Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/kernel/timer.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 2 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 2 months ago) by niro
File MIME type: text/plain
File size: 42801 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | smp_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); |