| 1 | /* |
| 2 | * Linux Magic System Request Key Hacks |
| 3 | * |
| 4 | * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> |
| 5 | * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> |
| 6 | * |
| 7 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> |
| 8 | * overhauled to use key registration |
| 9 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies |
| 10 | * |
| 11 | * Copyright (c) 2010 Dmitry Torokhov |
| 12 | * Input handler conversion |
| 13 | */ |
| 14 | |
| 15 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 16 | |
| 17 | #include <linux/sched.h> |
| 18 | #include <linux/sched/rt.h> |
| 19 | #include <linux/interrupt.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/mount.h> |
| 23 | #include <linux/kdev_t.h> |
| 24 | #include <linux/major.h> |
| 25 | #include <linux/reboot.h> |
| 26 | #include <linux/sysrq.h> |
| 27 | #include <linux/kbd_kern.h> |
| 28 | #include <linux/proc_fs.h> |
| 29 | #include <linux/nmi.h> |
| 30 | #include <linux/quotaops.h> |
| 31 | #include <linux/perf_event.h> |
| 32 | #include <linux/kernel.h> |
| 33 | #include <linux/module.h> |
| 34 | #include <linux/suspend.h> |
| 35 | #include <linux/writeback.h> |
| 36 | #include <linux/swap.h> |
| 37 | #include <linux/spinlock.h> |
| 38 | #include <linux/vt_kern.h> |
| 39 | #include <linux/workqueue.h> |
| 40 | #include <linux/hrtimer.h> |
| 41 | #include <linux/oom.h> |
| 42 | #include <linux/slab.h> |
| 43 | #include <linux/input.h> |
| 44 | #include <linux/uaccess.h> |
| 45 | #include <linux/moduleparam.h> |
| 46 | #include <linux/jiffies.h> |
| 47 | |
| 48 | #include <asm/ptrace.h> |
| 49 | #include <asm/irq_regs.h> |
| 50 | |
| 51 | /* Whether we react on sysrq keys or just ignore them */ |
| 52 | static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; |
| 53 | static bool __read_mostly sysrq_always_enabled; |
| 54 | |
| 55 | unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED }; |
| 56 | int sysrq_reset_downtime_ms __weak; |
| 57 | |
| 58 | static bool sysrq_on(void) |
| 59 | { |
| 60 | return sysrq_enabled || sysrq_always_enabled; |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * A value of 1 means 'all', other nonzero values are an op mask: |
| 65 | */ |
| 66 | static bool sysrq_on_mask(int mask) |
| 67 | { |
| 68 | return sysrq_always_enabled || |
| 69 | sysrq_enabled == 1 || |
| 70 | (sysrq_enabled & mask); |
| 71 | } |
| 72 | |
| 73 | static int __init sysrq_always_enabled_setup(char *str) |
| 74 | { |
| 75 | sysrq_always_enabled = true; |
| 76 | pr_info("sysrq always enabled.\n"); |
| 77 | |
| 78 | return 1; |
| 79 | } |
| 80 | |
| 81 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); |
| 82 | |
| 83 | |
| 84 | static void sysrq_handle_loglevel(int key) |
| 85 | { |
| 86 | int i; |
| 87 | |
| 88 | i = key - '0'; |
| 89 | console_loglevel = 7; |
| 90 | printk("Loglevel set to %d\n", i); |
| 91 | console_loglevel = i; |
| 92 | } |
| 93 | static struct sysrq_key_op sysrq_loglevel_op = { |
| 94 | .handler = sysrq_handle_loglevel, |
| 95 | .help_msg = "loglevel(0-9)", |
| 96 | .action_msg = "Changing Loglevel", |
| 97 | .enable_mask = SYSRQ_ENABLE_LOG, |
| 98 | }; |
| 99 | |
| 100 | #ifdef CONFIG_VT |
| 101 | static void sysrq_handle_SAK(int key) |
| 102 | { |
| 103 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
| 104 | schedule_work(SAK_work); |
| 105 | } |
| 106 | static struct sysrq_key_op sysrq_SAK_op = { |
| 107 | .handler = sysrq_handle_SAK, |
| 108 | .help_msg = "sak(k)", |
| 109 | .action_msg = "SAK", |
| 110 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
| 111 | }; |
| 112 | #else |
| 113 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
| 114 | #endif |
| 115 | |
| 116 | #ifdef CONFIG_VT |
| 117 | static void sysrq_handle_unraw(int key) |
| 118 | { |
| 119 | vt_reset_unicode(fg_console); |
| 120 | } |
| 121 | |
| 122 | static struct sysrq_key_op sysrq_unraw_op = { |
| 123 | .handler = sysrq_handle_unraw, |
| 124 | .help_msg = "unraw(r)", |
| 125 | .action_msg = "Keyboard mode set to system default", |
| 126 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
| 127 | }; |
| 128 | #else |
| 129 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
| 130 | #endif /* CONFIG_VT */ |
| 131 | |
| 132 | static void sysrq_handle_crash(int key) |
| 133 | { |
| 134 | char *killer = NULL; |
| 135 | |
| 136 | panic_on_oops = 1; /* force panic */ |
| 137 | wmb(); |
| 138 | *killer = 1; |
| 139 | } |
| 140 | static struct sysrq_key_op sysrq_crash_op = { |
| 141 | .handler = sysrq_handle_crash, |
| 142 | .help_msg = "crash(c)", |
| 143 | .action_msg = "Trigger a crash", |
| 144 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 145 | }; |
| 146 | |
| 147 | static void sysrq_handle_reboot(int key) |
| 148 | { |
| 149 | lockdep_off(); |
| 150 | local_irq_enable(); |
| 151 | emergency_restart(); |
| 152 | } |
| 153 | static struct sysrq_key_op sysrq_reboot_op = { |
| 154 | .handler = sysrq_handle_reboot, |
| 155 | .help_msg = "reboot(b)", |
| 156 | .action_msg = "Resetting", |
| 157 | .enable_mask = SYSRQ_ENABLE_BOOT, |
| 158 | }; |
| 159 | |
| 160 | static void sysrq_handle_sync(int key) |
| 161 | { |
| 162 | emergency_sync(); |
| 163 | } |
| 164 | static struct sysrq_key_op sysrq_sync_op = { |
| 165 | .handler = sysrq_handle_sync, |
| 166 | .help_msg = "sync(s)", |
| 167 | .action_msg = "Emergency Sync", |
| 168 | .enable_mask = SYSRQ_ENABLE_SYNC, |
| 169 | }; |
| 170 | |
| 171 | static void sysrq_handle_show_timers(int key) |
| 172 | { |
| 173 | sysrq_timer_list_show(); |
| 174 | } |
| 175 | |
| 176 | static struct sysrq_key_op sysrq_show_timers_op = { |
| 177 | .handler = sysrq_handle_show_timers, |
| 178 | .help_msg = "show-all-timers(q)", |
| 179 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
| 180 | }; |
| 181 | |
| 182 | static void sysrq_handle_mountro(int key) |
| 183 | { |
| 184 | emergency_remount(); |
| 185 | } |
| 186 | static struct sysrq_key_op sysrq_mountro_op = { |
| 187 | .handler = sysrq_handle_mountro, |
| 188 | .help_msg = "unmount(u)", |
| 189 | .action_msg = "Emergency Remount R/O", |
| 190 | .enable_mask = SYSRQ_ENABLE_REMOUNT, |
| 191 | }; |
| 192 | |
| 193 | #ifdef CONFIG_LOCKDEP |
| 194 | static void sysrq_handle_showlocks(int key) |
| 195 | { |
| 196 | debug_show_all_locks(); |
| 197 | } |
| 198 | |
| 199 | static struct sysrq_key_op sysrq_showlocks_op = { |
| 200 | .handler = sysrq_handle_showlocks, |
| 201 | .help_msg = "show-all-locks(d)", |
| 202 | .action_msg = "Show Locks Held", |
| 203 | }; |
| 204 | #else |
| 205 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
| 206 | #endif |
| 207 | |
| 208 | #ifdef CONFIG_SMP |
| 209 | static DEFINE_SPINLOCK(show_lock); |
| 210 | |
| 211 | static void showacpu(void *dummy) |
| 212 | { |
| 213 | unsigned long flags; |
| 214 | |
| 215 | /* Idle CPUs have no interesting backtrace. */ |
| 216 | if (idle_cpu(smp_processor_id())) |
| 217 | return; |
| 218 | |
| 219 | spin_lock_irqsave(&show_lock, flags); |
| 220 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); |
| 221 | show_stack(NULL, NULL); |
| 222 | spin_unlock_irqrestore(&show_lock, flags); |
| 223 | } |
| 224 | |
| 225 | static void sysrq_showregs_othercpus(struct work_struct *dummy) |
| 226 | { |
| 227 | smp_call_function(showacpu, NULL, 0); |
| 228 | } |
| 229 | |
| 230 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); |
| 231 | |
| 232 | static void sysrq_handle_showallcpus(int key) |
| 233 | { |
| 234 | /* |
| 235 | * Fall back to the workqueue based printing if the |
| 236 | * backtrace printing did not succeed or the |
| 237 | * architecture has no support for it: |
| 238 | */ |
| 239 | if (!trigger_all_cpu_backtrace()) { |
| 240 | struct pt_regs *regs = get_irq_regs(); |
| 241 | |
| 242 | if (regs) { |
| 243 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); |
| 244 | show_regs(regs); |
| 245 | } |
| 246 | schedule_work(&sysrq_showallcpus); |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | static struct sysrq_key_op sysrq_showallcpus_op = { |
| 251 | .handler = sysrq_handle_showallcpus, |
| 252 | .help_msg = "show-backtrace-all-active-cpus(l)", |
| 253 | .action_msg = "Show backtrace of all active CPUs", |
| 254 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 255 | }; |
| 256 | #endif |
| 257 | |
| 258 | static void sysrq_handle_showregs(int key) |
| 259 | { |
| 260 | struct pt_regs *regs = get_irq_regs(); |
| 261 | if (regs) |
| 262 | show_regs(regs); |
| 263 | perf_event_print_debug(); |
| 264 | } |
| 265 | static struct sysrq_key_op sysrq_showregs_op = { |
| 266 | .handler = sysrq_handle_showregs, |
| 267 | .help_msg = "show-registers(p)", |
| 268 | .action_msg = "Show Regs", |
| 269 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 270 | }; |
| 271 | |
| 272 | static void sysrq_handle_showstate(int key) |
| 273 | { |
| 274 | show_state(); |
| 275 | } |
| 276 | static struct sysrq_key_op sysrq_showstate_op = { |
| 277 | .handler = sysrq_handle_showstate, |
| 278 | .help_msg = "show-task-states(t)", |
| 279 | .action_msg = "Show State", |
| 280 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 281 | }; |
| 282 | |
| 283 | static void sysrq_handle_showstate_blocked(int key) |
| 284 | { |
| 285 | show_state_filter(TASK_UNINTERRUPTIBLE); |
| 286 | } |
| 287 | static struct sysrq_key_op sysrq_showstate_blocked_op = { |
| 288 | .handler = sysrq_handle_showstate_blocked, |
| 289 | .help_msg = "show-blocked-tasks(w)", |
| 290 | .action_msg = "Show Blocked State", |
| 291 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 292 | }; |
| 293 | |
| 294 | #ifdef CONFIG_TRACING |
| 295 | #include <linux/ftrace.h> |
| 296 | |
| 297 | static void sysrq_ftrace_dump(int key) |
| 298 | { |
| 299 | ftrace_dump(DUMP_ALL); |
| 300 | } |
| 301 | static struct sysrq_key_op sysrq_ftrace_dump_op = { |
| 302 | .handler = sysrq_ftrace_dump, |
| 303 | .help_msg = "dump-ftrace-buffer(z)", |
| 304 | .action_msg = "Dump ftrace buffer", |
| 305 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 306 | }; |
| 307 | #else |
| 308 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
| 309 | #endif |
| 310 | |
| 311 | static void sysrq_handle_showmem(int key) |
| 312 | { |
| 313 | show_mem(0); |
| 314 | } |
| 315 | static struct sysrq_key_op sysrq_showmem_op = { |
| 316 | .handler = sysrq_handle_showmem, |
| 317 | .help_msg = "show-memory-usage(m)", |
| 318 | .action_msg = "Show Memory", |
| 319 | .enable_mask = SYSRQ_ENABLE_DUMP, |
| 320 | }; |
| 321 | |
| 322 | /* |
| 323 | * Signal sysrq helper function. Sends a signal to all user processes. |
| 324 | */ |
| 325 | static void send_sig_all(int sig) |
| 326 | { |
| 327 | struct task_struct *p; |
| 328 | |
| 329 | read_lock(&tasklist_lock); |
| 330 | for_each_process(p) { |
| 331 | if (p->flags & PF_KTHREAD) |
| 332 | continue; |
| 333 | if (is_global_init(p)) |
| 334 | continue; |
| 335 | |
| 336 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
| 337 | } |
| 338 | read_unlock(&tasklist_lock); |
| 339 | } |
| 340 | |
| 341 | static void sysrq_handle_term(int key) |
| 342 | { |
| 343 | send_sig_all(SIGTERM); |
| 344 | console_loglevel = 8; |
| 345 | } |
| 346 | static struct sysrq_key_op sysrq_term_op = { |
| 347 | .handler = sysrq_handle_term, |
| 348 | .help_msg = "terminate-all-tasks(e)", |
| 349 | .action_msg = "Terminate All Tasks", |
| 350 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
| 351 | }; |
| 352 | |
| 353 | static void moom_callback(struct work_struct *ignored) |
| 354 | { |
| 355 | out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL, |
| 356 | 0, NULL, true); |
| 357 | } |
| 358 | |
| 359 | static DECLARE_WORK(moom_work, moom_callback); |
| 360 | |
| 361 | static void sysrq_handle_moom(int key) |
| 362 | { |
| 363 | schedule_work(&moom_work); |
| 364 | } |
| 365 | static struct sysrq_key_op sysrq_moom_op = { |
| 366 | .handler = sysrq_handle_moom, |
| 367 | .help_msg = "memory-full-oom-kill(f)", |
| 368 | .action_msg = "Manual OOM execution", |
| 369 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
| 370 | }; |
| 371 | |
| 372 | #ifdef CONFIG_BLOCK |
| 373 | static void sysrq_handle_thaw(int key) |
| 374 | { |
| 375 | emergency_thaw_all(); |
| 376 | } |
| 377 | static struct sysrq_key_op sysrq_thaw_op = { |
| 378 | .handler = sysrq_handle_thaw, |
| 379 | .help_msg = "thaw-filesystems(j)", |
| 380 | .action_msg = "Emergency Thaw of all frozen filesystems", |
| 381 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
| 382 | }; |
| 383 | #endif |
| 384 | |
| 385 | static void sysrq_handle_kill(int key) |
| 386 | { |
| 387 | send_sig_all(SIGKILL); |
| 388 | console_loglevel = 8; |
| 389 | } |
| 390 | static struct sysrq_key_op sysrq_kill_op = { |
| 391 | .handler = sysrq_handle_kill, |
| 392 | .help_msg = "kill-all-tasks(i)", |
| 393 | .action_msg = "Kill All Tasks", |
| 394 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
| 395 | }; |
| 396 | |
| 397 | static void sysrq_handle_unrt(int key) |
| 398 | { |
| 399 | normalize_rt_tasks(); |
| 400 | } |
| 401 | static struct sysrq_key_op sysrq_unrt_op = { |
| 402 | .handler = sysrq_handle_unrt, |
| 403 | .help_msg = "nice-all-RT-tasks(n)", |
| 404 | .action_msg = "Nice All RT Tasks", |
| 405 | .enable_mask = SYSRQ_ENABLE_RTNICE, |
| 406 | }; |
| 407 | |
| 408 | /* Key Operations table and lock */ |
| 409 | static DEFINE_SPINLOCK(sysrq_key_table_lock); |
| 410 | |
| 411 | static struct sysrq_key_op *sysrq_key_table[36] = { |
| 412 | &sysrq_loglevel_op, /* 0 */ |
| 413 | &sysrq_loglevel_op, /* 1 */ |
| 414 | &sysrq_loglevel_op, /* 2 */ |
| 415 | &sysrq_loglevel_op, /* 3 */ |
| 416 | &sysrq_loglevel_op, /* 4 */ |
| 417 | &sysrq_loglevel_op, /* 5 */ |
| 418 | &sysrq_loglevel_op, /* 6 */ |
| 419 | &sysrq_loglevel_op, /* 7 */ |
| 420 | &sysrq_loglevel_op, /* 8 */ |
| 421 | &sysrq_loglevel_op, /* 9 */ |
| 422 | |
| 423 | /* |
| 424 | * a: Don't use for system provided sysrqs, it is handled specially on |
| 425 | * sparc and will never arrive. |
| 426 | */ |
| 427 | NULL, /* a */ |
| 428 | &sysrq_reboot_op, /* b */ |
| 429 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
| 430 | &sysrq_showlocks_op, /* d */ |
| 431 | &sysrq_term_op, /* e */ |
| 432 | &sysrq_moom_op, /* f */ |
| 433 | /* g: May be registered for the kernel debugger */ |
| 434 | NULL, /* g */ |
| 435 | NULL, /* h - reserved for help */ |
| 436 | &sysrq_kill_op, /* i */ |
| 437 | #ifdef CONFIG_BLOCK |
| 438 | &sysrq_thaw_op, /* j */ |
| 439 | #else |
| 440 | NULL, /* j */ |
| 441 | #endif |
| 442 | &sysrq_SAK_op, /* k */ |
| 443 | #ifdef CONFIG_SMP |
| 444 | &sysrq_showallcpus_op, /* l */ |
| 445 | #else |
| 446 | NULL, /* l */ |
| 447 | #endif |
| 448 | &sysrq_showmem_op, /* m */ |
| 449 | &sysrq_unrt_op, /* n */ |
| 450 | /* o: This will often be registered as 'Off' at init time */ |
| 451 | NULL, /* o */ |
| 452 | &sysrq_showregs_op, /* p */ |
| 453 | &sysrq_show_timers_op, /* q */ |
| 454 | &sysrq_unraw_op, /* r */ |
| 455 | &sysrq_sync_op, /* s */ |
| 456 | &sysrq_showstate_op, /* t */ |
| 457 | &sysrq_mountro_op, /* u */ |
| 458 | /* v: May be registered for frame buffer console restore */ |
| 459 | NULL, /* v */ |
| 460 | &sysrq_showstate_blocked_op, /* w */ |
| 461 | /* x: May be registered on ppc/powerpc for xmon */ |
| 462 | /* x: May be registered on sparc64 for global PMU dump */ |
| 463 | NULL, /* x */ |
| 464 | /* y: May be registered on sparc64 for global register dump */ |
| 465 | NULL, /* y */ |
| 466 | &sysrq_ftrace_dump_op, /* z */ |
| 467 | }; |
| 468 | |
| 469 | /* key2index calculation, -1 on invalid index */ |
| 470 | static int sysrq_key_table_key2index(int key) |
| 471 | { |
| 472 | int retval; |
| 473 | |
| 474 | if ((key >= '0') && (key <= '9')) |
| 475 | retval = key - '0'; |
| 476 | else if ((key >= 'a') && (key <= 'z')) |
| 477 | retval = key + 10 - 'a'; |
| 478 | else |
| 479 | retval = -1; |
| 480 | return retval; |
| 481 | } |
| 482 | |
| 483 | /* |
| 484 | * get and put functions for the table, exposed to modules. |
| 485 | */ |
| 486 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
| 487 | { |
| 488 | struct sysrq_key_op *op_p = NULL; |
| 489 | int i; |
| 490 | |
| 491 | i = sysrq_key_table_key2index(key); |
| 492 | if (i != -1) |
| 493 | op_p = sysrq_key_table[i]; |
| 494 | |
| 495 | return op_p; |
| 496 | } |
| 497 | |
| 498 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
| 499 | { |
| 500 | int i = sysrq_key_table_key2index(key); |
| 501 | |
| 502 | if (i != -1) |
| 503 | sysrq_key_table[i] = op_p; |
| 504 | } |
| 505 | |
| 506 | void __handle_sysrq(int key, bool check_mask) |
| 507 | { |
| 508 | struct sysrq_key_op *op_p; |
| 509 | int orig_log_level; |
| 510 | int i; |
| 511 | unsigned long flags; |
| 512 | |
| 513 | spin_lock_irqsave(&sysrq_key_table_lock, flags); |
| 514 | /* |
| 515 | * Raise the apparent loglevel to maximum so that the sysrq header |
| 516 | * is shown to provide the user with positive feedback. We do not |
| 517 | * simply emit this at KERN_EMERG as that would change message |
| 518 | * routing in the consumers of /proc/kmsg. |
| 519 | */ |
| 520 | orig_log_level = console_loglevel; |
| 521 | console_loglevel = 7; |
| 522 | printk(KERN_INFO "SysRq : "); |
| 523 | |
| 524 | op_p = __sysrq_get_key_op(key); |
| 525 | if (op_p) { |
| 526 | /* |
| 527 | * Should we check for enabled operations (/proc/sysrq-trigger |
| 528 | * should not) and is the invoked operation enabled? |
| 529 | */ |
| 530 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
| 531 | printk("%s\n", op_p->action_msg); |
| 532 | console_loglevel = orig_log_level; |
| 533 | op_p->handler(key); |
| 534 | } else { |
| 535 | printk("This sysrq operation is disabled.\n"); |
| 536 | } |
| 537 | } else { |
| 538 | printk("HELP : "); |
| 539 | /* Only print the help msg once per handler */ |
| 540 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
| 541 | if (sysrq_key_table[i]) { |
| 542 | int j; |
| 543 | |
| 544 | for (j = 0; sysrq_key_table[i] != |
| 545 | sysrq_key_table[j]; j++) |
| 546 | ; |
| 547 | if (j != i) |
| 548 | continue; |
| 549 | printk("%s ", sysrq_key_table[i]->help_msg); |
| 550 | } |
| 551 | } |
| 552 | printk("\n"); |
| 553 | console_loglevel = orig_log_level; |
| 554 | } |
| 555 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); |
| 556 | } |
| 557 | |
| 558 | void handle_sysrq(int key) |
| 559 | { |
| 560 | if (sysrq_on()) |
| 561 | __handle_sysrq(key, true); |
| 562 | } |
| 563 | EXPORT_SYMBOL(handle_sysrq); |
| 564 | |
| 565 | #ifdef CONFIG_INPUT |
| 566 | |
| 567 | /* Simple translation table for the SysRq keys */ |
| 568 | static const unsigned char sysrq_xlate[KEY_CNT] = |
| 569 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
| 570 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ |
| 571 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ |
| 572 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ |
| 573 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ |
| 574 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ |
| 575 | "\r\000/"; /* 0x60 - 0x6f */ |
| 576 | |
| 577 | struct sysrq_state { |
| 578 | struct input_handle handle; |
| 579 | struct work_struct reinject_work; |
| 580 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; |
| 581 | unsigned int alt; |
| 582 | unsigned int alt_use; |
| 583 | bool active; |
| 584 | bool need_reinject; |
| 585 | bool reinjecting; |
| 586 | |
| 587 | /* reset sequence handling */ |
| 588 | bool reset_canceled; |
| 589 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
| 590 | int reset_seq_len; |
| 591 | int reset_seq_cnt; |
| 592 | int reset_seq_version; |
| 593 | struct timer_list keyreset_timer; |
| 594 | }; |
| 595 | |
| 596 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
| 597 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; |
| 598 | static unsigned int sysrq_reset_seq_len; |
| 599 | static unsigned int sysrq_reset_seq_version = 1; |
| 600 | |
| 601 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) |
| 602 | { |
| 603 | int i; |
| 604 | unsigned short key; |
| 605 | |
| 606 | state->reset_seq_cnt = 0; |
| 607 | |
| 608 | for (i = 0; i < sysrq_reset_seq_len; i++) { |
| 609 | key = sysrq_reset_seq[i]; |
| 610 | |
| 611 | if (key == KEY_RESERVED || key > KEY_MAX) |
| 612 | break; |
| 613 | |
| 614 | __set_bit(key, state->reset_keybit); |
| 615 | state->reset_seq_len++; |
| 616 | |
| 617 | if (test_bit(key, state->key_down)) |
| 618 | state->reset_seq_cnt++; |
| 619 | } |
| 620 | |
| 621 | /* Disable reset until old keys are not released */ |
| 622 | state->reset_canceled = state->reset_seq_cnt != 0; |
| 623 | |
| 624 | state->reset_seq_version = sysrq_reset_seq_version; |
| 625 | } |
| 626 | |
| 627 | static void sysrq_do_reset(unsigned long dummy) |
| 628 | { |
| 629 | __handle_sysrq(sysrq_xlate[KEY_B], false); |
| 630 | } |
| 631 | |
| 632 | static void sysrq_handle_reset_request(struct sysrq_state *state) |
| 633 | { |
| 634 | if (sysrq_reset_downtime_ms) |
| 635 | mod_timer(&state->keyreset_timer, |
| 636 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); |
| 637 | else |
| 638 | sysrq_do_reset(0); |
| 639 | } |
| 640 | |
| 641 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, |
| 642 | unsigned int code, int value) |
| 643 | { |
| 644 | if (!test_bit(code, state->reset_keybit)) { |
| 645 | /* |
| 646 | * Pressing any key _not_ in reset sequence cancels |
| 647 | * the reset sequence. Also cancelling the timer in |
| 648 | * case additional keys were pressed after a reset |
| 649 | * has been requested. |
| 650 | */ |
| 651 | if (value && state->reset_seq_cnt) { |
| 652 | state->reset_canceled = true; |
| 653 | del_timer(&state->keyreset_timer); |
| 654 | } |
| 655 | } else if (value == 0) { |
| 656 | /* |
| 657 | * Key release - all keys in the reset sequence need |
| 658 | * to be pressed and held for the reset timeout |
| 659 | * to hold. |
| 660 | */ |
| 661 | del_timer(&state->keyreset_timer); |
| 662 | |
| 663 | if (--state->reset_seq_cnt == 0) |
| 664 | state->reset_canceled = false; |
| 665 | } else if (value == 1) { |
| 666 | /* key press, not autorepeat */ |
| 667 | if (++state->reset_seq_cnt == state->reset_seq_len && |
| 668 | !state->reset_canceled) { |
| 669 | sysrq_handle_reset_request(state); |
| 670 | } |
| 671 | } |
| 672 | } |
| 673 | |
| 674 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
| 675 | { |
| 676 | struct sysrq_state *sysrq = |
| 677 | container_of(work, struct sysrq_state, reinject_work); |
| 678 | struct input_handle *handle = &sysrq->handle; |
| 679 | unsigned int alt_code = sysrq->alt_use; |
| 680 | |
| 681 | if (sysrq->need_reinject) { |
| 682 | /* we do not want the assignment to be reordered */ |
| 683 | sysrq->reinjecting = true; |
| 684 | mb(); |
| 685 | |
| 686 | /* Simulate press and release of Alt + SysRq */ |
| 687 | input_inject_event(handle, EV_KEY, alt_code, 1); |
| 688 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); |
| 689 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); |
| 690 | |
| 691 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); |
| 692 | input_inject_event(handle, EV_KEY, alt_code, 0); |
| 693 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); |
| 694 | |
| 695 | mb(); |
| 696 | sysrq->reinjecting = false; |
| 697 | } |
| 698 | } |
| 699 | |
| 700 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
| 701 | unsigned int code, int value) |
| 702 | { |
| 703 | bool was_active = sysrq->active; |
| 704 | bool suppress; |
| 705 | |
| 706 | switch (code) { |
| 707 | |
| 708 | case KEY_LEFTALT: |
| 709 | case KEY_RIGHTALT: |
| 710 | if (!value) { |
| 711 | /* One of ALTs is being released */ |
| 712 | if (sysrq->active && code == sysrq->alt_use) |
| 713 | sysrq->active = false; |
| 714 | |
| 715 | sysrq->alt = KEY_RESERVED; |
| 716 | |
| 717 | } else if (value != 2) { |
| 718 | sysrq->alt = code; |
| 719 | sysrq->need_reinject = false; |
| 720 | } |
| 721 | break; |
| 722 | |
| 723 | case KEY_SYSRQ: |
| 724 | if (value == 1 && sysrq->alt != KEY_RESERVED) { |
| 725 | sysrq->active = true; |
| 726 | sysrq->alt_use = sysrq->alt; |
| 727 | /* |
| 728 | * If nothing else will be pressed we'll need |
| 729 | * to re-inject Alt-SysRq keysroke. |
| 730 | */ |
| 731 | sysrq->need_reinject = true; |
| 732 | } |
| 733 | |
| 734 | /* |
| 735 | * Pretend that sysrq was never pressed at all. This |
| 736 | * is needed to properly handle KGDB which will try |
| 737 | * to release all keys after exiting debugger. If we |
| 738 | * do not clear key bit it KGDB will end up sending |
| 739 | * release events for Alt and SysRq, potentially |
| 740 | * triggering print screen function. |
| 741 | */ |
| 742 | if (sysrq->active) |
| 743 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); |
| 744 | |
| 745 | break; |
| 746 | |
| 747 | default: |
| 748 | if (sysrq->active && value && value != 2) { |
| 749 | sysrq->need_reinject = false; |
| 750 | __handle_sysrq(sysrq_xlate[code], true); |
| 751 | } |
| 752 | break; |
| 753 | } |
| 754 | |
| 755 | suppress = sysrq->active; |
| 756 | |
| 757 | if (!sysrq->active) { |
| 758 | |
| 759 | /* |
| 760 | * See if reset sequence has changed since the last time. |
| 761 | */ |
| 762 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) |
| 763 | sysrq_parse_reset_sequence(sysrq); |
| 764 | |
| 765 | /* |
| 766 | * If we are not suppressing key presses keep track of |
| 767 | * keyboard state so we can release keys that have been |
| 768 | * pressed before entering SysRq mode. |
| 769 | */ |
| 770 | if (value) |
| 771 | set_bit(code, sysrq->key_down); |
| 772 | else |
| 773 | clear_bit(code, sysrq->key_down); |
| 774 | |
| 775 | if (was_active) |
| 776 | schedule_work(&sysrq->reinject_work); |
| 777 | |
| 778 | /* Check for reset sequence */ |
| 779 | sysrq_detect_reset_sequence(sysrq, code, value); |
| 780 | |
| 781 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
| 782 | /* |
| 783 | * Pass on release events for keys that was pressed before |
| 784 | * entering SysRq mode. |
| 785 | */ |
| 786 | suppress = false; |
| 787 | } |
| 788 | |
| 789 | return suppress; |
| 790 | } |
| 791 | |
| 792 | static bool sysrq_filter(struct input_handle *handle, |
| 793 | unsigned int type, unsigned int code, int value) |
| 794 | { |
| 795 | struct sysrq_state *sysrq = handle->private; |
| 796 | bool suppress; |
| 797 | |
| 798 | /* |
| 799 | * Do not filter anything if we are in the process of re-injecting |
| 800 | * Alt+SysRq combination. |
| 801 | */ |
| 802 | if (sysrq->reinjecting) |
| 803 | return false; |
| 804 | |
| 805 | switch (type) { |
| 806 | |
| 807 | case EV_SYN: |
| 808 | suppress = false; |
| 809 | break; |
| 810 | |
| 811 | case EV_KEY: |
| 812 | suppress = sysrq_handle_keypress(sysrq, code, value); |
| 813 | break; |
| 814 | |
| 815 | default: |
| 816 | suppress = sysrq->active; |
| 817 | break; |
| 818 | } |
| 819 | |
| 820 | return suppress; |
| 821 | } |
| 822 | |
| 823 | static int sysrq_connect(struct input_handler *handler, |
| 824 | struct input_dev *dev, |
| 825 | const struct input_device_id *id) |
| 826 | { |
| 827 | struct sysrq_state *sysrq; |
| 828 | int error; |
| 829 | |
| 830 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
| 831 | if (!sysrq) |
| 832 | return -ENOMEM; |
| 833 | |
| 834 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
| 835 | |
| 836 | sysrq->handle.dev = dev; |
| 837 | sysrq->handle.handler = handler; |
| 838 | sysrq->handle.name = "sysrq"; |
| 839 | sysrq->handle.private = sysrq; |
| 840 | setup_timer(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
| 841 | |
| 842 | error = input_register_handle(&sysrq->handle); |
| 843 | if (error) { |
| 844 | pr_err("Failed to register input sysrq handler, error %d\n", |
| 845 | error); |
| 846 | goto err_free; |
| 847 | } |
| 848 | |
| 849 | error = input_open_device(&sysrq->handle); |
| 850 | if (error) { |
| 851 | pr_err("Failed to open input device, error %d\n", error); |
| 852 | goto err_unregister; |
| 853 | } |
| 854 | |
| 855 | return 0; |
| 856 | |
| 857 | err_unregister: |
| 858 | input_unregister_handle(&sysrq->handle); |
| 859 | err_free: |
| 860 | kfree(sysrq); |
| 861 | return error; |
| 862 | } |
| 863 | |
| 864 | static void sysrq_disconnect(struct input_handle *handle) |
| 865 | { |
| 866 | struct sysrq_state *sysrq = handle->private; |
| 867 | |
| 868 | input_close_device(handle); |
| 869 | cancel_work_sync(&sysrq->reinject_work); |
| 870 | del_timer_sync(&sysrq->keyreset_timer); |
| 871 | input_unregister_handle(handle); |
| 872 | kfree(sysrq); |
| 873 | } |
| 874 | |
| 875 | /* |
| 876 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
| 877 | * keyboards have SysRq key predefined and so user may add it to keymap |
| 878 | * later, but we expect all such keyboards to have left alt. |
| 879 | */ |
| 880 | static const struct input_device_id sysrq_ids[] = { |
| 881 | { |
| 882 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | |
| 883 | INPUT_DEVICE_ID_MATCH_KEYBIT, |
| 884 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
| 885 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, |
| 886 | }, |
| 887 | { }, |
| 888 | }; |
| 889 | |
| 890 | static struct input_handler sysrq_handler = { |
| 891 | .filter = sysrq_filter, |
| 892 | .connect = sysrq_connect, |
| 893 | .disconnect = sysrq_disconnect, |
| 894 | .name = "sysrq", |
| 895 | .id_table = sysrq_ids, |
| 896 | }; |
| 897 | |
| 898 | static bool sysrq_handler_registered; |
| 899 | |
| 900 | static inline void sysrq_register_handler(void) |
| 901 | { |
| 902 | unsigned short key; |
| 903 | int error; |
| 904 | int i; |
| 905 | |
| 906 | for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) { |
| 907 | key = platform_sysrq_reset_seq[i]; |
| 908 | if (key == KEY_RESERVED || key > KEY_MAX) |
| 909 | break; |
| 910 | |
| 911 | sysrq_reset_seq[sysrq_reset_seq_len++] = key; |
| 912 | } |
| 913 | |
| 914 | error = input_register_handler(&sysrq_handler); |
| 915 | if (error) |
| 916 | pr_err("Failed to register input handler, error %d", error); |
| 917 | else |
| 918 | sysrq_handler_registered = true; |
| 919 | } |
| 920 | |
| 921 | static inline void sysrq_unregister_handler(void) |
| 922 | { |
| 923 | if (sysrq_handler_registered) { |
| 924 | input_unregister_handler(&sysrq_handler); |
| 925 | sysrq_handler_registered = false; |
| 926 | } |
| 927 | } |
| 928 | |
| 929 | static int sysrq_reset_seq_param_set(const char *buffer, |
| 930 | const struct kernel_param *kp) |
| 931 | { |
| 932 | unsigned long val; |
| 933 | int error; |
| 934 | |
| 935 | error = strict_strtoul(buffer, 0, &val); |
| 936 | if (error < 0) |
| 937 | return error; |
| 938 | |
| 939 | if (val > KEY_MAX) |
| 940 | return -EINVAL; |
| 941 | |
| 942 | *((unsigned short *)kp->arg) = val; |
| 943 | sysrq_reset_seq_version++; |
| 944 | |
| 945 | return 0; |
| 946 | } |
| 947 | |
| 948 | static struct kernel_param_ops param_ops_sysrq_reset_seq = { |
| 949 | .get = param_get_ushort, |
| 950 | .set = sysrq_reset_seq_param_set, |
| 951 | }; |
| 952 | |
| 953 | #define param_check_sysrq_reset_seq(name, p) \ |
| 954 | __param_check(name, p, unsigned short) |
| 955 | |
| 956 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
| 957 | &sysrq_reset_seq_len, 0644); |
| 958 | |
| 959 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
| 960 | |
| 961 | #else |
| 962 | |
| 963 | static inline void sysrq_register_handler(void) |
| 964 | { |
| 965 | } |
| 966 | |
| 967 | static inline void sysrq_unregister_handler(void) |
| 968 | { |
| 969 | } |
| 970 | |
| 971 | #endif /* CONFIG_INPUT */ |
| 972 | |
| 973 | int sysrq_toggle_support(int enable_mask) |
| 974 | { |
| 975 | bool was_enabled = sysrq_on(); |
| 976 | |
| 977 | sysrq_enabled = enable_mask; |
| 978 | |
| 979 | if (was_enabled != sysrq_on()) { |
| 980 | if (sysrq_on()) |
| 981 | sysrq_register_handler(); |
| 982 | else |
| 983 | sysrq_unregister_handler(); |
| 984 | } |
| 985 | |
| 986 | return 0; |
| 987 | } |
| 988 | |
| 989 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
| 990 | struct sysrq_key_op *remove_op_p) |
| 991 | { |
| 992 | int retval; |
| 993 | unsigned long flags; |
| 994 | |
| 995 | spin_lock_irqsave(&sysrq_key_table_lock, flags); |
| 996 | if (__sysrq_get_key_op(key) == remove_op_p) { |
| 997 | __sysrq_put_key_op(key, insert_op_p); |
| 998 | retval = 0; |
| 999 | } else { |
| 1000 | retval = -1; |
| 1001 | } |
| 1002 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); |
| 1003 | return retval; |
| 1004 | } |
| 1005 | |
| 1006 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) |
| 1007 | { |
| 1008 | return __sysrq_swap_key_ops(key, op_p, NULL); |
| 1009 | } |
| 1010 | EXPORT_SYMBOL(register_sysrq_key); |
| 1011 | |
| 1012 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) |
| 1013 | { |
| 1014 | return __sysrq_swap_key_ops(key, NULL, op_p); |
| 1015 | } |
| 1016 | EXPORT_SYMBOL(unregister_sysrq_key); |
| 1017 | |
| 1018 | #ifdef CONFIG_PROC_FS |
| 1019 | /* |
| 1020 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C |
| 1021 | */ |
| 1022 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, |
| 1023 | size_t count, loff_t *ppos) |
| 1024 | { |
| 1025 | if (count) { |
| 1026 | char c; |
| 1027 | |
| 1028 | if (get_user(c, buf)) |
| 1029 | return -EFAULT; |
| 1030 | __handle_sysrq(c, false); |
| 1031 | } |
| 1032 | |
| 1033 | return count; |
| 1034 | } |
| 1035 | |
| 1036 | static const struct file_operations proc_sysrq_trigger_operations = { |
| 1037 | .write = write_sysrq_trigger, |
| 1038 | .llseek = noop_llseek, |
| 1039 | }; |
| 1040 | |
| 1041 | static void sysrq_init_procfs(void) |
| 1042 | { |
| 1043 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, |
| 1044 | &proc_sysrq_trigger_operations)) |
| 1045 | pr_err("Failed to register proc interface\n"); |
| 1046 | } |
| 1047 | |
| 1048 | #else |
| 1049 | |
| 1050 | static inline void sysrq_init_procfs(void) |
| 1051 | { |
| 1052 | } |
| 1053 | |
| 1054 | #endif /* CONFIG_PROC_FS */ |
| 1055 | |
| 1056 | static int __init sysrq_init(void) |
| 1057 | { |
| 1058 | sysrq_init_procfs(); |
| 1059 | |
| 1060 | if (sysrq_on()) |
| 1061 | sysrq_register_handler(); |
| 1062 | |
| 1063 | return 0; |
| 1064 | } |
| 1065 | module_init(sysrq_init); |