diff options
Diffstat (limited to 'drivers/char/sysrq.c')
| -rw-r--r-- | drivers/char/sysrq.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c new file mode 100644 index 0000000..ce0d9da --- /dev/null +++ b/drivers/char/sysrq.c @@ -0,0 +1,566 @@ +/* -*- 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/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/proc_fs.h> +#include <linux/quotaops.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 <linux/irq.h> +#include <linux/hrtimer.h> +#include <linux/oom.h> + +#include <asm/ptrace.h> +#include <asm/irq_regs.h> + +/* Whether we react on sysrq keys or just ignore them */ +int __read_mostly __sysrq_enabled = 1; + +static int __read_mostly sysrq_always_enabled; + +int sysrq_on(void) +{ + return __sysrq_enabled || sysrq_always_enabled; +} + +/* + * A value of 1 means 'all', other nonzero values are an op mask: + */ +static inline int sysrq_on_mask(int mask) +{ + return sysrq_always_enabled || __sysrq_enabled == 1 || + (__sysrq_enabled & mask); +} + +static int __init sysrq_always_enabled_setup(char *str) +{ + sysrq_always_enabled = 1; + printk(KERN_INFO "debug: sysrq always enabled.\n"); + + return 1; +} + +__setup("sysrq_always_enabled", sysrq_always_enabled_setup); + + +static void sysrq_handle_loglevel(int key, 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, +}; + +#ifdef CONFIG_VT +static void sysrq_handle_SAK(int key, struct tty_struct *tty) +{ + struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; + schedule_work(SAK_work); +} +static struct sysrq_key_op sysrq_SAK_op = { + .handler = sysrq_handle_SAK, + .help_msg = "saK", + .action_msg = "SAK", + .enable_mask = SYSRQ_ENABLE_KEYBOARD, +}; +#else +#define sysrq_SAK_op (*(struct sysrq_key_op *)0) +#endif + +#ifdef CONFIG_VT +static void sysrq_handle_unraw(int key, struct tty_struct *tty) +{ + struct kbd_struct *kbd = &kbd_table[fg_console]; + + if (kbd) + kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE; +} +static struct sysrq_key_op sysrq_unraw_op = { + .handler = sysrq_handle_unraw, + .help_msg = "unRaw", + .action_msg = "Keyboard mode set to system default", + .enable_mask = SYSRQ_ENABLE_KEYBOARD, +}; +#else +#define sysrq_unraw_op (*(struct sysrq_key_op *)0) +#endif /* CONFIG_VT */ + +#ifdef CONFIG_KEXEC +static void sysrq_handle_crashdump(int key, struct tty_struct *tty) +{ + crash_kexec(get_irq_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, +}; +#else +#define sysrq_crashdump_op (*(struct sysrq_key_op *)0) +#endif + +static void sysrq_handle_reboot(int key, struct tty_struct *tty) +{ + lockdep_off(); + 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 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_show_timers(int key, struct tty_struct *tty) +{ + sysrq_timer_list_show(); +} + +static struct sysrq_key_op sysrq_show_timers_op = { + .handler = sysrq_handle_show_timers, + .help_msg = "show-all-timers(Q)", + .action_msg = "Show clockevent devices & pending hrtimers (no others)", +}; + +static void sysrq_handle_mountro(int key, 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, +}; + +#ifdef CONFIG_LOCKDEP +static void sysrq_handle_showlocks(int key, struct tty_struct *tty) +{ + debug_show_all_locks(); +} + +static struct sysrq_key_op sysrq_showlocks_op = { + .handler = sysrq_handle_showlocks, + .help_msg = "show-all-locks(D)", + .action_msg = "Show Locks Held", +}; +#else +#define sysrq_showlocks_op (*(struct sysrq_key_op *)0) +#endif + +#ifdef CONFIG_SMP +static DEFINE_SPINLOCK(show_lock); + +static void showacpu(void *dummy) +{ + unsigned long flags; + + /* Idle CPUs have no interesting backtrace. */ + if (idle_cpu(smp_processor_id())) + return; + + spin_lock_irqsave(&show_lock, flags); + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_stack(NULL, NULL); + spin_unlock_irqrestore(&show_lock, flags); +} + +static void sysrq_showregs_othercpus(struct work_struct *dummy) +{ + smp_call_function(showacpu, NULL, 0); +} + +static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); + +static void sysrq_handle_showallcpus(int key, struct tty_struct *tty) +{ + struct pt_regs *regs = get_irq_regs(); + if (regs) { + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_regs(regs); + } + schedule_work(&sysrq_showallcpus); +} + +static struct sysrq_key_op sysrq_showallcpus_op = { + .handler = sysrq_handle_showallcpus, + .help_msg = "aLlcpus", + .action_msg = "Show backtrace of all active CPUs", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; +#endif + +static void sysrq_handle_showregs(int key, struct tty_struct *tty) +{ + struct pt_regs *regs = get_irq_regs(); + if (regs) + show_regs(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 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_showstate_blocked(int key, struct tty_struct *tty) +{ + show_state_filter(TASK_UNINTERRUPTIBLE); +} +static struct sysrq_key_op sysrq_showstate_blocked_op = { + .handler = sysrq_handle_showstate_blocked, + .help_msg = "shoW-blocked-tasks", + .action_msg = "Show Blocked State", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + + +static void sysrq_handle_showmem(int key, 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, +}; + +/* + * 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 && !is_global_init(p)) + /* Not swapper, init nor kernel thread */ + force_sig(sig, p); + } +} + +static void sysrq_handle_term(int key, 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(struct work_struct *ignored) +{ + out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0); +} + +static DECLARE_WORK(moom_work, moom_callback); + +static void sysrq_handle_moom(int key, 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", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; + +static void sysrq_handle_kill(int key, 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, +}; + +static void sysrq_handle_unrt(int key, 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); + +static struct sysrq_key_op *sysrq_key_table[36] = { + &sysrq_loglevel_op, /* 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 */ + + /* + * a: Don't use for system provided sysrqs, it is handled specially on + * sparc and will never arrive. + */ + NULL, /* a */ + &sysrq_reboot_op, /* b */ + &sysrq_crashdump_op, /* c & ibm_emac driver debug */ + &sysrq_showlocks_op, /* d */ + &sysrq_term_op, /* e */ + &sysrq_moom_op, /* f */ + /* g: May be registered by ppc for kgdb */ + NULL, /* g */ + NULL, /* h */ + &sysrq_kill_op, /* i */ + NULL, /* j */ + &sysrq_SAK_op, /* k */ +#ifdef CONFIG_SMP + &sysrq_showallcpus_op, /* l */ +#else + NULL, /* l */ +#endif + &sysrq_showmem_op, /* m */ + &sysrq_unrt_op, /* n */ + /* o: This will often be registered as 'Off' at init time */ + NULL, /* o */ + &sysrq_showregs_op, /* p */ + &sysrq_show_timers_op, /* q */ + &sysrq_unraw_op, /* r */ + &sysrq_sync_op, /* s */ + &sysrq_showstate_op, /* t */ + &sysrq_mountro_op, /* u */ + /* v: May be registered at init time by SMP VOYAGER */ + NULL, /* v */ + &sysrq_showstate_blocked_op, /* w */ + /* x: May be registered on ppc/powerpc for xmon */ + NULL, /* x */ + /* y: May be registered on sparc64 for global register dump */ + NULL, /* y */ + NULL /* z */ +}; + +/* 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 = NULL; + int i; + + i = sysrq_key_table_key2index(key); + if (i != -1) + op_p = sysrq_key_table[i]; + return op_p; +} + +static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) +{ + int 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 tty_struct *tty, int check_mask) +{ + struct sysrq_key_op *op_p; + int orig_log_level; + int i; + 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_on_mask(op_p->enable_mask)) { + printk("%s\n", op_p->action_msg); + console_loglevel = orig_log_level; + op_p->handler(key, tty); + } else { + printk("This sysrq operation is disabled.\n"); + } + } else { + printk("HELP : "); + /* Only print the help msg once per handler */ + for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { + if (sysrq_key_table[i]) { + int j; + + for (j = 0; sysrq_key_table[i] != + sysrq_key_table[j]; j++) + ; + if (j != i) + continue; + 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 tty_struct *tty) +{ + if (sysrq_on()) + __handle_sysrq(key, tty, 1); +} +EXPORT_SYMBOL(handle_sysrq); + +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); +} +EXPORT_SYMBOL(register_sysrq_key); + +int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) +{ + return __sysrq_swap_key_ops(key, NULL, op_p); +} +EXPORT_SYMBOL(unregister_sysrq_key); + +#ifdef CONFIG_PROC_FS +/* + * writing 'C' to /proc/sysrq-trigger is like sysrq-C + */ +static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + if (count) { + char c; + + if (get_user(c, buf)) + return -EFAULT; + __handle_sysrq(c, NULL, 0); + } + return count; +} + +static const struct file_operations proc_sysrq_trigger_operations = { + .write = write_sysrq_trigger, +}; + +static int __init sysrq_init(void) +{ + proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations); + return 0; +} +module_init(sysrq_init); +#endif |
