]>
Commit | Line | Data |
---|---|---|
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 | ||
49 | /* | |
50 | * per-CPU timer vector definitions: | |
51 | */ | |
52 | ||
53 | #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) | |
54 | #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) | |
55 | #define TVN_SIZE (1 << TVN_BITS) | |
56 | #define TVR_SIZE (1 << TVR_BITS) | |
57 | #define TVN_MASK (TVN_SIZE - 1) | |
58 | #define TVR_MASK (TVR_SIZE - 1) | |
59 | ||
60 | typedef struct tvec_s { | |
61 | struct list_head vec[TVN_SIZE]; | |
62 | } tvec_t; | |
63 | ||
64 | typedef struct tvec_root_s { | |
65 | struct list_head vec[TVR_SIZE]; | |
66 | } tvec_root_t; | |
67 | ||
68 | struct tvec_t_base_s { | |
69 | spinlock_t lock; | |
70 | unsigned long timer_jiffies; | |
71 | struct timer_list *running_timer; | |
72 | tvec_root_t tv1; | |
73 | tvec_t tv2; | |
74 | tvec_t tv3; | |
75 | tvec_t tv4; | |
76 | tvec_t tv5; | |
77 | } ____cacheline_aligned_in_smp; | |
78 | ||
79 | typedef struct tvec_t_base_s tvec_base_t; | |
80 | ||
81 | static inline void set_running_timer(tvec_base_t *base, | |
82 | struct timer_list *timer) | |
83 | { | |
84 | #ifdef CONFIG_SMP | |
85 | base->running_timer = timer; | |
86 | #endif | |
87 | } | |
88 | ||
89 | /* Fake initialization */ | |
90 | static DEFINE_PER_CPU(tvec_base_t, tvec_bases) = { SPIN_LOCK_UNLOCKED }; | |
91 | ||
92 | static void check_timer_failed(struct timer_list *timer) | |
93 | { | |
94 | static int whine_count; | |
95 | if (whine_count < 16) { | |
96 | whine_count++; | |
97 | printk("Uninitialised timer!\n"); | |
98 | printk("This is just a warning. Your computer is OK\n"); | |
99 | printk("function=0x%p, data=0x%lx\n", | |
100 | timer->function, timer->data); | |
101 | dump_stack(); | |
102 | } | |
103 | /* | |
104 | * Now fix it up | |
105 | */ | |
106 | spin_lock_init(&timer->lock); | |
107 | timer->magic = TIMER_MAGIC; | |
108 | } | |
109 | ||
110 | static inline void check_timer(struct timer_list *timer) | |
111 | { | |
112 | if (timer->magic != TIMER_MAGIC) | |
113 | check_timer_failed(timer); | |
114 | } | |
115 | ||
116 | ||
117 | static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) | |
118 | { | |
119 | unsigned long expires = timer->expires; | |
120 | unsigned long idx = expires - base->timer_jiffies; | |
121 | struct list_head *vec; | |
122 | ||
123 | if (idx < TVR_SIZE) { | |
124 | int i = expires & TVR_MASK; | |
125 | vec = base->tv1.vec + i; | |
126 | } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { | |
127 | int i = (expires >> TVR_BITS) & TVN_MASK; | |
128 | vec = base->tv2.vec + i; | |
129 | } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { | |
130 | int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; | |
131 | vec = base->tv3.vec + i; | |
132 | } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { | |
133 | int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; | |
134 | vec = base->tv4.vec + i; | |
135 | } else if ((signed long) idx < 0) { | |
136 | /* | |
137 | * Can happen if you add a timer with expires == jiffies, | |
138 | * or you set a timer to go off in the past | |
139 | */ | |
140 | vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); | |
141 | } else { | |
142 | int i; | |
143 | /* If the timeout is larger than 0xffffffff on 64-bit | |
144 | * architectures then we use the maximum timeout: | |
145 | */ | |
146 | if (idx > 0xffffffffUL) { | |
147 | idx = 0xffffffffUL; | |
148 | expires = idx + base->timer_jiffies; | |
149 | } | |
150 | i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; | |
151 | vec = base->tv5.vec + i; | |
152 | } | |
153 | /* | |
154 | * Timers are FIFO: | |
155 | */ | |
156 | list_add_tail(&timer->entry, vec); | |
157 | } | |
158 | ||
159 | int __mod_timer(struct timer_list *timer, unsigned long expires) | |
160 | { | |
161 | tvec_base_t *old_base, *new_base; | |
162 | unsigned long flags; | |
163 | int ret = 0; | |
164 | ||
165 | BUG_ON(!timer->function); | |
166 | ||
167 | check_timer(timer); | |
168 | ||
169 | spin_lock_irqsave(&timer->lock, flags); | |
170 | new_base = &__get_cpu_var(tvec_bases); | |
171 | repeat: | |
172 | old_base = timer->base; | |
173 | ||
174 | /* | |
175 | * Prevent deadlocks via ordering by old_base < new_base. | |
176 | */ | |
177 | if (old_base && (new_base != old_base)) { | |
178 | if (old_base < new_base) { | |
179 | spin_lock(&new_base->lock); | |
180 | spin_lock(&old_base->lock); | |
181 | } else { | |
182 | spin_lock(&old_base->lock); | |
183 | spin_lock(&new_base->lock); | |
184 | } | |
185 | /* | |
186 | * The timer base might have been cancelled while we were | |
187 | * trying to take the lock(s): | |
188 | */ | |
189 | if (timer->base != old_base) { | |
190 | spin_unlock(&new_base->lock); | |
191 | spin_unlock(&old_base->lock); | |
192 | goto repeat; | |
193 | } | |
194 | } else { | |
195 | spin_lock(&new_base->lock); | |
196 | if (timer->base != old_base) { | |
197 | spin_unlock(&new_base->lock); | |
198 | goto repeat; | |
199 | } | |
200 | } | |
201 | ||
202 | /* | |
203 | * Delete the previous timeout (if there was any), and install | |
204 | * the new one: | |
205 | */ | |
206 | if (old_base) { | |
207 | list_del(&timer->entry); | |
208 | ret = 1; | |
209 | } | |
210 | timer->expires = expires; | |
211 | internal_add_timer(new_base, timer); | |
212 | timer->base = new_base; | |
213 | ||
214 | if (old_base && (new_base != old_base)) | |
215 | spin_unlock(&old_base->lock); | |
216 | spin_unlock(&new_base->lock); | |
217 | spin_unlock_irqrestore(&timer->lock, flags); | |
218 | ||
219 | return ret; | |
220 | } | |
221 | ||
222 | EXPORT_SYMBOL(__mod_timer); | |
223 | ||
224 | /*** | |
225 | * add_timer_on - start a timer on a particular CPU | |
226 | * @timer: the timer to be added | |
227 | * @cpu: the CPU to start it on | |
228 | * | |
229 | * This is not very scalable on SMP. Double adds are not possible. | |
230 | */ | |
231 | void add_timer_on(struct timer_list *timer, int cpu) | |
232 | { | |
233 | tvec_base_t *base = &per_cpu(tvec_bases, cpu); | |
234 | unsigned long flags; | |
235 | ||
236 | BUG_ON(timer_pending(timer) || !timer->function); | |
237 | ||
238 | check_timer(timer); | |
239 | ||
240 | spin_lock_irqsave(&base->lock, flags); | |
241 | internal_add_timer(base, timer); | |
242 | timer->base = base; | |
243 | spin_unlock_irqrestore(&base->lock, flags); | |
244 | } | |
245 | ||
246 | ||
247 | /*** | |
248 | * mod_timer - modify a timer's timeout | |
249 | * @timer: the timer to be modified | |
250 | * | |
251 | * mod_timer is a more efficient way to update the expire field of an | |
252 | * active timer (if the timer is inactive it will be activated) | |
253 | * | |
254 | * mod_timer(timer, expires) is equivalent to: | |
255 | * | |
256 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
257 | * | |
258 | * Note that if there are multiple unserialized concurrent users of the | |
259 | * same timer, then mod_timer() is the only safe way to modify the timeout, | |
260 | * since add_timer() cannot modify an already running timer. | |
261 | * | |
262 | * The function returns whether it has modified a pending timer or not. | |
263 | * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an | |
264 | * active timer returns 1.) | |
265 | */ | |
266 | int mod_timer(struct timer_list *timer, unsigned long expires) | |
267 | { | |
268 | BUG_ON(!timer->function); | |
269 | ||
270 | check_timer(timer); | |
271 | ||
272 | /* | |
273 | * This is a common optimization triggered by the | |
274 | * networking code - if the timer is re-modified | |
275 | * to be the same thing then just return: | |
276 | */ | |
277 | if (timer->expires == expires && timer_pending(timer)) | |
278 | return 1; | |
279 | ||
280 | return __mod_timer(timer, expires); | |
281 | } | |
282 | ||
283 | EXPORT_SYMBOL(mod_timer); | |
284 | ||
285 | /*** | |
286 | * del_timer - deactive a timer. | |
287 | * @timer: the timer to be deactivated | |
288 | * | |
289 | * del_timer() deactivates a timer - this works on both active and inactive | |
290 | * timers. | |
291 | * | |
292 | * The function returns whether it has deactivated a pending timer or not. | |
293 | * (ie. del_timer() of an inactive timer returns 0, del_timer() of an | |
294 | * active timer returns 1.) | |
295 | */ | |
296 | int del_timer(struct timer_list *timer) | |
297 | { | |
298 | unsigned long flags; | |
299 | tvec_base_t *base; | |
300 | ||
301 | check_timer(timer); | |
302 | ||
303 | repeat: | |
304 | base = timer->base; | |
305 | if (!base) | |
306 | return 0; | |
307 | spin_lock_irqsave(&base->lock, flags); | |
308 | if (base != timer->base) { | |
309 | spin_unlock_irqrestore(&base->lock, flags); | |
310 | goto repeat; | |
311 | } | |
312 | list_del(&timer->entry); | |
313 | /* Need to make sure that anybody who sees a NULL base also sees the list ops */ | |
314 | smp_wmb(); | |
315 | timer->base = NULL; | |
316 | spin_unlock_irqrestore(&base->lock, flags); | |
317 | ||
318 | return 1; | |
319 | } | |
320 | ||
321 | EXPORT_SYMBOL(del_timer); | |
322 | ||
323 | #ifdef CONFIG_SMP | |
324 | /*** | |
325 | * del_timer_sync - deactivate a timer and wait for the handler to finish. | |
326 | * @timer: the timer to be deactivated | |
327 | * | |
328 | * This function only differs from del_timer() on SMP: besides deactivating | |
329 | * the timer it also makes sure the handler has finished executing on other | |
330 | * CPUs. | |
331 | * | |
332 | * Synchronization rules: callers must prevent restarting of the timer, | |
333 | * otherwise this function is meaningless. It must not be called from | |
334 | * interrupt contexts. The caller must not hold locks which would prevent | |
335 | * completion of the timer's handler. Upon exit the timer is not queued and | |
336 | * the handler is not running on any CPU. | |
337 | * | |
338 | * The function returns whether it has deactivated a pending timer or not. | |
339 | * | |
340 | * del_timer_sync() is slow and complicated because it copes with timer | |
341 | * handlers which re-arm the timer (periodic timers). If the timer handler | |
342 | * is known to not do this (a single shot timer) then use | |
343 | * del_singleshot_timer_sync() instead. | |
344 | */ | |
345 | int del_timer_sync(struct timer_list *timer) | |
346 | { | |
347 | tvec_base_t *base; | |
348 | int i, ret = 0; | |
349 | ||
350 | check_timer(timer); | |
351 | ||
352 | del_again: | |
353 | ret += del_timer(timer); | |
354 | ||
355 | for_each_online_cpu(i) { | |
356 | base = &per_cpu(tvec_bases, i); | |
357 | if (base->running_timer == timer) { | |
358 | while (base->running_timer == timer) { | |
359 | cpu_relax(); | |
360 | preempt_check_resched(); | |
361 | } | |
362 | break; | |
363 | } | |
364 | } | |
365 | smp_rmb(); | |
366 | if (timer_pending(timer)) | |
367 | goto del_again; | |
368 | ||
369 | return ret; | |
370 | } | |
371 | EXPORT_SYMBOL(del_timer_sync); | |
372 | ||
373 | /*** | |
374 | * del_singleshot_timer_sync - deactivate a non-recursive timer | |
375 | * @timer: the timer to be deactivated | |
376 | * | |
377 | * This function is an optimization of del_timer_sync for the case where the | |
378 | * caller can guarantee the timer does not reschedule itself in its timer | |
379 | * function. | |
380 | * | |
381 | * Synchronization rules: callers must prevent restarting of the timer, | |
382 | * otherwise this function is meaningless. It must not be called from | |
383 | * interrupt contexts. The caller must not hold locks which wold prevent | |
384 | * completion of the timer's handler. Upon exit the timer is not queued and | |
385 | * the handler is not running on any CPU. | |
386 | * | |
387 | * The function returns whether it has deactivated a pending timer or not. | |
388 | */ | |
389 | int del_singleshot_timer_sync(struct timer_list *timer) | |
390 | { | |
391 | int ret = del_timer(timer); | |
392 | ||
393 | if (!ret) { | |
394 | ret = del_timer_sync(timer); | |
395 | BUG_ON(ret); | |
396 | } | |
397 | ||
398 | return ret; | |
399 | } | |
400 | EXPORT_SYMBOL(del_singleshot_timer_sync); | |
401 | #endif | |
402 | ||
403 | static int cascade(tvec_base_t *base, tvec_t *tv, int index) | |
404 | { | |
405 | /* cascade all the timers from tv up one level */ | |
406 | struct list_head *head, *curr; | |
407 | ||
408 | head = tv->vec + index; | |
409 | curr = head->next; | |
410 | /* | |
411 | * We are removing _all_ timers from the list, so we don't have to | |
412 | * detach them individually, just clear the list afterwards. | |
413 | */ | |
414 | while (curr != head) { | |
415 | struct timer_list *tmp; | |
416 | ||
417 | tmp = list_entry(curr, struct timer_list, entry); | |
418 | BUG_ON(tmp->base != base); | |
419 | curr = curr->next; | |
420 | internal_add_timer(base, tmp); | |
421 | } | |
422 | INIT_LIST_HEAD(head); | |
423 | ||
424 | return index; | |
425 | } | |
426 | ||
427 | /*** | |
428 | * __run_timers - run all expired timers (if any) on this CPU. | |
429 | * @base: the timer vector to be processed. | |
430 | * | |
431 | * This function cascades all vectors and executes all expired timer | |
432 | * vectors. | |
433 | */ | |
434 | #define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK | |
435 | ||
436 | static inline void __run_timers(tvec_base_t *base) | |
437 | { | |
438 | struct timer_list *timer; | |
439 | ||
440 | spin_lock_irq(&base->lock); | |
441 | while (time_after_eq(jiffies, base->timer_jiffies)) { | |
442 | struct list_head work_list = LIST_HEAD_INIT(work_list); | |
443 | struct list_head *head = &work_list; | |
444 | int index = base->timer_jiffies & TVR_MASK; | |
445 | ||
446 | /* | |
447 | * Cascade timers: | |
448 | */ | |
449 | if (!index && | |
450 | (!cascade(base, &base->tv2, INDEX(0))) && | |
451 | (!cascade(base, &base->tv3, INDEX(1))) && | |
452 | !cascade(base, &base->tv4, INDEX(2))) | |
453 | cascade(base, &base->tv5, INDEX(3)); | |
454 | ++base->timer_jiffies; | |
455 | list_splice_init(base->tv1.vec + index, &work_list); | |
456 | repeat: | |
457 | if (!list_empty(head)) { | |
458 | void (*fn)(unsigned long); | |
459 | unsigned long data; | |
460 | ||
461 | timer = list_entry(head->next,struct timer_list,entry); | |
462 | fn = timer->function; | |
463 | data = timer->data; | |
464 | ||
465 | list_del(&timer->entry); | |
466 | set_running_timer(base, timer); | |
467 | smp_wmb(); | |
468 | timer->base = NULL; | |
469 | spin_unlock_irq(&base->lock); | |
470 | { | |
471 | u32 preempt_count = preempt_count(); | |
472 | fn(data); | |
473 | if (preempt_count != preempt_count()) { | |
474 | printk("huh, entered %p with %08x, exited with %08x?\n", fn, preempt_count, preempt_count()); | |
475 | BUG(); | |
476 | } | |
477 | } | |
478 | spin_lock_irq(&base->lock); | |
479 | goto repeat; | |
480 | } | |
481 | } | |
482 | set_running_timer(base, NULL); | |
483 | spin_unlock_irq(&base->lock); | |
484 | } | |
485 | ||
486 | #ifdef CONFIG_NO_IDLE_HZ | |
487 | /* | |
488 | * Find out when the next timer event is due to happen. This | |
489 | * is used on S/390 to stop all activity when a cpus is idle. | |
490 | * This functions needs to be called disabled. | |
491 | */ | |
492 | unsigned long next_timer_interrupt(void) | |
493 | { | |
494 | tvec_base_t *base; | |
495 | struct list_head *list; | |
496 | struct timer_list *nte; | |
497 | unsigned long expires; | |
498 | tvec_t *varray[4]; | |
499 | int i, j; | |
500 | ||
501 | base = &__get_cpu_var(tvec_bases); | |
502 | spin_lock(&base->lock); | |
503 | expires = base->timer_jiffies + (LONG_MAX >> 1); | |
504 | list = 0; | |
505 | ||
506 | /* Look for timer events in tv1. */ | |
507 | j = base->timer_jiffies & TVR_MASK; | |
508 | do { | |
509 | list_for_each_entry(nte, base->tv1.vec + j, entry) { | |
510 | expires = nte->expires; | |
511 | if (j < (base->timer_jiffies & TVR_MASK)) | |
512 | list = base->tv2.vec + (INDEX(0)); | |
513 | goto found; | |
514 | } | |
515 | j = (j + 1) & TVR_MASK; | |
516 | } while (j != (base->timer_jiffies & TVR_MASK)); | |
517 | ||
518 | /* Check tv2-tv5. */ | |
519 | varray[0] = &base->tv2; | |
520 | varray[1] = &base->tv3; | |
521 | varray[2] = &base->tv4; | |
522 | varray[3] = &base->tv5; | |
523 | for (i = 0; i < 4; i++) { | |
524 | j = INDEX(i); | |
525 | do { | |
526 | if (list_empty(varray[i]->vec + j)) { | |
527 | j = (j + 1) & TVN_MASK; | |
528 | continue; | |
529 | } | |
530 | list_for_each_entry(nte, varray[i]->vec + j, entry) | |
531 | if (time_before(nte->expires, expires)) | |
532 | expires = nte->expires; | |
533 | if (j < (INDEX(i)) && i < 3) | |
534 | list = varray[i + 1]->vec + (INDEX(i + 1)); | |
535 | goto found; | |
536 | } while (j != (INDEX(i))); | |
537 | } | |
538 | found: | |
539 | if (list) { | |
540 | /* | |
541 | * The search wrapped. We need to look at the next list | |
542 | * from next tv element that would cascade into tv element | |
543 | * where we found the timer element. | |
544 | */ | |
545 | list_for_each_entry(nte, list, entry) { | |
546 | if (time_before(nte->expires, expires)) | |
547 | expires = nte->expires; | |
548 | } | |
549 | } | |
550 | spin_unlock(&base->lock); | |
551 | return expires; | |
552 | } | |
553 | #endif | |
554 | ||
555 | /******************************************************************/ | |
556 | ||
557 | /* | |
558 | * Timekeeping variables | |
559 | */ | |
560 | unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */ | |
561 | unsigned long tick_nsec = TICK_NSEC; /* ACTHZ period (nsec) */ | |
562 | ||
563 | /* | |
564 | * The current time | |
565 | * wall_to_monotonic is what we need to add to xtime (or xtime corrected | |
566 | * for sub jiffie times) to get to monotonic time. Monotonic is pegged | |
567 | * at zero at system boot time, so wall_to_monotonic will be negative, | |
568 | * however, we will ALWAYS keep the tv_nsec part positive so we can use | |
569 | * the usual normalization. | |
570 | */ | |
571 | struct timespec xtime __attribute__ ((aligned (16))); | |
572 | struct timespec wall_to_monotonic __attribute__ ((aligned (16))); | |
573 | ||
574 | EXPORT_SYMBOL(xtime); | |
575 | ||
576 | /* Don't completely fail for HZ > 500. */ | |
577 | int tickadj = 500/HZ ? : 1; /* microsecs */ | |
578 | ||
579 | ||
580 | /* | |
581 | * phase-lock loop variables | |
582 | */ | |
583 | /* TIME_ERROR prevents overwriting the CMOS clock */ | |
584 | int time_state = TIME_OK; /* clock synchronization status */ | |
585 | int time_status = STA_UNSYNC; /* clock status bits */ | |
586 | long time_offset; /* time adjustment (us) */ | |
587 | long time_constant = 2; /* pll time constant */ | |
588 | long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */ | |
589 | long time_precision = 1; /* clock precision (us) */ | |
590 | long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ | |
591 | long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ | |
592 | static long time_phase; /* phase offset (scaled us) */ | |
593 | long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC; | |
594 | /* frequency offset (scaled ppm)*/ | |
595 | static long time_adj; /* tick adjust (scaled 1 / HZ) */ | |
596 | long time_reftime; /* time at last adjustment (s) */ | |
597 | long time_adjust; | |
598 | long time_next_adjust; | |
599 | ||
600 | /* | |
601 | * this routine handles the overflow of the microsecond field | |
602 | * | |
603 | * The tricky bits of code to handle the accurate clock support | |
604 | * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. | |
605 | * They were originally developed for SUN and DEC kernels. | |
606 | * All the kudos should go to Dave for this stuff. | |
607 | * | |
608 | */ | |
609 | static void second_overflow(void) | |
610 | { | |
611 | long ltemp; | |
612 | ||
613 | /* Bump the maxerror field */ | |
614 | time_maxerror += time_tolerance >> SHIFT_USEC; | |
615 | if ( time_maxerror > NTP_PHASE_LIMIT ) { | |
616 | time_maxerror = NTP_PHASE_LIMIT; | |
617 | time_status |= STA_UNSYNC; | |
618 | } | |
619 | ||
620 | /* | |
621 | * Leap second processing. If in leap-insert state at | |
622 | * the end of the day, the system clock is set back one | |
623 | * second; if in leap-delete state, the system clock is | |
624 | * set ahead one second. The microtime() routine or | |
625 | * external clock driver will insure that reported time | |
626 | * is always monotonic. The ugly divides should be | |
627 | * replaced. | |
628 | */ | |
629 | switch (time_state) { | |
630 | ||
631 | case TIME_OK: | |
632 | if (time_status & STA_INS) | |
633 | time_state = TIME_INS; | |
634 | else if (time_status & STA_DEL) | |
635 | time_state = TIME_DEL; | |
636 | break; | |
637 | ||
638 | case TIME_INS: | |
639 | if (xtime.tv_sec % 86400 == 0) { | |
640 | xtime.tv_sec--; | |
641 | wall_to_monotonic.tv_sec++; | |
642 | /* The timer interpolator will make time change gradually instead | |
643 | * of an immediate jump by one second. | |
644 | */ | |
645 | time_interpolator_update(-NSEC_PER_SEC); | |
646 | time_state = TIME_OOP; | |
647 | clock_was_set(); | |
648 | printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n"); | |
649 | } | |
650 | break; | |
651 | ||
652 | case TIME_DEL: | |
653 | if ((xtime.tv_sec + 1) % 86400 == 0) { | |
654 | xtime.tv_sec++; | |
655 | wall_to_monotonic.tv_sec--; | |
656 | /* Use of time interpolator for a gradual change of time */ | |
657 | time_interpolator_update(NSEC_PER_SEC); | |
658 | time_state = TIME_WAIT; | |
659 | clock_was_set(); | |
660 | printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n"); | |
661 | } | |
662 | break; | |
663 | ||
664 | case TIME_OOP: | |
665 | time_state = TIME_WAIT; | |
666 | break; | |
667 | ||
668 | case TIME_WAIT: | |
669 | if (!(time_status & (STA_INS | STA_DEL))) | |
670 | time_state = TIME_OK; | |
671 | } | |
672 | ||
673 | /* | |
674 | * Compute the phase adjustment for the next second. In | |
675 | * PLL mode, the offset is reduced by a fixed factor | |
676 | * times the time constant. In FLL mode the offset is | |
677 | * used directly. In either mode, the maximum phase | |
678 | * adjustment for each second is clamped so as to spread | |
679 | * the adjustment over not more than the number of | |
680 | * seconds between updates. | |
681 | */ | |
682 | if (time_offset < 0) { | |
683 | ltemp = -time_offset; | |
684 | if (!(time_status & STA_FLL)) | |
685 | ltemp >>= SHIFT_KG + time_constant; | |
686 | if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) | |
687 | ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; | |
688 | time_offset += ltemp; | |
689 | time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); | |
690 | } else { | |
691 | ltemp = time_offset; | |
692 | if (!(time_status & STA_FLL)) | |
693 | ltemp >>= SHIFT_KG + time_constant; | |
694 | if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) | |
695 | ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; | |
696 | time_offset -= ltemp; | |
697 | time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); | |
698 | } | |
699 | ||
700 | /* | |
701 | * Compute the frequency estimate and additional phase | |
702 | * adjustment due to frequency error for the next | |
703 | * second. When the PPS signal is engaged, gnaw on the | |
704 | * watchdog counter and update the frequency computed by | |
705 | * the pll and the PPS signal. | |
706 | */ | |
707 | pps_valid++; | |
708 | if (pps_valid == PPS_VALID) { /* PPS signal lost */ | |
709 | pps_jitter = MAXTIME; | |
710 | pps_stabil = MAXFREQ; | |
711 | time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | | |
712 | STA_PPSWANDER | STA_PPSERROR); | |
713 | } | |
714 | ltemp = time_freq + pps_freq; | |
715 | if (ltemp < 0) | |
716 | time_adj -= -ltemp >> | |
717 | (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); | |
718 | else | |
719 | time_adj += ltemp >> | |
720 | (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); | |
721 | ||
722 | #if HZ == 100 | |
723 | /* Compensate for (HZ==100) != (1 << SHIFT_HZ). | |
724 | * Add 25% and 3.125% to get 128.125; => only 0.125% error (p. 14) | |
725 | */ | |
726 | if (time_adj < 0) | |
727 | time_adj -= (-time_adj >> 2) + (-time_adj >> 5); | |
728 | else | |
729 | time_adj += (time_adj >> 2) + (time_adj >> 5); | |
730 | #endif | |
731 | #if HZ == 1000 | |
732 | /* Compensate for (HZ==1000) != (1 << SHIFT_HZ). | |
733 | * Add 1.5625% and 0.78125% to get 1023.4375; => only 0.05% error (p. 14) | |
734 | */ | |
735 | if (time_adj < 0) | |
736 | time_adj -= (-time_adj >> 6) + (-time_adj >> 7); | |
737 | else | |
738 | time_adj += (time_adj >> 6) + (time_adj >> 7); | |
739 | #endif | |
740 | } | |
741 | ||
742 | /* in the NTP reference this is called "hardclock()" */ | |
743 | static void update_wall_time_one_tick(void) | |
744 | { | |
745 | long time_adjust_step, delta_nsec; | |
746 | ||
747 | if ( (time_adjust_step = time_adjust) != 0 ) { | |
748 | /* We are doing an adjtime thing. | |
749 | * | |
750 | * Prepare time_adjust_step to be within bounds. | |
751 | * Note that a positive time_adjust means we want the clock | |
752 | * to run faster. | |
753 | * | |
754 | * Limit the amount of the step to be in the range | |
755 | * -tickadj .. +tickadj | |
756 | */ | |
757 | if (time_adjust > tickadj) | |
758 | time_adjust_step = tickadj; | |
759 | else if (time_adjust < -tickadj) | |
760 | time_adjust_step = -tickadj; | |
761 | ||
762 | /* Reduce by this step the amount of time left */ | |
763 | time_adjust -= time_adjust_step; | |
764 | } | |
765 | delta_nsec = tick_nsec + time_adjust_step * 1000; | |
766 | /* | |
767 | * Advance the phase, once it gets to one microsecond, then | |
768 | * advance the tick more. | |
769 | */ | |
770 | time_phase += time_adj; | |
771 | if (time_phase <= -FINENSEC) { | |
772 | long ltemp = -time_phase >> (SHIFT_SCALE - 10); | |
773 | time_phase += ltemp << (SHIFT_SCALE - 10); | |
774 | delta_nsec -= ltemp; | |
775 | } | |
776 | else if (time_phase >= FINENSEC) { | |
777 | long ltemp = time_phase >> (SHIFT_SCALE - 10); | |
778 | time_phase -= ltemp << (SHIFT_SCALE - 10); | |
779 | delta_nsec += ltemp; | |
780 | } | |
781 | xtime.tv_nsec += delta_nsec; | |
782 | time_interpolator_update(delta_nsec); | |
783 | ||
784 | /* Changes by adjtime() do not take effect till next tick. */ | |
785 | if (time_next_adjust != 0) { | |
786 | time_adjust = time_next_adjust; | |
787 | time_next_adjust = 0; | |
788 | } | |
789 | } | |
790 | ||
791 | /* | |
792 | * Using a loop looks inefficient, but "ticks" is | |
793 | * usually just one (we shouldn't be losing ticks, | |
794 | * we're doing this this way mainly for interrupt | |
795 | * latency reasons, not because we think we'll | |
796 | * have lots of lost timer ticks | |
797 | */ | |
798 | static void update_wall_time(unsigned long ticks) | |
799 | { | |
800 | do { | |
801 | ticks--; | |
802 | update_wall_time_one_tick(); | |
803 | if (xtime.tv_nsec >= 1000000000) { | |
804 | xtime.tv_nsec -= 1000000000; | |
805 | xtime.tv_sec++; | |
806 | second_overflow(); | |
807 | } | |
808 | } while (ticks); | |
809 | } | |
810 | ||
811 | /* | |
812 | * Called from the timer interrupt handler to charge one tick to the current | |
813 | * process. user_tick is 1 if the tick is user time, 0 for system. | |
814 | */ | |
815 | void update_process_times(int user_tick) | |
816 | { | |
817 | struct task_struct *p = current; | |
818 | int cpu = smp_processor_id(); | |
819 | ||
820 | /* Note: this timer irq context must be accounted for as well. */ | |
821 | if (user_tick) | |
822 | account_user_time(p, jiffies_to_cputime(1)); | |
823 | else | |
824 | account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1)); | |
825 | run_local_timers(); | |
826 | if (rcu_pending(cpu)) | |
827 | rcu_check_callbacks(cpu, user_tick); | |
828 | scheduler_tick(); | |
829 | run_posix_cpu_timers(p); | |
830 | } | |
831 | ||
832 | /* | |
833 | * Nr of active tasks - counted in fixed-point numbers | |
834 | */ | |
835 | static unsigned long count_active_tasks(void) | |
836 | { | |
837 | return (nr_running() + nr_uninterruptible()) * FIXED_1; | |
838 | } | |
839 | ||
840 | /* | |
841 | * Hmm.. Changed this, as the GNU make sources (load.c) seems to | |
842 | * imply that avenrun[] is the standard name for this kind of thing. | |
843 | * Nothing else seems to be standardized: the fractional size etc | |
844 | * all seem to differ on different machines. | |
845 | * | |
846 | * Requires xtime_lock to access. | |
847 | */ | |
848 | unsigned long avenrun[3]; | |
849 | ||
850 | EXPORT_SYMBOL(avenrun); | |
851 | ||
852 | /* | |
853 | * calc_load - given tick count, update the avenrun load estimates. | |
854 | * This is called while holding a write_lock on xtime_lock. | |
855 | */ | |
856 | static inline void calc_load(unsigned long ticks) | |
857 | { | |
858 | unsigned long active_tasks; /* fixed-point */ | |
859 | static int count = LOAD_FREQ; | |
860 | ||
861 | count -= ticks; | |
862 | if (count < 0) { | |
863 | count += LOAD_FREQ; | |
864 | active_tasks = count_active_tasks(); | |
865 | CALC_LOAD(avenrun[0], EXP_1, active_tasks); | |
866 | CALC_LOAD(avenrun[1], EXP_5, active_tasks); | |
867 | CALC_LOAD(avenrun[2], EXP_15, active_tasks); | |
868 | } | |
869 | } | |
870 | ||
871 | /* jiffies at the most recent update of wall time */ | |
872 | unsigned long wall_jiffies = INITIAL_JIFFIES; | |
873 | ||
874 | /* | |
875 | * This read-write spinlock protects us from races in SMP while | |
876 | * playing with xtime and avenrun. | |
877 | */ | |
878 | #ifndef ARCH_HAVE_XTIME_LOCK | |
879 | seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; | |
880 | ||
881 | EXPORT_SYMBOL(xtime_lock); | |
882 | #endif | |
883 | ||
884 | /* | |
885 | * This function runs timers and the timer-tq in bottom half context. | |
886 | */ | |
887 | static void run_timer_softirq(struct softirq_action *h) | |
888 | { | |
889 | tvec_base_t *base = &__get_cpu_var(tvec_bases); | |
890 | ||
891 | if (time_after_eq(jiffies, base->timer_jiffies)) | |
892 | __run_timers(base); | |
893 | } | |
894 | ||
895 | /* | |
896 | * Called by the local, per-CPU timer interrupt on SMP. | |
897 | */ | |
898 | void run_local_timers(void) | |
899 | { | |
900 | raise_softirq(TIMER_SOFTIRQ); | |
901 | } | |
902 | ||
903 | /* | |
904 | * Called by the timer interrupt. xtime_lock must already be taken | |
905 | * by the timer IRQ! | |
906 | */ | |
907 | static inline void update_times(void) | |
908 | { | |
909 | unsigned long ticks; | |
910 | ||
911 | ticks = jiffies - wall_jiffies; | |
912 | if (ticks) { | |
913 | wall_jiffies += ticks; | |
914 | update_wall_time(ticks); | |
915 | } | |
916 | calc_load(ticks); | |
917 | } | |
918 | ||
919 | /* | |
920 | * The 64-bit jiffies value is not atomic - you MUST NOT read it | |
921 | * without sampling the sequence number in xtime_lock. | |
922 | * jiffies is defined in the linker script... | |
923 | */ | |
924 | ||
925 | void do_timer(struct pt_regs *regs) | |
926 | { | |
927 | jiffies_64++; | |
928 | update_times(); | |
929 | } | |
930 | ||
931 | #ifdef __ARCH_WANT_SYS_ALARM | |
932 | ||
933 | /* | |
934 | * For backwards compatibility? This can be done in libc so Alpha | |
935 | * and all newer ports shouldn't need it. | |
936 | */ | |
937 | asmlinkage unsigned long sys_alarm(unsigned int seconds) | |
938 | { | |
939 | struct itimerval it_new, it_old; | |
940 | unsigned int oldalarm; | |
941 | ||
942 | it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; | |
943 | it_new.it_value.tv_sec = seconds; | |
944 | it_new.it_value.tv_usec = 0; | |
945 | do_setitimer(ITIMER_REAL, &it_new, &it_old); | |
946 | oldalarm = it_old.it_value.tv_sec; | |
947 | /* ehhh.. We can't return 0 if we have an alarm pending.. */ | |
948 | /* And we'd better return too much than too little anyway */ | |
949 | if ((!oldalarm && it_old.it_value.tv_usec) || it_old.it_value.tv_usec >= 500000) | |
950 | oldalarm++; | |
951 | return oldalarm; | |
952 | } | |
953 | ||
954 | #endif | |
955 | ||
956 | #ifndef __alpha__ | |
957 | ||
958 | /* | |
959 | * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this | |
960 | * should be moved into arch/i386 instead? | |
961 | */ | |
962 | ||
963 | /** | |
964 | * sys_getpid - return the thread group id of the current process | |
965 | * | |
966 | * Note, despite the name, this returns the tgid not the pid. The tgid and | |
967 | * the pid are identical unless CLONE_THREAD was specified on clone() in | |
968 | * which case the tgid is the same in all threads of the same group. | |
969 | * | |
970 | * This is SMP safe as current->tgid does not change. | |
971 | */ | |
972 | asmlinkage long sys_getpid(void) | |
973 | { | |
974 | return current->tgid; | |
975 | } | |
976 | ||
977 | /* | |
978 | * Accessing ->group_leader->real_parent is not SMP-safe, it could | |
979 | * change from under us. However, rather than getting any lock | |
980 | * we can use an optimistic algorithm: get the parent | |
981 | * pid, and go back and check that the parent is still | |
982 | * the same. If it has changed (which is extremely unlikely | |
983 | * indeed), we just try again.. | |
984 | * | |
985 | * NOTE! This depends on the fact that even if we _do_ | |
986 | * get an old value of "parent", we can happily dereference | |
987 | * the pointer (it was and remains a dereferencable kernel pointer | |
988 | * no matter what): we just can't necessarily trust the result | |
989 | * until we know that the parent pointer is valid. | |
990 | * | |
991 | * NOTE2: ->group_leader never changes from under us. | |
992 | */ | |
993 | asmlinkage long sys_getppid(void) | |
994 | { | |
995 | int pid; | |
996 | struct task_struct *me = current; | |
997 | struct task_struct *parent; | |
998 | ||
999 | parent = me->group_leader->real_parent; | |
1000 | for (;;) { | |
1001 | pid = parent->tgid; | |
1002 | #ifdef CONFIG_SMP | |
1003 | { | |
1004 | struct task_struct *old = parent; | |
1005 | ||
1006 | /* | |
1007 | * Make sure we read the pid before re-reading the | |
1008 | * parent pointer: | |
1009 | */ | |
1010 | rmb(); | |
1011 | parent = me->group_leader->real_parent; | |
1012 | if (old != parent) | |
1013 | continue; | |
1014 | } | |
1015 | #endif | |
1016 | break; | |
1017 | } | |
1018 | return pid; | |
1019 | } | |
1020 | ||
1021 | asmlinkage long sys_getuid(void) | |
1022 | { | |
1023 | /* Only we change this so SMP safe */ | |
1024 | return current->uid; | |
1025 | } | |
1026 | ||
1027 | asmlinkage long sys_geteuid(void) | |
1028 | { | |
1029 | /* Only we change this so SMP safe */ | |
1030 | return current->euid; | |
1031 | } | |
1032 | ||
1033 | asmlinkage long sys_getgid(void) | |
1034 | { | |
1035 | /* Only we change this so SMP safe */ | |
1036 | return current->gid; | |
1037 | } | |
1038 | ||
1039 | asmlinkage long sys_getegid(void) | |
1040 | { | |
1041 | /* Only we change this so SMP safe */ | |
1042 | return current->egid; | |
1043 | } | |
1044 | ||
1045 | #endif | |
1046 | ||
1047 | static void process_timeout(unsigned long __data) | |
1048 | { | |
1049 | wake_up_process((task_t *)__data); | |
1050 | } | |
1051 | ||
1052 | /** | |
1053 | * schedule_timeout - sleep until timeout | |
1054 | * @timeout: timeout value in jiffies | |
1055 | * | |
1056 | * Make the current task sleep until @timeout jiffies have | |
1057 | * elapsed. The routine will return immediately unless | |
1058 | * the current task state has been set (see set_current_state()). | |
1059 | * | |
1060 | * You can set the task state as follows - | |
1061 | * | |
1062 | * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to | |
1063 | * pass before the routine returns. The routine will return 0 | |
1064 | * | |
1065 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
1066 | * delivered to the current task. In this case the remaining time | |
1067 | * in jiffies will be returned, or 0 if the timer expired in time | |
1068 | * | |
1069 | * The current task state is guaranteed to be TASK_RUNNING when this | |
1070 | * routine returns. | |
1071 | * | |
1072 | * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule | |
1073 | * the CPU away without a bound on the timeout. In this case the return | |
1074 | * value will be %MAX_SCHEDULE_TIMEOUT. | |
1075 | * | |
1076 | * In all cases the return value is guaranteed to be non-negative. | |
1077 | */ | |
1078 | fastcall signed long __sched schedule_timeout(signed long timeout) | |
1079 | { | |
1080 | struct timer_list timer; | |
1081 | unsigned long expire; | |
1082 | ||
1083 | switch (timeout) | |
1084 | { | |
1085 | case MAX_SCHEDULE_TIMEOUT: | |
1086 | /* | |
1087 | * These two special cases are useful to be comfortable | |
1088 | * in the caller. Nothing more. We could take | |
1089 | * MAX_SCHEDULE_TIMEOUT from one of the negative value | |
1090 | * but I' d like to return a valid offset (>=0) to allow | |
1091 | * the caller to do everything it want with the retval. | |
1092 | */ | |
1093 | schedule(); | |
1094 | goto out; | |
1095 | default: | |
1096 | /* | |
1097 | * Another bit of PARANOID. Note that the retval will be | |
1098 | * 0 since no piece of kernel is supposed to do a check | |
1099 | * for a negative retval of schedule_timeout() (since it | |
1100 | * should never happens anyway). You just have the printk() | |
1101 | * that will tell you if something is gone wrong and where. | |
1102 | */ | |
1103 | if (timeout < 0) | |
1104 | { | |
1105 | printk(KERN_ERR "schedule_timeout: wrong timeout " | |
1106 | "value %lx from %p\n", timeout, | |
1107 | __builtin_return_address(0)); | |
1108 | current->state = TASK_RUNNING; | |
1109 | goto out; | |
1110 | } | |
1111 | } | |
1112 | ||
1113 | expire = timeout + jiffies; | |
1114 | ||
1115 | init_timer(&timer); | |
1116 | timer.expires = expire; | |
1117 | timer.data = (unsigned long) current; | |
1118 | timer.function = process_timeout; | |
1119 | ||
1120 | add_timer(&timer); | |
1121 | schedule(); | |
1122 | del_singleshot_timer_sync(&timer); | |
1123 | ||
1124 | timeout = expire - jiffies; | |
1125 | ||
1126 | out: | |
1127 | return timeout < 0 ? 0 : timeout; | |
1128 | } | |
1129 | ||
1130 | EXPORT_SYMBOL(schedule_timeout); | |
1131 | ||
1132 | /* Thread ID - the internal kernel "pid" */ | |
1133 | asmlinkage long sys_gettid(void) | |
1134 | { | |
1135 | return current->pid; | |
1136 | } | |
1137 | ||
1138 | static long __sched nanosleep_restart(struct restart_block *restart) | |
1139 | { | |
1140 | unsigned long expire = restart->arg0, now = jiffies; | |
1141 | struct timespec __user *rmtp = (struct timespec __user *) restart->arg1; | |
1142 | long ret; | |
1143 | ||
1144 | /* Did it expire while we handled signals? */ | |
1145 | if (!time_after(expire, now)) | |
1146 | return 0; | |
1147 | ||
1148 | current->state = TASK_INTERRUPTIBLE; | |
1149 | expire = schedule_timeout(expire - now); | |
1150 | ||
1151 | ret = 0; | |
1152 | if (expire) { | |
1153 | struct timespec t; | |
1154 | jiffies_to_timespec(expire, &t); | |
1155 | ||
1156 | ret = -ERESTART_RESTARTBLOCK; | |
1157 | if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) | |
1158 | ret = -EFAULT; | |
1159 | /* The 'restart' block is already filled in */ | |
1160 | } | |
1161 | return ret; | |
1162 | } | |
1163 | ||
1164 | asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) | |
1165 | { | |
1166 | struct timespec t; | |
1167 | unsigned long expire; | |
1168 | long ret; | |
1169 | ||
1170 | if (copy_from_user(&t, rqtp, sizeof(t))) | |
1171 | return -EFAULT; | |
1172 | ||
1173 | if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0)) | |
1174 | return -EINVAL; | |
1175 | ||
1176 | expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec); | |
1177 | current->state = TASK_INTERRUPTIBLE; | |
1178 | expire = schedule_timeout(expire); | |
1179 | ||
1180 | ret = 0; | |
1181 | if (expire) { | |
1182 | struct restart_block *restart; | |
1183 | jiffies_to_timespec(expire, &t); | |
1184 | if (rmtp && copy_to_user(rmtp, &t, sizeof(t))) | |
1185 | return -EFAULT; | |
1186 | ||
1187 | restart = ¤t_thread_info()->restart_block; | |
1188 | restart->fn = nanosleep_restart; | |
1189 | restart->arg0 = jiffies + expire; | |
1190 | restart->arg1 = (unsigned long) rmtp; | |
1191 | ret = -ERESTART_RESTARTBLOCK; | |
1192 | } | |
1193 | return ret; | |
1194 | } | |
1195 | ||
1196 | /* | |
1197 | * sys_sysinfo - fill in sysinfo struct | |
1198 | */ | |
1199 | asmlinkage long sys_sysinfo(struct sysinfo __user *info) | |
1200 | { | |
1201 | struct sysinfo val; | |
1202 | unsigned long mem_total, sav_total; | |
1203 | unsigned int mem_unit, bitcount; | |
1204 | unsigned long seq; | |
1205 | ||
1206 | memset((char *)&val, 0, sizeof(struct sysinfo)); | |
1207 | ||
1208 | do { | |
1209 | struct timespec tp; | |
1210 | seq = read_seqbegin(&xtime_lock); | |
1211 | ||
1212 | /* | |
1213 | * This is annoying. The below is the same thing | |
1214 | * posix_get_clock_monotonic() does, but it wants to | |
1215 | * take the lock which we want to cover the loads stuff | |
1216 | * too. | |
1217 | */ | |
1218 | ||
1219 | getnstimeofday(&tp); | |
1220 | tp.tv_sec += wall_to_monotonic.tv_sec; | |
1221 | tp.tv_nsec += wall_to_monotonic.tv_nsec; | |
1222 | if (tp.tv_nsec - NSEC_PER_SEC >= 0) { | |
1223 | tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC; | |
1224 | tp.tv_sec++; | |
1225 | } | |
1226 | val.uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); | |
1227 | ||
1228 | val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT); | |
1229 | val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT); | |
1230 | val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT); | |
1231 | ||
1232 | val.procs = nr_threads; | |
1233 | } while (read_seqretry(&xtime_lock, seq)); | |
1234 | ||
1235 | si_meminfo(&val); | |
1236 | si_swapinfo(&val); | |
1237 | ||
1238 | /* | |
1239 | * If the sum of all the available memory (i.e. ram + swap) | |
1240 | * is less than can be stored in a 32 bit unsigned long then | |
1241 | * we can be binary compatible with 2.2.x kernels. If not, | |
1242 | * well, in that case 2.2.x was broken anyways... | |
1243 | * | |
1244 | * -Erik Andersen <andersee@debian.org> | |
1245 | */ | |
1246 | ||
1247 | mem_total = val.totalram + val.totalswap; | |
1248 | if (mem_total < val.totalram || mem_total < val.totalswap) | |
1249 | goto out; | |
1250 | bitcount = 0; | |
1251 | mem_unit = val.mem_unit; | |
1252 | while (mem_unit > 1) { | |
1253 | bitcount++; | |
1254 | mem_unit >>= 1; | |
1255 | sav_total = mem_total; | |
1256 | mem_total <<= 1; | |
1257 | if (mem_total < sav_total) | |
1258 | goto out; | |
1259 | } | |
1260 | ||
1261 | /* | |
1262 | * If mem_total did not overflow, multiply all memory values by | |
1263 | * val.mem_unit and set it to 1. This leaves things compatible | |
1264 | * with 2.2.x, and also retains compatibility with earlier 2.4.x | |
1265 | * kernels... | |
1266 | */ | |
1267 | ||
1268 | val.mem_unit = 1; | |
1269 | val.totalram <<= bitcount; | |
1270 | val.freeram <<= bitcount; | |
1271 | val.sharedram <<= bitcount; | |
1272 | val.bufferram <<= bitcount; | |
1273 | val.totalswap <<= bitcount; | |
1274 | val.freeswap <<= bitcount; | |
1275 | val.totalhigh <<= bitcount; | |
1276 | val.freehigh <<= bitcount; | |
1277 | ||
1278 | out: | |
1279 | if (copy_to_user(info, &val, sizeof(struct sysinfo))) | |
1280 | return -EFAULT; | |
1281 | ||
1282 | return 0; | |
1283 | } | |
1284 | ||
1285 | static void __devinit init_timers_cpu(int cpu) | |
1286 | { | |
1287 | int j; | |
1288 | tvec_base_t *base; | |
1289 | ||
1290 | base = &per_cpu(tvec_bases, cpu); | |
1291 | spin_lock_init(&base->lock); | |
1292 | for (j = 0; j < TVN_SIZE; j++) { | |
1293 | INIT_LIST_HEAD(base->tv5.vec + j); | |
1294 | INIT_LIST_HEAD(base->tv4.vec + j); | |
1295 | INIT_LIST_HEAD(base->tv3.vec + j); | |
1296 | INIT_LIST_HEAD(base->tv2.vec + j); | |
1297 | } | |
1298 | for (j = 0; j < TVR_SIZE; j++) | |
1299 | INIT_LIST_HEAD(base->tv1.vec + j); | |
1300 | ||
1301 | base->timer_jiffies = jiffies; | |
1302 | } | |
1303 | ||
1304 | #ifdef CONFIG_HOTPLUG_CPU | |
1305 | static int migrate_timer_list(tvec_base_t *new_base, struct list_head *head) | |
1306 | { | |
1307 | struct timer_list *timer; | |
1308 | ||
1309 | while (!list_empty(head)) { | |
1310 | timer = list_entry(head->next, struct timer_list, entry); | |
1311 | /* We're locking backwards from __mod_timer order here, | |
1312 | beware deadlock. */ | |
1313 | if (!spin_trylock(&timer->lock)) | |
1314 | return 0; | |
1315 | list_del(&timer->entry); | |
1316 | internal_add_timer(new_base, timer); | |
1317 | timer->base = new_base; | |
1318 | spin_unlock(&timer->lock); | |
1319 | } | |
1320 | return 1; | |
1321 | } | |
1322 | ||
1323 | static void __devinit migrate_timers(int cpu) | |
1324 | { | |
1325 | tvec_base_t *old_base; | |
1326 | tvec_base_t *new_base; | |
1327 | int i; | |
1328 | ||
1329 | BUG_ON(cpu_online(cpu)); | |
1330 | old_base = &per_cpu(tvec_bases, cpu); | |
1331 | new_base = &get_cpu_var(tvec_bases); | |
1332 | ||
1333 | local_irq_disable(); | |
1334 | again: | |
1335 | /* Prevent deadlocks via ordering by old_base < new_base. */ | |
1336 | if (old_base < new_base) { | |
1337 | spin_lock(&new_base->lock); | |
1338 | spin_lock(&old_base->lock); | |
1339 | } else { | |
1340 | spin_lock(&old_base->lock); | |
1341 | spin_lock(&new_base->lock); | |
1342 | } | |
1343 | ||
1344 | if (old_base->running_timer) | |
1345 | BUG(); | |
1346 | for (i = 0; i < TVR_SIZE; i++) | |
1347 | if (!migrate_timer_list(new_base, old_base->tv1.vec + i)) | |
1348 | goto unlock_again; | |
1349 | for (i = 0; i < TVN_SIZE; i++) | |
1350 | if (!migrate_timer_list(new_base, old_base->tv2.vec + i) | |
1351 | || !migrate_timer_list(new_base, old_base->tv3.vec + i) | |
1352 | || !migrate_timer_list(new_base, old_base->tv4.vec + i) | |
1353 | || !migrate_timer_list(new_base, old_base->tv5.vec + i)) | |
1354 | goto unlock_again; | |
1355 | spin_unlock(&old_base->lock); | |
1356 | spin_unlock(&new_base->lock); | |
1357 | local_irq_enable(); | |
1358 | put_cpu_var(tvec_bases); | |
1359 | return; | |
1360 | ||
1361 | unlock_again: | |
1362 | /* Avoid deadlock with __mod_timer, by backing off. */ | |
1363 | spin_unlock(&old_base->lock); | |
1364 | spin_unlock(&new_base->lock); | |
1365 | cpu_relax(); | |
1366 | goto again; | |
1367 | } | |
1368 | #endif /* CONFIG_HOTPLUG_CPU */ | |
1369 | ||
1370 | static int __devinit timer_cpu_notify(struct notifier_block *self, | |
1371 | unsigned long action, void *hcpu) | |
1372 | { | |
1373 | long cpu = (long)hcpu; | |
1374 | switch(action) { | |
1375 | case CPU_UP_PREPARE: | |
1376 | init_timers_cpu(cpu); | |
1377 | break; | |
1378 | #ifdef CONFIG_HOTPLUG_CPU | |
1379 | case CPU_DEAD: | |
1380 | migrate_timers(cpu); | |
1381 | break; | |
1382 | #endif | |
1383 | default: | |
1384 | break; | |
1385 | } | |
1386 | return NOTIFY_OK; | |
1387 | } | |
1388 | ||
1389 | static struct notifier_block __devinitdata timers_nb = { | |
1390 | .notifier_call = timer_cpu_notify, | |
1391 | }; | |
1392 | ||
1393 | ||
1394 | void __init init_timers(void) | |
1395 | { | |
1396 | timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, | |
1397 | (void *)(long)smp_processor_id()); | |
1398 | register_cpu_notifier(&timers_nb); | |
1399 | open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); | |
1400 | } | |
1401 | ||
1402 | #ifdef CONFIG_TIME_INTERPOLATION | |
1403 | ||
1404 | struct time_interpolator *time_interpolator; | |
1405 | static struct time_interpolator *time_interpolator_list; | |
1406 | static DEFINE_SPINLOCK(time_interpolator_lock); | |
1407 | ||
1408 | static inline u64 time_interpolator_get_cycles(unsigned int src) | |
1409 | { | |
1410 | unsigned long (*x)(void); | |
1411 | ||
1412 | switch (src) | |
1413 | { | |
1414 | case TIME_SOURCE_FUNCTION: | |
1415 | x = time_interpolator->addr; | |
1416 | return x(); | |
1417 | ||
1418 | case TIME_SOURCE_MMIO64 : | |
1419 | return readq((void __iomem *) time_interpolator->addr); | |
1420 | ||
1421 | case TIME_SOURCE_MMIO32 : | |
1422 | return readl((void __iomem *) time_interpolator->addr); | |
1423 | ||
1424 | default: return get_cycles(); | |
1425 | } | |
1426 | } | |
1427 | ||
1428 | static inline u64 time_interpolator_get_counter(void) | |
1429 | { | |
1430 | unsigned int src = time_interpolator->source; | |
1431 | ||
1432 | if (time_interpolator->jitter) | |
1433 | { | |
1434 | u64 lcycle; | |
1435 | u64 now; | |
1436 | ||
1437 | do { | |
1438 | lcycle = time_interpolator->last_cycle; | |
1439 | now = time_interpolator_get_cycles(src); | |
1440 | if (lcycle && time_after(lcycle, now)) | |
1441 | return lcycle; | |
1442 | /* Keep track of the last timer value returned. The use of cmpxchg here | |
1443 | * will cause contention in an SMP environment. | |
1444 | */ | |
1445 | } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle)); | |
1446 | return now; | |
1447 | } | |
1448 | else | |
1449 | return time_interpolator_get_cycles(src); | |
1450 | } | |
1451 | ||
1452 | void time_interpolator_reset(void) | |
1453 | { | |
1454 | time_interpolator->offset = 0; | |
1455 | time_interpolator->last_counter = time_interpolator_get_counter(); | |
1456 | } | |
1457 | ||
1458 | #define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift) | |
1459 | ||
1460 | unsigned long time_interpolator_get_offset(void) | |
1461 | { | |
1462 | /* If we do not have a time interpolator set up then just return zero */ | |
1463 | if (!time_interpolator) | |
1464 | return 0; | |
1465 | ||
1466 | return time_interpolator->offset + | |
1467 | GET_TI_NSECS(time_interpolator_get_counter(), time_interpolator); | |
1468 | } | |
1469 | ||
1470 | #define INTERPOLATOR_ADJUST 65536 | |
1471 | #define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST | |
1472 | ||
1473 | static void time_interpolator_update(long delta_nsec) | |
1474 | { | |
1475 | u64 counter; | |
1476 | unsigned long offset; | |
1477 | ||
1478 | /* If there is no time interpolator set up then do nothing */ | |
1479 | if (!time_interpolator) | |
1480 | return; | |
1481 | ||
1482 | /* The interpolator compensates for late ticks by accumulating | |
1483 | * the late time in time_interpolator->offset. A tick earlier than | |
1484 | * expected will lead to a reset of the offset and a corresponding | |
1485 | * jump of the clock forward. Again this only works if the | |
1486 | * interpolator clock is running slightly slower than the regular clock | |
1487 | * and the tuning logic insures that. | |
1488 | */ | |
1489 | ||
1490 | counter = time_interpolator_get_counter(); | |
1491 | offset = time_interpolator->offset + GET_TI_NSECS(counter, time_interpolator); | |
1492 | ||
1493 | if (delta_nsec < 0 || (unsigned long) delta_nsec < offset) | |
1494 | time_interpolator->offset = offset - delta_nsec; | |
1495 | else { | |
1496 | time_interpolator->skips++; | |
1497 | time_interpolator->ns_skipped += delta_nsec - offset; | |
1498 | time_interpolator->offset = 0; | |
1499 | } | |
1500 | time_interpolator->last_counter = counter; | |
1501 | ||
1502 | /* Tuning logic for time interpolator invoked every minute or so. | |
1503 | * Decrease interpolator clock speed if no skips occurred and an offset is carried. | |
1504 | * Increase interpolator clock speed if we skip too much time. | |
1505 | */ | |
1506 | if (jiffies % INTERPOLATOR_ADJUST == 0) | |
1507 | { | |
1508 | if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC) | |
1509 | time_interpolator->nsec_per_cyc--; | |
1510 | if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0) | |
1511 | time_interpolator->nsec_per_cyc++; | |
1512 | time_interpolator->skips = 0; | |
1513 | time_interpolator->ns_skipped = 0; | |
1514 | } | |
1515 | } | |
1516 | ||
1517 | static inline int | |
1518 | is_better_time_interpolator(struct time_interpolator *new) | |
1519 | { | |
1520 | if (!time_interpolator) | |
1521 | return 1; | |
1522 | return new->frequency > 2*time_interpolator->frequency || | |
1523 | (unsigned long)new->drift < (unsigned long)time_interpolator->drift; | |
1524 | } | |
1525 | ||
1526 | void | |
1527 | register_time_interpolator(struct time_interpolator *ti) | |
1528 | { | |
1529 | unsigned long flags; | |
1530 | ||
1531 | /* Sanity check */ | |
1532 | if (ti->frequency == 0 || ti->mask == 0) | |
1533 | BUG(); | |
1534 | ||
1535 | ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency; | |
1536 | spin_lock(&time_interpolator_lock); | |
1537 | write_seqlock_irqsave(&xtime_lock, flags); | |
1538 | if (is_better_time_interpolator(ti)) { | |
1539 | time_interpolator = ti; | |
1540 | time_interpolator_reset(); | |
1541 | } | |
1542 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1543 | ||
1544 | ti->next = time_interpolator_list; | |
1545 | time_interpolator_list = ti; | |
1546 | spin_unlock(&time_interpolator_lock); | |
1547 | } | |
1548 | ||
1549 | void | |
1550 | unregister_time_interpolator(struct time_interpolator *ti) | |
1551 | { | |
1552 | struct time_interpolator *curr, **prev; | |
1553 | unsigned long flags; | |
1554 | ||
1555 | spin_lock(&time_interpolator_lock); | |
1556 | prev = &time_interpolator_list; | |
1557 | for (curr = *prev; curr; curr = curr->next) { | |
1558 | if (curr == ti) { | |
1559 | *prev = curr->next; | |
1560 | break; | |
1561 | } | |
1562 | prev = &curr->next; | |
1563 | } | |
1564 | ||
1565 | write_seqlock_irqsave(&xtime_lock, flags); | |
1566 | if (ti == time_interpolator) { | |
1567 | /* we lost the best time-interpolator: */ | |
1568 | time_interpolator = NULL; | |
1569 | /* find the next-best interpolator */ | |
1570 | for (curr = time_interpolator_list; curr; curr = curr->next) | |
1571 | if (is_better_time_interpolator(curr)) | |
1572 | time_interpolator = curr; | |
1573 | time_interpolator_reset(); | |
1574 | } | |
1575 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
1576 | spin_unlock(&time_interpolator_lock); | |
1577 | } | |
1578 | #endif /* CONFIG_TIME_INTERPOLATION */ | |
1579 | ||
1580 | /** | |
1581 | * msleep - sleep safely even with waitqueue interruptions | |
1582 | * @msecs: Time in milliseconds to sleep for | |
1583 | */ | |
1584 | void msleep(unsigned int msecs) | |
1585 | { | |
1586 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1587 | ||
1588 | while (timeout) { | |
1589 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1590 | timeout = schedule_timeout(timeout); | |
1591 | } | |
1592 | } | |
1593 | ||
1594 | EXPORT_SYMBOL(msleep); | |
1595 | ||
1596 | /** | |
1597 | * msleep_interruptible - sleep waiting for waitqueue interruptions | |
1598 | * @msecs: Time in milliseconds to sleep for | |
1599 | */ | |
1600 | unsigned long msleep_interruptible(unsigned int msecs) | |
1601 | { | |
1602 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1603 | ||
1604 | while (timeout && !signal_pending(current)) { | |
1605 | set_current_state(TASK_INTERRUPTIBLE); | |
1606 | timeout = schedule_timeout(timeout); | |
1607 | } | |
1608 | return jiffies_to_msecs(timeout); | |
1609 | } | |
1610 | ||
1611 | EXPORT_SYMBOL(msleep_interruptible); |