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1192 lines
28 KiB
1192 lines
28 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Linux Magic System Request Key Hacks |
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* |
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* (c) 1997 Martin Mares <[email protected]> |
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* based on ideas by Pavel Machek <[email protected]> |
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* |
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* (c) 2000 Crutcher Dunnavant <[email protected]> |
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* overhauled to use key registration |
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* based upon discusions in irc://irc.openprojects.net/#kernelnewbies |
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* |
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* Copyright (c) 2010 Dmitry Torokhov |
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* Input handler conversion |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/sched/signal.h> |
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#include <linux/sched/rt.h> |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task.h> |
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#include <linux/ctype.h> |
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#include <linux/interrupt.h> |
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#include <linux/mm.h> |
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#include <linux/fs.h> |
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#include <linux/mount.h> |
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#include <linux/kdev_t.h> |
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#include <linux/major.h> |
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#include <linux/reboot.h> |
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#include <linux/sysrq.h> |
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#include <linux/kbd_kern.h> |
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#include <linux/proc_fs.h> |
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#include <linux/nmi.h> |
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#include <linux/quotaops.h> |
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#include <linux/perf_event.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/suspend.h> |
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#include <linux/writeback.h> |
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#include <linux/swap.h> |
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#include <linux/spinlock.h> |
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#include <linux/vt_kern.h> |
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#include <linux/workqueue.h> |
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#include <linux/hrtimer.h> |
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#include <linux/oom.h> |
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#include <linux/slab.h> |
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#include <linux/input.h> |
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#include <linux/uaccess.h> |
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#include <linux/moduleparam.h> |
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#include <linux/jiffies.h> |
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#include <linux/syscalls.h> |
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#include <linux/of.h> |
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#include <linux/rcupdate.h> |
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#include <asm/ptrace.h> |
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#include <asm/irq_regs.h> |
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/* Whether we react on sysrq keys or just ignore them */ |
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static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; |
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static bool __read_mostly sysrq_always_enabled; |
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static bool sysrq_on(void) |
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{ |
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return sysrq_enabled || sysrq_always_enabled; |
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} |
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/** |
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* sysrq_mask - Getter for sysrq_enabled mask. |
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* |
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* Return: 1 if sysrq is always enabled, enabled sysrq_key_op mask otherwise. |
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*/ |
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int sysrq_mask(void) |
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{ |
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if (sysrq_always_enabled) |
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return 1; |
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return sysrq_enabled; |
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} |
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EXPORT_SYMBOL_GPL(sysrq_mask); |
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/* |
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* A value of 1 means 'all', other nonzero values are an op mask: |
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*/ |
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static bool sysrq_on_mask(int mask) |
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{ |
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return sysrq_always_enabled || |
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sysrq_enabled == 1 || |
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(sysrq_enabled & mask); |
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} |
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static int __init sysrq_always_enabled_setup(char *str) |
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{ |
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sysrq_always_enabled = true; |
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pr_info("sysrq always enabled.\n"); |
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return 1; |
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} |
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__setup("sysrq_always_enabled", sysrq_always_enabled_setup); |
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static void sysrq_handle_loglevel(int key) |
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{ |
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int i; |
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i = key - '0'; |
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console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
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pr_info("Loglevel set to %d\n", i); |
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console_loglevel = i; |
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} |
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static const struct sysrq_key_op sysrq_loglevel_op = { |
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.handler = sysrq_handle_loglevel, |
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.help_msg = "loglevel(0-9)", |
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.action_msg = "Changing Loglevel", |
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.enable_mask = SYSRQ_ENABLE_LOG, |
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}; |
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#ifdef CONFIG_VT |
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static void sysrq_handle_SAK(int key) |
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{ |
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struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
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schedule_work(SAK_work); |
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} |
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static const struct sysrq_key_op sysrq_SAK_op = { |
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.handler = sysrq_handle_SAK, |
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.help_msg = "sak(k)", |
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.action_msg = "SAK", |
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.enable_mask = SYSRQ_ENABLE_KEYBOARD, |
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}; |
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#else |
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#define sysrq_SAK_op (*(const struct sysrq_key_op *)NULL) |
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#endif |
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#ifdef CONFIG_VT |
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static void sysrq_handle_unraw(int key) |
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{ |
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vt_reset_unicode(fg_console); |
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} |
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static const struct sysrq_key_op sysrq_unraw_op = { |
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.handler = sysrq_handle_unraw, |
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.help_msg = "unraw(r)", |
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.action_msg = "Keyboard mode set to system default", |
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.enable_mask = SYSRQ_ENABLE_KEYBOARD, |
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}; |
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#else |
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#define sysrq_unraw_op (*(const struct sysrq_key_op *)NULL) |
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#endif /* CONFIG_VT */ |
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static void sysrq_handle_crash(int key) |
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{ |
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/* release the RCU read lock before crashing */ |
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rcu_read_unlock(); |
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panic("sysrq triggered crash\n"); |
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} |
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static const struct sysrq_key_op sysrq_crash_op = { |
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.handler = sysrq_handle_crash, |
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.help_msg = "crash(c)", |
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.action_msg = "Trigger a crash", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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static void sysrq_handle_reboot(int key) |
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{ |
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lockdep_off(); |
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local_irq_enable(); |
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emergency_restart(); |
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} |
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static const struct sysrq_key_op sysrq_reboot_op = { |
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.handler = sysrq_handle_reboot, |
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.help_msg = "reboot(b)", |
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.action_msg = "Resetting", |
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.enable_mask = SYSRQ_ENABLE_BOOT, |
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}; |
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const struct sysrq_key_op *__sysrq_reboot_op = &sysrq_reboot_op; |
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static void sysrq_handle_sync(int key) |
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{ |
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emergency_sync(); |
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} |
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static const struct sysrq_key_op sysrq_sync_op = { |
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.handler = sysrq_handle_sync, |
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.help_msg = "sync(s)", |
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.action_msg = "Emergency Sync", |
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.enable_mask = SYSRQ_ENABLE_SYNC, |
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}; |
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static void sysrq_handle_show_timers(int key) |
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{ |
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sysrq_timer_list_show(); |
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} |
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static const struct sysrq_key_op sysrq_show_timers_op = { |
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.handler = sysrq_handle_show_timers, |
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.help_msg = "show-all-timers(q)", |
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.action_msg = "Show clockevent devices & pending hrtimers (no others)", |
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}; |
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static void sysrq_handle_mountro(int key) |
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{ |
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emergency_remount(); |
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} |
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static const struct sysrq_key_op sysrq_mountro_op = { |
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.handler = sysrq_handle_mountro, |
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.help_msg = "unmount(u)", |
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.action_msg = "Emergency Remount R/O", |
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.enable_mask = SYSRQ_ENABLE_REMOUNT, |
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}; |
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#ifdef CONFIG_LOCKDEP |
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static void sysrq_handle_showlocks(int key) |
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{ |
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debug_show_all_locks(); |
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} |
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static const struct sysrq_key_op sysrq_showlocks_op = { |
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.handler = sysrq_handle_showlocks, |
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.help_msg = "show-all-locks(d)", |
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.action_msg = "Show Locks Held", |
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}; |
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#else |
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#define sysrq_showlocks_op (*(const struct sysrq_key_op *)NULL) |
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#endif |
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#ifdef CONFIG_SMP |
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static DEFINE_RAW_SPINLOCK(show_lock); |
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static void showacpu(void *dummy) |
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{ |
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unsigned long flags; |
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/* Idle CPUs have no interesting backtrace. */ |
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if (idle_cpu(smp_processor_id())) |
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return; |
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raw_spin_lock_irqsave(&show_lock, flags); |
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pr_info("CPU%d:\n", smp_processor_id()); |
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show_stack(NULL, NULL, KERN_INFO); |
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raw_spin_unlock_irqrestore(&show_lock, flags); |
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} |
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static void sysrq_showregs_othercpus(struct work_struct *dummy) |
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{ |
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smp_call_function(showacpu, NULL, 0); |
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} |
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static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); |
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static void sysrq_handle_showallcpus(int key) |
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{ |
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/* |
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* Fall back to the workqueue based printing if the |
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* backtrace printing did not succeed or the |
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* architecture has no support for it: |
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*/ |
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if (!trigger_all_cpu_backtrace()) { |
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struct pt_regs *regs = NULL; |
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if (in_irq()) |
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regs = get_irq_regs(); |
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if (regs) { |
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pr_info("CPU%d:\n", smp_processor_id()); |
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show_regs(regs); |
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} |
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schedule_work(&sysrq_showallcpus); |
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} |
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} |
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static const struct sysrq_key_op sysrq_showallcpus_op = { |
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.handler = sysrq_handle_showallcpus, |
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.help_msg = "show-backtrace-all-active-cpus(l)", |
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.action_msg = "Show backtrace of all active CPUs", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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#endif |
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static void sysrq_handle_showregs(int key) |
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{ |
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struct pt_regs *regs = NULL; |
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if (in_irq()) |
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regs = get_irq_regs(); |
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if (regs) |
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show_regs(regs); |
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perf_event_print_debug(); |
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} |
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static const struct sysrq_key_op sysrq_showregs_op = { |
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.handler = sysrq_handle_showregs, |
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.help_msg = "show-registers(p)", |
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.action_msg = "Show Regs", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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static void sysrq_handle_showstate(int key) |
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{ |
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show_state(); |
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show_workqueue_state(); |
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} |
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static const struct sysrq_key_op sysrq_showstate_op = { |
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.handler = sysrq_handle_showstate, |
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.help_msg = "show-task-states(t)", |
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.action_msg = "Show State", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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static void sysrq_handle_showstate_blocked(int key) |
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{ |
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show_state_filter(TASK_UNINTERRUPTIBLE); |
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} |
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static const struct sysrq_key_op sysrq_showstate_blocked_op = { |
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.handler = sysrq_handle_showstate_blocked, |
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.help_msg = "show-blocked-tasks(w)", |
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.action_msg = "Show Blocked State", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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#ifdef CONFIG_TRACING |
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#include <linux/ftrace.h> |
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static void sysrq_ftrace_dump(int key) |
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{ |
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ftrace_dump(DUMP_ALL); |
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} |
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static const struct sysrq_key_op sysrq_ftrace_dump_op = { |
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.handler = sysrq_ftrace_dump, |
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.help_msg = "dump-ftrace-buffer(z)", |
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.action_msg = "Dump ftrace buffer", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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#else |
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#define sysrq_ftrace_dump_op (*(const struct sysrq_key_op *)NULL) |
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#endif |
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static void sysrq_handle_showmem(int key) |
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{ |
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show_mem(0, NULL); |
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} |
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static const struct sysrq_key_op sysrq_showmem_op = { |
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.handler = sysrq_handle_showmem, |
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.help_msg = "show-memory-usage(m)", |
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.action_msg = "Show Memory", |
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.enable_mask = SYSRQ_ENABLE_DUMP, |
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}; |
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/* |
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* Signal sysrq helper function. Sends a signal to all user processes. |
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*/ |
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static void send_sig_all(int sig) |
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{ |
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struct task_struct *p; |
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read_lock(&tasklist_lock); |
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for_each_process(p) { |
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if (p->flags & PF_KTHREAD) |
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continue; |
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if (is_global_init(p)) |
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continue; |
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do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
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} |
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read_unlock(&tasklist_lock); |
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} |
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static void sysrq_handle_term(int key) |
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{ |
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send_sig_all(SIGTERM); |
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console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
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} |
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static const struct sysrq_key_op sysrq_term_op = { |
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.handler = sysrq_handle_term, |
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.help_msg = "terminate-all-tasks(e)", |
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.action_msg = "Terminate All Tasks", |
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.enable_mask = SYSRQ_ENABLE_SIGNAL, |
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}; |
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static void moom_callback(struct work_struct *ignored) |
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{ |
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const gfp_t gfp_mask = GFP_KERNEL; |
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struct oom_control oc = { |
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.zonelist = node_zonelist(first_memory_node, gfp_mask), |
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.nodemask = NULL, |
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.memcg = NULL, |
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.gfp_mask = gfp_mask, |
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.order = -1, |
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}; |
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mutex_lock(&oom_lock); |
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if (!out_of_memory(&oc)) |
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pr_info("OOM request ignored. No task eligible\n"); |
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mutex_unlock(&oom_lock); |
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} |
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static DECLARE_WORK(moom_work, moom_callback); |
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static void sysrq_handle_moom(int key) |
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{ |
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schedule_work(&moom_work); |
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} |
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static const struct sysrq_key_op sysrq_moom_op = { |
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.handler = sysrq_handle_moom, |
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.help_msg = "memory-full-oom-kill(f)", |
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.action_msg = "Manual OOM execution", |
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.enable_mask = SYSRQ_ENABLE_SIGNAL, |
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}; |
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static void sysrq_handle_thaw(int key) |
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{ |
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emergency_thaw_all(); |
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} |
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static const struct sysrq_key_op sysrq_thaw_op = { |
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.handler = sysrq_handle_thaw, |
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.help_msg = "thaw-filesystems(j)", |
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.action_msg = "Emergency Thaw of all frozen filesystems", |
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.enable_mask = SYSRQ_ENABLE_SIGNAL, |
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}; |
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static void sysrq_handle_kill(int key) |
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{ |
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send_sig_all(SIGKILL); |
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console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
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} |
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static const struct sysrq_key_op sysrq_kill_op = { |
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.handler = sysrq_handle_kill, |
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.help_msg = "kill-all-tasks(i)", |
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.action_msg = "Kill All Tasks", |
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.enable_mask = SYSRQ_ENABLE_SIGNAL, |
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}; |
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static void sysrq_handle_unrt(int key) |
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{ |
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normalize_rt_tasks(); |
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} |
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static const struct sysrq_key_op sysrq_unrt_op = { |
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.handler = sysrq_handle_unrt, |
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.help_msg = "nice-all-RT-tasks(n)", |
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.action_msg = "Nice All RT Tasks", |
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.enable_mask = SYSRQ_ENABLE_RTNICE, |
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}; |
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/* Key Operations table and lock */ |
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static DEFINE_SPINLOCK(sysrq_key_table_lock); |
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static const struct sysrq_key_op *sysrq_key_table[62] = { |
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&sysrq_loglevel_op, /* 0 */ |
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&sysrq_loglevel_op, /* 1 */ |
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&sysrq_loglevel_op, /* 2 */ |
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&sysrq_loglevel_op, /* 3 */ |
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&sysrq_loglevel_op, /* 4 */ |
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&sysrq_loglevel_op, /* 5 */ |
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&sysrq_loglevel_op, /* 6 */ |
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&sysrq_loglevel_op, /* 7 */ |
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&sysrq_loglevel_op, /* 8 */ |
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&sysrq_loglevel_op, /* 9 */ |
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|
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/* |
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* a: Don't use for system provided sysrqs, it is handled specially on |
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* sparc and will never arrive. |
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*/ |
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NULL, /* a */ |
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&sysrq_reboot_op, /* b */ |
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&sysrq_crash_op, /* c */ |
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&sysrq_showlocks_op, /* d */ |
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&sysrq_term_op, /* e */ |
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&sysrq_moom_op, /* f */ |
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/* g: May be registered for the kernel debugger */ |
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NULL, /* g */ |
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NULL, /* h - reserved for help */ |
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&sysrq_kill_op, /* i */ |
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#ifdef CONFIG_BLOCK |
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&sysrq_thaw_op, /* j */ |
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#else |
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NULL, /* j */ |
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#endif |
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&sysrq_SAK_op, /* k */ |
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#ifdef CONFIG_SMP |
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&sysrq_showallcpus_op, /* l */ |
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#else |
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NULL, /* l */ |
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#endif |
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&sysrq_showmem_op, /* m */ |
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&sysrq_unrt_op, /* n */ |
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/* o: This will often be registered as 'Off' at init time */ |
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NULL, /* o */ |
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&sysrq_showregs_op, /* p */ |
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&sysrq_show_timers_op, /* q */ |
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&sysrq_unraw_op, /* r */ |
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&sysrq_sync_op, /* s */ |
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&sysrq_showstate_op, /* t */ |
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&sysrq_mountro_op, /* u */ |
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/* v: May be registered for frame buffer console restore */ |
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NULL, /* v */ |
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&sysrq_showstate_blocked_op, /* w */ |
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/* x: May be registered on mips for TLB dump */ |
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/* x: May be registered on ppc/powerpc for xmon */ |
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/* x: May be registered on sparc64 for global PMU dump */ |
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NULL, /* x */ |
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/* y: May be registered on sparc64 for global register dump */ |
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NULL, /* y */ |
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&sysrq_ftrace_dump_op, /* z */ |
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NULL, /* A */ |
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NULL, /* B */ |
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NULL, /* C */ |
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NULL, /* D */ |
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NULL, /* E */ |
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NULL, /* F */ |
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NULL, /* G */ |
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NULL, /* H */ |
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NULL, /* I */ |
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NULL, /* J */ |
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NULL, /* K */ |
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NULL, /* L */ |
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NULL, /* M */ |
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NULL, /* N */ |
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NULL, /* O */ |
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NULL, /* P */ |
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NULL, /* Q */ |
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NULL, /* R */ |
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NULL, /* S */ |
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NULL, /* T */ |
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NULL, /* U */ |
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NULL, /* V */ |
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NULL, /* W */ |
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NULL, /* X */ |
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NULL, /* Y */ |
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NULL, /* Z */ |
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}; |
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|
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/* key2index calculation, -1 on invalid index */ |
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static int sysrq_key_table_key2index(int key) |
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{ |
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int retval; |
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|
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if ((key >= '0') && (key <= '9')) |
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retval = key - '0'; |
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else if ((key >= 'a') && (key <= 'z')) |
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retval = key + 10 - 'a'; |
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else if ((key >= 'A') && (key <= 'Z')) |
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retval = key + 36 - 'A'; |
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else |
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retval = -1; |
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return retval; |
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} |
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|
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/* |
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* get and put functions for the table, exposed to modules. |
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*/ |
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static const struct sysrq_key_op *__sysrq_get_key_op(int key) |
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{ |
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const struct sysrq_key_op *op_p = NULL; |
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int i; |
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|
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i = sysrq_key_table_key2index(key); |
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if (i != -1) |
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op_p = sysrq_key_table[i]; |
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|
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return op_p; |
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} |
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|
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static void __sysrq_put_key_op(int key, const struct sysrq_key_op *op_p) |
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{ |
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int i = sysrq_key_table_key2index(key); |
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|
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if (i != -1) |
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sysrq_key_table[i] = op_p; |
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} |
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|
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void __handle_sysrq(int key, bool check_mask) |
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{ |
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const struct sysrq_key_op *op_p; |
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int orig_log_level; |
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int orig_suppress_printk; |
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int i; |
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|
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orig_suppress_printk = suppress_printk; |
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suppress_printk = 0; |
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|
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rcu_sysrq_start(); |
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rcu_read_lock(); |
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/* |
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* Raise the apparent loglevel to maximum so that the sysrq header |
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* 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 = CONSOLE_LOGLEVEL_DEFAULT; |
|
|
|
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)) { |
|
pr_info("%s\n", op_p->action_msg); |
|
console_loglevel = orig_log_level; |
|
op_p->handler(key); |
|
} else { |
|
pr_info("This sysrq operation is disabled.\n"); |
|
console_loglevel = orig_log_level; |
|
} |
|
} else { |
|
pr_info("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; |
|
pr_cont("%s ", sysrq_key_table[i]->help_msg); |
|
} |
|
} |
|
pr_cont("\n"); |
|
console_loglevel = orig_log_level; |
|
} |
|
rcu_read_unlock(); |
|
rcu_sysrq_end(); |
|
|
|
suppress_printk = orig_suppress_printk; |
|
} |
|
|
|
void handle_sysrq(int key) |
|
{ |
|
if (sysrq_on()) |
|
__handle_sysrq(key, true); |
|
} |
|
EXPORT_SYMBOL(handle_sysrq); |
|
|
|
#ifdef CONFIG_INPUT |
|
static int sysrq_reset_downtime_ms; |
|
|
|
/* 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; |
|
unsigned int shift; |
|
unsigned int shift_use; |
|
bool active; |
|
bool need_reinject; |
|
bool reinjecting; |
|
|
|
/* reset sequence handling */ |
|
bool reset_canceled; |
|
bool reset_requested; |
|
unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
|
int reset_seq_len; |
|
int reset_seq_cnt; |
|
int reset_seq_version; |
|
struct timer_list keyreset_timer; |
|
}; |
|
|
|
#define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
|
static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; |
|
static unsigned int sysrq_reset_seq_len; |
|
static unsigned int sysrq_reset_seq_version = 1; |
|
|
|
static void sysrq_parse_reset_sequence(struct sysrq_state *state) |
|
{ |
|
int i; |
|
unsigned short key; |
|
|
|
state->reset_seq_cnt = 0; |
|
|
|
for (i = 0; i < sysrq_reset_seq_len; i++) { |
|
key = sysrq_reset_seq[i]; |
|
|
|
if (key == KEY_RESERVED || key > KEY_MAX) |
|
break; |
|
|
|
__set_bit(key, state->reset_keybit); |
|
state->reset_seq_len++; |
|
|
|
if (test_bit(key, state->key_down)) |
|
state->reset_seq_cnt++; |
|
} |
|
|
|
/* Disable reset until old keys are not released */ |
|
state->reset_canceled = state->reset_seq_cnt != 0; |
|
|
|
state->reset_seq_version = sysrq_reset_seq_version; |
|
} |
|
|
|
static void sysrq_do_reset(struct timer_list *t) |
|
{ |
|
struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
|
|
|
state->reset_requested = true; |
|
|
|
orderly_reboot(); |
|
} |
|
|
|
static void sysrq_handle_reset_request(struct sysrq_state *state) |
|
{ |
|
if (state->reset_requested) |
|
__handle_sysrq(sysrq_xlate[KEY_B], false); |
|
|
|
if (sysrq_reset_downtime_ms) |
|
mod_timer(&state->keyreset_timer, |
|
jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); |
|
else |
|
sysrq_do_reset(&state->keyreset_timer); |
|
} |
|
|
|
static void sysrq_detect_reset_sequence(struct sysrq_state *state, |
|
unsigned int code, int value) |
|
{ |
|
if (!test_bit(code, state->reset_keybit)) { |
|
/* |
|
* Pressing any key _not_ in reset sequence cancels |
|
* the reset sequence. Also cancelling the timer in |
|
* case additional keys were pressed after a reset |
|
* has been requested. |
|
*/ |
|
if (value && state->reset_seq_cnt) { |
|
state->reset_canceled = true; |
|
del_timer(&state->keyreset_timer); |
|
} |
|
} else if (value == 0) { |
|
/* |
|
* Key release - all keys in the reset sequence need |
|
* to be pressed and held for the reset timeout |
|
* to hold. |
|
*/ |
|
del_timer(&state->keyreset_timer); |
|
|
|
if (--state->reset_seq_cnt == 0) |
|
state->reset_canceled = false; |
|
} else if (value == 1) { |
|
/* key press, not autorepeat */ |
|
if (++state->reset_seq_cnt == state->reset_seq_len && |
|
!state->reset_canceled) { |
|
sysrq_handle_reset_request(state); |
|
} |
|
} |
|
} |
|
|
|
#ifdef CONFIG_OF |
|
static void sysrq_of_get_keyreset_config(void) |
|
{ |
|
u32 key; |
|
struct device_node *np; |
|
struct property *prop; |
|
const __be32 *p; |
|
|
|
np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); |
|
if (!np) { |
|
pr_debug("No sysrq node found"); |
|
return; |
|
} |
|
|
|
/* Reset in case a __weak definition was present */ |
|
sysrq_reset_seq_len = 0; |
|
|
|
of_property_for_each_u32(np, "keyset", prop, p, key) { |
|
if (key == KEY_RESERVED || key > KEY_MAX || |
|
sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) |
|
break; |
|
|
|
sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; |
|
} |
|
|
|
/* Get reset timeout if any. */ |
|
of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); |
|
|
|
of_node_put(np); |
|
} |
|
#else |
|
static void sysrq_of_get_keyreset_config(void) |
|
{ |
|
} |
|
#endif |
|
|
|
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_handle_keypress(struct sysrq_state *sysrq, |
|
unsigned int code, int value) |
|
{ |
|
bool was_active = sysrq->active; |
|
bool suppress; |
|
|
|
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_LEFTSHIFT: |
|
case KEY_RIGHTSHIFT: |
|
if (!value) |
|
sysrq->shift = KEY_RESERVED; |
|
else if (value != 2) |
|
sysrq->shift = code; |
|
break; |
|
|
|
case KEY_SYSRQ: |
|
if (value == 1 && sysrq->alt != KEY_RESERVED) { |
|
sysrq->active = true; |
|
sysrq->alt_use = sysrq->alt; |
|
/* either RESERVED (for released) or actual code */ |
|
sysrq->shift_use = sysrq->shift; |
|
/* |
|
* 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, sysrq->handle.dev->key); |
|
|
|
break; |
|
|
|
default: |
|
if (sysrq->active && value && value != 2) { |
|
unsigned char c = sysrq_xlate[code]; |
|
|
|
sysrq->need_reinject = false; |
|
if (sysrq->shift_use != KEY_RESERVED) |
|
c = toupper(c); |
|
__handle_sysrq(c, true); |
|
} |
|
break; |
|
} |
|
|
|
suppress = sysrq->active; |
|
|
|
if (!sysrq->active) { |
|
|
|
/* |
|
* See if reset sequence has changed since the last time. |
|
*/ |
|
if (sysrq->reset_seq_version != sysrq_reset_seq_version) |
|
sysrq_parse_reset_sequence(sysrq); |
|
|
|
/* |
|
* 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); |
|
|
|
/* Check for reset sequence */ |
|
sysrq_detect_reset_sequence(sysrq, code, value); |
|
|
|
} 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; |
|
} |
|
|
|
return suppress; |
|
} |
|
|
|
static bool sysrq_filter(struct input_handle *handle, |
|
unsigned int type, unsigned int code, int value) |
|
{ |
|
struct sysrq_state *sysrq = handle->private; |
|
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: |
|
suppress = sysrq_handle_keypress(sysrq, code, value); |
|
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; |
|
timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
|
|
|
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); |
|
del_timer_sync(&sysrq->keyreset_timer); |
|
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_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
|
.keybit = { [BIT_WORD(KEY_LEFTALT)] = 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 inline void sysrq_register_handler(void) |
|
{ |
|
int error; |
|
|
|
sysrq_of_get_keyreset_config(); |
|
|
|
error = input_register_handler(&sysrq_handler); |
|
if (error) |
|
pr_err("Failed to register input handler, error %d", error); |
|
} |
|
|
|
static inline void sysrq_unregister_handler(void) |
|
{ |
|
input_unregister_handler(&sysrq_handler); |
|
} |
|
|
|
static int sysrq_reset_seq_param_set(const char *buffer, |
|
const struct kernel_param *kp) |
|
{ |
|
unsigned long val; |
|
int error; |
|
|
|
error = kstrtoul(buffer, 0, &val); |
|
if (error < 0) |
|
return error; |
|
|
|
if (val > KEY_MAX) |
|
return -EINVAL; |
|
|
|
*((unsigned short *)kp->arg) = val; |
|
sysrq_reset_seq_version++; |
|
|
|
return 0; |
|
} |
|
|
|
static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
|
.get = param_get_ushort, |
|
.set = sysrq_reset_seq_param_set, |
|
}; |
|
|
|
#define param_check_sysrq_reset_seq(name, p) \ |
|
__param_check(name, p, unsigned short) |
|
|
|
/* |
|
* not really modular, but the easiest way to keep compat with existing |
|
* bootargs behaviour is to continue using module_param here. |
|
*/ |
|
module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
|
&sysrq_reset_seq_len, 0644); |
|
|
|
module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
|
|
|
#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; |
|
} |
|
EXPORT_SYMBOL_GPL(sysrq_toggle_support); |
|
|
|
static int __sysrq_swap_key_ops(int key, const struct sysrq_key_op *insert_op_p, |
|
const struct sysrq_key_op *remove_op_p) |
|
{ |
|
int retval; |
|
|
|
spin_lock(&sysrq_key_table_lock); |
|
if (__sysrq_get_key_op(key) == remove_op_p) { |
|
__sysrq_put_key_op(key, insert_op_p); |
|
retval = 0; |
|
} else { |
|
retval = -1; |
|
} |
|
spin_unlock(&sysrq_key_table_lock); |
|
|
|
/* |
|
* A concurrent __handle_sysrq either got the old op or the new op. |
|
* Wait for it to go away before returning, so the code for an old |
|
* op is not freed (eg. on module unload) while it is in use. |
|
*/ |
|
synchronize_rcu(); |
|
|
|
return retval; |
|
} |
|
|
|
int register_sysrq_key(int key, const 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, const 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 proc_ops sysrq_trigger_proc_ops = { |
|
.proc_write = write_sysrq_trigger, |
|
.proc_lseek = noop_llseek, |
|
}; |
|
|
|
static void sysrq_init_procfs(void) |
|
{ |
|
if (!proc_create("sysrq-trigger", S_IWUSR, NULL, |
|
&sysrq_trigger_proc_ops)) |
|
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; |
|
} |
|
device_initcall(sysrq_init);
|
|
|