/* -*- 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);