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);