Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/timer.c | |
3 | * | |
4 | * Kernel internal timers, kernel timekeeping, basic process system calls | |
5 | * | |
6 | * Copyright (C) 1991, 1992 Linus Torvalds | |
7 | * | |
8 | * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. | |
9 | * | |
10 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | |
11 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
12 | * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to | |
13 | * serialize accesses to xtime/lost_ticks). | |
14 | * Copyright (C) 1998 Andrea Arcangeli | |
15 | * 1999-03-10 Improved NTP compatibility by Ulrich Windl | |
16 | * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love | |
17 | * 2000-10-05 Implemented scalable SMP per-CPU timer handling. | |
18 | * Copyright (C) 2000, 2001, 2002 Ingo Molnar | |
19 | * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar | |
20 | */ | |
21 | ||
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/percpu.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/swap.h> | |
29 | #include <linux/notifier.h> | |
30 | #include <linux/thread_info.h> | |
31 | #include <linux/time.h> | |
32 | #include <linux/jiffies.h> | |
33 | #include <linux/posix-timers.h> | |
34 | #include <linux/cpu.h> | |
35 | #include <linux/syscalls.h> | |
36 | ||
37 | #include <asm/uaccess.h> | |
38 | #include <asm/unistd.h> | |
39 | #include <asm/div64.h> | |
40 | #include <asm/timex.h> | |
41 | #include <asm/io.h> | |
42 | ||
43 | #ifdef CONFIG_TIME_INTERPOLATION | |
44 | static void time_interpolator_update(long delta_nsec); | |
45 | #else | |
46 | #define time_interpolator_update(x) | |
47 | #endif | |
48 | ||
ecea8d19 TG |
49 | u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; |
50 | ||
51 | EXPORT_SYMBOL(jiffies_64); | |
52 | ||
1da177e4 LT |
53 | /* |
54 | * per-CPU timer vector definitions: | |
55 | */ | |
56 | ||
57 | #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) | |
58 | #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) | |
59 | #define TVN_SIZE (1 << TVN_BITS) | |
60 | #define TVR_SIZE (1 << TVR_BITS) | |
61 | #define TVN_MASK (TVN_SIZE - 1) | |
62 | #define TVR_MASK (TVR_SIZE - 1) | |
63 | ||
55c888d6 ON |
64 | struct timer_base_s { |
65 | spinlock_t lock; | |
66 | struct timer_list *running_timer; | |
67 | }; | |
68 | ||
1da177e4 LT |
69 | typedef struct tvec_s { |
70 | struct list_head vec[TVN_SIZE]; | |
71 | } tvec_t; | |
72 | ||
73 | typedef struct tvec_root_s { | |
74 | struct list_head vec[TVR_SIZE]; | |
75 | } tvec_root_t; | |
76 | ||
77 | struct tvec_t_base_s { | |
55c888d6 | 78 | struct timer_base_s t_base; |
1da177e4 | 79 | unsigned long timer_jiffies; |
1da177e4 LT |
80 | tvec_root_t tv1; |
81 | tvec_t tv2; | |
82 | tvec_t tv3; | |
83 | tvec_t tv4; | |
84 | tvec_t tv5; | |
85 | } ____cacheline_aligned_in_smp; | |
86 | ||
87 | typedef struct tvec_t_base_s tvec_base_t; | |
55c888d6 | 88 | static DEFINE_PER_CPU(tvec_base_t, tvec_bases); |
1da177e4 LT |
89 | |
90 | static inline void set_running_timer(tvec_base_t *base, | |
91 | struct timer_list *timer) | |
92 | { | |
93 | #ifdef CONFIG_SMP | |
55c888d6 | 94 | base->t_base.running_timer = timer; |
1da177e4 LT |
95 | #endif |
96 | } | |
97 | ||
1da177e4 LT |
98 | static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) |
99 | { | |
100 | unsigned long expires = timer->expires; | |
101 | unsigned long idx = expires - base->timer_jiffies; | |
102 | struct list_head *vec; | |
103 | ||
104 | if (idx < TVR_SIZE) { | |
105 | int i = expires & TVR_MASK; | |
106 | vec = base->tv1.vec + i; | |
107 | } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { | |
108 | int i = (expires >> TVR_BITS) & TVN_MASK; | |
109 | vec = base->tv2.vec + i; | |
110 | } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { | |
111 | int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; | |
112 | vec = base->tv3.vec + i; | |
113 | } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { | |
114 | int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; | |
115 | vec = base->tv4.vec + i; | |
116 | } else if ((signed long) idx < 0) { | |
117 | /* | |
118 | * Can happen if you add a timer with expires == jiffies, | |
119 | * or you set a timer to go off in the past | |
120 | */ | |
121 | vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); | |
122 | } else { | |
123 | int i; | |
124 | /* If the timeout is larger than 0xffffffff on 64-bit | |
125 | * architectures then we use the maximum timeout: | |
126 | */ | |
127 | if (idx > 0xffffffffUL) { | |
128 | idx = 0xffffffffUL; | |
129 | expires = idx + base->timer_jiffies; | |
130 | } | |
131 | i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; | |
132 | vec = base->tv5.vec + i; | |
133 | } | |
134 | /* | |
135 | * Timers are FIFO: | |
136 | */ | |
137 | list_add_tail(&timer->entry, vec); | |
138 | } | |
139 | ||
55c888d6 ON |
140 | typedef struct timer_base_s timer_base_t; |
141 | /* | |
142 | * Used by TIMER_INITIALIZER, we can't use per_cpu(tvec_bases) | |
143 | * at compile time, and we need timer->base to lock the timer. | |
144 | */ | |
145 | timer_base_t __init_timer_base | |
146 | ____cacheline_aligned_in_smp = { .lock = SPIN_LOCK_UNLOCKED }; | |
147 | EXPORT_SYMBOL(__init_timer_base); | |
148 | ||
149 | /*** | |
150 | * init_timer - initialize a timer. | |
151 | * @timer: the timer to be initialized | |
152 | * | |
153 | * init_timer() must be done to a timer prior calling *any* of the | |
154 | * other timer functions. | |
155 | */ | |
156 | void fastcall init_timer(struct timer_list *timer) | |
157 | { | |
158 | timer->entry.next = NULL; | |
159 | timer->base = &per_cpu(tvec_bases, raw_smp_processor_id()).t_base; | |
55c888d6 ON |
160 | } |
161 | EXPORT_SYMBOL(init_timer); | |
162 | ||
163 | static inline void detach_timer(struct timer_list *timer, | |
164 | int clear_pending) | |
165 | { | |
166 | struct list_head *entry = &timer->entry; | |
167 | ||
168 | __list_del(entry->prev, entry->next); | |
169 | if (clear_pending) | |
170 | entry->next = NULL; | |
171 | entry->prev = LIST_POISON2; | |
172 | } | |
173 | ||
174 | /* | |
175 | * We are using hashed locking: holding per_cpu(tvec_bases).t_base.lock | |
176 | * means that all timers which are tied to this base via timer->base are | |
177 | * locked, and the base itself is locked too. | |
178 | * | |
179 | * So __run_timers/migrate_timers can safely modify all timers which could | |
180 | * be found on ->tvX lists. | |
181 | * | |
182 | * When the timer's base is locked, and the timer removed from list, it is | |
183 | * possible to set timer->base = NULL and drop the lock: the timer remains | |
184 | * locked. | |
185 | */ | |
186 | static timer_base_t *lock_timer_base(struct timer_list *timer, | |
187 | unsigned long *flags) | |
188 | { | |
189 | timer_base_t *base; | |
190 | ||
191 | for (;;) { | |
192 | base = timer->base; | |
193 | if (likely(base != NULL)) { | |
194 | spin_lock_irqsave(&base->lock, *flags); | |
195 | if (likely(base == timer->base)) | |
196 | return base; | |
197 | /* The timer has migrated to another CPU */ | |
198 | spin_unlock_irqrestore(&base->lock, *flags); | |
199 | } | |
200 | cpu_relax(); | |
201 | } | |
202 | } | |
203 | ||
1da177e4 LT |
204 | int __mod_timer(struct timer_list *timer, unsigned long expires) |
205 | { | |
55c888d6 ON |
206 | timer_base_t *base; |
207 | tvec_base_t *new_base; | |
1da177e4 LT |
208 | unsigned long flags; |
209 | int ret = 0; | |
210 | ||
211 | BUG_ON(!timer->function); | |
1da177e4 | 212 | |
55c888d6 ON |
213 | base = lock_timer_base(timer, &flags); |
214 | ||
215 | if (timer_pending(timer)) { | |
216 | detach_timer(timer, 0); | |
217 | ret = 1; | |
218 | } | |
219 | ||
1da177e4 | 220 | new_base = &__get_cpu_var(tvec_bases); |
1da177e4 | 221 | |
55c888d6 | 222 | if (base != &new_base->t_base) { |
1da177e4 | 223 | /* |
55c888d6 ON |
224 | * We are trying to schedule the timer on the local CPU. |
225 | * However we can't change timer's base while it is running, | |
226 | * otherwise del_timer_sync() can't detect that the timer's | |
227 | * handler yet has not finished. This also guarantees that | |
228 | * the timer is serialized wrt itself. | |
1da177e4 | 229 | */ |
55c888d6 ON |
230 | if (unlikely(base->running_timer == timer)) { |
231 | /* The timer remains on a former base */ | |
232 | new_base = container_of(base, tvec_base_t, t_base); | |
233 | } else { | |
234 | /* See the comment in lock_timer_base() */ | |
235 | timer->base = NULL; | |
236 | spin_unlock(&base->lock); | |
237 | spin_lock(&new_base->t_base.lock); | |
238 | timer->base = &new_base->t_base; | |
1da177e4 LT |
239 | } |
240 | } | |
241 | ||
1da177e4 LT |
242 | timer->expires = expires; |
243 | internal_add_timer(new_base, timer); | |
55c888d6 | 244 | spin_unlock_irqrestore(&new_base->t_base.lock, flags); |
1da177e4 LT |
245 | |
246 | return ret; | |
247 | } | |
248 | ||
249 | EXPORT_SYMBOL(__mod_timer); | |
250 | ||
251 | /*** | |
252 | * add_timer_on - start a timer on a particular CPU | |
253 | * @timer: the timer to be added | |
254 | * @cpu: the CPU to start it on | |
255 | * | |
256 | * This is not very scalable on SMP. Double adds are not possible. | |
257 | */ | |
258 | void add_timer_on(struct timer_list *timer, int cpu) | |
259 | { | |
260 | tvec_base_t *base = &per_cpu(tvec_bases, cpu); | |
261 | unsigned long flags; | |
55c888d6 | 262 | |
1da177e4 | 263 | BUG_ON(timer_pending(timer) || !timer->function); |
55c888d6 ON |
264 | spin_lock_irqsave(&base->t_base.lock, flags); |
265 | timer->base = &base->t_base; | |
1da177e4 | 266 | internal_add_timer(base, timer); |
55c888d6 | 267 | spin_unlock_irqrestore(&base->t_base.lock, flags); |
1da177e4 LT |
268 | } |
269 | ||
270 | ||
271 | /*** | |
272 | * mod_timer - modify a timer's timeout | |
273 | * @timer: the timer to be modified | |
274 | * | |
275 | * mod_timer is a more efficient way to update the expire field of an | |
276 | * active timer (if the timer is inactive it will be activated) | |
277 | * | |
278 | * mod_timer(timer, expires) is equivalent to: | |
279 | * | |
280 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
281 | * | |
282 | * Note that if there are multiple unserialized concurrent users of the | |
283 | * same timer, then mod_timer() is the only safe way to modify the timeout, | |
284 | * since add_timer() cannot modify an already running timer. | |
285 | * | |
286 | * The function returns whether it has modified a pending timer or not. | |
287 | * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an | |
288 | * active timer returns 1.) | |
289 | */ | |
290 | int mod_timer(struct timer_list *timer, unsigned long expires) | |
291 | { | |
292 | BUG_ON(!timer->function); | |
293 | ||
1da177e4 LT |
294 | /* |
295 | * This is a common optimization triggered by the | |
296 | * networking code - if the timer is re-modified | |
297 | * to be the same thing then just return: | |
298 | */ | |
299 | if (timer->expires == expires && timer_pending(timer)) | |
300 | return 1; | |
301 | ||
302 | return __mod_timer(timer, expires); | |
303 | } | |
304 | ||
305 | EXPORT_SYMBOL(mod_timer); | |
306 | ||
307 | /*** | |
308 | * del_timer - deactive a timer. | |
309 | * @timer: the timer to be deactivated | |
310 | * | |
311 | * del_timer() deactivates a timer - this works on both active and inactive | |
312 | * timers. | |
313 | * | |
314 | * The function returns whether it has deactivated a pending timer or not. | |
315 | * (ie. del_timer() of an inactive timer returns 0, del_timer() of an | |
316 | * active timer returns 1.) | |
317 | */ | |
318 | int del_timer(struct timer_list *timer) | |
319 | { | |
55c888d6 | 320 | timer_base_t *base; |
1da177e4 | 321 | unsigned long flags; |
55c888d6 | 322 | int ret = 0; |
1da177e4 | 323 | |
55c888d6 ON |
324 | if (timer_pending(timer)) { |
325 | base = lock_timer_base(timer, &flags); | |
326 | if (timer_pending(timer)) { | |
327 | detach_timer(timer, 1); | |
328 | ret = 1; | |
329 | } | |
1da177e4 | 330 | spin_unlock_irqrestore(&base->lock, flags); |
1da177e4 | 331 | } |
1da177e4 | 332 | |
55c888d6 | 333 | return ret; |
1da177e4 LT |
334 | } |
335 | ||
336 | EXPORT_SYMBOL(del_timer); | |
337 | ||
338 | #ifdef CONFIG_SMP | |
fd450b73 ON |
339 | /* |
340 | * This function tries to deactivate a timer. Upon successful (ret >= 0) | |
341 | * exit the timer is not queued and the handler is not running on any CPU. | |
342 | * | |
343 | * It must not be called from interrupt contexts. | |
344 | */ | |
345 | int try_to_del_timer_sync(struct timer_list *timer) | |
346 | { | |
347 | timer_base_t *base; | |
348 | unsigned long flags; | |
349 | int ret = -1; | |
350 | ||
351 | base = lock_timer_base(timer, &flags); | |
352 | ||
353 | if (base->running_timer == timer) | |
354 | goto out; | |
355 | ||
356 | ret = 0; | |
357 | if (timer_pending(timer)) { | |
358 | detach_timer(timer, 1); | |
359 | ret = 1; | |
360 | } | |
361 | out: | |
362 | spin_unlock_irqrestore(&base->lock, flags); | |
363 | ||
364 | return ret; | |
365 | } | |
366 | ||
1da177e4 LT |
367 | /*** |
368 | * del_timer_sync - deactivate a timer and wait for the handler to finish. | |
369 | * @timer: the timer to be deactivated | |
370 | * | |
371 | * This function only differs from del_timer() on SMP: besides deactivating | |
372 | * the timer it also makes sure the handler has finished executing on other | |
373 | * CPUs. | |
374 | * | |
375 | * Synchronization rules: callers must prevent restarting of the timer, | |
376 | * otherwise this function is meaningless. It must not be called from | |
377 | * interrupt contexts. The caller must not hold locks which would prevent | |
55c888d6 ON |
378 | * completion of the timer's handler. The timer's handler must not call |
379 | * add_timer_on(). Upon exit the timer is not queued and the handler is | |
380 | * not running on any CPU. | |
1da177e4 LT |
381 | * |
382 | * The function returns whether it has deactivated a pending timer or not. | |
1da177e4 LT |
383 | */ |
384 | int del_timer_sync(struct timer_list *timer) | |
385 | { | |
fd450b73 ON |
386 | for (;;) { |
387 | int ret = try_to_del_timer_sync(timer); | |
388 | if (ret >= 0) | |
389 | return ret; | |
390 | } | |
1da177e4 | 391 | } |
1da177e4 | 392 | |
55c888d6 | 393 | EXPORT_SYMBOL(del_timer_sync); |
1da177e4 LT |
394 | #endif |
395 | ||
396 | static int cascade(tvec_base_t *base, tvec_t *tv, int index) | |
397 | { | |
398 | /* cascade all the timers from tv up one level */ | |
399 | struct list_head *head, *curr; | |
400 | ||
401 | head = tv->vec + index; | |
402 | curr = head->next; | |
403 | /* | |
404 | * We are removing _all_ timers from the list, so we don't have to | |
405 | * detach them individually, just clear the list afterwards. | |
406 | */ | |
407 | while (curr != head) { | |
408 | struct timer_list *tmp; | |
409 | ||
410 | tmp = list_entry(curr, struct timer_list, entry); | |
55c888d6 | 411 | BUG_ON(tmp->base != &base->t_base); |
1da177e4 LT |
412 | curr = curr->next; |
413 | internal_add_timer(base, tmp); | |
414 | } | |
415 | INIT_LIST_HEAD(head); | |
416 | ||
417 | return index; | |
418 | } | |
419 | ||
420 | /*** | |
421 | * __run_timers - run all expired timers (if any) on this CPU. | |
422 | * @base: the timer vector to be processed. | |
423 | * | |
424 | * This function cascades all vectors and executes all expired timer | |
425 | * vectors. | |
426 | */ | |
427 | #define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK | |
428 | ||
429 | static inline void __run_timers(tvec_base_t *base) | |
430 | { | |
431 | struct timer_list *timer; | |
432 | ||
55c888d6 | 433 | spin_lock_irq(&base->t_base.lock); |
1da177e4 LT |
434 | while (time_after_eq(jiffies, base->timer_jiffies)) { |
435 | struct list_head work_list = LIST_HEAD_INIT(work_list); | |
436 | struct list_head *head = &work_list; | |
437 | int index = base->timer_jiffies & TVR_MASK; | |
438 | ||
439 | /* | |
440 | * Cascade timers: | |
441 | */ | |
442 | if (!index && | |
443 | (!cascade(base, &base->tv2, INDEX(0))) && | |
444 | (!cascade(base, &base->tv3, INDEX(1))) && | |
445 | !cascade(base, &base->tv4, INDEX(2))) | |
446 | cascade(base, &base->tv5, INDEX(3)); | |
447 | ++base->timer_jiffies; | |
448 | list_splice_init(base->tv1.vec + index, &work_list); | |
55c888d6 | 449 | while (!list_empty(head)) { |
1da177e4 LT |
450 | void (*fn)(unsigned long); |
451 | unsigned long data; | |
452 | ||
453 | timer = list_entry(head->next,struct timer_list,entry); | |
454 | fn = timer->function; | |
455 | data = timer->data; | |
456 | ||
1da177e4 | 457 | set_running_timer(base, timer); |
55c888d6 ON |
458 | detach_timer(timer, 1); |
459 | spin_unlock_irq(&base->t_base.lock); | |
1da177e4 | 460 | { |
be5b4fbd | 461 | int preempt_count = preempt_count(); |
1da177e4 LT |
462 | fn(data); |
463 | if (preempt_count != preempt_count()) { | |
be5b4fbd JJ |
464 | printk(KERN_WARNING "huh, entered %p " |
465 | "with preempt_count %08x, exited" | |
466 | " with %08x?\n", | |
467 | fn, preempt_count, | |
468 | preempt_count()); | |
1da177e4 LT |
469 | BUG(); |
470 | } | |
471 | } | |
55c888d6 | 472 | spin_lock_irq(&base->t_base.lock); |
1da177e4 LT |
473 | } |
474 | } | |
475 | set_running_timer(base, NULL); | |
55c888d6 | 476 | spin_unlock_irq(&base->t_base.lock); |
1da177e4 LT |
477 | } |
478 | ||
479 | #ifdef CONFIG_NO_IDLE_HZ | |
480 | /* | |
481 | * Find out when the next timer event is due to happen. This | |
482 | * is used on S/390 to stop all activity when a cpus is idle. | |
483 | * This functions needs to be called disabled. | |
484 | */ | |
485 | unsigned long next_timer_interrupt(void) | |
486 | { | |
487 | tvec_base_t *base; | |
488 | struct list_head *list; | |
489 | struct timer_list *nte; | |
490 | unsigned long expires; | |
491 | tvec_t *varray[4]; | |
492 | int i, j; | |
493 | ||
494 | base = &__get_cpu_var(tvec_bases); | |
55c888d6 | 495 | spin_lock(&base->t_base.lock); |
1da177e4 LT |
496 | expires = base->timer_jiffies + (LONG_MAX >> 1); |
497 | list = 0; | |
498 | ||
499 | /* Look for timer events in tv1. */ | |
500 | j = base->timer_jiffies & TVR_MASK; | |
501 | do { | |
502 | list_for_each_entry(nte, base->tv1.vec + j, entry) { | |
503 | expires = nte->expires; | |
504 | if (j < (base->timer_jiffies & TVR_MASK)) | |
505 | list = base->tv2.vec + (INDEX(0)); | |
506 | goto found; | |
507 | } | |
508 | j = (j + 1) & TVR_MASK; | |
509 | } while (j != (base->timer_jiffies & TVR_MASK)); | |
510 | ||
511 | /* Check tv2-tv5. */ | |
512 | varray[0] = &base->tv2; | |
513 | varray[1] = &base->tv3; | |
514 | varray[2] = &base->tv4; | |
515 | varray[3] = &base->tv5; | |
516 | for (i = 0; i < 4; i++) { | |
517 | j = INDEX(i); | |
518 | do { | |
519 | if (list_empty(varray[i]->vec + j)) { | |
520 | j = (j + 1) & TVN_MASK; | |
521 | continue; | |
522 | } | |
523 | list_for_each_entry(nte, varray[i]->vec + j, entry) | |
524 | if (time_before(nte->expires, expires)) | |
525 | expires = nte->expires; | |
526 | if (j < (INDEX(i)) && i < 3) | |
527 | list = varray[i + 1]->vec + (INDEX(i + 1)); | |
528 | goto found; | |
529 | } while (j != (INDEX(i))); | |
530 | } | |
531 | found: | |
532 | if (list) { | |
533 | /* | |
534 | * The search wrapped. We need to look at the next list | |
535 | * from next tv element that would cascade into tv element | |
536 | * where we found the timer element. | |
537 | */ | |
538 | list_for_each_entry(nte, list, entry) { | |
539 | if (time_before(nte->expires, expires)) | |
540 | expires = nte->expires; | |
541 | } | |
542 | } | |
55c888d6 | 543 | spin_unlock(&base->t_base.lock); |
1da177e4 LT |
544 | return expires; |
545 | } | |
546 | #endif | |
547 | ||
548 | /******************************************************************/ | |
549 | ||
550 | /* | |
551 | * Timekeeping variables | |
552 | */ | |
553 | unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */ | |
554 | unsigned long tick_nsec = TICK_NSEC; /* ACTHZ period (nsec) */ | |
555 | ||
556 | /* | |
557 | * The current time | |
558 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
559 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
560 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
561 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
562 | * the usual normalization. | |
563 | */ | |
564 | struct timespec xtime __attribute__ ((aligned (16))); | |
565 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); | |
566 | ||
567 | EXPORT_SYMBOL(xtime); | |
568 | ||
569 | /* Don't completely fail for HZ > 500. */ | |
570 | int tickadj = 500/HZ ? : 1; /* microsecs */ | |
571 | ||
572 | ||
573 | /* | |
574 | * phase-lock loop variables | |
575 | */ | |
576 | /* TIME_ERROR prevents overwriting the CMOS clock */ | |
577 | int time_state = TIME_OK; /* clock synchronization status */ | |
578 | int time_status = STA_UNSYNC; /* clock status bits */ | |
579 | long time_offset; /* time adjustment (us) */ | |
580 | long time_constant = 2; /* pll time constant */ | |
581 | long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */ | |
582 | long time_precision = 1; /* clock precision (us) */ | |
583 | long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ | |
584 | long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ | |
585 | static long time_phase; /* phase offset (scaled us) */ | |
586 | long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC; | |
587 | /* frequency offset (scaled ppm)*/ | |
588 | static long time_adj; /* tick adjust (scaled 1 / HZ) */ | |
589 | long time_reftime; /* time at last adjustment (s) */ | |
590 | long time_adjust; | |
591 | long time_next_adjust; | |
592 | ||
593 | /* | |
594 | * this routine handles the overflow of the microsecond field | |
595 | * | |
596 | * The tricky bits of code to handle the accurate clock support | |
597 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. | |
598 | * They were originally developed for SUN and DEC kernels. | |
599 | * All the kudos should go to Dave for this stuff. | |
600 | * | |
601 | */ | |
602 | static void second_overflow(void) | |
603 | { | |
a5a0d52c AM |
604 | long ltemp; |
605 | ||
606 | /* Bump the maxerror field */ | |
607 | time_maxerror += time_tolerance >> SHIFT_USEC; | |
608 | if (time_maxerror > NTP_PHASE_LIMIT) { | |
609 | time_maxerror = NTP_PHASE_LIMIT; | |
610 | time_status |= STA_UNSYNC; | |
1da177e4 | 611 | } |
a5a0d52c AM |
612 | |
613 | /* | |
614 | * Leap second processing. If in leap-insert state at the end of the | |
615 | * day, the system clock is set back one second; if in leap-delete | |
616 | * state, the system clock is set ahead one second. The microtime() | |
617 | * routine or external clock driver will insure that reported time is | |
618 | * always monotonic. The ugly divides should be replaced. | |
619 | */ | |
620 | switch (time_state) { | |
621 | case TIME_OK: | |
622 | if (time_status & STA_INS) | |
623 | time_state = TIME_INS; | |
624 | else if (time_status & STA_DEL) | |
625 | time_state = TIME_DEL; | |
626 | break; | |
627 | case TIME_INS: | |
628 | if (xtime.tv_sec % 86400 == 0) { | |
629 | xtime.tv_sec--; | |
630 | wall_to_monotonic.tv_sec++; | |
631 | /* | |
632 | * The timer interpolator will make time change | |
633 | * gradually instead of an immediate jump by one second | |
634 | */ | |
635 | time_interpolator_update(-NSEC_PER_SEC); | |
636 | time_state = TIME_OOP; | |
637 | clock_was_set(); | |
638 | printk(KERN_NOTICE "Clock: inserting leap second " | |
639 | "23:59:60 UTC\n"); | |
640 | } | |
641 | break; | |
642 | case TIME_DEL: | |
643 | if ((xtime.tv_sec + 1) % 86400 == 0) { | |
644 | xtime.tv_sec++; | |
645 | wall_to_monotonic.tv_sec--; | |
646 | /* | |
647 | * Use of time interpolator for a gradual change of | |
648 | * time | |
649 | */ | |
650 | time_interpolator_update(NSEC_PER_SEC); | |
651 | time_state = TIME_WAIT; | |
652 | clock_was_set(); | |
653 | printk(KERN_NOTICE "Clock: deleting leap second " | |
654 | "23:59:59 UTC\n"); | |
655 | } | |
656 | break; | |
657 | case TIME_OOP: | |
658 | time_state = TIME_WAIT; | |
659 | break; | |
660 | case TIME_WAIT: | |
661 | if (!(time_status & (STA_INS | STA_DEL))) | |
662 | time_state = TIME_OK; | |
1da177e4 | 663 | } |
a5a0d52c AM |
664 | |
665 | /* | |
666 | * Compute the phase adjustment for the next second. In PLL mode, the | |
667 | * offset is reduced by a fixed factor times the time constant. In FLL | |
668 | * mode the offset is used directly. In either mode, the maximum phase | |
669 | * adjustment for each second is clamped so as to spread the adjustment | |
670 | * over not more than the number of seconds between updates. | |
671 | */ | |
1da177e4 LT |
672 | ltemp = time_offset; |
673 | if (!(time_status & STA_FLL)) | |
1bb34a41 | 674 | ltemp = shift_right(ltemp, SHIFT_KG + time_constant); |
675 | ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE); | |
676 | ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE); | |
1da177e4 LT |
677 | time_offset -= ltemp; |
678 | time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); | |
1da177e4 | 679 | |
a5a0d52c AM |
680 | /* |
681 | * Compute the frequency estimate and additional phase adjustment due | |
682 | * to frequency error for the next second. When the PPS signal is | |
683 | * engaged, gnaw on the watchdog counter and update the frequency | |
684 | * computed by the pll and the PPS signal. | |
685 | */ | |
686 | pps_valid++; | |
687 | if (pps_valid == PPS_VALID) { /* PPS signal lost */ | |
688 | pps_jitter = MAXTIME; | |
689 | pps_stabil = MAXFREQ; | |
690 | time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | | |
691 | STA_PPSWANDER | STA_PPSERROR); | |
692 | } | |
693 | ltemp = time_freq + pps_freq; | |
694 | time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE)); | |
1da177e4 LT |
695 | |
696 | #if HZ == 100 | |
a5a0d52c AM |
697 | /* |
698 | * Compensate for (HZ==100) != (1 << SHIFT_HZ). Add 25% and 3.125% to | |
699 | * get 128.125; => only 0.125% error (p. 14) | |
700 | */ | |
701 | time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5); | |
1da177e4 | 702 | #endif |
4b8f573b | 703 | #if HZ == 250 |
a5a0d52c AM |
704 | /* |
705 | * Compensate for (HZ==250) != (1 << SHIFT_HZ). Add 1.5625% and | |
706 | * 0.78125% to get 255.85938; => only 0.05% error (p. 14) | |
707 | */ | |
708 | time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7); | |
4b8f573b | 709 | #endif |
1da177e4 | 710 | #if HZ == 1000 |
a5a0d52c AM |
711 | /* |
712 | * Compensate for (HZ==1000) != (1 << SHIFT_HZ). Add 1.5625% and | |
713 | * 0.78125% to get 1023.4375; => only 0.05% error (p. 14) | |
714 | */ | |
715 | time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7); | |
1da177e4 LT |
716 | #endif |
717 | } | |
718 | ||
719 | /* in the NTP reference this is called "hardclock()" */ | |
720 | static void update_wall_time_one_tick(void) | |
721 | { | |
722 | long time_adjust_step, delta_nsec; | |
723 | ||
a5a0d52c AM |
724 | if ((time_adjust_step = time_adjust) != 0 ) { |
725 | /* | |
726 | * We are doing an adjtime thing. Prepare time_adjust_step to | |
727 | * be within bounds. Note that a positive time_adjust means we | |
728 | * want the clock to run faster. | |
729 | * | |
730 | * Limit the amount of the step to be in the range | |
731 | * -tickadj .. +tickadj | |
732 | */ | |
733 | time_adjust_step = min(time_adjust_step, (long)tickadj); | |
734 | time_adjust_step = max(time_adjust_step, (long)-tickadj); | |
735 | ||
736 | /* Reduce by this step the amount of time left */ | |
737 | time_adjust -= time_adjust_step; | |
1da177e4 LT |
738 | } |
739 | delta_nsec = tick_nsec + time_adjust_step * 1000; | |
740 | /* | |
741 | * Advance the phase, once it gets to one microsecond, then | |
742 | * advance the tick more. | |
743 | */ | |
744 | time_phase += time_adj; | |
1bb34a41 | 745 | if ((time_phase >= FINENSEC) || (time_phase <= -FINENSEC)) { |
746 | long ltemp = shift_right(time_phase, (SHIFT_SCALE - 10)); | |
1da177e4 LT |
747 | time_phase -= ltemp << (SHIFT_SCALE - 10); |
748 | delta_nsec += ltemp; | |
749 | } | |
750 | xtime.tv_nsec += delta_nsec; | |
751 | time_interpolator_update(delta_nsec); | |
752 | ||
753 | /* Changes by adjtime() do not take effect till next tick. */ | |
754 | if (time_next_adjust != 0) { | |
755 | time_adjust = time_next_adjust; | |
756 | time_next_adjust = 0; | |
757 | } | |
758 | } | |
759 | ||
760 | /* | |
761 | * Using a loop looks inefficient, but "ticks" is | |
762 | * usually just one (we shouldn't be losing ticks, | |
763 | * we're doing this this way mainly for interrupt | |
764 | * latency reasons, not because we think we'll | |
765 | * have lots of lost timer ticks | |
766 | */ | |
767 | static void update_wall_time(unsigned long ticks) | |
768 | { | |
769 | do { | |
770 | ticks--; | |
771 | update_wall_time_one_tick(); | |
772 | if (xtime.tv_nsec >= 1000000000) { | |
773 | xtime.tv_nsec -= 1000000000; | |
774 | xtime.tv_sec++; | |
775 | second_overflow(); | |
776 | } | |
777 | } while (ticks); | |
778 | } | |
779 | ||
780 | /* | |
781 | * Called from the timer interrupt handler to charge one tick to the current | |
782 | * process. user_tick is 1 if the tick is user time, 0 for system. | |
783 | */ | |
784 | void update_process_times(int user_tick) | |
785 | { | |
786 | struct task_struct *p = current; | |
787 | int cpu = smp_processor_id(); | |
788 | ||
789 | /* Note: this timer irq context must be accounted for as well. */ | |
790 | if (user_tick) | |
791 | account_user_time(p, jiffies_to_cputime(1)); | |
792 | else | |
793 | account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1)); | |
794 | run_local_timers(); | |
795 | if (rcu_pending(cpu)) | |
796 | rcu_check_callbacks(cpu, user_tick); | |
797 | scheduler_tick(); | |
798 | run_posix_cpu_timers(p); | |
799 | } | |
800 | ||
801 | /* | |
802 | * Nr of active tasks - counted in fixed-point numbers | |
803 | */ | |
804 | static unsigned long count_active_tasks(void) | |
805 | { | |
806 | return (nr_running() + nr_uninterruptible()) * FIXED_1; | |
807 | } | |
808 | ||
809 | /* | |
810 | * Hmm.. Changed this, as the GNU make sources (load.c) seems to | |
811 | * imply that avenrun[] is the standard name for this kind of thing. | |
812 | * Nothing else seems to be standardized: the fractional size etc | |
813 | * all seem to differ on different machines. | |
814 | * | |
815 | * Requires xtime_lock to access. | |
816 | */ | |
817 | unsigned long avenrun[3]; | |
818 | ||
819 | EXPORT_SYMBOL(avenrun); | |
820 | ||
821 | /* | |
822 | * calc_load - given tick count, update the avenrun load estimates. | |
823 | * This is called while holding a write_lock on xtime_lock. | |
824 | */ | |
825 | static inline void calc_load(unsigned long ticks) | |
826 | { | |
827 | unsigned long active_tasks; /* fixed-point */ | |
828 | static int count = LOAD_FREQ; | |
829 | ||
830 | count -= ticks; | |
831 | if (count < 0) { | |
832 | count += LOAD_FREQ; | |
833 | active_tasks = count_active_tasks(); | |
834 | CALC_LOAD(avenrun[0], EXP_1, active_tasks); | |
835 | CALC_LOAD(avenrun[1], EXP_5, active_tasks); | |
836 | CALC_LOAD(avenrun[2], EXP_15, active_tasks); | |
837 | } | |
838 | } | |
839 | ||
840 | /* jiffies at the most recent update of wall time */ | |
841 | unsigned long wall_jiffies = INITIAL_JIFFIES; | |
842 | ||
843 | /* | |
844 | * This read-write spinlock protects us from races in SMP while | |
845 | * playing with xtime and avenrun. | |
846 | */ | |
847 | #ifndef ARCH_HAVE_XTIME_LOCK | |
848 | seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; | |
849 | ||
850 | EXPORT_SYMBOL(xtime_lock); | |
851 | #endif | |
852 | ||
853 | /* | |
854 | * This function runs timers and the timer-tq in bottom half context. | |
855 | */ | |
856 | static void run_timer_softirq(struct softirq_action *h) | |
857 | { | |
858 | tvec_base_t *base = &__get_cpu_var(tvec_bases); | |
859 | ||
860 | if (time_after_eq(jiffies, base->timer_jiffies)) | |
861 | __run_timers(base); | |
862 | } | |
863 | ||
864 | /* | |
865 | * Called by the local, per-CPU timer interrupt on SMP. | |
866 | */ | |
867 | void run_local_timers(void) | |
868 | { | |
869 | raise_softirq(TIMER_SOFTIRQ); | |
870 | } | |
871 | ||
872 | /* | |
873 | * Called by the timer interrupt. xtime_lock must already be taken | |
874 | * by the timer IRQ! | |
875 | */ | |
876 | static inline void update_times(void) | |
877 | { | |
878 | unsigned long ticks; | |
879 | ||
880 | ticks = jiffies - wall_jiffies; | |
881 | if (ticks) { | |
882 | wall_jiffies += ticks; | |
883 | update_wall_time(ticks); | |
884 | } | |
885 | calc_load(ticks); | |
886 | } | |
887 | ||
888 | /* | |
889 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
890 | * without sampling the sequence number in xtime_lock. | |
891 | * jiffies is defined in the linker script... | |
892 | */ | |
893 | ||
894 | void do_timer(struct pt_regs *regs) | |
895 | { | |
896 | jiffies_64++; | |
897 | update_times(); | |
8446f1d3 | 898 | softlockup_tick(regs); |
1da177e4 LT |
899 | } |
900 | ||
901 | #ifdef __ARCH_WANT_SYS_ALARM | |
902 | ||
903 | /* | |
904 | * For backwards compatibility? This can be done in libc so Alpha | |
905 | * and all newer ports shouldn't need it. | |
906 | */ | |
907 | asmlinkage unsigned long sys_alarm(unsigned int seconds) | |
908 | { | |
909 | struct itimerval it_new, it_old; | |
910 | unsigned int oldalarm; | |
911 | ||
912 | it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; | |
913 | it_new.it_value.tv_sec = seconds; | |
914 | it_new.it_value.tv_usec = 0; | |
915 | do_setitimer(ITIMER_REAL, &it_new, &it_old); | |
916 | oldalarm = it_old.it_value.tv_sec; | |
917 | /* ehhh.. We can't return 0 if we have an alarm pending.. */ | |
918 | /* And we'd better return too much than too little anyway */ | |
919 | if ((!oldalarm && it_old.it_value.tv_usec) || it_old.it_value.tv_usec >= 500000) | |
920 | oldalarm++; | |
921 | return oldalarm; | |
922 | } | |
923 | ||
924 | #endif | |
925 | ||
926 | #ifndef __alpha__ | |
927 | ||
928 | /* | |
929 | * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this | |
930 | * should be moved into arch/i386 instead? | |
931 | */ | |
932 | ||
933 | /** | |
934 | * sys_getpid - return the thread group id of the current process | |
935 | * | |
936 | * Note, despite the name, this returns the tgid not the pid. The tgid and | |
937 | * the pid are identical unless CLONE_THREAD was specified on clone() in | |
938 | * which case the tgid is the same in all threads of the same group. | |
939 | * | |
940 | * This is SMP safe as current->tgid does not change. | |
941 | */ | |
942 | asmlinkage long sys_getpid(void) | |
943 | { | |
944 | return current->tgid; | |
945 | } | |
946 | ||
947 | /* | |
948 | * Accessing ->group_leader->real_parent is not SMP-safe, it could | |
949 | * change from under us. However, rather than getting any lock | |
950 | * we can use an optimistic algorithm: get the parent | |
951 | * pid, and go back and check that the parent is still | |
952 | * the same. If it has changed (which is extremely unlikely | |
953 | * indeed), we just try again.. | |
954 | * | |
955 | * NOTE! This depends on the fact that even if we _do_ | |
956 | * get an old value of "parent", we can happily dereference | |
957 | * the pointer (it was and remains a dereferencable kernel pointer | |
958 | * no matter what): we just can't necessarily trust the result | |
959 | * until we know that the parent pointer is valid. | |
960 | * | |
961 | * NOTE2: ->group_leader never changes from under us. | |
962 | */ | |
963 | asmlinkage long sys_getppid(void) | |
964 | { | |
965 | int pid; | |
966 | struct task_struct *me = current; | |
967 | struct task_struct *parent; | |
968 | ||
969 | parent = me->group_leader->real_parent; | |
970 | for (;;) { | |
971 | pid = parent->tgid; | |
4c5640cb | 972 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) |
1da177e4 LT |
973 | { |
974 | struct task_struct *old = parent; | |
975 | ||
976 | /* | |
977 | * Make sure we read the pid before re-reading the | |
978 | * parent pointer: | |
979 | */ | |
d59dd462 | 980 | smp_rmb(); |
1da177e4 LT |
981 | parent = me->group_leader->real_parent; |
982 | if (old != parent) | |
983 | continue; | |
984 | } | |
985 | #endif | |
986 | break; | |
987 | } | |
988 | return pid; | |
989 | } | |
990 | ||
991 | asmlinkage long sys_getuid(void) | |
992 | { | |
993 | /* Only we change this so SMP safe */ | |
994 | return current->uid; | |
995 | } | |
996 | ||
997 | asmlinkage long sys_geteuid(void) | |
998 | { | |
999 | /* Only we change this so SMP safe */ | |
1000 | return current->euid; | |
1001 | } | |
1002 | ||
1003 | asmlinkage long sys_getgid(void) | |
1004 | { | |
1005 | /* Only we change this so SMP safe */ | |
1006 | return current->gid; | |
1007 | } | |
1008 | ||
1009 | asmlinkage long sys_getegid(void) | |
1010 | { | |
1011 | /* Only we change this so SMP safe */ | |
1012 | return current->egid; | |
1013 | } | |
1014 | ||
1015 | #endif | |
1016 | ||
1017 | static void process_timeout(unsigned long __data) | |
1018 | { | |
1019 | wake_up_process((task_t *)__data); | |
1020 | } | |
1021 | ||
1022 | /** | |
1023 | * schedule_timeout - sleep until timeout | |
1024 | * @timeout: timeout value in jiffies | |
1025 | * | |
1026 | * Make the current task sleep until @timeout jiffies have | |
1027 | * elapsed. The routine will return immediately unless | |
1028 | * the current task state has been set (see set_current_state()). | |
1029 | * | |
1030 | * You can set the task state as follows - | |
1031 | * | |
1032 | * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to | |
1033 | * pass before the routine returns. The routine will return 0 | |
1034 | * | |
1035 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
1036 | * delivered to the current task. In this case the remaining time | |
1037 | * in jiffies will be returned, or 0 if the timer expired in time | |
1038 | * | |
1039 | * The current task state is guaranteed to be TASK_RUNNING when this | |
1040 | * routine returns. | |
1041 | * | |
1042 | * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule | |
1043 | * the CPU away without a bound on the timeout. In this case the return | |
1044 | * value will be %MAX_SCHEDULE_TIMEOUT. | |
1045 | * | |
1046 | * In all cases the return value is guaranteed to be non-negative. | |
1047 | */ | |
1048 | fastcall signed long __sched schedule_timeout(signed long timeout) | |
1049 | { | |
1050 | struct timer_list timer; | |
1051 | unsigned long expire; | |
1052 | ||
1053 | switch (timeout) | |
1054 | { | |
1055 | case MAX_SCHEDULE_TIMEOUT: | |
1056 | /* | |
1057 | * These two special cases are useful to be comfortable | |
1058 | * in the caller. Nothing more. We could take | |
1059 | * MAX_SCHEDULE_TIMEOUT from one of the negative value | |
1060 | * but I' d like to return a valid offset (>=0) to allow | |
1061 | * the caller to do everything it want with the retval. | |
1062 | */ | |
1063 | schedule(); | |
1064 | goto out; | |
1065 | default: | |
1066 | /* | |
1067 | * Another bit of PARANOID. Note that the retval will be | |
1068 | * 0 since no piece of kernel is supposed to do a check | |
1069 | * for a negative retval of schedule_timeout() (since it | |
1070 | * should never happens anyway). You just have the printk() | |
1071 | * that will tell you if something is gone wrong and where. | |
1072 | */ | |
1073 | if (timeout < 0) | |
1074 | { | |
1075 | printk(KERN_ERR "schedule_timeout: wrong timeout " | |
a5a0d52c AM |
1076 | "value %lx from %p\n", timeout, |
1077 | __builtin_return_address(0)); | |
1da177e4 LT |
1078 | current->state = TASK_RUNNING; |
1079 | goto out; | |
1080 | } | |
1081 | } | |
1082 | ||
1083 | expire = timeout + jiffies; | |
1084 | ||
a8db2db1 ON |
1085 | setup_timer(&timer, process_timeout, (unsigned long)current); |
1086 | __mod_timer(&timer, expire); | |
1da177e4 LT |
1087 | schedule(); |
1088 | del_singleshot_timer_sync(&timer); | |
1089 | ||
1090 | timeout = expire - jiffies; | |
1091 | ||
1092 | out: | |
1093 | return timeout < 0 ? 0 : timeout; | |
1094 | } | |
1da177e4 LT |
1095 | EXPORT_SYMBOL(schedule_timeout); |
1096 | ||
8a1c1757 AM |
1097 | /* |
1098 | * We can use __set_current_state() here because schedule_timeout() calls | |
1099 | * schedule() unconditionally. | |
1100 | */ | |
64ed93a2 NA |
1101 | signed long __sched schedule_timeout_interruptible(signed long timeout) |
1102 | { | |
a5a0d52c AM |
1103 | __set_current_state(TASK_INTERRUPTIBLE); |
1104 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1105 | } |
1106 | EXPORT_SYMBOL(schedule_timeout_interruptible); | |
1107 | ||
1108 | signed long __sched schedule_timeout_uninterruptible(signed long timeout) | |
1109 | { | |
a5a0d52c AM |
1110 | __set_current_state(TASK_UNINTERRUPTIBLE); |
1111 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1112 | } |
1113 | EXPORT_SYMBOL(schedule_timeout_uninterruptible); | |
1114 | ||
1da177e4 LT |
1115 | /* Thread ID - the internal kernel "pid" */ |
1116 | asmlinkage long sys_gettid(void) | |
1117 | { | |
1118 | return current->pid; | |
1119 | } | |
1120 | ||
1121 | static long __sched nanosleep_restart(struct restart_block *restart) | |
1122 | { | |
1123 | unsigned long expire = restart->arg0, now = jiffies; | |
1124 | struct timespec __user *rmtp = (struct timespec __user *) restart->arg1; | |
1125 | long ret; | |
1126 | ||
1127 | /* Did it expire while we handled signals? */ | |
1128 | if (!time_after(expire, now)) | |
1129 | return 0; | |
1130 | ||
75bcc8c5 | 1131 | expire = schedule_timeout_interruptible(expire - now); |
1da177e4 LT |
1132 | |
1133 | ret = 0; | |
1134 | if (expire) { | |
1135 | struct timespec t; | |
1136 | jiffies_to_timespec(expire, &t); | |
1137 | ||
1138 | ret = -ERESTART_RESTARTBLOCK; | |
1139 | if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) | |
1140 | ret = -EFAULT; | |
1141 | /* The 'restart' block is already filled in */ | |
1142 | } | |
1143 | return ret; | |
1144 | } | |
1145 | ||
1146 | asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) | |
1147 | { | |
1148 | struct timespec t; | |
1149 | unsigned long expire; | |
1150 | long ret; | |
1151 | ||
1152 | if (copy_from_user(&t, rqtp, sizeof(t))) | |
1153 | return -EFAULT; | |
1154 | ||
1155 | if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0)) | |
1156 | return -EINVAL; | |
1157 | ||
1158 | expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec); | |
75bcc8c5 | 1159 | expire = schedule_timeout_interruptible(expire); |
1da177e4 LT |
1160 | |
1161 | ret = 0; | |
1162 | if (expire) { | |
1163 | struct restart_block *restart; | |
1164 | jiffies_to_timespec(expire, &t); | |
1165 | if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) | |
1166 | return -EFAULT; | |
1167 | ||
1168 | restart = ¤t_thread_info()->restart_block; | |
1169 | restart->fn = nanosleep_restart; | |
1170 | restart->arg0 = jiffies + expire; | |
1171 | restart->arg1 = (unsigned long) rmtp; | |
1172 | ret = -ERESTART_RESTARTBLOCK; | |
1173 | } | |
1174 | return ret; | |
1175 | } | |
1176 | ||
1177 | /* | |
1178 | * sys_sysinfo - fill in sysinfo struct | |
1179 | */ | |
1180 | asmlinkage long sys_sysinfo(struct sysinfo __user *info) | |
1181 | { | |
1182 | struct sysinfo val; | |
1183 | unsigned long mem_total, sav_total; | |
1184 | unsigned int mem_unit, bitcount; | |
1185 | unsigned long seq; | |
1186 | ||
1187 | memset((char *)&val, 0, sizeof(struct sysinfo)); | |
1188 | ||
1189 | do { | |
1190 | struct timespec tp; | |
1191 | seq = read_seqbegin(&xtime_lock); | |
1192 | ||
1193 | /* | |
1194 | * This is annoying. The below is the same thing | |
1195 | * posix_get_clock_monotonic() does, but it wants to | |
1196 | * take the lock which we want to cover the loads stuff | |
1197 | * too. | |
1198 | */ | |
1199 | ||
1200 | getnstimeofday(&tp); | |
1201 | tp.tv_sec += wall_to_monotonic.tv_sec; | |
1202 | tp.tv_nsec += wall_to_monotonic.tv_nsec; | |
1203 | if (tp.tv_nsec - NSEC_PER_SEC >= 0) { | |
1204 | tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC; | |
1205 | tp.tv_sec++; | |
1206 | } | |
1207 | val.uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); | |
1208 | ||
1209 | val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT); | |
1210 | val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT); | |
1211 | val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT); | |
1212 | ||
1213 | val.procs = nr_threads; | |
1214 | } while (read_seqretry(&xtime_lock, seq)); | |
1215 | ||
1216 | si_meminfo(&val); | |
1217 | si_swapinfo(&val); | |
1218 | ||
1219 | /* | |
1220 | * If the sum of all the available memory (i.e. ram + swap) | |
1221 | * is less than can be stored in a 32 bit unsigned long then | |
1222 | * we can be binary compatible with 2.2.x kernels. If not, | |
1223 | * well, in that case 2.2.x was broken anyways... | |
1224 | * | |
1225 | * -Erik Andersen <andersee@debian.org> | |
1226 | */ | |
1227 | ||
1228 | mem_total = val.totalram + val.totalswap; | |
1229 | if (mem_total < val.totalram || mem_total < val.totalswap) | |
1230 | goto out; | |
1231 | bitcount = 0; | |
1232 | mem_unit = val.mem_unit; | |
1233 | while (mem_unit > 1) { | |
1234 | bitcount++; | |
1235 | mem_unit >>= 1; | |
1236 | sav_total = mem_total; | |
1237 | mem_total <<= 1; | |
1238 | if (mem_total < sav_total) | |
1239 | goto out; | |
1240 | } | |
1241 | ||
1242 | /* | |
1243 | * If mem_total did not overflow, multiply all memory values by | |
1244 | * val.mem_unit and set it to 1. This leaves things compatible | |
1245 | * with 2.2.x, and also retains compatibility with earlier 2.4.x | |
1246 | * kernels... | |
1247 | */ | |
1248 | ||
1249 | val.mem_unit = 1; | |
1250 | val.totalram <<= bitcount; | |
1251 | val.freeram <<= bitcount; | |
1252 | val.sharedram <<= bitcount; | |
1253 | val.bufferram <<= bitcount; | |
1254 | val.totalswap <<= bitcount; | |
1255 | val.freeswap <<= bitcount; | |
1256 | val.totalhigh <<= bitcount; | |
1257 | val.freehigh <<= bitcount; | |
1258 | ||
1259 | out: | |
1260 | if (copy_to_user(info, &val, sizeof(struct sysinfo))) | |
1261 | return -EFAULT; | |
1262 | ||
1263 | return 0; | |
1264 | } | |
1265 | ||
1266 | static void __devinit init_timers_cpu(int cpu) | |
1267 | { | |
1268 | int j; | |
1269 | tvec_base_t *base; | |
55c888d6 | 1270 | |
1da177e4 | 1271 | base = &per_cpu(tvec_bases, cpu); |
55c888d6 | 1272 | spin_lock_init(&base->t_base.lock); |
1da177e4 LT |
1273 | for (j = 0; j < TVN_SIZE; j++) { |
1274 | INIT_LIST_HEAD(base->tv5.vec + j); | |
1275 | INIT_LIST_HEAD(base->tv4.vec + j); | |
1276 | INIT_LIST_HEAD(base->tv3.vec + j); | |
1277 | INIT_LIST_HEAD(base->tv2.vec + j); | |
1278 | } | |
1279 | for (j = 0; j < TVR_SIZE; j++) | |
1280 | INIT_LIST_HEAD(base->tv1.vec + j); | |
1281 | ||
1282 | base->timer_jiffies = jiffies; | |
1283 | } | |
1284 | ||
1285 | #ifdef CONFIG_HOTPLUG_CPU | |
55c888d6 | 1286 | static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head) |
1da177e4 LT |
1287 | { |
1288 | struct timer_list *timer; | |
1289 | ||
1290 | while (!list_empty(head)) { | |
1291 | timer = list_entry(head->next, struct timer_list, entry); | |
55c888d6 ON |
1292 | detach_timer(timer, 0); |
1293 | timer->base = &new_base->t_base; | |
1da177e4 | 1294 | internal_add_timer(new_base, timer); |
1da177e4 | 1295 | } |
1da177e4 LT |
1296 | } |
1297 | ||
1298 | static void __devinit migrate_timers(int cpu) | |
1299 | { | |
1300 | tvec_base_t *old_base; | |
1301 | tvec_base_t *new_base; | |
1302 | int i; | |
1303 | ||
1304 | BUG_ON(cpu_online(cpu)); | |
1305 | old_base = &per_cpu(tvec_bases, cpu); | |
1306 | new_base = &get_cpu_var(tvec_bases); | |
1307 | ||
1308 | local_irq_disable(); | |
55c888d6 ON |
1309 | spin_lock(&new_base->t_base.lock); |
1310 | spin_lock(&old_base->t_base.lock); | |
1da177e4 | 1311 | |
55c888d6 | 1312 | if (old_base->t_base.running_timer) |
1da177e4 LT |
1313 | BUG(); |
1314 | for (i = 0; i < TVR_SIZE; i++) | |
55c888d6 ON |
1315 | migrate_timer_list(new_base, old_base->tv1.vec + i); |
1316 | for (i = 0; i < TVN_SIZE; i++) { | |
1317 | migrate_timer_list(new_base, old_base->tv2.vec + i); | |
1318 | migrate_timer_list(new_base, old_base->tv3.vec + i); | |
1319 | migrate_timer_list(new_base, old_base->tv4.vec + i); | |
1320 | migrate_timer_list(new_base, old_base->tv5.vec + i); | |
1321 | } | |
1322 | ||
1323 | spin_unlock(&old_base->t_base.lock); | |
1324 | spin_unlock(&new_base->t_base.lock); | |
1da177e4 LT |
1325 | local_irq_enable(); |
1326 | put_cpu_var(tvec_bases); | |
1da177e4 LT |
1327 | } |
1328 | #endif /* CONFIG_HOTPLUG_CPU */ | |
1329 | ||
1330 | static int __devinit timer_cpu_notify(struct notifier_block *self, | |
1331 | unsigned long action, void *hcpu) | |
1332 | { | |
1333 | long cpu = (long)hcpu; | |
1334 | switch(action) { | |
1335 | case CPU_UP_PREPARE: | |
1336 | init_timers_cpu(cpu); | |
1337 | break; | |
1338 | #ifdef CONFIG_HOTPLUG_CPU | |
1339 | case CPU_DEAD: | |
1340 | migrate_timers(cpu); | |
1341 | break; | |
1342 | #endif | |
1343 | default: | |
1344 | break; | |
1345 | } | |
1346 | return NOTIFY_OK; | |
1347 | } | |
1348 | ||
1349 | static struct notifier_block __devinitdata timers_nb = { | |
1350 | .notifier_call = timer_cpu_notify, | |
1351 | }; | |
1352 | ||
1353 | ||
1354 | void __init init_timers(void) | |
1355 | { | |
1356 | timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, | |
1357 | (void *)(long)smp_processor_id()); | |
1358 | register_cpu_notifier(&timers_nb); | |
1359 | open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); | |
1360 | } | |
1361 | ||
1362 | #ifdef CONFIG_TIME_INTERPOLATION | |
1363 | ||
1364 | struct time_interpolator *time_interpolator; | |
1365 | static struct time_interpolator *time_interpolator_list; | |
1366 | static DEFINE_SPINLOCK(time_interpolator_lock); | |
1367 | ||
1368 | static inline u64 time_interpolator_get_cycles(unsigned int src) | |
1369 | { | |
1370 | unsigned long (*x)(void); | |
1371 | ||
1372 | switch (src) | |
1373 | { | |
1374 | case TIME_SOURCE_FUNCTION: | |
1375 | x = time_interpolator->addr; | |
1376 | return x(); | |
1377 | ||
1378 | case TIME_SOURCE_MMIO64 : | |
1379 | return readq((void __iomem *) time_interpolator->addr); | |
1380 | ||
1381 | case TIME_SOURCE_MMIO32 : | |
1382 | return readl((void __iomem *) time_interpolator->addr); | |
1383 | ||
1384 | default: return get_cycles(); | |
1385 | } | |
1386 | } | |
1387 | ||
486d46ae | 1388 | static inline u64 time_interpolator_get_counter(int writelock) |
1da177e4 LT |
1389 | { |
1390 | unsigned int src = time_interpolator->source; | |
1391 | ||
1392 | if (time_interpolator->jitter) | |
1393 | { | |
1394 | u64 lcycle; | |
1395 | u64 now; | |
1396 | ||
1397 | do { | |
1398 | lcycle = time_interpolator->last_cycle; | |
1399 | now = time_interpolator_get_cycles(src); | |
1400 | if (lcycle && time_after(lcycle, now)) | |
1401 | return lcycle; | |
486d46ae AW |
1402 | |
1403 | /* When holding the xtime write lock, there's no need | |
1404 | * to add the overhead of the cmpxchg. Readers are | |
1405 | * force to retry until the write lock is released. | |
1406 | */ | |
1407 | if (writelock) { | |
1408 | time_interpolator->last_cycle = now; | |
1409 | return now; | |
1410 | } | |
1da177e4 LT |
1411 | /* Keep track of the last timer value returned. The use of cmpxchg here |
1412 | * will cause contention in an SMP environment. | |
1413 | */ | |
1414 | } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle)); | |
1415 | return now; | |
1416 | } | |
1417 | else | |
1418 | return time_interpolator_get_cycles(src); | |
1419 | } | |
1420 | ||
1421 | void time_interpolator_reset(void) | |
1422 | { | |
1423 | time_interpolator->offset = 0; | |
486d46ae | 1424 | time_interpolator->last_counter = time_interpolator_get_counter(1); |
1da177e4 LT |
1425 | } |
1426 | ||
1427 | #define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift) | |
1428 | ||
1429 | unsigned long time_interpolator_get_offset(void) | |
1430 | { | |
1431 | /* If we do not have a time interpolator set up then just return zero */ | |
1432 | if (!time_interpolator) | |
1433 | return 0; | |
1434 | ||
1435 | return time_interpolator->offset + | |
486d46ae | 1436 | GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator); |
1da177e4 LT |
1437 | } |
1438 | ||
1439 | #define INTERPOLATOR_ADJUST 65536 | |
1440 | #define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST | |
1441 | ||
1442 | static void time_interpolator_update(long delta_nsec) | |
1443 | { | |
1444 | u64 counter; | |
1445 | unsigned long offset; | |
1446 | ||
1447 | /* If there is no time interpolator set up then do nothing */ | |
1448 | if (!time_interpolator) | |
1449 | return; | |
1450 | ||
a5a0d52c AM |
1451 | /* |
1452 | * The interpolator compensates for late ticks by accumulating the late | |
1453 | * time in time_interpolator->offset. A tick earlier than expected will | |
1454 | * lead to a reset of the offset and a corresponding jump of the clock | |
1455 | * forward. Again this only works if the interpolator clock is running | |
1456 | * slightly slower than the regular clock and the tuning logic insures | |
1457 | * that. | |
1458 | */ | |
1da177e4 | 1459 | |
486d46ae | 1460 | counter = time_interpolator_get_counter(1); |
a5a0d52c AM |
1461 | offset = time_interpolator->offset + |
1462 | GET_TI_NSECS(counter, time_interpolator); | |
1da177e4 LT |
1463 | |
1464 | if (delta_nsec < 0 || (unsigned long) delta_nsec < offset) | |
1465 | time_interpolator->offset = offset - delta_nsec; | |
1466 | else { | |
1467 | time_interpolator->skips++; | |
1468 | time_interpolator->ns_skipped += delta_nsec - offset; | |
1469 | time_interpolator->offset = 0; | |
1470 | } | |
1471 | time_interpolator->last_counter = counter; | |
1472 | ||
1473 | /* Tuning logic for time interpolator invoked every minute or so. | |
1474 | * Decrease interpolator clock speed if no skips occurred and an offset is carried. | |
1475 | * Increase interpolator clock speed if we skip too much time. | |
1476 | */ | |
1477 | if (jiffies % INTERPOLATOR_ADJUST == 0) | |
1478 | { | |
1479 | if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC) | |
1480 | time_interpolator->nsec_per_cyc--; | |
1481 | if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0) | |
1482 | time_interpolator->nsec_per_cyc++; | |
1483 | time_interpolator->skips = 0; | |
1484 | time_interpolator->ns_skipped = 0; | |
1485 | } | |
1486 | } | |
1487 | ||
1488 | static inline int | |
1489 | is_better_time_interpolator(struct time_interpolator *new) | |
1490 | { | |
1491 | if (!time_interpolator) | |
1492 | return 1; | |
1493 | return new->frequency > 2*time_interpolator->frequency || | |
1494 | (unsigned long)new->drift < (unsigned long)time_interpolator->drift; | |
1495 | } | |
1496 | ||
1497 | void | |
1498 | register_time_interpolator(struct time_interpolator *ti) | |
1499 | { | |
1500 | unsigned long flags; | |
1501 | ||
1502 | /* Sanity check */ | |
1503 | if (ti->frequency == 0 || ti->mask == 0) | |
1504 | BUG(); | |
1505 | ||
1506 | ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency; | |
1507 | spin_lock(&time_interpolator_lock); | |
1508 | write_seqlock_irqsave(&xtime_lock, flags); | |
1509 | if (is_better_time_interpolator(ti)) { | |
1510 | time_interpolator = ti; | |
1511 | time_interpolator_reset(); | |
1512 | } | |
1513 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1514 | ||
1515 | ti->next = time_interpolator_list; | |
1516 | time_interpolator_list = ti; | |
1517 | spin_unlock(&time_interpolator_lock); | |
1518 | } | |
1519 | ||
1520 | void | |
1521 | unregister_time_interpolator(struct time_interpolator *ti) | |
1522 | { | |
1523 | struct time_interpolator *curr, **prev; | |
1524 | unsigned long flags; | |
1525 | ||
1526 | spin_lock(&time_interpolator_lock); | |
1527 | prev = &time_interpolator_list; | |
1528 | for (curr = *prev; curr; curr = curr->next) { | |
1529 | if (curr == ti) { | |
1530 | *prev = curr->next; | |
1531 | break; | |
1532 | } | |
1533 | prev = &curr->next; | |
1534 | } | |
1535 | ||
1536 | write_seqlock_irqsave(&xtime_lock, flags); | |
1537 | if (ti == time_interpolator) { | |
1538 | /* we lost the best time-interpolator: */ | |
1539 | time_interpolator = NULL; | |
1540 | /* find the next-best interpolator */ | |
1541 | for (curr = time_interpolator_list; curr; curr = curr->next) | |
1542 | if (is_better_time_interpolator(curr)) | |
1543 | time_interpolator = curr; | |
1544 | time_interpolator_reset(); | |
1545 | } | |
1546 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1547 | spin_unlock(&time_interpolator_lock); | |
1548 | } | |
1549 | #endif /* CONFIG_TIME_INTERPOLATION */ | |
1550 | ||
1551 | /** | |
1552 | * msleep - sleep safely even with waitqueue interruptions | |
1553 | * @msecs: Time in milliseconds to sleep for | |
1554 | */ | |
1555 | void msleep(unsigned int msecs) | |
1556 | { | |
1557 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1558 | ||
75bcc8c5 NA |
1559 | while (timeout) |
1560 | timeout = schedule_timeout_uninterruptible(timeout); | |
1da177e4 LT |
1561 | } |
1562 | ||
1563 | EXPORT_SYMBOL(msleep); | |
1564 | ||
1565 | /** | |
96ec3efd | 1566 | * msleep_interruptible - sleep waiting for signals |
1da177e4 LT |
1567 | * @msecs: Time in milliseconds to sleep for |
1568 | */ | |
1569 | unsigned long msleep_interruptible(unsigned int msecs) | |
1570 | { | |
1571 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1572 | ||
75bcc8c5 NA |
1573 | while (timeout && !signal_pending(current)) |
1574 | timeout = schedule_timeout_interruptible(timeout); | |
1da177e4 LT |
1575 | return jiffies_to_msecs(timeout); |
1576 | } | |
1577 | ||
1578 | EXPORT_SYMBOL(msleep_interruptible); |