diff options
Diffstat (limited to 'drivers/char/sysrq.c')
| -rw-r--r-- | drivers/char/sysrq.c | 811 |
1 files changed, 0 insertions, 811 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c deleted file mode 100644 index eaa5d3efa79d..000000000000 --- a/drivers/char/sysrq.c +++ /dev/null @@ -1,811 +0,0 @@ -/* - * 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 - * - * Copyright (c) 2010 Dmitry Torokhov - * Input handler conversion - */ - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include <linux/sched.h> -#include <linux/interrupt.h> -#include <linux/mm.h> -#include <linux/fs.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/nmi.h> -#include <linux/quotaops.h> -#include <linux/perf_event.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/hrtimer.h> -#include <linux/oom.h> -#include <linux/slab.h> -#include <linux/input.h> - -#include <asm/ptrace.h> -#include <asm/irq_regs.h> - -/* Whether we react on sysrq keys or just ignore them */ -static int __read_mostly sysrq_enabled = 1; -static bool __read_mostly sysrq_always_enabled; - -static bool sysrq_on(void) -{ - return sysrq_enabled || sysrq_always_enabled; -} - -/* - * A value of 1 means 'all', other nonzero values are an op mask: - */ -static bool 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 = true; - pr_info("sysrq always enabled.\n"); - - return 1; -} - -__setup("sysrq_always_enabled", sysrq_always_enabled_setup); - - -static void sysrq_handle_loglevel(int key) -{ - 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 = "loglevel(0-9)", - .action_msg = "Changing Loglevel", - .enable_mask = SYSRQ_ENABLE_LOG, -}; - -#ifdef CONFIG_VT -static void sysrq_handle_SAK(int key) -{ - 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 *)NULL) -#endif - -#ifdef CONFIG_VT -static void sysrq_handle_unraw(int key) -{ - 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 *)NULL) -#endif /* CONFIG_VT */ - -static void sysrq_handle_crash(int key) -{ - char *killer = NULL; - - panic_on_oops = 1; /* force panic */ - wmb(); - *killer = 1; -} -static struct sysrq_key_op sysrq_crash_op = { - .handler = sysrq_handle_crash, - .help_msg = "Crash", - .action_msg = "Trigger a crash", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; - -static void sysrq_handle_reboot(int key) -{ - 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) -{ - 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) -{ - 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) -{ - 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) -{ - 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 *)NULL) -#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) -{ - /* - * Fall back to the workqueue based printing if the - * backtrace printing did not succeed or the - * architecture has no support for it: - */ - if (!trigger_all_cpu_backtrace()) { - 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 = "show-backtrace-all-active-cpus(L)", - .action_msg = "Show backtrace of all active CPUs", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; -#endif - -static void sysrq_handle_showregs(int key) -{ - struct pt_regs *regs = get_irq_regs(); - if (regs) - show_regs(regs); - perf_event_print_debug(); -} -static struct sysrq_key_op sysrq_showregs_op = { - .handler = sysrq_handle_showregs, - .help_msg = "show-registers(P)", - .action_msg = "Show Regs", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; - -static void sysrq_handle_showstate(int key) -{ - show_state(); -} -static struct sysrq_key_op sysrq_showstate_op = { - .handler = sysrq_handle_showstate, - .help_msg = "show-task-states(T)", - .action_msg = "Show State", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; - -static void sysrq_handle_showstate_blocked(int key) -{ - show_state_filter(TASK_UNINTERRUPTIBLE); -} -static struct sysrq_key_op sysrq_showstate_blocked_op = { - .handler = sysrq_handle_showstate_blocked, - .help_msg = "show-blocked-tasks(W)", - .action_msg = "Show Blocked State", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; - -#ifdef CONFIG_TRACING -#include <linux/ftrace.h> - -static void sysrq_ftrace_dump(int key) -{ - ftrace_dump(DUMP_ALL); -} -static struct sysrq_key_op sysrq_ftrace_dump_op = { - .handler = sysrq_ftrace_dump, - .help_msg = "dump-ftrace-buffer(Z)", - .action_msg = "Dump ftrace buffer", - .enable_mask = SYSRQ_ENABLE_DUMP, -}; -#else -#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) -#endif - -static void sysrq_handle_showmem(int key) -{ - show_mem(); -} -static struct sysrq_key_op sysrq_showmem_op = { - .handler = sysrq_handle_showmem, - .help_msg = "show-memory-usage(M)", - .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) -{ - send_sig_all(SIGTERM); - console_loglevel = 8; -} -static struct sysrq_key_op sysrq_term_op = { - .handler = sysrq_handle_term, - .help_msg = "terminate-all-tasks(E)", - .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, NULL); -} - -static DECLARE_WORK(moom_work, moom_callback); - -static void sysrq_handle_moom(int key) -{ - schedule_work(&moom_work); -} -static struct sysrq_key_op sysrq_moom_op = { - .handler = sysrq_handle_moom, - .help_msg = "memory-full-oom-kill(F)", - .action_msg = "Manual OOM execution", - .enable_mask = SYSRQ_ENABLE_SIGNAL, -}; - -#ifdef CONFIG_BLOCK -static void sysrq_handle_thaw(int key) -{ - emergency_thaw_all(); -} -static struct sysrq_key_op sysrq_thaw_op = { - .handler = sysrq_handle_thaw, - .help_msg = "thaw-filesystems(J)", - .action_msg = "Emergency Thaw of all frozen filesystems", - .enable_mask = SYSRQ_ENABLE_SIGNAL, -}; -#endif - -static void sysrq_handle_kill(int key) -{ - send_sig_all(SIGKILL); - console_loglevel = 8; -} -static struct sysrq_key_op sysrq_kill_op = { - .handler = sysrq_handle_kill, - .help_msg = "kill-all-tasks(I)", - .action_msg = "Kill All Tasks", - .enable_mask = SYSRQ_ENABLE_SIGNAL, -}; - -static void sysrq_handle_unrt(int key) -{ - normalize_rt_tasks(); -} -static struct sysrq_key_op sysrq_unrt_op = { - .handler = sysrq_handle_unrt, - .help_msg = "nice-all-RT-tasks(N)", - .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_crash_op, /* c & ibm_emac driver debug */ - &sysrq_showlocks_op, /* d */ - &sysrq_term_op, /* e */ - &sysrq_moom_op, /* f */ - /* g: May be registered for the kernel debugger */ - NULL, /* g */ - NULL, /* h - reserved for help */ - &sysrq_kill_op, /* i */ -#ifdef CONFIG_BLOCK - &sysrq_thaw_op, /* j */ -#else - NULL, /* j */ -#endif - &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 for frame buffer console restore */ - 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 */ - &sysrq_ftrace_dump_op, /* 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; -} - -void __handle_sysrq(int key, bool 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); - /* - * Raise the apparent loglevel to maximum so that the sysrq header - * is shown to provide the user with positive feedback. We do not - * simply emit this at KERN_EMERG as that would change message - * routing in the consumers of /proc/kmsg. - */ - 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); - } 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); -} - -void handle_sysrq(int key) -{ - if (sysrq_on()) - __handle_sysrq(key, true); -} -EXPORT_SYMBOL(handle_sysrq); - -#ifdef CONFIG_INPUT - -/* Simple translation table for the SysRq keys */ -static const unsigned char sysrq_xlate[KEY_MAX + 1] = - "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ - "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ - "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ - "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ - "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ - "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ - "\r\000/"; /* 0x60 - 0x6f */ - -static bool sysrq_down; -static int sysrq_alt_use; -static int sysrq_alt; -static DEFINE_SPINLOCK(sysrq_event_lock); - -static bool sysrq_filter(struct input_handle *handle, unsigned int type, - unsigned int code, int value) -{ - bool suppress; - - /* We are called with interrupts disabled, just take the lock */ - spin_lock(&sysrq_event_lock); - - if (type != EV_KEY) - goto out; - - switch (code) { - - case KEY_LEFTALT: - case KEY_RIGHTALT: - if (value) - sysrq_alt = code; - else { - if (sysrq_down && code == sysrq_alt_use) - sysrq_down = false; - - sysrq_alt = 0; - } - break; - - case KEY_SYSRQ: - if (value == 1 && sysrq_alt) { - sysrq_down = true; - sysrq_alt_use = sysrq_alt; - } - break; - - default: - if (sysrq_down && value && value != 2) - __handle_sysrq(sysrq_xlate[code], true); - break; - } - -out: - suppress = sysrq_down; - spin_unlock(&sysrq_event_lock); - - return suppress; -} - -static int sysrq_connect(struct input_handler *handler, - struct input_dev *dev, - const struct input_device_id *id) -{ - struct input_handle *handle; - int error; - - sysrq_down = false; - sysrq_alt = 0; - - handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); - if (!handle) - return -ENOMEM; - - handle->dev = dev; - handle->handler = handler; - handle->name = "sysrq"; - - error = input_register_handle(handle); - if (error) { - pr_err("Failed to register input sysrq handler, error %d\n", - error); - goto err_free; - } - - error = input_open_device(handle); - if (error) { - pr_err("Failed to open input device, error %d\n", error); - goto err_unregister; - } - - return 0; - - err_unregister: - input_unregister_handle(handle); - err_free: - kfree(handle); - return error; -} - -static void sysrq_disconnect(struct input_handle *handle) -{ - input_close_device(handle); - input_unregister_handle(handle); - kfree(handle); -} - -/* - * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all - * keyboards have SysRq key predefined and so user may add it to keymap - * later, but we expect all such keyboards to have left alt. - */ -static const struct input_device_id sysrq_ids[] = { - { - .flags = INPUT_DEVICE_ID_MATCH_EVBIT | - INPUT_DEVICE_ID_MATCH_KEYBIT, - .evbit = { BIT_MASK(EV_KEY) }, - .keybit = { BIT_MASK(KEY_LEFTALT) }, - }, - { }, -}; - -static struct input_handler sysrq_handler = { - .filter = sysrq_filter, - .connect = sysrq_connect, - .disconnect = sysrq_disconnect, - .name = "sysrq", - .id_table = sysrq_ids, -}; - -static bool sysrq_handler_registered; - -static inline void sysrq_register_handler(void) -{ - int error; - - error = input_register_handler(&sysrq_handler); - if (error) - pr_err("Failed to register input handler, error %d", error); - else - sysrq_handler_registered = true; -} - -static inline void sysrq_unregister_handler(void) -{ - if (sysrq_handler_registered) { - input_unregister_handler(&sysrq_handler); - sysrq_handler_registered = false; - } -} - -#else - -static inline void sysrq_register_handler(void) -{ -} - -static inline void sysrq_unregister_handler(void) -{ -} - -#endif /* CONFIG_INPUT */ - -int sysrq_toggle_support(int enable_mask) -{ - bool was_enabled = sysrq_on(); - - sysrq_enabled = enable_mask; - - if (was_enabled != sysrq_on()) { - if (sysrq_on()) - sysrq_register_handler(); - else - sysrq_unregister_handler(); - } - - return 0; -} - -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, false); - } - - return count; -} - -static const struct file_operations proc_sysrq_trigger_operations = { - .write = write_sysrq_trigger, - .llseek = noop_llseek, -}; - -static void sysrq_init_procfs(void) -{ - if (!proc_create("sysrq-trigger", S_IWUSR, NULL, - &proc_sysrq_trigger_operations)) - pr_err("Failed to register proc interface\n"); -} - -#else - -static inline void sysrq_init_procfs(void) -{ -} - -#endif /* CONFIG_PROC_FS */ - -static int __init sysrq_init(void) -{ - sysrq_init_procfs(); - - if (sysrq_on()) - sysrq_register_handler(); - - return 0; -} -module_init(sysrq_init); |