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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Virtual cpu timer based timer functions.
4 *
5 * Copyright IBM Corp. 2004, 2012
6 * Author(s): Jan Glauber <jan.glauber@de.ibm.com>
7 */
8
9#include <linux/kernel_stat.h>
10#include <linux/export.h>
11#include <linux/kernel.h>
12#include <linux/timex.h>
13#include <linux/types.h>
14#include <linux/time.h>
15#include <asm/alternative.h>
16#include <asm/cputime.h>
17#include <asm/vtimer.h>
18#include <asm/vtime.h>
19#include <asm/cpu_mf.h>
20#include <asm/smp.h>
21
22#include "entry.h"
23
24static void virt_timer_expire(void);
25
26static LIST_HEAD(virt_timer_list);
27static DEFINE_SPINLOCK(virt_timer_lock);
28static atomic64_t virt_timer_current;
29static atomic64_t virt_timer_elapsed;
30
31DEFINE_PER_CPU(u64, mt_cycles[8]);
32static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
33static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
34static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
35
36static inline u64 get_vtimer(void)
37{
38 u64 timer;
39
40 asm volatile("stpt %0" : "=Q" (timer));
41 return timer;
42}
43
44static inline void set_vtimer(u64 expires)
45{
46 u64 timer;
47
48 asm volatile(
49 " stpt %0\n" /* Store current cpu timer value */
50 " spt %1" /* Set new value imm. afterwards */
51 : "=Q" (timer) : "Q" (expires));
52 S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
53 S390_lowcore.last_update_timer = expires;
54}
55
56static inline int virt_timer_forward(u64 elapsed)
57{
58 BUG_ON(!irqs_disabled());
59
60 if (list_empty(&virt_timer_list))
61 return 0;
62 elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
63 return elapsed >= atomic64_read(&virt_timer_current);
64}
65
66static void update_mt_scaling(void)
67{
68 u64 cycles_new[8], *cycles_old;
69 u64 delta, fac, mult, div;
70 int i;
71
72 stcctm(MT_DIAG, smp_cpu_mtid + 1, cycles_new);
73 cycles_old = this_cpu_ptr(mt_cycles);
74 fac = 1;
75 mult = div = 0;
76 for (i = 0; i <= smp_cpu_mtid; i++) {
77 delta = cycles_new[i] - cycles_old[i];
78 div += delta;
79 mult *= i + 1;
80 mult += delta * fac;
81 fac *= i + 1;
82 }
83 div *= fac;
84 if (div > 0) {
85 /* Update scaling factor */
86 __this_cpu_write(mt_scaling_mult, mult);
87 __this_cpu_write(mt_scaling_div, div);
88 memcpy(cycles_old, cycles_new,
89 sizeof(u64) * (smp_cpu_mtid + 1));
90 }
91 __this_cpu_write(mt_scaling_jiffies, jiffies_64);
92}
93
94static inline u64 update_tsk_timer(unsigned long *tsk_vtime, u64 new)
95{
96 u64 delta;
97
98 delta = new - *tsk_vtime;
99 *tsk_vtime = new;
100 return delta;
101}
102
103
104static inline u64 scale_vtime(u64 vtime)
105{
106 u64 mult = __this_cpu_read(mt_scaling_mult);
107 u64 div = __this_cpu_read(mt_scaling_div);
108
109 if (smp_cpu_mtid)
110 return vtime * mult / div;
111 return vtime;
112}
113
114static void account_system_index_scaled(struct task_struct *p, u64 cputime,
115 enum cpu_usage_stat index)
116{
117 p->stimescaled += cputime_to_nsecs(scale_vtime(cputime));
118 account_system_index_time(p, cputime_to_nsecs(cputime), index);
119}
120
121/*
122 * Update process times based on virtual cpu times stored by entry.S
123 * to the lowcore fields user_timer, system_timer & steal_clock.
124 */
125static int do_account_vtime(struct task_struct *tsk)
126{
127 u64 timer, clock, user, guest, system, hardirq, softirq;
128
129 timer = S390_lowcore.last_update_timer;
130 clock = S390_lowcore.last_update_clock;
131 asm volatile(
132 " stpt %0\n" /* Store current cpu timer value */
133 " stckf %1" /* Store current tod clock value */
134 : "=Q" (S390_lowcore.last_update_timer),
135 "=Q" (S390_lowcore.last_update_clock)
136 : : "cc");
137 clock = S390_lowcore.last_update_clock - clock;
138 timer -= S390_lowcore.last_update_timer;
139
140 if (hardirq_count())
141 S390_lowcore.hardirq_timer += timer;
142 else
143 S390_lowcore.system_timer += timer;
144
145 /* Update MT utilization calculation */
146 if (smp_cpu_mtid &&
147 time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
148 update_mt_scaling();
149
150 /* Calculate cputime delta */
151 user = update_tsk_timer(&tsk->thread.user_timer,
152 READ_ONCE(S390_lowcore.user_timer));
153 guest = update_tsk_timer(&tsk->thread.guest_timer,
154 READ_ONCE(S390_lowcore.guest_timer));
155 system = update_tsk_timer(&tsk->thread.system_timer,
156 READ_ONCE(S390_lowcore.system_timer));
157 hardirq = update_tsk_timer(&tsk->thread.hardirq_timer,
158 READ_ONCE(S390_lowcore.hardirq_timer));
159 softirq = update_tsk_timer(&tsk->thread.softirq_timer,
160 READ_ONCE(S390_lowcore.softirq_timer));
161 S390_lowcore.steal_timer +=
162 clock - user - guest - system - hardirq - softirq;
163
164 /* Push account value */
165 if (user) {
166 account_user_time(tsk, cputime_to_nsecs(user));
167 tsk->utimescaled += cputime_to_nsecs(scale_vtime(user));
168 }
169
170 if (guest) {
171 account_guest_time(tsk, cputime_to_nsecs(guest));
172 tsk->utimescaled += cputime_to_nsecs(scale_vtime(guest));
173 }
174
175 if (system)
176 account_system_index_scaled(tsk, system, CPUTIME_SYSTEM);
177 if (hardirq)
178 account_system_index_scaled(tsk, hardirq, CPUTIME_IRQ);
179 if (softirq)
180 account_system_index_scaled(tsk, softirq, CPUTIME_SOFTIRQ);
181
182 return virt_timer_forward(user + guest + system + hardirq + softirq);
183}
184
185void vtime_task_switch(struct task_struct *prev)
186{
187 do_account_vtime(prev);
188 prev->thread.user_timer = S390_lowcore.user_timer;
189 prev->thread.guest_timer = S390_lowcore.guest_timer;
190 prev->thread.system_timer = S390_lowcore.system_timer;
191 prev->thread.hardirq_timer = S390_lowcore.hardirq_timer;
192 prev->thread.softirq_timer = S390_lowcore.softirq_timer;
193 S390_lowcore.user_timer = current->thread.user_timer;
194 S390_lowcore.guest_timer = current->thread.guest_timer;
195 S390_lowcore.system_timer = current->thread.system_timer;
196 S390_lowcore.hardirq_timer = current->thread.hardirq_timer;
197 S390_lowcore.softirq_timer = current->thread.softirq_timer;
198}
199
200/*
201 * In s390, accounting pending user time also implies
202 * accounting system time in order to correctly compute
203 * the stolen time accounting.
204 */
205void vtime_flush(struct task_struct *tsk)
206{
207 u64 steal, avg_steal;
208
209 if (do_account_vtime(tsk))
210 virt_timer_expire();
211
212 steal = S390_lowcore.steal_timer;
213 avg_steal = S390_lowcore.avg_steal_timer / 2;
214 if ((s64) steal > 0) {
215 S390_lowcore.steal_timer = 0;
216 account_steal_time(cputime_to_nsecs(steal));
217 avg_steal += steal;
218 }
219 S390_lowcore.avg_steal_timer = avg_steal;
220}
221
222static u64 vtime_delta(void)
223{
224 u64 timer = S390_lowcore.last_update_timer;
225
226 S390_lowcore.last_update_timer = get_vtimer();
227
228 return timer - S390_lowcore.last_update_timer;
229}
230
231/*
232 * Update process times based on virtual cpu times stored by entry.S
233 * to the lowcore fields user_timer, system_timer & steal_clock.
234 */
235void vtime_account_kernel(struct task_struct *tsk)
236{
237 u64 delta = vtime_delta();
238
239 if (tsk->flags & PF_VCPU)
240 S390_lowcore.guest_timer += delta;
241 else
242 S390_lowcore.system_timer += delta;
243
244 virt_timer_forward(delta);
245}
246EXPORT_SYMBOL_GPL(vtime_account_kernel);
247
248void vtime_account_softirq(struct task_struct *tsk)
249{
250 u64 delta = vtime_delta();
251
252 S390_lowcore.softirq_timer += delta;
253
254 virt_timer_forward(delta);
255}
256
257void vtime_account_hardirq(struct task_struct *tsk)
258{
259 u64 delta = vtime_delta();
260
261 S390_lowcore.hardirq_timer += delta;
262
263 virt_timer_forward(delta);
264}
265
266/*
267 * Sorted add to a list. List is linear searched until first bigger
268 * element is found.
269 */
270static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
271{
272 struct vtimer_list *tmp;
273
274 list_for_each_entry(tmp, head, entry) {
275 if (tmp->expires > timer->expires) {
276 list_add_tail(&timer->entry, &tmp->entry);
277 return;
278 }
279 }
280 list_add_tail(&timer->entry, head);
281}
282
283/*
284 * Handler for expired virtual CPU timer.
285 */
286static void virt_timer_expire(void)
287{
288 struct vtimer_list *timer, *tmp;
289 unsigned long elapsed;
290 LIST_HEAD(cb_list);
291
292 /* walk timer list, fire all expired timers */
293 spin_lock(&virt_timer_lock);
294 elapsed = atomic64_read(&virt_timer_elapsed);
295 list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
296 if (timer->expires < elapsed)
297 /* move expired timer to the callback queue */
298 list_move_tail(&timer->entry, &cb_list);
299 else
300 timer->expires -= elapsed;
301 }
302 if (!list_empty(&virt_timer_list)) {
303 timer = list_first_entry(&virt_timer_list,
304 struct vtimer_list, entry);
305 atomic64_set(&virt_timer_current, timer->expires);
306 }
307 atomic64_sub(elapsed, &virt_timer_elapsed);
308 spin_unlock(&virt_timer_lock);
309
310 /* Do callbacks and recharge periodic timers */
311 list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
312 list_del_init(&timer->entry);
313 timer->function(timer->data);
314 if (timer->interval) {
315 /* Recharge interval timer */
316 timer->expires = timer->interval +
317 atomic64_read(&virt_timer_elapsed);
318 spin_lock(&virt_timer_lock);
319 list_add_sorted(timer, &virt_timer_list);
320 spin_unlock(&virt_timer_lock);
321 }
322 }
323}
324
325void init_virt_timer(struct vtimer_list *timer)
326{
327 timer->function = NULL;
328 INIT_LIST_HEAD(&timer->entry);
329}
330EXPORT_SYMBOL(init_virt_timer);
331
332static inline int vtimer_pending(struct vtimer_list *timer)
333{
334 return !list_empty(&timer->entry);
335}
336
337static void internal_add_vtimer(struct vtimer_list *timer)
338{
339 if (list_empty(&virt_timer_list)) {
340 /* First timer, just program it. */
341 atomic64_set(&virt_timer_current, timer->expires);
342 atomic64_set(&virt_timer_elapsed, 0);
343 list_add(&timer->entry, &virt_timer_list);
344 } else {
345 /* Update timer against current base. */
346 timer->expires += atomic64_read(&virt_timer_elapsed);
347 if (likely((s64) timer->expires <
348 (s64) atomic64_read(&virt_timer_current)))
349 /* The new timer expires before the current timer. */
350 atomic64_set(&virt_timer_current, timer->expires);
351 /* Insert new timer into the list. */
352 list_add_sorted(timer, &virt_timer_list);
353 }
354}
355
356static void __add_vtimer(struct vtimer_list *timer, int periodic)
357{
358 unsigned long flags;
359
360 timer->interval = periodic ? timer->expires : 0;
361 spin_lock_irqsave(&virt_timer_lock, flags);
362 internal_add_vtimer(timer);
363 spin_unlock_irqrestore(&virt_timer_lock, flags);
364}
365
366/*
367 * add_virt_timer - add a oneshot virtual CPU timer
368 */
369void add_virt_timer(struct vtimer_list *timer)
370{
371 __add_vtimer(timer, 0);
372}
373EXPORT_SYMBOL(add_virt_timer);
374
375/*
376 * add_virt_timer_int - add an interval virtual CPU timer
377 */
378void add_virt_timer_periodic(struct vtimer_list *timer)
379{
380 __add_vtimer(timer, 1);
381}
382EXPORT_SYMBOL(add_virt_timer_periodic);
383
384static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
385{
386 unsigned long flags;
387 int rc;
388
389 BUG_ON(!timer->function);
390
391 if (timer->expires == expires && vtimer_pending(timer))
392 return 1;
393 spin_lock_irqsave(&virt_timer_lock, flags);
394 rc = vtimer_pending(timer);
395 if (rc)
396 list_del_init(&timer->entry);
397 timer->interval = periodic ? expires : 0;
398 timer->expires = expires;
399 internal_add_vtimer(timer);
400 spin_unlock_irqrestore(&virt_timer_lock, flags);
401 return rc;
402}
403
404/*
405 * returns whether it has modified a pending timer (1) or not (0)
406 */
407int mod_virt_timer(struct vtimer_list *timer, u64 expires)
408{
409 return __mod_vtimer(timer, expires, 0);
410}
411EXPORT_SYMBOL(mod_virt_timer);
412
413/*
414 * returns whether it has modified a pending timer (1) or not (0)
415 */
416int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
417{
418 return __mod_vtimer(timer, expires, 1);
419}
420EXPORT_SYMBOL(mod_virt_timer_periodic);
421
422/*
423 * Delete a virtual timer.
424 *
425 * returns whether the deleted timer was pending (1) or not (0)
426 */
427int del_virt_timer(struct vtimer_list *timer)
428{
429 unsigned long flags;
430
431 if (!vtimer_pending(timer))
432 return 0;
433 spin_lock_irqsave(&virt_timer_lock, flags);
434 list_del_init(&timer->entry);
435 spin_unlock_irqrestore(&virt_timer_lock, flags);
436 return 1;
437}
438EXPORT_SYMBOL(del_virt_timer);
439
440/*
441 * Start the virtual CPU timer on the current CPU.
442 */
443void vtime_init(void)
444{
445 /* set initial cpu timer */
446 set_vtimer(VTIMER_MAX_SLICE);
447 /* Setup initial MT scaling values */
448 if (smp_cpu_mtid) {
449 __this_cpu_write(mt_scaling_jiffies, jiffies);
450 __this_cpu_write(mt_scaling_mult, 1);
451 __this_cpu_write(mt_scaling_div, 1);
452 stcctm(MT_DIAG, smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
453 }
454}
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/notifier.h>
10#include <linux/kprobes.h>
11#include <linux/export.h>
12#include <linux/kernel.h>
13#include <linux/timex.h>
14#include <linux/types.h>
15#include <linux/time.h>
16#include <linux/cpu.h>
17#include <linux/smp.h>
18
19#include <asm/irq_regs.h>
20#include <asm/cputime.h>
21#include <asm/vtimer.h>
22#include <asm/vtime.h>
23#include <asm/irq.h>
24#include "entry.h"
25
26static void virt_timer_expire(void);
27
28DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
29
30static LIST_HEAD(virt_timer_list);
31static DEFINE_SPINLOCK(virt_timer_lock);
32static atomic64_t virt_timer_current;
33static atomic64_t virt_timer_elapsed;
34
35static inline u64 get_vtimer(void)
36{
37 u64 timer;
38
39 asm volatile("stpt %0" : "=m" (timer));
40 return timer;
41}
42
43static inline void set_vtimer(u64 expires)
44{
45 u64 timer;
46
47 asm volatile(
48 " stpt %0\n" /* Store current cpu timer value */
49 " spt %1" /* Set new value imm. afterwards */
50 : "=m" (timer) : "m" (expires));
51 S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
52 S390_lowcore.last_update_timer = expires;
53}
54
55static inline int virt_timer_forward(u64 elapsed)
56{
57 BUG_ON(!irqs_disabled());
58
59 if (list_empty(&virt_timer_list))
60 return 0;
61 elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
62 return elapsed >= atomic64_read(&virt_timer_current);
63}
64
65/*
66 * Update process times based on virtual cpu times stored by entry.S
67 * to the lowcore fields user_timer, system_timer & steal_clock.
68 */
69static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
70{
71 struct thread_info *ti = task_thread_info(tsk);
72 u64 timer, clock, user, system, steal;
73
74 timer = S390_lowcore.last_update_timer;
75 clock = S390_lowcore.last_update_clock;
76 asm volatile(
77 " stpt %0\n" /* Store current cpu timer value */
78 " stck %1" /* Store current tod clock value */
79 : "=m" (S390_lowcore.last_update_timer),
80 "=m" (S390_lowcore.last_update_clock));
81 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
82 S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
83
84 user = S390_lowcore.user_timer - ti->user_timer;
85 S390_lowcore.steal_timer -= user;
86 ti->user_timer = S390_lowcore.user_timer;
87 account_user_time(tsk, user, user);
88
89 system = S390_lowcore.system_timer - ti->system_timer;
90 S390_lowcore.steal_timer -= system;
91 ti->system_timer = S390_lowcore.system_timer;
92 account_system_time(tsk, hardirq_offset, system, system);
93
94 steal = S390_lowcore.steal_timer;
95 if ((s64) steal > 0) {
96 S390_lowcore.steal_timer = 0;
97 account_steal_time(steal);
98 }
99
100 return virt_timer_forward(user + system);
101}
102
103void vtime_task_switch(struct task_struct *prev)
104{
105 struct thread_info *ti;
106
107 do_account_vtime(prev, 0);
108 ti = task_thread_info(prev);
109 ti->user_timer = S390_lowcore.user_timer;
110 ti->system_timer = S390_lowcore.system_timer;
111 ti = task_thread_info(current);
112 S390_lowcore.user_timer = ti->user_timer;
113 S390_lowcore.system_timer = ti->system_timer;
114}
115
116/*
117 * In s390, accounting pending user time also implies
118 * accounting system time in order to correctly compute
119 * the stolen time accounting.
120 */
121void vtime_account_user(struct task_struct *tsk)
122{
123 if (do_account_vtime(tsk, HARDIRQ_OFFSET))
124 virt_timer_expire();
125}
126
127/*
128 * Update process times based on virtual cpu times stored by entry.S
129 * to the lowcore fields user_timer, system_timer & steal_clock.
130 */
131void vtime_account_irq_enter(struct task_struct *tsk)
132{
133 struct thread_info *ti = task_thread_info(tsk);
134 u64 timer, system;
135
136 WARN_ON_ONCE(!irqs_disabled());
137
138 timer = S390_lowcore.last_update_timer;
139 S390_lowcore.last_update_timer = get_vtimer();
140 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
141
142 system = S390_lowcore.system_timer - ti->system_timer;
143 S390_lowcore.steal_timer -= system;
144 ti->system_timer = S390_lowcore.system_timer;
145 account_system_time(tsk, 0, system, system);
146
147 virt_timer_forward(system);
148}
149EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
150
151void vtime_account_system(struct task_struct *tsk)
152__attribute__((alias("vtime_account_irq_enter")));
153EXPORT_SYMBOL_GPL(vtime_account_system);
154
155void __kprobes vtime_stop_cpu(void)
156{
157 struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
158 unsigned long long idle_time;
159 unsigned long psw_mask;
160
161 trace_hardirqs_on();
162
163 /* Wait for external, I/O or machine check interrupt. */
164 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
165 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
166 idle->nohz_delay = 0;
167
168 /* Call the assembler magic in entry.S */
169 psw_idle(idle, psw_mask);
170
171 /* Account time spent with enabled wait psw loaded as idle time. */
172 idle->sequence++;
173 smp_wmb();
174 idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
175 idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
176 idle->idle_time += idle_time;
177 idle->idle_count++;
178 account_idle_time(idle_time);
179 smp_wmb();
180 idle->sequence++;
181}
182
183cputime64_t s390_get_idle_time(int cpu)
184{
185 struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
186 unsigned long long now, idle_enter, idle_exit;
187 unsigned int sequence;
188
189 do {
190 now = get_tod_clock();
191 sequence = ACCESS_ONCE(idle->sequence);
192 idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
193 idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
194 } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
195 return idle_enter ? ((idle_exit ?: now) - idle_enter) : 0;
196}
197
198/*
199 * Sorted add to a list. List is linear searched until first bigger
200 * element is found.
201 */
202static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
203{
204 struct vtimer_list *tmp;
205
206 list_for_each_entry(tmp, head, entry) {
207 if (tmp->expires > timer->expires) {
208 list_add_tail(&timer->entry, &tmp->entry);
209 return;
210 }
211 }
212 list_add_tail(&timer->entry, head);
213}
214
215/*
216 * Handler for expired virtual CPU timer.
217 */
218static void virt_timer_expire(void)
219{
220 struct vtimer_list *timer, *tmp;
221 unsigned long elapsed;
222 LIST_HEAD(cb_list);
223
224 /* walk timer list, fire all expired timers */
225 spin_lock(&virt_timer_lock);
226 elapsed = atomic64_read(&virt_timer_elapsed);
227 list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
228 if (timer->expires < elapsed)
229 /* move expired timer to the callback queue */
230 list_move_tail(&timer->entry, &cb_list);
231 else
232 timer->expires -= elapsed;
233 }
234 if (!list_empty(&virt_timer_list)) {
235 timer = list_first_entry(&virt_timer_list,
236 struct vtimer_list, entry);
237 atomic64_set(&virt_timer_current, timer->expires);
238 }
239 atomic64_sub(elapsed, &virt_timer_elapsed);
240 spin_unlock(&virt_timer_lock);
241
242 /* Do callbacks and recharge periodic timers */
243 list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
244 list_del_init(&timer->entry);
245 timer->function(timer->data);
246 if (timer->interval) {
247 /* Recharge interval timer */
248 timer->expires = timer->interval +
249 atomic64_read(&virt_timer_elapsed);
250 spin_lock(&virt_timer_lock);
251 list_add_sorted(timer, &virt_timer_list);
252 spin_unlock(&virt_timer_lock);
253 }
254 }
255}
256
257void init_virt_timer(struct vtimer_list *timer)
258{
259 timer->function = NULL;
260 INIT_LIST_HEAD(&timer->entry);
261}
262EXPORT_SYMBOL(init_virt_timer);
263
264static inline int vtimer_pending(struct vtimer_list *timer)
265{
266 return !list_empty(&timer->entry);
267}
268
269static void internal_add_vtimer(struct vtimer_list *timer)
270{
271 if (list_empty(&virt_timer_list)) {
272 /* First timer, just program it. */
273 atomic64_set(&virt_timer_current, timer->expires);
274 atomic64_set(&virt_timer_elapsed, 0);
275 list_add(&timer->entry, &virt_timer_list);
276 } else {
277 /* Update timer against current base. */
278 timer->expires += atomic64_read(&virt_timer_elapsed);
279 if (likely((s64) timer->expires <
280 (s64) atomic64_read(&virt_timer_current)))
281 /* The new timer expires before the current timer. */
282 atomic64_set(&virt_timer_current, timer->expires);
283 /* Insert new timer into the list. */
284 list_add_sorted(timer, &virt_timer_list);
285 }
286}
287
288static void __add_vtimer(struct vtimer_list *timer, int periodic)
289{
290 unsigned long flags;
291
292 timer->interval = periodic ? timer->expires : 0;
293 spin_lock_irqsave(&virt_timer_lock, flags);
294 internal_add_vtimer(timer);
295 spin_unlock_irqrestore(&virt_timer_lock, flags);
296}
297
298/*
299 * add_virt_timer - add an oneshot virtual CPU timer
300 */
301void add_virt_timer(struct vtimer_list *timer)
302{
303 __add_vtimer(timer, 0);
304}
305EXPORT_SYMBOL(add_virt_timer);
306
307/*
308 * add_virt_timer_int - add an interval virtual CPU timer
309 */
310void add_virt_timer_periodic(struct vtimer_list *timer)
311{
312 __add_vtimer(timer, 1);
313}
314EXPORT_SYMBOL(add_virt_timer_periodic);
315
316static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
317{
318 unsigned long flags;
319 int rc;
320
321 BUG_ON(!timer->function);
322
323 if (timer->expires == expires && vtimer_pending(timer))
324 return 1;
325 spin_lock_irqsave(&virt_timer_lock, flags);
326 rc = vtimer_pending(timer);
327 if (rc)
328 list_del_init(&timer->entry);
329 timer->interval = periodic ? expires : 0;
330 timer->expires = expires;
331 internal_add_vtimer(timer);
332 spin_unlock_irqrestore(&virt_timer_lock, flags);
333 return rc;
334}
335
336/*
337 * returns whether it has modified a pending timer (1) or not (0)
338 */
339int mod_virt_timer(struct vtimer_list *timer, u64 expires)
340{
341 return __mod_vtimer(timer, expires, 0);
342}
343EXPORT_SYMBOL(mod_virt_timer);
344
345/*
346 * returns whether it has modified a pending timer (1) or not (0)
347 */
348int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
349{
350 return __mod_vtimer(timer, expires, 1);
351}
352EXPORT_SYMBOL(mod_virt_timer_periodic);
353
354/*
355 * Delete a virtual timer.
356 *
357 * returns whether the deleted timer was pending (1) or not (0)
358 */
359int del_virt_timer(struct vtimer_list *timer)
360{
361 unsigned long flags;
362
363 if (!vtimer_pending(timer))
364 return 0;
365 spin_lock_irqsave(&virt_timer_lock, flags);
366 list_del_init(&timer->entry);
367 spin_unlock_irqrestore(&virt_timer_lock, flags);
368 return 1;
369}
370EXPORT_SYMBOL(del_virt_timer);
371
372/*
373 * Start the virtual CPU timer on the current CPU.
374 */
375void init_cpu_vtimer(void)
376{
377 /* set initial cpu timer */
378 set_vtimer(VTIMER_MAX_SLICE);
379}
380
381static int s390_nohz_notify(struct notifier_block *self, unsigned long action,
382 void *hcpu)
383{
384 struct s390_idle_data *idle;
385 long cpu = (long) hcpu;
386
387 idle = &per_cpu(s390_idle, cpu);
388 switch (action & ~CPU_TASKS_FROZEN) {
389 case CPU_DYING:
390 idle->nohz_delay = 0;
391 default:
392 break;
393 }
394 return NOTIFY_OK;
395}
396
397void __init vtime_init(void)
398{
399 /* Enable cpu timer interrupts on the boot cpu. */
400 init_cpu_vtimer();
401 cpu_notifier(s390_nohz_notify, 0);
402}