diff options
Diffstat (limited to 'drivers/char/sysrq.c')
| -rw-r--r-- | drivers/char/sysrq.c | 243 |
1 files changed, 213 insertions, 30 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index d4e8b213a46..5d15630a583 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -1,7 +1,4 @@ -/* -*- 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> @@ -10,8 +7,13 @@ * (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> @@ -39,33 +41,34 @@ #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 */ -int __read_mostly __sysrq_enabled = 1; - -static int __read_mostly sysrq_always_enabled; +static int __read_mostly sysrq_enabled = 1; +static bool __read_mostly sysrq_always_enabled; -int sysrq_on(void) +static bool sysrq_on(void) { - return __sysrq_enabled || sysrq_always_enabled; + 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) +static bool sysrq_on_mask(int mask) { - return sysrq_always_enabled || __sysrq_enabled == 1 || - (__sysrq_enabled & 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"); + sysrq_always_enabled = true; + pr_info("sysrq always enabled.\n"); return 1; } @@ -76,6 +79,7 @@ __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); @@ -101,7 +105,7 @@ static struct sysrq_key_op sysrq_SAK_op = { .enable_mask = SYSRQ_ENABLE_KEYBOARD, }; #else -#define sysrq_SAK_op (*(struct sysrq_key_op *)0) +#define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) #endif #ifdef CONFIG_VT @@ -119,7 +123,7 @@ static struct sysrq_key_op sysrq_unraw_op = { .enable_mask = SYSRQ_ENABLE_KEYBOARD, }; #else -#define sysrq_unraw_op (*(struct sysrq_key_op *)0) +#define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) #endif /* CONFIG_VT */ static void sysrq_handle_crash(int key, struct tty_struct *tty) @@ -195,7 +199,7 @@ static struct sysrq_key_op sysrq_showlocks_op = { .action_msg = "Show Locks Held", }; #else -#define sysrq_showlocks_op (*(struct sysrq_key_op *)0) +#define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) #endif #ifdef CONFIG_SMP @@ -298,7 +302,7 @@ static struct sysrq_key_op sysrq_ftrace_dump_op = { .enable_mask = SYSRQ_ENABLE_DUMP, }; #else -#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)0) +#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) #endif static void sysrq_handle_showmem(int key, struct tty_struct *tty) @@ -477,6 +481,7 @@ struct sysrq_key_op *__sysrq_get_key_op(int key) i = sysrq_key_table_key2index(key); if (i != -1) op_p = sysrq_key_table[i]; + return op_p; } @@ -488,11 +493,7 @@ static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) 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) +static void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) { struct sysrq_key_op *op_p; int orig_log_level; @@ -544,10 +545,6 @@ void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) 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()) @@ -555,10 +552,177 @@ void handle_sysrq(int key, struct tty_struct *tty) } 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 bool sysrq_filter(struct input_handle *handle, unsigned int type, + unsigned int code, int value) +{ + 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; + 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], NULL, 1); + break; + } + +out: + return sysrq_down; +} + +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 insteard of KEY_SYSRQ because not all + * keyboards have SysRq ikey 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; @@ -599,6 +763,7 @@ static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, return -EFAULT; __handle_sysrq(c, NULL, 0); } + return count; } @@ -606,10 +771,28 @@ static const struct file_operations proc_sysrq_trigger_operations = { .write = write_sysrq_trigger, }; +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) { - proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations); + sysrq_init_procfs(); + + if (sysrq_on()) + sysrq_register_handler(); + return 0; } module_init(sysrq_init); -#endif |