| /* -*- 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; |
| } |
| |
| static 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); |
| } |
| |
| static 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); |