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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
21#include "entry.h"
22
23static void virt_timer_expire(void);
24
25static LIST_HEAD(virt_timer_list);
26static DEFINE_SPINLOCK(virt_timer_lock);
27static atomic64_t virt_timer_current;
28static atomic64_t virt_timer_elapsed;
29
30DEFINE_PER_CPU(u64, mt_cycles[8]);
31static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
32static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
33static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
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
65static void update_mt_scaling(void)
66{
67 u64 cycles_new[8], *cycles_old;
68 u64 delta, fac, mult, div;
69 int i;
70
71 stcctm5(smp_cpu_mtid + 1, cycles_new);
72 cycles_old = this_cpu_ptr(mt_cycles);
73 fac = 1;
74 mult = div = 0;
75 for (i = 0; i <= smp_cpu_mtid; i++) {
76 delta = cycles_new[i] - cycles_old[i];
77 div += delta;
78 mult *= i + 1;
79 mult += delta * fac;
80 fac *= i + 1;
81 }
82 div *= fac;
83 if (div > 0) {
84 /* Update scaling factor */
85 __this_cpu_write(mt_scaling_mult, mult);
86 __this_cpu_write(mt_scaling_div, div);
87 memcpy(cycles_old, cycles_new,
88 sizeof(u64) * (smp_cpu_mtid + 1));
89 }
90 __this_cpu_write(mt_scaling_jiffies, jiffies_64);
91}
92
93/*
94 * Update process times based on virtual cpu times stored by entry.S
95 * to the lowcore fields user_timer, system_timer & steal_clock.
96 */
97static int do_account_vtime(struct task_struct *tsk)
98{
99 u64 timer, clock, user, system, steal;
100 u64 user_scaled, system_scaled;
101
102 timer = S390_lowcore.last_update_timer;
103 clock = S390_lowcore.last_update_clock;
104 asm volatile(
105 " stpt %0\n" /* Store current cpu timer value */
106#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
107 " stckf %1" /* Store current tod clock value */
108#else
109 " stck %1" /* Store current tod clock value */
110#endif
111 : "=m" (S390_lowcore.last_update_timer),
112 "=m" (S390_lowcore.last_update_clock));
113 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
114 S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
115
116 /* Update MT utilization calculation */
117 if (smp_cpu_mtid &&
118 time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
119 update_mt_scaling();
120
121 user = S390_lowcore.user_timer - tsk->thread.user_timer;
122 S390_lowcore.steal_timer -= user;
123 tsk->thread.user_timer = S390_lowcore.user_timer;
124
125 system = S390_lowcore.system_timer - tsk->thread.system_timer;
126 S390_lowcore.steal_timer -= system;
127 tsk->thread.system_timer = S390_lowcore.system_timer;
128
129 user_scaled = user;
130 system_scaled = system;
131 /* Do MT utilization scaling */
132 if (smp_cpu_mtid) {
133 u64 mult = __this_cpu_read(mt_scaling_mult);
134 u64 div = __this_cpu_read(mt_scaling_div);
135
136 user_scaled = (user_scaled * mult) / div;
137 system_scaled = (system_scaled * mult) / div;
138 }
139 account_user_time(tsk, user);
140 tsk->utimescaled += user_scaled;
141 account_system_time(tsk, 0, system);
142 tsk->stimescaled += system_scaled;
143
144 steal = S390_lowcore.steal_timer;
145 if ((s64) steal > 0) {
146 S390_lowcore.steal_timer = 0;
147 account_steal_time(steal);
148 }
149
150 return virt_timer_forward(user + system);
151}
152
153void vtime_task_switch(struct task_struct *prev)
154{
155 do_account_vtime(prev);
156 prev->thread.user_timer = S390_lowcore.user_timer;
157 prev->thread.system_timer = S390_lowcore.system_timer;
158 S390_lowcore.user_timer = current->thread.user_timer;
159 S390_lowcore.system_timer = current->thread.system_timer;
160}
161
162/*
163 * In s390, accounting pending user time also implies
164 * accounting system time in order to correctly compute
165 * the stolen time accounting.
166 */
167void vtime_account_user(struct task_struct *tsk)
168{
169 if (do_account_vtime(tsk))
170 virt_timer_expire();
171}
172
173/*
174 * Update process times based on virtual cpu times stored by entry.S
175 * to the lowcore fields user_timer, system_timer & steal_clock.
176 */
177void vtime_account_irq_enter(struct task_struct *tsk)
178{
179 u64 timer, system, system_scaled;
180
181 timer = S390_lowcore.last_update_timer;
182 S390_lowcore.last_update_timer = get_vtimer();
183 S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
184
185 /* Update MT utilization calculation */
186 if (smp_cpu_mtid &&
187 time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
188 update_mt_scaling();
189
190 system = S390_lowcore.system_timer - tsk->thread.system_timer;
191 S390_lowcore.steal_timer -= system;
192 tsk->thread.system_timer = S390_lowcore.system_timer;
193 system_scaled = system;
194 /* Do MT utilization scaling */
195 if (smp_cpu_mtid) {
196 u64 mult = __this_cpu_read(mt_scaling_mult);
197 u64 div = __this_cpu_read(mt_scaling_div);
198
199 system_scaled = (system_scaled * mult) / div;
200 }
201 account_system_time(tsk, 0, system);
202 tsk->stimescaled += system_scaled;
203
204 virt_timer_forward(system);
205}
206EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
207
208void vtime_account_system(struct task_struct *tsk)
209__attribute__((alias("vtime_account_irq_enter")));
210EXPORT_SYMBOL_GPL(vtime_account_system);
211
212/*
213 * Sorted add to a list. List is linear searched until first bigger
214 * element is found.
215 */
216static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
217{
218 struct vtimer_list *tmp;
219
220 list_for_each_entry(tmp, head, entry) {
221 if (tmp->expires > timer->expires) {
222 list_add_tail(&timer->entry, &tmp->entry);
223 return;
224 }
225 }
226 list_add_tail(&timer->entry, head);
227}
228
229/*
230 * Handler for expired virtual CPU timer.
231 */
232static void virt_timer_expire(void)
233{
234 struct vtimer_list *timer, *tmp;
235 unsigned long elapsed;
236 LIST_HEAD(cb_list);
237
238 /* walk timer list, fire all expired timers */
239 spin_lock(&virt_timer_lock);
240 elapsed = atomic64_read(&virt_timer_elapsed);
241 list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
242 if (timer->expires < elapsed)
243 /* move expired timer to the callback queue */
244 list_move_tail(&timer->entry, &cb_list);
245 else
246 timer->expires -= elapsed;
247 }
248 if (!list_empty(&virt_timer_list)) {
249 timer = list_first_entry(&virt_timer_list,
250 struct vtimer_list, entry);
251 atomic64_set(&virt_timer_current, timer->expires);
252 }
253 atomic64_sub(elapsed, &virt_timer_elapsed);
254 spin_unlock(&virt_timer_lock);
255
256 /* Do callbacks and recharge periodic timers */
257 list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
258 list_del_init(&timer->entry);
259 timer->function(timer->data);
260 if (timer->interval) {
261 /* Recharge interval timer */
262 timer->expires = timer->interval +
263 atomic64_read(&virt_timer_elapsed);
264 spin_lock(&virt_timer_lock);
265 list_add_sorted(timer, &virt_timer_list);
266 spin_unlock(&virt_timer_lock);
267 }
268 }
269}
270
271void init_virt_timer(struct vtimer_list *timer)
272{
273 timer->function = NULL;
274 INIT_LIST_HEAD(&timer->entry);
275}
276EXPORT_SYMBOL(init_virt_timer);
277
278static inline int vtimer_pending(struct vtimer_list *timer)
279{
280 return !list_empty(&timer->entry);
281}
282
283static void internal_add_vtimer(struct vtimer_list *timer)
284{
285 if (list_empty(&virt_timer_list)) {
286 /* First timer, just program it. */
287 atomic64_set(&virt_timer_current, timer->expires);
288 atomic64_set(&virt_timer_elapsed, 0);
289 list_add(&timer->entry, &virt_timer_list);
290 } else {
291 /* Update timer against current base. */
292 timer->expires += atomic64_read(&virt_timer_elapsed);
293 if (likely((s64) timer->expires <
294 (s64) atomic64_read(&virt_timer_current)))
295 /* The new timer expires before the current timer. */
296 atomic64_set(&virt_timer_current, timer->expires);
297 /* Insert new timer into the list. */
298 list_add_sorted(timer, &virt_timer_list);
299 }
300}
301
302static void __add_vtimer(struct vtimer_list *timer, int periodic)
303{
304 unsigned long flags;
305
306 timer->interval = periodic ? timer->expires : 0;
307 spin_lock_irqsave(&virt_timer_lock, flags);
308 internal_add_vtimer(timer);
309 spin_unlock_irqrestore(&virt_timer_lock, flags);
310}
311
312/*
313 * add_virt_timer - add an oneshot virtual CPU timer
314 */
315void add_virt_timer(struct vtimer_list *timer)
316{
317 __add_vtimer(timer, 0);
318}
319EXPORT_SYMBOL(add_virt_timer);
320
321/*
322 * add_virt_timer_int - add an interval virtual CPU timer
323 */
324void add_virt_timer_periodic(struct vtimer_list *timer)
325{
326 __add_vtimer(timer, 1);
327}
328EXPORT_SYMBOL(add_virt_timer_periodic);
329
330static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
331{
332 unsigned long flags;
333 int rc;
334
335 BUG_ON(!timer->function);
336
337 if (timer->expires == expires && vtimer_pending(timer))
338 return 1;
339 spin_lock_irqsave(&virt_timer_lock, flags);
340 rc = vtimer_pending(timer);
341 if (rc)
342 list_del_init(&timer->entry);
343 timer->interval = periodic ? expires : 0;
344 timer->expires = expires;
345 internal_add_vtimer(timer);
346 spin_unlock_irqrestore(&virt_timer_lock, flags);
347 return rc;
348}
349
350/*
351 * returns whether it has modified a pending timer (1) or not (0)
352 */
353int mod_virt_timer(struct vtimer_list *timer, u64 expires)
354{
355 return __mod_vtimer(timer, expires, 0);
356}
357EXPORT_SYMBOL(mod_virt_timer);
358
359/*
360 * returns whether it has modified a pending timer (1) or not (0)
361 */
362int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
363{
364 return __mod_vtimer(timer, expires, 1);
365}
366EXPORT_SYMBOL(mod_virt_timer_periodic);
367
368/*
369 * Delete a virtual timer.
370 *
371 * returns whether the deleted timer was pending (1) or not (0)
372 */
373int del_virt_timer(struct vtimer_list *timer)
374{
375 unsigned long flags;
376
377 if (!vtimer_pending(timer))
378 return 0;
379 spin_lock_irqsave(&virt_timer_lock, flags);
380 list_del_init(&timer->entry);
381 spin_unlock_irqrestore(&virt_timer_lock, flags);
382 return 1;
383}
384EXPORT_SYMBOL(del_virt_timer);
385
386/*
387 * Start the virtual CPU timer on the current CPU.
388 */
389void vtime_init(void)
390{
391 /* set initial cpu timer */
392 set_vtimer(VTIMER_MAX_SLICE);
393 /* Setup initial MT scaling values */
394 if (smp_cpu_mtid) {
395 __this_cpu_write(mt_scaling_jiffies, jiffies);
396 __this_cpu_write(mt_scaling_mult, 1);
397 __this_cpu_write(mt_scaling_div, 1);
398 stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
399 }
400}
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}