| /* |
| * 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/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 <linux/uaccess.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 = SYSRQ_DEFAULT_ENABLE; |
| 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(0); |
| } |
| 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; |
| |
| read_lock(&tasklist_lock); |
| for_each_process(p) { |
| if (p->mm && !is_global_init(p)) |
| /* Not swapper, init nor kernel thread */ |
| force_sig(sig, p); |
| } |
| read_unlock(&tasklist_lock); |
| } |
| |
| 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_CNT] = |
| "\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 */ |
| |
| struct sysrq_state { |
| struct input_handle handle; |
| struct work_struct reinject_work; |
| unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; |
| unsigned int alt; |
| unsigned int alt_use; |
| bool active; |
| bool need_reinject; |
| bool reinjecting; |
| }; |
| |
| static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
| { |
| struct sysrq_state *sysrq = |
| container_of(work, struct sysrq_state, reinject_work); |
| struct input_handle *handle = &sysrq->handle; |
| unsigned int alt_code = sysrq->alt_use; |
| |
| if (sysrq->need_reinject) { |
| /* we do not want the assignment to be reordered */ |
| sysrq->reinjecting = true; |
| mb(); |
| |
| /* Simulate press and release of Alt + SysRq */ |
| input_inject_event(handle, EV_KEY, alt_code, 1); |
| input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); |
| input_inject_event(handle, EV_SYN, SYN_REPORT, 1); |
| |
| input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); |
| input_inject_event(handle, EV_KEY, alt_code, 0); |
| input_inject_event(handle, EV_SYN, SYN_REPORT, 1); |
| |
| mb(); |
| sysrq->reinjecting = false; |
| } |
| } |
| |
| static bool sysrq_filter(struct input_handle *handle, |
| unsigned int type, unsigned int code, int value) |
| { |
| struct sysrq_state *sysrq = handle->private; |
| bool was_active = sysrq->active; |
| bool suppress; |
| |
| /* |
| * Do not filter anything if we are in the process of re-injecting |
| * Alt+SysRq combination. |
| */ |
| if (sysrq->reinjecting) |
| return false; |
| |
| switch (type) { |
| |
| case EV_SYN: |
| suppress = false; |
| break; |
| |
| case EV_KEY: |
| switch (code) { |
| |
| case KEY_LEFTALT: |
| case KEY_RIGHTALT: |
| if (!value) { |
| /* One of ALTs is being released */ |
| if (sysrq->active && code == sysrq->alt_use) |
| sysrq->active = false; |
| |
| sysrq->alt = KEY_RESERVED; |
| |
| } else if (value != 2) { |
| sysrq->alt = code; |
| sysrq->need_reinject = false; |
| } |
| break; |
| |
| case KEY_SYSRQ: |
| if (value == 1 && sysrq->alt != KEY_RESERVED) { |
| sysrq->active = true; |
| sysrq->alt_use = sysrq->alt; |
| /* |
| * If nothing else will be pressed we'll need |
| * to re-inject Alt-SysRq keysroke. |
| */ |
| sysrq->need_reinject = true; |
| } |
| |
| /* |
| * Pretend that sysrq was never pressed at all. This |
| * is needed to properly handle KGDB which will try |
| * to release all keys after exiting debugger. If we |
| * do not clear key bit it KGDB will end up sending |
| * release events for Alt and SysRq, potentially |
| * triggering print screen function. |
| */ |
| if (sysrq->active) |
| clear_bit(KEY_SYSRQ, handle->dev->key); |
| |
| break; |
| |
| default: |
| if (sysrq->active && value && value != 2) { |
| sysrq->need_reinject = false; |
| __handle_sysrq(sysrq_xlate[code], true); |
| } |
| break; |
| } |
| |
| suppress = sysrq->active; |
| |
| if (!sysrq->active) { |
| /* |
| * If we are not suppressing key presses keep track of |
| * keyboard state so we can release keys that have been |
| * pressed before entering SysRq mode. |
| */ |
| if (value) |
| set_bit(code, sysrq->key_down); |
| else |
| clear_bit(code, sysrq->key_down); |
| |
| if (was_active) |
| schedule_work(&sysrq->reinject_work); |
| |
| } else if (value == 0 && |
| test_and_clear_bit(code, sysrq->key_down)) { |
| /* |
| * Pass on release events for keys that was pressed before |
| * entering SysRq mode. |
| */ |
| suppress = false; |
| } |
| break; |
| |
| default: |
| suppress = sysrq->active; |
| break; |
| } |
| |
| return suppress; |
| } |
| |
| static int sysrq_connect(struct input_handler *handler, |
| struct input_dev *dev, |
| const struct input_device_id *id) |
| { |
| struct sysrq_state *sysrq; |
| int error; |
| |
| sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
| if (!sysrq) |
| return -ENOMEM; |
| |
| INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
| |
| sysrq->handle.dev = dev; |
| sysrq->handle.handler = handler; |
| sysrq->handle.name = "sysrq"; |
| sysrq->handle.private = sysrq; |
| |
| error = input_register_handle(&sysrq->handle); |
| if (error) { |
| pr_err("Failed to register input sysrq handler, error %d\n", |
| error); |
| goto err_free; |
| } |
| |
| error = input_open_device(&sysrq->handle); |
| if (error) { |
| pr_err("Failed to open input device, error %d\n", error); |
| goto err_unregister; |
| } |
| |
| return 0; |
| |
| err_unregister: |
| input_unregister_handle(&sysrq->handle); |
| err_free: |
| kfree(sysrq); |
| return error; |
| } |
| |
| static void sysrq_disconnect(struct input_handle *handle) |
| { |
| struct sysrq_state *sysrq = handle->private; |
| |
| input_close_device(handle); |
| cancel_work_sync(&sysrq->reinject_work); |
| input_unregister_handle(handle); |
| kfree(sysrq); |
| } |
| |
| /* |
| * 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); |