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1/*
2 * arch/s390/kernel/vtime.c
3 * Virtual cpu timer based timer functions.
4 *
5 * S390 version
6 * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 * Author(s): Jan Glauber <jan.glauber@de.ibm.com>
8 */
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/time.h>
13#include <linux/delay.h>
14#include <linux/init.h>
15#include <linux/smp.h>
16#include <linux/types.h>
17#include <linux/timex.h>
18#include <linux/notifier.h>
19#include <linux/kernel_stat.h>
20#include <linux/rcupdate.h>
21#include <linux/posix-timers.h>
22#include <linux/cpu.h>
23#include <linux/kprobes.h>
24
25#include <asm/timer.h>
26#include <asm/irq_regs.h>
27#include <asm/cputime.h>
28#include <asm/irq.h>
29
30static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
31
32DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
33
34static inline __u64 get_vtimer(void)
35{
36 __u64 timer;
37
38 asm volatile("STPT %0" : "=m" (timer));
39 return timer;
40}
41
42static inline void set_vtimer(__u64 expires)
43{
44 __u64 timer;
45
46 asm volatile (" STPT %0\n" /* Store current cpu timer value */
47 " SPT %1" /* Set new value immediately afterwards */
48 : "=m" (timer) : "m" (expires) );
49 S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
50 S390_lowcore.last_update_timer = expires;
51}
52
53/*
54 * Update process times based on virtual cpu times stored by entry.S
55 * to the lowcore fields user_timer, system_timer & steal_clock.
56 */
57static void do_account_vtime(struct task_struct *tsk, int hardirq_offset)
58{
59 struct thread_info *ti = task_thread_info(tsk);
60 __u64 timer, clock, user, system, steal;
61
62 timer = S390_lowcore.last_update_timer;
63 clock = S390_lowcore.last_update_clock;
64 asm volatile (" STPT %0\n" /* Store current cpu timer value */
65 " STCK %1" /* Store current tod clock value */
66 : "=m" (S390_lowcore.last_update_timer),
67 "=m" (S390_lowcore.last_update_clock) );
68 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
69 S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
70
71 user = S390_lowcore.user_timer - ti->user_timer;
72 S390_lowcore.steal_timer -= user;
73 ti->user_timer = S390_lowcore.user_timer;
74 account_user_time(tsk, user, user);
75
76 system = S390_lowcore.system_timer - ti->system_timer;
77 S390_lowcore.steal_timer -= system;
78 ti->system_timer = S390_lowcore.system_timer;
79 account_system_time(tsk, hardirq_offset, system, system);
80
81 steal = S390_lowcore.steal_timer;
82 if ((s64) steal > 0) {
83 S390_lowcore.steal_timer = 0;
84 account_steal_time(steal);
85 }
86}
87
88void account_vtime(struct task_struct *prev, struct task_struct *next)
89{
90 struct thread_info *ti;
91
92 do_account_vtime(prev, 0);
93 ti = task_thread_info(prev);
94 ti->user_timer = S390_lowcore.user_timer;
95 ti->system_timer = S390_lowcore.system_timer;
96 ti = task_thread_info(next);
97 S390_lowcore.user_timer = ti->user_timer;
98 S390_lowcore.system_timer = ti->system_timer;
99}
100
101void account_process_tick(struct task_struct *tsk, int user_tick)
102{
103 do_account_vtime(tsk, HARDIRQ_OFFSET);
104}
105
106/*
107 * Update process times based on virtual cpu times stored by entry.S
108 * to the lowcore fields user_timer, system_timer & steal_clock.
109 */
110void account_system_vtime(struct task_struct *tsk)
111{
112 struct thread_info *ti = task_thread_info(tsk);
113 __u64 timer, system;
114
115 timer = S390_lowcore.last_update_timer;
116 S390_lowcore.last_update_timer = get_vtimer();
117 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
118
119 system = S390_lowcore.system_timer - ti->system_timer;
120 S390_lowcore.steal_timer -= system;
121 ti->system_timer = S390_lowcore.system_timer;
122 account_system_time(tsk, 0, system, system);
123}
124EXPORT_SYMBOL_GPL(account_system_vtime);
125
126void __kprobes vtime_start_cpu(__u64 int_clock, __u64 enter_timer)
127{
128 struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
129 struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
130 __u64 idle_time, expires;
131
132 if (idle->idle_enter == 0ULL)
133 return;
134
135 /* Account time spent with enabled wait psw loaded as idle time. */
136 idle_time = int_clock - idle->idle_enter;
137 account_idle_time(idle_time);
138 S390_lowcore.steal_timer +=
139 idle->idle_enter - S390_lowcore.last_update_clock;
140 S390_lowcore.last_update_clock = int_clock;
141
142 /* Account system time spent going idle. */
143 S390_lowcore.system_timer += S390_lowcore.last_update_timer - vq->idle;
144 S390_lowcore.last_update_timer = enter_timer;
145
146 /* Restart vtime CPU timer */
147 if (vq->do_spt) {
148 /* Program old expire value but first save progress. */
149 expires = vq->idle - enter_timer;
150 expires += get_vtimer();
151 set_vtimer(expires);
152 } else {
153 /* Don't account the CPU timer delta while the cpu was idle. */
154 vq->elapsed -= vq->idle - enter_timer;
155 }
156
157 idle->sequence++;
158 smp_wmb();
159 idle->idle_time += idle_time;
160 idle->idle_enter = 0ULL;
161 idle->idle_count++;
162 smp_wmb();
163 idle->sequence++;
164}
165
166void __kprobes vtime_stop_cpu(void)
167{
168 struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
169 struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
170 psw_t psw;
171
172 /* Wait for external, I/O or machine check interrupt. */
173 psw.mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_IO | PSW_MASK_EXT;
174
175 idle->nohz_delay = 0;
176
177 /* Check if the CPU timer needs to be reprogrammed. */
178 if (vq->do_spt) {
179 __u64 vmax = VTIMER_MAX_SLICE;
180 /*
181 * The inline assembly is equivalent to
182 * vq->idle = get_cpu_timer();
183 * set_cpu_timer(VTIMER_MAX_SLICE);
184 * idle->idle_enter = get_clock();
185 * __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
186 * PSW_MASK_IO | PSW_MASK_EXT);
187 * The difference is that the inline assembly makes sure that
188 * the last three instruction are stpt, stck and lpsw in that
189 * order. This is done to increase the precision.
190 */
191 asm volatile(
192#ifndef CONFIG_64BIT
193 " basr 1,0\n"
194 "0: ahi 1,1f-0b\n"
195 " st 1,4(%2)\n"
196#else /* CONFIG_64BIT */
197 " larl 1,1f\n"
198 " stg 1,8(%2)\n"
199#endif /* CONFIG_64BIT */
200 " stpt 0(%4)\n"
201 " spt 0(%5)\n"
202 " stck 0(%3)\n"
203#ifndef CONFIG_64BIT
204 " lpsw 0(%2)\n"
205#else /* CONFIG_64BIT */
206 " lpswe 0(%2)\n"
207#endif /* CONFIG_64BIT */
208 "1:"
209 : "=m" (idle->idle_enter), "=m" (vq->idle)
210 : "a" (&psw), "a" (&idle->idle_enter),
211 "a" (&vq->idle), "a" (&vmax), "m" (vmax), "m" (psw)
212 : "memory", "cc", "1");
213 } else {
214 /*
215 * The inline assembly is equivalent to
216 * vq->idle = get_cpu_timer();
217 * idle->idle_enter = get_clock();
218 * __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
219 * PSW_MASK_IO | PSW_MASK_EXT);
220 * The difference is that the inline assembly makes sure that
221 * the last three instruction are stpt, stck and lpsw in that
222 * order. This is done to increase the precision.
223 */
224 asm volatile(
225#ifndef CONFIG_64BIT
226 " basr 1,0\n"
227 "0: ahi 1,1f-0b\n"
228 " st 1,4(%2)\n"
229#else /* CONFIG_64BIT */
230 " larl 1,1f\n"
231 " stg 1,8(%2)\n"
232#endif /* CONFIG_64BIT */
233 " stpt 0(%4)\n"
234 " stck 0(%3)\n"
235#ifndef CONFIG_64BIT
236 " lpsw 0(%2)\n"
237#else /* CONFIG_64BIT */
238 " lpswe 0(%2)\n"
239#endif /* CONFIG_64BIT */
240 "1:"
241 : "=m" (idle->idle_enter), "=m" (vq->idle)
242 : "a" (&psw), "a" (&idle->idle_enter),
243 "a" (&vq->idle), "m" (psw)
244 : "memory", "cc", "1");
245 }
246}
247
248cputime64_t s390_get_idle_time(int cpu)
249{
250 struct s390_idle_data *idle;
251 unsigned long long now, idle_time, idle_enter;
252 unsigned int sequence;
253
254 idle = &per_cpu(s390_idle, cpu);
255
256 now = get_clock();
257repeat:
258 sequence = idle->sequence;
259 smp_rmb();
260 if (sequence & 1)
261 goto repeat;
262 idle_time = 0;
263 idle_enter = idle->idle_enter;
264 if (idle_enter != 0ULL && idle_enter < now)
265 idle_time = now - idle_enter;
266 smp_rmb();
267 if (idle->sequence != sequence)
268 goto repeat;
269 return idle_time;
270}
271
272/*
273 * Sorted add to a list. List is linear searched until first bigger
274 * element is found.
275 */
276static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
277{
278 struct vtimer_list *event;
279
280 list_for_each_entry(event, head, entry) {
281 if (event->expires > timer->expires) {
282 list_add_tail(&timer->entry, &event->entry);
283 return;
284 }
285 }
286 list_add_tail(&timer->entry, head);
287}
288
289/*
290 * Do the callback functions of expired vtimer events.
291 * Called from within the interrupt handler.
292 */
293static void do_callbacks(struct list_head *cb_list)
294{
295 struct vtimer_queue *vq;
296 struct vtimer_list *event, *tmp;
297
298 if (list_empty(cb_list))
299 return;
300
301 vq = &__get_cpu_var(virt_cpu_timer);
302
303 list_for_each_entry_safe(event, tmp, cb_list, entry) {
304 list_del_init(&event->entry);
305 (event->function)(event->data);
306 if (event->interval) {
307 /* Recharge interval timer */
308 event->expires = event->interval + vq->elapsed;
309 spin_lock(&vq->lock);
310 list_add_sorted(event, &vq->list);
311 spin_unlock(&vq->lock);
312 }
313 }
314}
315
316/*
317 * Handler for the virtual CPU timer.
318 */
319static void do_cpu_timer_interrupt(unsigned int ext_int_code,
320 unsigned int param32, unsigned long param64)
321{
322 struct vtimer_queue *vq;
323 struct vtimer_list *event, *tmp;
324 struct list_head cb_list; /* the callback queue */
325 __u64 elapsed, next;
326
327 kstat_cpu(smp_processor_id()).irqs[EXTINT_TMR]++;
328 INIT_LIST_HEAD(&cb_list);
329 vq = &__get_cpu_var(virt_cpu_timer);
330
331 /* walk timer list, fire all expired events */
332 spin_lock(&vq->lock);
333
334 elapsed = vq->elapsed + (vq->timer - S390_lowcore.async_enter_timer);
335 BUG_ON((s64) elapsed < 0);
336 vq->elapsed = 0;
337 list_for_each_entry_safe(event, tmp, &vq->list, entry) {
338 if (event->expires < elapsed)
339 /* move expired timer to the callback queue */
340 list_move_tail(&event->entry, &cb_list);
341 else
342 event->expires -= elapsed;
343 }
344 spin_unlock(&vq->lock);
345
346 vq->do_spt = list_empty(&cb_list);
347 do_callbacks(&cb_list);
348
349 /* next event is first in list */
350 next = VTIMER_MAX_SLICE;
351 spin_lock(&vq->lock);
352 if (!list_empty(&vq->list)) {
353 event = list_first_entry(&vq->list, struct vtimer_list, entry);
354 next = event->expires;
355 } else
356 vq->do_spt = 0;
357 spin_unlock(&vq->lock);
358 /*
359 * To improve precision add the time spent by the
360 * interrupt handler to the elapsed time.
361 * Note: CPU timer counts down and we got an interrupt,
362 * the current content is negative
363 */
364 elapsed = S390_lowcore.async_enter_timer - get_vtimer();
365 set_vtimer(next - elapsed);
366 vq->timer = next - elapsed;
367 vq->elapsed = elapsed;
368}
369
370void init_virt_timer(struct vtimer_list *timer)
371{
372 timer->function = NULL;
373 INIT_LIST_HEAD(&timer->entry);
374}
375EXPORT_SYMBOL(init_virt_timer);
376
377static inline int vtimer_pending(struct vtimer_list *timer)
378{
379 return (!list_empty(&timer->entry));
380}
381
382/*
383 * this function should only run on the specified CPU
384 */
385static void internal_add_vtimer(struct vtimer_list *timer)
386{
387 struct vtimer_queue *vq;
388 unsigned long flags;
389 __u64 left, expires;
390
391 vq = &per_cpu(virt_cpu_timer, timer->cpu);
392 spin_lock_irqsave(&vq->lock, flags);
393
394 BUG_ON(timer->cpu != smp_processor_id());
395
396 if (list_empty(&vq->list)) {
397 /* First timer on this cpu, just program it. */
398 list_add(&timer->entry, &vq->list);
399 set_vtimer(timer->expires);
400 vq->timer = timer->expires;
401 vq->elapsed = 0;
402 } else {
403 /* Check progress of old timers. */
404 expires = timer->expires;
405 left = get_vtimer();
406 if (likely((s64) expires < (s64) left)) {
407 /* The new timer expires before the current timer. */
408 set_vtimer(expires);
409 vq->elapsed += vq->timer - left;
410 vq->timer = expires;
411 } else {
412 vq->elapsed += vq->timer - left;
413 vq->timer = left;
414 }
415 /* Insert new timer into per cpu list. */
416 timer->expires += vq->elapsed;
417 list_add_sorted(timer, &vq->list);
418 }
419
420 spin_unlock_irqrestore(&vq->lock, flags);
421 /* release CPU acquired in prepare_vtimer or mod_virt_timer() */
422 put_cpu();
423}
424
425static inline void prepare_vtimer(struct vtimer_list *timer)
426{
427 BUG_ON(!timer->function);
428 BUG_ON(!timer->expires || timer->expires > VTIMER_MAX_SLICE);
429 BUG_ON(vtimer_pending(timer));
430 timer->cpu = get_cpu();
431}
432
433/*
434 * add_virt_timer - add an oneshot virtual CPU timer
435 */
436void add_virt_timer(void *new)
437{
438 struct vtimer_list *timer;
439
440 timer = (struct vtimer_list *)new;
441 prepare_vtimer(timer);
442 timer->interval = 0;
443 internal_add_vtimer(timer);
444}
445EXPORT_SYMBOL(add_virt_timer);
446
447/*
448 * add_virt_timer_int - add an interval virtual CPU timer
449 */
450void add_virt_timer_periodic(void *new)
451{
452 struct vtimer_list *timer;
453
454 timer = (struct vtimer_list *)new;
455 prepare_vtimer(timer);
456 timer->interval = timer->expires;
457 internal_add_vtimer(timer);
458}
459EXPORT_SYMBOL(add_virt_timer_periodic);
460
461int __mod_vtimer(struct vtimer_list *timer, __u64 expires, int periodic)
462{
463 struct vtimer_queue *vq;
464 unsigned long flags;
465 int cpu;
466
467 BUG_ON(!timer->function);
468 BUG_ON(!expires || expires > VTIMER_MAX_SLICE);
469
470 if (timer->expires == expires && vtimer_pending(timer))
471 return 1;
472
473 cpu = get_cpu();
474 vq = &per_cpu(virt_cpu_timer, cpu);
475
476 /* disable interrupts before test if timer is pending */
477 spin_lock_irqsave(&vq->lock, flags);
478
479 /* if timer isn't pending add it on the current CPU */
480 if (!vtimer_pending(timer)) {
481 spin_unlock_irqrestore(&vq->lock, flags);
482
483 if (periodic)
484 timer->interval = expires;
485 else
486 timer->interval = 0;
487 timer->expires = expires;
488 timer->cpu = cpu;
489 internal_add_vtimer(timer);
490 return 0;
491 }
492
493 /* check if we run on the right CPU */
494 BUG_ON(timer->cpu != cpu);
495
496 list_del_init(&timer->entry);
497 timer->expires = expires;
498 if (periodic)
499 timer->interval = expires;
500
501 /* the timer can't expire anymore so we can release the lock */
502 spin_unlock_irqrestore(&vq->lock, flags);
503 internal_add_vtimer(timer);
504 return 1;
505}
506
507/*
508 * If we change a pending timer the function must be called on the CPU
509 * where the timer is running on.
510 *
511 * returns whether it has modified a pending timer (1) or not (0)
512 */
513int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
514{
515 return __mod_vtimer(timer, expires, 0);
516}
517EXPORT_SYMBOL(mod_virt_timer);
518
519/*
520 * If we change a pending timer the function must be called on the CPU
521 * where the timer is running on.
522 *
523 * returns whether it has modified a pending timer (1) or not (0)
524 */
525int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires)
526{
527 return __mod_vtimer(timer, expires, 1);
528}
529EXPORT_SYMBOL(mod_virt_timer_periodic);
530
531/*
532 * delete a virtual timer
533 *
534 * returns whether the deleted timer was pending (1) or not (0)
535 */
536int del_virt_timer(struct vtimer_list *timer)
537{
538 unsigned long flags;
539 struct vtimer_queue *vq;
540
541 /* check if timer is pending */
542 if (!vtimer_pending(timer))
543 return 0;
544
545 vq = &per_cpu(virt_cpu_timer, timer->cpu);
546 spin_lock_irqsave(&vq->lock, flags);
547
548 /* we don't interrupt a running timer, just let it expire! */
549 list_del_init(&timer->entry);
550
551 spin_unlock_irqrestore(&vq->lock, flags);
552 return 1;
553}
554EXPORT_SYMBOL(del_virt_timer);
555
556/*
557 * Start the virtual CPU timer on the current CPU.
558 */
559void init_cpu_vtimer(void)
560{
561 struct vtimer_queue *vq;
562
563 /* initialize per cpu vtimer structure */
564 vq = &__get_cpu_var(virt_cpu_timer);
565 INIT_LIST_HEAD(&vq->list);
566 spin_lock_init(&vq->lock);
567
568 /* enable cpu timer interrupts */
569 __ctl_set_bit(0,10);
570}
571
572static int __cpuinit s390_nohz_notify(struct notifier_block *self,
573 unsigned long action, void *hcpu)
574{
575 struct s390_idle_data *idle;
576 long cpu = (long) hcpu;
577
578 idle = &per_cpu(s390_idle, cpu);
579 switch (action) {
580 case CPU_DYING:
581 case CPU_DYING_FROZEN:
582 idle->nohz_delay = 0;
583 default:
584 break;
585 }
586 return NOTIFY_OK;
587}
588
589void __init vtime_init(void)
590{
591 /* request the cpu timer external interrupt */
592 if (register_external_interrupt(0x1005, do_cpu_timer_interrupt))
593 panic("Couldn't request external interrupt 0x1005");
594
595 /* Enable cpu timer interrupts on the boot cpu. */
596 init_cpu_vtimer();
597 cpu_notifier(s390_nohz_notify, 0);
598}
599
1/*
2 * Virtual cpu timer based timer functions.
3 *
4 * Copyright IBM Corp. 2004, 2012
5 * Author(s): Jan Glauber <jan.glauber@de.ibm.com>
6 */
7
8#include <linux/kernel_stat.h>
9#include <linux/export.h>
10#include <linux/kernel.h>
11#include <linux/timex.h>
12#include <linux/types.h>
13#include <linux/time.h>
14
15#include <asm/cputime.h>
16#include <asm/vtimer.h>
17#include <asm/vtime.h>
18#include <asm/cpu_mf.h>
19#include <asm/smp.h>
20
21static void virt_timer_expire(void);
22
23static LIST_HEAD(virt_timer_list);
24static DEFINE_SPINLOCK(virt_timer_lock);
25static atomic64_t virt_timer_current;
26static atomic64_t virt_timer_elapsed;
27
28DEFINE_PER_CPU(u64, mt_cycles[8]);
29static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
30static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
31static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
32
33static inline u64 get_vtimer(void)
34{
35 u64 timer;
36
37 asm volatile("stpt %0" : "=m" (timer));
38 return timer;
39}
40
41static inline void set_vtimer(u64 expires)
42{
43 u64 timer;
44
45 asm volatile(
46 " stpt %0\n" /* Store current cpu timer value */
47 " spt %1" /* Set new value imm. afterwards */
48 : "=m" (timer) : "m" (expires));
49 S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
50 S390_lowcore.last_update_timer = expires;
51}
52
53static inline int virt_timer_forward(u64 elapsed)
54{
55 BUG_ON(!irqs_disabled());
56
57 if (list_empty(&virt_timer_list))
58 return 0;
59 elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
60 return elapsed >= atomic64_read(&virt_timer_current);
61}
62
63static void update_mt_scaling(void)
64{
65 u64 cycles_new[8], *cycles_old;
66 u64 delta, fac, mult, div;
67 int i;
68
69 stcctm5(smp_cpu_mtid + 1, cycles_new);
70 cycles_old = this_cpu_ptr(mt_cycles);
71 fac = 1;
72 mult = div = 0;
73 for (i = 0; i <= smp_cpu_mtid; i++) {
74 delta = cycles_new[i] - cycles_old[i];
75 div += delta;
76 mult *= i + 1;
77 mult += delta * fac;
78 fac *= i + 1;
79 }
80 div *= fac;
81 if (div > 0) {
82 /* Update scaling factor */
83 __this_cpu_write(mt_scaling_mult, mult);
84 __this_cpu_write(mt_scaling_div, div);
85 memcpy(cycles_old, cycles_new,
86 sizeof(u64) * (smp_cpu_mtid + 1));
87 }
88 __this_cpu_write(mt_scaling_jiffies, jiffies_64);
89}
90
91/*
92 * Update process times based on virtual cpu times stored by entry.S
93 * to the lowcore fields user_timer, system_timer & steal_clock.
94 */
95static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
96{
97 struct thread_info *ti = task_thread_info(tsk);
98 u64 timer, clock, user, system, steal;
99 u64 user_scaled, system_scaled;
100
101 timer = S390_lowcore.last_update_timer;
102 clock = S390_lowcore.last_update_clock;
103 asm volatile(
104 " stpt %0\n" /* Store current cpu timer value */
105#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
106 " stckf %1" /* Store current tod clock value */
107#else
108 " stck %1" /* Store current tod clock value */
109#endif
110 : "=m" (S390_lowcore.last_update_timer),
111 "=m" (S390_lowcore.last_update_clock));
112 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
113 S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
114
115 /* Update MT utilization calculation */
116 if (smp_cpu_mtid &&
117 time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
118 update_mt_scaling();
119
120 user = S390_lowcore.user_timer - ti->user_timer;
121 S390_lowcore.steal_timer -= user;
122 ti->user_timer = S390_lowcore.user_timer;
123
124 system = S390_lowcore.system_timer - ti->system_timer;
125 S390_lowcore.steal_timer -= system;
126 ti->system_timer = S390_lowcore.system_timer;
127
128 user_scaled = user;
129 system_scaled = system;
130 /* Do MT utilization scaling */
131 if (smp_cpu_mtid) {
132 u64 mult = __this_cpu_read(mt_scaling_mult);
133 u64 div = __this_cpu_read(mt_scaling_div);
134
135 user_scaled = (user_scaled * mult) / div;
136 system_scaled = (system_scaled * mult) / div;
137 }
138 account_user_time(tsk, user, user_scaled);
139 account_system_time(tsk, hardirq_offset, system, system_scaled);
140
141 steal = S390_lowcore.steal_timer;
142 if ((s64) steal > 0) {
143 S390_lowcore.steal_timer = 0;
144 account_steal_time(steal);
145 }
146
147 return virt_timer_forward(user + system);
148}
149
150void vtime_task_switch(struct task_struct *prev)
151{
152 struct thread_info *ti;
153
154 do_account_vtime(prev, 0);
155 ti = task_thread_info(prev);
156 ti->user_timer = S390_lowcore.user_timer;
157 ti->system_timer = S390_lowcore.system_timer;
158 ti = task_thread_info(current);
159 S390_lowcore.user_timer = ti->user_timer;
160 S390_lowcore.system_timer = ti->system_timer;
161}
162
163/*
164 * In s390, accounting pending user time also implies
165 * accounting system time in order to correctly compute
166 * the stolen time accounting.
167 */
168void vtime_account_user(struct task_struct *tsk)
169{
170 if (do_account_vtime(tsk, HARDIRQ_OFFSET))
171 virt_timer_expire();
172}
173
174/*
175 * Update process times based on virtual cpu times stored by entry.S
176 * to the lowcore fields user_timer, system_timer & steal_clock.
177 */
178void vtime_account_irq_enter(struct task_struct *tsk)
179{
180 struct thread_info *ti = task_thread_info(tsk);
181 u64 timer, system, system_scaled;
182
183 timer = S390_lowcore.last_update_timer;
184 S390_lowcore.last_update_timer = get_vtimer();
185 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
186
187 /* Update MT utilization calculation */
188 if (smp_cpu_mtid &&
189 time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
190 update_mt_scaling();
191
192 system = S390_lowcore.system_timer - ti->system_timer;
193 S390_lowcore.steal_timer -= system;
194 ti->system_timer = S390_lowcore.system_timer;
195 system_scaled = system;
196 /* Do MT utilization scaling */
197 if (smp_cpu_mtid) {
198 u64 mult = __this_cpu_read(mt_scaling_mult);
199 u64 div = __this_cpu_read(mt_scaling_div);
200
201 system_scaled = (system_scaled * mult) / div;
202 }
203 account_system_time(tsk, 0, system, system_scaled);
204
205 virt_timer_forward(system);
206}
207EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
208
209void vtime_account_system(struct task_struct *tsk)
210__attribute__((alias("vtime_account_irq_enter")));
211EXPORT_SYMBOL_GPL(vtime_account_system);
212
213/*
214 * Sorted add to a list. List is linear searched until first bigger
215 * element is found.
216 */
217static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
218{
219 struct vtimer_list *tmp;
220
221 list_for_each_entry(tmp, head, entry) {
222 if (tmp->expires > timer->expires) {
223 list_add_tail(&timer->entry, &tmp->entry);
224 return;
225 }
226 }
227 list_add_tail(&timer->entry, head);
228}
229
230/*
231 * Handler for expired virtual CPU timer.
232 */
233static void virt_timer_expire(void)
234{
235 struct vtimer_list *timer, *tmp;
236 unsigned long elapsed;
237 LIST_HEAD(cb_list);
238
239 /* walk timer list, fire all expired timers */
240 spin_lock(&virt_timer_lock);
241 elapsed = atomic64_read(&virt_timer_elapsed);
242 list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
243 if (timer->expires < elapsed)
244 /* move expired timer to the callback queue */
245 list_move_tail(&timer->entry, &cb_list);
246 else
247 timer->expires -= elapsed;
248 }
249 if (!list_empty(&virt_timer_list)) {
250 timer = list_first_entry(&virt_timer_list,
251 struct vtimer_list, entry);
252 atomic64_set(&virt_timer_current, timer->expires);
253 }
254 atomic64_sub(elapsed, &virt_timer_elapsed);
255 spin_unlock(&virt_timer_lock);
256
257 /* Do callbacks and recharge periodic timers */
258 list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
259 list_del_init(&timer->entry);
260 timer->function(timer->data);
261 if (timer->interval) {
262 /* Recharge interval timer */
263 timer->expires = timer->interval +
264 atomic64_read(&virt_timer_elapsed);
265 spin_lock(&virt_timer_lock);
266 list_add_sorted(timer, &virt_timer_list);
267 spin_unlock(&virt_timer_lock);
268 }
269 }
270}
271
272void init_virt_timer(struct vtimer_list *timer)
273{
274 timer->function = NULL;
275 INIT_LIST_HEAD(&timer->entry);
276}
277EXPORT_SYMBOL(init_virt_timer);
278
279static inline int vtimer_pending(struct vtimer_list *timer)
280{
281 return !list_empty(&timer->entry);
282}
283
284static void internal_add_vtimer(struct vtimer_list *timer)
285{
286 if (list_empty(&virt_timer_list)) {
287 /* First timer, just program it. */
288 atomic64_set(&virt_timer_current, timer->expires);
289 atomic64_set(&virt_timer_elapsed, 0);
290 list_add(&timer->entry, &virt_timer_list);
291 } else {
292 /* Update timer against current base. */
293 timer->expires += atomic64_read(&virt_timer_elapsed);
294 if (likely((s64) timer->expires <
295 (s64) atomic64_read(&virt_timer_current)))
296 /* The new timer expires before the current timer. */
297 atomic64_set(&virt_timer_current, timer->expires);
298 /* Insert new timer into the list. */
299 list_add_sorted(timer, &virt_timer_list);
300 }
301}
302
303static void __add_vtimer(struct vtimer_list *timer, int periodic)
304{
305 unsigned long flags;
306
307 timer->interval = periodic ? timer->expires : 0;
308 spin_lock_irqsave(&virt_timer_lock, flags);
309 internal_add_vtimer(timer);
310 spin_unlock_irqrestore(&virt_timer_lock, flags);
311}
312
313/*
314 * add_virt_timer - add an oneshot virtual CPU timer
315 */
316void add_virt_timer(struct vtimer_list *timer)
317{
318 __add_vtimer(timer, 0);
319}
320EXPORT_SYMBOL(add_virt_timer);
321
322/*
323 * add_virt_timer_int - add an interval virtual CPU timer
324 */
325void add_virt_timer_periodic(struct vtimer_list *timer)
326{
327 __add_vtimer(timer, 1);
328}
329EXPORT_SYMBOL(add_virt_timer_periodic);
330
331static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
332{
333 unsigned long flags;
334 int rc;
335
336 BUG_ON(!timer->function);
337
338 if (timer->expires == expires && vtimer_pending(timer))
339 return 1;
340 spin_lock_irqsave(&virt_timer_lock, flags);
341 rc = vtimer_pending(timer);
342 if (rc)
343 list_del_init(&timer->entry);
344 timer->interval = periodic ? expires : 0;
345 timer->expires = expires;
346 internal_add_vtimer(timer);
347 spin_unlock_irqrestore(&virt_timer_lock, flags);
348 return rc;
349}
350
351/*
352 * returns whether it has modified a pending timer (1) or not (0)
353 */
354int mod_virt_timer(struct vtimer_list *timer, u64 expires)
355{
356 return __mod_vtimer(timer, expires, 0);
357}
358EXPORT_SYMBOL(mod_virt_timer);
359
360/*
361 * returns whether it has modified a pending timer (1) or not (0)
362 */
363int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
364{
365 return __mod_vtimer(timer, expires, 1);
366}
367EXPORT_SYMBOL(mod_virt_timer_periodic);
368
369/*
370 * Delete a virtual timer.
371 *
372 * returns whether the deleted timer was pending (1) or not (0)
373 */
374int del_virt_timer(struct vtimer_list *timer)
375{
376 unsigned long flags;
377
378 if (!vtimer_pending(timer))
379 return 0;
380 spin_lock_irqsave(&virt_timer_lock, flags);
381 list_del_init(&timer->entry);
382 spin_unlock_irqrestore(&virt_timer_lock, flags);
383 return 1;
384}
385EXPORT_SYMBOL(del_virt_timer);
386
387/*
388 * Start the virtual CPU timer on the current CPU.
389 */
390void vtime_init(void)
391{
392 /* set initial cpu timer */
393 set_vtimer(VTIMER_MAX_SLICE);
394 /* Setup initial MT scaling values */
395 if (smp_cpu_mtid) {
396 __this_cpu_write(mt_scaling_jiffies, jiffies);
397 __this_cpu_write(mt_scaling_mult, 1);
398 __this_cpu_write(mt_scaling_div, 1);
399 stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
400 }
401}