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. | |
236 | * Must be called with tasklist_lock held for reading. | |
1da177e4 | 237 | */ |
bb34d92f FM |
238 | static int cpu_clock_sample_group(const clockid_t which_clock, |
239 | struct task_struct *p, | |
55ccb616 | 240 | unsigned long long *sample) |
1da177e4 | 241 | { |
f06febc9 FM |
242 | struct task_cputime cputime; |
243 | ||
eccdaeaf | 244 | switch (CPUCLOCK_WHICH(which_clock)) { |
1da177e4 LT |
245 | default: |
246 | return -EINVAL; | |
247 | case CPUCLOCK_PROF: | |
c5f8d995 | 248 | thread_group_cputime(p, &cputime); |
55ccb616 | 249 | *sample = cputime_to_expires(cputime.utime + cputime.stime); |
1da177e4 LT |
250 | break; |
251 | case CPUCLOCK_VIRT: | |
c5f8d995 | 252 | thread_group_cputime(p, &cputime); |
55ccb616 | 253 | *sample = cputime_to_expires(cputime.utime); |
1da177e4 LT |
254 | break; |
255 | case CPUCLOCK_SCHED: | |
d670ec13 | 256 | thread_group_cputime(p, &cputime); |
55ccb616 | 257 | *sample = cputime.sum_exec_runtime; |
1da177e4 LT |
258 | break; |
259 | } | |
260 | return 0; | |
261 | } | |
262 | ||
33ab0fec FW |
263 | static int posix_cpu_clock_get_task(struct task_struct *tsk, |
264 | const clockid_t which_clock, | |
265 | struct timespec *tp) | |
266 | { | |
267 | int err = -EINVAL; | |
268 | unsigned long long rtn; | |
269 | ||
270 | if (CPUCLOCK_PERTHREAD(which_clock)) { | |
271 | if (same_thread_group(tsk, current)) | |
272 | err = cpu_clock_sample(which_clock, tsk, &rtn); | |
273 | } else { | |
50875788 FW |
274 | unsigned long flags; |
275 | struct sighand_struct *sighand; | |
33ab0fec | 276 | |
50875788 FW |
277 | /* |
278 | * while_each_thread() is not yet entirely RCU safe, | |
279 | * keep locking the group while sampling process | |
280 | * clock for now. | |
281 | */ | |
282 | sighand = lock_task_sighand(tsk, &flags); | |
283 | if (!sighand) | |
284 | return err; | |
285 | ||
286 | if (tsk == current || thread_group_leader(tsk)) | |
33ab0fec FW |
287 | err = cpu_clock_sample_group(which_clock, tsk, &rtn); |
288 | ||
50875788 | 289 | unlock_task_sighand(tsk, &flags); |
33ab0fec FW |
290 | } |
291 | ||
292 | if (!err) | |
293 | sample_to_timespec(which_clock, rtn, tp); | |
294 | ||
295 | return err; | |
296 | } | |
297 | ||
1da177e4 | 298 | |
bc2c8ea4 | 299 | static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp) |
1da177e4 LT |
300 | { |
301 | const pid_t pid = CPUCLOCK_PID(which_clock); | |
33ab0fec | 302 | int err = -EINVAL; |
1da177e4 LT |
303 | |
304 | if (pid == 0) { | |
305 | /* | |
306 | * Special case constant value for our own clocks. | |
307 | * We don't have to do any lookup to find ourselves. | |
308 | */ | |
33ab0fec | 309 | err = posix_cpu_clock_get_task(current, which_clock, tp); |
1da177e4 LT |
310 | } else { |
311 | /* | |
312 | * Find the given PID, and validate that the caller | |
313 | * should be able to see it. | |
314 | */ | |
315 | struct task_struct *p; | |
1f2ea083 | 316 | rcu_read_lock(); |
8dc86af0 | 317 | p = find_task_by_vpid(pid); |
33ab0fec FW |
318 | if (p) |
319 | err = posix_cpu_clock_get_task(p, which_clock, tp); | |
1f2ea083 | 320 | rcu_read_unlock(); |
1da177e4 LT |
321 | } |
322 | ||
33ab0fec | 323 | return err; |
1da177e4 LT |
324 | } |
325 | ||
326 | ||
327 | /* | |
328 | * Validate the clockid_t for a new CPU-clock timer, and initialize the timer. | |
ba5ea951 SG |
329 | * This is called from sys_timer_create() and do_cpu_nanosleep() with the |
330 | * new timer already all-zeros initialized. | |
1da177e4 | 331 | */ |
bc2c8ea4 | 332 | static int posix_cpu_timer_create(struct k_itimer *new_timer) |
1da177e4 LT |
333 | { |
334 | int ret = 0; | |
335 | const pid_t pid = CPUCLOCK_PID(new_timer->it_clock); | |
336 | struct task_struct *p; | |
337 | ||
338 | if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX) | |
339 | return -EINVAL; | |
340 | ||
341 | INIT_LIST_HEAD(&new_timer->it.cpu.entry); | |
1da177e4 | 342 | |
c0deae8c | 343 | rcu_read_lock(); |
1da177e4 LT |
344 | if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) { |
345 | if (pid == 0) { | |
346 | p = current; | |
347 | } else { | |
8dc86af0 | 348 | p = find_task_by_vpid(pid); |
bac0abd6 | 349 | if (p && !same_thread_group(p, current)) |
1da177e4 LT |
350 | p = NULL; |
351 | } | |
352 | } else { | |
353 | if (pid == 0) { | |
354 | p = current->group_leader; | |
355 | } else { | |
8dc86af0 | 356 | p = find_task_by_vpid(pid); |
c0deae8c | 357 | if (p && !has_group_leader_pid(p)) |
1da177e4 LT |
358 | p = NULL; |
359 | } | |
360 | } | |
361 | new_timer->it.cpu.task = p; | |
362 | if (p) { | |
363 | get_task_struct(p); | |
364 | } else { | |
365 | ret = -EINVAL; | |
366 | } | |
c0deae8c | 367 | rcu_read_unlock(); |
1da177e4 LT |
368 | |
369 | return ret; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Clean up a CPU-clock timer that is about to be destroyed. | |
374 | * This is called from timer deletion with the timer already locked. | |
375 | * If we return TIMER_RETRY, it's necessary to release the timer's lock | |
376 | * and try again. (This happens when the timer is in the middle of firing.) | |
377 | */ | |
bc2c8ea4 | 378 | static int posix_cpu_timer_del(struct k_itimer *timer) |
1da177e4 LT |
379 | { |
380 | struct task_struct *p = timer->it.cpu.task; | |
108150ea | 381 | int ret = 0; |
1da177e4 | 382 | |
a3222f88 | 383 | WARN_ON_ONCE(p == NULL); |
108150ea | 384 | |
a3222f88 FW |
385 | read_lock(&tasklist_lock); |
386 | if (unlikely(p->sighand == NULL)) { | |
387 | /* | |
388 | * We raced with the reaping of the task. | |
389 | * The deletion should have cleared us off the list. | |
390 | */ | |
391 | BUG_ON(!list_empty(&timer->it.cpu.entry)); | |
392 | } else { | |
393 | spin_lock(&p->sighand->siglock); | |
394 | if (timer->it.cpu.firing) | |
395 | ret = TIMER_RETRY; | |
396 | else | |
397 | list_del(&timer->it.cpu.entry); | |
398 | spin_unlock(&p->sighand->siglock); | |
1da177e4 | 399 | } |
a3222f88 FW |
400 | read_unlock(&tasklist_lock); |
401 | ||
402 | if (!ret) | |
403 | put_task_struct(p); | |
1da177e4 | 404 | |
108150ea | 405 | return ret; |
1da177e4 LT |
406 | } |
407 | ||
af82eb3c | 408 | static void cleanup_timers_list(struct list_head *head) |
1a7fa510 FW |
409 | { |
410 | struct cpu_timer_list *timer, *next; | |
411 | ||
a0b2062b | 412 | list_for_each_entry_safe(timer, next, head, entry) |
1a7fa510 | 413 | list_del_init(&timer->entry); |
1a7fa510 FW |
414 | } |
415 | ||
1da177e4 LT |
416 | /* |
417 | * Clean out CPU timers still ticking when a thread exited. The task | |
418 | * pointer is cleared, and the expiry time is replaced with the residual | |
419 | * time for later timer_gettime calls to return. | |
420 | * This must be called with the siglock held. | |
421 | */ | |
af82eb3c | 422 | static void cleanup_timers(struct list_head *head) |
1da177e4 | 423 | { |
af82eb3c FW |
424 | cleanup_timers_list(head); |
425 | cleanup_timers_list(++head); | |
426 | cleanup_timers_list(++head); | |
1da177e4 LT |
427 | } |
428 | ||
429 | /* | |
430 | * These are both called with the siglock held, when the current thread | |
431 | * is being reaped. When the final (leader) thread in the group is reaped, | |
432 | * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit. | |
433 | */ | |
434 | void posix_cpu_timers_exit(struct task_struct *tsk) | |
435 | { | |
61337054 NK |
436 | add_device_randomness((const void*) &tsk->se.sum_exec_runtime, |
437 | sizeof(unsigned long long)); | |
af82eb3c | 438 | cleanup_timers(tsk->cpu_timers); |
1da177e4 LT |
439 | |
440 | } | |
441 | void posix_cpu_timers_exit_group(struct task_struct *tsk) | |
442 | { | |
af82eb3c | 443 | cleanup_timers(tsk->signal->cpu_timers); |
1da177e4 LT |
444 | } |
445 | ||
d1e3b6d1 SG |
446 | static inline int expires_gt(cputime_t expires, cputime_t new_exp) |
447 | { | |
64861634 | 448 | return expires == 0 || expires > new_exp; |
d1e3b6d1 SG |
449 | } |
450 | ||
1da177e4 LT |
451 | /* |
452 | * Insert the timer on the appropriate list before any timers that | |
453 | * expire later. This must be called with the tasklist_lock held | |
c2873937 | 454 | * for reading, interrupts disabled and p->sighand->siglock taken. |
1da177e4 | 455 | */ |
5eb9aa64 | 456 | static void arm_timer(struct k_itimer *timer) |
1da177e4 LT |
457 | { |
458 | struct task_struct *p = timer->it.cpu.task; | |
459 | struct list_head *head, *listpos; | |
5eb9aa64 | 460 | struct task_cputime *cputime_expires; |
1da177e4 LT |
461 | struct cpu_timer_list *const nt = &timer->it.cpu; |
462 | struct cpu_timer_list *next; | |
1da177e4 | 463 | |
5eb9aa64 SG |
464 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { |
465 | head = p->cpu_timers; | |
466 | cputime_expires = &p->cputime_expires; | |
467 | } else { | |
468 | head = p->signal->cpu_timers; | |
469 | cputime_expires = &p->signal->cputime_expires; | |
470 | } | |
1da177e4 LT |
471 | head += CPUCLOCK_WHICH(timer->it_clock); |
472 | ||
1da177e4 | 473 | listpos = head; |
5eb9aa64 | 474 | list_for_each_entry(next, head, entry) { |
55ccb616 | 475 | if (nt->expires < next->expires) |
5eb9aa64 SG |
476 | break; |
477 | listpos = &next->entry; | |
1da177e4 LT |
478 | } |
479 | list_add(&nt->entry, listpos); | |
480 | ||
481 | if (listpos == head) { | |
55ccb616 | 482 | unsigned long long exp = nt->expires; |
5eb9aa64 | 483 | |
1da177e4 | 484 | /* |
5eb9aa64 SG |
485 | * We are the new earliest-expiring POSIX 1.b timer, hence |
486 | * need to update expiration cache. Take into account that | |
487 | * for process timers we share expiration cache with itimers | |
488 | * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME. | |
1da177e4 LT |
489 | */ |
490 | ||
5eb9aa64 SG |
491 | switch (CPUCLOCK_WHICH(timer->it_clock)) { |
492 | case CPUCLOCK_PROF: | |
55ccb616 FW |
493 | if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp))) |
494 | cputime_expires->prof_exp = expires_to_cputime(exp); | |
5eb9aa64 SG |
495 | break; |
496 | case CPUCLOCK_VIRT: | |
55ccb616 FW |
497 | if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp))) |
498 | cputime_expires->virt_exp = expires_to_cputime(exp); | |
5eb9aa64 SG |
499 | break; |
500 | case CPUCLOCK_SCHED: | |
501 | if (cputime_expires->sched_exp == 0 || | |
55ccb616 FW |
502 | cputime_expires->sched_exp > exp) |
503 | cputime_expires->sched_exp = exp; | |
5eb9aa64 | 504 | break; |
1da177e4 LT |
505 | } |
506 | } | |
1da177e4 LT |
507 | } |
508 | ||
509 | /* | |
510 | * The timer is locked, fire it and arrange for its reload. | |
511 | */ | |
512 | static void cpu_timer_fire(struct k_itimer *timer) | |
513 | { | |
1f169f84 SG |
514 | if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { |
515 | /* | |
516 | * User don't want any signal. | |
517 | */ | |
55ccb616 | 518 | timer->it.cpu.expires = 0; |
1f169f84 | 519 | } else if (unlikely(timer->sigq == NULL)) { |
1da177e4 LT |
520 | /* |
521 | * This a special case for clock_nanosleep, | |
522 | * not a normal timer from sys_timer_create. | |
523 | */ | |
524 | wake_up_process(timer->it_process); | |
55ccb616 FW |
525 | timer->it.cpu.expires = 0; |
526 | } else if (timer->it.cpu.incr == 0) { | |
1da177e4 LT |
527 | /* |
528 | * One-shot timer. Clear it as soon as it's fired. | |
529 | */ | |
530 | posix_timer_event(timer, 0); | |
55ccb616 | 531 | timer->it.cpu.expires = 0; |
1da177e4 LT |
532 | } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) { |
533 | /* | |
534 | * The signal did not get queued because the signal | |
535 | * was ignored, so we won't get any callback to | |
536 | * reload the timer. But we need to keep it | |
537 | * ticking in case the signal is deliverable next time. | |
538 | */ | |
539 | posix_cpu_timer_schedule(timer); | |
540 | } | |
541 | } | |
542 | ||
3997ad31 PZ |
543 | /* |
544 | * Sample a process (thread group) timer for the given group_leader task. | |
545 | * Must be called with tasklist_lock held for reading. | |
546 | */ | |
547 | static int cpu_timer_sample_group(const clockid_t which_clock, | |
548 | struct task_struct *p, | |
55ccb616 | 549 | unsigned long long *sample) |
3997ad31 PZ |
550 | { |
551 | struct task_cputime cputime; | |
552 | ||
553 | thread_group_cputimer(p, &cputime); | |
554 | switch (CPUCLOCK_WHICH(which_clock)) { | |
555 | default: | |
556 | return -EINVAL; | |
557 | case CPUCLOCK_PROF: | |
55ccb616 | 558 | *sample = cputime_to_expires(cputime.utime + cputime.stime); |
3997ad31 PZ |
559 | break; |
560 | case CPUCLOCK_VIRT: | |
55ccb616 | 561 | *sample = cputime_to_expires(cputime.utime); |
3997ad31 PZ |
562 | break; |
563 | case CPUCLOCK_SCHED: | |
55ccb616 | 564 | *sample = cputime.sum_exec_runtime + task_delta_exec(p); |
3997ad31 PZ |
565 | break; |
566 | } | |
567 | return 0; | |
568 | } | |
569 | ||
a8572160 FW |
570 | #ifdef CONFIG_NO_HZ_FULL |
571 | static void nohz_kick_work_fn(struct work_struct *work) | |
572 | { | |
573 | tick_nohz_full_kick_all(); | |
574 | } | |
575 | ||
576 | static DECLARE_WORK(nohz_kick_work, nohz_kick_work_fn); | |
577 | ||
578 | /* | |
579 | * We need the IPIs to be sent from sane process context. | |
580 | * The posix cpu timers are always set with irqs disabled. | |
581 | */ | |
582 | static void posix_cpu_timer_kick_nohz(void) | |
583 | { | |
d4283c65 FW |
584 | if (context_tracking_is_enabled()) |
585 | schedule_work(&nohz_kick_work); | |
a8572160 | 586 | } |
555347f6 FW |
587 | |
588 | bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk) | |
589 | { | |
590 | if (!task_cputime_zero(&tsk->cputime_expires)) | |
6ac29178 | 591 | return false; |
555347f6 FW |
592 | |
593 | if (tsk->signal->cputimer.running) | |
6ac29178 | 594 | return false; |
555347f6 | 595 | |
6ac29178 | 596 | return true; |
555347f6 | 597 | } |
a8572160 FW |
598 | #else |
599 | static inline void posix_cpu_timer_kick_nohz(void) { } | |
600 | #endif | |
601 | ||
1da177e4 LT |
602 | /* |
603 | * Guts of sys_timer_settime for CPU timers. | |
604 | * This is called with the timer locked and interrupts disabled. | |
605 | * If we return TIMER_RETRY, it's necessary to release the timer's lock | |
606 | * and try again. (This happens when the timer is in the middle of firing.) | |
607 | */ | |
bc2c8ea4 TG |
608 | static int posix_cpu_timer_set(struct k_itimer *timer, int flags, |
609 | struct itimerspec *new, struct itimerspec *old) | |
1da177e4 LT |
610 | { |
611 | struct task_struct *p = timer->it.cpu.task; | |
55ccb616 | 612 | unsigned long long old_expires, new_expires, old_incr, val; |
1da177e4 LT |
613 | int ret; |
614 | ||
a3222f88 | 615 | WARN_ON_ONCE(p == NULL); |
1da177e4 LT |
616 | |
617 | new_expires = timespec_to_sample(timer->it_clock, &new->it_value); | |
618 | ||
619 | read_lock(&tasklist_lock); | |
620 | /* | |
621 | * We need the tasklist_lock to protect against reaping that | |
d30fda35 | 622 | * clears p->sighand. If p has just been reaped, we can no |
1da177e4 LT |
623 | * longer get any information about it at all. |
624 | */ | |
d30fda35 | 625 | if (unlikely(p->sighand == NULL)) { |
1da177e4 | 626 | read_unlock(&tasklist_lock); |
1da177e4 LT |
627 | return -ESRCH; |
628 | } | |
629 | ||
630 | /* | |
631 | * Disarm any old timer after extracting its expiry time. | |
632 | */ | |
633 | BUG_ON(!irqs_disabled()); | |
a69ac4a7 ON |
634 | |
635 | ret = 0; | |
ae1a78ee | 636 | old_incr = timer->it.cpu.incr; |
1da177e4 LT |
637 | spin_lock(&p->sighand->siglock); |
638 | old_expires = timer->it.cpu.expires; | |
a69ac4a7 ON |
639 | if (unlikely(timer->it.cpu.firing)) { |
640 | timer->it.cpu.firing = -1; | |
641 | ret = TIMER_RETRY; | |
642 | } else | |
643 | list_del_init(&timer->it.cpu.entry); | |
1da177e4 LT |
644 | |
645 | /* | |
646 | * We need to sample the current value to convert the new | |
647 | * value from to relative and absolute, and to convert the | |
648 | * old value from absolute to relative. To set a process | |
649 | * timer, we need a sample to balance the thread expiry | |
650 | * times (in arm_timer). With an absolute time, we must | |
651 | * check if it's already passed. In short, we need a sample. | |
652 | */ | |
653 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
654 | cpu_clock_sample(timer->it_clock, p, &val); | |
655 | } else { | |
3997ad31 | 656 | cpu_timer_sample_group(timer->it_clock, p, &val); |
1da177e4 LT |
657 | } |
658 | ||
659 | if (old) { | |
55ccb616 | 660 | if (old_expires == 0) { |
1da177e4 LT |
661 | old->it_value.tv_sec = 0; |
662 | old->it_value.tv_nsec = 0; | |
663 | } else { | |
664 | /* | |
665 | * Update the timer in case it has | |
666 | * overrun already. If it has, | |
667 | * we'll report it as having overrun | |
668 | * and with the next reloaded timer | |
669 | * already ticking, though we are | |
670 | * swallowing that pending | |
671 | * notification here to install the | |
672 | * new setting. | |
673 | */ | |
674 | bump_cpu_timer(timer, val); | |
55ccb616 FW |
675 | if (val < timer->it.cpu.expires) { |
676 | old_expires = timer->it.cpu.expires - val; | |
1da177e4 LT |
677 | sample_to_timespec(timer->it_clock, |
678 | old_expires, | |
679 | &old->it_value); | |
680 | } else { | |
681 | old->it_value.tv_nsec = 1; | |
682 | old->it_value.tv_sec = 0; | |
683 | } | |
684 | } | |
685 | } | |
686 | ||
a69ac4a7 | 687 | if (unlikely(ret)) { |
1da177e4 LT |
688 | /* |
689 | * We are colliding with the timer actually firing. | |
690 | * Punt after filling in the timer's old value, and | |
691 | * disable this firing since we are already reporting | |
692 | * it as an overrun (thanks to bump_cpu_timer above). | |
693 | */ | |
c2873937 | 694 | spin_unlock(&p->sighand->siglock); |
1da177e4 | 695 | read_unlock(&tasklist_lock); |
1da177e4 LT |
696 | goto out; |
697 | } | |
698 | ||
55ccb616 FW |
699 | if (new_expires != 0 && !(flags & TIMER_ABSTIME)) { |
700 | new_expires += val; | |
1da177e4 LT |
701 | } |
702 | ||
703 | /* | |
704 | * Install the new expiry time (or zero). | |
705 | * For a timer with no notification action, we don't actually | |
706 | * arm the timer (we'll just fake it for timer_gettime). | |
707 | */ | |
708 | timer->it.cpu.expires = new_expires; | |
55ccb616 | 709 | if (new_expires != 0 && val < new_expires) { |
5eb9aa64 | 710 | arm_timer(timer); |
1da177e4 LT |
711 | } |
712 | ||
c2873937 | 713 | spin_unlock(&p->sighand->siglock); |
1da177e4 LT |
714 | read_unlock(&tasklist_lock); |
715 | ||
716 | /* | |
717 | * Install the new reload setting, and | |
718 | * set up the signal and overrun bookkeeping. | |
719 | */ | |
720 | timer->it.cpu.incr = timespec_to_sample(timer->it_clock, | |
721 | &new->it_interval); | |
722 | ||
723 | /* | |
724 | * This acts as a modification timestamp for the timer, | |
725 | * so any automatic reload attempt will punt on seeing | |
726 | * that we have reset the timer manually. | |
727 | */ | |
728 | timer->it_requeue_pending = (timer->it_requeue_pending + 2) & | |
729 | ~REQUEUE_PENDING; | |
730 | timer->it_overrun_last = 0; | |
731 | timer->it_overrun = -1; | |
732 | ||
55ccb616 | 733 | if (new_expires != 0 && !(val < new_expires)) { |
1da177e4 LT |
734 | /* |
735 | * The designated time already passed, so we notify | |
736 | * immediately, even if the thread never runs to | |
737 | * accumulate more time on this clock. | |
738 | */ | |
739 | cpu_timer_fire(timer); | |
740 | } | |
741 | ||
742 | ret = 0; | |
743 | out: | |
744 | if (old) { | |
745 | sample_to_timespec(timer->it_clock, | |
ae1a78ee | 746 | old_incr, &old->it_interval); |
1da177e4 | 747 | } |
a8572160 FW |
748 | if (!ret) |
749 | posix_cpu_timer_kick_nohz(); | |
1da177e4 LT |
750 | return ret; |
751 | } | |
752 | ||
bc2c8ea4 | 753 | static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp) |
1da177e4 | 754 | { |
55ccb616 | 755 | unsigned long long now; |
1da177e4 | 756 | struct task_struct *p = timer->it.cpu.task; |
1da177e4 | 757 | |
a3222f88 FW |
758 | WARN_ON_ONCE(p == NULL); |
759 | ||
1da177e4 LT |
760 | /* |
761 | * Easy part: convert the reload time. | |
762 | */ | |
763 | sample_to_timespec(timer->it_clock, | |
764 | timer->it.cpu.incr, &itp->it_interval); | |
765 | ||
55ccb616 | 766 | if (timer->it.cpu.expires == 0) { /* Timer not armed at all. */ |
1da177e4 LT |
767 | itp->it_value.tv_sec = itp->it_value.tv_nsec = 0; |
768 | return; | |
769 | } | |
770 | ||
1da177e4 LT |
771 | /* |
772 | * Sample the clock to take the difference with the expiry time. | |
773 | */ | |
774 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
775 | cpu_clock_sample(timer->it_clock, p, &now); | |
1da177e4 LT |
776 | } else { |
777 | read_lock(&tasklist_lock); | |
d30fda35 | 778 | if (unlikely(p->sighand == NULL)) { |
1da177e4 LT |
779 | /* |
780 | * The process has been reaped. | |
781 | * We can't even collect a sample any more. | |
782 | * Call the timer disarmed, nothing else to do. | |
783 | */ | |
55ccb616 | 784 | timer->it.cpu.expires = 0; |
a3222f88 FW |
785 | sample_to_timespec(timer->it_clock, timer->it.cpu.expires, |
786 | &itp->it_value); | |
1da177e4 | 787 | read_unlock(&tasklist_lock); |
1da177e4 | 788 | } else { |
3997ad31 | 789 | cpu_timer_sample_group(timer->it_clock, p, &now); |
1da177e4 LT |
790 | } |
791 | read_unlock(&tasklist_lock); | |
792 | } | |
793 | ||
55ccb616 | 794 | if (now < timer->it.cpu.expires) { |
1da177e4 | 795 | sample_to_timespec(timer->it_clock, |
55ccb616 | 796 | timer->it.cpu.expires - now, |
1da177e4 LT |
797 | &itp->it_value); |
798 | } else { | |
799 | /* | |
800 | * The timer should have expired already, but the firing | |
801 | * hasn't taken place yet. Say it's just about to expire. | |
802 | */ | |
803 | itp->it_value.tv_nsec = 1; | |
804 | itp->it_value.tv_sec = 0; | |
805 | } | |
806 | } | |
807 | ||
2473f3e7 FW |
808 | static unsigned long long |
809 | check_timers_list(struct list_head *timers, | |
810 | struct list_head *firing, | |
811 | unsigned long long curr) | |
812 | { | |
813 | int maxfire = 20; | |
814 | ||
815 | while (!list_empty(timers)) { | |
816 | struct cpu_timer_list *t; | |
817 | ||
818 | t = list_first_entry(timers, struct cpu_timer_list, entry); | |
819 | ||
820 | if (!--maxfire || curr < t->expires) | |
821 | return t->expires; | |
822 | ||
823 | t->firing = 1; | |
824 | list_move_tail(&t->entry, firing); | |
825 | } | |
826 | ||
827 | return 0; | |
828 | } | |
829 | ||
1da177e4 LT |
830 | /* |
831 | * Check for any per-thread CPU timers that have fired and move them off | |
832 | * the tsk->cpu_timers[N] list onto the firing list. Here we update the | |
833 | * tsk->it_*_expires values to reflect the remaining thread CPU timers. | |
834 | */ | |
835 | static void check_thread_timers(struct task_struct *tsk, | |
836 | struct list_head *firing) | |
837 | { | |
838 | struct list_head *timers = tsk->cpu_timers; | |
78f2c7db | 839 | struct signal_struct *const sig = tsk->signal; |
2473f3e7 FW |
840 | struct task_cputime *tsk_expires = &tsk->cputime_expires; |
841 | unsigned long long expires; | |
d4bb5274 | 842 | unsigned long soft; |
1da177e4 | 843 | |
2473f3e7 FW |
844 | expires = check_timers_list(timers, firing, prof_ticks(tsk)); |
845 | tsk_expires->prof_exp = expires_to_cputime(expires); | |
1da177e4 | 846 | |
2473f3e7 FW |
847 | expires = check_timers_list(++timers, firing, virt_ticks(tsk)); |
848 | tsk_expires->virt_exp = expires_to_cputime(expires); | |
1da177e4 | 849 | |
2473f3e7 FW |
850 | tsk_expires->sched_exp = check_timers_list(++timers, firing, |
851 | tsk->se.sum_exec_runtime); | |
78f2c7db PZ |
852 | |
853 | /* | |
854 | * Check for the special case thread timers. | |
855 | */ | |
78d7d407 | 856 | soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur); |
d4bb5274 | 857 | if (soft != RLIM_INFINITY) { |
78d7d407 JS |
858 | unsigned long hard = |
859 | ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max); | |
78f2c7db | 860 | |
5a52dd50 PZ |
861 | if (hard != RLIM_INFINITY && |
862 | tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { | |
78f2c7db PZ |
863 | /* |
864 | * At the hard limit, we just die. | |
865 | * No need to calculate anything else now. | |
866 | */ | |
867 | __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); | |
868 | return; | |
869 | } | |
d4bb5274 | 870 | if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { |
78f2c7db PZ |
871 | /* |
872 | * At the soft limit, send a SIGXCPU every second. | |
873 | */ | |
d4bb5274 JS |
874 | if (soft < hard) { |
875 | soft += USEC_PER_SEC; | |
876 | sig->rlim[RLIMIT_RTTIME].rlim_cur = soft; | |
78f2c7db | 877 | } |
81d50bb2 HS |
878 | printk(KERN_INFO |
879 | "RT Watchdog Timeout: %s[%d]\n", | |
880 | tsk->comm, task_pid_nr(tsk)); | |
78f2c7db PZ |
881 | __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); |
882 | } | |
883 | } | |
1da177e4 LT |
884 | } |
885 | ||
15365c10 | 886 | static void stop_process_timers(struct signal_struct *sig) |
3fccfd67 | 887 | { |
15365c10 | 888 | struct thread_group_cputimer *cputimer = &sig->cputimer; |
3fccfd67 PZ |
889 | unsigned long flags; |
890 | ||
ee30a7b2 | 891 | raw_spin_lock_irqsave(&cputimer->lock, flags); |
3fccfd67 | 892 | cputimer->running = 0; |
ee30a7b2 | 893 | raw_spin_unlock_irqrestore(&cputimer->lock, flags); |
3fccfd67 PZ |
894 | } |
895 | ||
8356b5f9 SG |
896 | static u32 onecputick; |
897 | ||
42c4ab41 | 898 | static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, |
55ccb616 FW |
899 | unsigned long long *expires, |
900 | unsigned long long cur_time, int signo) | |
42c4ab41 | 901 | { |
64861634 | 902 | if (!it->expires) |
42c4ab41 SG |
903 | return; |
904 | ||
64861634 MS |
905 | if (cur_time >= it->expires) { |
906 | if (it->incr) { | |
907 | it->expires += it->incr; | |
8356b5f9 SG |
908 | it->error += it->incr_error; |
909 | if (it->error >= onecputick) { | |
64861634 | 910 | it->expires -= cputime_one_jiffy; |
8356b5f9 SG |
911 | it->error -= onecputick; |
912 | } | |
3f0a525e | 913 | } else { |
64861634 | 914 | it->expires = 0; |
3f0a525e | 915 | } |
42c4ab41 | 916 | |
3f0a525e XG |
917 | trace_itimer_expire(signo == SIGPROF ? |
918 | ITIMER_PROF : ITIMER_VIRTUAL, | |
919 | tsk->signal->leader_pid, cur_time); | |
42c4ab41 SG |
920 | __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); |
921 | } | |
922 | ||
64861634 | 923 | if (it->expires && (!*expires || it->expires < *expires)) { |
42c4ab41 SG |
924 | *expires = it->expires; |
925 | } | |
926 | } | |
927 | ||
1da177e4 LT |
928 | /* |
929 | * Check for any per-thread CPU timers that have fired and move them | |
930 | * off the tsk->*_timers list onto the firing list. Per-thread timers | |
931 | * have already been taken off. | |
932 | */ | |
933 | static void check_process_timers(struct task_struct *tsk, | |
934 | struct list_head *firing) | |
935 | { | |
936 | struct signal_struct *const sig = tsk->signal; | |
55ccb616 | 937 | unsigned long long utime, ptime, virt_expires, prof_expires; |
41b86e9c | 938 | unsigned long long sum_sched_runtime, sched_expires; |
1da177e4 | 939 | struct list_head *timers = sig->cpu_timers; |
f06febc9 | 940 | struct task_cputime cputime; |
d4bb5274 | 941 | unsigned long soft; |
1da177e4 | 942 | |
1da177e4 LT |
943 | /* |
944 | * Collect the current process totals. | |
945 | */ | |
4cd4c1b4 | 946 | thread_group_cputimer(tsk, &cputime); |
55ccb616 FW |
947 | utime = cputime_to_expires(cputime.utime); |
948 | ptime = utime + cputime_to_expires(cputime.stime); | |
f06febc9 | 949 | sum_sched_runtime = cputime.sum_exec_runtime; |
1da177e4 | 950 | |
2473f3e7 FW |
951 | prof_expires = check_timers_list(timers, firing, ptime); |
952 | virt_expires = check_timers_list(++timers, firing, utime); | |
953 | sched_expires = check_timers_list(++timers, firing, sum_sched_runtime); | |
1da177e4 LT |
954 | |
955 | /* | |
956 | * Check for the special case process timers. | |
957 | */ | |
42c4ab41 SG |
958 | check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime, |
959 | SIGPROF); | |
960 | check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, | |
961 | SIGVTALRM); | |
78d7d407 | 962 | soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
d4bb5274 | 963 | if (soft != RLIM_INFINITY) { |
1da177e4 | 964 | unsigned long psecs = cputime_to_secs(ptime); |
78d7d407 JS |
965 | unsigned long hard = |
966 | ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max); | |
1da177e4 | 967 | cputime_t x; |
d4bb5274 | 968 | if (psecs >= hard) { |
1da177e4 LT |
969 | /* |
970 | * At the hard limit, we just die. | |
971 | * No need to calculate anything else now. | |
972 | */ | |
973 | __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); | |
974 | return; | |
975 | } | |
d4bb5274 | 976 | if (psecs >= soft) { |
1da177e4 LT |
977 | /* |
978 | * At the soft limit, send a SIGXCPU every second. | |
979 | */ | |
980 | __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); | |
d4bb5274 JS |
981 | if (soft < hard) { |
982 | soft++; | |
983 | sig->rlim[RLIMIT_CPU].rlim_cur = soft; | |
1da177e4 LT |
984 | } |
985 | } | |
d4bb5274 | 986 | x = secs_to_cputime(soft); |
64861634 | 987 | if (!prof_expires || x < prof_expires) { |
1da177e4 LT |
988 | prof_expires = x; |
989 | } | |
990 | } | |
991 | ||
55ccb616 FW |
992 | sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires); |
993 | sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires); | |
29f87b79 SG |
994 | sig->cputime_expires.sched_exp = sched_expires; |
995 | if (task_cputime_zero(&sig->cputime_expires)) | |
996 | stop_process_timers(sig); | |
1da177e4 LT |
997 | } |
998 | ||
999 | /* | |
1000 | * This is called from the signal code (via do_schedule_next_timer) | |
1001 | * when the last timer signal was delivered and we have to reload the timer. | |
1002 | */ | |
1003 | void posix_cpu_timer_schedule(struct k_itimer *timer) | |
1004 | { | |
1005 | struct task_struct *p = timer->it.cpu.task; | |
55ccb616 | 1006 | unsigned long long now; |
1da177e4 | 1007 | |
a3222f88 | 1008 | WARN_ON_ONCE(p == NULL); |
1da177e4 LT |
1009 | |
1010 | /* | |
1011 | * Fetch the current sample and update the timer's expiry time. | |
1012 | */ | |
1013 | if (CPUCLOCK_PERTHREAD(timer->it_clock)) { | |
1014 | cpu_clock_sample(timer->it_clock, p, &now); | |
1015 | bump_cpu_timer(timer, now); | |
724a3713 | 1016 | if (unlikely(p->exit_state)) |
708f430d | 1017 | goto out; |
724a3713 | 1018 | |
1da177e4 | 1019 | read_lock(&tasklist_lock); /* arm_timer needs it. */ |
c2873937 | 1020 | spin_lock(&p->sighand->siglock); |
1da177e4 LT |
1021 | } else { |
1022 | read_lock(&tasklist_lock); | |
d30fda35 | 1023 | if (unlikely(p->sighand == NULL)) { |
1da177e4 LT |
1024 | /* |
1025 | * The process has been reaped. | |
1026 | * We can't even collect a sample any more. | |
1027 | */ | |
55ccb616 | 1028 | timer->it.cpu.expires = 0; |
c925077c FW |
1029 | read_unlock(&tasklist_lock); |
1030 | goto out; | |
1da177e4 | 1031 | } else if (unlikely(p->exit_state) && thread_group_empty(p)) { |
c925077c | 1032 | read_unlock(&tasklist_lock); |
d430b917 | 1033 | /* Optimizations: if the process is dying, no need to rearm */ |
c925077c | 1034 | goto out; |
1da177e4 | 1035 | } |
c2873937 | 1036 | spin_lock(&p->sighand->siglock); |
3997ad31 | 1037 | cpu_timer_sample_group(timer->it_clock, p, &now); |
1da177e4 LT |
1038 | bump_cpu_timer(timer, now); |
1039 | /* Leave the tasklist_lock locked for the call below. */ | |
1040 | } | |
1041 | ||
1042 | /* | |
1043 | * Now re-arm for the new expiry time. | |
1044 | */ | |
c2873937 | 1045 | BUG_ON(!irqs_disabled()); |
5eb9aa64 | 1046 | arm_timer(timer); |
c2873937 | 1047 | spin_unlock(&p->sighand->siglock); |
1da177e4 | 1048 | read_unlock(&tasklist_lock); |
708f430d | 1049 | |
c925077c FW |
1050 | /* Kick full dynticks CPUs in case they need to tick on the new timer */ |
1051 | posix_cpu_timer_kick_nohz(); | |
1052 | ||
708f430d RM |
1053 | out: |
1054 | timer->it_overrun_last = timer->it_overrun; | |
1055 | timer->it_overrun = -1; | |
1056 | ++timer->it_requeue_pending; | |
1da177e4 LT |
1057 | } |
1058 | ||
f06febc9 FM |
1059 | /** |
1060 | * task_cputime_expired - Compare two task_cputime entities. | |
1061 | * | |
1062 | * @sample: The task_cputime structure to be checked for expiration. | |
1063 | * @expires: Expiration times, against which @sample will be checked. | |
1064 | * | |
1065 | * Checks @sample against @expires to see if any field of @sample has expired. | |
1066 | * Returns true if any field of the former is greater than the corresponding | |
1067 | * field of the latter if the latter field is set. Otherwise returns false. | |
1068 | */ | |
1069 | static inline int task_cputime_expired(const struct task_cputime *sample, | |
1070 | const struct task_cputime *expires) | |
1071 | { | |
64861634 | 1072 | if (expires->utime && sample->utime >= expires->utime) |
f06febc9 | 1073 | return 1; |
64861634 | 1074 | if (expires->stime && sample->utime + sample->stime >= expires->stime) |
f06febc9 FM |
1075 | return 1; |
1076 | if (expires->sum_exec_runtime != 0 && | |
1077 | sample->sum_exec_runtime >= expires->sum_exec_runtime) | |
1078 | return 1; | |
1079 | return 0; | |
1080 | } | |
1081 | ||
1082 | /** | |
1083 | * fastpath_timer_check - POSIX CPU timers fast path. | |
1084 | * | |
1085 | * @tsk: The task (thread) being checked. | |
f06febc9 | 1086 | * |
bb34d92f FM |
1087 | * Check the task and thread group timers. If both are zero (there are no |
1088 | * timers set) return false. Otherwise snapshot the task and thread group | |
1089 | * timers and compare them with the corresponding expiration times. Return | |
1090 | * true if a timer has expired, else return false. | |
f06febc9 | 1091 | */ |
bb34d92f | 1092 | static inline int fastpath_timer_check(struct task_struct *tsk) |
f06febc9 | 1093 | { |
ad133ba3 | 1094 | struct signal_struct *sig; |
6fac4829 FW |
1095 | cputime_t utime, stime; |
1096 | ||
1097 | task_cputime(tsk, &utime, &stime); | |
bb34d92f | 1098 | |
bb34d92f FM |
1099 | if (!task_cputime_zero(&tsk->cputime_expires)) { |
1100 | struct task_cputime task_sample = { | |
6fac4829 FW |
1101 | .utime = utime, |
1102 | .stime = stime, | |
bb34d92f FM |
1103 | .sum_exec_runtime = tsk->se.sum_exec_runtime |
1104 | }; | |
1105 | ||
1106 | if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) | |
1107 | return 1; | |
1108 | } | |
ad133ba3 ON |
1109 | |
1110 | sig = tsk->signal; | |
29f87b79 | 1111 | if (sig->cputimer.running) { |
bb34d92f FM |
1112 | struct task_cputime group_sample; |
1113 | ||
ee30a7b2 | 1114 | raw_spin_lock(&sig->cputimer.lock); |
8d1f431c | 1115 | group_sample = sig->cputimer.cputime; |
ee30a7b2 | 1116 | raw_spin_unlock(&sig->cputimer.lock); |
8d1f431c | 1117 | |
bb34d92f FM |
1118 | if (task_cputime_expired(&group_sample, &sig->cputime_expires)) |
1119 | return 1; | |
1120 | } | |
37bebc70 | 1121 | |
f55db609 | 1122 | return 0; |
f06febc9 FM |
1123 | } |
1124 | ||
1da177e4 LT |
1125 | /* |
1126 | * This is called from the timer interrupt handler. The irq handler has | |
1127 | * already updated our counts. We need to check if any timers fire now. | |
1128 | * Interrupts are disabled. | |
1129 | */ | |
1130 | void run_posix_cpu_timers(struct task_struct *tsk) | |
1131 | { | |
1132 | LIST_HEAD(firing); | |
1133 | struct k_itimer *timer, *next; | |
0bdd2ed4 | 1134 | unsigned long flags; |
1da177e4 LT |
1135 | |
1136 | BUG_ON(!irqs_disabled()); | |
1137 | ||
1da177e4 | 1138 | /* |
f06febc9 | 1139 | * The fast path checks that there are no expired thread or thread |
bb34d92f | 1140 | * group timers. If that's so, just return. |
1da177e4 | 1141 | */ |
bb34d92f | 1142 | if (!fastpath_timer_check(tsk)) |
f06febc9 | 1143 | return; |
5ce73a4a | 1144 | |
0bdd2ed4 ON |
1145 | if (!lock_task_sighand(tsk, &flags)) |
1146 | return; | |
bb34d92f FM |
1147 | /* |
1148 | * Here we take off tsk->signal->cpu_timers[N] and | |
1149 | * tsk->cpu_timers[N] all the timers that are firing, and | |
1150 | * put them on the firing list. | |
1151 | */ | |
1152 | check_thread_timers(tsk, &firing); | |
29f87b79 SG |
1153 | /* |
1154 | * If there are any active process wide timers (POSIX 1.b, itimers, | |
1155 | * RLIMIT_CPU) cputimer must be running. | |
1156 | */ | |
1157 | if (tsk->signal->cputimer.running) | |
1158 | check_process_timers(tsk, &firing); | |
1da177e4 | 1159 | |
bb34d92f FM |
1160 | /* |
1161 | * We must release these locks before taking any timer's lock. | |
1162 | * There is a potential race with timer deletion here, as the | |
1163 | * siglock now protects our private firing list. We have set | |
1164 | * the firing flag in each timer, so that a deletion attempt | |
1165 | * that gets the timer lock before we do will give it up and | |
1166 | * spin until we've taken care of that timer below. | |
1167 | */ | |
0bdd2ed4 | 1168 | unlock_task_sighand(tsk, &flags); |
1da177e4 LT |
1169 | |
1170 | /* | |
1171 | * Now that all the timers on our list have the firing flag, | |
25985edc | 1172 | * no one will touch their list entries but us. We'll take |
1da177e4 LT |
1173 | * each timer's lock before clearing its firing flag, so no |
1174 | * timer call will interfere. | |
1175 | */ | |
1176 | list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) { | |
6e85c5ba HS |
1177 | int cpu_firing; |
1178 | ||
1da177e4 LT |
1179 | spin_lock(&timer->it_lock); |
1180 | list_del_init(&timer->it.cpu.entry); | |
6e85c5ba | 1181 | cpu_firing = timer->it.cpu.firing; |
1da177e4 LT |
1182 | timer->it.cpu.firing = 0; |
1183 | /* | |
1184 | * The firing flag is -1 if we collided with a reset | |
1185 | * of the timer, which already reported this | |
1186 | * almost-firing as an overrun. So don't generate an event. | |
1187 | */ | |
6e85c5ba | 1188 | if (likely(cpu_firing >= 0)) |
1da177e4 | 1189 | cpu_timer_fire(timer); |
1da177e4 LT |
1190 | spin_unlock(&timer->it_lock); |
1191 | } | |
1192 | } | |
1193 | ||
1194 | /* | |
f55db609 | 1195 | * Set one of the process-wide special case CPU timers or RLIMIT_CPU. |
f06febc9 | 1196 | * The tsk->sighand->siglock must be held by the caller. |
1da177e4 LT |
1197 | */ |
1198 | void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, | |
1199 | cputime_t *newval, cputime_t *oldval) | |
1200 | { | |
55ccb616 | 1201 | unsigned long long now; |
1da177e4 LT |
1202 | |
1203 | BUG_ON(clock_idx == CPUCLOCK_SCHED); | |
4cd4c1b4 | 1204 | cpu_timer_sample_group(clock_idx, tsk, &now); |
1da177e4 LT |
1205 | |
1206 | if (oldval) { | |
f55db609 SG |
1207 | /* |
1208 | * We are setting itimer. The *oldval is absolute and we update | |
1209 | * it to be relative, *newval argument is relative and we update | |
1210 | * it to be absolute. | |
1211 | */ | |
64861634 | 1212 | if (*oldval) { |
55ccb616 | 1213 | if (*oldval <= now) { |
1da177e4 | 1214 | /* Just about to fire. */ |
a42548a1 | 1215 | *oldval = cputime_one_jiffy; |
1da177e4 | 1216 | } else { |
55ccb616 | 1217 | *oldval -= now; |
1da177e4 LT |
1218 | } |
1219 | } | |
1220 | ||
64861634 | 1221 | if (!*newval) |
a8572160 | 1222 | goto out; |
55ccb616 | 1223 | *newval += now; |
1da177e4 LT |
1224 | } |
1225 | ||
1226 | /* | |
f55db609 SG |
1227 | * Update expiration cache if we are the earliest timer, or eventually |
1228 | * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire. | |
1da177e4 | 1229 | */ |
f55db609 SG |
1230 | switch (clock_idx) { |
1231 | case CPUCLOCK_PROF: | |
1232 | if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval)) | |
f06febc9 | 1233 | tsk->signal->cputime_expires.prof_exp = *newval; |
f55db609 SG |
1234 | break; |
1235 | case CPUCLOCK_VIRT: | |
1236 | if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval)) | |
f06febc9 | 1237 | tsk->signal->cputime_expires.virt_exp = *newval; |
f55db609 | 1238 | break; |
1da177e4 | 1239 | } |
a8572160 FW |
1240 | out: |
1241 | posix_cpu_timer_kick_nohz(); | |
1da177e4 LT |
1242 | } |
1243 | ||
e4b76555 TA |
1244 | static int do_cpu_nanosleep(const clockid_t which_clock, int flags, |
1245 | struct timespec *rqtp, struct itimerspec *it) | |
1da177e4 | 1246 | { |
1da177e4 LT |
1247 | struct k_itimer timer; |
1248 | int error; | |
1249 | ||
1da177e4 LT |
1250 | /* |
1251 | * Set up a temporary timer and then wait for it to go off. | |
1252 | */ | |
1253 | memset(&timer, 0, sizeof timer); | |
1254 | spin_lock_init(&timer.it_lock); | |
1255 | timer.it_clock = which_clock; | |
1256 | timer.it_overrun = -1; | |
1257 | error = posix_cpu_timer_create(&timer); | |
1258 | timer.it_process = current; | |
1259 | if (!error) { | |
1da177e4 | 1260 | static struct itimerspec zero_it; |
e4b76555 TA |
1261 | |
1262 | memset(it, 0, sizeof *it); | |
1263 | it->it_value = *rqtp; | |
1da177e4 LT |
1264 | |
1265 | spin_lock_irq(&timer.it_lock); | |
e4b76555 | 1266 | error = posix_cpu_timer_set(&timer, flags, it, NULL); |
1da177e4 LT |
1267 | if (error) { |
1268 | spin_unlock_irq(&timer.it_lock); | |
1269 | return error; | |
1270 | } | |
1271 | ||
1272 | while (!signal_pending(current)) { | |
55ccb616 | 1273 | if (timer.it.cpu.expires == 0) { |
1da177e4 | 1274 | /* |
e6c42c29 SG |
1275 | * Our timer fired and was reset, below |
1276 | * deletion can not fail. | |
1da177e4 | 1277 | */ |
e6c42c29 | 1278 | posix_cpu_timer_del(&timer); |
1da177e4 LT |
1279 | spin_unlock_irq(&timer.it_lock); |
1280 | return 0; | |
1281 | } | |
1282 | ||
1283 | /* | |
1284 | * Block until cpu_timer_fire (or a signal) wakes us. | |
1285 | */ | |
1286 | __set_current_state(TASK_INTERRUPTIBLE); | |
1287 | spin_unlock_irq(&timer.it_lock); | |
1288 | schedule(); | |
1289 | spin_lock_irq(&timer.it_lock); | |
1290 | } | |
1291 | ||
1292 | /* | |
1293 | * We were interrupted by a signal. | |
1294 | */ | |
1295 | sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp); | |
e6c42c29 SG |
1296 | error = posix_cpu_timer_set(&timer, 0, &zero_it, it); |
1297 | if (!error) { | |
1298 | /* | |
1299 | * Timer is now unarmed, deletion can not fail. | |
1300 | */ | |
1301 | posix_cpu_timer_del(&timer); | |
1302 | } | |
1da177e4 LT |
1303 | spin_unlock_irq(&timer.it_lock); |
1304 | ||
e6c42c29 SG |
1305 | while (error == TIMER_RETRY) { |
1306 | /* | |
1307 | * We need to handle case when timer was or is in the | |
1308 | * middle of firing. In other cases we already freed | |
1309 | * resources. | |
1310 | */ | |
1311 | spin_lock_irq(&timer.it_lock); | |
1312 | error = posix_cpu_timer_del(&timer); | |
1313 | spin_unlock_irq(&timer.it_lock); | |
1314 | } | |
1315 | ||
e4b76555 | 1316 | if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) { |
1da177e4 LT |
1317 | /* |
1318 | * It actually did fire already. | |
1319 | */ | |
1320 | return 0; | |
1321 | } | |
1322 | ||
e4b76555 TA |
1323 | error = -ERESTART_RESTARTBLOCK; |
1324 | } | |
1325 | ||
1326 | return error; | |
1327 | } | |
1328 | ||
bc2c8ea4 TG |
1329 | static long posix_cpu_nsleep_restart(struct restart_block *restart_block); |
1330 | ||
1331 | static int posix_cpu_nsleep(const clockid_t which_clock, int flags, | |
1332 | struct timespec *rqtp, struct timespec __user *rmtp) | |
e4b76555 TA |
1333 | { |
1334 | struct restart_block *restart_block = | |
3751f9f2 | 1335 | ¤t_thread_info()->restart_block; |
e4b76555 TA |
1336 | struct itimerspec it; |
1337 | int error; | |
1338 | ||
1339 | /* | |
1340 | * Diagnose required errors first. | |
1341 | */ | |
1342 | if (CPUCLOCK_PERTHREAD(which_clock) && | |
1343 | (CPUCLOCK_PID(which_clock) == 0 || | |
1344 | CPUCLOCK_PID(which_clock) == current->pid)) | |
1345 | return -EINVAL; | |
1346 | ||
1347 | error = do_cpu_nanosleep(which_clock, flags, rqtp, &it); | |
1348 | ||
1349 | if (error == -ERESTART_RESTARTBLOCK) { | |
1350 | ||
3751f9f2 | 1351 | if (flags & TIMER_ABSTIME) |
e4b76555 | 1352 | return -ERESTARTNOHAND; |
1da177e4 | 1353 | /* |
3751f9f2 TG |
1354 | * Report back to the user the time still remaining. |
1355 | */ | |
1356 | if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp)) | |
1da177e4 LT |
1357 | return -EFAULT; |
1358 | ||
1711ef38 | 1359 | restart_block->fn = posix_cpu_nsleep_restart; |
ab8177bc | 1360 | restart_block->nanosleep.clockid = which_clock; |
3751f9f2 TG |
1361 | restart_block->nanosleep.rmtp = rmtp; |
1362 | restart_block->nanosleep.expires = timespec_to_ns(rqtp); | |
1da177e4 | 1363 | } |
1da177e4 LT |
1364 | return error; |
1365 | } | |
1366 | ||
bc2c8ea4 | 1367 | static long posix_cpu_nsleep_restart(struct restart_block *restart_block) |
1da177e4 | 1368 | { |
ab8177bc | 1369 | clockid_t which_clock = restart_block->nanosleep.clockid; |
97735f25 | 1370 | struct timespec t; |
e4b76555 TA |
1371 | struct itimerspec it; |
1372 | int error; | |
97735f25 | 1373 | |
3751f9f2 | 1374 | t = ns_to_timespec(restart_block->nanosleep.expires); |
97735f25 | 1375 | |
e4b76555 TA |
1376 | error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it); |
1377 | ||
1378 | if (error == -ERESTART_RESTARTBLOCK) { | |
3751f9f2 | 1379 | struct timespec __user *rmtp = restart_block->nanosleep.rmtp; |
e4b76555 | 1380 | /* |
3751f9f2 TG |
1381 | * Report back to the user the time still remaining. |
1382 | */ | |
1383 | if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp)) | |
e4b76555 TA |
1384 | return -EFAULT; |
1385 | ||
3751f9f2 | 1386 | restart_block->nanosleep.expires = timespec_to_ns(&t); |
e4b76555 TA |
1387 | } |
1388 | return error; | |
1389 | ||
1da177e4 LT |
1390 | } |
1391 | ||
1da177e4 LT |
1392 | #define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED) |
1393 | #define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED) | |
1394 | ||
a924b04d TG |
1395 | static int process_cpu_clock_getres(const clockid_t which_clock, |
1396 | struct timespec *tp) | |
1da177e4 LT |
1397 | { |
1398 | return posix_cpu_clock_getres(PROCESS_CLOCK, tp); | |
1399 | } | |
a924b04d TG |
1400 | static int process_cpu_clock_get(const clockid_t which_clock, |
1401 | struct timespec *tp) | |
1da177e4 LT |
1402 | { |
1403 | return posix_cpu_clock_get(PROCESS_CLOCK, tp); | |
1404 | } | |
1405 | static int process_cpu_timer_create(struct k_itimer *timer) | |
1406 | { | |
1407 | timer->it_clock = PROCESS_CLOCK; | |
1408 | return posix_cpu_timer_create(timer); | |
1409 | } | |
a924b04d | 1410 | static int process_cpu_nsleep(const clockid_t which_clock, int flags, |
97735f25 TG |
1411 | struct timespec *rqtp, |
1412 | struct timespec __user *rmtp) | |
1da177e4 | 1413 | { |
97735f25 | 1414 | return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp); |
1da177e4 | 1415 | } |
1711ef38 TA |
1416 | static long process_cpu_nsleep_restart(struct restart_block *restart_block) |
1417 | { | |
1418 | return -EINVAL; | |
1419 | } | |
a924b04d TG |
1420 | static int thread_cpu_clock_getres(const clockid_t which_clock, |
1421 | struct timespec *tp) | |
1da177e4 LT |
1422 | { |
1423 | return posix_cpu_clock_getres(THREAD_CLOCK, tp); | |
1424 | } | |
a924b04d TG |
1425 | static int thread_cpu_clock_get(const clockid_t which_clock, |
1426 | struct timespec *tp) | |
1da177e4 LT |
1427 | { |
1428 | return posix_cpu_clock_get(THREAD_CLOCK, tp); | |
1429 | } | |
1430 | static int thread_cpu_timer_create(struct k_itimer *timer) | |
1431 | { | |
1432 | timer->it_clock = THREAD_CLOCK; | |
1433 | return posix_cpu_timer_create(timer); | |
1434 | } | |
1da177e4 | 1435 | |
1976945e TG |
1436 | struct k_clock clock_posix_cpu = { |
1437 | .clock_getres = posix_cpu_clock_getres, | |
1438 | .clock_set = posix_cpu_clock_set, | |
1439 | .clock_get = posix_cpu_clock_get, | |
1440 | .timer_create = posix_cpu_timer_create, | |
1441 | .nsleep = posix_cpu_nsleep, | |
1442 | .nsleep_restart = posix_cpu_nsleep_restart, | |
1443 | .timer_set = posix_cpu_timer_set, | |
1444 | .timer_del = posix_cpu_timer_del, | |
1445 | .timer_get = posix_cpu_timer_get, | |
1446 | }; | |
1447 | ||
1da177e4 LT |
1448 | static __init int init_posix_cpu_timers(void) |
1449 | { | |
1450 | struct k_clock process = { | |
2fd1f040 TG |
1451 | .clock_getres = process_cpu_clock_getres, |
1452 | .clock_get = process_cpu_clock_get, | |
2fd1f040 TG |
1453 | .timer_create = process_cpu_timer_create, |
1454 | .nsleep = process_cpu_nsleep, | |
1455 | .nsleep_restart = process_cpu_nsleep_restart, | |
1da177e4 LT |
1456 | }; |
1457 | struct k_clock thread = { | |
2fd1f040 TG |
1458 | .clock_getres = thread_cpu_clock_getres, |
1459 | .clock_get = thread_cpu_clock_get, | |
2fd1f040 | 1460 | .timer_create = thread_cpu_timer_create, |
1da177e4 | 1461 | }; |
8356b5f9 | 1462 | struct timespec ts; |
1da177e4 | 1463 | |
52708737 TG |
1464 | posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process); |
1465 | posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread); | |
1da177e4 | 1466 | |
a42548a1 | 1467 | cputime_to_timespec(cputime_one_jiffy, &ts); |
8356b5f9 SG |
1468 | onecputick = ts.tv_nsec; |
1469 | WARN_ON(ts.tv_sec != 0); | |
1470 | ||
1da177e4 LT |
1471 | return 0; |
1472 | } | |
1473 | __initcall(init_posix_cpu_timers); |