50	console_loglevel = 7;
	51	printk("Loglevel set to %d\n", i);
	52	console_loglevel = i;
bf36b901	53	}
1da177e4 LT	54	static struct sysrq_key_op sysrq_loglevel_op = {
	55	.handler = sysrq_handle_loglevel,
	56	.help_msg = "loglevel0-8",
	57	.action_msg = "Changing Loglevel",
	58	.enable_mask = SYSRQ_ENABLE_LOG,
	59	};
	60
1da177e4	61	#ifdef CONFIG_VT
7d12e780	62	static void sysrq_handle_SAK(int key, struct tty_struct *tty)
1da177e4 LT	63	{
	64	if (tty)
	65	do_SAK(tty);
	66	reset_vc(vc_cons[fg_console].d);
	67	}
	68	static struct sysrq_key_op sysrq_SAK_op = {
	69	.handler = sysrq_handle_SAK,
	70	.help_msg = "saK",
	71	.action_msg = "SAK",
	72	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	73	};
bf36b901 AM	74	#else
bf36b901 AM	75	#define sysrq_SAK_op ((struct sysrq_key_op )0)
1da177e4 LT	76	#endif
	77
	78	#ifdef CONFIG_VT
7d12e780	79	static void sysrq_handle_unraw(int key, struct tty_struct *tty)
1da177e4 LT	80	{
	81	struct kbd_struct *kbd = &kbd_table[fg_console];
	82
	83	if (kbd)
	84	kbd->kbdmode = VC_XLATE;
	85	}
	86	static struct sysrq_key_op sysrq_unraw_op = {
	87	.handler = sysrq_handle_unraw,
	88	.help_msg = "unRaw",
	89	.action_msg = "Keyboard mode set to XLATE",
	90	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	91	};
bf36b901 AM	92	#else
bf36b901 AM	93	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	94	#endif /* CONFIG_VT */
1da177e4 LT	95
86b1ae38	96	#ifdef CONFIG_KEXEC
7d12e780	97	static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
86b1ae38	98	{
7d12e780	99	crash_kexec(get_irq_regs());
86b1ae38 HN	100	}
	101	static struct sysrq_key_op sysrq_crashdump_op = {
	102	.handler = sysrq_handle_crashdump,
	103	.help_msg = "Crashdump",
	104	.action_msg = "Trigger a crashdump",
	105	.enable_mask = SYSRQ_ENABLE_DUMP,
	106	};
bf36b901 AM	107	#else
bf36b901 AM	108	#define sysrq_crashdump_op ((struct sysrq_key_op )0)
86b1ae38 HN	109	#endif
86b1ae38 HN	110
7d12e780	111	static void sysrq_handle_reboot(int key, struct tty_struct *tty)
1da177e4	112	{
b2e9c7d0	113	lockdep_off();
1da177e4	114	local_irq_enable();
4de8b9b7	115	emergency_restart();
1da177e4	116	}
1da177e4 LT	117	static struct sysrq_key_op sysrq_reboot_op = {
	118	.handler = sysrq_handle_reboot,
	119	.help_msg = "reBoot",
	120	.action_msg = "Resetting",
	121	.enable_mask = SYSRQ_ENABLE_BOOT,
	122	};
	123
7d12e780	124	static void sysrq_handle_sync(int key, struct tty_struct *tty)
1da177e4 LT	125	{
	126	emergency_sync();
	127	}
1da177e4 LT	128	static struct sysrq_key_op sysrq_sync_op = {
	129	.handler = sysrq_handle_sync,
	130	.help_msg = "Sync",
	131	.action_msg = "Emergency Sync",
	132	.enable_mask = SYSRQ_ENABLE_SYNC,
	133	};
	134
7d12e780	135	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	136	{
	137	emergency_remount();
	138	}
1da177e4 LT	139	static struct sysrq_key_op sysrq_mountro_op = {
	140	.handler = sysrq_handle_mountro,
	141	.help_msg = "Unmount",
	142	.action_msg = "Emergency Remount R/O",
	143	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	144	};
	145
8c64580d	146	#ifdef CONFIG_LOCKDEP
7d12e780	147	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	148	{
9a11b49a	149	debug_show_all_locks();
de5097c2	150	}
8c64580d	151
de5097c2 IM	152	static struct sysrq_key_op sysrq_showlocks_op = {
	153	.handler = sysrq_handle_showlocks,
	154	.help_msg = "show-all-locks(D)",
	155	.action_msg = "Show Locks Held",
	156	};
bf36b901 AM	157	#else
bf36b901 AM	158	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	159	#endif
1da177e4	160
7d12e780	161	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	162	{
7d12e780 DH	163	struct pt_regs *regs = get_irq_regs();
	164	if (regs)
	165	show_regs(regs);
1da177e4 LT	166	}
	167	static struct sysrq_key_op sysrq_showregs_op = {
	168	.handler = sysrq_handle_showregs,
	169	.help_msg = "showPc",
	170	.action_msg = "Show Regs",
	171	.enable_mask = SYSRQ_ENABLE_DUMP,
	172	};
	173
7d12e780	174	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	175	{
	176	show_state();
	177	}
	178	static struct sysrq_key_op sysrq_showstate_op = {
	179	.handler = sysrq_handle_showstate,
	180	.help_msg = "showTasks",
	181	.action_msg = "Show State",
	182	.enable_mask = SYSRQ_ENABLE_DUMP,
	183	};
	184
7d12e780	185	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	186	{
	187	show_mem();
	188	}
	189	static struct sysrq_key_op sysrq_showmem_op = {
	190	.handler = sysrq_handle_showmem,
	191	.help_msg = "showMem",
	192	.action_msg = "Show Memory",
	193	.enable_mask = SYSRQ_ENABLE_DUMP,
	194	};
	195
bf36b901 AM	196	/*
	197	* Signal sysrq helper function. Sends a signal to all user processes.
	198	*/
1da177e4 LT	199	static void send_sig_all(int sig)
	200	{
	201	struct task_struct *p;
	202
	203	for_each_process(p) {
f400e198	204	if (p->mm && !is_init(p))
1da177e4 LT	205	/* Not swapper, init nor kernel thread */
	206	force_sig(sig, p);
	207	}
	208	}
	209
7d12e780	210	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	211	{
	212	send_sig_all(SIGTERM);
	213	console_loglevel = 8;
	214	}
	215	static struct sysrq_key_op sysrq_term_op = {
	216	.handler = sysrq_handle_term,
	217	.help_msg = "tErm",
	218	.action_msg = "Terminate All Tasks",
	219	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	220	};
	221
65f27f38	222	static void moom_callback(struct work_struct *ignored)
1da177e4	223	{
bf36b901 AM	224	out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
bf36b901 AM	225	GFP_KERNEL, 0);
1da177e4 LT	226	}
1da177e4 LT	227
65f27f38	228	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	229
7d12e780	230	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	231	{
	232	schedule_work(&moom_work);
	233	}
	234	static struct sysrq_key_op sysrq_moom_op = {
	235	.handler = sysrq_handle_moom,
	236	.help_msg = "Full",
	237	.action_msg = "Manual OOM execution",
	238	};
	239
7d12e780	240	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	241	{
	242	send_sig_all(SIGKILL);
	243	console_loglevel = 8;
	244	}
	245	static struct sysrq_key_op sysrq_kill_op = {
	246	.handler = sysrq_handle_kill,
	247	.help_msg = "kIll",
	248	.action_msg = "Kill All Tasks",
	249	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	250	};
	251
7d12e780	252	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	253	{
	254	normalize_rt_tasks();
	255	}
	256	static struct sysrq_key_op sysrq_unrt_op = {
	257	.handler = sysrq_handle_unrt,
	258	.help_msg = "Nice",
	259	.action_msg = "Nice All RT Tasks",
	260	.enable_mask = SYSRQ_ENABLE_RTNICE,
	261	};
	262
	263	/* Key Operations table and lock */
	264	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	265
	266	static struct sysrq_key_op *sysrq_key_table[36] = {
	267	&sysrq_loglevel_op, /* 0 */
	268	&sysrq_loglevel_op, /* 1 */
	269	&sysrq_loglevel_op, /* 2 */
	270	&sysrq_loglevel_op, /* 3 */
	271	&sysrq_loglevel_op, /* 4 */
	272	&sysrq_loglevel_op, /* 5 */
	273	&sysrq_loglevel_op, /* 6 */
	274	&sysrq_loglevel_op, /* 7 */
	275	&sysrq_loglevel_op, /* 8 */
	276	&sysrq_loglevel_op, /* 9 */
	277
	278	/*
	279	* Don't use for system provided sysrqs, it is handled specially on
	280	* sparc and will never arrive
	281	*/
	282	NULL, /* a */
	283	&sysrq_reboot_op, /* b */
	284	&sysrq_crashdump_op, /* c */
	285	&sysrq_showlocks_op, /* d */
	286	&sysrq_term_op, /* e */
	287	&sysrq_moom_op, /* f */
	288	NULL, /* g */
	289	NULL, /* h */
	290	&sysrq_kill_op, /* i */
	291	NULL, /* j */
	292	&sysrq_SAK_op, /* k */
	293	NULL, /* l */
	294	&sysrq_showmem_op, /* m */
	295	&sysrq_unrt_op, /* n */
	296	/* This will often be registered as 'Off' at init time */
	297	NULL, /* o */
	298	&sysrq_showregs_op, /* p */
	299	NULL, /* q */
	300	&sysrq_unraw_op, /* r */
	301	&sysrq_sync_op, /* s */
	302	&sysrq_showstate_op, /* t */
	303	&sysrq_mountro_op, /* u */
	304	/* May be assigned at init time by SMP VOYAGER */
	305	NULL, /* v */
	306	NULL, /* w */
	307	NULL, /* x */
	308	NULL, /* y */
	309	NULL /* z */
1da177e4 LT	310	};
	311
	312	/* key2index calculation, -1 on invalid index */
bf36b901 AM	313	static int sysrq_key_table_key2index(int key)
bf36b901 AM	314	{
1da177e4	315	int retval;
bf36b901 AM	316
bf36b901 AM	317	if ((key >= '0') && (key <= '9'))
1da177e4	318	retval = key - '0';
bf36b901	319	else if ((key >= 'a') && (key <= 'z'))
1da177e4	320	retval = key + 10 - 'a';
bf36b901	321	else
1da177e4	322	retval = -1;
1da177e4 LT	323	return retval;
	324	}
	325
	326	/*
	327	* get and put functions for the table, exposed to modules.
	328	*/
bf36b901 AM	329	struct sysrq_key_op *__sysrq_get_key_op(int key)
	330	{
	331	struct sysrq_key_op *op_p = NULL;
1da177e4	332	int i;
bf36b901	333
1da177e4	334	i = sysrq_key_table_key2index(key);
bf36b901 AM	335	if (i != -1)
bf36b901 AM	336	op_p = sysrq_key_table[i];
1da177e4 LT	337	return op_p;
	338	}
	339
bf36b901 AM	340	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	341	{
	342	int i = sysrq_key_table_key2index(key);
1da177e4	343
1da177e4 LT	344	if (i != -1)
	345	sysrq_key_table[i] = op_p;
	346	}
	347
	348	/*
bf36b901 AM	349	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	350	* by sysrq key handlers, as they are inside of the lock
1da177e4	351	*/
7d12e780	352	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	353	{
	354	struct sysrq_key_op *op_p;
	355	int orig_log_level;
bf36b901	356	int i;
1da177e4 LT	357	unsigned long flags;
	358
	359	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	360	orig_log_level = console_loglevel;
	361	console_loglevel = 7;
	362	printk(KERN_INFO "SysRq : ");
	363
	364	op_p = __sysrq_get_key_op(key);
	365	if (op_p) {
bf36b901 AM	366	/*
	367	* Should we check for enabled operations (/proc/sysrq-trigger
	368	* should not) and is the invoked operation enabled?
	369	*/
1da177e4 LT	370	if (!check_mask \|\| sysrq_enabled == 1 \|\|
1da177e4 LT	371	(sysrq_enabled & op_p->enable_mask)) {
bf36b901	372	printk("%s\n", op_p->action_msg);
1da177e4	373	console_loglevel = orig_log_level;
7d12e780	374	op_p->handler(key, tty);
bf36b901	375	} else {
1da177e4	376	printk("This sysrq operation is disabled.\n");
bf36b901	377	}
1da177e4 LT	378	} else {
	379	printk("HELP : ");
	380	/* Only print the help msg once per handler */
bf36b901 AM	381	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	382	if (sysrq_key_table[i]) {
	383	int j;
	384
	385	for (j = 0; sysrq_key_table[i] !=
	386	sysrq_key_table[j]; j++)
	387	;
	388	if (j != i)
	389	continue;
	390	printk("%s ", sysrq_key_table[i]->help_msg);
	391	}
1da177e4	392	}
bf36b901	393	printk("\n");
1da177e4 LT	394	console_loglevel = orig_log_level;
	395	}
	396	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	397	}
	398
	399	/*
	400	* This function is called by the keyboard handler when SysRq is pressed
	401	* and any other keycode arrives.
	402	*/
7d12e780	403	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4 LT	404	{
	405	if (!sysrq_enabled)
	406	return;
7d12e780	407	__handle_sysrq(key, tty, 1);
1da177e4	408	}
bf36b901	409	EXPORT_SYMBOL(handle_sysrq);
1da177e4	410
cf62ddce	411	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	412	struct sysrq_key_op *remove_op_p)
bf36b901 AM	413	{
1da177e4 LT	414
	415	int retval;
	416	unsigned long flags;
	417
	418	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	419	if (__sysrq_get_key_op(key) == remove_op_p) {
	420	__sysrq_put_key_op(key, insert_op_p);
	421	retval = 0;
	422	} else {
	423	retval = -1;
	424	}
	425	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	426	return retval;
	427	}
	428
	429	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	430	{
	431	return __sysrq_swap_key_ops(key, op_p, NULL);
	432	}
bf36b901	433	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	434
	435	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	436	{
	437	return __sysrq_swap_key_ops(key, NULL, op_p);
	438	}
1da177e4	439	EXPORT_SYMBOL(unregister_sysrq_key);