[PATCH] sound/sparc/dbri: Use ARRAY_SIZE macro
[GitHub/MotorolaMobilityLLC/kernel-slsi.git] / kernel / timer.c
CommitLineData
1da177e4
LT
1/*
2 * linux/kernel/timer.c
3 *
4 * Kernel internal timers, kernel timekeeping, basic process system calls
5 *
6 * Copyright (C) 1991, 1992 Linus Torvalds
7 *
8 * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better.
9 *
10 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
11 * "A Kernel Model for Precision Timekeeping" by Dave Mills
12 * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
13 * serialize accesses to xtime/lost_ticks).
14 * Copyright (C) 1998 Andrea Arcangeli
15 * 1999-03-10 Improved NTP compatibility by Ulrich Windl
16 * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love
17 * 2000-10-05 Implemented scalable SMP per-CPU timer handling.
18 * Copyright (C) 2000, 2001, 2002 Ingo Molnar
19 * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
20 */
21
22#include <linux/kernel_stat.h>
23#include <linux/module.h>
24#include <linux/interrupt.h>
25#include <linux/percpu.h>
26#include <linux/init.h>
27#include <linux/mm.h>
28#include <linux/swap.h>
29#include <linux/notifier.h>
30#include <linux/thread_info.h>
31#include <linux/time.h>
32#include <linux/jiffies.h>
33#include <linux/posix-timers.h>
34#include <linux/cpu.h>
35#include <linux/syscalls.h>
97a41e26 36#include <linux/delay.h>
1da177e4
LT
37
38#include <asm/uaccess.h>
39#include <asm/unistd.h>
40#include <asm/div64.h>
41#include <asm/timex.h>
42#include <asm/io.h>
43
44#ifdef CONFIG_TIME_INTERPOLATION
45static void time_interpolator_update(long delta_nsec);
46#else
47#define time_interpolator_update(x)
48#endif
49
ecea8d19
TG
50u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
51
52EXPORT_SYMBOL(jiffies_64);
53
1da177e4
LT
54/*
55 * per-CPU timer vector definitions:
56 */
1da177e4
LT
57#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
58#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
59#define TVN_SIZE (1 << TVN_BITS)
60#define TVR_SIZE (1 << TVR_BITS)
61#define TVN_MASK (TVN_SIZE - 1)
62#define TVR_MASK (TVR_SIZE - 1)
63
64typedef struct tvec_s {
65 struct list_head vec[TVN_SIZE];
66} tvec_t;
67
68typedef struct tvec_root_s {
69 struct list_head vec[TVR_SIZE];
70} tvec_root_t;
71
72struct tvec_t_base_s {
3691c519
ON
73 spinlock_t lock;
74 struct timer_list *running_timer;
1da177e4 75 unsigned long timer_jiffies;
1da177e4
LT
76 tvec_root_t tv1;
77 tvec_t tv2;
78 tvec_t tv3;
79 tvec_t tv4;
80 tvec_t tv5;
81} ____cacheline_aligned_in_smp;
82
83typedef struct tvec_t_base_s tvec_base_t;
ba6edfcd 84
3691c519
ON
85tvec_base_t boot_tvec_bases;
86EXPORT_SYMBOL(boot_tvec_bases);
51d8c5ed 87static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = &boot_tvec_bases;
1da177e4
LT
88
89static inline void set_running_timer(tvec_base_t *base,
90 struct timer_list *timer)
91{
92#ifdef CONFIG_SMP
3691c519 93 base->running_timer = timer;
1da177e4
LT
94#endif
95}
96
1da177e4
LT
97static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
98{
99 unsigned long expires = timer->expires;
100 unsigned long idx = expires - base->timer_jiffies;
101 struct list_head *vec;
102
103 if (idx < TVR_SIZE) {
104 int i = expires & TVR_MASK;
105 vec = base->tv1.vec + i;
106 } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
107 int i = (expires >> TVR_BITS) & TVN_MASK;
108 vec = base->tv2.vec + i;
109 } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
110 int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
111 vec = base->tv3.vec + i;
112 } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
113 int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
114 vec = base->tv4.vec + i;
115 } else if ((signed long) idx < 0) {
116 /*
117 * Can happen if you add a timer with expires == jiffies,
118 * or you set a timer to go off in the past
119 */
120 vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
121 } else {
122 int i;
123 /* If the timeout is larger than 0xffffffff on 64-bit
124 * architectures then we use the maximum timeout:
125 */
126 if (idx > 0xffffffffUL) {
127 idx = 0xffffffffUL;
128 expires = idx + base->timer_jiffies;
129 }
130 i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
131 vec = base->tv5.vec + i;
132 }
133 /*
134 * Timers are FIFO:
135 */
136 list_add_tail(&timer->entry, vec);
137}
138
2aae4a10 139/**
55c888d6
ON
140 * init_timer - initialize a timer.
141 * @timer: the timer to be initialized
142 *
143 * init_timer() must be done to a timer prior calling *any* of the
144 * other timer functions.
145 */
146void fastcall init_timer(struct timer_list *timer)
147{
148 timer->entry.next = NULL;
bfe5d834 149 timer->base = __raw_get_cpu_var(tvec_bases);
55c888d6
ON
150}
151EXPORT_SYMBOL(init_timer);
152
153static inline void detach_timer(struct timer_list *timer,
154 int clear_pending)
155{
156 struct list_head *entry = &timer->entry;
157
158 __list_del(entry->prev, entry->next);
159 if (clear_pending)
160 entry->next = NULL;
161 entry->prev = LIST_POISON2;
162}
163
164/*
3691c519 165 * We are using hashed locking: holding per_cpu(tvec_bases).lock
55c888d6
ON
166 * means that all timers which are tied to this base via timer->base are
167 * locked, and the base itself is locked too.
168 *
169 * So __run_timers/migrate_timers can safely modify all timers which could
170 * be found on ->tvX lists.
171 *
172 * When the timer's base is locked, and the timer removed from list, it is
173 * possible to set timer->base = NULL and drop the lock: the timer remains
174 * locked.
175 */
3691c519 176static tvec_base_t *lock_timer_base(struct timer_list *timer,
55c888d6 177 unsigned long *flags)
89e7e374 178 __acquires(timer->base->lock)
55c888d6 179{
3691c519 180 tvec_base_t *base;
55c888d6
ON
181
182 for (;;) {
183 base = timer->base;
184 if (likely(base != NULL)) {
185 spin_lock_irqsave(&base->lock, *flags);
186 if (likely(base == timer->base))
187 return base;
188 /* The timer has migrated to another CPU */
189 spin_unlock_irqrestore(&base->lock, *flags);
190 }
191 cpu_relax();
192 }
193}
194
1da177e4
LT
195int __mod_timer(struct timer_list *timer, unsigned long expires)
196{
3691c519 197 tvec_base_t *base, *new_base;
1da177e4
LT
198 unsigned long flags;
199 int ret = 0;
200
201 BUG_ON(!timer->function);
1da177e4 202
55c888d6
ON
203 base = lock_timer_base(timer, &flags);
204
205 if (timer_pending(timer)) {
206 detach_timer(timer, 0);
207 ret = 1;
208 }
209
a4a6198b 210 new_base = __get_cpu_var(tvec_bases);
1da177e4 211
3691c519 212 if (base != new_base) {
1da177e4 213 /*
55c888d6
ON
214 * We are trying to schedule the timer on the local CPU.
215 * However we can't change timer's base while it is running,
216 * otherwise del_timer_sync() can't detect that the timer's
217 * handler yet has not finished. This also guarantees that
218 * the timer is serialized wrt itself.
1da177e4 219 */
a2c348fe 220 if (likely(base->running_timer != timer)) {
55c888d6
ON
221 /* See the comment in lock_timer_base() */
222 timer->base = NULL;
223 spin_unlock(&base->lock);
a2c348fe
ON
224 base = new_base;
225 spin_lock(&base->lock);
226 timer->base = base;
1da177e4
LT
227 }
228 }
229
1da177e4 230 timer->expires = expires;
a2c348fe
ON
231 internal_add_timer(base, timer);
232 spin_unlock_irqrestore(&base->lock, flags);
1da177e4
LT
233
234 return ret;
235}
236
237EXPORT_SYMBOL(__mod_timer);
238
2aae4a10 239/**
1da177e4
LT
240 * add_timer_on - start a timer on a particular CPU
241 * @timer: the timer to be added
242 * @cpu: the CPU to start it on
243 *
244 * This is not very scalable on SMP. Double adds are not possible.
245 */
246void add_timer_on(struct timer_list *timer, int cpu)
247{
a4a6198b 248 tvec_base_t *base = per_cpu(tvec_bases, cpu);
1da177e4 249 unsigned long flags;
55c888d6 250
1da177e4 251 BUG_ON(timer_pending(timer) || !timer->function);
3691c519
ON
252 spin_lock_irqsave(&base->lock, flags);
253 timer->base = base;
1da177e4 254 internal_add_timer(base, timer);
3691c519 255 spin_unlock_irqrestore(&base->lock, flags);
1da177e4
LT
256}
257
258
2aae4a10 259/**
1da177e4
LT
260 * mod_timer - modify a timer's timeout
261 * @timer: the timer to be modified
2aae4a10 262 * @expires: new timeout in jiffies
1da177e4
LT
263 *
264 * mod_timer is a more efficient way to update the expire field of an
265 * active timer (if the timer is inactive it will be activated)
266 *
267 * mod_timer(timer, expires) is equivalent to:
268 *
269 * del_timer(timer); timer->expires = expires; add_timer(timer);
270 *
271 * Note that if there are multiple unserialized concurrent users of the
272 * same timer, then mod_timer() is the only safe way to modify the timeout,
273 * since add_timer() cannot modify an already running timer.
274 *
275 * The function returns whether it has modified a pending timer or not.
276 * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
277 * active timer returns 1.)
278 */
279int mod_timer(struct timer_list *timer, unsigned long expires)
280{
281 BUG_ON(!timer->function);
282
1da177e4
LT
283 /*
284 * This is a common optimization triggered by the
285 * networking code - if the timer is re-modified
286 * to be the same thing then just return:
287 */
288 if (timer->expires == expires && timer_pending(timer))
289 return 1;
290
291 return __mod_timer(timer, expires);
292}
293
294EXPORT_SYMBOL(mod_timer);
295
2aae4a10 296/**
1da177e4
LT
297 * del_timer - deactive a timer.
298 * @timer: the timer to be deactivated
299 *
300 * del_timer() deactivates a timer - this works on both active and inactive
301 * timers.
302 *
303 * The function returns whether it has deactivated a pending timer or not.
304 * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
305 * active timer returns 1.)
306 */
307int del_timer(struct timer_list *timer)
308{
3691c519 309 tvec_base_t *base;
1da177e4 310 unsigned long flags;
55c888d6 311 int ret = 0;
1da177e4 312
55c888d6
ON
313 if (timer_pending(timer)) {
314 base = lock_timer_base(timer, &flags);
315 if (timer_pending(timer)) {
316 detach_timer(timer, 1);
317 ret = 1;
318 }
1da177e4 319 spin_unlock_irqrestore(&base->lock, flags);
1da177e4 320 }
1da177e4 321
55c888d6 322 return ret;
1da177e4
LT
323}
324
325EXPORT_SYMBOL(del_timer);
326
327#ifdef CONFIG_SMP
2aae4a10
REB
328/**
329 * try_to_del_timer_sync - Try to deactivate a timer
330 * @timer: timer do del
331 *
fd450b73
ON
332 * This function tries to deactivate a timer. Upon successful (ret >= 0)
333 * exit the timer is not queued and the handler is not running on any CPU.
334 *
335 * It must not be called from interrupt contexts.
336 */
337int try_to_del_timer_sync(struct timer_list *timer)
338{
3691c519 339 tvec_base_t *base;
fd450b73
ON
340 unsigned long flags;
341 int ret = -1;
342
343 base = lock_timer_base(timer, &flags);
344
345 if (base->running_timer == timer)
346 goto out;
347
348 ret = 0;
349 if (timer_pending(timer)) {
350 detach_timer(timer, 1);
351 ret = 1;
352 }
353out:
354 spin_unlock_irqrestore(&base->lock, flags);
355
356 return ret;
357}
358
2aae4a10 359/**
1da177e4
LT
360 * del_timer_sync - deactivate a timer and wait for the handler to finish.
361 * @timer: the timer to be deactivated
362 *
363 * This function only differs from del_timer() on SMP: besides deactivating
364 * the timer it also makes sure the handler has finished executing on other
365 * CPUs.
366 *
367 * Synchronization rules: callers must prevent restarting of the timer,
368 * otherwise this function is meaningless. It must not be called from
369 * interrupt contexts. The caller must not hold locks which would prevent
55c888d6
ON
370 * completion of the timer's handler. The timer's handler must not call
371 * add_timer_on(). Upon exit the timer is not queued and the handler is
372 * not running on any CPU.
1da177e4
LT
373 *
374 * The function returns whether it has deactivated a pending timer or not.
1da177e4
LT
375 */
376int del_timer_sync(struct timer_list *timer)
377{
fd450b73
ON
378 for (;;) {
379 int ret = try_to_del_timer_sync(timer);
380 if (ret >= 0)
381 return ret;
a0009652 382 cpu_relax();
fd450b73 383 }
1da177e4 384}
1da177e4 385
55c888d6 386EXPORT_SYMBOL(del_timer_sync);
1da177e4
LT
387#endif
388
389static int cascade(tvec_base_t *base, tvec_t *tv, int index)
390{
391 /* cascade all the timers from tv up one level */
3439dd86
P
392 struct timer_list *timer, *tmp;
393 struct list_head tv_list;
394
395 list_replace_init(tv->vec + index, &tv_list);
1da177e4 396
1da177e4 397 /*
3439dd86
P
398 * We are removing _all_ timers from the list, so we
399 * don't have to detach them individually.
1da177e4 400 */
3439dd86
P
401 list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
402 BUG_ON(timer->base != base);
403 internal_add_timer(base, timer);
1da177e4 404 }
1da177e4
LT
405
406 return index;
407}
408
2aae4a10
REB
409#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
410
411/**
1da177e4
LT
412 * __run_timers - run all expired timers (if any) on this CPU.
413 * @base: the timer vector to be processed.
414 *
415 * This function cascades all vectors and executes all expired timer
416 * vectors.
417 */
1da177e4
LT
418static inline void __run_timers(tvec_base_t *base)
419{
420 struct timer_list *timer;
421
3691c519 422 spin_lock_irq(&base->lock);
1da177e4 423 while (time_after_eq(jiffies, base->timer_jiffies)) {
626ab0e6 424 struct list_head work_list;
1da177e4
LT
425 struct list_head *head = &work_list;
426 int index = base->timer_jiffies & TVR_MASK;
626ab0e6 427
1da177e4
LT
428 /*
429 * Cascade timers:
430 */
431 if (!index &&
432 (!cascade(base, &base->tv2, INDEX(0))) &&
433 (!cascade(base, &base->tv3, INDEX(1))) &&
434 !cascade(base, &base->tv4, INDEX(2)))
435 cascade(base, &base->tv5, INDEX(3));
626ab0e6
ON
436 ++base->timer_jiffies;
437 list_replace_init(base->tv1.vec + index, &work_list);
55c888d6 438 while (!list_empty(head)) {
1da177e4
LT
439 void (*fn)(unsigned long);
440 unsigned long data;
441
442 timer = list_entry(head->next,struct timer_list,entry);
443 fn = timer->function;
444 data = timer->data;
445
1da177e4 446 set_running_timer(base, timer);
55c888d6 447 detach_timer(timer, 1);
3691c519 448 spin_unlock_irq(&base->lock);
1da177e4 449 {
be5b4fbd 450 int preempt_count = preempt_count();
1da177e4
LT
451 fn(data);
452 if (preempt_count != preempt_count()) {
be5b4fbd
JJ
453 printk(KERN_WARNING "huh, entered %p "
454 "with preempt_count %08x, exited"
455 " with %08x?\n",
456 fn, preempt_count,
457 preempt_count());
1da177e4
LT
458 BUG();
459 }
460 }
3691c519 461 spin_lock_irq(&base->lock);
1da177e4
LT
462 }
463 }
464 set_running_timer(base, NULL);
3691c519 465 spin_unlock_irq(&base->lock);
1da177e4
LT
466}
467
468#ifdef CONFIG_NO_IDLE_HZ
469/*
470 * Find out when the next timer event is due to happen. This
471 * is used on S/390 to stop all activity when a cpus is idle.
472 * This functions needs to be called disabled.
473 */
474unsigned long next_timer_interrupt(void)
475{
476 tvec_base_t *base;
477 struct list_head *list;
478 struct timer_list *nte;
479 unsigned long expires;
69239749
TL
480 unsigned long hr_expires = MAX_JIFFY_OFFSET;
481 ktime_t hr_delta;
1da177e4
LT
482 tvec_t *varray[4];
483 int i, j;
484
69239749
TL
485 hr_delta = hrtimer_get_next_event();
486 if (hr_delta.tv64 != KTIME_MAX) {
487 struct timespec tsdelta;
488 tsdelta = ktime_to_timespec(hr_delta);
489 hr_expires = timespec_to_jiffies(&tsdelta);
490 if (hr_expires < 3)
491 return hr_expires + jiffies;
492 }
493 hr_expires += jiffies;
494
a4a6198b 495 base = __get_cpu_var(tvec_bases);
3691c519 496 spin_lock(&base->lock);
1da177e4 497 expires = base->timer_jiffies + (LONG_MAX >> 1);
53f087fe 498 list = NULL;
1da177e4
LT
499
500 /* Look for timer events in tv1. */
501 j = base->timer_jiffies & TVR_MASK;
502 do {
503 list_for_each_entry(nte, base->tv1.vec + j, entry) {
504 expires = nte->expires;
505 if (j < (base->timer_jiffies & TVR_MASK))
506 list = base->tv2.vec + (INDEX(0));
507 goto found;
508 }
509 j = (j + 1) & TVR_MASK;
510 } while (j != (base->timer_jiffies & TVR_MASK));
511
512 /* Check tv2-tv5. */
513 varray[0] = &base->tv2;
514 varray[1] = &base->tv3;
515 varray[2] = &base->tv4;
516 varray[3] = &base->tv5;
517 for (i = 0; i < 4; i++) {
518 j = INDEX(i);
519 do {
520 if (list_empty(varray[i]->vec + j)) {
521 j = (j + 1) & TVN_MASK;
522 continue;
523 }
524 list_for_each_entry(nte, varray[i]->vec + j, entry)
525 if (time_before(nte->expires, expires))
526 expires = nte->expires;
527 if (j < (INDEX(i)) && i < 3)
528 list = varray[i + 1]->vec + (INDEX(i + 1));
529 goto found;
530 } while (j != (INDEX(i)));
531 }
532found:
533 if (list) {
534 /*
535 * The search wrapped. We need to look at the next list
536 * from next tv element that would cascade into tv element
537 * where we found the timer element.
538 */
539 list_for_each_entry(nte, list, entry) {
540 if (time_before(nte->expires, expires))
541 expires = nte->expires;
542 }
543 }
3691c519 544 spin_unlock(&base->lock);
69239749 545
0662b713
ZA
546 /*
547 * It can happen that other CPUs service timer IRQs and increment
548 * jiffies, but we have not yet got a local timer tick to process
549 * the timer wheels. In that case, the expiry time can be before
550 * jiffies, but since the high-resolution timer here is relative to
551 * jiffies, the default expression when high-resolution timers are
552 * not active,
553 *
554 * time_before(MAX_JIFFY_OFFSET + jiffies, expires)
555 *
556 * would falsely evaluate to true. If that is the case, just
557 * return jiffies so that we can immediately fire the local timer
558 */
559 if (time_before(expires, jiffies))
560 return jiffies;
561
69239749
TL
562 if (time_before(hr_expires, expires))
563 return hr_expires;
564
1da177e4
LT
565 return expires;
566}
567#endif
568
569/******************************************************************/
570
571/*
572 * Timekeeping variables
573 */
574unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
575unsigned long tick_nsec = TICK_NSEC; /* ACTHZ period (nsec) */
576
577/*
578 * The current time
579 * wall_to_monotonic is what we need to add to xtime (or xtime corrected
580 * for sub jiffie times) to get to monotonic time. Monotonic is pegged
581 * at zero at system boot time, so wall_to_monotonic will be negative,
582 * however, we will ALWAYS keep the tv_nsec part positive so we can use
583 * the usual normalization.
584 */
585struct timespec xtime __attribute__ ((aligned (16)));
586struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
587
588EXPORT_SYMBOL(xtime);
589
590/* Don't completely fail for HZ > 500. */
591int tickadj = 500/HZ ? : 1; /* microsecs */
592
593
594/*
595 * phase-lock loop variables
596 */
597/* TIME_ERROR prevents overwriting the CMOS clock */
598int time_state = TIME_OK; /* clock synchronization status */
599int time_status = STA_UNSYNC; /* clock status bits */
600long time_offset; /* time adjustment (us) */
601long time_constant = 2; /* pll time constant */
602long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
603long time_precision = 1; /* clock precision (us) */
604long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
605long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
1da177e4
LT
606long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
607 /* frequency offset (scaled ppm)*/
608static long time_adj; /* tick adjust (scaled 1 / HZ) */
609long time_reftime; /* time at last adjustment (s) */
610long time_adjust;
611long time_next_adjust;
612
613/*
614 * this routine handles the overflow of the microsecond field
615 *
616 * The tricky bits of code to handle the accurate clock support
617 * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
618 * They were originally developed for SUN and DEC kernels.
619 * All the kudos should go to Dave for this stuff.
620 *
621 */
622static void second_overflow(void)
623{
a5a0d52c
AM
624 long ltemp;
625
626 /* Bump the maxerror field */
627 time_maxerror += time_tolerance >> SHIFT_USEC;
628 if (time_maxerror > NTP_PHASE_LIMIT) {
629 time_maxerror = NTP_PHASE_LIMIT;
630 time_status |= STA_UNSYNC;
1da177e4 631 }
a5a0d52c
AM
632
633 /*
634 * Leap second processing. If in leap-insert state at the end of the
635 * day, the system clock is set back one second; if in leap-delete
636 * state, the system clock is set ahead one second. The microtime()
637 * routine or external clock driver will insure that reported time is
638 * always monotonic. The ugly divides should be replaced.
639 */
640 switch (time_state) {
641 case TIME_OK:
642 if (time_status & STA_INS)
643 time_state = TIME_INS;
644 else if (time_status & STA_DEL)
645 time_state = TIME_DEL;
646 break;
647 case TIME_INS:
648 if (xtime.tv_sec % 86400 == 0) {
649 xtime.tv_sec--;
650 wall_to_monotonic.tv_sec++;
651 /*
652 * The timer interpolator will make time change
653 * gradually instead of an immediate jump by one second
654 */
655 time_interpolator_update(-NSEC_PER_SEC);
656 time_state = TIME_OOP;
657 clock_was_set();
658 printk(KERN_NOTICE "Clock: inserting leap second "
659 "23:59:60 UTC\n");
660 }
661 break;
662 case TIME_DEL:
663 if ((xtime.tv_sec + 1) % 86400 == 0) {
664 xtime.tv_sec++;
665 wall_to_monotonic.tv_sec--;
666 /*
667 * Use of time interpolator for a gradual change of
668 * time
669 */
670 time_interpolator_update(NSEC_PER_SEC);
671 time_state = TIME_WAIT;
672 clock_was_set();
673 printk(KERN_NOTICE "Clock: deleting leap second "
674 "23:59:59 UTC\n");
675 }
676 break;
677 case TIME_OOP:
678 time_state = TIME_WAIT;
679 break;
680 case TIME_WAIT:
681 if (!(time_status & (STA_INS | STA_DEL)))
682 time_state = TIME_OK;
1da177e4 683 }
a5a0d52c
AM
684
685 /*
686 * Compute the phase adjustment for the next second. In PLL mode, the
687 * offset is reduced by a fixed factor times the time constant. In FLL
688 * mode the offset is used directly. In either mode, the maximum phase
689 * adjustment for each second is clamped so as to spread the adjustment
690 * over not more than the number of seconds between updates.
691 */
1da177e4
LT
692 ltemp = time_offset;
693 if (!(time_status & STA_FLL))
1bb34a41 694 ltemp = shift_right(ltemp, SHIFT_KG + time_constant);
695 ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE);
696 ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE);
1da177e4
LT
697 time_offset -= ltemp;
698 time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
1da177e4 699
a5a0d52c
AM
700 /*
701 * Compute the frequency estimate and additional phase adjustment due
5ddcfa87 702 * to frequency error for the next second.
a5a0d52c 703 */
5ddcfa87 704 ltemp = time_freq;
a5a0d52c 705 time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
1da177e4
LT
706
707#if HZ == 100
a5a0d52c
AM
708 /*
709 * Compensate for (HZ==100) != (1 << SHIFT_HZ). Add 25% and 3.125% to
710 * get 128.125; => only 0.125% error (p. 14)
711 */
712 time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5);
1da177e4 713#endif
4b8f573b 714#if HZ == 250
a5a0d52c
AM
715 /*
716 * Compensate for (HZ==250) != (1 << SHIFT_HZ). Add 1.5625% and
717 * 0.78125% to get 255.85938; => only 0.05% error (p. 14)
718 */
719 time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
4b8f573b 720#endif
1da177e4 721#if HZ == 1000
a5a0d52c
AM
722 /*
723 * Compensate for (HZ==1000) != (1 << SHIFT_HZ). Add 1.5625% and
724 * 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
725 */
726 time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
1da177e4
LT
727#endif
728}
729
726c14bf
PM
730/*
731 * Returns how many microseconds we need to add to xtime this tick
732 * in doing an adjustment requested with adjtime.
733 */
734static long adjtime_adjustment(void)
1da177e4 735{
726c14bf 736 long time_adjust_step;
1da177e4 737
726c14bf
PM
738 time_adjust_step = time_adjust;
739 if (time_adjust_step) {
a5a0d52c
AM
740 /*
741 * We are doing an adjtime thing. Prepare time_adjust_step to
742 * be within bounds. Note that a positive time_adjust means we
743 * want the clock to run faster.
744 *
745 * Limit the amount of the step to be in the range
746 * -tickadj .. +tickadj
747 */
748 time_adjust_step = min(time_adjust_step, (long)tickadj);
749 time_adjust_step = max(time_adjust_step, (long)-tickadj);
726c14bf
PM
750 }
751 return time_adjust_step;
752}
a5a0d52c 753
726c14bf 754/* in the NTP reference this is called "hardclock()" */
5eb6d205 755static void update_ntp_one_tick(void)
726c14bf 756{
5eb6d205 757 long time_adjust_step;
726c14bf
PM
758
759 time_adjust_step = adjtime_adjustment();
760 if (time_adjust_step)
a5a0d52c
AM
761 /* Reduce by this step the amount of time left */
762 time_adjust -= time_adjust_step;
1da177e4
LT
763
764 /* Changes by adjtime() do not take effect till next tick. */
765 if (time_next_adjust != 0) {
766 time_adjust = time_next_adjust;
767 time_next_adjust = 0;
768 }
769}
770
726c14bf
PM
771/*
772 * Return how long ticks are at the moment, that is, how much time
773 * update_wall_time_one_tick will add to xtime next time we call it
774 * (assuming no calls to do_adjtimex in the meantime).
260a4230 775 * The return value is in fixed-point nanoseconds shifted by the
776 * specified number of bits to the right of the binary point.
726c14bf
PM
777 * This function has no side-effects.
778 */
19923c19 779u64 current_tick_length(void)
726c14bf
PM
780{
781 long delta_nsec;
260a4230 782 u64 ret;
726c14bf 783
260a4230 784 /* calculate the finest interval NTP will allow.
785 * ie: nanosecond value shifted by (SHIFT_SCALE - 10)
786 */
726c14bf 787 delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
19923c19
RZ
788 ret = (u64)delta_nsec << TICK_LENGTH_SHIFT;
789 ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10));
260a4230 790
791 return ret;
726c14bf
PM
792}
793
ad596171 794/* XXX - all of this timekeeping code should be later moved to time.c */
795#include <linux/clocksource.h>
796static struct clocksource *clock; /* pointer to current clocksource */
cf3c769b 797
798#ifdef CONFIG_GENERIC_TIME
799/**
800 * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
801 *
802 * private function, must hold xtime_lock lock when being
803 * called. Returns the number of nanoseconds since the
804 * last call to update_wall_time() (adjusted by NTP scaling)
805 */
806static inline s64 __get_nsec_offset(void)
807{
808 cycle_t cycle_now, cycle_delta;
809 s64 ns_offset;
810
811 /* read clocksource: */
a2752549 812 cycle_now = clocksource_read(clock);
cf3c769b 813
814 /* calculate the delta since the last update_wall_time: */
19923c19 815 cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
cf3c769b 816
817 /* convert to nanoseconds: */
818 ns_offset = cyc2ns(clock, cycle_delta);
819
820 return ns_offset;
821}
822
823/**
824 * __get_realtime_clock_ts - Returns the time of day in a timespec
825 * @ts: pointer to the timespec to be set
826 *
827 * Returns the time of day in a timespec. Used by
828 * do_gettimeofday() and get_realtime_clock_ts().
829 */
830static inline void __get_realtime_clock_ts(struct timespec *ts)
831{
832 unsigned long seq;
833 s64 nsecs;
834
835 do {
836 seq = read_seqbegin(&xtime_lock);
837
838 *ts = xtime;
839 nsecs = __get_nsec_offset();
840
841 } while (read_seqretry(&xtime_lock, seq));
842
843 timespec_add_ns(ts, nsecs);
844}
845
846/**
a2752549 847 * getnstimeofday - Returns the time of day in a timespec
cf3c769b 848 * @ts: pointer to the timespec to be set
849 *
850 * Returns the time of day in a timespec.
851 */
852void getnstimeofday(struct timespec *ts)
853{
854 __get_realtime_clock_ts(ts);
855}
856
857EXPORT_SYMBOL(getnstimeofday);
858
859/**
860 * do_gettimeofday - Returns the time of day in a timeval
861 * @tv: pointer to the timeval to be set
862 *
863 * NOTE: Users should be converted to using get_realtime_clock_ts()
864 */
865void do_gettimeofday(struct timeval *tv)
866{
867 struct timespec now;
868
869 __get_realtime_clock_ts(&now);
870 tv->tv_sec = now.tv_sec;
871 tv->tv_usec = now.tv_nsec/1000;
872}
873
874EXPORT_SYMBOL(do_gettimeofday);
875/**
876 * do_settimeofday - Sets the time of day
877 * @tv: pointer to the timespec variable containing the new time
878 *
879 * Sets the time of day to the new time and update NTP and notify hrtimers
880 */
881int do_settimeofday(struct timespec *tv)
882{
883 unsigned long flags;
884 time_t wtm_sec, sec = tv->tv_sec;
885 long wtm_nsec, nsec = tv->tv_nsec;
886
887 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
888 return -EINVAL;
889
890 write_seqlock_irqsave(&xtime_lock, flags);
891
892 nsec -= __get_nsec_offset();
893
894 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
895 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
896
897 set_normalized_timespec(&xtime, sec, nsec);
898 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
899
e154ff3d 900 clock->error = 0;
cf3c769b 901 ntp_clear();
902
903 write_sequnlock_irqrestore(&xtime_lock, flags);
904
905 /* signal hrtimers about time change */
906 clock_was_set();
907
908 return 0;
909}
910
911EXPORT_SYMBOL(do_settimeofday);
912
913/**
914 * change_clocksource - Swaps clocksources if a new one is available
915 *
916 * Accumulates current time interval and initializes new clocksource
917 */
918static int change_clocksource(void)
919{
920 struct clocksource *new;
921 cycle_t now;
922 u64 nsec;
a2752549 923 new = clocksource_get_next();
cf3c769b 924 if (clock != new) {
a2752549 925 now = clocksource_read(new);
cf3c769b 926 nsec = __get_nsec_offset();
927 timespec_add_ns(&xtime, nsec);
928
929 clock = new;
19923c19 930 clock->cycle_last = now;
cf3c769b 931 printk(KERN_INFO "Time: %s clocksource has been installed.\n",
932 clock->name);
933 return 1;
934 } else if (clock->update_callback) {
935 return clock->update_callback();
936 }
937 return 0;
938}
939#else
940#define change_clocksource() (0)
941#endif
942
943/**
944 * timeofday_is_continuous - check to see if timekeeping is free running
945 */
946int timekeeping_is_continuous(void)
947{
948 unsigned long seq;
949 int ret;
950
951 do {
952 seq = read_seqbegin(&xtime_lock);
953
954 ret = clock->is_continuous;
955
956 } while (read_seqretry(&xtime_lock, seq));
957
958 return ret;
959}
960
1da177e4 961/*
ad596171 962 * timekeeping_init - Initializes the clocksource and common timekeeping values
1da177e4 963 */
ad596171 964void __init timekeeping_init(void)
1da177e4 965{
ad596171 966 unsigned long flags;
967
968 write_seqlock_irqsave(&xtime_lock, flags);
a2752549 969 clock = clocksource_get_next();
970 clocksource_calculate_interval(clock, tick_nsec);
19923c19 971 clock->cycle_last = clocksource_read(clock);
ad596171 972 ntp_clear();
973 write_sequnlock_irqrestore(&xtime_lock, flags);
974}
975
976
3e143475 977static int timekeeping_suspended;
2aae4a10 978/**
ad596171 979 * timekeeping_resume - Resumes the generic timekeeping subsystem.
980 * @dev: unused
981 *
982 * This is for the generic clocksource timekeeping.
983 * xtime/wall_to_monotonic/jiffies/wall_jiffies/etc are
984 * still managed by arch specific suspend/resume code.
985 */
986static int timekeeping_resume(struct sys_device *dev)
987{
988 unsigned long flags;
989
990 write_seqlock_irqsave(&xtime_lock, flags);
991 /* restart the last cycle value */
19923c19 992 clock->cycle_last = clocksource_read(clock);
3e143475 993 clock->error = 0;
994 timekeeping_suspended = 0;
995 write_sequnlock_irqrestore(&xtime_lock, flags);
996 return 0;
997}
998
999static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
1000{
1001 unsigned long flags;
1002
1003 write_seqlock_irqsave(&xtime_lock, flags);
1004 timekeeping_suspended = 1;
ad596171 1005 write_sequnlock_irqrestore(&xtime_lock, flags);
1006 return 0;
1007}
1008
1009/* sysfs resume/suspend bits for timekeeping */
1010static struct sysdev_class timekeeping_sysclass = {
1011 .resume = timekeeping_resume,
3e143475 1012 .suspend = timekeeping_suspend,
ad596171 1013 set_kset_name("timekeeping"),
1014};
1015
1016static struct sys_device device_timer = {
1017 .id = 0,
1018 .cls = &timekeeping_sysclass,
1019};
1020
1021static int __init timekeeping_init_device(void)
1022{
1023 int error = sysdev_class_register(&timekeeping_sysclass);
1024 if (!error)
1025 error = sysdev_register(&device_timer);
1026 return error;
1027}
1028
1029device_initcall(timekeeping_init_device);
1030
19923c19 1031/*
e154ff3d 1032 * If the error is already larger, we look ahead even further
19923c19
RZ
1033 * to compensate for late or lost adjustments.
1034 */
e154ff3d 1035static __always_inline int clocksource_bigadjust(s64 error, s64 *interval, s64 *offset)
19923c19 1036{
e154ff3d
RZ
1037 s64 tick_error, i;
1038 u32 look_ahead, adj;
1039 s32 error2, mult;
19923c19
RZ
1040
1041 /*
e154ff3d
RZ
1042 * Use the current error value to determine how much to look ahead.
1043 * The larger the error the slower we adjust for it to avoid problems
1044 * with losing too many ticks, otherwise we would overadjust and
1045 * produce an even larger error. The smaller the adjustment the
1046 * faster we try to adjust for it, as lost ticks can do less harm
1047 * here. This is tuned so that an error of about 1 msec is adusted
1048 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
19923c19 1049 */
e154ff3d
RZ
1050 error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
1051 error2 = abs(error2);
1052 for (look_ahead = 0; error2 > 0; look_ahead++)
1053 error2 >>= 2;
19923c19
RZ
1054
1055 /*
e154ff3d
RZ
1056 * Now calculate the error in (1 << look_ahead) ticks, but first
1057 * remove the single look ahead already included in the error.
19923c19 1058 */
e154ff3d
RZ
1059 tick_error = current_tick_length() >> (TICK_LENGTH_SHIFT - clock->shift + 1);
1060 tick_error -= clock->xtime_interval >> 1;
1061 error = ((error - tick_error) >> look_ahead) + tick_error;
1062
1063 /* Finally calculate the adjustment shift value. */
1064 i = *interval;
1065 mult = 1;
1066 if (error < 0) {
1067 error = -error;
1068 *interval = -*interval;
1069 *offset = -*offset;
1070 mult = -1;
19923c19 1071 }
e154ff3d
RZ
1072 for (adj = 0; error > i; adj++)
1073 error >>= 1;
19923c19
RZ
1074
1075 *interval <<= adj;
1076 *offset <<= adj;
e154ff3d 1077 return mult << adj;
19923c19
RZ
1078}
1079
1080/*
1081 * Adjust the multiplier to reduce the error value,
1082 * this is optimized for the most common adjustments of -1,0,1,
1083 * for other values we can do a bit more work.
1084 */
1085static void clocksource_adjust(struct clocksource *clock, s64 offset)
1086{
1087 s64 error, interval = clock->cycle_interval;
1088 int adj;
1089
1090 error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
1091 if (error > interval) {
e154ff3d
RZ
1092 error >>= 2;
1093 if (likely(error <= interval))
1094 adj = 1;
1095 else
1096 adj = clocksource_bigadjust(error, &interval, &offset);
19923c19 1097 } else if (error < -interval) {
e154ff3d
RZ
1098 error >>= 2;
1099 if (likely(error >= -interval)) {
1100 adj = -1;
1101 interval = -interval;
1102 offset = -offset;
1103 } else
1104 adj = clocksource_bigadjust(error, &interval, &offset);
19923c19
RZ
1105 } else
1106 return;
1107
1108 clock->mult += adj;
1109 clock->xtime_interval += interval;
1110 clock->xtime_nsec -= offset;
1111 clock->error -= (interval - offset) << (TICK_LENGTH_SHIFT - clock->shift);
1112}
1113
2aae4a10 1114/**
ad596171 1115 * update_wall_time - Uses the current clocksource to increment the wall time
1116 *
1117 * Called from the timer interrupt, must hold a write on xtime_lock.
1118 */
1119static void update_wall_time(void)
1120{
19923c19 1121 cycle_t offset;
ad596171 1122
3e143475 1123 /* Make sure we're fully resumed: */
1124 if (unlikely(timekeeping_suspended))
1125 return;
5eb6d205 1126
19923c19
RZ
1127#ifdef CONFIG_GENERIC_TIME
1128 offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
1129#else
1130 offset = clock->cycle_interval;
1131#endif
3e143475 1132 clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
ad596171 1133
1134 /* normally this loop will run just once, however in the
1135 * case of lost or late ticks, it will accumulate correctly.
1136 */
19923c19 1137 while (offset >= clock->cycle_interval) {
ad596171 1138 /* accumulate one interval */
19923c19
RZ
1139 clock->xtime_nsec += clock->xtime_interval;
1140 clock->cycle_last += clock->cycle_interval;
1141 offset -= clock->cycle_interval;
1142
1143 if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
1144 clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
1145 xtime.tv_sec++;
1146 second_overflow();
1147 }
ad596171 1148
5eb6d205 1149 /* interpolator bits */
19923c19 1150 time_interpolator_update(clock->xtime_interval
5eb6d205 1151 >> clock->shift);
1152 /* increment the NTP state machine */
1153 update_ntp_one_tick();
1154
1155 /* accumulate error between NTP and clock interval */
19923c19
RZ
1156 clock->error += current_tick_length();
1157 clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
1158 }
5eb6d205 1159
19923c19
RZ
1160 /* correct the clock when NTP error is too big */
1161 clocksource_adjust(clock, offset);
5eb6d205 1162
5eb6d205 1163 /* store full nanoseconds into xtime */
e154ff3d 1164 xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
19923c19 1165 clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
cf3c769b 1166
1167 /* check to see if there is a new clocksource to use */
1168 if (change_clocksource()) {
19923c19
RZ
1169 clock->error = 0;
1170 clock->xtime_nsec = 0;
a2752549 1171 clocksource_calculate_interval(clock, tick_nsec);
cf3c769b 1172 }
1da177e4
LT
1173}
1174
1175/*
1176 * Called from the timer interrupt handler to charge one tick to the current
1177 * process. user_tick is 1 if the tick is user time, 0 for system.
1178 */
1179void update_process_times(int user_tick)
1180{
1181 struct task_struct *p = current;
1182 int cpu = smp_processor_id();
1183
1184 /* Note: this timer irq context must be accounted for as well. */
1185 if (user_tick)
1186 account_user_time(p, jiffies_to_cputime(1));
1187 else
1188 account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1));
1189 run_local_timers();
1190 if (rcu_pending(cpu))
1191 rcu_check_callbacks(cpu, user_tick);
1192 scheduler_tick();
1193 run_posix_cpu_timers(p);
1194}
1195
1196/*
1197 * Nr of active tasks - counted in fixed-point numbers
1198 */
1199static unsigned long count_active_tasks(void)
1200{
db1b1fef 1201 return nr_active() * FIXED_1;
1da177e4
LT
1202}
1203
1204/*
1205 * Hmm.. Changed this, as the GNU make sources (load.c) seems to
1206 * imply that avenrun[] is the standard name for this kind of thing.
1207 * Nothing else seems to be standardized: the fractional size etc
1208 * all seem to differ on different machines.
1209 *
1210 * Requires xtime_lock to access.
1211 */
1212unsigned long avenrun[3];
1213
1214EXPORT_SYMBOL(avenrun);
1215
1216/*
1217 * calc_load - given tick count, update the avenrun load estimates.
1218 * This is called while holding a write_lock on xtime_lock.
1219 */
1220static inline void calc_load(unsigned long ticks)
1221{
1222 unsigned long active_tasks; /* fixed-point */
1223 static int count = LOAD_FREQ;
1224
1225 count -= ticks;
1226 if (count < 0) {
1227 count += LOAD_FREQ;
1228 active_tasks = count_active_tasks();
1229 CALC_LOAD(avenrun[0], EXP_1, active_tasks);
1230 CALC_LOAD(avenrun[1], EXP_5, active_tasks);
1231 CALC_LOAD(avenrun[2], EXP_15, active_tasks);
1232 }
1233}
1234
1235/* jiffies at the most recent update of wall time */
1236unsigned long wall_jiffies = INITIAL_JIFFIES;
1237
1238/*
1239 * This read-write spinlock protects us from races in SMP while
1240 * playing with xtime and avenrun.
1241 */
1242#ifndef ARCH_HAVE_XTIME_LOCK
e4d91918 1243__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
1da177e4
LT
1244
1245EXPORT_SYMBOL(xtime_lock);
1246#endif
1247
1248/*
1249 * This function runs timers and the timer-tq in bottom half context.
1250 */
1251static void run_timer_softirq(struct softirq_action *h)
1252{
a4a6198b 1253 tvec_base_t *base = __get_cpu_var(tvec_bases);
1da177e4 1254
c0a31329 1255 hrtimer_run_queues();
1da177e4
LT
1256 if (time_after_eq(jiffies, base->timer_jiffies))
1257 __run_timers(base);
1258}
1259
1260/*
1261 * Called by the local, per-CPU timer interrupt on SMP.
1262 */
1263void run_local_timers(void)
1264{
1265 raise_softirq(TIMER_SOFTIRQ);
6687a97d 1266 softlockup_tick();
1da177e4
LT
1267}
1268
1269/*
1270 * Called by the timer interrupt. xtime_lock must already be taken
1271 * by the timer IRQ!
1272 */
1273static inline void update_times(void)
1274{
1275 unsigned long ticks;
1276
1277 ticks = jiffies - wall_jiffies;
ad596171 1278 wall_jiffies += ticks;
1279 update_wall_time();
1da177e4
LT
1280 calc_load(ticks);
1281}
1282
1283/*
1284 * The 64-bit jiffies value is not atomic - you MUST NOT read it
1285 * without sampling the sequence number in xtime_lock.
1286 * jiffies is defined in the linker script...
1287 */
1288
1289void do_timer(struct pt_regs *regs)
1290{
1291 jiffies_64++;
5aee405c
AN
1292 /* prevent loading jiffies before storing new jiffies_64 value. */
1293 barrier();
1da177e4
LT
1294 update_times();
1295}
1296
1297#ifdef __ARCH_WANT_SYS_ALARM
1298
1299/*
1300 * For backwards compatibility? This can be done in libc so Alpha
1301 * and all newer ports shouldn't need it.
1302 */
1303asmlinkage unsigned long sys_alarm(unsigned int seconds)
1304{
c08b8a49 1305 return alarm_setitimer(seconds);
1da177e4
LT
1306}
1307
1308#endif
1309
1310#ifndef __alpha__
1311
1312/*
1313 * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
1314 * should be moved into arch/i386 instead?
1315 */
1316
1317/**
1318 * sys_getpid - return the thread group id of the current process
1319 *
1320 * Note, despite the name, this returns the tgid not the pid. The tgid and
1321 * the pid are identical unless CLONE_THREAD was specified on clone() in
1322 * which case the tgid is the same in all threads of the same group.
1323 *
1324 * This is SMP safe as current->tgid does not change.
1325 */
1326asmlinkage long sys_getpid(void)
1327{
1328 return current->tgid;
1329}
1330
1331/*
6997a6fa
KK
1332 * Accessing ->real_parent is not SMP-safe, it could
1333 * change from under us. However, we can use a stale
1334 * value of ->real_parent under rcu_read_lock(), see
1335 * release_task()->call_rcu(delayed_put_task_struct).
1da177e4
LT
1336 */
1337asmlinkage long sys_getppid(void)
1338{
1339 int pid;
1da177e4 1340
6997a6fa
KK
1341 rcu_read_lock();
1342 pid = rcu_dereference(current->real_parent)->tgid;
1343 rcu_read_unlock();
1da177e4 1344
1da177e4
LT
1345 return pid;
1346}
1347
1348asmlinkage long sys_getuid(void)
1349{
1350 /* Only we change this so SMP safe */
1351 return current->uid;
1352}
1353
1354asmlinkage long sys_geteuid(void)
1355{
1356 /* Only we change this so SMP safe */
1357 return current->euid;
1358}
1359
1360asmlinkage long sys_getgid(void)
1361{
1362 /* Only we change this so SMP safe */
1363 return current->gid;
1364}
1365
1366asmlinkage long sys_getegid(void)
1367{
1368 /* Only we change this so SMP safe */
1369 return current->egid;
1370}
1371
1372#endif
1373
1374static void process_timeout(unsigned long __data)
1375{
36c8b586 1376 wake_up_process((struct task_struct *)__data);
1da177e4
LT
1377}
1378
1379/**
1380 * schedule_timeout - sleep until timeout
1381 * @timeout: timeout value in jiffies
1382 *
1383 * Make the current task sleep until @timeout jiffies have
1384 * elapsed. The routine will return immediately unless
1385 * the current task state has been set (see set_current_state()).
1386 *
1387 * You can set the task state as follows -
1388 *
1389 * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
1390 * pass before the routine returns. The routine will return 0
1391 *
1392 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1393 * delivered to the current task. In this case the remaining time
1394 * in jiffies will be returned, or 0 if the timer expired in time
1395 *
1396 * The current task state is guaranteed to be TASK_RUNNING when this
1397 * routine returns.
1398 *
1399 * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
1400 * the CPU away without a bound on the timeout. In this case the return
1401 * value will be %MAX_SCHEDULE_TIMEOUT.
1402 *
1403 * In all cases the return value is guaranteed to be non-negative.
1404 */
1405fastcall signed long __sched schedule_timeout(signed long timeout)
1406{
1407 struct timer_list timer;
1408 unsigned long expire;
1409
1410 switch (timeout)
1411 {
1412 case MAX_SCHEDULE_TIMEOUT:
1413 /*
1414 * These two special cases are useful to be comfortable
1415 * in the caller. Nothing more. We could take
1416 * MAX_SCHEDULE_TIMEOUT from one of the negative value
1417 * but I' d like to return a valid offset (>=0) to allow
1418 * the caller to do everything it want with the retval.
1419 */
1420 schedule();
1421 goto out;
1422 default:
1423 /*
1424 * Another bit of PARANOID. Note that the retval will be
1425 * 0 since no piece of kernel is supposed to do a check
1426 * for a negative retval of schedule_timeout() (since it
1427 * should never happens anyway). You just have the printk()
1428 * that will tell you if something is gone wrong and where.
1429 */
1430 if (timeout < 0)
1431 {
1432 printk(KERN_ERR "schedule_timeout: wrong timeout "
a5a0d52c
AM
1433 "value %lx from %p\n", timeout,
1434 __builtin_return_address(0));
1da177e4
LT
1435 current->state = TASK_RUNNING;
1436 goto out;
1437 }
1438 }
1439
1440 expire = timeout + jiffies;
1441
a8db2db1
ON
1442 setup_timer(&timer, process_timeout, (unsigned long)current);
1443 __mod_timer(&timer, expire);
1da177e4
LT
1444 schedule();
1445 del_singleshot_timer_sync(&timer);
1446
1447 timeout = expire - jiffies;
1448
1449 out:
1450 return timeout < 0 ? 0 : timeout;
1451}
1da177e4
LT
1452EXPORT_SYMBOL(schedule_timeout);
1453
8a1c1757
AM
1454/*
1455 * We can use __set_current_state() here because schedule_timeout() calls
1456 * schedule() unconditionally.
1457 */
64ed93a2
NA
1458signed long __sched schedule_timeout_interruptible(signed long timeout)
1459{
a5a0d52c
AM
1460 __set_current_state(TASK_INTERRUPTIBLE);
1461 return schedule_timeout(timeout);
64ed93a2
NA
1462}
1463EXPORT_SYMBOL(schedule_timeout_interruptible);
1464
1465signed long __sched schedule_timeout_uninterruptible(signed long timeout)
1466{
a5a0d52c
AM
1467 __set_current_state(TASK_UNINTERRUPTIBLE);
1468 return schedule_timeout(timeout);
64ed93a2
NA
1469}
1470EXPORT_SYMBOL(schedule_timeout_uninterruptible);
1471
1da177e4
LT
1472/* Thread ID - the internal kernel "pid" */
1473asmlinkage long sys_gettid(void)
1474{
1475 return current->pid;
1476}
1477
2aae4a10 1478/**
1da177e4 1479 * sys_sysinfo - fill in sysinfo struct
2aae4a10 1480 * @info: pointer to buffer to fill
1da177e4
LT
1481 */
1482asmlinkage long sys_sysinfo(struct sysinfo __user *info)
1483{
1484 struct sysinfo val;
1485 unsigned long mem_total, sav_total;
1486 unsigned int mem_unit, bitcount;
1487 unsigned long seq;
1488
1489 memset((char *)&val, 0, sizeof(struct sysinfo));
1490
1491 do {
1492 struct timespec tp;
1493 seq = read_seqbegin(&xtime_lock);
1494
1495 /*
1496 * This is annoying. The below is the same thing
1497 * posix_get_clock_monotonic() does, but it wants to
1498 * take the lock which we want to cover the loads stuff
1499 * too.
1500 */
1501
1502 getnstimeofday(&tp);
1503 tp.tv_sec += wall_to_monotonic.tv_sec;
1504 tp.tv_nsec += wall_to_monotonic.tv_nsec;
1505 if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
1506 tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC;
1507 tp.tv_sec++;
1508 }
1509 val.uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
1510
1511 val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
1512 val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
1513 val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
1514
1515 val.procs = nr_threads;
1516 } while (read_seqretry(&xtime_lock, seq));
1517
1518 si_meminfo(&val);
1519 si_swapinfo(&val);
1520
1521 /*
1522 * If the sum of all the available memory (i.e. ram + swap)
1523 * is less than can be stored in a 32 bit unsigned long then
1524 * we can be binary compatible with 2.2.x kernels. If not,
1525 * well, in that case 2.2.x was broken anyways...
1526 *
1527 * -Erik Andersen <andersee@debian.org>
1528 */
1529
1530 mem_total = val.totalram + val.totalswap;
1531 if (mem_total < val.totalram || mem_total < val.totalswap)
1532 goto out;
1533 bitcount = 0;
1534 mem_unit = val.mem_unit;
1535 while (mem_unit > 1) {
1536 bitcount++;
1537 mem_unit >>= 1;
1538 sav_total = mem_total;
1539 mem_total <<= 1;
1540 if (mem_total < sav_total)
1541 goto out;
1542 }
1543
1544 /*
1545 * If mem_total did not overflow, multiply all memory values by
1546 * val.mem_unit and set it to 1. This leaves things compatible
1547 * with 2.2.x, and also retains compatibility with earlier 2.4.x
1548 * kernels...
1549 */
1550
1551 val.mem_unit = 1;
1552 val.totalram <<= bitcount;
1553 val.freeram <<= bitcount;
1554 val.sharedram <<= bitcount;
1555 val.bufferram <<= bitcount;
1556 val.totalswap <<= bitcount;
1557 val.freeswap <<= bitcount;
1558 val.totalhigh <<= bitcount;
1559 val.freehigh <<= bitcount;
1560
1561 out:
1562 if (copy_to_user(info, &val, sizeof(struct sysinfo)))
1563 return -EFAULT;
1564
1565 return 0;
1566}
1567
d730e882
IM
1568/*
1569 * lockdep: we want to track each per-CPU base as a separate lock-class,
1570 * but timer-bases are kmalloc()-ed, so we need to attach separate
1571 * keys to them:
1572 */
1573static struct lock_class_key base_lock_keys[NR_CPUS];
1574
a4a6198b 1575static int __devinit init_timers_cpu(int cpu)
1da177e4
LT
1576{
1577 int j;
1578 tvec_base_t *base;
ba6edfcd 1579 static char __devinitdata tvec_base_done[NR_CPUS];
55c888d6 1580
ba6edfcd 1581 if (!tvec_base_done[cpu]) {
a4a6198b
JB
1582 static char boot_done;
1583
a4a6198b 1584 if (boot_done) {
ba6edfcd
AM
1585 /*
1586 * The APs use this path later in boot
1587 */
a4a6198b
JB
1588 base = kmalloc_node(sizeof(*base), GFP_KERNEL,
1589 cpu_to_node(cpu));
1590 if (!base)
1591 return -ENOMEM;
1592 memset(base, 0, sizeof(*base));
ba6edfcd 1593 per_cpu(tvec_bases, cpu) = base;
a4a6198b 1594 } else {
ba6edfcd
AM
1595 /*
1596 * This is for the boot CPU - we use compile-time
1597 * static initialisation because per-cpu memory isn't
1598 * ready yet and because the memory allocators are not
1599 * initialised either.
1600 */
a4a6198b 1601 boot_done = 1;
ba6edfcd 1602 base = &boot_tvec_bases;
a4a6198b 1603 }
ba6edfcd
AM
1604 tvec_base_done[cpu] = 1;
1605 } else {
1606 base = per_cpu(tvec_bases, cpu);
a4a6198b 1607 }
ba6edfcd 1608
3691c519 1609 spin_lock_init(&base->lock);
d730e882
IM
1610 lockdep_set_class(&base->lock, base_lock_keys + cpu);
1611
1da177e4
LT
1612 for (j = 0; j < TVN_SIZE; j++) {
1613 INIT_LIST_HEAD(base->tv5.vec + j);
1614 INIT_LIST_HEAD(base->tv4.vec + j);
1615 INIT_LIST_HEAD(base->tv3.vec + j);
1616 INIT_LIST_HEAD(base->tv2.vec + j);
1617 }
1618 for (j = 0; j < TVR_SIZE; j++)
1619 INIT_LIST_HEAD(base->tv1.vec + j);
1620
1621 base->timer_jiffies = jiffies;
a4a6198b 1622 return 0;
1da177e4
LT
1623}
1624
1625#ifdef CONFIG_HOTPLUG_CPU
55c888d6 1626static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head)
1da177e4
LT
1627{
1628 struct timer_list *timer;
1629
1630 while (!list_empty(head)) {
1631 timer = list_entry(head->next, struct timer_list, entry);
55c888d6 1632 detach_timer(timer, 0);
3691c519 1633 timer->base = new_base;
1da177e4 1634 internal_add_timer(new_base, timer);
1da177e4 1635 }
1da177e4
LT
1636}
1637
1638static void __devinit migrate_timers(int cpu)
1639{
1640 tvec_base_t *old_base;
1641 tvec_base_t *new_base;
1642 int i;
1643
1644 BUG_ON(cpu_online(cpu));
a4a6198b
JB
1645 old_base = per_cpu(tvec_bases, cpu);
1646 new_base = get_cpu_var(tvec_bases);
1da177e4
LT
1647
1648 local_irq_disable();
3691c519
ON
1649 spin_lock(&new_base->lock);
1650 spin_lock(&old_base->lock);
1651
1652 BUG_ON(old_base->running_timer);
1da177e4 1653
1da177e4 1654 for (i = 0; i < TVR_SIZE; i++)
55c888d6
ON
1655 migrate_timer_list(new_base, old_base->tv1.vec + i);
1656 for (i = 0; i < TVN_SIZE; i++) {
1657 migrate_timer_list(new_base, old_base->tv2.vec + i);
1658 migrate_timer_list(new_base, old_base->tv3.vec + i);
1659 migrate_timer_list(new_base, old_base->tv4.vec + i);
1660 migrate_timer_list(new_base, old_base->tv5.vec + i);
1661 }
1662
3691c519
ON
1663 spin_unlock(&old_base->lock);
1664 spin_unlock(&new_base->lock);
1da177e4
LT
1665 local_irq_enable();
1666 put_cpu_var(tvec_bases);
1da177e4
LT
1667}
1668#endif /* CONFIG_HOTPLUG_CPU */
1669
8c78f307 1670static int __cpuinit timer_cpu_notify(struct notifier_block *self,
1da177e4
LT
1671 unsigned long action, void *hcpu)
1672{
1673 long cpu = (long)hcpu;
1674 switch(action) {
1675 case CPU_UP_PREPARE:
a4a6198b
JB
1676 if (init_timers_cpu(cpu) < 0)
1677 return NOTIFY_BAD;
1da177e4
LT
1678 break;
1679#ifdef CONFIG_HOTPLUG_CPU
1680 case CPU_DEAD:
1681 migrate_timers(cpu);
1682 break;
1683#endif
1684 default:
1685 break;
1686 }
1687 return NOTIFY_OK;
1688}
1689
8c78f307 1690static struct notifier_block __cpuinitdata timers_nb = {
1da177e4
LT
1691 .notifier_call = timer_cpu_notify,
1692};
1693
1694
1695void __init init_timers(void)
1696{
1697 timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1698 (void *)(long)smp_processor_id());
1699 register_cpu_notifier(&timers_nb);
1700 open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
1701}
1702
1703#ifdef CONFIG_TIME_INTERPOLATION
1704
67890d70
CL
1705struct time_interpolator *time_interpolator __read_mostly;
1706static struct time_interpolator *time_interpolator_list __read_mostly;
1da177e4
LT
1707static DEFINE_SPINLOCK(time_interpolator_lock);
1708
1709static inline u64 time_interpolator_get_cycles(unsigned int src)
1710{
1711 unsigned long (*x)(void);
1712
1713 switch (src)
1714 {
1715 case TIME_SOURCE_FUNCTION:
1716 x = time_interpolator->addr;
1717 return x();
1718
1719 case TIME_SOURCE_MMIO64 :
685db65e 1720 return readq_relaxed((void __iomem *)time_interpolator->addr);
1da177e4
LT
1721
1722 case TIME_SOURCE_MMIO32 :
685db65e 1723 return readl_relaxed((void __iomem *)time_interpolator->addr);
1da177e4
LT
1724
1725 default: return get_cycles();
1726 }
1727}
1728
486d46ae 1729static inline u64 time_interpolator_get_counter(int writelock)
1da177e4
LT
1730{
1731 unsigned int src = time_interpolator->source;
1732
1733 if (time_interpolator->jitter)
1734 {
1735 u64 lcycle;
1736 u64 now;
1737
1738 do {
1739 lcycle = time_interpolator->last_cycle;
1740 now = time_interpolator_get_cycles(src);
1741 if (lcycle && time_after(lcycle, now))
1742 return lcycle;
486d46ae
AW
1743
1744 /* When holding the xtime write lock, there's no need
1745 * to add the overhead of the cmpxchg. Readers are
1746 * force to retry until the write lock is released.
1747 */
1748 if (writelock) {
1749 time_interpolator->last_cycle = now;
1750 return now;
1751 }
1da177e4
LT
1752 /* Keep track of the last timer value returned. The use of cmpxchg here
1753 * will cause contention in an SMP environment.
1754 */
1755 } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
1756 return now;
1757 }
1758 else
1759 return time_interpolator_get_cycles(src);
1760}
1761
1762void time_interpolator_reset(void)
1763{
1764 time_interpolator->offset = 0;
486d46ae 1765 time_interpolator->last_counter = time_interpolator_get_counter(1);
1da177e4
LT
1766}
1767
1768#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
1769
1770unsigned long time_interpolator_get_offset(void)
1771{
1772 /* If we do not have a time interpolator set up then just return zero */
1773 if (!time_interpolator)
1774 return 0;
1775
1776 return time_interpolator->offset +
486d46ae 1777 GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
1da177e4
LT
1778}
1779
1780#define INTERPOLATOR_ADJUST 65536
1781#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
1782
1783static void time_interpolator_update(long delta_nsec)
1784{
1785 u64 counter;
1786 unsigned long offset;
1787
1788 /* If there is no time interpolator set up then do nothing */
1789 if (!time_interpolator)
1790 return;
1791
a5a0d52c
AM
1792 /*
1793 * The interpolator compensates for late ticks by accumulating the late
1794 * time in time_interpolator->offset. A tick earlier than expected will
1795 * lead to a reset of the offset and a corresponding jump of the clock
1796 * forward. Again this only works if the interpolator clock is running
1797 * slightly slower than the regular clock and the tuning logic insures
1798 * that.
1799 */
1da177e4 1800
486d46ae 1801 counter = time_interpolator_get_counter(1);
a5a0d52c
AM
1802 offset = time_interpolator->offset +
1803 GET_TI_NSECS(counter, time_interpolator);
1da177e4
LT
1804
1805 if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
1806 time_interpolator->offset = offset - delta_nsec;
1807 else {
1808 time_interpolator->skips++;
1809 time_interpolator->ns_skipped += delta_nsec - offset;
1810 time_interpolator->offset = 0;
1811 }
1812 time_interpolator->last_counter = counter;
1813
1814 /* Tuning logic for time interpolator invoked every minute or so.
1815 * Decrease interpolator clock speed if no skips occurred and an offset is carried.
1816 * Increase interpolator clock speed if we skip too much time.
1817 */
1818 if (jiffies % INTERPOLATOR_ADJUST == 0)
1819 {
b20367a6 1820 if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
1da177e4
LT
1821 time_interpolator->nsec_per_cyc--;
1822 if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
1823 time_interpolator->nsec_per_cyc++;
1824 time_interpolator->skips = 0;
1825 time_interpolator->ns_skipped = 0;
1826 }
1827}
1828
1829static inline int
1830is_better_time_interpolator(struct time_interpolator *new)
1831{
1832 if (!time_interpolator)
1833 return 1;
1834 return new->frequency > 2*time_interpolator->frequency ||
1835 (unsigned long)new->drift < (unsigned long)time_interpolator->drift;
1836}
1837
1838void
1839register_time_interpolator(struct time_interpolator *ti)
1840{
1841 unsigned long flags;
1842
1843 /* Sanity check */
9f31252c 1844 BUG_ON(ti->frequency == 0 || ti->mask == 0);
1da177e4
LT
1845
1846 ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
1847 spin_lock(&time_interpolator_lock);
1848 write_seqlock_irqsave(&xtime_lock, flags);
1849 if (is_better_time_interpolator(ti)) {
1850 time_interpolator = ti;
1851 time_interpolator_reset();
1852 }
1853 write_sequnlock_irqrestore(&xtime_lock, flags);
1854
1855 ti->next = time_interpolator_list;
1856 time_interpolator_list = ti;
1857 spin_unlock(&time_interpolator_lock);
1858}
1859
1860void
1861unregister_time_interpolator(struct time_interpolator *ti)
1862{
1863 struct time_interpolator *curr, **prev;
1864 unsigned long flags;
1865
1866 spin_lock(&time_interpolator_lock);
1867 prev = &time_interpolator_list;
1868 for (curr = *prev; curr; curr = curr->next) {
1869 if (curr == ti) {
1870 *prev = curr->next;
1871 break;
1872 }
1873 prev = &curr->next;
1874 }
1875
1876 write_seqlock_irqsave(&xtime_lock, flags);
1877 if (ti == time_interpolator) {
1878 /* we lost the best time-interpolator: */
1879 time_interpolator = NULL;
1880 /* find the next-best interpolator */
1881 for (curr = time_interpolator_list; curr; curr = curr->next)
1882 if (is_better_time_interpolator(curr))
1883 time_interpolator = curr;
1884 time_interpolator_reset();
1885 }
1886 write_sequnlock_irqrestore(&xtime_lock, flags);
1887 spin_unlock(&time_interpolator_lock);
1888}
1889#endif /* CONFIG_TIME_INTERPOLATION */
1890
1891/**
1892 * msleep - sleep safely even with waitqueue interruptions
1893 * @msecs: Time in milliseconds to sleep for
1894 */
1895void msleep(unsigned int msecs)
1896{
1897 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1898
75bcc8c5
NA
1899 while (timeout)
1900 timeout = schedule_timeout_uninterruptible(timeout);
1da177e4
LT
1901}
1902
1903EXPORT_SYMBOL(msleep);
1904
1905/**
96ec3efd 1906 * msleep_interruptible - sleep waiting for signals
1da177e4
LT
1907 * @msecs: Time in milliseconds to sleep for
1908 */
1909unsigned long msleep_interruptible(unsigned int msecs)
1910{
1911 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1912
75bcc8c5
NA
1913 while (timeout && !signal_pending(current))
1914 timeout = schedule_timeout_interruptible(timeout);
1da177e4
LT
1915 return jiffies_to_msecs(timeout);
1916}
1917
1918EXPORT_SYMBOL(msleep_interruptible);