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