452 lines
11 KiB
C
452 lines
11 KiB
C
/* -*- linux-c -*-
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*
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* $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
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*
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* Linux Magic System Request Key Hacks
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*
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* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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* based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
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*
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* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
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* overhauled to use key registration
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* based upon discusions in irc://irc.openprojects.net/#kernelnewbies
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*/
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/tty.h>
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#include <linux/mount.h>
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#include <linux/kdev_t.h>
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#include <linux/major.h>
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#include <linux/reboot.h>
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#include <linux/sysrq.h>
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#include <linux/kbd_kern.h>
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#include <linux/quotaops.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/suspend.h>
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#include <linux/writeback.h>
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#include <linux/buffer_head.h> /* for fsync_bdev() */
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#include <linux/swap.h>
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#include <linux/spinlock.h>
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#include <linux/vt_kern.h>
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#include <linux/workqueue.h>
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#include <linux/kexec.h>
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#include <asm/ptrace.h>
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/* Whether we react on sysrq keys or just ignore them */
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int sysrq_enabled = 1;
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static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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int i;
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i = key - '0';
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console_loglevel = 7;
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printk("Loglevel set to %d\n", i);
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console_loglevel = i;
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}
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static struct sysrq_key_op sysrq_loglevel_op = {
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.handler = sysrq_handle_loglevel,
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.help_msg = "loglevel0-8",
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.action_msg = "Changing Loglevel",
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.enable_mask = SYSRQ_ENABLE_LOG,
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};
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#ifdef CONFIG_VT
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static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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if (tty)
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do_SAK(tty);
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reset_vc(vc_cons[fg_console].d);
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}
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static struct sysrq_key_op sysrq_SAK_op = {
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.handler = sysrq_handle_SAK,
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.help_msg = "saK",
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.action_msg = "SAK",
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.enable_mask = SYSRQ_ENABLE_KEYBOARD,
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};
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#else
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#define sysrq_SAK_op (*(struct sysrq_key_op *)0)
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#endif
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#ifdef CONFIG_VT
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static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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struct kbd_struct *kbd = &kbd_table[fg_console];
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if (kbd)
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kbd->kbdmode = VC_XLATE;
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}
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static struct sysrq_key_op sysrq_unraw_op = {
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.handler = sysrq_handle_unraw,
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.help_msg = "unRaw",
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.action_msg = "Keyboard mode set to XLATE",
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.enable_mask = SYSRQ_ENABLE_KEYBOARD,
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};
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#else
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#define sysrq_unraw_op (*(struct sysrq_key_op *)0)
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#endif /* CONFIG_VT */
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#ifdef CONFIG_KEXEC
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static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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crash_kexec(pt_regs);
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}
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static struct sysrq_key_op sysrq_crashdump_op = {
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.handler = sysrq_handle_crashdump,
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.help_msg = "Crashdump",
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.action_msg = "Trigger a crashdump",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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#else
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#define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
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#endif
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static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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local_irq_enable();
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emergency_restart();
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}
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static struct sysrq_key_op sysrq_reboot_op = {
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.handler = sysrq_handle_reboot,
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.help_msg = "reBoot",
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.action_msg = "Resetting",
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.enable_mask = SYSRQ_ENABLE_BOOT,
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};
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static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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emergency_sync();
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}
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static struct sysrq_key_op sysrq_sync_op = {
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.handler = sysrq_handle_sync,
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.help_msg = "Sync",
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.action_msg = "Emergency Sync",
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.enable_mask = SYSRQ_ENABLE_SYNC,
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};
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static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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emergency_remount();
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}
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static struct sysrq_key_op sysrq_mountro_op = {
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.handler = sysrq_handle_mountro,
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.help_msg = "Unmount",
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.action_msg = "Emergency Remount R/O",
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.enable_mask = SYSRQ_ENABLE_REMOUNT,
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};
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#ifdef CONFIG_LOCKDEP
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static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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debug_show_all_locks();
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}
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static struct sysrq_key_op sysrq_showlocks_op = {
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.handler = sysrq_handle_showlocks,
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.help_msg = "show-all-locks(D)",
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.action_msg = "Show Locks Held",
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};
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#else
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#define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
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#endif
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static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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if (pt_regs)
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show_regs(pt_regs);
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}
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static struct sysrq_key_op sysrq_showregs_op = {
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.handler = sysrq_handle_showregs,
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.help_msg = "showPc",
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.action_msg = "Show Regs",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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show_state();
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}
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static struct sysrq_key_op sysrq_showstate_op = {
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.handler = sysrq_handle_showstate,
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.help_msg = "showTasks",
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.action_msg = "Show State",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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show_mem();
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}
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static struct sysrq_key_op sysrq_showmem_op = {
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.handler = sysrq_handle_showmem,
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.help_msg = "showMem",
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.action_msg = "Show Memory",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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/*
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* Signal sysrq helper function. Sends a signal to all user processes.
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*/
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static void send_sig_all(int sig)
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{
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struct task_struct *p;
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for_each_process(p) {
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if (p->mm && !is_init(p))
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/* Not swapper, init nor kernel thread */
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force_sig(sig, p);
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}
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}
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static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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send_sig_all(SIGTERM);
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console_loglevel = 8;
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}
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static struct sysrq_key_op sysrq_term_op = {
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.handler = sysrq_handle_term,
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.help_msg = "tErm",
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.action_msg = "Terminate All Tasks",
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.enable_mask = SYSRQ_ENABLE_SIGNAL,
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};
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static void moom_callback(void *ignored)
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{
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out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
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GFP_KERNEL, 0);
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}
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static DECLARE_WORK(moom_work, moom_callback, NULL);
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static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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schedule_work(&moom_work);
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}
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static struct sysrq_key_op sysrq_moom_op = {
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.handler = sysrq_handle_moom,
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.help_msg = "Full",
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.action_msg = "Manual OOM execution",
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};
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static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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send_sig_all(SIGKILL);
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console_loglevel = 8;
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}
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static struct sysrq_key_op sysrq_kill_op = {
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.handler = sysrq_handle_kill,
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.help_msg = "kIll",
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.action_msg = "Kill All Tasks",
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.enable_mask = SYSRQ_ENABLE_SIGNAL,
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};
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static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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normalize_rt_tasks();
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}
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static struct sysrq_key_op sysrq_unrt_op = {
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.handler = sysrq_handle_unrt,
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.help_msg = "Nice",
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.action_msg = "Nice All RT Tasks",
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.enable_mask = SYSRQ_ENABLE_RTNICE,
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};
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/* Key Operations table and lock */
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static DEFINE_SPINLOCK(sysrq_key_table_lock);
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static struct sysrq_key_op *sysrq_key_table[36] = {
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&sysrq_loglevel_op, /* 0 */
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&sysrq_loglevel_op, /* 1 */
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&sysrq_loglevel_op, /* 2 */
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&sysrq_loglevel_op, /* 3 */
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&sysrq_loglevel_op, /* 4 */
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&sysrq_loglevel_op, /* 5 */
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&sysrq_loglevel_op, /* 6 */
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&sysrq_loglevel_op, /* 7 */
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&sysrq_loglevel_op, /* 8 */
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&sysrq_loglevel_op, /* 9 */
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/*
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* Don't use for system provided sysrqs, it is handled specially on
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* sparc and will never arrive
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*/
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NULL, /* a */
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&sysrq_reboot_op, /* b */
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&sysrq_crashdump_op, /* c */
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&sysrq_showlocks_op, /* d */
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&sysrq_term_op, /* e */
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&sysrq_moom_op, /* f */
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NULL, /* g */
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NULL, /* h */
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&sysrq_kill_op, /* i */
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NULL, /* j */
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&sysrq_SAK_op, /* k */
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NULL, /* l */
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&sysrq_showmem_op, /* m */
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&sysrq_unrt_op, /* n */
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/* This will often be registered as 'Off' at init time */
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NULL, /* o */
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&sysrq_showregs_op, /* p */
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NULL, /* q */
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&sysrq_unraw_op, /* r */
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&sysrq_sync_op, /* s */
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&sysrq_showstate_op, /* t */
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&sysrq_mountro_op, /* u */
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/* May be assigned at init time by SMP VOYAGER */
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NULL, /* v */
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NULL, /* w */
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NULL, /* x */
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NULL, /* y */
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NULL /* z */
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};
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/* key2index calculation, -1 on invalid index */
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static int sysrq_key_table_key2index(int key)
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{
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int retval;
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if ((key >= '0') && (key <= '9'))
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retval = key - '0';
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else if ((key >= 'a') && (key <= 'z'))
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retval = key + 10 - 'a';
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else
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retval = -1;
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return retval;
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}
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/*
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* get and put functions for the table, exposed to modules.
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*/
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struct sysrq_key_op *__sysrq_get_key_op(int key)
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{
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struct sysrq_key_op *op_p = NULL;
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int i;
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i = sysrq_key_table_key2index(key);
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if (i != -1)
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op_p = sysrq_key_table[i];
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return op_p;
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}
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static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
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{
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int i = sysrq_key_table_key2index(key);
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if (i != -1)
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sysrq_key_table[i] = op_p;
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}
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/*
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* This is the non-locking version of handle_sysrq. It must/can only be called
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* by sysrq key handlers, as they are inside of the lock
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*/
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void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty,
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int check_mask)
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{
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struct sysrq_key_op *op_p;
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int orig_log_level;
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int i;
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unsigned long flags;
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spin_lock_irqsave(&sysrq_key_table_lock, flags);
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orig_log_level = console_loglevel;
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console_loglevel = 7;
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printk(KERN_INFO "SysRq : ");
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op_p = __sysrq_get_key_op(key);
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if (op_p) {
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/*
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* Should we check for enabled operations (/proc/sysrq-trigger
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* should not) and is the invoked operation enabled?
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*/
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if (!check_mask || sysrq_enabled == 1 ||
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(sysrq_enabled & op_p->enable_mask)) {
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printk("%s\n", op_p->action_msg);
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console_loglevel = orig_log_level;
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op_p->handler(key, pt_regs, tty);
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} else {
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printk("This sysrq operation is disabled.\n");
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}
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} else {
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printk("HELP : ");
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/* Only print the help msg once per handler */
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for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
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if (sysrq_key_table[i]) {
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int j;
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for (j = 0; sysrq_key_table[i] !=
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sysrq_key_table[j]; j++)
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;
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if (j != i)
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continue;
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printk("%s ", sysrq_key_table[i]->help_msg);
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}
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}
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printk("\n");
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console_loglevel = orig_log_level;
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}
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spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
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}
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/*
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* This function is called by the keyboard handler when SysRq is pressed
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* and any other keycode arrives.
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*/
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void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
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{
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if (!sysrq_enabled)
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return;
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__handle_sysrq(key, pt_regs, tty, 1);
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}
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EXPORT_SYMBOL(handle_sysrq);
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static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
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struct sysrq_key_op *remove_op_p)
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{
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int retval;
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unsigned long flags;
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spin_lock_irqsave(&sysrq_key_table_lock, flags);
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if (__sysrq_get_key_op(key) == remove_op_p) {
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__sysrq_put_key_op(key, insert_op_p);
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retval = 0;
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} else {
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retval = -1;
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}
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spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
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return retval;
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}
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int register_sysrq_key(int key, struct sysrq_key_op *op_p)
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{
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return __sysrq_swap_key_ops(key, op_p, NULL);
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}
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EXPORT_SYMBOL(register_sysrq_key);
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int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
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{
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return __sysrq_swap_key_ops(key, NULL, op_p);
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}
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EXPORT_SYMBOL(unregister_sysrq_key);
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