[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 <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 pt_regs *pt_regs,
				  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 pt_regs *pt_regs,
			     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 pt_regs *pt_regs,
			       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 pt_regs *pt_regs,
				struct tty_struct *tty)
{
	crash_kexec(pt_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 pt_regs *pt_regs,
				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 pt_regs *pt_regs,
			      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 pt_regs *pt_regs,
				 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 pt_regs *pt_regs,
				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 pt_regs *pt_regs,
				  struct tty_struct *tty)
{
	if (pt_regs)
		show_regs(pt_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 pt_regs *pt_regs,
				   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 pt_regs *pt_regs,
				 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 pt_regs *pt_regs,
			      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 pt_regs *pt_regs,
			      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 pt_regs *pt_regs,
			      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 pt_regs *pt_regs,
				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 pt_regs *pt_regs, 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, pt_regs, 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 pt_regs *pt_regs, struct tty_struct *tty)
{
	if (!sysrq_enabled)
		return;
	__handle_sysrq(key, pt_regs, 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>
1da177e4 LT	38
	39	#include <asm/ptrace.h>
	40
	41	/* Whether we react on sysrq keys or just ignore them */
	42	int sysrq_enabled = 1;
	43
1da177e4	44	static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
bf36b901	45	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 LT	60	#ifdef CONFIG_VT
1da177e4 LT	61	static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
bf36b901	62	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
1da177e4	79	static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
bf36b901	80	struct tty_struct *tty)
1da177e4 LT	81	{
	82	struct kbd_struct *kbd = &kbd_table[fg_console];
	83
	84	if (kbd)
	85	kbd->kbdmode = VC_XLATE;
	86	}
	87	static struct sysrq_key_op sysrq_unraw_op = {
	88	.handler = sysrq_handle_unraw,
	89	.help_msg = "unRaw",
	90	.action_msg = "Keyboard mode set to XLATE",
	91	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	92	};
bf36b901 AM	93	#else
bf36b901 AM	94	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	95	#endif /* CONFIG_VT */
1da177e4 LT	96
86b1ae38	97	#ifdef CONFIG_KEXEC
86b1ae38 HN	98	static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
	99	struct tty_struct *tty)
	100	{
6e274d14	101	crash_kexec(pt_regs);
86b1ae38 HN	102	}
	103	static struct sysrq_key_op sysrq_crashdump_op = {
	104	.handler = sysrq_handle_crashdump,
	105	.help_msg = "Crashdump",
	106	.action_msg = "Trigger a crashdump",
	107	.enable_mask = SYSRQ_ENABLE_DUMP,
	108	};
bf36b901 AM	109	#else
bf36b901 AM	110	#define sysrq_crashdump_op ((struct sysrq_key_op )0)
86b1ae38 HN	111	#endif
86b1ae38 HN	112
1da177e4	113	static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
bf36b901	114	struct tty_struct *tty)
1da177e4	115	{
b2e9c7d0	116	lockdep_off();
1da177e4	117	local_irq_enable();
4de8b9b7	118	emergency_restart();
1da177e4	119	}
1da177e4 LT	120	static struct sysrq_key_op sysrq_reboot_op = {
	121	.handler = sysrq_handle_reboot,
	122	.help_msg = "reBoot",
	123	.action_msg = "Resetting",
	124	.enable_mask = SYSRQ_ENABLE_BOOT,
	125	};
	126
	127	static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
bf36b901	128	struct tty_struct *tty)
1da177e4 LT	129	{
	130	emergency_sync();
	131	}
1da177e4 LT	132	static struct sysrq_key_op sysrq_sync_op = {
	133	.handler = sysrq_handle_sync,
	134	.help_msg = "Sync",
	135	.action_msg = "Emergency Sync",
	136	.enable_mask = SYSRQ_ENABLE_SYNC,
	137	};
	138
	139	static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
bf36b901	140	struct tty_struct *tty)
1da177e4 LT	141	{
	142	emergency_remount();
	143	}
1da177e4 LT	144	static struct sysrq_key_op sysrq_mountro_op = {
	145	.handler = sysrq_handle_mountro,
	146	.help_msg = "Unmount",
	147	.action_msg = "Emergency Remount R/O",
	148	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	149	};
	150
8c64580d	151	#ifdef CONFIG_LOCKDEP
bf36b901 AM	152	static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
bf36b901 AM	153	struct tty_struct *tty)
de5097c2	154	{
9a11b49a	155	debug_show_all_locks();
de5097c2	156	}
8c64580d	157
de5097c2 IM	158	static struct sysrq_key_op sysrq_showlocks_op = {
	159	.handler = sysrq_handle_showlocks,
	160	.help_msg = "show-all-locks(D)",
	161	.action_msg = "Show Locks Held",
	162	};
bf36b901 AM	163	#else
bf36b901 AM	164	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	165	#endif
1da177e4	166
1da177e4	167	static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
bf36b901	168	struct tty_struct *tty)
1da177e4 LT	169	{
	170	if (pt_regs)
	171	show_regs(pt_regs);
	172	}
	173	static struct sysrq_key_op sysrq_showregs_op = {
	174	.handler = sysrq_handle_showregs,
	175	.help_msg = "showPc",
	176	.action_msg = "Show Regs",
	177	.enable_mask = SYSRQ_ENABLE_DUMP,
	178	};
	179
1da177e4	180	static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
bf36b901	181	struct tty_struct *tty)
1da177e4 LT	182	{
	183	show_state();
	184	}
	185	static struct sysrq_key_op sysrq_showstate_op = {
	186	.handler = sysrq_handle_showstate,
	187	.help_msg = "showTasks",
	188	.action_msg = "Show State",
	189	.enable_mask = SYSRQ_ENABLE_DUMP,
	190	};
	191
1da177e4	192	static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
bf36b901	193	struct tty_struct *tty)
1da177e4 LT	194	{
	195	show_mem();
	196	}
	197	static struct sysrq_key_op sysrq_showmem_op = {
	198	.handler = sysrq_handle_showmem,
	199	.help_msg = "showMem",
	200	.action_msg = "Show Memory",
	201	.enable_mask = SYSRQ_ENABLE_DUMP,
	202	};
	203
bf36b901 AM	204	/*
	205	* Signal sysrq helper function. Sends a signal to all user processes.
	206	*/
1da177e4 LT	207	static void send_sig_all(int sig)
	208	{
	209	struct task_struct *p;
	210
	211	for_each_process(p) {
f400e198	212	if (p->mm && !is_init(p))
1da177e4 LT	213	/* Not swapper, init nor kernel thread */
	214	force_sig(sig, p);
	215	}
	216	}
	217
	218	static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
bf36b901	219	struct tty_struct *tty)
1da177e4 LT	220	{
	221	send_sig_all(SIGTERM);
	222	console_loglevel = 8;
	223	}
	224	static struct sysrq_key_op sysrq_term_op = {
	225	.handler = sysrq_handle_term,
	226	.help_msg = "tErm",
	227	.action_msg = "Terminate All Tasks",
	228	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	229	};
	230
	231	static void moom_callback(void *ignored)
	232	{
bf36b901 AM	233	out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
bf36b901 AM	234	GFP_KERNEL, 0);
1da177e4 LT	235	}
	236
	237	static DECLARE_WORK(moom_work, moom_callback, NULL);
	238
	239	static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
	240	struct tty_struct *tty)
	241	{
	242	schedule_work(&moom_work);
	243	}
	244	static struct sysrq_key_op sysrq_moom_op = {
	245	.handler = sysrq_handle_moom,
	246	.help_msg = "Full",
	247	.action_msg = "Manual OOM execution",
	248	};
	249
	250	static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
bf36b901	251	struct tty_struct *tty)
1da177e4 LT	252	{
	253	send_sig_all(SIGKILL);
	254	console_loglevel = 8;
	255	}
	256	static struct sysrq_key_op sysrq_kill_op = {
	257	.handler = sysrq_handle_kill,
	258	.help_msg = "kIll",
	259	.action_msg = "Kill All Tasks",
	260	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	261	};
	262
1da177e4 LT	263	static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
	264	struct tty_struct *tty)
	265	{
	266	normalize_rt_tasks();
	267	}
	268	static struct sysrq_key_op sysrq_unrt_op = {
	269	.handler = sysrq_handle_unrt,
	270	.help_msg = "Nice",
	271	.action_msg = "Nice All RT Tasks",
	272	.enable_mask = SYSRQ_ENABLE_RTNICE,
	273	};
	274
	275	/* Key Operations table and lock */
	276	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	277
	278	static struct sysrq_key_op *sysrq_key_table[36] = {
	279	&sysrq_loglevel_op, /* 0 */
	280	&sysrq_loglevel_op, /* 1 */
	281	&sysrq_loglevel_op, /* 2 */
	282	&sysrq_loglevel_op, /* 3 */
	283	&sysrq_loglevel_op, /* 4 */
	284	&sysrq_loglevel_op, /* 5 */
	285	&sysrq_loglevel_op, /* 6 */
	286	&sysrq_loglevel_op, /* 7 */
	287	&sysrq_loglevel_op, /* 8 */
	288	&sysrq_loglevel_op, /* 9 */
	289
	290	/*
	291	* Don't use for system provided sysrqs, it is handled specially on
	292	* sparc and will never arrive
	293	*/
	294	NULL, /* a */
	295	&sysrq_reboot_op, /* b */
	296	&sysrq_crashdump_op, /* c */
	297	&sysrq_showlocks_op, /* d */
	298	&sysrq_term_op, /* e */
	299	&sysrq_moom_op, /* f */
	300	NULL, /* g */
	301	NULL, /* h */
	302	&sysrq_kill_op, /* i */
	303	NULL, /* j */
	304	&sysrq_SAK_op, /* k */
	305	NULL, /* l */
	306	&sysrq_showmem_op, /* m */
	307	&sysrq_unrt_op, /* n */
	308	/* This will often be registered as 'Off' at init time */
	309	NULL, /* o */
	310	&sysrq_showregs_op, /* p */
	311	NULL, /* q */
	312	&sysrq_unraw_op, /* r */
	313	&sysrq_sync_op, /* s */
	314	&sysrq_showstate_op, /* t */
	315	&sysrq_mountro_op, /* u */
	316	/* May be assigned at init time by SMP VOYAGER */
	317	NULL, /* v */
	318	NULL, /* w */
	319	NULL, /* x */
	320	NULL, /* y */
	321	NULL /* z */
1da177e4 LT	322	};
	323
	324	/* key2index calculation, -1 on invalid index */
bf36b901 AM	325	static int sysrq_key_table_key2index(int key)
bf36b901 AM	326	{
1da177e4	327	int retval;
bf36b901 AM	328
bf36b901 AM	329	if ((key >= '0') && (key <= '9'))
1da177e4	330	retval = key - '0';
bf36b901	331	else if ((key >= 'a') && (key <= 'z'))
1da177e4	332	retval = key + 10 - 'a';
bf36b901	333	else
1da177e4	334	retval = -1;
1da177e4 LT	335	return retval;
	336	}
	337
	338	/*
	339	* get and put functions for the table, exposed to modules.
	340	*/
bf36b901 AM	341	struct sysrq_key_op *__sysrq_get_key_op(int key)
	342	{
	343	struct sysrq_key_op *op_p = NULL;
1da177e4	344	int i;
bf36b901	345
1da177e4	346	i = sysrq_key_table_key2index(key);
bf36b901 AM	347	if (i != -1)
bf36b901 AM	348	op_p = sysrq_key_table[i];
1da177e4 LT	349	return op_p;
	350	}
	351
bf36b901 AM	352	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	353	{
	354	int i = sysrq_key_table_key2index(key);
1da177e4	355
1da177e4 LT	356	if (i != -1)
	357	sysrq_key_table[i] = op_p;
	358	}
	359
	360	/*
bf36b901 AM	361	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	362	* by sysrq key handlers, as they are inside of the lock
1da177e4	363	*/
bf36b901 AM	364	void __handle_sysrq(int key, struct pt_regs pt_regs, struct tty_struct tty,
bf36b901 AM	365	int check_mask)
1da177e4 LT	366	{
	367	struct sysrq_key_op *op_p;
	368	int orig_log_level;
bf36b901	369	int i;
1da177e4 LT	370	unsigned long flags;
	371
	372	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	373	orig_log_level = console_loglevel;
	374	console_loglevel = 7;
	375	printk(KERN_INFO "SysRq : ");
	376
	377	op_p = __sysrq_get_key_op(key);
	378	if (op_p) {
bf36b901 AM	379	/*
	380	* Should we check for enabled operations (/proc/sysrq-trigger
	381	* should not) and is the invoked operation enabled?
	382	*/
1da177e4 LT	383	if (!check_mask \|\| sysrq_enabled == 1 \|\|
1da177e4 LT	384	(sysrq_enabled & op_p->enable_mask)) {
bf36b901	385	printk("%s\n", op_p->action_msg);
1da177e4 LT	386	console_loglevel = orig_log_level;
1da177e4 LT	387	op_p->handler(key, pt_regs, tty);
bf36b901	388	} else {
1da177e4	389	printk("This sysrq operation is disabled.\n");
bf36b901	390	}
1da177e4 LT	391	} else {
	392	printk("HELP : ");
	393	/* Only print the help msg once per handler */
bf36b901 AM	394	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	395	if (sysrq_key_table[i]) {
	396	int j;
	397
	398	for (j = 0; sysrq_key_table[i] !=
	399	sysrq_key_table[j]; j++)
	400	;
	401	if (j != i)
	402	continue;
	403	printk("%s ", sysrq_key_table[i]->help_msg);
	404	}
1da177e4	405	}
bf36b901	406	printk("\n");
1da177e4 LT	407	console_loglevel = orig_log_level;
	408	}
	409	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	410	}
	411
	412	/*
	413	* This function is called by the keyboard handler when SysRq is pressed
	414	* and any other keycode arrives.
	415	*/
1da177e4 LT	416	void handle_sysrq(int key, struct pt_regs pt_regs, struct tty_struct tty)
	417	{
	418	if (!sysrq_enabled)
	419	return;
	420	__handle_sysrq(key, pt_regs, tty, 1);
	421	}
bf36b901	422	EXPORT_SYMBOL(handle_sysrq);
1da177e4	423
cf62ddce	424	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	425	struct sysrq_key_op *remove_op_p)
bf36b901 AM	426	{
1da177e4 LT	427
	428	int retval;
	429	unsigned long flags;
	430
	431	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	432	if (__sysrq_get_key_op(key) == remove_op_p) {
	433	__sysrq_put_key_op(key, insert_op_p);
	434	retval = 0;
	435	} else {
	436	retval = -1;
	437	}
	438	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	439	return retval;
	440	}
	441
	442	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	443	{
	444	return __sysrq_swap_key_ops(key, op_p, NULL);
	445	}
bf36b901	446	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	447
	448	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	449	{
	450	return __sysrq_swap_key_ops(key, NULL, op_p);
	451	}
1da177e4	452	EXPORT_SYMBOL(unregister_sysrq_key);