[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 <[email protected]>
 *	based on ideas by Pavel Machek <[email protected]>
 *
 *	(c) 2000 Crutcher Dunnavant <[email protected]>
 *	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/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 <linux/hrtimer.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)
{
	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
	schedule_work(SAK_work);
}
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_show_timers(int key, struct tty_struct *tty)
{
	sysrq_timer_list_show();
}

static struct sysrq_key_op sysrq_show_timers_op = {
	.handler	= sysrq_handle_show_timers,
	.help_msg	= "show-all-timers(Q)",
	.action_msg	= "Show Pending Timers",
};

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	= "shoW-blocked-tasks",
	.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 */

	/*
	 * a: 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 & ibm_emac driver debug */
	&sysrq_showlocks_op,		/* d */
	&sysrq_term_op,			/* e */
	&sysrq_moom_op,			/* f */
	/* g: May be registered by ppc for kgdb */
	NULL,				/* g */
	NULL,				/* h */
	&sysrq_kill_op,			/* i */
	NULL,				/* j */
	&sysrq_SAK_op,			/* k */
	NULL,				/* l */
	&sysrq_showmem_op,		/* m */
	&sysrq_unrt_op,			/* n */
	/* o: This will often be registered as 'Off' at init time */
	NULL,				/* o */
	&sysrq_showregs_op,		/* p */
	&sysrq_show_timers_op,		/* q */
	&sysrq_unraw_op,		/* r */
	&sysrq_sync_op,			/* s */
	&sysrq_showstate_op,		/* t */
	&sysrq_mountro_op,		/* u */
	/* v: May be registered at init time by SMP VOYAGER */
	NULL,				/* v */
	&sysrq_showstate_blocked_op,	/* w */
	/* x: May be registered on ppc/powerpc for xmon */
	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_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 <[email protected]>
	8	* based on ideas by Pavel Machek <[email protected]>
	9	*
	10	* (c) 2000 Crutcher Dunnavant <[email protected]>
	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>
1da177e4 LT	27	#include <linux/kernel.h>
	28	#include <linux/module.h>
	29	#include <linux/suspend.h>
	30	#include <linux/writeback.h>
	31	#include <linux/buffer_head.h> /* for fsync_bdev() */
	32	#include <linux/swap.h>
	33	#include <linux/spinlock.h>
	34	#include <linux/vt_kern.h>
	35	#include <linux/workqueue.h>
86b1ae38	36	#include <linux/kexec.h>
7d12e780	37	#include <linux/irq.h>
88ad0bf6	38	#include <linux/hrtimer.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	90	{
8b6312f4	91	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
8b6312f4	92	schedule_work(SAK_work);
1da177e4 LT	93	}
	94	static struct sysrq_key_op sysrq_SAK_op = {
	95	.handler = sysrq_handle_SAK,
	96	.help_msg = "saK",
	97	.action_msg = "SAK",
	98	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	99	};
bf36b901 AM	100	#else
bf36b901 AM	101	#define sysrq_SAK_op ((struct sysrq_key_op )0)
1da177e4 LT	102	#endif
	103
	104	#ifdef CONFIG_VT
7d12e780	105	static void sysrq_handle_unraw(int key, struct tty_struct *tty)
1da177e4 LT	106	{
	107	struct kbd_struct *kbd = &kbd_table[fg_console];
	108
	109	if (kbd)
	110	kbd->kbdmode = VC_XLATE;
	111	}
	112	static struct sysrq_key_op sysrq_unraw_op = {
	113	.handler = sysrq_handle_unraw,
	114	.help_msg = "unRaw",
	115	.action_msg = "Keyboard mode set to XLATE",
	116	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	117	};
bf36b901 AM	118	#else
bf36b901 AM	119	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	120	#endif /* CONFIG_VT */
1da177e4 LT	121
86b1ae38	122	#ifdef CONFIG_KEXEC
7d12e780	123	static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
86b1ae38	124	{
7d12e780	125	crash_kexec(get_irq_regs());
86b1ae38 HN	126	}
	127	static struct sysrq_key_op sysrq_crashdump_op = {
	128	.handler = sysrq_handle_crashdump,
	129	.help_msg = "Crashdump",
	130	.action_msg = "Trigger a crashdump",
	131	.enable_mask = SYSRQ_ENABLE_DUMP,
	132	};
bf36b901 AM	133	#else
bf36b901 AM	134	#define sysrq_crashdump_op ((struct sysrq_key_op )0)
86b1ae38 HN	135	#endif
86b1ae38 HN	136
7d12e780	137	static void sysrq_handle_reboot(int key, struct tty_struct *tty)
1da177e4	138	{
b2e9c7d0	139	lockdep_off();
1da177e4	140	local_irq_enable();
4de8b9b7	141	emergency_restart();
1da177e4	142	}
1da177e4 LT	143	static struct sysrq_key_op sysrq_reboot_op = {
	144	.handler = sysrq_handle_reboot,
	145	.help_msg = "reBoot",
	146	.action_msg = "Resetting",
	147	.enable_mask = SYSRQ_ENABLE_BOOT,
	148	};
	149
7d12e780	150	static void sysrq_handle_sync(int key, struct tty_struct *tty)
1da177e4 LT	151	{
	152	emergency_sync();
	153	}
1da177e4 LT	154	static struct sysrq_key_op sysrq_sync_op = {
	155	.handler = sysrq_handle_sync,
	156	.help_msg = "Sync",
	157	.action_msg = "Emergency Sync",
	158	.enable_mask = SYSRQ_ENABLE_SYNC,
	159	};
	160
88ad0bf6 IM	161	static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
	162	{
	163	sysrq_timer_list_show();
	164	}
	165
	166	static struct sysrq_key_op sysrq_show_timers_op = {
	167	.handler = sysrq_handle_show_timers,
	168	.help_msg = "show-all-timers(Q)",
	169	.action_msg = "Show Pending Timers",
	170	};
	171
7d12e780	172	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	173	{
	174	emergency_remount();
	175	}
1da177e4 LT	176	static struct sysrq_key_op sysrq_mountro_op = {
	177	.handler = sysrq_handle_mountro,
	178	.help_msg = "Unmount",
	179	.action_msg = "Emergency Remount R/O",
	180	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	181	};
	182
8c64580d	183	#ifdef CONFIG_LOCKDEP
7d12e780	184	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	185	{
9a11b49a	186	debug_show_all_locks();
de5097c2	187	}
8c64580d	188
de5097c2 IM	189	static struct sysrq_key_op sysrq_showlocks_op = {
	190	.handler = sysrq_handle_showlocks,
	191	.help_msg = "show-all-locks(D)",
	192	.action_msg = "Show Locks Held",
	193	};
bf36b901 AM	194	#else
bf36b901 AM	195	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	196	#endif
1da177e4	197
7d12e780	198	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	199	{
7d12e780 DH	200	struct pt_regs *regs = get_irq_regs();
	201	if (regs)
	202	show_regs(regs);
1da177e4 LT	203	}
	204	static struct sysrq_key_op sysrq_showregs_op = {
	205	.handler = sysrq_handle_showregs,
	206	.help_msg = "showPc",
	207	.action_msg = "Show Regs",
	208	.enable_mask = SYSRQ_ENABLE_DUMP,
	209	};
	210
7d12e780	211	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	212	{
	213	show_state();
	214	}
	215	static struct sysrq_key_op sysrq_showstate_op = {
	216	.handler = sysrq_handle_showstate,
	217	.help_msg = "showTasks",
	218	.action_msg = "Show State",
	219	.enable_mask = SYSRQ_ENABLE_DUMP,
	220	};
	221
e59e2ae2 IM	222	static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
	223	{
	224	show_state_filter(TASK_UNINTERRUPTIBLE);
	225	}
	226	static struct sysrq_key_op sysrq_showstate_blocked_op = {
	227	.handler = sysrq_handle_showstate_blocked,
d346cce3	228	.help_msg = "shoW-blocked-tasks",
e59e2ae2 IM	229	.action_msg = "Show Blocked State",
	230	.enable_mask = SYSRQ_ENABLE_DUMP,
	231	};
	232
	233
7d12e780	234	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	235	{
	236	show_mem();
	237	}
	238	static struct sysrq_key_op sysrq_showmem_op = {
	239	.handler = sysrq_handle_showmem,
	240	.help_msg = "showMem",
	241	.action_msg = "Show Memory",
	242	.enable_mask = SYSRQ_ENABLE_DUMP,
	243	};
	244
bf36b901 AM	245	/*
	246	* Signal sysrq helper function. Sends a signal to all user processes.
	247	*/
1da177e4 LT	248	static void send_sig_all(int sig)
	249	{
	250	struct task_struct *p;
	251
	252	for_each_process(p) {
f400e198	253	if (p->mm && !is_init(p))
1da177e4 LT	254	/* Not swapper, init nor kernel thread */
	255	force_sig(sig, p);
	256	}
	257	}
	258
7d12e780	259	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	260	{
	261	send_sig_all(SIGTERM);
	262	console_loglevel = 8;
	263	}
	264	static struct sysrq_key_op sysrq_term_op = {
	265	.handler = sysrq_handle_term,
	266	.help_msg = "tErm",
	267	.action_msg = "Terminate All Tasks",
	268	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	269	};
	270
65f27f38	271	static void moom_callback(struct work_struct *ignored)
1da177e4	272	{
bf36b901 AM	273	out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
bf36b901 AM	274	GFP_KERNEL, 0);
1da177e4 LT	275	}
1da177e4 LT	276
65f27f38	277	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	278
7d12e780	279	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	280	{
	281	schedule_work(&moom_work);
	282	}
	283	static struct sysrq_key_op sysrq_moom_op = {
	284	.handler = sysrq_handle_moom,
	285	.help_msg = "Full",
	286	.action_msg = "Manual OOM execution",
	287	};
	288
7d12e780	289	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	290	{
	291	send_sig_all(SIGKILL);
	292	console_loglevel = 8;
	293	}
	294	static struct sysrq_key_op sysrq_kill_op = {
	295	.handler = sysrq_handle_kill,
	296	.help_msg = "kIll",
	297	.action_msg = "Kill All Tasks",
	298	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	299	};
	300
7d12e780	301	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	302	{
	303	normalize_rt_tasks();
	304	}
	305	static struct sysrq_key_op sysrq_unrt_op = {
	306	.handler = sysrq_handle_unrt,
	307	.help_msg = "Nice",
	308	.action_msg = "Nice All RT Tasks",
	309	.enable_mask = SYSRQ_ENABLE_RTNICE,
	310	};
	311
	312	/* Key Operations table and lock */
	313	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	314
	315	static struct sysrq_key_op *sysrq_key_table[36] = {
	316	&sysrq_loglevel_op, /* 0 */
	317	&sysrq_loglevel_op, /* 1 */
	318	&sysrq_loglevel_op, /* 2 */
	319	&sysrq_loglevel_op, /* 3 */
	320	&sysrq_loglevel_op, /* 4 */
	321	&sysrq_loglevel_op, /* 5 */
	322	&sysrq_loglevel_op, /* 6 */
	323	&sysrq_loglevel_op, /* 7 */
	324	&sysrq_loglevel_op, /* 8 */
	325	&sysrq_loglevel_op, /* 9 */
	326
	327	/*
d346cce3 RD	328	* a: Don't use for system provided sysrqs, it is handled specially on
d346cce3 RD	329	* sparc and will never arrive.
bf36b901 AM	330	*/
	331	NULL, /* a */
	332	&sysrq_reboot_op, /* b */
d346cce3	333	&sysrq_crashdump_op, /* c & ibm_emac driver debug */
bf36b901 AM	334	&sysrq_showlocks_op, /* d */
	335	&sysrq_term_op, /* e */
	336	&sysrq_moom_op, /* f */
d346cce3	337	/* g: May be registered by ppc for kgdb */
bf36b901 AM	338	NULL, /* g */
	339	NULL, /* h */
	340	&sysrq_kill_op, /* i */
	341	NULL, /* j */
	342	&sysrq_SAK_op, /* k */
	343	NULL, /* l */
	344	&sysrq_showmem_op, /* m */
	345	&sysrq_unrt_op, /* n */
d346cce3	346	/* o: This will often be registered as 'Off' at init time */
bf36b901 AM	347	NULL, /* o */
bf36b901 AM	348	&sysrq_showregs_op, /* p */
88ad0bf6	349	&sysrq_show_timers_op, /* q */
d346cce3	350	&sysrq_unraw_op, /* r */
bf36b901 AM	351	&sysrq_sync_op, /* s */
	352	&sysrq_showstate_op, /* t */
	353	&sysrq_mountro_op, /* u */
d346cce3	354	/* v: May be registered at init time by SMP VOYAGER */
bf36b901	355	NULL, /* v */
d346cce3 RD	356	&sysrq_showstate_blocked_op, /* w */
	357	/* x: May be registered on ppc/powerpc for xmon */
	358	NULL, /* x */
bf36b901 AM	359	NULL, /* y */
bf36b901 AM	360	NULL /* z */
1da177e4 LT	361	};
	362
	363	/* key2index calculation, -1 on invalid index */
bf36b901 AM	364	static int sysrq_key_table_key2index(int key)
bf36b901 AM	365	{
1da177e4	366	int retval;
bf36b901 AM	367
bf36b901 AM	368	if ((key >= '0') && (key <= '9'))
1da177e4	369	retval = key - '0';
bf36b901	370	else if ((key >= 'a') && (key <= 'z'))
1da177e4	371	retval = key + 10 - 'a';
bf36b901	372	else
1da177e4	373	retval = -1;
1da177e4 LT	374	return retval;
	375	}
	376
	377	/*
	378	* get and put functions for the table, exposed to modules.
	379	*/
bf36b901 AM	380	struct sysrq_key_op *__sysrq_get_key_op(int key)
	381	{
	382	struct sysrq_key_op *op_p = NULL;
1da177e4	383	int i;
bf36b901	384
1da177e4	385	i = sysrq_key_table_key2index(key);
bf36b901 AM	386	if (i != -1)
bf36b901 AM	387	op_p = sysrq_key_table[i];
1da177e4 LT	388	return op_p;
	389	}
	390
bf36b901 AM	391	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	392	{
	393	int i = sysrq_key_table_key2index(key);
1da177e4	394
1da177e4 LT	395	if (i != -1)
	396	sysrq_key_table[i] = op_p;
	397	}
	398
	399	/*
bf36b901 AM	400	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	401	* by sysrq key handlers, as they are inside of the lock
1da177e4	402	*/
7d12e780	403	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	404	{
	405	struct sysrq_key_op *op_p;
	406	int orig_log_level;
bf36b901	407	int i;
1da177e4 LT	408	unsigned long flags;
	409
	410	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	411	orig_log_level = console_loglevel;
	412	console_loglevel = 7;
	413	printk(KERN_INFO "SysRq : ");
	414
	415	op_p = __sysrq_get_key_op(key);
	416	if (op_p) {
bf36b901 AM	417	/*
	418	* Should we check for enabled operations (/proc/sysrq-trigger
	419	* should not) and is the invoked operation enabled?
	420	*/
5d6f647f	421	if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
bf36b901	422	printk("%s\n", op_p->action_msg);
1da177e4	423	console_loglevel = orig_log_level;
7d12e780	424	op_p->handler(key, tty);
bf36b901	425	} else {
1da177e4	426	printk("This sysrq operation is disabled.\n");
bf36b901	427	}
1da177e4 LT	428	} else {
	429	printk("HELP : ");
	430	/* Only print the help msg once per handler */
bf36b901 AM	431	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	432	if (sysrq_key_table[i]) {
	433	int j;
	434
	435	for (j = 0; sysrq_key_table[i] !=
	436	sysrq_key_table[j]; j++)
	437	;
	438	if (j != i)
	439	continue;
	440	printk("%s ", sysrq_key_table[i]->help_msg);
	441	}
1da177e4	442	}
bf36b901	443	printk("\n");
1da177e4 LT	444	console_loglevel = orig_log_level;
	445	}
	446	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	447	}
	448
	449	/*
	450	* This function is called by the keyboard handler when SysRq is pressed
	451	* and any other keycode arrives.
	452	*/
7d12e780	453	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4	454	{
5d6f647f IM	455	if (sysrq_on())
5d6f647f IM	456	__handle_sysrq(key, tty, 1);
1da177e4	457	}
bf36b901	458	EXPORT_SYMBOL(handle_sysrq);
1da177e4	459
cf62ddce	460	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	461	struct sysrq_key_op *remove_op_p)
bf36b901 AM	462	{
1da177e4 LT	463
	464	int retval;
	465	unsigned long flags;
	466
	467	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	468	if (__sysrq_get_key_op(key) == remove_op_p) {
	469	__sysrq_put_key_op(key, insert_op_p);
	470	retval = 0;
	471	} else {
	472	retval = -1;
	473	}
	474	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	475	return retval;
	476	}
	477
	478	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	479	{
	480	return __sysrq_swap_key_ops(key, op_p, NULL);
	481	}
bf36b901	482	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	483
	484	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	485	{
	486	return __sysrq_swap_key_ops(key, NULL, op_p);
	487	}
1da177e4	488	EXPORT_SYMBOL(unregister_sysrq_key);