1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * hrtimers - High-resolution kernel timers 4 * 5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> 6 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar 7 * 8 * data type definitions, declarations, prototypes 9 * 10 * Started by: Thomas Gleixner and Ingo Molnar 11 */ 12 #ifndef _LINUX_HRTIMER_H 13 #define _LINUX_HRTIMER_H 14 15 #include <linux/hrtimer_defs.h> 16 #include <linux/rbtree.h> 17 #include <linux/init.h> 18 #include <linux/list.h> 19 #include <linux/percpu.h> 20 #include <linux/seqlock.h> 21 #include <linux/timer.h> 22 #include <linux/timerqueue.h> 23 24 struct hrtimer_clock_base; 25 struct hrtimer_cpu_base; 26 27 /* 28 * Mode arguments of xxx_hrtimer functions: 29 * 30 * HRTIMER_MODE_ABS - Time value is absolute 31 * HRTIMER_MODE_REL - Time value is relative to now 32 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered 33 * when starting the timer) 34 * HRTIMER_MODE_SOFT - Timer callback function will be executed in 35 * soft irq context 36 * HRTIMER_MODE_HARD - Timer callback function will be executed in 37 * hard irq context even on PREEMPT_RT. 38 */ 39 enum hrtimer_mode { 40 HRTIMER_MODE_ABS = 0x00, 41 HRTIMER_MODE_REL = 0x01, 42 HRTIMER_MODE_PINNED = 0x02, 43 HRTIMER_MODE_SOFT = 0x04, 44 HRTIMER_MODE_HARD = 0x08, 45 46 HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED, 47 HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED, 48 49 HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT, 50 HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT, 51 52 HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT, 53 HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT, 54 55 HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD, 56 HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD, 57 58 HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD, 59 HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD, 60 }; 61 62 /* 63 * Return values for the callback function 64 */ 65 enum hrtimer_restart { 66 HRTIMER_NORESTART, /* Timer is not restarted */ 67 HRTIMER_RESTART, /* Timer must be restarted */ 68 }; 69 70 /* 71 * Values to track state of the timer 72 * 73 * Possible states: 74 * 75 * 0x00 inactive 76 * 0x01 enqueued into rbtree 77 * 78 * The callback state is not part of the timer->state because clearing it would 79 * mean touching the timer after the callback, this makes it impossible to free 80 * the timer from the callback function. 81 * 82 * Therefore we track the callback state in: 83 * 84 * timer->base->cpu_base->running == timer 85 * 86 * On SMP it is possible to have a "callback function running and enqueued" 87 * status. It happens for example when a posix timer expired and the callback 88 * queued a signal. Between dropping the lock which protects the posix timer 89 * and reacquiring the base lock of the hrtimer, another CPU can deliver the 90 * signal and rearm the timer. 91 * 92 * All state transitions are protected by cpu_base->lock. 93 */ 94 #define HRTIMER_STATE_INACTIVE 0x00 95 #define HRTIMER_STATE_ENQUEUED 0x01 96 97 /** 98 * struct hrtimer - the basic hrtimer structure 99 * @node: timerqueue node, which also manages node.expires, 100 * the absolute expiry time in the hrtimers internal 101 * representation. The time is related to the clock on 102 * which the timer is based. Is setup by adding 103 * slack to the _softexpires value. For non range timers 104 * identical to _softexpires. 105 * @_softexpires: the absolute earliest expiry time of the hrtimer. 106 * The time which was given as expiry time when the timer 107 * was armed. 108 * @function: timer expiry callback function 109 * @base: pointer to the timer base (per cpu and per clock) 110 * @state: state information (See bit values above) 111 * @is_rel: Set if the timer was armed relative 112 * @is_soft: Set if hrtimer will be expired in soft interrupt context. 113 * @is_hard: Set if hrtimer will be expired in hard interrupt context 114 * even on RT. 115 * 116 * The hrtimer structure must be initialized by hrtimer_init() 117 */ 118 struct hrtimer { 119 struct timerqueue_node node; 120 ktime_t _softexpires; 121 enum hrtimer_restart (*function)(struct hrtimer *); 122 struct hrtimer_clock_base *base; 123 u8 state; 124 u8 is_rel; 125 u8 is_soft; 126 u8 is_hard; 127 }; 128 129 /** 130 * struct hrtimer_sleeper - simple sleeper structure 131 * @timer: embedded timer structure 132 * @task: task to wake up 133 * 134 * task is set to NULL, when the timer expires. 135 */ 136 struct hrtimer_sleeper { 137 struct hrtimer timer; 138 struct task_struct *task; 139 }; 140 141 #ifdef CONFIG_64BIT 142 # define __hrtimer_clock_base_align ____cacheline_aligned 143 #else 144 # define __hrtimer_clock_base_align 145 #endif 146 147 /** 148 * struct hrtimer_clock_base - the timer base for a specific clock 149 * @cpu_base: per cpu clock base 150 * @index: clock type index for per_cpu support when moving a 151 * timer to a base on another cpu. 152 * @clockid: clock id for per_cpu support 153 * @seq: seqcount around __run_hrtimer 154 * @running: pointer to the currently running hrtimer 155 * @active: red black tree root node for the active timers 156 * @get_time: function to retrieve the current time of the clock 157 * @offset: offset of this clock to the monotonic base 158 */ 159 struct hrtimer_clock_base { 160 struct hrtimer_cpu_base *cpu_base; 161 unsigned int index; 162 clockid_t clockid; 163 seqcount_raw_spinlock_t seq; 164 struct hrtimer *running; 165 struct timerqueue_head active; 166 ktime_t (*get_time)(void); 167 ktime_t offset; 168 } __hrtimer_clock_base_align; 169 170 enum hrtimer_base_type { 171 HRTIMER_BASE_MONOTONIC, 172 HRTIMER_BASE_REALTIME, 173 HRTIMER_BASE_BOOTTIME, 174 HRTIMER_BASE_TAI, 175 HRTIMER_BASE_MONOTONIC_SOFT, 176 HRTIMER_BASE_REALTIME_SOFT, 177 HRTIMER_BASE_BOOTTIME_SOFT, 178 HRTIMER_BASE_TAI_SOFT, 179 HRTIMER_MAX_CLOCK_BASES, 180 }; 181 182 /** 183 * struct hrtimer_cpu_base - the per cpu clock bases 184 * @lock: lock protecting the base and associated clock bases 185 * and timers 186 * @cpu: cpu number 187 * @active_bases: Bitfield to mark bases with active timers 188 * @clock_was_set_seq: Sequence counter of clock was set events 189 * @hres_active: State of high resolution mode 190 * @in_hrtirq: hrtimer_interrupt() is currently executing 191 * @hang_detected: The last hrtimer interrupt detected a hang 192 * @softirq_activated: displays, if the softirq is raised - update of softirq 193 * related settings is not required then. 194 * @nr_events: Total number of hrtimer interrupt events 195 * @nr_retries: Total number of hrtimer interrupt retries 196 * @nr_hangs: Total number of hrtimer interrupt hangs 197 * @max_hang_time: Maximum time spent in hrtimer_interrupt 198 * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are 199 * expired 200 * @timer_waiters: A hrtimer_cancel() invocation waits for the timer 201 * callback to finish. 202 * @expires_next: absolute time of the next event, is required for remote 203 * hrtimer enqueue; it is the total first expiry time (hard 204 * and soft hrtimer are taken into account) 205 * @next_timer: Pointer to the first expiring timer 206 * @softirq_expires_next: Time to check, if soft queues needs also to be expired 207 * @softirq_next_timer: Pointer to the first expiring softirq based timer 208 * @clock_base: array of clock bases for this cpu 209 * 210 * Note: next_timer is just an optimization for __remove_hrtimer(). 211 * Do not dereference the pointer because it is not reliable on 212 * cross cpu removals. 213 */ 214 struct hrtimer_cpu_base { 215 raw_spinlock_t lock; 216 unsigned int cpu; 217 unsigned int active_bases; 218 unsigned int clock_was_set_seq; 219 unsigned int hres_active : 1, 220 in_hrtirq : 1, 221 hang_detected : 1, 222 softirq_activated : 1; 223 #ifdef CONFIG_HIGH_RES_TIMERS 224 unsigned int nr_events; 225 unsigned short nr_retries; 226 unsigned short nr_hangs; 227 unsigned int max_hang_time; 228 #endif 229 #ifdef CONFIG_PREEMPT_RT 230 spinlock_t softirq_expiry_lock; 231 atomic_t timer_waiters; 232 #endif 233 ktime_t expires_next; 234 struct hrtimer *next_timer; 235 ktime_t softirq_expires_next; 236 struct hrtimer *softirq_next_timer; 237 struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; 238 } ____cacheline_aligned; 239 240 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) 241 { 242 timer->node.expires = time; 243 timer->_softexpires = time; 244 } 245 246 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) 247 { 248 timer->_softexpires = time; 249 timer->node.expires = ktime_add_safe(time, delta); 250 } 251 252 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta) 253 { 254 timer->_softexpires = time; 255 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); 256 } 257 258 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) 259 { 260 timer->node.expires = tv64; 261 timer->_softexpires = tv64; 262 } 263 264 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) 265 { 266 timer->node.expires = ktime_add_safe(timer->node.expires, time); 267 timer->_softexpires = ktime_add_safe(timer->_softexpires, time); 268 } 269 270 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) 271 { 272 timer->node.expires = ktime_add_ns(timer->node.expires, ns); 273 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); 274 } 275 276 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) 277 { 278 return timer->node.expires; 279 } 280 281 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) 282 { 283 return timer->_softexpires; 284 } 285 286 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) 287 { 288 return timer->node.expires; 289 } 290 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) 291 { 292 return timer->_softexpires; 293 } 294 295 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) 296 { 297 return ktime_to_ns(timer->node.expires); 298 } 299 300 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) 301 { 302 return ktime_sub(timer->node.expires, timer->base->get_time()); 303 } 304 305 static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) 306 { 307 return timer->base->get_time(); 308 } 309 310 static inline int hrtimer_is_hres_active(struct hrtimer *timer) 311 { 312 return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ? 313 timer->base->cpu_base->hres_active : 0; 314 } 315 316 #ifdef CONFIG_HIGH_RES_TIMERS 317 struct clock_event_device; 318 319 extern void hrtimer_interrupt(struct clock_event_device *dev); 320 321 extern void clock_was_set_delayed(void); 322 323 extern unsigned int hrtimer_resolution; 324 325 #else 326 327 #define hrtimer_resolution (unsigned int)LOW_RES_NSEC 328 329 static inline void clock_was_set_delayed(void) { } 330 331 #endif 332 333 static inline ktime_t 334 __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now) 335 { 336 ktime_t rem = ktime_sub(timer->node.expires, now); 337 338 /* 339 * Adjust relative timers for the extra we added in 340 * hrtimer_start_range_ns() to prevent short timeouts. 341 */ 342 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel) 343 rem -= hrtimer_resolution; 344 return rem; 345 } 346 347 static inline ktime_t 348 hrtimer_expires_remaining_adjusted(const struct hrtimer *timer) 349 { 350 return __hrtimer_expires_remaining_adjusted(timer, 351 timer->base->get_time()); 352 } 353 354 extern void clock_was_set(void); 355 #ifdef CONFIG_TIMERFD 356 extern void timerfd_clock_was_set(void); 357 #else 358 static inline void timerfd_clock_was_set(void) { } 359 #endif 360 extern void hrtimers_resume(void); 361 362 DECLARE_PER_CPU(struct tick_device, tick_cpu_device); 363 364 #ifdef CONFIG_PREEMPT_RT 365 void hrtimer_cancel_wait_running(const struct hrtimer *timer); 366 #else 367 static inline void hrtimer_cancel_wait_running(struct hrtimer *timer) 368 { 369 cpu_relax(); 370 } 371 #endif 372 373 /* Exported timer functions: */ 374 375 /* Initialize timers: */ 376 extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, 377 enum hrtimer_mode mode); 378 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id, 379 enum hrtimer_mode mode); 380 381 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS 382 extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock, 383 enum hrtimer_mode mode); 384 extern void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, 385 clockid_t clock_id, 386 enum hrtimer_mode mode); 387 388 extern void destroy_hrtimer_on_stack(struct hrtimer *timer); 389 #else 390 static inline void hrtimer_init_on_stack(struct hrtimer *timer, 391 clockid_t which_clock, 392 enum hrtimer_mode mode) 393 { 394 hrtimer_init(timer, which_clock, mode); 395 } 396 397 static inline void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl, 398 clockid_t clock_id, 399 enum hrtimer_mode mode) 400 { 401 hrtimer_init_sleeper(sl, clock_id, mode); 402 } 403 404 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } 405 #endif 406 407 /* Basic timer operations: */ 408 extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, 409 u64 range_ns, const enum hrtimer_mode mode); 410 411 /** 412 * hrtimer_start - (re)start an hrtimer 413 * @timer: the timer to be added 414 * @tim: expiry time 415 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or 416 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED); 417 * softirq based mode is considered for debug purpose only! 418 */ 419 static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim, 420 const enum hrtimer_mode mode) 421 { 422 hrtimer_start_range_ns(timer, tim, 0, mode); 423 } 424 425 extern int hrtimer_cancel(struct hrtimer *timer); 426 extern int hrtimer_try_to_cancel(struct hrtimer *timer); 427 428 static inline void hrtimer_start_expires(struct hrtimer *timer, 429 enum hrtimer_mode mode) 430 { 431 u64 delta; 432 ktime_t soft, hard; 433 soft = hrtimer_get_softexpires(timer); 434 hard = hrtimer_get_expires(timer); 435 delta = ktime_to_ns(ktime_sub(hard, soft)); 436 hrtimer_start_range_ns(timer, soft, delta, mode); 437 } 438 439 void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl, 440 enum hrtimer_mode mode); 441 442 static inline void hrtimer_restart(struct hrtimer *timer) 443 { 444 hrtimer_start_expires(timer, HRTIMER_MODE_ABS); 445 } 446 447 /* Query timers: */ 448 extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust); 449 450 /** 451 * hrtimer_get_remaining - get remaining time for the timer 452 * @timer: the timer to read 453 */ 454 static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) 455 { 456 return __hrtimer_get_remaining(timer, false); 457 } 458 459 extern u64 hrtimer_get_next_event(void); 460 extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); 461 462 extern bool hrtimer_active(const struct hrtimer *timer); 463 464 /** 465 * hrtimer_is_queued - check, whether the timer is on one of the queues 466 * @timer: Timer to check 467 * 468 * Returns: True if the timer is queued, false otherwise 469 * 470 * The function can be used lockless, but it gives only a current snapshot. 471 */ 472 static inline bool hrtimer_is_queued(struct hrtimer *timer) 473 { 474 /* The READ_ONCE pairs with the update functions of timer->state */ 475 return !!(READ_ONCE(timer->state) & HRTIMER_STATE_ENQUEUED); 476 } 477 478 /* 479 * Helper function to check, whether the timer is running the callback 480 * function 481 */ 482 static inline int hrtimer_callback_running(struct hrtimer *timer) 483 { 484 return timer->base->running == timer; 485 } 486 487 /* Forward a hrtimer so it expires after now: */ 488 extern u64 489 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 490 491 /** 492 * hrtimer_forward_now - forward the timer expiry so it expires after now 493 * @timer: hrtimer to forward 494 * @interval: the interval to forward 495 * 496 * Forward the timer expiry so it will expire after the current time 497 * of the hrtimer clock base. Returns the number of overruns. 498 * 499 * Can be safely called from the callback function of @timer. If 500 * called from other contexts @timer must neither be enqueued nor 501 * running the callback and the caller needs to take care of 502 * serialization. 503 * 504 * Note: This only updates the timer expiry value and does not requeue 505 * the timer. 506 */ 507 static inline u64 hrtimer_forward_now(struct hrtimer *timer, 508 ktime_t interval) 509 { 510 return hrtimer_forward(timer, timer->base->get_time(), interval); 511 } 512 513 /* Precise sleep: */ 514 515 extern int nanosleep_copyout(struct restart_block *, struct timespec64 *); 516 extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode, 517 const clockid_t clockid); 518 519 extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta, 520 const enum hrtimer_mode mode); 521 extern int schedule_hrtimeout_range_clock(ktime_t *expires, 522 u64 delta, 523 const enum hrtimer_mode mode, 524 clockid_t clock_id); 525 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); 526 527 /* Soft interrupt function to run the hrtimer queues: */ 528 extern void hrtimer_run_queues(void); 529 530 /* Bootup initialization: */ 531 extern void __init hrtimers_init(void); 532 533 /* Show pending timers: */ 534 extern void sysrq_timer_list_show(void); 535 536 int hrtimers_prepare_cpu(unsigned int cpu); 537 #ifdef CONFIG_HOTPLUG_CPU 538 int hrtimers_dead_cpu(unsigned int cpu); 539 #else 540 #define hrtimers_dead_cpu NULL 541 #endif 542 543 #endif 544