Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Implement CPU time clocks for the POSIX clock interface. | |
3 | */ | |
4 | ||
5 | #include <linux/sched.h> | |
6 | #include <linux/posix-timers.h> | |
1da177e4 | 7 | #include <linux/errno.h> |
f8bd2258 RZ |
8 | #include <linux/math64.h> |
9 | #include <asm/uaccess.h> | |
bb34d92f | 10 | #include <linux/kernel_stat.h> |
3f0a525e | 11 | #include <trace/events/timer.h> |
61337054 | 12 | #include <linux/random.h> |
a8572160 FW |
13 | #include <linux/tick.h> |
14 | #include <linux/workqueue.h> | |
1da177e4 | 15 | |
f06febc9 | 16 | /* |
f55db609 SG |
17 | * Called after updating RLIMIT_CPU to run cpu timer and update |
18 | * tsk->signal->cputime_expires expiration cache if necessary. Needs | |
19 | * siglock protection since other code may update expiration cache as | |
20 | * well. | |
f06febc9 | 21 | */ |
5ab46b34 | 22 | void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new) |
f06febc9 | 23 | { |
42c4ab41 | 24 | cputime_t cputime = secs_to_cputime(rlim_new); |
f06febc9 | 25 | |
5ab46b34 JS |
26 | spin_lock_irq(&task->sighand->siglock); |
27 | set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL); | |
28 | spin_unlock_irq(&task->sighand->siglock); | |
f06febc9 FM |
29 | } |
30 | ||
a924b04d | 31 | static int check_clock(const clockid_t which_clock) |
1da177e4 LT |
32 | { |
33 | int error = 0; | |
34 | struct task_struct *p; | |
35 | const pid_t pid = CPUCLOCK_PID(which_clock); | |
36 | ||
37 | if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX) | |
38 | return -EINVAL; | |
39 | ||
40 | if (pid == 0) | |
41 | return 0; | |
42 | ||
c0deae8c | 43 | rcu_read_lock(); |
8dc86af0 | 44 | p = find_task_by_vpid(pid); |
bac0abd6 | 45 | if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ? |
c0deae8c | 46 | same_thread_group(p, current) : has_group_leader_pid(p))) { |
1da177e4 LT |
47 | error = -EINVAL; |
48 | } | |
c0deae8c | 49 | rcu_read_unlock(); |
1da177e4 LT |
50 | |
51 | return error; | |
52 | } | |
53 | ||
55ccb616 | 54 | static inline unsigned long long |
a924b04d | 55 | timespec_to_sample(const clockid_t which_clock, const struct timespec *tp) |
1da177e4 | 56 | { |
55ccb616 FW |
57 | unsigned long long ret; |
58 | ||
59 | ret = 0; /* high half always zero when .cpu used */ | |
1da177e4 | 60 | if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) { |
55ccb616 | 61 | ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec; |
1da177e4 | 62 | } else { |
55ccb616 | 63 | ret = cputime_to_expires(timespec_to_cputime(tp)); |
1da177e4 LT |
64 | } |
65 | return ret; | |
66 | } | |
67 | ||
a924b04d | 68 | static void sample_to_timespec(const clockid_t which_clock, |
55ccb616 | 69 | unsigned long long expires, |
1da177e4 LT |
70 | struct timespec *tp) |
71 | { | |
f8bd2258 | 72 | if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) |
55ccb616 | 73 | *tp = ns_to_timespec(expires); |
f8bd2258 | 74 | else |
55ccb616 | 75 | cputime_to_timespec((__force cputime_t)expires, tp); |
1da177e4 LT |
76 | } |
77 | ||
78 | /* | |
79 | * Update expiry time from increment, and increase overrun count, | |
80 | * given the current clock sample. | |
81 | */ | |
7a4ed937 | 82 | static void bump_cpu_timer(struct k_itimer *timer, |
55ccb616 | 83 | unsigned long long now) |
1da177e4 LT |
84 | { |
85 | int i; | |
55ccb616 | 86 | unsigned long long delta, incr; |
1da177e4 | 87 | |
55ccb616 | 88 | if (timer->it.cpu.incr == 0) |
1da177e4 LT |
89 | return; |
90 | ||
55ccb616 FW |
91 | if (now < timer->it.cpu.expires) |
92 | return; | |
1da177e4 | 93 | |
55ccb616 FW |
94 | incr = timer->it.cpu.incr; |
95 | delta = now + incr - timer->it.cpu.expires; | |
1da177e4 | 96 | |
55ccb616 FW |
97 | /* Don't use (incr*2 < delta), incr*2 might overflow. */ |
98 | for (i = 0; incr < delta - incr; i++) | |
99 | incr = incr << 1; | |
100 | ||
101 | for (; i >= 0; incr >>= 1, i--) { | |
102 | if (delta < incr) | |
103 | continue; | |
104 | ||
105 | timer->it.cpu.expires += incr; | |
106 | timer->it_overrun += 1 << i; | |
107 | delta -= incr; | |
1da177e4 LT |
108 | } |
109 | } | |
110 | ||
555347f6 FW |
111 | /** |
112 | * task_cputime_zero - Check a task_cputime struct for all zero fields. | |
113 | * | |
114 | * @cputime: The struct to compare. | |
115 | * | |
116 | * Checks @cputime to see if all fields are zero. Returns true if all fields | |
117 | * are zero, false if any field is nonzero. | |
118 | */ | |
119 | static inline int task_cputime_zero(const struct task_cputime *cputime) | |
120 | { | |
121 | if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime) | |
122 | return 1; | |
123 | return 0; | |
124 | } | |
125 | ||
55ccb616 | 126 | static inline unsigned long long prof_ticks(struct task_struct *p) |
1da177e4 | 127 | { |
6fac4829 FW |
128 | cputime_t utime, stime; |
129 | ||
130 | task_cputime(p, &utime, &stime); | |
131 | ||
55ccb616 | 132 | return cputime_to_expires(utime + stime); |
1da177e4 | 133 | } |
55ccb616 | 134 | static inline unsigned long long virt_ticks(struct task_struct *p) |
1da177e4 | 135 | { |
6fac4829 FW |
136 | cputime_t utime; |
137 | ||
138 | task_cputime(p, &utime, NULL); | |
139 | ||
55ccb616 | 140 | return cputime_to_expires(utime); |
1da177e4 | 141 | } |
1da177e4 | 142 | |
bc2c8ea4 TG |
143 | static int |
144 | posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp) | |
1da177e4 LT |
145 | { |
146 | int error = check_clock(which_clock); | |
147 | if (!error) { | |
148 | tp->tv_sec = 0; | |
149 | tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ); | |
150 | if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) { | |
151 | /* | |
152 | * If sched_clock is using a cycle counter, we | |
153 | * don't have any idea of its true resolution | |
154 | * exported, but it is much more than 1s/HZ. | |
155 | */ | |
156 | tp->tv_nsec = 1; | |
157 | } | |
158 | } | |
159 | return error; | |
160 | } | |
161 | ||
bc2c8ea4 TG |
162 | static int |
163 | posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp) | |
1da177e4 LT |
164 | { |
165 | /* | |
166 | * You can never reset a CPU clock, but we check for other errors | |
167 | * in the call before failing with EPERM. | |
168 | */ | |
169 | int error = check_clock(which_clock); | |
170 | if (error == 0) { | |
171 | error = -EPERM; | |
172 | } | |
173 | return error; | |
174 | } | |
175 | ||
176 | ||
177 | /* | |
178 | * Sample a per-thread clock for the given task. | |
179 | */ | |
a924b04d | 180 | static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p, |
55ccb616 | 181 | unsigned long long *sample) |
1da177e4 LT |
182 | { |
183 | switch (CPUCLOCK_WHICH(which_clock)) { | |
184 | default: | |
185 | return -EINVAL; | |
186 | case CPUCLOCK_PROF: | |
55ccb616 | 187 | *sample = prof_ticks(p); |
1da177e4 LT |
188 | break; |
189 | case CPUCLOCK_VIRT: | |
55ccb616 | 190 | *sample = virt_ticks(p); |
1da177e4 LT |
191 | break; |
192 | case CPUCLOCK_SCHED: | |
55ccb616 | 193 | *sample = task_sched_runtime(p); |
1da177e4 LT |
194 | break; |
195 | } | |
196 | return 0; | |
197 | } | |
198 | ||
4da94d49 PZ |
199 | static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b) |
200 | { | |
64861634 | 201 | if (b->utime > a->utime) |
4da94d49 PZ |
202 | a->utime = b->utime; |
203 | ||
64861634 | 204 | if (b->stime > a->stime) |
4da94d49 PZ |
205 | a->stime = b->stime; |
206 | ||
207 | if (b->sum_exec_runtime > a->sum_exec_runtime) | |
208 | a->sum_exec_runtime = b->sum_exec_runtime; | |
209 | } | |
210 | ||
211 | void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times) | |
212 | { | |
213 | struct thread_group_cputimer *cputimer = &tsk->signal->cputimer; | |
214 | struct task_cputime sum; | |
215 | unsigned long flags; | |
216 | ||
4da94d49 | 217 | if (!cputimer->running) { |
4da94d49 PZ |
218 | /* |
219 | * The POSIX timer interface allows for absolute time expiry | |
220 | * values through the TIMER_ABSTIME flag, therefore we have | |
221 | * to synchronize the timer to the clock every time we start | |
222 | * it. | |
223 | */ | |
224 | thread_group_cputime(tsk, &sum); | |
3cfef952 | 225 | raw_spin_lock_irqsave(&cputimer->lock, flags); |
bcd5cff7 | 226 | cputimer->running = 1; |
4da94d49 | 227 | update_gt_cputime(&cputimer->cputime, &sum); |
bcd5cff7 | 228 | } else |
3cfef952 | 229 | raw_spin_lock_irqsave(&cputimer->lock, flags); |
4da94d49 | 230 | *times = cputimer->cputime; |
ee30a7b2 | 231 | raw_spin_unlock_irqrestore(&cputimer->lock, flags); |
4da94d49 PZ |
232 | } |
233 | ||
1da177e4 LT |
234 | /* |
235 | * Sample a process (thread group) clock for the given group_leader task. | |
e73d84e3 FW |
236 | * Must be called with task sighand lock held for safe while_each_thread() |
237 | * traversal. | |
1da177e4 | 238 | */ |
bb34d92f FM |
239 | static int cpu_clock_sample_group(const clockid_t which_clock, |
240 | struct task_struct *p, | |
55ccb616 | 241 | unsigned long long *sample) |
1da177e4 | 242 | { |
f06febc9 FM |
243 | struct task_cputime cputime; |
244 | ||
eccdaeaf | 245 | switch (CPUCLOCK_WHICH(which_clock)) { |
1da177e4 LT |
246 | default: |
247 | return -EINVAL; | |
248 | case CPUCLOCK_PROF: | |
c5f8d995 | 249 | thread_group_cputime(p, &cputime); |
55ccb616 | 250 | *sample = cputime_to_expires(cputime.utime + cputime.stime); |
1da177e4 LT |
251 | break; |
252 | case CPUCLOCK_VIRT: | |
c5f8d995 | 253 | thread_group_cputime(p, &cputime); |
55ccb616 | 254 | *sample = cputime_to_expires(cputime.utime); |
1da177e4 LT |
255 | break; |
256 | case CPUCLOCK_SCHED: | |
d670ec13 | 257 | thread_group_cputime(p, &cputime); |
55ccb616 | 258 | *sample = cputime.sum_exec_runtime; |
1da177e4 LT |
259 | break; |
260 | } | |
261 | return 0; | |
262 | } | |
263 | ||
33ab0fec FW |
264 | static int posix_cpu_clock_get_task(struct task_struct *tsk, |
265 | const clockid_t which_clock, | |
266 | struct timespec *tp) | |
267 | { | |
268 | int err = -EINVAL; | |
269 | unsigned long long rtn; | |
270 | ||
271 | if (CPUCLOCK_PERTHREAD(which_clock)) { | |
272 | if (same_thread_group(tsk, current)) | |
273 | err = cpu_clock_sample(which_clock, tsk, &rtn); | |
274 | } else { | |
50875788 FW |
275 | unsigned long flags; |
276 | struct sighand_struct *sighand; | |
33ab0fec | 277 | |
50875788 FW |
278 | /* |
279 | * while_each_thread() is not yet entirely RCU safe, | |
280 | * keep locking the group while sampling process | |
281 | * clock for now. | |
282 | */ | |
283 | sighand = lock_task_sighand(tsk, &flags); | |
284 | if (!sighand) | |
285 | return err; | |
286 | ||
287 | if (tsk == current || thread_group_leader(tsk)) | |
33ab0fec FW |
288 | err = cpu_clock_sample_group(which_clock, tsk, &rtn); |
289 | ||
50875788 | 290 | unlock_task_sighand(tsk, &flags); |
33ab0fec FW |
291 | } |
292 | ||
293 | if (!err) | |
294 | sample_to_timespec(which_clock, rtn, tp); | |
295 | ||
296 | return err; | |
297 | } | |
298 | ||
1da177e4 | 299 | |
bc2c8ea4 | 300 | static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp) |
1da177e4 LT |
301 | { |
302 | const pid_t pid = CPUCLOCK_PID(which_clock); | |
33ab0fec | 303 | int err = -EINVAL; |
1da177e4 LT |
304 | |
305 | if (pid == 0) { | |
306 | /* | |
307 | * Special case constant value for our own clocks. | |
308 | * We don't have to do any lookup to find ourselves. | |
309 | */ | |
33ab0fec | 310 | err = posix_cpu_clock_get_task(current, which_clock, tp); |
1da177e4 LT |
311 | } else { |
312 | /* | |
313 | * Find the given PID, and validate that the caller | |
314 | * should be able to see it. | |
315 | */ | |
316 | struct task_struct *p; | |
1f2ea083 | 317 | rcu_read_lock(); |
8dc86af0 | 318 | p = find_task_by_vpid(pid); |
33ab0fec FW |
319 | if (p) |
320 | err = posix_cpu_clock_get_task(p, which_clock, tp); | |
1f2ea083 | 321 | rcu_read_unlock(); |
1da177e4 LT |
322 | } |
323 | ||
33ab0fec | 324 | return err; |
1da177e4 LT |
325 | } |
326 | ||
327 | ||
328 | /* | |
329 | * Validate the clockid_t for a new CPU-clock timer, and initialize the timer. | |
ba5ea951 SG |
330 | * This is called from sys_timer_create() and do_cpu_nanosleep() with the |
331 | * new timer already all-zeros initialized. | |
1da177e4 | 332 | */ |
bc2c8ea4 | 333 | static int posix_cpu_timer_create(struct k_itimer *new_timer) |
1da177e4 LT |
334 | { |
335 | int ret = 0; | |
336 | const pid_t pid = CPUCLOCK_PID(new_timer->it_clock); | |
337 | struct task_struct *p; | |
338 | ||
339 | if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX) | |
340 | return -EINVAL; | |
341 | ||
342 | INIT_LIST_HEAD(&new_timer->it.cpu.entry); | |
1da177e4 | 343 | |
c0deae8c | 344 | rcu_read_lock(); |
1da177e4 LT |
345 | if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) { |
346 | if (pid == 0) { | |
347 | p = current; | |
348 | } else { | |
8dc86af0 | 349 | p = find_task_by_vpid(pid); |
bac0abd6 | 350 | if (p && !same_thread_group(p, current)) |
1da177e4 LT |
351 | p = NULL; |
352 | } | |
353 | } else { | |
354 | if (pid == 0) { | |
355 | p = current->group_leader; | |
356 | } else { | |
8dc86af0 | 357 | p = find_task_by_vpid(pid); |
c0deae8c | 358 | if (p && !has_group_leader_pid(p)) |
1da177e4 LT |
359 | p = NULL; |
360 | } | |
361 | } | |
362 | new_timer->it.cpu.task = p; | |
363 | if (p) { | |
364 | get_task_struct(p); | |
365 | } else { | |
366 | ret = -EINVAL; | |
367 | } | |
c0deae8c | 368 | rcu_read_unlock(); |
1da177e4 LT |
369 | |
370 | return ret; | |
371 | } | |
372 | ||
373 | /* | |
374 | * Clean up a CPU-clock timer that is about to be destroyed. | |
375 | * This is called from timer deletion with the timer already locked. | |
376 | * If we return TIMER_RETRY, it's necessary to release the timer's lock | |
377 | * and try again. (This happens when the timer is in the middle of firing.) | |
378 | */ | |
bc2c8ea4 | 379 | static int posix_cpu_timer_del(struct k_itimer *timer) |
1da177e4 | 380 | { |
108150ea | 381 | int ret = 0; |
3d7a1427 FW |
382 | unsigned long flags; |
383 | struct sighand_struct *sighand; | |
384 | struct task_struct *p = timer->it.cpu.task; | |
1da177e4 | 385 | |
a3222f88 | 386 | WARN_ON_ONCE(p == NULL); |
108150ea | 387 | |
3d7a1427 FW |
388 | /* |
389 | * Protect against sighand release/switch in exit/exec and process/ | |
390 | * thread timer list entry concurrent read/writes. | |
391 | */ | |
392 | sighand = lock_task_sighand(p, &flags); | |
393 | if (unlikely(sighand == NULL)) { | |
a3222f88 FW |
394 | /* |
395 | * We raced with the reaping of the task. | |
396 | * The deletion should have cleared us off the list. | |
397 | */ | |
531f64fd | 398 | WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry)); |
a3222f88 | 399 | } else { |
a3222f88 FW |
400 | if (timer->it.cpu.firing) |
401 | ret = TIMER_RETRY; | |
402 | else | |
403 | list_del(&timer->it.cpu.entry); | |
3d7a1427 FW |
404 | |
405 | unlock_task_sighand(p, &flags); | |
1da177e4 | 406 | } |
a3222f88 FW |
407 | |
408 | if (!ret) | |
409 | put_task_struct(p); | |
1da177e4 | 410 | |
108150ea | 411 | return ret; |
1da177e4 LT |
412 | } |
413 | ||
af82eb3c | 414 | static void cleanup_timers_list(struct list_head *head) |
1a7fa510 FW |
415 | { |
416 | struct cpu_timer_list *timer, *next; | |
417 | ||
a0b2062b | 418 | list_for_each_entry_safe(timer, next, head, entry) |
1a7fa510 | 419 | list_del_init(&timer->entry); |
1a7fa510 FW |
420 | } |
421 | ||
1da177e4 LT |
422 | /* |
423 | * Clean out CPU timers still ticking when a thread exited. The task | |
424 | * pointer is cleared, and the expiry time is replaced with the residual | |
425 | * time for later timer_gettime calls to return. | |
426 | * This must be called with the siglock held. | |
427 | */ | |
af82eb3c | 428 | static void cleanup_timers(struct list_head *head) |
1da177e4 | 429 | { |
af82eb3c FW |
430 | cleanup_timers_list(head); |
431 | cleanup_timers_list(++head); | |
432 | cleanup_timers_list(++head); | |
1da177e4 LT |
433 | } |
434 | ||
435 | /* | |
436 | * These are both called with the siglock held, when the current thread | |
437 | * is being reaped. When the final (leader) thread in the group is reaped, | |
438 | * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit. | |
439 | */ | |
440 | void posix_cpu_timers_exit(struct task_struct *tsk) | |
441 | { | |
61337054 NK |
442 | add_device_randomness((const void*) &tsk->se.sum_exec_runtime, |
443 | sizeof(unsigned long long)); | |
af82eb3c | 444 | cleanup_timers(tsk->cpu_timers); |
1da177e4 LT |
445 | |
446 | } | |
447 | void posix_cpu_timers_exit_group(struct task_struct *tsk) | |
448 | { | |
af82eb3c | 449 | cleanup_timers(tsk->signal->cpu_timers); |
1da177e4 LT |
450 | } |
451 | ||
d1e3b6d1 SG |
452 | static inline int expires_gt(cputime_t expires, cputime_t new_exp) |
453 | { | |
64861634 | 454 | return expires == 0 || expires > new_exp; |
d1e3b6d1 SG |
455 | } |
456 | ||
1da177e4 LT |
457 | /* |
458 | * Insert the timer on the appropriate list before any timers that | |
e73d84e3 | 459 | * expire later. This must be called with the sighand lock held. |
1da177e4 | 460 | */ |
5eb9aa64 | 461 | static void arm_timer(struct k_itimer *timer) |
1da177e4 LT |
462 | { |
463 | struct task_struct *p = timer->it.cpu.task; | |
464 | struct list_head *head, *listpos; | |
5eb9aa64 | 465 | struct task_cputime *cputime_expires; |
1da177e4 LT |
466 | struct cpu_timer_list *const nt = &timer->it.cpu; |
467 | struct cpu_timer_list *next; | |
1da177e4 | 468 | |
5eb9aa64 SG |
469 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { |
470 | head = p->cpu_timers; | |
471 | cputime_expires = &p->cputime_expires; | |
472 | } else { | |
473 | head = p->signal->cpu_timers; | |
474 | cputime_expires = &p->signal->cputime_expires; | |
475 | } | |
1da177e4 LT |
476 | head += CPUCLOCK_WHICH(timer->it_clock); |
477 | ||
1da177e4 | 478 | listpos = head; |
5eb9aa64 | 479 | list_for_each_entry(next, head, entry) { |
55ccb616 | 480 | if (nt->expires < next->expires) |
5eb9aa64 SG |
481 | break; |
482 | listpos = &next->entry; | |
1da177e4 LT |
483 | } |
484 | list_add(&nt->entry, listpos); | |
485 | ||
486 | if (listpos == head) { | |
55ccb616 | 487 | unsigned long long exp = nt->expires; |
5eb9aa64 | 488 | |
1da177e4 | 489 | /* |
5eb9aa64 SG |
490 | * We are the new earliest-expiring POSIX 1.b timer, hence |
491 | * need to update expiration cache. Take into account that | |
492 | * for process timers we share expiration cache with itimers | |
493 | * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME. | |
1da177e4 LT |
494 | */ |
495 | ||
5eb9aa64 SG |
496 | switch (CPUCLOCK_WHICH(timer->it_clock)) { |
497 | case CPUCLOCK_PROF: | |
55ccb616 FW |
498 | if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp))) |
499 | cputime_expires->prof_exp = expires_to_cputime(exp); | |
5eb9aa64 SG |
500 | break; |
501 | case CPUCLOCK_VIRT: | |
55ccb616 FW |
502 | if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp))) |
503 | cputime_expires->virt_exp = expires_to_cputime(exp); | |
5eb9aa64 SG |
504 | break; |
505 | case CPUCLOCK_SCHED: | |
506 | if (cputime_expires->sched_exp == 0 || | |
55ccb616 FW |
507 | cputime_expires->sched_exp > exp) |
508 | cputime_expires->sched_exp = exp; | |
5eb9aa64 | 509 | break; |
1da177e4 LT |
510 | } |
511 | } | |
1da177e4 LT |
512 | } |
513 | ||
514 | /* | |
515 | * The timer is locked, fire it and arrange for its reload. | |
516 | */ | |
517 | static void cpu_timer_fire(struct k_itimer *timer) | |
518 | { | |
1f169f84 SG |
519 | if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { |
520 | /* | |
521 | * User don't want any signal. | |
522 | */ | |
55ccb616 | 523 | timer->it.cpu.expires = 0; |
1f169f84 | 524 | } else if (unlikely(timer->sigq == NULL)) { |
1da177e4 LT |
525 | /* |
526 | * This a special case for clock_nanosleep, | |
527 | * not a normal timer from sys_timer_create. | |
528 | */ | |
529 | wake_up_process(timer->it_process); | |
55ccb616 FW |
530 | timer->it.cpu.expires = 0; |
531 | } else if (timer->it.cpu.incr == 0) { | |
1da177e4 LT |
532 | /* |
533 | * One-shot timer. Clear it as soon as it's fired. | |
534 | */ | |
535 | posix_timer_event(timer, 0); | |
55ccb616 | 536 | timer->it.cpu.expires = 0; |
1da177e4 LT |
537 | } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) { |
538 | /* | |
539 | * The signal did not get queued because the signal | |
540 | * was ignored, so we won't get any callback to | |
541 | * reload the timer. But we need to keep it | |
542 | * ticking in case the signal is deliverable next time. | |
543 | */ | |
544 | posix_cpu_timer_schedule(timer); | |
545 | } | |
546 | } | |
547 | ||
3997ad31 PZ |
548 | /* |
549 | * Sample a process (thread group) timer for the given group_leader task. | |
e73d84e3 FW |
550 | * Must be called with task sighand lock held for safe while_each_thread() |
551 | * traversal. | |
3997ad31 PZ |
552 | */ |
553 | static int cpu_timer_sample_group(const clockid_t which_clock, | |
554 | struct task_struct *p, | |
55ccb616 | 555 | unsigned long long *sample) |
3997ad31 PZ |
556 | { |
557 | struct task_cputime cputime; | |
558 | ||
559 | thread_group_cputimer(p, &cputime); | |
560 | switch (CPUCLOCK_WHICH(which_clock)) { | |
561 | default: | |
562 | return -EINVAL; | |
563 | case CPUCLOCK_PROF: | |
55ccb616 | 564 | *sample = cputime_to_expires(cputime.utime + cputime.stime); |
3997ad31 PZ |
565 | break; |
566 | case CPUCLOCK_VIRT: | |
55ccb616 | 567 | *sample = cputime_to_expires(cputime.utime); |
3997ad31 PZ |
568 | break; |
569 | case CPUCLOCK_SCHED: | |
55ccb616 | 570 | *sample = cputime.sum_exec_runtime + task_delta_exec(p); |
3997ad31 PZ |
571 | break; |
572 | } | |
573 | return 0; | |
574 | } | |
575 | ||
a8572160 FW |
576 | #ifdef CONFIG_NO_HZ_FULL |
577 | static void nohz_kick_work_fn(struct work_struct *work) | |
578 | { | |
579 | tick_nohz_full_kick_all(); | |
580 | } | |
581 | ||
582 | static DECLARE_WORK(nohz_kick_work, nohz_kick_work_fn); | |
583 | ||
584 | /* | |
585 | * We need the IPIs to be sent from sane process context. | |
586 | * The posix cpu timers are always set with irqs disabled. | |
587 | */ | |
588 | static void posix_cpu_timer_kick_nohz(void) | |
589 | { | |
d4283c65 FW |
590 | if (context_tracking_is_enabled()) |
591 | schedule_work(&nohz_kick_work); | |
a8572160 | 592 | } |
555347f6 FW |
593 | |
594 | bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk) | |
595 | { | |
596 | if (!task_cputime_zero(&tsk->cputime_expires)) | |
6ac29178 | 597 | return false; |
555347f6 FW |
598 | |
599 | if (tsk->signal->cputimer.running) | |
6ac29178 | 600 | return false; |
555347f6 | 601 | |
6ac29178 | 602 | return true; |
555347f6 | 603 | } |
a8572160 FW |
604 | #else |
605 | static inline void posix_cpu_timer_kick_nohz(void) { } | |
606 | #endif | |
607 | ||
1da177e4 LT |
608 | /* |
609 | * Guts of sys_timer_settime for CPU timers. | |
610 | * This is called with the timer locked and interrupts disabled. | |
611 | * If we return TIMER_RETRY, it's necessary to release the timer's lock | |
612 | * and try again. (This happens when the timer is in the middle of firing.) | |
613 | */ | |
e73d84e3 | 614 | static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags, |
bc2c8ea4 | 615 | struct itimerspec *new, struct itimerspec *old) |
1da177e4 | 616 | { |
e73d84e3 FW |
617 | unsigned long flags; |
618 | struct sighand_struct *sighand; | |
1da177e4 | 619 | struct task_struct *p = timer->it.cpu.task; |
55ccb616 | 620 | unsigned long long old_expires, new_expires, old_incr, val; |
1da177e4 LT |
621 | int ret; |
622 | ||
a3222f88 | 623 | WARN_ON_ONCE(p == NULL); |
1da177e4 LT |
624 | |
625 | new_expires = timespec_to_sample(timer->it_clock, &new->it_value); | |
626 | ||
1da177e4 | 627 | /* |
e73d84e3 FW |
628 | * Protect against sighand release/switch in exit/exec and p->cpu_timers |
629 | * and p->signal->cpu_timers read/write in arm_timer() | |
630 | */ | |
631 | sighand = lock_task_sighand(p, &flags); | |
632 | /* | |
633 | * If p has just been reaped, we can no | |
1da177e4 LT |
634 | * longer get any information about it at all. |
635 | */ | |
e73d84e3 | 636 | if (unlikely(sighand == NULL)) { |
1da177e4 LT |
637 | return -ESRCH; |
638 | } | |
639 | ||
640 | /* | |
641 | * Disarm any old timer after extracting its expiry time. | |
642 | */ | |
531f64fd | 643 | WARN_ON_ONCE(!irqs_disabled()); |
a69ac4a7 ON |
644 | |
645 | ret = 0; | |
ae1a78ee | 646 | old_incr = timer->it.cpu.incr; |
1da177e4 | 647 | old_expires = timer->it.cpu.expires; |
a69ac4a7 ON |
648 | if (unlikely(timer->it.cpu.firing)) { |
649 | timer->it.cpu.firing = -1; | |
650 | ret = TIMER_RETRY; | |
651 | } else | |
652 | list_del_init(&timer->it.cpu.entry); | |
1da177e4 LT |
653 | |
654 | /* | |
655 | * We need to sample the current value to convert the new | |
656 | * value from to relative and absolute, and to convert the | |
657 | * old value from absolute to relative. To set a process | |
658 | * timer, we need a sample to balance the thread expiry | |
659 | * times (in arm_timer). With an absolute time, we must | |
660 | * check if it's already passed. In short, we need a sample. | |
661 | */ | |
662 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
663 | cpu_clock_sample(timer->it_clock, p, &val); | |
664 | } else { | |
3997ad31 | 665 | cpu_timer_sample_group(timer->it_clock, p, &val); |
1da177e4 LT |
666 | } |
667 | ||
668 | if (old) { | |
55ccb616 | 669 | if (old_expires == 0) { |
1da177e4 LT |
670 | old->it_value.tv_sec = 0; |
671 | old->it_value.tv_nsec = 0; | |
672 | } else { | |
673 | /* | |
674 | * Update the timer in case it has | |
675 | * overrun already. If it has, | |
676 | * we'll report it as having overrun | |
677 | * and with the next reloaded timer | |
678 | * already ticking, though we are | |
679 | * swallowing that pending | |
680 | * notification here to install the | |
681 | * new setting. | |
682 | */ | |
683 | bump_cpu_timer(timer, val); | |
55ccb616 FW |
684 | if (val < timer->it.cpu.expires) { |
685 | old_expires = timer->it.cpu.expires - val; | |
1da177e4 LT |
686 | sample_to_timespec(timer->it_clock, |
687 | old_expires, | |
688 | &old->it_value); | |
689 | } else { | |
690 | old->it_value.tv_nsec = 1; | |
691 | old->it_value.tv_sec = 0; | |
692 | } | |
693 | } | |
694 | } | |
695 | ||
a69ac4a7 | 696 | if (unlikely(ret)) { |
1da177e4 LT |
697 | /* |
698 | * We are colliding with the timer actually firing. | |
699 | * Punt after filling in the timer's old value, and | |
700 | * disable this firing since we are already reporting | |
701 | * it as an overrun (thanks to bump_cpu_timer above). | |
702 | */ | |
e73d84e3 | 703 | unlock_task_sighand(p, &flags); |
1da177e4 LT |
704 | goto out; |
705 | } | |
706 | ||
e73d84e3 | 707 | if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) { |
55ccb616 | 708 | new_expires += val; |
1da177e4 LT |
709 | } |
710 | ||
711 | /* | |
712 | * Install the new expiry time (or zero). | |
713 | * For a timer with no notification action, we don't actually | |
714 | * arm the timer (we'll just fake it for timer_gettime). | |
715 | */ | |
716 | timer->it.cpu.expires = new_expires; | |
55ccb616 | 717 | if (new_expires != 0 && val < new_expires) { |
5eb9aa64 | 718 | arm_timer(timer); |
1da177e4 LT |
719 | } |
720 | ||
e73d84e3 | 721 | unlock_task_sighand(p, &flags); |
1da177e4 LT |
722 | /* |
723 | * Install the new reload setting, and | |
724 | * set up the signal and overrun bookkeeping. | |
725 | */ | |
726 | timer->it.cpu.incr = timespec_to_sample(timer->it_clock, | |
727 | &new->it_interval); | |
728 | ||
729 | /* | |
730 | * This acts as a modification timestamp for the timer, | |
731 | * so any automatic reload attempt will punt on seeing | |
732 | * that we have reset the timer manually. | |
733 | */ | |
734 | timer->it_requeue_pending = (timer->it_requeue_pending + 2) & | |
735 | ~REQUEUE_PENDING; | |
736 | timer->it_overrun_last = 0; | |
737 | timer->it_overrun = -1; | |
738 | ||
55ccb616 | 739 | if (new_expires != 0 && !(val < new_expires)) { |
1da177e4 LT |
740 | /* |
741 | * The designated time already passed, so we notify | |
742 | * immediately, even if the thread never runs to | |
743 | * accumulate more time on this clock. | |
744 | */ | |
745 | cpu_timer_fire(timer); | |
746 | } | |
747 | ||
748 | ret = 0; | |
749 | out: | |
750 | if (old) { | |
751 | sample_to_timespec(timer->it_clock, | |
ae1a78ee | 752 | old_incr, &old->it_interval); |
1da177e4 | 753 | } |
a8572160 FW |
754 | if (!ret) |
755 | posix_cpu_timer_kick_nohz(); | |
1da177e4 LT |
756 | return ret; |
757 | } | |
758 | ||
bc2c8ea4 | 759 | static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp) |
1da177e4 | 760 | { |
55ccb616 | 761 | unsigned long long now; |
1da177e4 | 762 | struct task_struct *p = timer->it.cpu.task; |
1da177e4 | 763 | |
a3222f88 FW |
764 | WARN_ON_ONCE(p == NULL); |
765 | ||
1da177e4 LT |
766 | /* |
767 | * Easy part: convert the reload time. | |
768 | */ | |
769 | sample_to_timespec(timer->it_clock, | |
770 | timer->it.cpu.incr, &itp->it_interval); | |
771 | ||
55ccb616 | 772 | if (timer->it.cpu.expires == 0) { /* Timer not armed at all. */ |
1da177e4 LT |
773 | itp->it_value.tv_sec = itp->it_value.tv_nsec = 0; |
774 | return; | |
775 | } | |
776 | ||
1da177e4 LT |
777 | /* |
778 | * Sample the clock to take the difference with the expiry time. | |
779 | */ | |
780 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
781 | cpu_clock_sample(timer->it_clock, p, &now); | |
1da177e4 | 782 | } else { |
e73d84e3 FW |
783 | struct sighand_struct *sighand; |
784 | unsigned long flags; | |
785 | ||
786 | /* | |
787 | * Protect against sighand release/switch in exit/exec and | |
788 | * also make timer sampling safe if it ends up calling | |
789 | * thread_group_cputime(). | |
790 | */ | |
791 | sighand = lock_task_sighand(p, &flags); | |
792 | if (unlikely(sighand == NULL)) { | |
1da177e4 LT |
793 | /* |
794 | * The process has been reaped. | |
795 | * We can't even collect a sample any more. | |
796 | * Call the timer disarmed, nothing else to do. | |
797 | */ | |
55ccb616 | 798 | timer->it.cpu.expires = 0; |
a3222f88 FW |
799 | sample_to_timespec(timer->it_clock, timer->it.cpu.expires, |
800 | &itp->it_value); | |
1da177e4 | 801 | } else { |
3997ad31 | 802 | cpu_timer_sample_group(timer->it_clock, p, &now); |
e73d84e3 | 803 | unlock_task_sighand(p, &flags); |
1da177e4 | 804 | } |
1da177e4 LT |
805 | } |
806 | ||
55ccb616 | 807 | if (now < timer->it.cpu.expires) { |
1da177e4 | 808 | sample_to_timespec(timer->it_clock, |
55ccb616 | 809 | timer->it.cpu.expires - now, |
1da177e4 LT |
810 | &itp->it_value); |
811 | } else { | |
812 | /* | |
813 | * The timer should have expired already, but the firing | |
814 | * hasn't taken place yet. Say it's just about to expire. | |
815 | */ | |
816 | itp->it_value.tv_nsec = 1; | |
817 | itp->it_value.tv_sec = 0; | |
818 | } | |
819 | } | |
820 | ||
2473f3e7 FW |
821 | static unsigned long long |
822 | check_timers_list(struct list_head *timers, | |
823 | struct list_head *firing, | |
824 | unsigned long long curr) | |
825 | { | |
826 | int maxfire = 20; | |
827 | ||
828 | while (!list_empty(timers)) { | |
829 | struct cpu_timer_list *t; | |
830 | ||
831 | t = list_first_entry(timers, struct cpu_timer_list, entry); | |
832 | ||
833 | if (!--maxfire || curr < t->expires) | |
834 | return t->expires; | |
835 | ||
836 | t->firing = 1; | |
837 | list_move_tail(&t->entry, firing); | |
838 | } | |
839 | ||
840 | return 0; | |
841 | } | |
842 | ||
1da177e4 LT |
843 | /* |
844 | * Check for any per-thread CPU timers that have fired and move them off | |
845 | * the tsk->cpu_timers[N] list onto the firing list. Here we update the | |
846 | * tsk->it_*_expires values to reflect the remaining thread CPU timers. | |
847 | */ | |
848 | static void check_thread_timers(struct task_struct *tsk, | |
849 | struct list_head *firing) | |
850 | { | |
851 | struct list_head *timers = tsk->cpu_timers; | |
78f2c7db | 852 | struct signal_struct *const sig = tsk->signal; |
2473f3e7 FW |
853 | struct task_cputime *tsk_expires = &tsk->cputime_expires; |
854 | unsigned long long expires; | |
d4bb5274 | 855 | unsigned long soft; |
1da177e4 | 856 | |
2473f3e7 FW |
857 | expires = check_timers_list(timers, firing, prof_ticks(tsk)); |
858 | tsk_expires->prof_exp = expires_to_cputime(expires); | |
1da177e4 | 859 | |
2473f3e7 FW |
860 | expires = check_timers_list(++timers, firing, virt_ticks(tsk)); |
861 | tsk_expires->virt_exp = expires_to_cputime(expires); | |
1da177e4 | 862 | |
2473f3e7 FW |
863 | tsk_expires->sched_exp = check_timers_list(++timers, firing, |
864 | tsk->se.sum_exec_runtime); | |
78f2c7db PZ |
865 | |
866 | /* | |
867 | * Check for the special case thread timers. | |
868 | */ | |
78d7d407 | 869 | soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur); |
d4bb5274 | 870 | if (soft != RLIM_INFINITY) { |
78d7d407 JS |
871 | unsigned long hard = |
872 | ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max); | |
78f2c7db | 873 | |
5a52dd50 PZ |
874 | if (hard != RLIM_INFINITY && |
875 | tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { | |
78f2c7db PZ |
876 | /* |
877 | * At the hard limit, we just die. | |
878 | * No need to calculate anything else now. | |
879 | */ | |
880 | __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); | |
881 | return; | |
882 | } | |
d4bb5274 | 883 | if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { |
78f2c7db PZ |
884 | /* |
885 | * At the soft limit, send a SIGXCPU every second. | |
886 | */ | |
d4bb5274 JS |
887 | if (soft < hard) { |
888 | soft += USEC_PER_SEC; | |
889 | sig->rlim[RLIMIT_RTTIME].rlim_cur = soft; | |
78f2c7db | 890 | } |
81d50bb2 HS |
891 | printk(KERN_INFO |
892 | "RT Watchdog Timeout: %s[%d]\n", | |
893 | tsk->comm, task_pid_nr(tsk)); | |
78f2c7db PZ |
894 | __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); |
895 | } | |
896 | } | |
1da177e4 LT |
897 | } |
898 | ||
15365c10 | 899 | static void stop_process_timers(struct signal_struct *sig) |
3fccfd67 | 900 | { |
15365c10 | 901 | struct thread_group_cputimer *cputimer = &sig->cputimer; |
3fccfd67 PZ |
902 | unsigned long flags; |
903 | ||
ee30a7b2 | 904 | raw_spin_lock_irqsave(&cputimer->lock, flags); |
3fccfd67 | 905 | cputimer->running = 0; |
ee30a7b2 | 906 | raw_spin_unlock_irqrestore(&cputimer->lock, flags); |
3fccfd67 PZ |
907 | } |
908 | ||
8356b5f9 SG |
909 | static u32 onecputick; |
910 | ||
42c4ab41 | 911 | static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, |
55ccb616 FW |
912 | unsigned long long *expires, |
913 | unsigned long long cur_time, int signo) | |
42c4ab41 | 914 | { |
64861634 | 915 | if (!it->expires) |
42c4ab41 SG |
916 | return; |
917 | ||
64861634 MS |
918 | if (cur_time >= it->expires) { |
919 | if (it->incr) { | |
920 | it->expires += it->incr; | |
8356b5f9 SG |
921 | it->error += it->incr_error; |
922 | if (it->error >= onecputick) { | |
64861634 | 923 | it->expires -= cputime_one_jiffy; |
8356b5f9 SG |
924 | it->error -= onecputick; |
925 | } | |
3f0a525e | 926 | } else { |
64861634 | 927 | it->expires = 0; |
3f0a525e | 928 | } |
42c4ab41 | 929 | |
3f0a525e XG |
930 | trace_itimer_expire(signo == SIGPROF ? |
931 | ITIMER_PROF : ITIMER_VIRTUAL, | |
932 | tsk->signal->leader_pid, cur_time); | |
42c4ab41 SG |
933 | __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); |
934 | } | |
935 | ||
64861634 | 936 | if (it->expires && (!*expires || it->expires < *expires)) { |
42c4ab41 SG |
937 | *expires = it->expires; |
938 | } | |
939 | } | |
940 | ||
1da177e4 LT |
941 | /* |
942 | * Check for any per-thread CPU timers that have fired and move them | |
943 | * off the tsk->*_timers list onto the firing list. Per-thread timers | |
944 | * have already been taken off. | |
945 | */ | |
946 | static void check_process_timers(struct task_struct *tsk, | |
947 | struct list_head *firing) | |
948 | { | |
949 | struct signal_struct *const sig = tsk->signal; | |
55ccb616 | 950 | unsigned long long utime, ptime, virt_expires, prof_expires; |
41b86e9c | 951 | unsigned long long sum_sched_runtime, sched_expires; |
1da177e4 | 952 | struct list_head *timers = sig->cpu_timers; |
f06febc9 | 953 | struct task_cputime cputime; |
d4bb5274 | 954 | unsigned long soft; |
1da177e4 | 955 | |
1da177e4 LT |
956 | /* |
957 | * Collect the current process totals. | |
958 | */ | |
4cd4c1b4 | 959 | thread_group_cputimer(tsk, &cputime); |
55ccb616 FW |
960 | utime = cputime_to_expires(cputime.utime); |
961 | ptime = utime + cputime_to_expires(cputime.stime); | |
f06febc9 | 962 | sum_sched_runtime = cputime.sum_exec_runtime; |
1da177e4 | 963 | |
2473f3e7 FW |
964 | prof_expires = check_timers_list(timers, firing, ptime); |
965 | virt_expires = check_timers_list(++timers, firing, utime); | |
966 | sched_expires = check_timers_list(++timers, firing, sum_sched_runtime); | |
1da177e4 LT |
967 | |
968 | /* | |
969 | * Check for the special case process timers. | |
970 | */ | |
42c4ab41 SG |
971 | check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime, |
972 | SIGPROF); | |
973 | check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, | |
974 | SIGVTALRM); | |
78d7d407 | 975 | soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
d4bb5274 | 976 | if (soft != RLIM_INFINITY) { |
1da177e4 | 977 | unsigned long psecs = cputime_to_secs(ptime); |
78d7d407 JS |
978 | unsigned long hard = |
979 | ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max); | |
1da177e4 | 980 | cputime_t x; |
d4bb5274 | 981 | if (psecs >= hard) { |
1da177e4 LT |
982 | /* |
983 | * At the hard limit, we just die. | |
984 | * No need to calculate anything else now. | |
985 | */ | |
986 | __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); | |
987 | return; | |
988 | } | |
d4bb5274 | 989 | if (psecs >= soft) { |
1da177e4 LT |
990 | /* |
991 | * At the soft limit, send a SIGXCPU every second. | |
992 | */ | |
993 | __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); | |
d4bb5274 JS |
994 | if (soft < hard) { |
995 | soft++; | |
996 | sig->rlim[RLIMIT_CPU].rlim_cur = soft; | |
1da177e4 LT |
997 | } |
998 | } | |
d4bb5274 | 999 | x = secs_to_cputime(soft); |
64861634 | 1000 | if (!prof_expires || x < prof_expires) { |
1da177e4 LT |
1001 | prof_expires = x; |
1002 | } | |
1003 | } | |
1004 | ||
55ccb616 FW |
1005 | sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires); |
1006 | sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires); | |
29f87b79 SG |
1007 | sig->cputime_expires.sched_exp = sched_expires; |
1008 | if (task_cputime_zero(&sig->cputime_expires)) | |
1009 | stop_process_timers(sig); | |
1da177e4 LT |
1010 | } |
1011 | ||
1012 | /* | |
1013 | * This is called from the signal code (via do_schedule_next_timer) | |
1014 | * when the last timer signal was delivered and we have to reload the timer. | |
1015 | */ | |
1016 | void posix_cpu_timer_schedule(struct k_itimer *timer) | |
1017 | { | |
e73d84e3 FW |
1018 | struct sighand_struct *sighand; |
1019 | unsigned long flags; | |
1da177e4 | 1020 | struct task_struct *p = timer->it.cpu.task; |
55ccb616 | 1021 | unsigned long long now; |
1da177e4 | 1022 | |
a3222f88 | 1023 | WARN_ON_ONCE(p == NULL); |
1da177e4 LT |
1024 | |
1025 | /* | |
1026 | * Fetch the current sample and update the timer's expiry time. | |
1027 | */ | |
1028 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
1029 | cpu_clock_sample(timer->it_clock, p, &now); | |
1030 | bump_cpu_timer(timer, now); | |
724a3713 | 1031 | if (unlikely(p->exit_state)) |
708f430d | 1032 | goto out; |
724a3713 | 1033 | |
e73d84e3 FW |
1034 | /* Protect timer list r/w in arm_timer() */ |
1035 | sighand = lock_task_sighand(p, &flags); | |
1036 | if (!sighand) | |
1037 | goto out; | |
1da177e4 | 1038 | } else { |
e73d84e3 FW |
1039 | /* |
1040 | * Protect arm_timer() and timer sampling in case of call to | |
1041 | * thread_group_cputime(). | |
1042 | */ | |
1043 | sighand = lock_task_sighand(p, &flags); | |
1044 | if (unlikely(sighand == NULL)) { | |
1da177e4 LT |
1045 | /* |
1046 | * The process has been reaped. | |
1047 | * We can't even collect a sample any more. | |
1048 | */ | |
55ccb616 | 1049 | timer->it.cpu.expires = 0; |
c925077c | 1050 | goto out; |
1da177e4 | 1051 | } else if (unlikely(p->exit_state) && thread_group_empty(p)) { |
e73d84e3 | 1052 | unlock_task_sighand(p, &flags); |
d430b917 | 1053 | /* Optimizations: if the process is dying, no need to rearm */ |
c925077c | 1054 | goto out; |
1da177e4 | 1055 | } |
3997ad31 | 1056 | cpu_timer_sample_group(timer->it_clock, p, &now); |
1da177e4 | 1057 | bump_cpu_timer(timer, now); |
e73d84e3 | 1058 | /* Leave the sighand locked for the call below. */ |
1da177e4 LT |
1059 | } |
1060 | ||
1061 | /* | |
1062 | * Now re-arm for the new expiry time. | |
1063 | */ | |
531f64fd | 1064 | WARN_ON_ONCE(!irqs_disabled()); |
5eb9aa64 | 1065 | arm_timer(timer); |
e73d84e3 | 1066 | unlock_task_sighand(p, &flags); |
708f430d | 1067 | |
c925077c FW |
1068 | /* Kick full dynticks CPUs in case they need to tick on the new timer */ |
1069 | posix_cpu_timer_kick_nohz(); | |
708f430d RM |
1070 | out: |
1071 | timer->it_overrun_last = timer->it_overrun; | |
1072 | timer->it_overrun = -1; | |
1073 | ++timer->it_requeue_pending; | |
1da177e4 LT |
1074 | } |
1075 | ||
f06febc9 FM |
1076 | /** |
1077 | * task_cputime_expired - Compare two task_cputime entities. | |
1078 | * | |
1079 | * @sample: The task_cputime structure to be checked for expiration. | |
1080 | * @expires: Expiration times, against which @sample will be checked. | |
1081 | * | |
1082 | * Checks @sample against @expires to see if any field of @sample has expired. | |
1083 | * Returns true if any field of the former is greater than the corresponding | |
1084 | * field of the latter if the latter field is set. Otherwise returns false. | |
1085 | */ | |
1086 | static inline int task_cputime_expired(const struct task_cputime *sample, | |
1087 | const struct task_cputime *expires) | |
1088 | { | |
64861634 | 1089 | if (expires->utime && sample->utime >= expires->utime) |
f06febc9 | 1090 | return 1; |
64861634 | 1091 | if (expires->stime && sample->utime + sample->stime >= expires->stime) |
f06febc9 FM |
1092 | return 1; |
1093 | if (expires->sum_exec_runtime != 0 && | |
1094 | sample->sum_exec_runtime >= expires->sum_exec_runtime) | |
1095 | return 1; | |
1096 | return 0; | |
1097 | } | |
1098 | ||
1099 | /** | |
1100 | * fastpath_timer_check - POSIX CPU timers fast path. | |
1101 | * | |
1102 | * @tsk: The task (thread) being checked. | |
f06febc9 | 1103 | * |
bb34d92f FM |
1104 | * Check the task and thread group timers. If both are zero (there are no |
1105 | * timers set) return false. Otherwise snapshot the task and thread group | |
1106 | * timers and compare them with the corresponding expiration times. Return | |
1107 | * true if a timer has expired, else return false. | |
f06febc9 | 1108 | */ |
bb34d92f | 1109 | static inline int fastpath_timer_check(struct task_struct *tsk) |
f06febc9 | 1110 | { |
ad133ba3 | 1111 | struct signal_struct *sig; |
6fac4829 FW |
1112 | cputime_t utime, stime; |
1113 | ||
1114 | task_cputime(tsk, &utime, &stime); | |
bb34d92f | 1115 | |
bb34d92f FM |
1116 | if (!task_cputime_zero(&tsk->cputime_expires)) { |
1117 | struct task_cputime task_sample = { | |
6fac4829 FW |
1118 | .utime = utime, |
1119 | .stime = stime, | |
bb34d92f FM |
1120 | .sum_exec_runtime = tsk->se.sum_exec_runtime |
1121 | }; | |
1122 | ||
1123 | if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) | |
1124 | return 1; | |
1125 | } | |
ad133ba3 ON |
1126 | |
1127 | sig = tsk->signal; | |
29f87b79 | 1128 | if (sig->cputimer.running) { |
bb34d92f FM |
1129 | struct task_cputime group_sample; |
1130 | ||
ee30a7b2 | 1131 | raw_spin_lock(&sig->cputimer.lock); |
8d1f431c | 1132 | group_sample = sig->cputimer.cputime; |
ee30a7b2 | 1133 | raw_spin_unlock(&sig->cputimer.lock); |
8d1f431c | 1134 | |
bb34d92f FM |
1135 | if (task_cputime_expired(&group_sample, &sig->cputime_expires)) |
1136 | return 1; | |
1137 | } | |
37bebc70 | 1138 | |
f55db609 | 1139 | return 0; |
f06febc9 FM |
1140 | } |
1141 | ||
1da177e4 LT |
1142 | /* |
1143 | * This is called from the timer interrupt handler. The irq handler has | |
1144 | * already updated our counts. We need to check if any timers fire now. | |
1145 | * Interrupts are disabled. | |
1146 | */ | |
1147 | void run_posix_cpu_timers(struct task_struct *tsk) | |
1148 | { | |
1149 | LIST_HEAD(firing); | |
1150 | struct k_itimer *timer, *next; | |
0bdd2ed4 | 1151 | unsigned long flags; |
1da177e4 | 1152 | |
531f64fd | 1153 | WARN_ON_ONCE(!irqs_disabled()); |
1da177e4 | 1154 | |
1da177e4 | 1155 | /* |
f06febc9 | 1156 | * The fast path checks that there are no expired thread or thread |
bb34d92f | 1157 | * group timers. If that's so, just return. |
1da177e4 | 1158 | */ |
bb34d92f | 1159 | if (!fastpath_timer_check(tsk)) |
f06febc9 | 1160 | return; |
5ce73a4a | 1161 | |
0bdd2ed4 ON |
1162 | if (!lock_task_sighand(tsk, &flags)) |
1163 | return; | |
bb34d92f FM |
1164 | /* |
1165 | * Here we take off tsk->signal->cpu_timers[N] and | |
1166 | * tsk->cpu_timers[N] all the timers that are firing, and | |
1167 | * put them on the firing list. | |
1168 | */ | |
1169 | check_thread_timers(tsk, &firing); | |
29f87b79 SG |
1170 | /* |
1171 | * If there are any active process wide timers (POSIX 1.b, itimers, | |
1172 | * RLIMIT_CPU) cputimer must be running. | |
1173 | */ | |
1174 | if (tsk->signal->cputimer.running) | |
1175 | check_process_timers(tsk, &firing); | |
1da177e4 | 1176 | |
bb34d92f FM |
1177 | /* |
1178 | * We must release these locks before taking any timer's lock. | |
1179 | * There is a potential race with timer deletion here, as the | |
1180 | * siglock now protects our private firing list. We have set | |
1181 | * the firing flag in each timer, so that a deletion attempt | |
1182 | * that gets the timer lock before we do will give it up and | |
1183 | * spin until we've taken care of that timer below. | |
1184 | */ | |
0bdd2ed4 | 1185 | unlock_task_sighand(tsk, &flags); |
1da177e4 LT |
1186 | |
1187 | /* | |
1188 | * Now that all the timers on our list have the firing flag, | |
25985edc | 1189 | * no one will touch their list entries but us. We'll take |
1da177e4 LT |
1190 | * each timer's lock before clearing its firing flag, so no |
1191 | * timer call will interfere. | |
1192 | */ | |
1193 | list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) { | |
6e85c5ba HS |
1194 | int cpu_firing; |
1195 | ||
1da177e4 LT |
1196 | spin_lock(&timer->it_lock); |
1197 | list_del_init(&timer->it.cpu.entry); | |
6e85c5ba | 1198 | cpu_firing = timer->it.cpu.firing; |
1da177e4 LT |
1199 | timer->it.cpu.firing = 0; |
1200 | /* | |
1201 | * The firing flag is -1 if we collided with a reset | |
1202 | * of the timer, which already reported this | |
1203 | * almost-firing as an overrun. So don't generate an event. | |
1204 | */ | |
6e85c5ba | 1205 | if (likely(cpu_firing >= 0)) |
1da177e4 | 1206 | cpu_timer_fire(timer); |
1da177e4 LT |
1207 | spin_unlock(&timer->it_lock); |
1208 | } | |
1209 | } | |
1210 | ||
1211 | /* | |
f55db609 | 1212 | * Set one of the process-wide special case CPU timers or RLIMIT_CPU. |
f06febc9 | 1213 | * The tsk->sighand->siglock must be held by the caller. |
1da177e4 LT |
1214 | */ |
1215 | void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, | |
1216 | cputime_t *newval, cputime_t *oldval) | |
1217 | { | |
55ccb616 | 1218 | unsigned long long now; |
1da177e4 | 1219 | |
531f64fd | 1220 | WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED); |
4cd4c1b4 | 1221 | cpu_timer_sample_group(clock_idx, tsk, &now); |
1da177e4 LT |
1222 | |
1223 | if (oldval) { | |
f55db609 SG |
1224 | /* |
1225 | * We are setting itimer. The *oldval is absolute and we update | |
1226 | * it to be relative, *newval argument is relative and we update | |
1227 | * it to be absolute. | |
1228 | */ | |
64861634 | 1229 | if (*oldval) { |
55ccb616 | 1230 | if (*oldval <= now) { |
1da177e4 | 1231 | /* Just about to fire. */ |
a42548a1 | 1232 | *oldval = cputime_one_jiffy; |
1da177e4 | 1233 | } else { |
55ccb616 | 1234 | *oldval -= now; |
1da177e4 LT |
1235 | } |
1236 | } | |
1237 | ||
64861634 | 1238 | if (!*newval) |
a8572160 | 1239 | goto out; |
55ccb616 | 1240 | *newval += now; |
1da177e4 LT |
1241 | } |
1242 | ||
1243 | /* | |
f55db609 SG |
1244 | * Update expiration cache if we are the earliest timer, or eventually |
1245 | * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire. | |
1da177e4 | 1246 | */ |
f55db609 SG |
1247 | switch (clock_idx) { |
1248 | case CPUCLOCK_PROF: | |
1249 | if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval)) | |
f06febc9 | 1250 | tsk->signal->cputime_expires.prof_exp = *newval; |
f55db609 SG |
1251 | break; |
1252 | case CPUCLOCK_VIRT: | |
1253 | if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval)) | |
f06febc9 | 1254 | tsk->signal->cputime_expires.virt_exp = *newval; |
f55db609 | 1255 | break; |
1da177e4 | 1256 | } |
a8572160 FW |
1257 | out: |
1258 | posix_cpu_timer_kick_nohz(); | |
1da177e4 LT |
1259 | } |
1260 | ||
e4b76555 TA |
1261 | static int do_cpu_nanosleep(const clockid_t which_clock, int flags, |
1262 | struct timespec *rqtp, struct itimerspec *it) | |
1da177e4 | 1263 | { |
1da177e4 LT |
1264 | struct k_itimer timer; |
1265 | int error; | |
1266 | ||
1da177e4 LT |
1267 | /* |
1268 | * Set up a temporary timer and then wait for it to go off. | |
1269 | */ | |
1270 | memset(&timer, 0, sizeof timer); | |
1271 | spin_lock_init(&timer.it_lock); | |
1272 | timer.it_clock = which_clock; | |
1273 | timer.it_overrun = -1; | |
1274 | error = posix_cpu_timer_create(&timer); | |
1275 | timer.it_process = current; | |
1276 | if (!error) { | |
1da177e4 | 1277 | static struct itimerspec zero_it; |
e4b76555 TA |
1278 | |
1279 | memset(it, 0, sizeof *it); | |
1280 | it->it_value = *rqtp; | |
1da177e4 LT |
1281 | |
1282 | spin_lock_irq(&timer.it_lock); | |
e4b76555 | 1283 | error = posix_cpu_timer_set(&timer, flags, it, NULL); |
1da177e4 LT |
1284 | if (error) { |
1285 | spin_unlock_irq(&timer.it_lock); | |
1286 | return error; | |
1287 | } | |
1288 | ||
1289 | while (!signal_pending(current)) { | |
55ccb616 | 1290 | if (timer.it.cpu.expires == 0) { |
1da177e4 | 1291 | /* |
e6c42c29 SG |
1292 | * Our timer fired and was reset, below |
1293 | * deletion can not fail. | |
1da177e4 | 1294 | */ |
e6c42c29 | 1295 | posix_cpu_timer_del(&timer); |
1da177e4 LT |
1296 | spin_unlock_irq(&timer.it_lock); |
1297 | return 0; | |
1298 | } | |
1299 | ||
1300 | /* | |
1301 | * Block until cpu_timer_fire (or a signal) wakes us. | |
1302 | */ | |
1303 | __set_current_state(TASK_INTERRUPTIBLE); | |
1304 | spin_unlock_irq(&timer.it_lock); | |
1305 | schedule(); | |
1306 | spin_lock_irq(&timer.it_lock); | |
1307 | } | |
1308 | ||
1309 | /* | |
1310 | * We were interrupted by a signal. | |
1311 | */ | |
1312 | sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp); | |
e6c42c29 SG |
1313 | error = posix_cpu_timer_set(&timer, 0, &zero_it, it); |
1314 | if (!error) { | |
1315 | /* | |
1316 | * Timer is now unarmed, deletion can not fail. | |
1317 | */ | |
1318 | posix_cpu_timer_del(&timer); | |
1319 | } | |
1da177e4 LT |
1320 | spin_unlock_irq(&timer.it_lock); |
1321 | ||
e6c42c29 SG |
1322 | while (error == TIMER_RETRY) { |
1323 | /* | |
1324 | * We need to handle case when timer was or is in the | |
1325 | * middle of firing. In other cases we already freed | |
1326 | * resources. | |
1327 | */ | |
1328 | spin_lock_irq(&timer.it_lock); | |
1329 | error = posix_cpu_timer_del(&timer); | |
1330 | spin_unlock_irq(&timer.it_lock); | |
1331 | } | |
1332 | ||
e4b76555 | 1333 | if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) { |
1da177e4 LT |
1334 | /* |
1335 | * It actually did fire already. | |
1336 | */ | |
1337 | return 0; | |
1338 | } | |
1339 | ||
e4b76555 TA |
1340 | error = -ERESTART_RESTARTBLOCK; |
1341 | } | |
1342 | ||
1343 | return error; | |
1344 | } | |
1345 | ||
bc2c8ea4 TG |
1346 | static long posix_cpu_nsleep_restart(struct restart_block *restart_block); |
1347 | ||
1348 | static int posix_cpu_nsleep(const clockid_t which_clock, int flags, | |
1349 | struct timespec *rqtp, struct timespec __user *rmtp) | |
e4b76555 TA |
1350 | { |
1351 | struct restart_block *restart_block = | |
3751f9f2 | 1352 | ¤t_thread_info()->restart_block; |
e4b76555 TA |
1353 | struct itimerspec it; |
1354 | int error; | |
1355 | ||
1356 | /* | |
1357 | * Diagnose required errors first. | |
1358 | */ | |
1359 | if (CPUCLOCK_PERTHREAD(which_clock) && | |
1360 | (CPUCLOCK_PID(which_clock) == 0 || | |
1361 | CPUCLOCK_PID(which_clock) == current->pid)) | |
1362 | return -EINVAL; | |
1363 | ||
1364 | error = do_cpu_nanosleep(which_clock, flags, rqtp, &it); | |
1365 | ||
1366 | if (error == -ERESTART_RESTARTBLOCK) { | |
1367 | ||
3751f9f2 | 1368 | if (flags & TIMER_ABSTIME) |
e4b76555 | 1369 | return -ERESTARTNOHAND; |
1da177e4 | 1370 | /* |
3751f9f2 TG |
1371 | * Report back to the user the time still remaining. |
1372 | */ | |
1373 | if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp)) | |
1da177e4 LT |
1374 | return -EFAULT; |
1375 | ||
1711ef38 | 1376 | restart_block->fn = posix_cpu_nsleep_restart; |
ab8177bc | 1377 | restart_block->nanosleep.clockid = which_clock; |
3751f9f2 TG |
1378 | restart_block->nanosleep.rmtp = rmtp; |
1379 | restart_block->nanosleep.expires = timespec_to_ns(rqtp); | |
1da177e4 | 1380 | } |
1da177e4 LT |
1381 | return error; |
1382 | } | |
1383 | ||
bc2c8ea4 | 1384 | static long posix_cpu_nsleep_restart(struct restart_block *restart_block) |
1da177e4 | 1385 | { |
ab8177bc | 1386 | clockid_t which_clock = restart_block->nanosleep.clockid; |
97735f25 | 1387 | struct timespec t; |
e4b76555 TA |
1388 | struct itimerspec it; |
1389 | int error; | |
97735f25 | 1390 | |
3751f9f2 | 1391 | t = ns_to_timespec(restart_block->nanosleep.expires); |
97735f25 | 1392 | |
e4b76555 TA |
1393 | error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it); |
1394 | ||
1395 | if (error == -ERESTART_RESTARTBLOCK) { | |
3751f9f2 | 1396 | struct timespec __user *rmtp = restart_block->nanosleep.rmtp; |
e4b76555 | 1397 | /* |
3751f9f2 TG |
1398 | * Report back to the user the time still remaining. |
1399 | */ | |
1400 | if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp)) | |
e4b76555 TA |
1401 | return -EFAULT; |
1402 | ||
3751f9f2 | 1403 | restart_block->nanosleep.expires = timespec_to_ns(&t); |
e4b76555 TA |
1404 | } |
1405 | return error; | |
1406 | ||
1da177e4 LT |
1407 | } |
1408 | ||
1da177e4 LT |
1409 | #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED) |
1410 | #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED) | |
1411 | ||
a924b04d TG |
1412 | static int process_cpu_clock_getres(const clockid_t which_clock, |
1413 | struct timespec *tp) | |
1da177e4 LT |
1414 | { |
1415 | return posix_cpu_clock_getres(PROCESS_CLOCK, tp); | |
1416 | } | |
a924b04d TG |
1417 | static int process_cpu_clock_get(const clockid_t which_clock, |
1418 | struct timespec *tp) | |
1da177e4 LT |
1419 | { |
1420 | return posix_cpu_clock_get(PROCESS_CLOCK, tp); | |
1421 | } | |
1422 | static int process_cpu_timer_create(struct k_itimer *timer) | |
1423 | { | |
1424 | timer->it_clock = PROCESS_CLOCK; | |
1425 | return posix_cpu_timer_create(timer); | |
1426 | } | |
a924b04d | 1427 | static int process_cpu_nsleep(const clockid_t which_clock, int flags, |
97735f25 TG |
1428 | struct timespec *rqtp, |
1429 | struct timespec __user *rmtp) | |
1da177e4 | 1430 | { |
97735f25 | 1431 | return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp); |
1da177e4 | 1432 | } |
1711ef38 TA |
1433 | static long process_cpu_nsleep_restart(struct restart_block *restart_block) |
1434 | { | |
1435 | return -EINVAL; | |
1436 | } | |
a924b04d TG |
1437 | static int thread_cpu_clock_getres(const clockid_t which_clock, |
1438 | struct timespec *tp) | |
1da177e4 LT |
1439 | { |
1440 | return posix_cpu_clock_getres(THREAD_CLOCK, tp); | |
1441 | } | |
a924b04d TG |
1442 | static int thread_cpu_clock_get(const clockid_t which_clock, |
1443 | struct timespec *tp) | |
1da177e4 LT |
1444 | { |
1445 | return posix_cpu_clock_get(THREAD_CLOCK, tp); | |
1446 | } | |
1447 | static int thread_cpu_timer_create(struct k_itimer *timer) | |
1448 | { | |
1449 | timer->it_clock = THREAD_CLOCK; | |
1450 | return posix_cpu_timer_create(timer); | |
1451 | } | |
1da177e4 | 1452 | |
1976945e TG |
1453 | struct k_clock clock_posix_cpu = { |
1454 | .clock_getres = posix_cpu_clock_getres, | |
1455 | .clock_set = posix_cpu_clock_set, | |
1456 | .clock_get = posix_cpu_clock_get, | |
1457 | .timer_create = posix_cpu_timer_create, | |
1458 | .nsleep = posix_cpu_nsleep, | |
1459 | .nsleep_restart = posix_cpu_nsleep_restart, | |
1460 | .timer_set = posix_cpu_timer_set, | |
1461 | .timer_del = posix_cpu_timer_del, | |
1462 | .timer_get = posix_cpu_timer_get, | |
1463 | }; | |
1464 | ||
1da177e4 LT |
1465 | static __init int init_posix_cpu_timers(void) |
1466 | { | |
1467 | struct k_clock process = { | |
2fd1f040 TG |
1468 | .clock_getres = process_cpu_clock_getres, |
1469 | .clock_get = process_cpu_clock_get, | |
2fd1f040 TG |
1470 | .timer_create = process_cpu_timer_create, |
1471 | .nsleep = process_cpu_nsleep, | |
1472 | .nsleep_restart = process_cpu_nsleep_restart, | |
1da177e4 LT |
1473 | }; |
1474 | struct k_clock thread = { | |
2fd1f040 TG |
1475 | .clock_getres = thread_cpu_clock_getres, |
1476 | .clock_get = thread_cpu_clock_get, | |
2fd1f040 | 1477 | .timer_create = thread_cpu_timer_create, |
1da177e4 | 1478 | }; |
8356b5f9 | 1479 | struct timespec ts; |
1da177e4 | 1480 | |
52708737 TG |
1481 | posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process); |
1482 | posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread); | |
1da177e4 | 1483 | |
a42548a1 | 1484 | cputime_to_timespec(cputime_one_jiffy, &ts); |
8356b5f9 SG |
1485 | onecputick = ts.tv_nsec; |
1486 | WARN_ON(ts.tv_sec != 0); | |
1487 | ||
1da177e4 LT |
1488 | return 0; |
1489 | } | |
1490 | __initcall(init_posix_cpu_timers); |