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-rw-r--r--drivers/char/sysrq.c432
1 files changed, 432 insertions, 0 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
new file mode 100644
index 000000000000..f59f7cbd525b
--- /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);