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