1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * hrtimers - High-resolution kernel timers 4 * 5 * Copyright(C) 2005, Linutronix GmbH, Thomas Gleixner <tglx@kernel.org> 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/hrtimer_rearm.h> 17 #include <linux/hrtimer_types.h> 18 #include <linux/init.h> 19 #include <linux/list.h> 20 #include <linux/percpu-defs.h> 21 #include <linux/rbtree.h> 22 #include <linux/timer.h> 23 24 /* 25 * Mode arguments of xxx_hrtimer functions: 26 * 27 * HRTIMER_MODE_ABS - Time value is absolute 28 * HRTIMER_MODE_REL - Time value is relative to now 29 * HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered 30 * when starting the timer) 31 * HRTIMER_MODE_SOFT - Timer callback function will be executed in 32 * soft irq context 33 * HRTIMER_MODE_HARD - Timer callback function will be executed in 34 * hard irq context even on PREEMPT_RT. 35 * HRTIMER_MODE_LAZY_REARM - Avoid reprogramming if the timer was the 36 * first expiring timer and is moved into the 37 * future. Special mode for the HRTICK timer to 38 * avoid extensive reprogramming of the hardware, 39 * which is expensive in virtual machines. Risks 40 * a pointless expiry, but that's better than 41 * reprogramming on every context switch, 42 */ 43 enum hrtimer_mode { 44 HRTIMER_MODE_ABS = 0x00, 45 HRTIMER_MODE_REL = 0x01, 46 HRTIMER_MODE_PINNED = 0x02, 47 HRTIMER_MODE_SOFT = 0x04, 48 HRTIMER_MODE_HARD = 0x08, 49 HRTIMER_MODE_LAZY_REARM = 0x10, 50 51 HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED, 52 HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED, 53 54 HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT, 55 HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT, 56 57 HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT, 58 HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT, 59 60 HRTIMER_MODE_ABS_HARD = HRTIMER_MODE_ABS | HRTIMER_MODE_HARD, 61 HRTIMER_MODE_REL_HARD = HRTIMER_MODE_REL | HRTIMER_MODE_HARD, 62 63 HRTIMER_MODE_ABS_PINNED_HARD = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_HARD, 64 HRTIMER_MODE_REL_PINNED_HARD = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_HARD, 65 }; 66 67 /** 68 * struct hrtimer_sleeper - simple sleeper structure 69 * @timer: embedded timer structure 70 * @task: task to wake up 71 * 72 * task is set to NULL, when the timer expires. 73 */ 74 struct hrtimer_sleeper { 75 struct hrtimer timer; 76 struct task_struct *task; 77 }; 78 79 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) 80 { 81 timer->node.expires = time; 82 timer->_softexpires = time; 83 } 84 85 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta) 86 { 87 timer->_softexpires = time; 88 timer->node.expires = ktime_add_safe(time, delta); 89 } 90 91 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, u64 delta) 92 { 93 timer->_softexpires = time; 94 timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta)); 95 } 96 97 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) 98 { 99 timer->node.expires = ktime_add_safe(timer->node.expires, time); 100 timer->_softexpires = ktime_add_safe(timer->_softexpires, time); 101 } 102 103 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns) 104 { 105 timer->node.expires = ktime_add_ns(timer->node.expires, ns); 106 timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); 107 } 108 109 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) 110 { 111 return timer->node.expires; 112 } 113 114 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) 115 { 116 return timer->_softexpires; 117 } 118 119 ktime_t hrtimer_cb_get_time(const struct hrtimer *timer); 120 121 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) 122 { 123 return ktime_sub(timer->node.expires, hrtimer_cb_get_time(timer)); 124 } 125 126 #ifdef CONFIG_HIGH_RES_TIMERS 127 extern unsigned int hrtimer_resolution; 128 struct clock_event_device; 129 130 extern void hrtimer_interrupt(struct clock_event_device *dev); 131 132 extern struct static_key_false hrtimer_highres_enabled_key; 133 134 static inline bool hrtimer_highres_enabled(void) 135 { 136 return static_branch_likely(&hrtimer_highres_enabled_key); 137 } 138 139 #else /* CONFIG_HIGH_RES_TIMERS */ 140 #define hrtimer_resolution (unsigned int)LOW_RES_NSEC 141 static inline bool hrtimer_highres_enabled(void) { return false; } 142 #endif /* !CONFIG_HIGH_RES_TIMERS */ 143 144 static inline ktime_t 145 __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now) 146 { 147 ktime_t rem = ktime_sub(timer->node.expires, now); 148 149 /* 150 * Adjust relative timers for the extra we added in 151 * hrtimer_start_range_ns() to prevent short timeouts. 152 */ 153 if (IS_ENABLED(CONFIG_TIME_LOW_RES) && timer->is_rel) 154 rem -= hrtimer_resolution; 155 return rem; 156 } 157 158 static inline ktime_t 159 hrtimer_expires_remaining_adjusted(const struct hrtimer *timer) 160 { 161 return __hrtimer_expires_remaining_adjusted(timer, hrtimer_cb_get_time(timer)); 162 } 163 164 #ifdef CONFIG_TIMERFD 165 extern void timerfd_clock_was_set(void); 166 extern void timerfd_resume(void); 167 #else 168 static inline void timerfd_clock_was_set(void) { } 169 static inline void timerfd_resume(void) { } 170 #endif 171 172 DECLARE_PER_CPU(struct tick_device, tick_cpu_device); 173 174 #ifdef CONFIG_PREEMPT_RT 175 void hrtimer_cancel_wait_running(const struct hrtimer *timer); 176 #else 177 static inline void hrtimer_cancel_wait_running(struct hrtimer *timer) 178 { 179 cpu_relax(); 180 } 181 #endif 182 183 static inline enum hrtimer_restart hrtimer_dummy_timeout(struct hrtimer *unused) 184 { 185 return HRTIMER_NORESTART; 186 } 187 188 /* Exported timer functions: */ 189 190 /* Initialize timers: */ 191 extern void hrtimer_setup(struct hrtimer *timer, enum hrtimer_restart (*function)(struct hrtimer *), 192 clockid_t clock_id, enum hrtimer_mode mode); 193 extern void hrtimer_setup_on_stack(struct hrtimer *timer, 194 enum hrtimer_restart (*function)(struct hrtimer *), 195 clockid_t clock_id, enum hrtimer_mode mode); 196 extern void hrtimer_setup_sleeper_on_stack(struct hrtimer_sleeper *sl, clockid_t clock_id, 197 enum hrtimer_mode mode); 198 199 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS 200 extern void destroy_hrtimer_on_stack(struct hrtimer *timer); 201 #else 202 static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } 203 #endif 204 205 /* Basic timer operations: */ 206 extern void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, 207 u64 range_ns, const enum hrtimer_mode mode); 208 209 /** 210 * hrtimer_start - (re)start an hrtimer 211 * @timer: the timer to be added 212 * @tim: expiry time 213 * @mode: timer mode: absolute (HRTIMER_MODE_ABS) or 214 * relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED); 215 * softirq based mode is considered for debug purpose only! 216 */ 217 static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim, 218 const enum hrtimer_mode mode) 219 { 220 hrtimer_start_range_ns(timer, tim, 0, mode); 221 } 222 223 extern int hrtimer_cancel(struct hrtimer *timer); 224 extern int hrtimer_try_to_cancel(struct hrtimer *timer); 225 226 static inline void hrtimer_start_expires(struct hrtimer *timer, 227 enum hrtimer_mode mode) 228 { 229 u64 delta; 230 ktime_t soft, hard; 231 soft = hrtimer_get_softexpires(timer); 232 hard = hrtimer_get_expires(timer); 233 delta = ktime_to_ns(ktime_sub(hard, soft)); 234 hrtimer_start_range_ns(timer, soft, delta, mode); 235 } 236 237 void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl, 238 enum hrtimer_mode mode); 239 240 static inline void hrtimer_restart(struct hrtimer *timer) 241 { 242 hrtimer_start_expires(timer, HRTIMER_MODE_ABS); 243 } 244 245 /* Query timers: */ 246 extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust); 247 248 /** 249 * hrtimer_get_remaining - get remaining time for the timer 250 * @timer: the timer to read 251 */ 252 static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) 253 { 254 return __hrtimer_get_remaining(timer, false); 255 } 256 257 extern u64 hrtimer_get_next_event(void); 258 extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); 259 260 extern bool hrtimer_active(const struct hrtimer *timer); 261 262 /** 263 * hrtimer_is_queued - check, whether the timer is on one of the queues 264 * @timer: Timer to check 265 * 266 * Returns: True if the timer is queued, false otherwise 267 * 268 * The function can be used lockless, but it gives only a current snapshot. 269 */ 270 static inline bool hrtimer_is_queued(struct hrtimer *timer) 271 { 272 /* The READ_ONCE pairs with the update functions of timer->is_queued */ 273 return READ_ONCE(timer->is_queued); 274 } 275 276 /* 277 * Helper function to check, whether the timer is running the callback 278 * function 279 */ 280 static inline int hrtimer_callback_running(struct hrtimer *timer) 281 { 282 return timer->base->running == timer; 283 } 284 285 /** 286 * hrtimer_update_function - Update the timer's callback function 287 * @timer: Timer to update 288 * @function: New callback function 289 * 290 * Only safe to call if the timer is not enqueued. Can be called in the callback function if the 291 * timer is not enqueued at the same time (see the comments above HRTIMER_STATE_ENQUEUED). 292 */ 293 static inline void hrtimer_update_function(struct hrtimer *timer, 294 enum hrtimer_restart (*function)(struct hrtimer *)) 295 { 296 #ifdef CONFIG_PROVE_LOCKING 297 guard(raw_spinlock_irqsave)(&timer->base->cpu_base->lock); 298 299 if (WARN_ON_ONCE(hrtimer_is_queued(timer))) 300 return; 301 302 if (WARN_ON_ONCE(!function)) 303 return; 304 #endif 305 ACCESS_PRIVATE(timer, function) = function; 306 } 307 308 /* Forward a hrtimer so it expires after now: */ 309 extern u64 310 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); 311 312 /** 313 * hrtimer_forward_now() - forward the timer expiry so it expires after now 314 * @timer: hrtimer to forward 315 * @interval: the interval to forward 316 * 317 * It is a variant of hrtimer_forward(). The timer will expire after the current 318 * time of the hrtimer clock base. See hrtimer_forward() for details. 319 */ 320 static inline u64 hrtimer_forward_now(struct hrtimer *timer, 321 ktime_t interval) 322 { 323 return hrtimer_forward(timer, hrtimer_cb_get_time(timer), interval); 324 } 325 326 /* Precise sleep: */ 327 328 extern int nanosleep_copyout(struct restart_block *, struct timespec64 *); 329 extern long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode, 330 const clockid_t clockid); 331 332 extern int schedule_hrtimeout_range(ktime_t *expires, u64 delta, 333 const enum hrtimer_mode mode); 334 extern int schedule_hrtimeout_range_clock(ktime_t *expires, 335 u64 delta, 336 const enum hrtimer_mode mode, 337 clockid_t clock_id); 338 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); 339 340 /* Soft interrupt function to run the hrtimer queues: */ 341 extern void hrtimer_run_queues(void); 342 343 /* Bootup initialization: */ 344 extern void __init hrtimers_init(void); 345 346 /* Show pending timers: */ 347 extern void sysrq_timer_list_show(void); 348 349 int hrtimers_prepare_cpu(unsigned int cpu); 350 int hrtimers_cpu_starting(unsigned int cpu); 351 #ifdef CONFIG_HOTPLUG_CPU 352 int hrtimers_cpu_dying(unsigned int cpu); 353 #else 354 #define hrtimers_cpu_dying NULL 355 #endif 356 357 #endif 358