[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 <linux/irq.h>

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

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

static int __read_mostly sysrq_always_enabled;

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

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

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

	return 1;
}

__setup("sysrq_always_enabled", sysrq_always_enabled_setup);


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

#ifdef CONFIG_VT
static void sysrq_handle_SAK(int key, struct tty_struct *tty)
{
	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_showstate_blocked(int key, struct tty_struct *tty)
{
	show_state_filter(TASK_UNINTERRUPTIBLE);
}
static struct sysrq_key_op sysrq_showstate_blocked_op = {
	.handler	= sysrq_handle_showstate_blocked,
	.help_msg	= "showBlockedTasks",
	.action_msg	= "Show Blocked State",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};


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

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

	for_each_process(p) {
		if (p->mm && !is_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 */
	&sysrq_showstate_blocked_op,	/* 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_on_mask(op_p->enable_mask)) {
			printk("%s\n", op_p->action_msg);
			console_loglevel = orig_log_level;
			op_p->handler(key, tty);
		} else {
			printk("This sysrq operation is disabled.\n");
		}
	} else {
		printk("HELP : ");
		/* Only print the help msg once per handler */
		for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
			if (sysrq_key_table[i]) {
				int j;

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

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

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

	int retval;
	unsigned long flags;

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

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

int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
{
	return __sysrq_swap_key_ops(key, NULL, op_p);
}
EXPORT_SYMBOL(unregister_sysrq_key);
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
1da177e4 LT	43	/* Whether we react on sysrq keys or just ignore them */
5d6f647f IM	44	int __read_mostly __sysrq_enabled = 1;
	45
	46	static int __read_mostly sysrq_always_enabled;
	47
	48	int sysrq_on(void)
	49	{
	50	return __sysrq_enabled \|\| sysrq_always_enabled;
	51	}
	52
	53	/*
	54	* A value of 1 means 'all', other nonzero values are an op mask:
	55	*/
	56	static inline int sysrq_on_mask(int mask)
	57	{
	58	return sysrq_always_enabled \|\| __sysrq_enabled == 1 \|\|
	59	(__sysrq_enabled & mask);
	60	}
	61
	62	static int __init sysrq_always_enabled_setup(char *str)
	63	{
	64	sysrq_always_enabled = 1;
	65	printk(KERN_INFO "debug: sysrq always enabled.\n");
	66
	67	return 1;
	68	}
	69
	70	__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
	71
1da177e4	72
7d12e780	73	static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
1da177e4 LT	74	{
	75	int i;
	76	i = key - '0';
	77	console_loglevel = 7;
	78	printk("Loglevel set to %d\n", i);
	79	console_loglevel = i;
bf36b901	80	}
1da177e4 LT	81	static struct sysrq_key_op sysrq_loglevel_op = {
	82	.handler = sysrq_handle_loglevel,
	83	.help_msg = "loglevel0-8",
	84	.action_msg = "Changing Loglevel",
	85	.enable_mask = SYSRQ_ENABLE_LOG,
	86	};
	87
1da177e4	88	#ifdef CONFIG_VT
7d12e780	89	static void sysrq_handle_SAK(int key, struct tty_struct *tty)
1da177e4 LT	90	{
	91	if (tty)
	92	do_SAK(tty);
	93	reset_vc(vc_cons[fg_console].d);
	94	}
	95	static struct sysrq_key_op sysrq_SAK_op = {
	96	.handler = sysrq_handle_SAK,
	97	.help_msg = "saK",
	98	.action_msg = "SAK",
	99	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	100	};
bf36b901 AM	101	#else
bf36b901 AM	102	#define sysrq_SAK_op ((struct sysrq_key_op )0)
1da177e4 LT	103	#endif
	104
	105	#ifdef CONFIG_VT
7d12e780	106	static void sysrq_handle_unraw(int key, struct tty_struct *tty)
1da177e4 LT	107	{
	108	struct kbd_struct *kbd = &kbd_table[fg_console];
	109
	110	if (kbd)
	111	kbd->kbdmode = VC_XLATE;
	112	}
	113	static struct sysrq_key_op sysrq_unraw_op = {
	114	.handler = sysrq_handle_unraw,
	115	.help_msg = "unRaw",
	116	.action_msg = "Keyboard mode set to XLATE",
	117	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	118	};
bf36b901 AM	119	#else
bf36b901 AM	120	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	121	#endif /* CONFIG_VT */
1da177e4 LT	122
86b1ae38	123	#ifdef CONFIG_KEXEC
7d12e780	124	static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
86b1ae38	125	{
7d12e780	126	crash_kexec(get_irq_regs());
86b1ae38 HN	127	}
	128	static struct sysrq_key_op sysrq_crashdump_op = {
	129	.handler = sysrq_handle_crashdump,
	130	.help_msg = "Crashdump",
	131	.action_msg = "Trigger a crashdump",
	132	.enable_mask = SYSRQ_ENABLE_DUMP,
	133	};
bf36b901 AM	134	#else
bf36b901 AM	135	#define sysrq_crashdump_op ((struct sysrq_key_op )0)
86b1ae38 HN	136	#endif
86b1ae38 HN	137
7d12e780	138	static void sysrq_handle_reboot(int key, struct tty_struct *tty)
1da177e4	139	{
b2e9c7d0	140	lockdep_off();
1da177e4	141	local_irq_enable();
4de8b9b7	142	emergency_restart();
1da177e4	143	}
1da177e4 LT	144	static struct sysrq_key_op sysrq_reboot_op = {
	145	.handler = sysrq_handle_reboot,
	146	.help_msg = "reBoot",
	147	.action_msg = "Resetting",
	148	.enable_mask = SYSRQ_ENABLE_BOOT,
	149	};
	150
7d12e780	151	static void sysrq_handle_sync(int key, struct tty_struct *tty)
1da177e4 LT	152	{
	153	emergency_sync();
	154	}
1da177e4 LT	155	static struct sysrq_key_op sysrq_sync_op = {
	156	.handler = sysrq_handle_sync,
	157	.help_msg = "Sync",
	158	.action_msg = "Emergency Sync",
	159	.enable_mask = SYSRQ_ENABLE_SYNC,
	160	};
	161
7d12e780	162	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	163	{
	164	emergency_remount();
	165	}
1da177e4 LT	166	static struct sysrq_key_op sysrq_mountro_op = {
	167	.handler = sysrq_handle_mountro,
	168	.help_msg = "Unmount",
	169	.action_msg = "Emergency Remount R/O",
	170	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	171	};
	172
8c64580d	173	#ifdef CONFIG_LOCKDEP
7d12e780	174	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	175	{
9a11b49a	176	debug_show_all_locks();
de5097c2	177	}
8c64580d	178
de5097c2 IM	179	static struct sysrq_key_op sysrq_showlocks_op = {
	180	.handler = sysrq_handle_showlocks,
	181	.help_msg = "show-all-locks(D)",
	182	.action_msg = "Show Locks Held",
	183	};
bf36b901 AM	184	#else
bf36b901 AM	185	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	186	#endif
1da177e4	187
7d12e780	188	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	189	{
7d12e780 DH	190	struct pt_regs *regs = get_irq_regs();
	191	if (regs)
	192	show_regs(regs);
1da177e4 LT	193	}
	194	static struct sysrq_key_op sysrq_showregs_op = {
	195	.handler = sysrq_handle_showregs,
	196	.help_msg = "showPc",
	197	.action_msg = "Show Regs",
	198	.enable_mask = SYSRQ_ENABLE_DUMP,
	199	};
	200
7d12e780	201	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	202	{
	203	show_state();
	204	}
	205	static struct sysrq_key_op sysrq_showstate_op = {
	206	.handler = sysrq_handle_showstate,
	207	.help_msg = "showTasks",
	208	.action_msg = "Show State",
	209	.enable_mask = SYSRQ_ENABLE_DUMP,
	210	};
	211
e59e2ae2 IM	212	static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
	213	{
	214	show_state_filter(TASK_UNINTERRUPTIBLE);
	215	}
	216	static struct sysrq_key_op sysrq_showstate_blocked_op = {
	217	.handler = sysrq_handle_showstate_blocked,
	218	.help_msg = "showBlockedTasks",
	219	.action_msg = "Show Blocked State",
	220	.enable_mask = SYSRQ_ENABLE_DUMP,
	221	};
	222
	223
7d12e780	224	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	225	{
	226	show_mem();
	227	}
	228	static struct sysrq_key_op sysrq_showmem_op = {
	229	.handler = sysrq_handle_showmem,
	230	.help_msg = "showMem",
	231	.action_msg = "Show Memory",
	232	.enable_mask = SYSRQ_ENABLE_DUMP,
	233	};
	234
bf36b901 AM	235	/*
	236	* Signal sysrq helper function. Sends a signal to all user processes.
	237	*/
1da177e4 LT	238	static void send_sig_all(int sig)
	239	{
	240	struct task_struct *p;
	241
	242	for_each_process(p) {
f400e198	243	if (p->mm && !is_init(p))
1da177e4 LT	244	/* Not swapper, init nor kernel thread */
	245	force_sig(sig, p);
	246	}
	247	}
	248
7d12e780	249	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	250	{
	251	send_sig_all(SIGTERM);
	252	console_loglevel = 8;
	253	}
	254	static struct sysrq_key_op sysrq_term_op = {
	255	.handler = sysrq_handle_term,
	256	.help_msg = "tErm",
	257	.action_msg = "Terminate All Tasks",
	258	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	259	};
	260
65f27f38	261	static void moom_callback(struct work_struct *ignored)
1da177e4	262	{
bf36b901 AM	263	out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
bf36b901 AM	264	GFP_KERNEL, 0);
1da177e4 LT	265	}
1da177e4 LT	266
65f27f38	267	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	268
7d12e780	269	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	270	{
	271	schedule_work(&moom_work);
	272	}
	273	static struct sysrq_key_op sysrq_moom_op = {
	274	.handler = sysrq_handle_moom,
	275	.help_msg = "Full",
	276	.action_msg = "Manual OOM execution",
	277	};
	278
7d12e780	279	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	280	{
	281	send_sig_all(SIGKILL);
	282	console_loglevel = 8;
	283	}
	284	static struct sysrq_key_op sysrq_kill_op = {
	285	.handler = sysrq_handle_kill,
	286	.help_msg = "kIll",
	287	.action_msg = "Kill All Tasks",
	288	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	289	};
	290
7d12e780	291	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	292	{
	293	normalize_rt_tasks();
	294	}
	295	static struct sysrq_key_op sysrq_unrt_op = {
	296	.handler = sysrq_handle_unrt,
	297	.help_msg = "Nice",
	298	.action_msg = "Nice All RT Tasks",
	299	.enable_mask = SYSRQ_ENABLE_RTNICE,
	300	};
	301
	302	/* Key Operations table and lock */
	303	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	304
	305	static struct sysrq_key_op *sysrq_key_table[36] = {
	306	&sysrq_loglevel_op, /* 0 */
	307	&sysrq_loglevel_op, /* 1 */
	308	&sysrq_loglevel_op, /* 2 */
	309	&sysrq_loglevel_op, /* 3 */
	310	&sysrq_loglevel_op, /* 4 */
	311	&sysrq_loglevel_op, /* 5 */
	312	&sysrq_loglevel_op, /* 6 */
	313	&sysrq_loglevel_op, /* 7 */
	314	&sysrq_loglevel_op, /* 8 */
	315	&sysrq_loglevel_op, /* 9 */
	316
	317	/*
	318	* Don't use for system provided sysrqs, it is handled specially on
	319	* sparc and will never arrive
	320	*/
	321	NULL, /* a */
	322	&sysrq_reboot_op, /* b */
	323	&sysrq_crashdump_op, /* c */
	324	&sysrq_showlocks_op, /* d */
	325	&sysrq_term_op, /* e */
	326	&sysrq_moom_op, /* f */
	327	NULL, /* g */
	328	NULL, /* h */
	329	&sysrq_kill_op, /* i */
	330	NULL, /* j */
	331	&sysrq_SAK_op, /* k */
	332	NULL, /* l */
	333	&sysrq_showmem_op, /* m */
	334	&sysrq_unrt_op, /* n */
	335	/* This will often be registered as 'Off' at init time */
	336	NULL, /* o */
	337	&sysrq_showregs_op, /* p */
	338	NULL, /* q */
	339	&sysrq_unraw_op, /* r */
	340	&sysrq_sync_op, /* s */
	341	&sysrq_showstate_op, /* t */
	342	&sysrq_mountro_op, /* u */
	343	/* May be assigned at init time by SMP VOYAGER */
	344	NULL, /* v */
	345	NULL, /* w */
e59e2ae2	346	&sysrq_showstate_blocked_op, /* x */
bf36b901 AM	347	NULL, /* y */
bf36b901 AM	348	NULL /* z */
1da177e4 LT	349	};
	350
	351	/* key2index calculation, -1 on invalid index */
bf36b901 AM	352	static int sysrq_key_table_key2index(int key)
bf36b901 AM	353	{
1da177e4	354	int retval;
bf36b901 AM	355
bf36b901 AM	356	if ((key >= '0') && (key <= '9'))
1da177e4	357	retval = key - '0';
bf36b901	358	else if ((key >= 'a') && (key <= 'z'))
1da177e4	359	retval = key + 10 - 'a';
bf36b901	360	else
1da177e4	361	retval = -1;
1da177e4 LT	362	return retval;
	363	}
	364
	365	/*
	366	* get and put functions for the table, exposed to modules.
	367	*/
bf36b901 AM	368	struct sysrq_key_op *__sysrq_get_key_op(int key)
	369	{
	370	struct sysrq_key_op *op_p = NULL;
1da177e4	371	int i;
bf36b901	372
1da177e4	373	i = sysrq_key_table_key2index(key);
bf36b901 AM	374	if (i != -1)
bf36b901 AM	375	op_p = sysrq_key_table[i];
1da177e4 LT	376	return op_p;
	377	}
	378
bf36b901 AM	379	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	380	{
	381	int i = sysrq_key_table_key2index(key);
1da177e4	382
1da177e4 LT	383	if (i != -1)
	384	sysrq_key_table[i] = op_p;
	385	}
	386
	387	/*
bf36b901 AM	388	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	389	* by sysrq key handlers, as they are inside of the lock
1da177e4	390	*/
7d12e780	391	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	392	{
	393	struct sysrq_key_op *op_p;
	394	int orig_log_level;
bf36b901	395	int i;
1da177e4 LT	396	unsigned long flags;
	397
	398	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	399	orig_log_level = console_loglevel;
	400	console_loglevel = 7;
	401	printk(KERN_INFO "SysRq : ");
	402
	403	op_p = __sysrq_get_key_op(key);
	404	if (op_p) {
bf36b901 AM	405	/*
	406	* Should we check for enabled operations (/proc/sysrq-trigger
	407	* should not) and is the invoked operation enabled?
	408	*/
5d6f647f	409	if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
bf36b901	410	printk("%s\n", op_p->action_msg);
1da177e4	411	console_loglevel = orig_log_level;
7d12e780	412	op_p->handler(key, tty);
bf36b901	413	} else {
1da177e4	414	printk("This sysrq operation is disabled.\n");
bf36b901	415	}
1da177e4 LT	416	} else {
	417	printk("HELP : ");
	418	/* Only print the help msg once per handler */
bf36b901 AM	419	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	420	if (sysrq_key_table[i]) {
	421	int j;
	422
	423	for (j = 0; sysrq_key_table[i] !=
	424	sysrq_key_table[j]; j++)
	425	;
	426	if (j != i)
	427	continue;
	428	printk("%s ", sysrq_key_table[i]->help_msg);
	429	}
1da177e4	430	}
bf36b901	431	printk("\n");
1da177e4 LT	432	console_loglevel = orig_log_level;
	433	}
	434	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	435	}
	436
	437	/*
	438	* This function is called by the keyboard handler when SysRq is pressed
	439	* and any other keycode arrives.
	440	*/
7d12e780	441	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4	442	{
5d6f647f IM	443	if (sysrq_on())
5d6f647f IM	444	__handle_sysrq(key, tty, 1);
1da177e4	445	}
bf36b901	446	EXPORT_SYMBOL(handle_sysrq);
1da177e4	447
cf62ddce	448	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	449	struct sysrq_key_op *remove_op_p)
bf36b901 AM	450	{
1da177e4 LT	451
	452	int retval;
	453	unsigned long flags;
	454
	455	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	456	if (__sysrq_get_key_op(key) == remove_op_p) {
	457	__sysrq_put_key_op(key, insert_op_p);
	458	retval = 0;
	459	} else {
	460	retval = -1;
	461	}
	462	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	463	return retval;
	464	}
	465
	466	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	467	{
	468	return __sysrq_swap_key_ops(key, op_p, NULL);
	469	}
bf36b901	470	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	471
	472	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	473	{
	474	return __sysrq_swap_key_ops(key, NULL, op_p);
	475	}
1da177e4	476	EXPORT_SYMBOL(unregister_sysrq_key);