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OpenCloudOS-Kernel/drivers/char/sysrq.c

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/*
* 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/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/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, 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 = "loglevel(0-9)",
.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 *)NULL)
#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 *)NULL)
#endif /* CONFIG_VT */
static void sysrq_handle_crash(int key, struct tty_struct *tty)
{
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, 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 *)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, struct tty_struct *tty)
{
/*
* 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 tty_struct *tty)
{
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, struct tty_struct *tty)
{
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, 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(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, struct tty_struct *tty)
{
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, struct tty_struct *tty)
{
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, 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 = "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, struct tty_struct *tty)
{
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, struct tty_struct *tty)
{
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, 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-all-tasks(I)",
.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-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, 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);
/*
* 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, 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);
}
void handle_sysrq(int key, struct tty_struct *tty)
{
if (sysrq_on())
__handle_sysrq(key, tty, 1);
}
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;
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], 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;
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 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);
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