906 lines
21 KiB
C
906 lines
21 KiB
C
/*
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* Linux Magic System Request Key Hacks
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*
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* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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* based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
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*
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* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
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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.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/buffer_head.h> /* for fsync_bdev() */
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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 <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 = 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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* 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 = 7;
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printk("Loglevel set to %d\n", i);
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console_loglevel = i;
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}
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static 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 struct sysrq_key_op sysrq_SAK_op = {
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.handler = sysrq_handle_SAK,
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.help_msg = "saK",
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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 (*(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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struct kbd_struct *kbd = &kbd_table[fg_console];
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if (kbd)
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kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
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}
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static struct sysrq_key_op sysrq_unraw_op = {
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.handler = sysrq_handle_unraw,
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.help_msg = "unRaw",
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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 (*(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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char *killer = NULL;
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panic_on_oops = 1; /* force panic */
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wmb();
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*killer = 1;
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}
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static struct sysrq_key_op sysrq_crash_op = {
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.handler = sysrq_handle_crash,
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.help_msg = "Crash",
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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 struct sysrq_key_op sysrq_reboot_op = {
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.handler = sysrq_handle_reboot,
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.help_msg = "reBoot",
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.action_msg = "Resetting",
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.enable_mask = SYSRQ_ENABLE_BOOT,
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};
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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 struct sysrq_key_op sysrq_sync_op = {
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.handler = sysrq_handle_sync,
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.help_msg = "Sync",
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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 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 struct sysrq_key_op sysrq_mountro_op = {
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.handler = sysrq_handle_mountro,
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.help_msg = "Unmount",
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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 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 (*(struct sysrq_key_op *)NULL)
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#endif
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#ifdef CONFIG_SMP
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static DEFINE_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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spin_lock_irqsave(&show_lock, flags);
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printk(KERN_INFO "CPU%d:\n", smp_processor_id());
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show_stack(NULL, NULL);
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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 = get_irq_regs();
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if (regs) {
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printk(KERN_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 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 = 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 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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}
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static 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 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 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 (*(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);
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}
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static 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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for_each_process(p) {
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if (p->mm && !is_global_init(p))
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/* Not swapper, init nor kernel thread */
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force_sig(sig, p);
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}
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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 = 8;
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}
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static 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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out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL);
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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 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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#ifdef CONFIG_BLOCK
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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 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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#endif
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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 = 8;
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}
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static 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 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 struct sysrq_key_op *sysrq_key_table[36] = {
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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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* 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 & ibm_emac driver debug */
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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 ppc/powerpc for xmon */
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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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};
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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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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
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retval = -1;
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return retval;
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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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struct sysrq_key_op *__sysrq_get_key_op(int key)
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{
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struct sysrq_key_op *op_p = NULL;
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int i;
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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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return op_p;
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}
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static void __sysrq_put_key_op(int key, 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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if (i != -1)
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sysrq_key_table[i] = op_p;
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}
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void __handle_sysrq(int key, bool check_mask)
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{
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struct sysrq_key_op *op_p;
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int orig_log_level;
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int i;
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unsigned long flags;
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spin_lock_irqsave(&sysrq_key_table_lock, flags);
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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
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* simply emit this at KERN_EMERG as that would change message
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* routing in the consumers of /proc/kmsg.
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*/
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orig_log_level = console_loglevel;
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console_loglevel = 7;
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printk(KERN_INFO "SysRq : ");
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op_p = __sysrq_get_key_op(key);
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if (op_p) {
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/*
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|
* 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);
|