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