[mirror_ubuntu-bionic-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/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 <linux/oom.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 = default_utf8 ? VC_UNICODE : VC_XLATE;
}
static struct sysrq_key_op sysrq_unraw_op = {
	.handler	= sysrq_handle_unraw,
	.help_msg	= "unRaw",
	.action_msg	= "Keyboard mode set to system default",
	.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

#ifdef CONFIG_SMP
static DEFINE_SPINLOCK(show_lock);

static void showacpu(void *dummy)
{
	unsigned long flags;

	/* Idle CPUs have no interesting backtrace. */
	if (idle_cpu(smp_processor_id()))
		return;

	spin_lock_irqsave(&show_lock, flags);
	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	show_stack(NULL, NULL);
	spin_unlock_irqrestore(&show_lock, flags);
}

static void sysrq_showregs_othercpus(struct work_struct *dummy)
{
	smp_call_function(showacpu, NULL, 0);
}

static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);

static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
{
	struct pt_regs *regs = get_irq_regs();
	if (regs) {
		printk(KERN_INFO "CPU%d:\n", smp_processor_id());
		show_regs(regs);
	}
	schedule_work(&sysrq_showallcpus);
}

static struct sysrq_key_op sysrq_showallcpus_op = {
	.handler	= sysrq_handle_showallcpus,
	.help_msg	= "aLlcpus",
	.action_msg	= "Show backtrace of all active CPUs",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};
#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_global_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_zonelist(0, GFP_KERNEL), 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",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};

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 */
#ifdef CONFIG_SMP
	&sysrq_showallcpus_op,		/* l */
#else
	NULL,				/* l */
#endif
	&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 */
	/* y: May be registered on sparc64 for global register dump */
	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>
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>
5a3135c2	39	#include <linux/oom.h>
1da177e4 LT	40
1da177e4 LT	41	#include <asm/ptrace.h>
2033b0c3	42	#include <asm/irq_regs.h>
1da177e4 LT	43
1da177e4 LT	44	/* Whether we react on sysrq keys or just ignore them */
5d6f647f IM	45	int __read_mostly __sysrq_enabled = 1;
	46
	47	static int __read_mostly sysrq_always_enabled;
	48
	49	int sysrq_on(void)
	50	{
	51	return __sysrq_enabled \|\| sysrq_always_enabled;
	52	}
	53
	54	/*
	55	* A value of 1 means 'all', other nonzero values are an op mask:
	56	*/
	57	static inline int sysrq_on_mask(int mask)
	58	{
	59	return sysrq_always_enabled \|\| __sysrq_enabled == 1 \|\|
	60	(__sysrq_enabled & mask);
	61	}
	62
	63	static int __init sysrq_always_enabled_setup(char *str)
	64	{
	65	sysrq_always_enabled = 1;
	66	printk(KERN_INFO "debug: sysrq always enabled.\n");
	67
	68	return 1;
	69	}
	70
	71	__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
	72
1da177e4	73
7d12e780	74	static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
1da177e4 LT	75	{
	76	int i;
	77	i = key - '0';
	78	console_loglevel = 7;
	79	printk("Loglevel set to %d\n", i);
	80	console_loglevel = i;
bf36b901	81	}
1da177e4 LT	82	static struct sysrq_key_op sysrq_loglevel_op = {
	83	.handler = sysrq_handle_loglevel,
	84	.help_msg = "loglevel0-8",
	85	.action_msg = "Changing Loglevel",
	86	.enable_mask = SYSRQ_ENABLE_LOG,
	87	};
	88
1da177e4	89	#ifdef CONFIG_VT
7d12e780	90	static void sysrq_handle_SAK(int key, struct tty_struct *tty)
1da177e4	91	{
8b6312f4	92	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
8b6312f4	93	schedule_work(SAK_work);
1da177e4 LT	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)
2e8ecb9d	111	kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
1da177e4 LT	112	}
	113	static struct sysrq_key_op sysrq_unraw_op = {
	114	.handler = sysrq_handle_unraw,
	115	.help_msg = "unRaw",
2e8ecb9d	116	.action_msg = "Keyboard mode set to system default",
1da177e4 LT	117	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
1da177e4 LT	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
88ad0bf6 IM	162	static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
	163	{
	164	sysrq_timer_list_show();
	165	}
	166
	167	static struct sysrq_key_op sysrq_show_timers_op = {
	168	.handler = sysrq_handle_show_timers,
	169	.help_msg = "show-all-timers(Q)",
	170	.action_msg = "Show Pending Timers",
	171	};
	172
7d12e780	173	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	174	{
	175	emergency_remount();
	176	}
1da177e4 LT	177	static struct sysrq_key_op sysrq_mountro_op = {
	178	.handler = sysrq_handle_mountro,
	179	.help_msg = "Unmount",
	180	.action_msg = "Emergency Remount R/O",
	181	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	182	};
	183
8c64580d	184	#ifdef CONFIG_LOCKDEP
7d12e780	185	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	186	{
9a11b49a	187	debug_show_all_locks();
de5097c2	188	}
8c64580d	189
de5097c2 IM	190	static struct sysrq_key_op sysrq_showlocks_op = {
	191	.handler = sysrq_handle_showlocks,
	192	.help_msg = "show-all-locks(D)",
	193	.action_msg = "Show Locks Held",
	194	};
bf36b901 AM	195	#else
bf36b901 AM	196	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	197	#endif
1da177e4	198
5045bcae RR	199	#ifdef CONFIG_SMP
	200	static DEFINE_SPINLOCK(show_lock);
	201
	202	static void showacpu(void *dummy)
	203	{
	204	unsigned long flags;
	205
	206	/* Idle CPUs have no interesting backtrace. */
	207	if (idle_cpu(smp_processor_id()))
	208	return;
	209
	210	spin_lock_irqsave(&show_lock, flags);
	211	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	212	show_stack(NULL, NULL);
	213	spin_unlock_irqrestore(&show_lock, flags);
	214	}
	215
	216	static void sysrq_showregs_othercpus(struct work_struct *dummy)
	217	{
8b604d52	218	smp_call_function(showacpu, NULL, 0);
5045bcae RR	219	}
	220
	221	static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
	222
	223	static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
	224	{
	225	struct pt_regs *regs = get_irq_regs();
	226	if (regs) {
	227	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	228	show_regs(regs);
	229	}
	230	schedule_work(&sysrq_showallcpus);
	231	}
	232
	233	static struct sysrq_key_op sysrq_showallcpus_op = {
	234	.handler = sysrq_handle_showallcpus,
	235	.help_msg = "aLlcpus",
	236	.action_msg = "Show backtrace of all active CPUs",
	237	.enable_mask = SYSRQ_ENABLE_DUMP,
	238	};
	239	#endif
	240
7d12e780	241	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	242	{
7d12e780 DH	243	struct pt_regs *regs = get_irq_regs();
	244	if (regs)
	245	show_regs(regs);
1da177e4 LT	246	}
	247	static struct sysrq_key_op sysrq_showregs_op = {
	248	.handler = sysrq_handle_showregs,
	249	.help_msg = "showPc",
	250	.action_msg = "Show Regs",
	251	.enable_mask = SYSRQ_ENABLE_DUMP,
	252	};
	253
7d12e780	254	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	255	{
	256	show_state();
	257	}
	258	static struct sysrq_key_op sysrq_showstate_op = {
	259	.handler = sysrq_handle_showstate,
	260	.help_msg = "showTasks",
	261	.action_msg = "Show State",
	262	.enable_mask = SYSRQ_ENABLE_DUMP,
	263	};
	264
e59e2ae2 IM	265	static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
	266	{
	267	show_state_filter(TASK_UNINTERRUPTIBLE);
	268	}
	269	static struct sysrq_key_op sysrq_showstate_blocked_op = {
	270	.handler = sysrq_handle_showstate_blocked,
d346cce3	271	.help_msg = "shoW-blocked-tasks",
e59e2ae2 IM	272	.action_msg = "Show Blocked State",
	273	.enable_mask = SYSRQ_ENABLE_DUMP,
	274	};
	275
	276
7d12e780	277	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	278	{
	279	show_mem();
	280	}
	281	static struct sysrq_key_op sysrq_showmem_op = {
	282	.handler = sysrq_handle_showmem,
	283	.help_msg = "showMem",
	284	.action_msg = "Show Memory",
	285	.enable_mask = SYSRQ_ENABLE_DUMP,
	286	};
	287
bf36b901 AM	288	/*
	289	* Signal sysrq helper function. Sends a signal to all user processes.
	290	*/
1da177e4 LT	291	static void send_sig_all(int sig)
	292	{
	293	struct task_struct *p;
	294
	295	for_each_process(p) {
b460cbc5	296	if (p->mm && !is_global_init(p))
1da177e4 LT	297	/* Not swapper, init nor kernel thread */
	298	force_sig(sig, p);
	299	}
	300	}
	301
7d12e780	302	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	303	{
	304	send_sig_all(SIGTERM);
	305	console_loglevel = 8;
	306	}
	307	static struct sysrq_key_op sysrq_term_op = {
	308	.handler = sysrq_handle_term,
	309	.help_msg = "tErm",
	310	.action_msg = "Terminate All Tasks",
	311	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	312	};
	313
65f27f38	314	static void moom_callback(struct work_struct *ignored)
1da177e4	315	{
0e88460d	316	out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
1da177e4 LT	317	}
1da177e4 LT	318
65f27f38	319	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	320
7d12e780	321	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	322	{
	323	schedule_work(&moom_work);
	324	}
	325	static struct sysrq_key_op sysrq_moom_op = {
	326	.handler = sysrq_handle_moom,
	327	.help_msg = "Full",
	328	.action_msg = "Manual OOM execution",
b4236f81	329	.enable_mask = SYSRQ_ENABLE_SIGNAL,
1da177e4 LT	330	};
1da177e4 LT	331
7d12e780	332	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	333	{
	334	send_sig_all(SIGKILL);
	335	console_loglevel = 8;
	336	}
	337	static struct sysrq_key_op sysrq_kill_op = {
	338	.handler = sysrq_handle_kill,
	339	.help_msg = "kIll",
	340	.action_msg = "Kill All Tasks",
	341	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	342	};
	343
7d12e780	344	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	345	{
	346	normalize_rt_tasks();
	347	}
	348	static struct sysrq_key_op sysrq_unrt_op = {
	349	.handler = sysrq_handle_unrt,
	350	.help_msg = "Nice",
	351	.action_msg = "Nice All RT Tasks",
	352	.enable_mask = SYSRQ_ENABLE_RTNICE,
	353	};
	354
	355	/* Key Operations table and lock */
	356	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	357
	358	static struct sysrq_key_op *sysrq_key_table[36] = {
	359	&sysrq_loglevel_op, /* 0 */
	360	&sysrq_loglevel_op, /* 1 */
	361	&sysrq_loglevel_op, /* 2 */
	362	&sysrq_loglevel_op, /* 3 */
	363	&sysrq_loglevel_op, /* 4 */
	364	&sysrq_loglevel_op, /* 5 */
	365	&sysrq_loglevel_op, /* 6 */
	366	&sysrq_loglevel_op, /* 7 */
	367	&sysrq_loglevel_op, /* 8 */
	368	&sysrq_loglevel_op, /* 9 */
	369
	370	/*
d346cce3 RD	371	* a: Don't use for system provided sysrqs, it is handled specially on
d346cce3 RD	372	* sparc and will never arrive.
bf36b901 AM	373	*/
	374	NULL, /* a */
	375	&sysrq_reboot_op, /* b */
d346cce3	376	&sysrq_crashdump_op, /* c & ibm_emac driver debug */
bf36b901 AM	377	&sysrq_showlocks_op, /* d */
	378	&sysrq_term_op, /* e */
	379	&sysrq_moom_op, /* f */
d346cce3	380	/* g: May be registered by ppc for kgdb */
bf36b901 AM	381	NULL, /* g */
	382	NULL, /* h */
	383	&sysrq_kill_op, /* i */
	384	NULL, /* j */
	385	&sysrq_SAK_op, /* k */
5045bcae RR	386	#ifdef CONFIG_SMP
	387	&sysrq_showallcpus_op, /* l */
	388	#else
bf36b901	389	NULL, /* l */
5045bcae	390	#endif
bf36b901 AM	391	&sysrq_showmem_op, /* m */
bf36b901 AM	392	&sysrq_unrt_op, /* n */
d346cce3	393	/* o: This will often be registered as 'Off' at init time */
bf36b901 AM	394	NULL, /* o */
bf36b901 AM	395	&sysrq_showregs_op, /* p */
88ad0bf6	396	&sysrq_show_timers_op, /* q */
d346cce3	397	&sysrq_unraw_op, /* r */
bf36b901 AM	398	&sysrq_sync_op, /* s */
	399	&sysrq_showstate_op, /* t */
	400	&sysrq_mountro_op, /* u */
d346cce3	401	/* v: May be registered at init time by SMP VOYAGER */
bf36b901	402	NULL, /* v */
d346cce3 RD	403	&sysrq_showstate_blocked_op, /* w */
	404	/* x: May be registered on ppc/powerpc for xmon */
	405	NULL, /* x */
93dae5b7	406	/* y: May be registered on sparc64 for global register dump */
bf36b901 AM	407	NULL, /* y */
bf36b901 AM	408	NULL /* z */
1da177e4 LT	409	};
	410
	411	/* key2index calculation, -1 on invalid index */
bf36b901 AM	412	static int sysrq_key_table_key2index(int key)
bf36b901 AM	413	{
1da177e4	414	int retval;
bf36b901 AM	415
bf36b901 AM	416	if ((key >= '0') && (key <= '9'))
1da177e4	417	retval = key - '0';
bf36b901	418	else if ((key >= 'a') && (key <= 'z'))
1da177e4	419	retval = key + 10 - 'a';
bf36b901	420	else
1da177e4	421	retval = -1;
1da177e4 LT	422	return retval;
	423	}
	424
	425	/*
	426	* get and put functions for the table, exposed to modules.
	427	*/
bf36b901 AM	428	struct sysrq_key_op *__sysrq_get_key_op(int key)
	429	{
	430	struct sysrq_key_op *op_p = NULL;
1da177e4	431	int i;
bf36b901	432
1da177e4	433	i = sysrq_key_table_key2index(key);
bf36b901 AM	434	if (i != -1)
bf36b901 AM	435	op_p = sysrq_key_table[i];
1da177e4 LT	436	return op_p;
	437	}
	438
bf36b901 AM	439	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	440	{
	441	int i = sysrq_key_table_key2index(key);
1da177e4	442
1da177e4 LT	443	if (i != -1)
	444	sysrq_key_table[i] = op_p;
	445	}
	446
	447	/*
bf36b901 AM	448	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	449	* by sysrq key handlers, as they are inside of the lock
1da177e4	450	*/
7d12e780	451	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	452	{
	453	struct sysrq_key_op *op_p;
	454	int orig_log_level;
bf36b901	455	int i;
1da177e4 LT	456	unsigned long flags;
	457
	458	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	459	orig_log_level = console_loglevel;
	460	console_loglevel = 7;
	461	printk(KERN_INFO "SysRq : ");
	462
	463	op_p = __sysrq_get_key_op(key);
	464	if (op_p) {
bf36b901 AM	465	/*
	466	* Should we check for enabled operations (/proc/sysrq-trigger
	467	* should not) and is the invoked operation enabled?
	468	*/
5d6f647f	469	if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
bf36b901	470	printk("%s\n", op_p->action_msg);
1da177e4	471	console_loglevel = orig_log_level;
7d12e780	472	op_p->handler(key, tty);
bf36b901	473	} else {
1da177e4	474	printk("This sysrq operation is disabled.\n");
bf36b901	475	}
1da177e4 LT	476	} else {
	477	printk("HELP : ");
	478	/* Only print the help msg once per handler */
bf36b901 AM	479	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	480	if (sysrq_key_table[i]) {
	481	int j;
	482
	483	for (j = 0; sysrq_key_table[i] !=
	484	sysrq_key_table[j]; j++)
	485	;
	486	if (j != i)
	487	continue;
	488	printk("%s ", sysrq_key_table[i]->help_msg);
	489	}
1da177e4	490	}
bf36b901	491	printk("\n");
1da177e4 LT	492	console_loglevel = orig_log_level;
	493	}
	494	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	495	}
	496
	497	/*
	498	* This function is called by the keyboard handler when SysRq is pressed
	499	* and any other keycode arrives.
	500	*/
7d12e780	501	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4	502	{
5d6f647f IM	503	if (sysrq_on())
5d6f647f IM	504	__handle_sysrq(key, tty, 1);
1da177e4	505	}
bf36b901	506	EXPORT_SYMBOL(handle_sysrq);
1da177e4	507
cf62ddce	508	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	509	struct sysrq_key_op *remove_op_p)
bf36b901 AM	510	{
1da177e4 LT	511
	512	int retval;
	513	unsigned long flags;
	514
	515	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	516	if (__sysrq_get_key_op(key) == remove_op_p) {
	517	__sysrq_put_key_op(key, insert_op_p);
	518	retval = 0;
	519	} else {
	520	retval = -1;
	521	}
	522	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	523	return retval;
	524	}
	525
	526	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	527	{
	528	return __sysrq_swap_key_ops(key, op_p, NULL);
	529	}
bf36b901	530	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	531
	532	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	533	{
	534	return __sysrq_swap_key_ops(key, NULL, op_p);
	535	}
1da177e4	536	EXPORT_SYMBOL(unregister_sysrq_key);