LXR linux/include/linux/sysrq.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/* -*- linux-c -*-
   3 *
   4 *      $Id: sysrq.h,v 1.3 1997/07/17 11:54:33 mj Exp $
   5 *
   6 *      Linux Magic System Request Key Hacks
   7 *
   8 *      (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
   9 *
  10 *      (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
  11 *      overhauled to use key registration
  12 *      based upon discusions in irc://irc.openprojects.net/#kernelnewbies
  13 */
  14
  15#ifndef _LINUX_SYSRQ_H
  16#define _LINUX_SYSRQ_H
  17
  18#include <linux/errno.h>
  19#include <linux/types.h>
  20
  21/* Possible values of bitmask for enabling sysrq functions */
  22/* 0x0001 is reserved for enable everything */
  23#define SYSRQ_ENABLE_LOG        0x0002
  24#define SYSRQ_ENABLE_KEYBOARD   0x0004
  25#define SYSRQ_ENABLE_DUMP       0x0008
  26#define SYSRQ_ENABLE_SYNC       0x0010
  27#define SYSRQ_ENABLE_REMOUNT    0x0020
  28#define SYSRQ_ENABLE_SIGNAL     0x0040
  29#define SYSRQ_ENABLE_BOOT       0x0080
  30#define SYSRQ_ENABLE_RTNICE     0x0100
  31
  32struct sysrq_key_op {
  33        void (* const handler)(int);
  34        const char * const help_msg;
  35        const char * const action_msg;
  36        const int enable_mask;
  37};
  38
  39#ifdef CONFIG_MAGIC_SYSRQ
  40
  41/* Generic SysRq interface -- you may call it from any device driver, supplying
  42 * ASCII code of the key, pointer to registers and kbd/tty structs (if they
  43 * are available -- else NULL's).
  44 */
  45
  46void handle_sysrq(int key);
  47void __handle_sysrq(int key, bool check_mask);
  48int register_sysrq_key(int key, const struct sysrq_key_op *op);
  49int unregister_sysrq_key(int key, const struct sysrq_key_op *op);
  50extern const struct sysrq_key_op *__sysrq_reboot_op;
  51
  52int sysrq_toggle_support(int enable_mask);
  53int sysrq_mask(void);
  54
  55#else
  56
  57static inline void handle_sysrq(int key)
  58{
  59}
  60
  61static inline void __handle_sysrq(int key, bool check_mask)
  62{
  63}
  64
  65static inline int register_sysrq_key(int key, const struct sysrq_key_op *op)
  66{
  67        return -EINVAL;
  68}
  69
  70static inline int unregister_sysrq_key(int key, const struct sysrq_key_op *op)
  71{
  72        return -EINVAL;
  73}
  74
  75static inline int sysrq_mask(void)
  76{
  77        /* Magic SysRq disabled mask */
  78        return 0;
  79}
  80
  81#endif
  82
  83#endif /* _LINUX_SYSRQ_H */
  84