[linux-2.6-block.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>

/* 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(void *ignored)
{
	out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
			GFP_KERNEL, 0);
}

static DECLARE_WORK(moom_work, moom_callback, NULL);

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