Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 LT |
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 | ||
23 | #include <asm/s390_ext.h> | |
24 | #include <asm/timer.h> | |
5a489b98 | 25 | #include <asm/irq_regs.h> |
1da177e4 | 26 | |
1da177e4 LT |
27 | static ext_int_info_t ext_int_info_timer; |
28 | DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer); | |
29 | ||
30 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING | |
31 | /* | |
32 | * Update process times based on virtual cpu times stored by entry.S | |
33 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
34 | */ | |
1f1c12af | 35 | void account_tick_vtime(struct task_struct *tsk) |
1da177e4 LT |
36 | { |
37 | cputime_t cputime; | |
38 | __u64 timer, clock; | |
39 | int rcu_user_flag; | |
40 | ||
41 | timer = S390_lowcore.last_update_timer; | |
42 | clock = S390_lowcore.last_update_clock; | |
43 | asm volatile (" STPT %0\n" /* Store current cpu timer value */ | |
44 | " STCK %1" /* Store current tod clock value */ | |
45 | : "=m" (S390_lowcore.last_update_timer), | |
46 | "=m" (S390_lowcore.last_update_clock) ); | |
47 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; | |
48 | S390_lowcore.steal_clock += S390_lowcore.last_update_clock - clock; | |
49 | ||
50 | cputime = S390_lowcore.user_timer >> 12; | |
51 | rcu_user_flag = cputime != 0; | |
52 | S390_lowcore.user_timer -= cputime << 12; | |
53 | S390_lowcore.steal_clock -= cputime << 12; | |
54 | account_user_time(tsk, cputime); | |
55 | ||
56 | cputime = S390_lowcore.system_timer >> 12; | |
57 | S390_lowcore.system_timer -= cputime << 12; | |
58 | S390_lowcore.steal_clock -= cputime << 12; | |
59 | account_system_time(tsk, HARDIRQ_OFFSET, cputime); | |
60 | ||
61 | cputime = S390_lowcore.steal_clock; | |
62 | if ((__s64) cputime > 0) { | |
63 | cputime >>= 12; | |
64 | S390_lowcore.steal_clock -= cputime << 12; | |
65 | account_steal_time(tsk, cputime); | |
66 | } | |
67 | ||
68 | run_local_timers(); | |
69 | if (rcu_pending(smp_processor_id())) | |
70 | rcu_check_callbacks(smp_processor_id(), rcu_user_flag); | |
71 | scheduler_tick(); | |
72 | run_posix_cpu_timers(tsk); | |
73 | } | |
74 | ||
1f1c12af MS |
75 | /* |
76 | * Update process times based on virtual cpu times stored by entry.S | |
77 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
78 | */ | |
79 | void account_vtime(struct task_struct *tsk) | |
80 | { | |
81 | cputime_t cputime; | |
82 | __u64 timer; | |
83 | ||
84 | timer = S390_lowcore.last_update_timer; | |
85 | asm volatile (" STPT %0" /* Store current cpu timer value */ | |
86 | : "=m" (S390_lowcore.last_update_timer) ); | |
87 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; | |
88 | ||
89 | cputime = S390_lowcore.user_timer >> 12; | |
90 | S390_lowcore.user_timer -= cputime << 12; | |
91 | S390_lowcore.steal_clock -= cputime << 12; | |
92 | account_user_time(tsk, cputime); | |
93 | ||
94 | cputime = S390_lowcore.system_timer >> 12; | |
95 | S390_lowcore.system_timer -= cputime << 12; | |
96 | S390_lowcore.steal_clock -= cputime << 12; | |
97 | account_system_time(tsk, 0, cputime); | |
98 | } | |
99 | ||
1da177e4 LT |
100 | /* |
101 | * Update process times based on virtual cpu times stored by entry.S | |
102 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
103 | */ | |
104 | void account_system_vtime(struct task_struct *tsk) | |
105 | { | |
106 | cputime_t cputime; | |
107 | __u64 timer; | |
108 | ||
109 | timer = S390_lowcore.last_update_timer; | |
110 | asm volatile (" STPT %0" /* Store current cpu timer value */ | |
111 | : "=m" (S390_lowcore.last_update_timer) ); | |
112 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; | |
113 | ||
114 | cputime = S390_lowcore.system_timer >> 12; | |
115 | S390_lowcore.system_timer -= cputime << 12; | |
116 | S390_lowcore.steal_clock -= cputime << 12; | |
117 | account_system_time(tsk, 0, cputime); | |
118 | } | |
119 | ||
120 | static inline void set_vtimer(__u64 expires) | |
121 | { | |
122 | __u64 timer; | |
123 | ||
124 | asm volatile (" STPT %0\n" /* Store current cpu timer value */ | |
125 | " SPT %1" /* Set new value immediatly afterwards */ | |
126 | : "=m" (timer) : "m" (expires) ); | |
127 | S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer; | |
128 | S390_lowcore.last_update_timer = expires; | |
129 | ||
130 | /* store expire time for this CPU timer */ | |
131 | per_cpu(virt_cpu_timer, smp_processor_id()).to_expire = expires; | |
132 | } | |
133 | #else | |
134 | static inline void set_vtimer(__u64 expires) | |
135 | { | |
136 | S390_lowcore.last_update_timer = expires; | |
137 | asm volatile ("SPT %0" : : "m" (S390_lowcore.last_update_timer)); | |
138 | ||
139 | /* store expire time for this CPU timer */ | |
140 | per_cpu(virt_cpu_timer, smp_processor_id()).to_expire = expires; | |
141 | } | |
142 | #endif | |
143 | ||
144 | static void start_cpu_timer(void) | |
145 | { | |
146 | struct vtimer_queue *vt_list; | |
147 | ||
148 | vt_list = &per_cpu(virt_cpu_timer, smp_processor_id()); | |
4b7e0706 MS |
149 | |
150 | /* CPU timer interrupt is pending, don't reprogramm it */ | |
151 | if (vt_list->idle & 1LL<<63) | |
152 | return; | |
153 | ||
154 | if (!list_empty(&vt_list->list)) | |
155 | set_vtimer(vt_list->idle); | |
1da177e4 LT |
156 | } |
157 | ||
158 | static void stop_cpu_timer(void) | |
159 | { | |
1da177e4 LT |
160 | struct vtimer_queue *vt_list; |
161 | ||
162 | vt_list = &per_cpu(virt_cpu_timer, smp_processor_id()); | |
163 | ||
164 | /* nothing to do */ | |
165 | if (list_empty(&vt_list->list)) { | |
166 | vt_list->idle = VTIMER_MAX_SLICE; | |
167 | goto fire; | |
168 | } | |
169 | ||
4b7e0706 MS |
170 | /* store the actual expire value */ |
171 | asm volatile ("STPT %0" : "=m" (vt_list->idle)); | |
1da177e4 LT |
172 | |
173 | /* | |
4b7e0706 MS |
174 | * If the CPU timer is negative we don't reprogramm |
175 | * it because we will get instantly an interrupt. | |
1da177e4 | 176 | */ |
4b7e0706 | 177 | if (vt_list->idle & 1LL<<63) |
1da177e4 | 178 | return; |
1da177e4 | 179 | |
4b7e0706 | 180 | vt_list->offset += vt_list->to_expire - vt_list->idle; |
1da177e4 LT |
181 | |
182 | /* | |
183 | * We cannot halt the CPU timer, we just write a value that | |
184 | * nearly never expires (only after 71 years) and re-write | |
185 | * the stored expire value if we continue the timer | |
186 | */ | |
187 | fire: | |
188 | set_vtimer(VTIMER_MAX_SLICE); | |
189 | } | |
190 | ||
191 | /* | |
192 | * Sorted add to a list. List is linear searched until first bigger | |
193 | * element is found. | |
194 | */ | |
195 | static void list_add_sorted(struct vtimer_list *timer, struct list_head *head) | |
196 | { | |
197 | struct vtimer_list *event; | |
198 | ||
199 | list_for_each_entry(event, head, entry) { | |
200 | if (event->expires > timer->expires) { | |
201 | list_add_tail(&timer->entry, &event->entry); | |
202 | return; | |
203 | } | |
204 | } | |
205 | list_add_tail(&timer->entry, head); | |
206 | } | |
207 | ||
208 | /* | |
209 | * Do the callback functions of expired vtimer events. | |
210 | * Called from within the interrupt handler. | |
211 | */ | |
212 | static void do_callbacks(struct list_head *cb_list, struct pt_regs *regs) | |
213 | { | |
214 | struct vtimer_queue *vt_list; | |
215 | struct vtimer_list *event, *tmp; | |
216 | void (*fn)(unsigned long, struct pt_regs*); | |
217 | unsigned long data; | |
218 | ||
219 | if (list_empty(cb_list)) | |
220 | return; | |
221 | ||
222 | vt_list = &per_cpu(virt_cpu_timer, smp_processor_id()); | |
223 | ||
224 | list_for_each_entry_safe(event, tmp, cb_list, entry) { | |
225 | fn = event->function; | |
226 | data = event->data; | |
227 | fn(data, regs); | |
228 | ||
229 | if (!event->interval) | |
230 | /* delete one shot timer */ | |
231 | list_del_init(&event->entry); | |
232 | else { | |
233 | /* move interval timer back to list */ | |
234 | spin_lock(&vt_list->lock); | |
235 | list_del_init(&event->entry); | |
236 | list_add_sorted(event, &vt_list->list); | |
237 | spin_unlock(&vt_list->lock); | |
238 | } | |
239 | } | |
240 | } | |
241 | ||
242 | /* | |
243 | * Handler for the virtual CPU timer. | |
244 | */ | |
5a489b98 | 245 | static void do_cpu_timer_interrupt(__u16 error_code) |
1da177e4 LT |
246 | { |
247 | int cpu; | |
248 | __u64 next, delta; | |
249 | struct vtimer_queue *vt_list; | |
250 | struct vtimer_list *event, *tmp; | |
251 | struct list_head *ptr; | |
252 | /* the callback queue */ | |
253 | struct list_head cb_list; | |
254 | ||
255 | INIT_LIST_HEAD(&cb_list); | |
256 | cpu = smp_processor_id(); | |
257 | vt_list = &per_cpu(virt_cpu_timer, cpu); | |
258 | ||
259 | /* walk timer list, fire all expired events */ | |
260 | spin_lock(&vt_list->lock); | |
261 | ||
262 | if (vt_list->to_expire < VTIMER_MAX_SLICE) | |
263 | vt_list->offset += vt_list->to_expire; | |
264 | ||
265 | list_for_each_entry_safe(event, tmp, &vt_list->list, entry) { | |
266 | if (event->expires > vt_list->offset) | |
267 | /* found first unexpired event, leave */ | |
268 | break; | |
269 | ||
270 | /* re-charge interval timer, we have to add the offset */ | |
271 | if (event->interval) | |
272 | event->expires = event->interval + vt_list->offset; | |
273 | ||
274 | /* move expired timer to the callback queue */ | |
275 | list_move_tail(&event->entry, &cb_list); | |
276 | } | |
277 | spin_unlock(&vt_list->lock); | |
5a489b98 | 278 | do_callbacks(&cb_list, get_irq_regs()); |
1da177e4 LT |
279 | |
280 | /* next event is first in list */ | |
281 | spin_lock(&vt_list->lock); | |
282 | if (!list_empty(&vt_list->list)) { | |
283 | ptr = vt_list->list.next; | |
284 | event = list_entry(ptr, struct vtimer_list, entry); | |
285 | next = event->expires - vt_list->offset; | |
286 | ||
287 | /* add the expired time from this interrupt handler | |
288 | * and the callback functions | |
289 | */ | |
290 | asm volatile ("STPT %0" : "=m" (delta)); | |
291 | delta = 0xffffffffffffffffLL - delta + 1; | |
292 | vt_list->offset += delta; | |
293 | next -= delta; | |
294 | } else { | |
295 | vt_list->offset = 0; | |
296 | next = VTIMER_MAX_SLICE; | |
297 | } | |
298 | spin_unlock(&vt_list->lock); | |
299 | set_vtimer(next); | |
300 | } | |
301 | ||
302 | void init_virt_timer(struct vtimer_list *timer) | |
303 | { | |
1da177e4 LT |
304 | timer->function = NULL; |
305 | INIT_LIST_HEAD(&timer->entry); | |
306 | spin_lock_init(&timer->lock); | |
307 | } | |
308 | EXPORT_SYMBOL(init_virt_timer); | |
309 | ||
1da177e4 LT |
310 | static inline int vtimer_pending(struct vtimer_list *timer) |
311 | { | |
312 | return (!list_empty(&timer->entry)); | |
313 | } | |
314 | ||
315 | /* | |
316 | * this function should only run on the specified CPU | |
317 | */ | |
318 | static void internal_add_vtimer(struct vtimer_list *timer) | |
319 | { | |
320 | unsigned long flags; | |
321 | __u64 done; | |
322 | struct vtimer_list *event; | |
323 | struct vtimer_queue *vt_list; | |
324 | ||
325 | vt_list = &per_cpu(virt_cpu_timer, timer->cpu); | |
326 | spin_lock_irqsave(&vt_list->lock, flags); | |
327 | ||
328 | if (timer->cpu != smp_processor_id()) | |
329 | printk("internal_add_vtimer: BUG, running on wrong CPU"); | |
330 | ||
331 | /* if list is empty we only have to set the timer */ | |
332 | if (list_empty(&vt_list->list)) { | |
333 | /* reset the offset, this may happen if the last timer was | |
334 | * just deleted by mod_virt_timer and the interrupt | |
335 | * didn't happen until here | |
336 | */ | |
337 | vt_list->offset = 0; | |
338 | goto fire; | |
339 | } | |
340 | ||
341 | /* save progress */ | |
342 | asm volatile ("STPT %0" : "=m" (done)); | |
343 | ||
344 | /* calculate completed work */ | |
345 | done = vt_list->to_expire - done + vt_list->offset; | |
346 | vt_list->offset = 0; | |
347 | ||
348 | list_for_each_entry(event, &vt_list->list, entry) | |
349 | event->expires -= done; | |
350 | ||
351 | fire: | |
352 | list_add_sorted(timer, &vt_list->list); | |
353 | ||
354 | /* get first element, which is the next vtimer slice */ | |
355 | event = list_entry(vt_list->list.next, struct vtimer_list, entry); | |
356 | ||
357 | set_vtimer(event->expires); | |
358 | spin_unlock_irqrestore(&vt_list->lock, flags); | |
d6e05edc | 359 | /* release CPU acquired in prepare_vtimer or mod_virt_timer() */ |
1da177e4 LT |
360 | put_cpu(); |
361 | } | |
362 | ||
363 | static inline int prepare_vtimer(struct vtimer_list *timer) | |
364 | { | |
dfc4f94d | 365 | if (!timer->function) { |
1da177e4 LT |
366 | printk("add_virt_timer: uninitialized timer\n"); |
367 | return -EINVAL; | |
368 | } | |
369 | ||
370 | if (!timer->expires || timer->expires > VTIMER_MAX_SLICE) { | |
371 | printk("add_virt_timer: invalid timer expire value!\n"); | |
372 | return -EINVAL; | |
373 | } | |
374 | ||
375 | if (vtimer_pending(timer)) { | |
376 | printk("add_virt_timer: timer pending\n"); | |
377 | return -EBUSY; | |
378 | } | |
379 | ||
380 | timer->cpu = get_cpu(); | |
381 | return 0; | |
382 | } | |
383 | ||
384 | /* | |
385 | * add_virt_timer - add an oneshot virtual CPU timer | |
386 | */ | |
387 | void add_virt_timer(void *new) | |
388 | { | |
389 | struct vtimer_list *timer; | |
390 | ||
391 | timer = (struct vtimer_list *)new; | |
392 | ||
393 | if (prepare_vtimer(timer) < 0) | |
394 | return; | |
395 | ||
396 | timer->interval = 0; | |
397 | internal_add_vtimer(timer); | |
398 | } | |
399 | EXPORT_SYMBOL(add_virt_timer); | |
400 | ||
401 | /* | |
402 | * add_virt_timer_int - add an interval virtual CPU timer | |
403 | */ | |
404 | void add_virt_timer_periodic(void *new) | |
405 | { | |
406 | struct vtimer_list *timer; | |
407 | ||
408 | timer = (struct vtimer_list *)new; | |
409 | ||
410 | if (prepare_vtimer(timer) < 0) | |
411 | return; | |
412 | ||
413 | timer->interval = timer->expires; | |
414 | internal_add_vtimer(timer); | |
415 | } | |
416 | EXPORT_SYMBOL(add_virt_timer_periodic); | |
417 | ||
418 | /* | |
419 | * If we change a pending timer the function must be called on the CPU | |
420 | * where the timer is running on, e.g. by smp_call_function_on() | |
421 | * | |
422 | * The original mod_timer adds the timer if it is not pending. For compatibility | |
423 | * we do the same. The timer will be added on the current CPU as a oneshot timer. | |
424 | * | |
425 | * returns whether it has modified a pending timer (1) or not (0) | |
426 | */ | |
427 | int mod_virt_timer(struct vtimer_list *timer, __u64 expires) | |
428 | { | |
429 | struct vtimer_queue *vt_list; | |
430 | unsigned long flags; | |
431 | int cpu; | |
432 | ||
dfc4f94d | 433 | if (!timer->function) { |
1da177e4 LT |
434 | printk("mod_virt_timer: uninitialized timer\n"); |
435 | return -EINVAL; | |
436 | } | |
437 | ||
438 | if (!expires || expires > VTIMER_MAX_SLICE) { | |
439 | printk("mod_virt_timer: invalid expire range\n"); | |
440 | return -EINVAL; | |
441 | } | |
442 | ||
443 | /* | |
444 | * This is a common optimization triggered by the | |
445 | * networking code - if the timer is re-modified | |
446 | * to be the same thing then just return: | |
447 | */ | |
448 | if (timer->expires == expires && vtimer_pending(timer)) | |
449 | return 1; | |
450 | ||
451 | cpu = get_cpu(); | |
452 | vt_list = &per_cpu(virt_cpu_timer, cpu); | |
453 | ||
454 | /* disable interrupts before test if timer is pending */ | |
455 | spin_lock_irqsave(&vt_list->lock, flags); | |
456 | ||
457 | /* if timer isn't pending add it on the current CPU */ | |
458 | if (!vtimer_pending(timer)) { | |
459 | spin_unlock_irqrestore(&vt_list->lock, flags); | |
460 | /* we do not activate an interval timer with mod_virt_timer */ | |
461 | timer->interval = 0; | |
462 | timer->expires = expires; | |
463 | timer->cpu = cpu; | |
464 | internal_add_vtimer(timer); | |
465 | return 0; | |
466 | } | |
467 | ||
468 | /* check if we run on the right CPU */ | |
469 | if (timer->cpu != cpu) { | |
470 | printk("mod_virt_timer: running on wrong CPU, check your code\n"); | |
471 | spin_unlock_irqrestore(&vt_list->lock, flags); | |
472 | put_cpu(); | |
473 | return -EINVAL; | |
474 | } | |
475 | ||
476 | list_del_init(&timer->entry); | |
477 | timer->expires = expires; | |
478 | ||
479 | /* also change the interval if we have an interval timer */ | |
480 | if (timer->interval) | |
481 | timer->interval = expires; | |
482 | ||
483 | /* the timer can't expire anymore so we can release the lock */ | |
484 | spin_unlock_irqrestore(&vt_list->lock, flags); | |
485 | internal_add_vtimer(timer); | |
486 | return 1; | |
487 | } | |
488 | EXPORT_SYMBOL(mod_virt_timer); | |
489 | ||
490 | /* | |
491 | * delete a virtual timer | |
492 | * | |
493 | * returns whether the deleted timer was pending (1) or not (0) | |
494 | */ | |
495 | int del_virt_timer(struct vtimer_list *timer) | |
496 | { | |
497 | unsigned long flags; | |
498 | struct vtimer_queue *vt_list; | |
499 | ||
1da177e4 LT |
500 | /* check if timer is pending */ |
501 | if (!vtimer_pending(timer)) | |
502 | return 0; | |
503 | ||
504 | vt_list = &per_cpu(virt_cpu_timer, timer->cpu); | |
505 | spin_lock_irqsave(&vt_list->lock, flags); | |
506 | ||
507 | /* we don't interrupt a running timer, just let it expire! */ | |
508 | list_del_init(&timer->entry); | |
509 | ||
510 | /* last timer removed */ | |
511 | if (list_empty(&vt_list->list)) { | |
512 | vt_list->to_expire = 0; | |
513 | vt_list->offset = 0; | |
514 | } | |
515 | ||
516 | spin_unlock_irqrestore(&vt_list->lock, flags); | |
517 | return 1; | |
518 | } | |
519 | EXPORT_SYMBOL(del_virt_timer); | |
520 | ||
521 | /* | |
522 | * Start the virtual CPU timer on the current CPU. | |
523 | */ | |
524 | void init_cpu_vtimer(void) | |
525 | { | |
526 | struct vtimer_queue *vt_list; | |
527 | unsigned long cr0; | |
528 | ||
529 | /* kick the virtual timer */ | |
530 | S390_lowcore.exit_timer = VTIMER_MAX_SLICE; | |
531 | S390_lowcore.last_update_timer = VTIMER_MAX_SLICE; | |
532 | asm volatile ("SPT %0" : : "m" (S390_lowcore.last_update_timer)); | |
533 | asm volatile ("STCK %0" : "=m" (S390_lowcore.last_update_clock)); | |
534 | __ctl_store(cr0, 0, 0); | |
535 | cr0 |= 0x400; | |
536 | __ctl_load(cr0, 0, 0); | |
537 | ||
538 | vt_list = &per_cpu(virt_cpu_timer, smp_processor_id()); | |
539 | INIT_LIST_HEAD(&vt_list->list); | |
540 | spin_lock_init(&vt_list->lock); | |
541 | vt_list->to_expire = 0; | |
542 | vt_list->offset = 0; | |
543 | vt_list->idle = 0; | |
544 | ||
545 | } | |
546 | ||
547 | static int vtimer_idle_notify(struct notifier_block *self, | |
548 | unsigned long action, void *hcpu) | |
549 | { | |
550 | switch (action) { | |
551 | case CPU_IDLE: | |
552 | stop_cpu_timer(); | |
553 | break; | |
554 | case CPU_NOT_IDLE: | |
555 | start_cpu_timer(); | |
556 | break; | |
557 | } | |
558 | return NOTIFY_OK; | |
559 | } | |
560 | ||
561 | static struct notifier_block vtimer_idle_nb = { | |
562 | .notifier_call = vtimer_idle_notify, | |
563 | }; | |
564 | ||
565 | void __init vtime_init(void) | |
566 | { | |
567 | /* request the cpu timer external interrupt */ | |
568 | if (register_early_external_interrupt(0x1005, do_cpu_timer_interrupt, | |
569 | &ext_int_info_timer) != 0) | |
570 | panic("Couldn't request external interrupt 0x1005"); | |
571 | ||
572 | if (register_idle_notifier(&vtimer_idle_nb)) | |
573 | panic("Couldn't register idle notifier"); | |
574 | ||
575 | init_cpu_vtimer(); | |
576 | } | |
577 |