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a17ae4c3 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * Virtual cpu timer based timer functions. |
4 | * | |
27f6b416 | 5 | * Copyright IBM Corp. 2004, 2012 |
1da177e4 LT |
6 | * Author(s): Jan Glauber <jan.glauber@de.ibm.com> |
7 | */ | |
8 | ||
27f6b416 | 9 | #include <linux/kernel_stat.h> |
32ef5517 | 10 | #include <linux/sched/cputime.h> |
27f6b416 | 11 | #include <linux/export.h> |
1da177e4 | 12 | #include <linux/kernel.h> |
1da177e4 | 13 | #include <linux/timex.h> |
27f6b416 MS |
14 | #include <linux/types.h> |
15 | #include <linux/time.h> | |
1da177e4 | 16 | |
27f6b416 | 17 | #include <asm/vtimer.h> |
a5725ac2 | 18 | #include <asm/vtime.h> |
10ad34bc MS |
19 | #include <asm/cpu_mf.h> |
20 | #include <asm/smp.h> | |
1da177e4 | 21 | |
521b00cd HC |
22 | #include "entry.h" |
23 | ||
27f6b416 | 24 | static void virt_timer_expire(void); |
1da177e4 | 25 | |
27f6b416 MS |
26 | static LIST_HEAD(virt_timer_list); |
27 | static DEFINE_SPINLOCK(virt_timer_lock); | |
28 | static atomic64_t virt_timer_current; | |
29 | static atomic64_t virt_timer_elapsed; | |
30 | ||
72d38b19 | 31 | DEFINE_PER_CPU(u64, mt_cycles[8]); |
10ad34bc MS |
32 | static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 }; |
33 | static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 }; | |
f341b8df | 34 | static DEFINE_PER_CPU(u64, mt_scaling_jiffies); |
10ad34bc | 35 | |
27f6b416 | 36 | static inline u64 get_vtimer(void) |
9cfb9b3c | 37 | { |
27f6b416 | 38 | u64 timer; |
9cfb9b3c | 39 | |
27f6b416 | 40 | asm volatile("stpt %0" : "=m" (timer)); |
9cfb9b3c MS |
41 | return timer; |
42 | } | |
43 | ||
27f6b416 | 44 | static inline void set_vtimer(u64 expires) |
9cfb9b3c | 45 | { |
27f6b416 | 46 | u64 timer; |
9cfb9b3c | 47 | |
27f6b416 MS |
48 | asm volatile( |
49 | " stpt %0\n" /* Store current cpu timer value */ | |
50 | " spt %1" /* Set new value imm. afterwards */ | |
51 | : "=m" (timer) : "m" (expires)); | |
9cfb9b3c MS |
52 | S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer; |
53 | S390_lowcore.last_update_timer = expires; | |
54 | } | |
55 | ||
27f6b416 MS |
56 | static 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 | ||
72d38b19 MS |
66 | static void update_mt_scaling(void) |
67 | { | |
68 | u64 cycles_new[8], *cycles_old; | |
69 | u64 delta, fac, mult, div; | |
70 | int i; | |
71 | ||
72 | stcctm5(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 | ||
b7394a5f MS |
94 | static 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 | ||
104 | static 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 | ||
b29e061b | 114 | static void account_system_index_scaled(struct task_struct *p, u64 cputime, |
b7394a5f MS |
115 | enum cpu_usage_stat index) |
116 | { | |
b29e061b | 117 | p->stimescaled += cputime_to_nsecs(scale_vtime(cputime)); |
fb8b049c | 118 | account_system_index_time(p, cputime_to_nsecs(cputime), index); |
b7394a5f MS |
119 | } |
120 | ||
1da177e4 LT |
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 | */ | |
8f2b468a | 125 | static int do_account_vtime(struct task_struct *tsk) |
1da177e4 | 126 | { |
b7394a5f | 127 | u64 timer, clock, user, guest, system, hardirq, softirq, steal; |
1da177e4 LT |
128 | |
129 | timer = S390_lowcore.last_update_timer; | |
130 | clock = S390_lowcore.last_update_clock; | |
27f6b416 MS |
131 | asm volatile( |
132 | " stpt %0\n" /* Store current cpu timer value */ | |
1f759bb3 MS |
133 | #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES |
134 | " stckf %1" /* Store current tod clock value */ | |
135 | #else | |
27f6b416 | 136 | " stck %1" /* Store current tod clock value */ |
1f759bb3 | 137 | #endif |
27f6b416 MS |
138 | : "=m" (S390_lowcore.last_update_timer), |
139 | "=m" (S390_lowcore.last_update_clock)); | |
b7394a5f MS |
140 | clock = S390_lowcore.last_update_clock - clock; |
141 | timer -= S390_lowcore.last_update_timer; | |
142 | ||
143 | if (hardirq_count()) | |
144 | S390_lowcore.hardirq_timer += timer; | |
145 | else | |
146 | S390_lowcore.system_timer += timer; | |
1da177e4 | 147 | |
72d38b19 | 148 | /* Update MT utilization calculation */ |
f341b8df | 149 | if (smp_cpu_mtid && |
72d38b19 MS |
150 | time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies))) |
151 | update_mt_scaling(); | |
10ad34bc | 152 | |
b7394a5f MS |
153 | /* Calculate cputime delta */ |
154 | user = update_tsk_timer(&tsk->thread.user_timer, | |
155 | READ_ONCE(S390_lowcore.user_timer)); | |
156 | guest = update_tsk_timer(&tsk->thread.guest_timer, | |
157 | READ_ONCE(S390_lowcore.guest_timer)); | |
158 | system = update_tsk_timer(&tsk->thread.system_timer, | |
159 | READ_ONCE(S390_lowcore.system_timer)); | |
160 | hardirq = update_tsk_timer(&tsk->thread.hardirq_timer, | |
161 | READ_ONCE(S390_lowcore.hardirq_timer)); | |
162 | softirq = update_tsk_timer(&tsk->thread.softirq_timer, | |
163 | READ_ONCE(S390_lowcore.softirq_timer)); | |
164 | S390_lowcore.steal_timer += | |
165 | clock - user - guest - system - hardirq - softirq; | |
166 | ||
167 | /* Push account value */ | |
168 | if (user) { | |
23244a5c | 169 | account_user_time(tsk, cputime_to_nsecs(user)); |
5613fda9 | 170 | tsk->utimescaled += cputime_to_nsecs(scale_vtime(user)); |
b7394a5f | 171 | } |
10ad34bc | 172 | |
b7394a5f | 173 | if (guest) { |
fb8b049c | 174 | account_guest_time(tsk, cputime_to_nsecs(guest)); |
5613fda9 | 175 | tsk->utimescaled += cputime_to_nsecs(scale_vtime(guest)); |
10ad34bc | 176 | } |
b7394a5f MS |
177 | |
178 | if (system) | |
b29e061b | 179 | account_system_index_scaled(tsk, system, CPUTIME_SYSTEM); |
b7394a5f | 180 | if (hardirq) |
b29e061b | 181 | account_system_index_scaled(tsk, hardirq, CPUTIME_IRQ); |
b7394a5f | 182 | if (softirq) |
b29e061b | 183 | account_system_index_scaled(tsk, softirq, CPUTIME_SOFTIRQ); |
1da177e4 | 184 | |
aa5e97ce MS |
185 | steal = S390_lowcore.steal_timer; |
186 | if ((s64) steal > 0) { | |
187 | S390_lowcore.steal_timer = 0; | |
be9095ed | 188 | account_steal_time(cputime_to_nsecs(steal)); |
1da177e4 | 189 | } |
27f6b416 | 190 | |
b7394a5f | 191 | return virt_timer_forward(user + guest + system + hardirq + softirq); |
1da177e4 LT |
192 | } |
193 | ||
bf9fae9f | 194 | void vtime_task_switch(struct task_struct *prev) |
1f1c12af | 195 | { |
8f2b468a | 196 | do_account_vtime(prev); |
90c53e65 | 197 | prev->thread.user_timer = S390_lowcore.user_timer; |
b7394a5f | 198 | prev->thread.guest_timer = S390_lowcore.guest_timer; |
90c53e65 | 199 | prev->thread.system_timer = S390_lowcore.system_timer; |
b7394a5f MS |
200 | prev->thread.hardirq_timer = S390_lowcore.hardirq_timer; |
201 | prev->thread.softirq_timer = S390_lowcore.softirq_timer; | |
90c53e65 | 202 | S390_lowcore.user_timer = current->thread.user_timer; |
b7394a5f | 203 | S390_lowcore.guest_timer = current->thread.guest_timer; |
90c53e65 | 204 | S390_lowcore.system_timer = current->thread.system_timer; |
b7394a5f MS |
205 | S390_lowcore.hardirq_timer = current->thread.hardirq_timer; |
206 | S390_lowcore.softirq_timer = current->thread.softirq_timer; | |
aa5e97ce | 207 | } |
1f1c12af | 208 | |
bcebdf84 FW |
209 | /* |
210 | * In s390, accounting pending user time also implies | |
211 | * accounting system time in order to correctly compute | |
212 | * the stolen time accounting. | |
213 | */ | |
c8d7dabf | 214 | void vtime_flush(struct task_struct *tsk) |
aa5e97ce | 215 | { |
8f2b468a | 216 | if (do_account_vtime(tsk)) |
27f6b416 | 217 | virt_timer_expire(); |
1f1c12af MS |
218 | } |
219 | ||
1da177e4 LT |
220 | /* |
221 | * Update process times based on virtual cpu times stored by entry.S | |
222 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
223 | */ | |
6a61671b | 224 | void vtime_account_irq_enter(struct task_struct *tsk) |
1da177e4 | 225 | { |
b7394a5f | 226 | u64 timer; |
1da177e4 LT |
227 | |
228 | timer = S390_lowcore.last_update_timer; | |
9cfb9b3c | 229 | S390_lowcore.last_update_timer = get_vtimer(); |
b7394a5f MS |
230 | timer -= S390_lowcore.last_update_timer; |
231 | ||
232 | if ((tsk->flags & PF_VCPU) && (irq_count() == 0)) | |
233 | S390_lowcore.guest_timer += timer; | |
234 | else if (hardirq_count()) | |
235 | S390_lowcore.hardirq_timer += timer; | |
236 | else if (in_serving_softirq()) | |
237 | S390_lowcore.softirq_timer += timer; | |
238 | else | |
239 | S390_lowcore.system_timer += timer; | |
240 | ||
241 | virt_timer_forward(timer); | |
1da177e4 | 242 | } |
6a61671b | 243 | EXPORT_SYMBOL_GPL(vtime_account_irq_enter); |
1da177e4 | 244 | |
fd25b4c2 | 245 | void vtime_account_system(struct task_struct *tsk) |
6a61671b | 246 | __attribute__((alias("vtime_account_irq_enter"))); |
fd25b4c2 | 247 | EXPORT_SYMBOL_GPL(vtime_account_system); |
11113334 | 248 | |
1da177e4 LT |
249 | /* |
250 | * Sorted add to a list. List is linear searched until first bigger | |
251 | * element is found. | |
252 | */ | |
253 | static void list_add_sorted(struct vtimer_list *timer, struct list_head *head) | |
254 | { | |
27f6b416 | 255 | struct vtimer_list *tmp; |
1da177e4 | 256 | |
27f6b416 MS |
257 | list_for_each_entry(tmp, head, entry) { |
258 | if (tmp->expires > timer->expires) { | |
259 | list_add_tail(&timer->entry, &tmp->entry); | |
1da177e4 LT |
260 | return; |
261 | } | |
262 | } | |
263 | list_add_tail(&timer->entry, head); | |
264 | } | |
265 | ||
266 | /* | |
27f6b416 | 267 | * Handler for expired virtual CPU timer. |
1da177e4 | 268 | */ |
27f6b416 | 269 | static void virt_timer_expire(void) |
1da177e4 | 270 | { |
27f6b416 MS |
271 | struct vtimer_list *timer, *tmp; |
272 | unsigned long elapsed; | |
273 | LIST_HEAD(cb_list); | |
274 | ||
275 | /* walk timer list, fire all expired timers */ | |
276 | spin_lock(&virt_timer_lock); | |
277 | elapsed = atomic64_read(&virt_timer_elapsed); | |
278 | list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) { | |
279 | if (timer->expires < elapsed) | |
9cfb9b3c | 280 | /* move expired timer to the callback queue */ |
27f6b416 | 281 | list_move_tail(&timer->entry, &cb_list); |
9cfb9b3c | 282 | else |
27f6b416 | 283 | timer->expires -= elapsed; |
1da177e4 | 284 | } |
27f6b416 MS |
285 | if (!list_empty(&virt_timer_list)) { |
286 | timer = list_first_entry(&virt_timer_list, | |
287 | struct vtimer_list, entry); | |
288 | atomic64_set(&virt_timer_current, timer->expires); | |
289 | } | |
290 | atomic64_sub(elapsed, &virt_timer_elapsed); | |
291 | spin_unlock(&virt_timer_lock); | |
292 | ||
293 | /* Do callbacks and recharge periodic timers */ | |
294 | list_for_each_entry_safe(timer, tmp, &cb_list, entry) { | |
295 | list_del_init(&timer->entry); | |
296 | timer->function(timer->data); | |
297 | if (timer->interval) { | |
298 | /* Recharge interval timer */ | |
299 | timer->expires = timer->interval + | |
300 | atomic64_read(&virt_timer_elapsed); | |
301 | spin_lock(&virt_timer_lock); | |
302 | list_add_sorted(timer, &virt_timer_list); | |
303 | spin_unlock(&virt_timer_lock); | |
304 | } | |
4c1051e3 | 305 | } |
1da177e4 LT |
306 | } |
307 | ||
308 | void init_virt_timer(struct vtimer_list *timer) | |
309 | { | |
1da177e4 LT |
310 | timer->function = NULL; |
311 | INIT_LIST_HEAD(&timer->entry); | |
1da177e4 LT |
312 | } |
313 | EXPORT_SYMBOL(init_virt_timer); | |
314 | ||
1da177e4 LT |
315 | static inline int vtimer_pending(struct vtimer_list *timer) |
316 | { | |
27f6b416 | 317 | return !list_empty(&timer->entry); |
1da177e4 LT |
318 | } |
319 | ||
1da177e4 LT |
320 | static void internal_add_vtimer(struct vtimer_list *timer) |
321 | { | |
27f6b416 MS |
322 | if (list_empty(&virt_timer_list)) { |
323 | /* First timer, just program it. */ | |
324 | atomic64_set(&virt_timer_current, timer->expires); | |
325 | atomic64_set(&virt_timer_elapsed, 0); | |
326 | list_add(&timer->entry, &virt_timer_list); | |
9cfb9b3c | 327 | } else { |
27f6b416 MS |
328 | /* Update timer against current base. */ |
329 | timer->expires += atomic64_read(&virt_timer_elapsed); | |
330 | if (likely((s64) timer->expires < | |
331 | (s64) atomic64_read(&virt_timer_current))) | |
9cfb9b3c | 332 | /* The new timer expires before the current timer. */ |
27f6b416 MS |
333 | atomic64_set(&virt_timer_current, timer->expires); |
334 | /* Insert new timer into the list. */ | |
335 | list_add_sorted(timer, &virt_timer_list); | |
1da177e4 | 336 | } |
1da177e4 LT |
337 | } |
338 | ||
27f6b416 | 339 | static void __add_vtimer(struct vtimer_list *timer, int periodic) |
1da177e4 | 340 | { |
27f6b416 MS |
341 | unsigned long flags; |
342 | ||
343 | timer->interval = periodic ? timer->expires : 0; | |
344 | spin_lock_irqsave(&virt_timer_lock, flags); | |
345 | internal_add_vtimer(timer); | |
346 | spin_unlock_irqrestore(&virt_timer_lock, flags); | |
1da177e4 LT |
347 | } |
348 | ||
349 | /* | |
0f5e1558 | 350 | * add_virt_timer - add a oneshot virtual CPU timer |
1da177e4 | 351 | */ |
27f6b416 | 352 | void add_virt_timer(struct vtimer_list *timer) |
1da177e4 | 353 | { |
27f6b416 | 354 | __add_vtimer(timer, 0); |
1da177e4 LT |
355 | } |
356 | EXPORT_SYMBOL(add_virt_timer); | |
357 | ||
358 | /* | |
359 | * add_virt_timer_int - add an interval virtual CPU timer | |
360 | */ | |
27f6b416 | 361 | void add_virt_timer_periodic(struct vtimer_list *timer) |
1da177e4 | 362 | { |
27f6b416 | 363 | __add_vtimer(timer, 1); |
1da177e4 LT |
364 | } |
365 | EXPORT_SYMBOL(add_virt_timer_periodic); | |
366 | ||
27f6b416 | 367 | static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic) |
1da177e4 | 368 | { |
1da177e4 | 369 | unsigned long flags; |
27f6b416 | 370 | int rc; |
1da177e4 | 371 | |
ca366a32 | 372 | BUG_ON(!timer->function); |
1da177e4 | 373 | |
1da177e4 LT |
374 | if (timer->expires == expires && vtimer_pending(timer)) |
375 | return 1; | |
27f6b416 MS |
376 | spin_lock_irqsave(&virt_timer_lock, flags); |
377 | rc = vtimer_pending(timer); | |
378 | if (rc) | |
379 | list_del_init(&timer->entry); | |
380 | timer->interval = periodic ? expires : 0; | |
1da177e4 | 381 | timer->expires = expires; |
1da177e4 | 382 | internal_add_vtimer(timer); |
27f6b416 MS |
383 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
384 | return rc; | |
1da177e4 | 385 | } |
b6ecfa92 JG |
386 | |
387 | /* | |
b6ecfa92 JG |
388 | * returns whether it has modified a pending timer (1) or not (0) |
389 | */ | |
27f6b416 | 390 | int mod_virt_timer(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
391 | { |
392 | return __mod_vtimer(timer, expires, 0); | |
393 | } | |
1da177e4 LT |
394 | EXPORT_SYMBOL(mod_virt_timer); |
395 | ||
b6ecfa92 | 396 | /* |
b6ecfa92 JG |
397 | * returns whether it has modified a pending timer (1) or not (0) |
398 | */ | |
27f6b416 | 399 | int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
400 | { |
401 | return __mod_vtimer(timer, expires, 1); | |
402 | } | |
403 | EXPORT_SYMBOL(mod_virt_timer_periodic); | |
404 | ||
1da177e4 | 405 | /* |
27f6b416 | 406 | * Delete a virtual timer. |
1da177e4 LT |
407 | * |
408 | * returns whether the deleted timer was pending (1) or not (0) | |
409 | */ | |
410 | int del_virt_timer(struct vtimer_list *timer) | |
411 | { | |
412 | unsigned long flags; | |
1da177e4 | 413 | |
1da177e4 LT |
414 | if (!vtimer_pending(timer)) |
415 | return 0; | |
27f6b416 | 416 | spin_lock_irqsave(&virt_timer_lock, flags); |
1da177e4 | 417 | list_del_init(&timer->entry); |
27f6b416 | 418 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
1da177e4 LT |
419 | return 1; |
420 | } | |
421 | EXPORT_SYMBOL(del_virt_timer); | |
422 | ||
423 | /* | |
424 | * Start the virtual CPU timer on the current CPU. | |
425 | */ | |
b5f87f15 | 426 | void vtime_init(void) |
1da177e4 | 427 | { |
8b646bd7 | 428 | /* set initial cpu timer */ |
27f6b416 | 429 | set_vtimer(VTIMER_MAX_SLICE); |
f341b8df MS |
430 | /* Setup initial MT scaling values */ |
431 | if (smp_cpu_mtid) { | |
432 | __this_cpu_write(mt_scaling_jiffies, jiffies); | |
433 | __this_cpu_write(mt_scaling_mult, 1); | |
434 | __this_cpu_write(mt_scaling_div, 1); | |
435 | stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles)); | |
436 | } | |
1da177e4 | 437 | } |