/* -*- 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 <linux/kexec.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 */
#ifdef CONFIG_KEXEC
/* crashdump sysrq handler */
static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
struct tty_struct *tty)
{
crash_kexec(pt_regs);
}
static struct sysrq_key_op sysrq_crashdump_op = {
.handler = sysrq_handle_crashdump,
.help_msg = "Crashdump",
.action_msg = "Trigger a crashdump",
.enable_mask = SYSRQ_ENABLE_DUMP,
};
#endif
/* reboot sysrq handler */
static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
struct tty_struct *tty)
{
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 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, 0);
}
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,
#ifdef CONFIG_KEXEC
/* c */ &sysrq_crashdump_op,
#else
/* c */ NULL,
#endif
/* 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);
