1 files changed, 432 insertions, 0 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
new file mode 100644
index 00000000000..f59f7cbd525
--- /dev/null
+++ b/drivers/char/sysrq.c
@@ -0,0 +1,432 @@
+/* -*- 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/config.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/tty.h>
+#include <linux/mount.h>
+#include <linux/kdev_t.h>
+#include <linux/major.h>
+#include <linux/reboot.h>
+#include <linux/sysrq.h>
+#include <linux/kbd_kern.h>
+#include <linux/quotaops.h>
+#include <linux/smp_lock.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/suspend.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>		/* for fsync_bdev() */
+#include <linux/swap.h>
+#include <linux/spinlock.h>
+#include <linux/vt_kern.h>
+#include <linux/workqueue.h>
+
+#include <asm/ptrace.h>
+
+/* Whether we react on sysrq keys or just ignore them */
+int sysrq_enabled = 1;
+
+/* Loglevel sysrq handler */
+static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
+				  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,
+};
+
+
+/* SAK sysrq handler */
+#ifdef CONFIG_VT
+static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
+			     struct tty_struct *tty) 
+{
+	if (tty)
+		do_SAK(tty);
+	reset_vc(vc_cons[fg_console].d);
+}
+static struct sysrq_key_op sysrq_SAK_op = {
+	.handler	= sysrq_handle_SAK,
+	.help_msg	= "saK",
+	.action_msg	= "SAK",
+	.enable_mask	= SYSRQ_ENABLE_KEYBOARD,
+};
+#endif
+
+#ifdef CONFIG_VT
+/* unraw sysrq handler */
+static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
+			       struct tty_struct *tty) 
+{
+	struct kbd_struct *kbd = &kbd_table[fg_console];
+
+	if (kbd)
+		kbd->kbdmode = VC_XLATE;
+}
+static struct sysrq_key_op sysrq_unraw_op = {
+	.handler	= sysrq_handle_unraw,
+	.help_msg	= "unRaw",
+	.action_msg	= "Keyboard mode set to XLATE",
+	.enable_mask	= SYSRQ_ENABLE_KEYBOARD,
+};
+#endif /* CONFIG_VT */
+
+/* reboot sysrq handler */
+static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
+				struct tty_struct *tty) 
+{
+	local_irq_enable();
+	machine_restart(NULL);
+}
+
+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 pt_regs *pt_regs,
+			      struct tty_struct *tty) 
+{
+	emergency_sync();
+}
+
+static struct sysrq_key_op sysrq_sync_op = {
+	.handler	= sysrq_handle_sync,
+	.help_msg	= "Sync",
+	.action_msg	= "Emergency Sync",
+	.enable_mask	= SYSRQ_ENABLE_SYNC,
+};
+
+static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
+				 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,
+};
+
+/* END SYNC SYSRQ HANDLERS BLOCK */
+
+
+/* SHOW SYSRQ HANDLERS BLOCK */
+
+static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
+				  struct tty_struct *tty) 
+{
+	if (pt_regs)
+		show_regs(pt_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 pt_regs *pt_regs,
+				   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_showmem(int key, struct pt_regs *pt_regs,
+				 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,
+};
+
+/* SHOW SYSRQ HANDLERS BLOCK */
+
+
+/* SIGNAL SYSRQ HANDLERS BLOCK */
+
+/* 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 && p->pid != 1)
+			/* Not swapper, init nor kernel thread */
+			force_sig(sig, p);
+	}
+}
+
+static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
+			      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(void *ignored)
+{
+	out_of_memory(GFP_KERNEL);
+}
+
+static DECLARE_WORK(moom_work, moom_callback, NULL);
+
+static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
+			      struct tty_struct *tty)
+{
+	schedule_work(&moom_work);
+}
+static struct sysrq_key_op sysrq_moom_op = {
+	.handler	= sysrq_handle_moom,
+	.help_msg	= "Full",
+	.action_msg	= "Manual OOM execution",
+};
+
+static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
+			      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,
+};
+
+/* END SIGNAL SYSRQ HANDLERS BLOCK */
+
+static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
+				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);
+#define SYSRQ_KEY_TABLE_LENGTH 36
+static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = {
+/* 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 */	&sysrq_loglevel_op,
+/* a */	NULL, /* Don't use for system provided sysrqs,
+		 it is handled specially on the sparc
+		 and will never arrive */
+/* b */	&sysrq_reboot_op,
+/* c */ NULL,
+/* d */	NULL,
+/* e */	&sysrq_term_op,
+/* f */	&sysrq_moom_op,
+/* g */	NULL,
+/* h */	NULL,
+/* i */	&sysrq_kill_op,
+/* j */	NULL,
+#ifdef CONFIG_VT
+/* k */	&sysrq_SAK_op,
+#else
+/* k */	NULL,
+#endif
+/* l */	NULL,
+/* m */	&sysrq_showmem_op,
+/* n */	&sysrq_unrt_op,
+/* o */	NULL, /* This will often be registered
+		 as 'Off' at init time */
+/* p */	&sysrq_showregs_op,
+/* q */	NULL,
+#ifdef CONFIG_VT
+/* r */	&sysrq_unraw_op,
+#else
+/* r */ NULL,
+#endif
+/* s */	&sysrq_sync_op,
+/* t */	&sysrq_showstate_op,
+/* u */	&sysrq_mountro_op,
+/* v */	NULL, /* May be assigned at init time by SMP VOYAGER */
+/* w */	NULL,
+/* x */	NULL,
+/* y */	NULL,
+/* z */	NULL
+};
+
+/* 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;
+        int i;
+	
+	i = sysrq_key_table_key2index(key);
+        op_p = (i == -1) ? NULL : sysrq_key_table[i];
+        return op_p;
+}
+
+void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) {
+        int i;
+
+	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 pt_regs *pt_regs, struct tty_struct *tty, int check_mask)
+{
+	struct sysrq_key_op *op_p;
+	int orig_log_level;
+	int i, j;
+	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_enabled == 1 ||
+		    (sysrq_enabled & op_p->enable_mask)) {
+			printk ("%s\n", op_p->action_msg);
+			console_loglevel = orig_log_level;
+			op_p->handler(key, pt_regs, tty);
+		}
+		else
+			printk("This sysrq operation is disabled.\n");
+	} else {
+		printk("HELP : ");
+		/* Only print the help msg once per handler */
+		for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++) 
+		if (sysrq_key_table[i]) {
+			for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++);
+			if (j == i)
+				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 pt_regs *pt_regs, struct tty_struct *tty)
+{
+	if (!sysrq_enabled)
+		return;
+	__handle_sysrq(key, pt_regs, tty, 1);
+}
+
+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);
+}
+
+int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
+{
+	return __sysrq_swap_key_ops(key, NULL, op_p);
+}
+
+EXPORT_SYMBOL(handle_sysrq);
+EXPORT_SYMBOL(register_sysrq_key);
+EXPORT_SYMBOL(unregister_sysrq_key);