[GitHub/mt8127/android_kernel_alcatel_ttab.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/proc_fs.h>
#include <linux/nmi.h>
#include <linux/quotaops.h>
#include <linux/perf_event.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/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	= "loglevel(0-9)",
	.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 */

static void sysrq_handle_crash(int key, struct tty_struct *tty)
{
	char *killer = NULL;

	panic_on_oops = 1;	/* force panic */
	wmb();
	*killer = 1;
}
static struct sysrq_key_op sysrq_crash_op = {
	.handler	= sysrq_handle_crash,
	.help_msg	= "Crash",
	.action_msg	= "Trigger a crash",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};

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 clockevent devices & pending hrtimers (no others)",
};

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)
{
	/*
	 * Fall back to the workqueue based printing if the
	 * backtrace printing did not succeed or the
	 * architecture has no support for it:
	 */
	if (!trigger_all_cpu_backtrace()) {
		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	= "show-backtrace-all-active-cpus(L)",
	.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);
	perf_event_print_debug();
}
static struct sysrq_key_op sysrq_showregs_op = {
	.handler	= sysrq_handle_showregs,
	.help_msg	= "show-registers(P)",
	.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	= "show-task-states(T)",
	.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(W)",
	.action_msg	= "Show Blocked State",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};

#ifdef CONFIG_TRACING
#include <linux/ftrace.h>

static void sysrq_ftrace_dump(int key, struct tty_struct *tty)
{
	ftrace_dump();
}
static struct sysrq_key_op sysrq_ftrace_dump_op = {
	.handler	= sysrq_ftrace_dump,
	.help_msg	= "dump-ftrace-buffer(Z)",
	.action_msg	= "Dump ftrace buffer",
	.enable_mask	= SYSRQ_ENABLE_DUMP,
};
#else
#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)0)
#endif

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	= "show-memory-usage(M)",
	.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	= "terminate-all-tasks(E)",
	.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	= "memory-full-oom-kill(F)",
	.action_msg	= "Manual OOM execution",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};

#ifdef CONFIG_BLOCK
static void sysrq_handle_thaw(int key, struct tty_struct *tty)
{
	emergency_thaw_all();
}
static struct sysrq_key_op sysrq_thaw_op = {
	.handler	= sysrq_handle_thaw,
	.help_msg	= "thaw-filesystems(J)",
	.action_msg	= "Emergency Thaw of all frozen filesystems",
	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
};
#endif

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-all-tasks(I)",
	.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-all-RT-tasks(N)",
	.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_crash_op,		/* c & ibm_emac driver debug */
	&sysrq_showlocks_op,		/* d */
	&sysrq_term_op,			/* e */
	&sysrq_moom_op,			/* f */
	/* g: May be registered for the kernel debugger */
	NULL,				/* g */
	NULL,				/* h - reserved for help */
	&sysrq_kill_op,			/* i */
#ifdef CONFIG_BLOCK
	&sysrq_thaw_op,			/* j */
#else
	NULL,				/* j */
#endif
	&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 for frame buffer console restore */
	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 */
	&sysrq_ftrace_dump_op,		/* 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);
	/*
	 * Raise the apparent loglevel to maximum so that the sysrq header
	 * is shown to provide the user with positive feedback.  We do not
	 * simply emit this at KERN_EMERG as that would change message
	 * routing in the consumers of /proc/kmsg.
	 */
	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);

#ifdef CONFIG_PROC_FS
/*
 * writing 'C' to /proc/sysrq-trigger is like sysrq-C
 */
static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
				   size_t count, loff_t *ppos)
{
	if (count) {
		char c;

		if (get_user(c, buf))
			return -EFAULT;
		__handle_sysrq(c, NULL, 0);
	}
	return count;
}

static const struct file_operations proc_sysrq_trigger_operations = {
	.write		= write_sysrq_trigger,
};

static int __init sysrq_init(void)
{
	proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
	return 0;
}
module_init(sysrq_init);
#endif
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>
f40cbaa5	26	#include <linux/proc_fs.h>
c1dc0b9c	27	#include <linux/nmi.h>
1da177e4	28	#include <linux/quotaops.h>
cdd6c482	29	#include <linux/perf_event.h>
1da177e4 LT	30	#include <linux/kernel.h>
	31	#include <linux/module.h>
	32	#include <linux/suspend.h>
	33	#include <linux/writeback.h>
	34	#include <linux/buffer_head.h> /* for fsync_bdev() */
	35	#include <linux/swap.h>
	36	#include <linux/spinlock.h>
	37	#include <linux/vt_kern.h>
	38	#include <linux/workqueue.h>
88ad0bf6	39	#include <linux/hrtimer.h>
5a3135c2	40	#include <linux/oom.h>
1da177e4 LT	41
1da177e4 LT	42	#include <asm/ptrace.h>
2033b0c3	43	#include <asm/irq_regs.h>
1da177e4 LT	44
1da177e4 LT	45	/* Whether we react on sysrq keys or just ignore them */
5d6f647f IM	46	int __read_mostly __sysrq_enabled = 1;
	47
	48	static int __read_mostly sysrq_always_enabled;
	49
	50	int sysrq_on(void)
	51	{
	52	return __sysrq_enabled \|\| sysrq_always_enabled;
	53	}
	54
	55	/*
	56	* A value of 1 means 'all', other nonzero values are an op mask:
	57	*/
	58	static inline int sysrq_on_mask(int mask)
	59	{
	60	return sysrq_always_enabled \|\| __sysrq_enabled == 1 \|\|
	61	(__sysrq_enabled & mask);
	62	}
	63
	64	static int __init sysrq_always_enabled_setup(char *str)
	65	{
	66	sysrq_always_enabled = 1;
	67	printk(KERN_INFO "debug: sysrq always enabled.\n");
	68
	69	return 1;
	70	}
	71
	72	__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
	73
1da177e4	74
7d12e780	75	static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
1da177e4 LT	76	{
	77	int i;
	78	i = key - '0';
	79	console_loglevel = 7;
	80	printk("Loglevel set to %d\n", i);
	81	console_loglevel = i;
bf36b901	82	}
1da177e4 LT	83	static struct sysrq_key_op sysrq_loglevel_op = {
1da177e4 LT	84	.handler = sysrq_handle_loglevel,
208b95ce	85	.help_msg = "loglevel(0-9)",
1da177e4 LT	86	.action_msg = "Changing Loglevel",
	87	.enable_mask = SYSRQ_ENABLE_LOG,
	88	};
	89
1da177e4	90	#ifdef CONFIG_VT
7d12e780	91	static void sysrq_handle_SAK(int key, struct tty_struct *tty)
1da177e4	92	{
8b6312f4	93	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
8b6312f4	94	schedule_work(SAK_work);
1da177e4 LT	95	}
	96	static struct sysrq_key_op sysrq_SAK_op = {
	97	.handler = sysrq_handle_SAK,
	98	.help_msg = "saK",
	99	.action_msg = "SAK",
	100	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
	101	};
bf36b901 AM	102	#else
bf36b901 AM	103	#define sysrq_SAK_op ((struct sysrq_key_op )0)
1da177e4 LT	104	#endif
	105
	106	#ifdef CONFIG_VT
7d12e780	107	static void sysrq_handle_unraw(int key, struct tty_struct *tty)
1da177e4 LT	108	{
	109	struct kbd_struct *kbd = &kbd_table[fg_console];
	110
	111	if (kbd)
2e8ecb9d	112	kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
1da177e4 LT	113	}
	114	static struct sysrq_key_op sysrq_unraw_op = {
	115	.handler = sysrq_handle_unraw,
	116	.help_msg = "unRaw",
2e8ecb9d	117	.action_msg = "Keyboard mode set to system default",
1da177e4 LT	118	.enable_mask = SYSRQ_ENABLE_KEYBOARD,
1da177e4 LT	119	};
bf36b901 AM	120	#else
bf36b901 AM	121	#define sysrq_unraw_op ((struct sysrq_key_op )0)
1da177e4 LT	122	#endif /* CONFIG_VT */
1da177e4 LT	123
d6580a9f	124	static void sysrq_handle_crash(int key, struct tty_struct *tty)
86b1ae38	125	{
d6580a9f	126	char *killer = NULL;
cab8bd34 HS	127
	128	panic_on_oops = 1; /* force panic */
	129	wmb();
d6580a9f	130	*killer = 1;
86b1ae38	131	}
cab8bd34	132	static struct sysrq_key_op sysrq_crash_op = {
d6580a9f NH	133	.handler = sysrq_handle_crash,
	134	.help_msg = "Crash",
	135	.action_msg = "Trigger a crash",
86b1ae38 HN	136	.enable_mask = SYSRQ_ENABLE_DUMP,
86b1ae38 HN	137	};
86b1ae38	138
7d12e780	139	static void sysrq_handle_reboot(int key, struct tty_struct *tty)
1da177e4	140	{
b2e9c7d0	141	lockdep_off();
1da177e4	142	local_irq_enable();
4de8b9b7	143	emergency_restart();
1da177e4	144	}
1da177e4 LT	145	static struct sysrq_key_op sysrq_reboot_op = {
	146	.handler = sysrq_handle_reboot,
	147	.help_msg = "reBoot",
	148	.action_msg = "Resetting",
	149	.enable_mask = SYSRQ_ENABLE_BOOT,
	150	};
	151
7d12e780	152	static void sysrq_handle_sync(int key, struct tty_struct *tty)
1da177e4 LT	153	{
	154	emergency_sync();
	155	}
1da177e4 LT	156	static struct sysrq_key_op sysrq_sync_op = {
	157	.handler = sysrq_handle_sync,
	158	.help_msg = "Sync",
	159	.action_msg = "Emergency Sync",
	160	.enable_mask = SYSRQ_ENABLE_SYNC,
	161	};
	162
88ad0bf6 IM	163	static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
	164	{
	165	sysrq_timer_list_show();
	166	}
	167
	168	static struct sysrq_key_op sysrq_show_timers_op = {
	169	.handler = sysrq_handle_show_timers,
	170	.help_msg = "show-all-timers(Q)",
322acf65	171	.action_msg = "Show clockevent devices & pending hrtimers (no others)",
88ad0bf6 IM	172	};
88ad0bf6 IM	173
7d12e780	174	static void sysrq_handle_mountro(int key, struct tty_struct *tty)
1da177e4 LT	175	{
	176	emergency_remount();
	177	}
1da177e4 LT	178	static struct sysrq_key_op sysrq_mountro_op = {
	179	.handler = sysrq_handle_mountro,
	180	.help_msg = "Unmount",
	181	.action_msg = "Emergency Remount R/O",
	182	.enable_mask = SYSRQ_ENABLE_REMOUNT,
	183	};
	184
8c64580d	185	#ifdef CONFIG_LOCKDEP
7d12e780	186	static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
de5097c2	187	{
9a11b49a	188	debug_show_all_locks();
de5097c2	189	}
8c64580d	190
de5097c2 IM	191	static struct sysrq_key_op sysrq_showlocks_op = {
	192	.handler = sysrq_handle_showlocks,
	193	.help_msg = "show-all-locks(D)",
	194	.action_msg = "Show Locks Held",
	195	};
bf36b901 AM	196	#else
bf36b901 AM	197	#define sysrq_showlocks_op ((struct sysrq_key_op )0)
de5097c2	198	#endif
1da177e4	199
5045bcae RR	200	#ifdef CONFIG_SMP
	201	static DEFINE_SPINLOCK(show_lock);
	202
	203	static void showacpu(void *dummy)
	204	{
	205	unsigned long flags;
	206
	207	/* Idle CPUs have no interesting backtrace. */
	208	if (idle_cpu(smp_processor_id()))
	209	return;
	210
	211	spin_lock_irqsave(&show_lock, flags);
	212	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	213	show_stack(NULL, NULL);
	214	spin_unlock_irqrestore(&show_lock, flags);
	215	}
	216
	217	static void sysrq_showregs_othercpus(struct work_struct *dummy)
	218	{
8b604d52	219	smp_call_function(showacpu, NULL, 0);
5045bcae RR	220	}
	221
	222	static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
	223
	224	static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
	225	{
47cab6a7 IM	226	/*
	227	* Fall back to the workqueue based printing if the
	228	* backtrace printing did not succeed or the
	229	* architecture has no support for it:
	230	*/
	231	if (!trigger_all_cpu_backtrace()) {
	232	struct pt_regs *regs = get_irq_regs();
	233
	234	if (regs) {
	235	printk(KERN_INFO "CPU%d:\n", smp_processor_id());
	236	show_regs(regs);
	237	}
	238	schedule_work(&sysrq_showallcpus);
	239	}
5045bcae RR	240	}
	241
	242	static struct sysrq_key_op sysrq_showallcpus_op = {
	243	.handler = sysrq_handle_showallcpus,
208b95ce	244	.help_msg = "show-backtrace-all-active-cpus(L)",
5045bcae RR	245	.action_msg = "Show backtrace of all active CPUs",
	246	.enable_mask = SYSRQ_ENABLE_DUMP,
	247	};
	248	#endif
	249
7d12e780	250	static void sysrq_handle_showregs(int key, struct tty_struct *tty)
1da177e4	251	{
7d12e780 DH	252	struct pt_regs *regs = get_irq_regs();
	253	if (regs)
	254	show_regs(regs);
cdd6c482	255	perf_event_print_debug();
1da177e4 LT	256	}
	257	static struct sysrq_key_op sysrq_showregs_op = {
	258	.handler = sysrq_handle_showregs,
208b95ce	259	.help_msg = "show-registers(P)",
1da177e4 LT	260	.action_msg = "Show Regs",
	261	.enable_mask = SYSRQ_ENABLE_DUMP,
	262	};
	263
7d12e780	264	static void sysrq_handle_showstate(int key, struct tty_struct *tty)
1da177e4 LT	265	{
	266	show_state();
	267	}
	268	static struct sysrq_key_op sysrq_showstate_op = {
	269	.handler = sysrq_handle_showstate,
208b95ce	270	.help_msg = "show-task-states(T)",
1da177e4 LT	271	.action_msg = "Show State",
	272	.enable_mask = SYSRQ_ENABLE_DUMP,
	273	};
	274
e59e2ae2 IM	275	static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
	276	{
	277	show_state_filter(TASK_UNINTERRUPTIBLE);
	278	}
	279	static struct sysrq_key_op sysrq_showstate_blocked_op = {
	280	.handler = sysrq_handle_showstate_blocked,
208b95ce	281	.help_msg = "show-blocked-tasks(W)",
e59e2ae2 IM	282	.action_msg = "Show Blocked State",
	283	.enable_mask = SYSRQ_ENABLE_DUMP,
	284	};
	285
69f698ad PZ	286	#ifdef CONFIG_TRACING
	287	#include <linux/ftrace.h>
	288
	289	static void sysrq_ftrace_dump(int key, struct tty_struct *tty)
	290	{
	291	ftrace_dump();
	292	}
	293	static struct sysrq_key_op sysrq_ftrace_dump_op = {
	294	.handler = sysrq_ftrace_dump,
3871f2ff	295	.help_msg = "dump-ftrace-buffer(Z)",
69f698ad PZ	296	.action_msg = "Dump ftrace buffer",
	297	.enable_mask = SYSRQ_ENABLE_DUMP,
	298	};
	299	#else
	300	#define sysrq_ftrace_dump_op ((struct sysrq_key_op )0)
	301	#endif
e59e2ae2	302
7d12e780	303	static void sysrq_handle_showmem(int key, struct tty_struct *tty)
1da177e4 LT	304	{
	305	show_mem();
	306	}
	307	static struct sysrq_key_op sysrq_showmem_op = {
	308	.handler = sysrq_handle_showmem,
208b95ce	309	.help_msg = "show-memory-usage(M)",
1da177e4 LT	310	.action_msg = "Show Memory",
	311	.enable_mask = SYSRQ_ENABLE_DUMP,
	312	};
	313
bf36b901 AM	314	/*
	315	* Signal sysrq helper function. Sends a signal to all user processes.
	316	*/
1da177e4 LT	317	static void send_sig_all(int sig)
	318	{
	319	struct task_struct *p;
	320
	321	for_each_process(p) {
b460cbc5	322	if (p->mm && !is_global_init(p))
1da177e4 LT	323	/* Not swapper, init nor kernel thread */
	324	force_sig(sig, p);
	325	}
	326	}
	327
7d12e780	328	static void sysrq_handle_term(int key, struct tty_struct *tty)
1da177e4 LT	329	{
	330	send_sig_all(SIGTERM);
	331	console_loglevel = 8;
	332	}
	333	static struct sysrq_key_op sysrq_term_op = {
	334	.handler = sysrq_handle_term,
208b95ce	335	.help_msg = "terminate-all-tasks(E)",
1da177e4 LT	336	.action_msg = "Terminate All Tasks",
	337	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	338	};
	339
65f27f38	340	static void moom_callback(struct work_struct *ignored)
1da177e4	341	{
0e88460d	342	out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
1da177e4 LT	343	}
1da177e4 LT	344
65f27f38	345	static DECLARE_WORK(moom_work, moom_callback);
1da177e4	346
7d12e780	347	static void sysrq_handle_moom(int key, struct tty_struct *tty)
1da177e4 LT	348	{
	349	schedule_work(&moom_work);
	350	}
	351	static struct sysrq_key_op sysrq_moom_op = {
	352	.handler = sysrq_handle_moom,
208b95ce	353	.help_msg = "memory-full-oom-kill(F)",
1da177e4	354	.action_msg = "Manual OOM execution",
b4236f81	355	.enable_mask = SYSRQ_ENABLE_SIGNAL,
1da177e4 LT	356	};
1da177e4 LT	357
c2d75438 ES	358	#ifdef CONFIG_BLOCK
	359	static void sysrq_handle_thaw(int key, struct tty_struct *tty)
	360	{
	361	emergency_thaw_all();
	362	}
	363	static struct sysrq_key_op sysrq_thaw_op = {
	364	.handler = sysrq_handle_thaw,
	365	.help_msg = "thaw-filesystems(J)",
	366	.action_msg = "Emergency Thaw of all frozen filesystems",
	367	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	368	};
	369	#endif
	370
7d12e780	371	static void sysrq_handle_kill(int key, struct tty_struct *tty)
1da177e4 LT	372	{
	373	send_sig_all(SIGKILL);
	374	console_loglevel = 8;
	375	}
	376	static struct sysrq_key_op sysrq_kill_op = {
	377	.handler = sysrq_handle_kill,
208b95ce	378	.help_msg = "kill-all-tasks(I)",
1da177e4 LT	379	.action_msg = "Kill All Tasks",
	380	.enable_mask = SYSRQ_ENABLE_SIGNAL,
	381	};
	382
7d12e780	383	static void sysrq_handle_unrt(int key, struct tty_struct *tty)
1da177e4 LT	384	{
	385	normalize_rt_tasks();
	386	}
	387	static struct sysrq_key_op sysrq_unrt_op = {
	388	.handler = sysrq_handle_unrt,
208b95ce	389	.help_msg = "nice-all-RT-tasks(N)",
1da177e4 LT	390	.action_msg = "Nice All RT Tasks",
	391	.enable_mask = SYSRQ_ENABLE_RTNICE,
	392	};
	393
	394	/* Key Operations table and lock */
	395	static DEFINE_SPINLOCK(sysrq_key_table_lock);
bf36b901 AM	396
	397	static struct sysrq_key_op *sysrq_key_table[36] = {
	398	&sysrq_loglevel_op, /* 0 */
	399	&sysrq_loglevel_op, /* 1 */
	400	&sysrq_loglevel_op, /* 2 */
	401	&sysrq_loglevel_op, /* 3 */
	402	&sysrq_loglevel_op, /* 4 */
	403	&sysrq_loglevel_op, /* 5 */
	404	&sysrq_loglevel_op, /* 6 */
	405	&sysrq_loglevel_op, /* 7 */
	406	&sysrq_loglevel_op, /* 8 */
	407	&sysrq_loglevel_op, /* 9 */
	408
	409	/*
d346cce3 RD	410	* a: Don't use for system provided sysrqs, it is handled specially on
d346cce3 RD	411	* sparc and will never arrive.
bf36b901 AM	412	*/
	413	NULL, /* a */
	414	&sysrq_reboot_op, /* b */
cab8bd34	415	&sysrq_crash_op, /* c & ibm_emac driver debug */
bf36b901 AM	416	&sysrq_showlocks_op, /* d */
	417	&sysrq_term_op, /* e */
	418	&sysrq_moom_op, /* f */
364b5b7b	419	/* g: May be registered for the kernel debugger */
bf36b901	420	NULL, /* g */
c2d75438	421	NULL, /* h - reserved for help */
bf36b901	422	&sysrq_kill_op, /* i */
c2d75438 ES	423	#ifdef CONFIG_BLOCK
	424	&sysrq_thaw_op, /* j */
	425	#else
bf36b901	426	NULL, /* j */
c2d75438	427	#endif
bf36b901	428	&sysrq_SAK_op, /* k */
5045bcae RR	429	#ifdef CONFIG_SMP
	430	&sysrq_showallcpus_op, /* l */
	431	#else
bf36b901	432	NULL, /* l */
5045bcae	433	#endif
bf36b901 AM	434	&sysrq_showmem_op, /* m */
bf36b901 AM	435	&sysrq_unrt_op, /* n */
d346cce3	436	/* o: This will often be registered as 'Off' at init time */
bf36b901 AM	437	NULL, /* o */
bf36b901 AM	438	&sysrq_showregs_op, /* p */
88ad0bf6	439	&sysrq_show_timers_op, /* q */
d346cce3	440	&sysrq_unraw_op, /* r */
bf36b901 AM	441	&sysrq_sync_op, /* s */
	442	&sysrq_showstate_op, /* t */
	443	&sysrq_mountro_op, /* u */
364b5b7b	444	/* v: May be registered for frame buffer console restore */
bf36b901	445	NULL, /* v */
d346cce3 RD	446	&sysrq_showstate_blocked_op, /* w */
	447	/* x: May be registered on ppc/powerpc for xmon */
	448	NULL, /* x */
93dae5b7	449	/* y: May be registered on sparc64 for global register dump */
bf36b901	450	NULL, /* y */
69f698ad	451	&sysrq_ftrace_dump_op, /* z */
1da177e4 LT	452	};
	453
	454	/* key2index calculation, -1 on invalid index */
bf36b901 AM	455	static int sysrq_key_table_key2index(int key)
bf36b901 AM	456	{
1da177e4	457	int retval;
bf36b901 AM	458
bf36b901 AM	459	if ((key >= '0') && (key <= '9'))
1da177e4	460	retval = key - '0';
bf36b901	461	else if ((key >= 'a') && (key <= 'z'))
1da177e4	462	retval = key + 10 - 'a';
bf36b901	463	else
1da177e4	464	retval = -1;
1da177e4 LT	465	return retval;
	466	}
	467
	468	/*
	469	* get and put functions for the table, exposed to modules.
	470	*/
bf36b901 AM	471	struct sysrq_key_op *__sysrq_get_key_op(int key)
	472	{
	473	struct sysrq_key_op *op_p = NULL;
1da177e4	474	int i;
bf36b901	475
1da177e4	476	i = sysrq_key_table_key2index(key);
bf36b901 AM	477	if (i != -1)
bf36b901 AM	478	op_p = sysrq_key_table[i];
1da177e4 LT	479	return op_p;
	480	}
	481
bf36b901 AM	482	static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
	483	{
	484	int i = sysrq_key_table_key2index(key);
1da177e4	485
1da177e4 LT	486	if (i != -1)
	487	sysrq_key_table[i] = op_p;
	488	}
	489
	490	/*
bf36b901 AM	491	* This is the non-locking version of handle_sysrq. It must/can only be called
bf36b901 AM	492	* by sysrq key handlers, as they are inside of the lock
1da177e4	493	*/
7d12e780	494	void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
1da177e4 LT	495	{
	496	struct sysrq_key_op *op_p;
	497	int orig_log_level;
bf36b901	498	int i;
1da177e4 LT	499	unsigned long flags;
	500
	501	spin_lock_irqsave(&sysrq_key_table_lock, flags);
fb144adc AW	502	/*
	503	* Raise the apparent loglevel to maximum so that the sysrq header
	504	* is shown to provide the user with positive feedback. We do not
	505	* simply emit this at KERN_EMERG as that would change message
	506	* routing in the consumers of /proc/kmsg.
	507	*/
1da177e4 LT	508	orig_log_level = console_loglevel;
	509	console_loglevel = 7;
	510	printk(KERN_INFO "SysRq : ");
	511
	512	op_p = __sysrq_get_key_op(key);
	513	if (op_p) {
bf36b901 AM	514	/*
	515	* Should we check for enabled operations (/proc/sysrq-trigger
	516	* should not) and is the invoked operation enabled?
	517	*/
5d6f647f	518	if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
bf36b901	519	printk("%s\n", op_p->action_msg);
1da177e4	520	console_loglevel = orig_log_level;
7d12e780	521	op_p->handler(key, tty);
bf36b901	522	} else {
1da177e4	523	printk("This sysrq operation is disabled.\n");
bf36b901	524	}
1da177e4 LT	525	} else {
	526	printk("HELP : ");
	527	/* Only print the help msg once per handler */
bf36b901 AM	528	for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
	529	if (sysrq_key_table[i]) {
	530	int j;
	531
	532	for (j = 0; sysrq_key_table[i] !=
	533	sysrq_key_table[j]; j++)
	534	;
	535	if (j != i)
	536	continue;
	537	printk("%s ", sysrq_key_table[i]->help_msg);
	538	}
1da177e4	539	}
bf36b901	540	printk("\n");
1da177e4 LT	541	console_loglevel = orig_log_level;
	542	}
	543	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
	544	}
	545
	546	/*
	547	* This function is called by the keyboard handler when SysRq is pressed
	548	* and any other keycode arrives.
	549	*/
7d12e780	550	void handle_sysrq(int key, struct tty_struct *tty)
1da177e4	551	{
5d6f647f IM	552	if (sysrq_on())
5d6f647f IM	553	__handle_sysrq(key, tty, 1);
1da177e4	554	}
bf36b901	555	EXPORT_SYMBOL(handle_sysrq);
1da177e4	556
cf62ddce	557	static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
bf36b901 AM	558	struct sysrq_key_op *remove_op_p)
bf36b901 AM	559	{
1da177e4 LT	560
	561	int retval;
	562	unsigned long flags;
	563
	564	spin_lock_irqsave(&sysrq_key_table_lock, flags);
	565	if (__sysrq_get_key_op(key) == remove_op_p) {
	566	__sysrq_put_key_op(key, insert_op_p);
	567	retval = 0;
	568	} else {
	569	retval = -1;
	570	}
	571	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
1da177e4 LT	572	return retval;
	573	}
	574
	575	int register_sysrq_key(int key, struct sysrq_key_op *op_p)
	576	{
	577	return __sysrq_swap_key_ops(key, op_p, NULL);
	578	}
bf36b901	579	EXPORT_SYMBOL(register_sysrq_key);
1da177e4 LT	580
	581	int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
	582	{
	583	return __sysrq_swap_key_ops(key, NULL, op_p);
	584	}
1da177e4	585	EXPORT_SYMBOL(unregister_sysrq_key);
f40cbaa5 AD	586
	587	#ifdef CONFIG_PROC_FS
	588	/*
	589	* writing 'C' to /proc/sysrq-trigger is like sysrq-C
	590	*/
	591	static ssize_t write_sysrq_trigger(struct file file, const char __user buf,
	592	size_t count, loff_t *ppos)
	593	{
	594	if (count) {
	595	char c;
	596
	597	if (get_user(c, buf))
	598	return -EFAULT;
	599	__handle_sysrq(c, NULL, 0);
	600	}
	601	return count;
	602	}
	603
	604	static const struct file_operations proc_sysrq_trigger_operations = {
	605	.write = write_sysrq_trigger,
	606	};
	607
	608	static int __init sysrq_init(void)
	609	{
	610	proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
	611	return 0;
	612	}
	613	module_init(sysrq_init);
	614	#endif