Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Virtual cpu timer based timer functions. |
3 | * | |
27f6b416 | 4 | * Copyright IBM Corp. 2004, 2012 |
1da177e4 LT |
5 | * Author(s): Jan Glauber <jan.glauber@de.ibm.com> |
6 | */ | |
7 | ||
27f6b416 | 8 | #include <linux/kernel_stat.h> |
27f6b416 | 9 | #include <linux/export.h> |
1da177e4 | 10 | #include <linux/kernel.h> |
1da177e4 | 11 | #include <linux/timex.h> |
27f6b416 MS |
12 | #include <linux/types.h> |
13 | #include <linux/time.h> | |
1da177e4 | 14 | |
76d4e00a | 15 | #include <asm/cputime.h> |
27f6b416 | 16 | #include <asm/vtimer.h> |
a5725ac2 | 17 | #include <asm/vtime.h> |
1da177e4 | 18 | |
27f6b416 | 19 | static void virt_timer_expire(void); |
1da177e4 | 20 | |
27f6b416 MS |
21 | static LIST_HEAD(virt_timer_list); |
22 | static DEFINE_SPINLOCK(virt_timer_lock); | |
23 | static atomic64_t virt_timer_current; | |
24 | static atomic64_t virt_timer_elapsed; | |
25 | ||
26 | static inline u64 get_vtimer(void) | |
9cfb9b3c | 27 | { |
27f6b416 | 28 | u64 timer; |
9cfb9b3c | 29 | |
27f6b416 | 30 | asm volatile("stpt %0" : "=m" (timer)); |
9cfb9b3c MS |
31 | return timer; |
32 | } | |
33 | ||
27f6b416 | 34 | static inline void set_vtimer(u64 expires) |
9cfb9b3c | 35 | { |
27f6b416 | 36 | u64 timer; |
9cfb9b3c | 37 | |
27f6b416 MS |
38 | asm volatile( |
39 | " stpt %0\n" /* Store current cpu timer value */ | |
40 | " spt %1" /* Set new value imm. afterwards */ | |
41 | : "=m" (timer) : "m" (expires)); | |
9cfb9b3c MS |
42 | S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer; |
43 | S390_lowcore.last_update_timer = expires; | |
44 | } | |
45 | ||
27f6b416 MS |
46 | static inline int virt_timer_forward(u64 elapsed) |
47 | { | |
48 | BUG_ON(!irqs_disabled()); | |
49 | ||
50 | if (list_empty(&virt_timer_list)) | |
51 | return 0; | |
52 | elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed); | |
53 | return elapsed >= atomic64_read(&virt_timer_current); | |
54 | } | |
55 | ||
1da177e4 LT |
56 | /* |
57 | * Update process times based on virtual cpu times stored by entry.S | |
58 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
59 | */ | |
27f6b416 | 60 | static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) |
1da177e4 | 61 | { |
aa5e97ce | 62 | struct thread_info *ti = task_thread_info(tsk); |
27f6b416 | 63 | u64 timer, clock, user, system, steal; |
1da177e4 LT |
64 | |
65 | timer = S390_lowcore.last_update_timer; | |
66 | clock = S390_lowcore.last_update_clock; | |
27f6b416 MS |
67 | asm volatile( |
68 | " stpt %0\n" /* Store current cpu timer value */ | |
1f759bb3 MS |
69 | #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES |
70 | " stckf %1" /* Store current tod clock value */ | |
71 | #else | |
27f6b416 | 72 | " stck %1" /* Store current tod clock value */ |
1f759bb3 | 73 | #endif |
27f6b416 MS |
74 | : "=m" (S390_lowcore.last_update_timer), |
75 | "=m" (S390_lowcore.last_update_clock)); | |
1da177e4 | 76 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; |
aa5e97ce | 77 | S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock; |
1da177e4 | 78 | |
aa5e97ce MS |
79 | user = S390_lowcore.user_timer - ti->user_timer; |
80 | S390_lowcore.steal_timer -= user; | |
81 | ti->user_timer = S390_lowcore.user_timer; | |
82 | account_user_time(tsk, user, user); | |
1da177e4 | 83 | |
aa5e97ce MS |
84 | system = S390_lowcore.system_timer - ti->system_timer; |
85 | S390_lowcore.steal_timer -= system; | |
86 | ti->system_timer = S390_lowcore.system_timer; | |
9cfb9b3c | 87 | account_system_time(tsk, hardirq_offset, system, system); |
1da177e4 | 88 | |
aa5e97ce MS |
89 | steal = S390_lowcore.steal_timer; |
90 | if ((s64) steal > 0) { | |
91 | S390_lowcore.steal_timer = 0; | |
9cfb9b3c | 92 | account_steal_time(steal); |
1da177e4 | 93 | } |
27f6b416 MS |
94 | |
95 | return virt_timer_forward(user + system); | |
1da177e4 LT |
96 | } |
97 | ||
bf9fae9f | 98 | void vtime_task_switch(struct task_struct *prev) |
1f1c12af | 99 | { |
aa5e97ce MS |
100 | struct thread_info *ti; |
101 | ||
102 | do_account_vtime(prev, 0); | |
103 | ti = task_thread_info(prev); | |
104 | ti->user_timer = S390_lowcore.user_timer; | |
105 | ti->system_timer = S390_lowcore.system_timer; | |
baa36046 | 106 | ti = task_thread_info(current); |
aa5e97ce MS |
107 | S390_lowcore.user_timer = ti->user_timer; |
108 | S390_lowcore.system_timer = ti->system_timer; | |
109 | } | |
1f1c12af | 110 | |
bcebdf84 FW |
111 | /* |
112 | * In s390, accounting pending user time also implies | |
113 | * accounting system time in order to correctly compute | |
114 | * the stolen time accounting. | |
115 | */ | |
116 | void vtime_account_user(struct task_struct *tsk) | |
aa5e97ce | 117 | { |
27f6b416 MS |
118 | if (do_account_vtime(tsk, HARDIRQ_OFFSET)) |
119 | virt_timer_expire(); | |
1f1c12af MS |
120 | } |
121 | ||
1da177e4 LT |
122 | /* |
123 | * Update process times based on virtual cpu times stored by entry.S | |
124 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
125 | */ | |
6a61671b | 126 | void vtime_account_irq_enter(struct task_struct *tsk) |
1da177e4 | 127 | { |
aa5e97ce | 128 | struct thread_info *ti = task_thread_info(tsk); |
27f6b416 | 129 | u64 timer, system; |
1da177e4 | 130 | |
1b2852b1 FW |
131 | WARN_ON_ONCE(!irqs_disabled()); |
132 | ||
1da177e4 | 133 | timer = S390_lowcore.last_update_timer; |
9cfb9b3c | 134 | S390_lowcore.last_update_timer = get_vtimer(); |
1da177e4 LT |
135 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; |
136 | ||
aa5e97ce MS |
137 | system = S390_lowcore.system_timer - ti->system_timer; |
138 | S390_lowcore.steal_timer -= system; | |
139 | ti->system_timer = S390_lowcore.system_timer; | |
9cfb9b3c | 140 | account_system_time(tsk, 0, system, system); |
27f6b416 MS |
141 | |
142 | virt_timer_forward(system); | |
1da177e4 | 143 | } |
6a61671b | 144 | EXPORT_SYMBOL_GPL(vtime_account_irq_enter); |
1da177e4 | 145 | |
fd25b4c2 | 146 | void vtime_account_system(struct task_struct *tsk) |
6a61671b | 147 | __attribute__((alias("vtime_account_irq_enter"))); |
fd25b4c2 | 148 | EXPORT_SYMBOL_GPL(vtime_account_system); |
11113334 | 149 | |
1da177e4 LT |
150 | /* |
151 | * Sorted add to a list. List is linear searched until first bigger | |
152 | * element is found. | |
153 | */ | |
154 | static void list_add_sorted(struct vtimer_list *timer, struct list_head *head) | |
155 | { | |
27f6b416 | 156 | struct vtimer_list *tmp; |
1da177e4 | 157 | |
27f6b416 MS |
158 | list_for_each_entry(tmp, head, entry) { |
159 | if (tmp->expires > timer->expires) { | |
160 | list_add_tail(&timer->entry, &tmp->entry); | |
1da177e4 LT |
161 | return; |
162 | } | |
163 | } | |
164 | list_add_tail(&timer->entry, head); | |
165 | } | |
166 | ||
167 | /* | |
27f6b416 | 168 | * Handler for expired virtual CPU timer. |
1da177e4 | 169 | */ |
27f6b416 | 170 | static void virt_timer_expire(void) |
1da177e4 | 171 | { |
27f6b416 MS |
172 | struct vtimer_list *timer, *tmp; |
173 | unsigned long elapsed; | |
174 | LIST_HEAD(cb_list); | |
175 | ||
176 | /* walk timer list, fire all expired timers */ | |
177 | spin_lock(&virt_timer_lock); | |
178 | elapsed = atomic64_read(&virt_timer_elapsed); | |
179 | list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) { | |
180 | if (timer->expires < elapsed) | |
9cfb9b3c | 181 | /* move expired timer to the callback queue */ |
27f6b416 | 182 | list_move_tail(&timer->entry, &cb_list); |
9cfb9b3c | 183 | else |
27f6b416 | 184 | timer->expires -= elapsed; |
1da177e4 | 185 | } |
27f6b416 MS |
186 | if (!list_empty(&virt_timer_list)) { |
187 | timer = list_first_entry(&virt_timer_list, | |
188 | struct vtimer_list, entry); | |
189 | atomic64_set(&virt_timer_current, timer->expires); | |
190 | } | |
191 | atomic64_sub(elapsed, &virt_timer_elapsed); | |
192 | spin_unlock(&virt_timer_lock); | |
193 | ||
194 | /* Do callbacks and recharge periodic timers */ | |
195 | list_for_each_entry_safe(timer, tmp, &cb_list, entry) { | |
196 | list_del_init(&timer->entry); | |
197 | timer->function(timer->data); | |
198 | if (timer->interval) { | |
199 | /* Recharge interval timer */ | |
200 | timer->expires = timer->interval + | |
201 | atomic64_read(&virt_timer_elapsed); | |
202 | spin_lock(&virt_timer_lock); | |
203 | list_add_sorted(timer, &virt_timer_list); | |
204 | spin_unlock(&virt_timer_lock); | |
205 | } | |
4c1051e3 | 206 | } |
1da177e4 LT |
207 | } |
208 | ||
209 | void init_virt_timer(struct vtimer_list *timer) | |
210 | { | |
1da177e4 LT |
211 | timer->function = NULL; |
212 | INIT_LIST_HEAD(&timer->entry); | |
1da177e4 LT |
213 | } |
214 | EXPORT_SYMBOL(init_virt_timer); | |
215 | ||
1da177e4 LT |
216 | static inline int vtimer_pending(struct vtimer_list *timer) |
217 | { | |
27f6b416 | 218 | return !list_empty(&timer->entry); |
1da177e4 LT |
219 | } |
220 | ||
1da177e4 LT |
221 | static void internal_add_vtimer(struct vtimer_list *timer) |
222 | { | |
27f6b416 MS |
223 | if (list_empty(&virt_timer_list)) { |
224 | /* First timer, just program it. */ | |
225 | atomic64_set(&virt_timer_current, timer->expires); | |
226 | atomic64_set(&virt_timer_elapsed, 0); | |
227 | list_add(&timer->entry, &virt_timer_list); | |
9cfb9b3c | 228 | } else { |
27f6b416 MS |
229 | /* Update timer against current base. */ |
230 | timer->expires += atomic64_read(&virt_timer_elapsed); | |
231 | if (likely((s64) timer->expires < | |
232 | (s64) atomic64_read(&virt_timer_current))) | |
9cfb9b3c | 233 | /* The new timer expires before the current timer. */ |
27f6b416 MS |
234 | atomic64_set(&virt_timer_current, timer->expires); |
235 | /* Insert new timer into the list. */ | |
236 | list_add_sorted(timer, &virt_timer_list); | |
1da177e4 | 237 | } |
1da177e4 LT |
238 | } |
239 | ||
27f6b416 | 240 | static void __add_vtimer(struct vtimer_list *timer, int periodic) |
1da177e4 | 241 | { |
27f6b416 MS |
242 | unsigned long flags; |
243 | ||
244 | timer->interval = periodic ? timer->expires : 0; | |
245 | spin_lock_irqsave(&virt_timer_lock, flags); | |
246 | internal_add_vtimer(timer); | |
247 | spin_unlock_irqrestore(&virt_timer_lock, flags); | |
1da177e4 LT |
248 | } |
249 | ||
250 | /* | |
251 | * add_virt_timer - add an oneshot virtual CPU timer | |
252 | */ | |
27f6b416 | 253 | void add_virt_timer(struct vtimer_list *timer) |
1da177e4 | 254 | { |
27f6b416 | 255 | __add_vtimer(timer, 0); |
1da177e4 LT |
256 | } |
257 | EXPORT_SYMBOL(add_virt_timer); | |
258 | ||
259 | /* | |
260 | * add_virt_timer_int - add an interval virtual CPU timer | |
261 | */ | |
27f6b416 | 262 | void add_virt_timer_periodic(struct vtimer_list *timer) |
1da177e4 | 263 | { |
27f6b416 | 264 | __add_vtimer(timer, 1); |
1da177e4 LT |
265 | } |
266 | EXPORT_SYMBOL(add_virt_timer_periodic); | |
267 | ||
27f6b416 | 268 | static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic) |
1da177e4 | 269 | { |
1da177e4 | 270 | unsigned long flags; |
27f6b416 | 271 | int rc; |
1da177e4 | 272 | |
ca366a32 | 273 | BUG_ON(!timer->function); |
1da177e4 | 274 | |
1da177e4 LT |
275 | if (timer->expires == expires && vtimer_pending(timer)) |
276 | return 1; | |
27f6b416 MS |
277 | spin_lock_irqsave(&virt_timer_lock, flags); |
278 | rc = vtimer_pending(timer); | |
279 | if (rc) | |
280 | list_del_init(&timer->entry); | |
281 | timer->interval = periodic ? expires : 0; | |
1da177e4 | 282 | timer->expires = expires; |
1da177e4 | 283 | internal_add_vtimer(timer); |
27f6b416 MS |
284 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
285 | return rc; | |
1da177e4 | 286 | } |
b6ecfa92 JG |
287 | |
288 | /* | |
b6ecfa92 JG |
289 | * returns whether it has modified a pending timer (1) or not (0) |
290 | */ | |
27f6b416 | 291 | int mod_virt_timer(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
292 | { |
293 | return __mod_vtimer(timer, expires, 0); | |
294 | } | |
1da177e4 LT |
295 | EXPORT_SYMBOL(mod_virt_timer); |
296 | ||
b6ecfa92 | 297 | /* |
b6ecfa92 JG |
298 | * returns whether it has modified a pending timer (1) or not (0) |
299 | */ | |
27f6b416 | 300 | int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
301 | { |
302 | return __mod_vtimer(timer, expires, 1); | |
303 | } | |
304 | EXPORT_SYMBOL(mod_virt_timer_periodic); | |
305 | ||
1da177e4 | 306 | /* |
27f6b416 | 307 | * Delete a virtual timer. |
1da177e4 LT |
308 | * |
309 | * returns whether the deleted timer was pending (1) or not (0) | |
310 | */ | |
311 | int del_virt_timer(struct vtimer_list *timer) | |
312 | { | |
313 | unsigned long flags; | |
1da177e4 | 314 | |
1da177e4 LT |
315 | if (!vtimer_pending(timer)) |
316 | return 0; | |
27f6b416 | 317 | spin_lock_irqsave(&virt_timer_lock, flags); |
1da177e4 | 318 | list_del_init(&timer->entry); |
27f6b416 | 319 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
1da177e4 LT |
320 | return 1; |
321 | } | |
322 | EXPORT_SYMBOL(del_virt_timer); | |
323 | ||
324 | /* | |
325 | * Start the virtual CPU timer on the current CPU. | |
326 | */ | |
b5f87f15 | 327 | void vtime_init(void) |
1da177e4 | 328 | { |
8b646bd7 | 329 | /* set initial cpu timer */ |
27f6b416 | 330 | set_vtimer(VTIMER_MAX_SLICE); |
1da177e4 | 331 | } |