kernel/time/posix-cpu-timers.c

   1 /*
   2  * Implement CPU time clocks for the POSIX clock interface.
   3  */
   4
   5 #include <linux/sched/signal.h>
   6 #include <linux/sched/cputime.h>
   7 #include <linux/posix-timers.h>
   8 #include <linux/errno.h>
   9 #include <linux/math64.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/kernel_stat.h>
  12 #include <trace/events/timer.h>
  13 #include <linux/tick.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/compat.h>
  16
  17 #include "posix-timers.h"
  18
  19 static void posix_cpu_timer_rearm(struct k_itimer *timer);
  20
  21 /*
  22  * Called after updating RLIMIT_CPU to run cpu timer and update
  23  * tsk->signal->cputime_expires expiration cache if necessary. Needs
  24  * siglock protection since other code may update expiration cache as
  25  * well.
  26  */
  27 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
  28 {
  29         u64 nsecs = rlim_new * NSEC_PER_SEC;
  30
  31         spin_lock_irq(&task->sighand->siglock);
  32         set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
  33         spin_unlock_irq(&task->sighand->siglock);
  34 }
  35
  36 static int check_clock(const clockid_t which_clock)
  37 {
  38         int error = 0;
  39         struct task_struct *p;
  40         const pid_t pid = CPUCLOCK_PID(which_clock);
  41
  42         if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
  43                 return -EINVAL;
  44
  45         if (pid == 0)
  46                 return 0;
  47
  48         rcu_read_lock();
  49         p = find_task_by_vpid(pid);
  50         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
  51                    same_thread_group(p, current) : has_group_leader_pid(p))) {
  52                 error = -EINVAL;
  53         }
  54         rcu_read_unlock();
  55
  56         return error;
  57 }
  58
  59 /*
  60  * Update expiry time from increment, and increase overrun count,
  61  * given the current clock sample.
  62  */
  63 static void bump_cpu_timer(struct k_itimer *timer, u64 now)
  64 {
  65         int i;
  66         u64 delta, incr;
  67
  68         if (timer->it.cpu.incr == 0)
  69                 return;
  70
  71         if (now < timer->it.cpu.expires)
  72                 return;
  73
  74         incr = timer->it.cpu.incr;
  75         delta = now + incr - timer->it.cpu.expires;
  76
  77         /* Don't use (incr*2 < delta), incr*2 might overflow. */
  78         for (i = 0; incr < delta - incr; i++)
  79                 incr = incr << 1;
  80
  81         for (; i >= 0; incr >>= 1, i--) {
  82                 if (delta < incr)
  83                         continue;
  84
  85                 timer->it.cpu.expires += incr;
  86                 timer->it_overrun += 1 << i;
  87                 delta -= incr;
  88         }
  89 }
  90
  91 /**
  92  * task_cputime_zero - Check a task_cputime struct for all zero fields.
  93  *
  94  * @cputime:    The struct to compare.
  95  *
  96  * Checks @cputime to see if all fields are zero.  Returns true if all fields
  97  * are zero, false if any field is nonzero.
  98  */
  99 static inline int task_cputime_zero(const struct task_cputime *cputime)
 100 {
 101         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
 102                 return 1;
 103         return 0;
 104 }
 105
 106 static inline u64 prof_ticks(struct task_struct *p)
 107 {
 108         u64 utime, stime;
 109
 110         task_cputime(p, &utime, &stime);
 111
 112         return utime + stime;
 113 }
 114 static inline u64 virt_ticks(struct task_struct *p)
 115 {
 116         u64 utime, stime;
 117
 118         task_cputime(p, &utime, &stime);
 119
 120         return utime;
 121 }
 122
 123 static int
 124 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
 125 {
 126         int error = check_clock(which_clock);
 127         if (!error) {
 128                 tp->tv_sec = 0;
 129                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
 130                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
 131                         /*
 132                          * If sched_clock is using a cycle counter, we
 133                          * don't have any idea of its true resolution
 134                          * exported, but it is much more than 1s/HZ.
 135                          */
 136                         tp->tv_nsec = 1;
 137                 }
 138         }
 139         return error;
 140 }
 141
 142 static int
 143 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec64 *tp)
 144 {
 145         /*
 146          * You can never reset a CPU clock, but we check for other errors
 147          * in the call before failing with EPERM.
 148          */
 149         int error = check_clock(which_clock);
 150         if (error == 0) {
 151                 error = -EPERM;
 152         }
 153         return error;
 154 }
 155
 156
 157 /*
 158  * Sample a per-thread clock for the given task.
 159  */
 160 static int cpu_clock_sample(const clockid_t which_clock,
 161                             struct task_struct *p, u64 *sample)
 162 {
 163         switch (CPUCLOCK_WHICH(which_clock)) {
 164         default:
 165                 return -EINVAL;
 166         case CPUCLOCK_PROF:
 167                 *sample = prof_ticks(p);
 168                 break;
 169         case CPUCLOCK_VIRT:
 170                 *sample = virt_ticks(p);
 171                 break;
 172         case CPUCLOCK_SCHED:
 173                 *sample = task_sched_runtime(p);
 174                 break;
 175         }
 176         return 0;
 177 }
 178
 179 /*
 180  * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
 181  * to avoid race conditions with concurrent updates to cputime.
 182  */
 183 static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
 184 {
 185         u64 curr_cputime;
 186 retry:
 187         curr_cputime = atomic64_read(cputime);
 188         if (sum_cputime > curr_cputime) {
 189                 if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
 190                         goto retry;
 191         }
 192 }
 193
 194 static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
 195 {
 196         __update_gt_cputime(&cputime_atomic->utime, sum->utime);
 197         __update_gt_cputime(&cputime_atomic->stime, sum->stime);
 198         __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
 199 }
 200
 201 /* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */
 202 static inline void sample_cputime_atomic(struct task_cputime *times,
 203                                          struct task_cputime_atomic *atomic_times)
 204 {
 205         times->utime = atomic64_read(&atomic_times->utime);
 206         times->stime = atomic64_read(&atomic_times->stime);
 207         times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime);
 208 }
 209
 210 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 211 {
 212         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 213         struct task_cputime sum;
 214
 215         /* Check if cputimer isn't running. This is accessed without locking. */
 216         if (!READ_ONCE(cputimer->running)) {
 217                 /*
 218                  * The POSIX timer interface allows for absolute time expiry
 219                  * values through the TIMER_ABSTIME flag, therefore we have
 220                  * to synchronize the timer to the clock every time we start it.
 221                  */
 222                 thread_group_cputime(tsk, &sum);
 223                 update_gt_cputime(&cputimer->cputime_atomic, &sum);
 224
 225                 /*
 226                  * We're setting cputimer->running without a lock. Ensure
 227                  * this only gets written to in one operation. We set
 228                  * running after update_gt_cputime() as a small optimization,
 229                  * but barriers are not required because update_gt_cputime()
 230                  * can handle concurrent updates.
 231                  */
 232                 WRITE_ONCE(cputimer->running, true);
 233         }
 234         sample_cputime_atomic(times, &cputimer->cputime_atomic);
 235 }
 236
 237 /*
 238  * Sample a process (thread group) clock for the given group_leader task.
 239  * Must be called with task sighand lock held for safe while_each_thread()
 240  * traversal.
 241  */
 242 static int cpu_clock_sample_group(const clockid_t which_clock,
 243                                   struct task_struct *p,
 244                                   u64 *sample)
 245 {
 246         struct task_cputime cputime;
 247
 248         switch (CPUCLOCK_WHICH(which_clock)) {
 249         default:
 250                 return -EINVAL;
 251         case CPUCLOCK_PROF:
 252                 thread_group_cputime(p, &cputime);
 253                 *sample = cputime.utime + cputime.stime;
 254                 break;
 255         case CPUCLOCK_VIRT:
 256                 thread_group_cputime(p, &cputime);
 257                 *sample = cputime.utime;
 258                 break;
 259         case CPUCLOCK_SCHED:
 260                 thread_group_cputime(p, &cputime);
 261                 *sample = cputime.sum_exec_runtime;
 262                 break;
 263         }
 264         return 0;
 265 }
 266
 267 static int posix_cpu_clock_get_task(struct task_struct *tsk,
 268                                     const clockid_t which_clock,
 269                                     struct timespec64 *tp)
 270 {
 271         int err = -EINVAL;
 272         u64 rtn;
 273
 274         if (CPUCLOCK_PERTHREAD(which_clock)) {
 275                 if (same_thread_group(tsk, current))
 276                         err = cpu_clock_sample(which_clock, tsk, &rtn);
 277         } else {
 278                 if (tsk == current || thread_group_leader(tsk))
 279                         err = cpu_clock_sample_group(which_clock, tsk, &rtn);
 280         }
 281
 282         if (!err)
 283                 *tp = ns_to_timespec64(rtn);
 284
 285         return err;
 286 }
 287
 288
 289 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec64 *tp)
 290 {
 291         const pid_t pid = CPUCLOCK_PID(which_clock);
 292         int err = -EINVAL;
 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                  */
 299                 err = posix_cpu_clock_get_task(current, which_clock, tp);
 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;
 306                 rcu_read_lock();
 307                 p = find_task_by_vpid(pid);
 308                 if (p)
 309                         err = posix_cpu_clock_get_task(p, which_clock, tp);
 310                 rcu_read_unlock();
 311         }
 312
 313         return err;
 314 }
 315
 316 /*
 317  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
 318  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
 319  * new timer already all-zeros initialized.
 320  */
 321 static int posix_cpu_timer_create(struct k_itimer *new_timer)
 322 {
 323         int ret = 0;
 324         const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
 325         struct task_struct *p;
 326
 327         if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
 328                 return -EINVAL;
 329
 330         new_timer->kclock = &clock_posix_cpu;
 331
 332         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
 333
 334         rcu_read_lock();
 335         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
 336                 if (pid == 0) {
 337                         p = current;
 338                 } else {
 339                         p = find_task_by_vpid(pid);
 340                         if (p && !same_thread_group(p, current))
 341                                 p = NULL;
 342                 }
 343         } else {
 344                 if (pid == 0) {
 345                         p = current->group_leader;
 346                 } else {
 347                         p = find_task_by_vpid(pid);
 348                         if (p && !has_group_leader_pid(p))
 349                                 p = NULL;
 350                 }
 351         }
 352         new_timer->it.cpu.task = p;
 353         if (p) {
 354                 get_task_struct(p);
 355         } else {
 356                 ret = -EINVAL;
 357         }
 358         rcu_read_unlock();
 359
 360         return ret;
 361 }
 362
 363 /*
 364  * Clean up a CPU-clock timer that is about to be destroyed.
 365  * This is called from timer deletion with the timer already locked.
 366  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 367  * and try again.  (This happens when the timer is in the middle of firing.)
 368  */
 369 static int posix_cpu_timer_del(struct k_itimer *timer)
 370 {
 371         int ret = 0;
 372         unsigned long flags;
 373         struct sighand_struct *sighand;
 374         struct task_struct *p = timer->it.cpu.task;
 375
 376         WARN_ON_ONCE(p == NULL);
 377
 378         /*
 379          * Protect against sighand release/switch in exit/exec and process/
 380          * thread timer list entry concurrent read/writes.
 381          */
 382         sighand = lock_task_sighand(p, &flags);
 383         if (unlikely(sighand == NULL)) {
 384                 /*
 385                  * We raced with the reaping of the task.
 386                  * The deletion should have cleared us off the list.
 387                  */
 388                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
 389         } else {
 390                 if (timer->it.cpu.firing)
 391                         ret = TIMER_RETRY;
 392                 else
 393                         list_del(&timer->it.cpu.entry);
 394
 395                 unlock_task_sighand(p, &flags);
 396         }
 397
 398         if (!ret)
 399                 put_task_struct(p);
 400
 401         return ret;
 402 }
 403
 404 static void cleanup_timers_list(struct list_head *head)
 405 {
 406         struct cpu_timer_list *timer, *next;
 407
 408         list_for_each_entry_safe(timer, next, head, entry)
 409                 list_del_init(&timer->entry);
 410 }
 411
 412 /*
 413  * Clean out CPU timers still ticking when a thread exited.  The task
 414  * pointer is cleared, and the expiry time is replaced with the residual
 415  * time for later timer_gettime calls to return.
 416  * This must be called with the siglock held.
 417  */
 418 static void cleanup_timers(struct list_head *head)
 419 {
 420         cleanup_timers_list(head);
 421         cleanup_timers_list(++head);
 422         cleanup_timers_list(++head);
 423 }
 424
 425 /*
 426  * These are both called with the siglock held, when the current thread
 427  * is being reaped.  When the final (leader) thread in the group is reaped,
 428  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
 429  */
 430 void posix_cpu_timers_exit(struct task_struct *tsk)
 431 {
 432         cleanup_timers(tsk->cpu_timers);
 433 }
 434 void posix_cpu_timers_exit_group(struct task_struct *tsk)
 435 {
 436         cleanup_timers(tsk->signal->cpu_timers);
 437 }
 438
 439 static inline int expires_gt(u64 expires, u64 new_exp)
 440 {
 441         return expires == 0 || expires > new_exp;
 442 }
 443
 444 /*
 445  * Insert the timer on the appropriate list before any timers that
 446  * expire later.  This must be called with the sighand lock held.
 447  */
 448 static void arm_timer(struct k_itimer *timer)
 449 {
 450         struct task_struct *p = timer->it.cpu.task;
 451         struct list_head *head, *listpos;
 452         struct task_cputime *cputime_expires;
 453         struct cpu_timer_list *const nt = &timer->it.cpu;
 454         struct cpu_timer_list *next;
 455
 456         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 457                 head = p->cpu_timers;
 458                 cputime_expires = &p->cputime_expires;
 459         } else {
 460                 head = p->signal->cpu_timers;
 461                 cputime_expires = &p->signal->cputime_expires;
 462         }
 463         head += CPUCLOCK_WHICH(timer->it_clock);
 464
 465         listpos = head;
 466         list_for_each_entry(next, head, entry) {
 467                 if (nt->expires < next->expires)
 468                         break;
 469                 listpos = &next->entry;
 470         }
 471         list_add(&nt->entry, listpos);
 472
 473         if (listpos == head) {
 474                 u64 exp = nt->expires;
 475
 476                 /*
 477                  * We are the new earliest-expiring POSIX 1.b timer, hence
 478                  * need to update expiration cache. Take into account that
 479                  * for process timers we share expiration cache with itimers
 480                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
 481                  */
 482
 483                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
 484                 case CPUCLOCK_PROF:
 485                         if (expires_gt(cputime_expires->prof_exp, exp))
 486                                 cputime_expires->prof_exp = exp;
 487                         break;
 488                 case CPUCLOCK_VIRT:
 489                         if (expires_gt(cputime_expires->virt_exp, exp))
 490                                 cputime_expires->virt_exp = exp;
 491                         break;
 492                 case CPUCLOCK_SCHED:
 493                         if (expires_gt(cputime_expires->sched_exp, exp))
 494                                 cputime_expires->sched_exp = exp;
 495                         break;
 496                 }
 497                 if (CPUCLOCK_PERTHREAD(timer->it_clock))
 498                         tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
 499                 else
 500                         tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
 501         }
 502 }
 503
 504 /*
 505  * The timer is locked, fire it and arrange for its reload.
 506  */
 507 static void cpu_timer_fire(struct k_itimer *timer)
 508 {
 509         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
 510                 /*
 511                  * User don't want any signal.
 512                  */
 513                 timer->it.cpu.expires = 0;
 514         } else if (unlikely(timer->sigq == NULL)) {
 515                 /*
 516                  * This a special case for clock_nanosleep,
 517                  * not a normal timer from sys_timer_create.
 518                  */
 519                 wake_up_process(timer->it_process);
 520                 timer->it.cpu.expires = 0;
 521         } else if (timer->it.cpu.incr == 0) {
 522                 /*
 523                  * One-shot timer.  Clear it as soon as it's fired.
 524                  */
 525                 posix_timer_event(timer, 0);
 526                 timer->it.cpu.expires = 0;
 527         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
 528                 /*
 529                  * The signal did not get queued because the signal
 530                  * was ignored, so we won't get any callback to
 531                  * reload the timer.  But we need to keep it
 532                  * ticking in case the signal is deliverable next time.
 533                  */
 534                 posix_cpu_timer_rearm(timer);
 535                 ++timer->it_requeue_pending;
 536         }
 537 }
 538
 539 /*
 540  * Sample a process (thread group) timer for the given group_leader task.
 541  * Must be called with task sighand lock held for safe while_each_thread()
 542  * traversal.
 543  */
 544 static int cpu_timer_sample_group(const clockid_t which_clock,
 545                                   struct task_struct *p, u64 *sample)
 546 {
 547         struct task_cputime cputime;
 548
 549         thread_group_cputimer(p, &cputime);
 550         switch (CPUCLOCK_WHICH(which_clock)) {
 551         default:
 552                 return -EINVAL;
 553         case CPUCLOCK_PROF:
 554                 *sample = cputime.utime + cputime.stime;
 555                 break;
 556         case CPUCLOCK_VIRT:
 557                 *sample = cputime.utime;
 558                 break;
 559         case CPUCLOCK_SCHED:
 560                 *sample = cputime.sum_exec_runtime;
 561                 break;
 562         }
 563         return 0;
 564 }
 565
 566 /*
 567  * Guts of sys_timer_settime for CPU timers.
 568  * This is called with the timer locked and interrupts disabled.
 569  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 570  * and try again.  (This happens when the timer is in the middle of firing.)
 571  */
 572 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 573                                struct itimerspec64 *new, struct itimerspec64 *old)
 574 {
 575         unsigned long flags;
 576         struct sighand_struct *sighand;
 577         struct task_struct *p = timer->it.cpu.task;
 578         u64 old_expires, new_expires, old_incr, val;
 579         int ret;
 580
 581         WARN_ON_ONCE(p == NULL);
 582
 583         /*
 584          * Use the to_ktime conversion because that clamps the maximum
 585          * value to KTIME_MAX and avoid multiplication overflows.
 586          */
 587         new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
 588
 589         /*
 590          * Protect against sighand release/switch in exit/exec and p->cpu_timers
 591          * and p->signal->cpu_timers read/write in arm_timer()
 592          */
 593         sighand = lock_task_sighand(p, &flags);
 594         /*
 595          * If p has just been reaped, we can no
 596          * longer get any information about it at all.
 597          */
 598         if (unlikely(sighand == NULL)) {
 599                 return -ESRCH;
 600         }
 601
 602         /*
 603          * Disarm any old timer after extracting its expiry time.
 604          */
 605         WARN_ON_ONCE(!irqs_disabled());
 606
 607         ret = 0;
 608         old_incr = timer->it.cpu.incr;
 609         old_expires = timer->it.cpu.expires;
 610         if (unlikely(timer->it.cpu.firing)) {
 611                 timer->it.cpu.firing = -1;
 612                 ret = TIMER_RETRY;
 613         } else
 614                 list_del_init(&timer->it.cpu.entry);
 615
 616         /*
 617          * We need to sample the current value to convert the new
 618          * value from to relative and absolute, and to convert the
 619          * old value from absolute to relative.  To set a process
 620          * timer, we need a sample to balance the thread expiry
 621          * times (in arm_timer).  With an absolute time, we must
 622          * check if it's already passed.  In short, we need a sample.
 623          */
 624         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 625                 cpu_clock_sample(timer->it_clock, p, &val);
 626         } else {
 627                 cpu_timer_sample_group(timer->it_clock, p, &val);
 628         }
 629
 630         if (old) {
 631                 if (old_expires == 0) {
 632                         old->it_value.tv_sec = 0;
 633                         old->it_value.tv_nsec = 0;
 634                 } else {
 635                         /*
 636                          * Update the timer in case it has
 637                          * overrun already.  If it has,
 638                          * we'll report it as having overrun
 639                          * and with the next reloaded timer
 640                          * already ticking, though we are
 641                          * swallowing that pending
 642                          * notification here to install the
 643                          * new setting.
 644                          */
 645                         bump_cpu_timer(timer, val);
 646                         if (val < timer->it.cpu.expires) {
 647                                 old_expires = timer->it.cpu.expires - val;
 648                                 old->it_value = ns_to_timespec64(old_expires);
 649                         } else {
 650                                 old->it_value.tv_nsec = 1;
 651                                 old->it_value.tv_sec = 0;
 652                         }
 653                 }
 654         }
 655
 656         if (unlikely(ret)) {
 657                 /*
 658                  * We are colliding with the timer actually firing.
 659                  * Punt after filling in the timer's old value, and
 660                  * disable this firing since we are already reporting
 661                  * it as an overrun (thanks to bump_cpu_timer above).
 662                  */
 663                 unlock_task_sighand(p, &flags);
 664                 goto out;
 665         }
 666
 667         if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
 668                 new_expires += val;
 669         }
 670
 671         /*
 672          * Install the new expiry time (or zero).
 673          * For a timer with no notification action, we don't actually
 674          * arm the timer (we'll just fake it for timer_gettime).
 675          */
 676         timer->it.cpu.expires = new_expires;
 677         if (new_expires != 0 && val < new_expires) {
 678                 arm_timer(timer);
 679         }
 680
 681         unlock_task_sighand(p, &flags);
 682         /*
 683          * Install the new reload setting, and
 684          * set up the signal and overrun bookkeeping.
 685          */
 686         timer->it.cpu.incr = timespec64_to_ns(&new->it_interval);
 687
 688         /*
 689          * This acts as a modification timestamp for the timer,
 690          * so any automatic reload attempt will punt on seeing
 691          * that we have reset the timer manually.
 692          */
 693         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
 694                 ~REQUEUE_PENDING;
 695         timer->it_overrun_last = 0;
 696         timer->it_overrun = -1;
 697
 698         if (new_expires != 0 && !(val < new_expires)) {
 699                 /*
 700                  * The designated time already passed, so we notify
 701                  * immediately, even if the thread never runs to
 702                  * accumulate more time on this clock.
 703                  */
 704                 cpu_timer_fire(timer);
 705         }
 706
 707         ret = 0;
 708  out:
 709         if (old)
 710                 old->it_interval = ns_to_timespec64(old_incr);
 711
 712         return ret;
 713 }
 714
 715 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
 716 {
 717         u64 now;
 718         struct task_struct *p = timer->it.cpu.task;
 719
 720         WARN_ON_ONCE(p == NULL);
 721
 722         /*
 723          * Easy part: convert the reload time.
 724          */
 725         itp->it_interval = ns_to_timespec64(timer->it.cpu.incr);
 726
 727         if (!timer->it.cpu.expires)
 728                 return;
 729
 730         /*
 731          * Sample the clock to take the difference with the expiry time.
 732          */
 733         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 734                 cpu_clock_sample(timer->it_clock, p, &now);
 735         } else {
 736                 struct sighand_struct *sighand;
 737                 unsigned long flags;
 738
 739                 /*
 740                  * Protect against sighand release/switch in exit/exec and
 741                  * also make timer sampling safe if it ends up calling
 742                  * thread_group_cputime().
 743                  */
 744                 sighand = lock_task_sighand(p, &flags);
 745                 if (unlikely(sighand == NULL)) {
 746                         /*
 747                          * The process has been reaped.
 748                          * We can't even collect a sample any more.
 749                          * Call the timer disarmed, nothing else to do.
 750                          */
 751                         timer->it.cpu.expires = 0;
 752                         return;
 753                 } else {
 754                         cpu_timer_sample_group(timer->it_clock, p, &now);
 755                         unlock_task_sighand(p, &flags);
 756                 }
 757         }
 758
 759         if (now < timer->it.cpu.expires) {
 760                 itp->it_value = ns_to_timespec64(timer->it.cpu.expires - now);
 761         } else {
 762                 /*
 763                  * The timer should have expired already, but the firing
 764                  * hasn't taken place yet.  Say it's just about to expire.
 765                  */
 766                 itp->it_value.tv_nsec = 1;
 767                 itp->it_value.tv_sec = 0;
 768         }
 769 }
 770
 771 static unsigned long long
 772 check_timers_list(struct list_head *timers,
 773                   struct list_head *firing,
 774                   unsigned long long curr)
 775 {
 776         int maxfire = 20;
 777
 778         while (!list_empty(timers)) {
 779                 struct cpu_timer_list *t;
 780
 781                 t = list_first_entry(timers, struct cpu_timer_list, entry);
 782
 783                 if (!--maxfire || curr < t->expires)
 784                         return t->expires;
 785
 786                 t->firing = 1;
 787                 list_move_tail(&t->entry, firing);
 788         }
 789
 790         return 0;
 791 }
 792
 793 /*
 794  * Check for any per-thread CPU timers that have fired and move them off
 795  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
 796  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
 797  */
 798 static void check_thread_timers(struct task_struct *tsk,
 799                                 struct list_head *firing)
 800 {
 801         struct list_head *timers = tsk->cpu_timers;
 802         struct task_cputime *tsk_expires = &tsk->cputime_expires;
 803         u64 expires;
 804         unsigned long soft;
 805
 806         /*
 807          * If cputime_expires is zero, then there are no active
 808          * per thread CPU timers.
 809          */
 810         if (task_cputime_zero(&tsk->cputime_expires))
 811                 return;
 812
 813         expires = check_timers_list(timers, firing, prof_ticks(tsk));
 814         tsk_expires->prof_exp = expires;
 815
 816         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
 817         tsk_expires->virt_exp = expires;
 818
 819         tsk_expires->sched_exp = check_timers_list(++timers, firing,
 820                                                    tsk->se.sum_exec_runtime);
 821
 822         /*
 823          * Check for the special case thread timers.
 824          */
 825         soft = task_rlimit(tsk, RLIMIT_RTTIME);
 826         if (soft != RLIM_INFINITY) {
 827                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
 828
 829                 if (hard != RLIM_INFINITY &&
 830                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
 831                         /*
 832                          * At the hard limit, we just die.
 833                          * No need to calculate anything else now.
 834                          */
 835                         if (print_fatal_signals) {
 836                                 pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
 837                                         tsk->comm, task_pid_nr(tsk));
 838                         }
 839                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 840                         return;
 841                 }
 842                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
 843                         /*
 844                          * At the soft limit, send a SIGXCPU every second.
 845                          */
 846                         if (soft < hard) {
 847                                 soft += USEC_PER_SEC;
 848                                 tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur =
 849                                         soft;
 850                         }
 851                         if (print_fatal_signals) {
 852                                 pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
 853                                         tsk->comm, task_pid_nr(tsk));
 854                         }
 855                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 856                 }
 857         }
 858         if (task_cputime_zero(tsk_expires))
 859                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 860 }
 861
 862 static inline void stop_process_timers(struct signal_struct *sig)
 863 {
 864         struct thread_group_cputimer *cputimer = &sig->cputimer;
 865
 866         /* Turn off cputimer->running. This is done without locking. */
 867         WRITE_ONCE(cputimer->running, false);
 868         tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
 869 }
 870
 871 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 872                              u64 *expires, u64 cur_time, int signo)
 873 {
 874         if (!it->expires)
 875                 return;
 876
 877         if (cur_time >= it->expires) {
 878                 if (it->incr)
 879                         it->expires += it->incr;
 880                 else
 881                         it->expires = 0;
 882
 883                 trace_itimer_expire(signo == SIGPROF ?
 884                                     ITIMER_PROF : ITIMER_VIRTUAL,
 885                                     tsk->signal->leader_pid, cur_time);
 886                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
 887         }
 888
 889         if (it->expires && (!*expires || it->expires < *expires))
 890                 *expires = it->expires;
 891 }
 892
 893 /*
 894  * Check for any per-thread CPU timers that have fired and move them
 895  * off the tsk->*_timers list onto the firing list.  Per-thread timers
 896  * have already been taken off.
 897  */
 898 static void check_process_timers(struct task_struct *tsk,
 899                                  struct list_head *firing)
 900 {
 901         struct signal_struct *const sig = tsk->signal;
 902         u64 utime, ptime, virt_expires, prof_expires;
 903         u64 sum_sched_runtime, sched_expires;
 904         struct list_head *timers = sig->cpu_timers;
 905         struct task_cputime cputime;
 906         unsigned long soft;
 907
 908         /*
 909          * If cputimer is not running, then there are no active
 910          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
 911          */
 912         if (!READ_ONCE(tsk->signal->cputimer.running))
 913                 return;
 914
 915         /*
 916          * Signify that a thread is checking for process timers.
 917          * Write access to this field is protected by the sighand lock.
 918          */
 919         sig->cputimer.checking_timer = true;
 920
 921         /*
 922          * Collect the current process totals.
 923          */
 924         thread_group_cputimer(tsk, &cputime);
 925         utime = cputime.utime;
 926         ptime = utime + cputime.stime;
 927         sum_sched_runtime = cputime.sum_exec_runtime;
 928
 929         prof_expires = check_timers_list(timers, firing, ptime);
 930         virt_expires = check_timers_list(++timers, firing, utime);
 931         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
 932
 933         /*
 934          * Check for the special case process timers.
 935          */
 936         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
 937                          SIGPROF);
 938         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
 939                          SIGVTALRM);
 940         soft = task_rlimit(tsk, RLIMIT_CPU);
 941         if (soft != RLIM_INFINITY) {
 942                 unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
 943                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
 944                 u64 x;
 945                 if (psecs >= hard) {
 946                         /*
 947                          * At the hard limit, we just die.
 948                          * No need to calculate anything else now.
 949                          */
 950                         if (print_fatal_signals) {
 951                                 pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
 952                                         tsk->comm, task_pid_nr(tsk));
 953                         }
 954                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 955                         return;
 956                 }
 957                 if (psecs >= soft) {
 958                         /*
 959                          * At the soft limit, send a SIGXCPU every second.
 960                          */
 961                         if (print_fatal_signals) {
 962                                 pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
 963                                         tsk->comm, task_pid_nr(tsk));
 964                         }
 965                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 966                         if (soft < hard) {
 967                                 soft++;
 968                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
 969                         }
 970                 }
 971                 x = soft * NSEC_PER_SEC;
 972                 if (!prof_expires || x < prof_expires)
 973                         prof_expires = x;
 974         }
 975
 976         sig->cputime_expires.prof_exp = prof_expires;
 977         sig->cputime_expires.virt_exp = virt_expires;
 978         sig->cputime_expires.sched_exp = sched_expires;
 979         if (task_cputime_zero(&sig->cputime_expires))
 980                 stop_process_timers(sig);
 981
 982         sig->cputimer.checking_timer = false;
 983 }
 984
 985 /*
 986  * This is called from the signal code (via posixtimer_rearm)
 987  * when the last timer signal was delivered and we have to reload the timer.
 988  */
 989 static void posix_cpu_timer_rearm(struct k_itimer *timer)
 990 {
 991         struct sighand_struct *sighand;
 992         unsigned long flags;
 993         struct task_struct *p = timer->it.cpu.task;
 994         u64 now;
 995
 996         WARN_ON_ONCE(p == NULL);
 997
 998         /*
 999          * Fetch the current sample and update the timer's expiry time.
1000          */
1001         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1002                 cpu_clock_sample(timer->it_clock, p, &now);
1003                 bump_cpu_timer(timer, now);
1004                 if (unlikely(p->exit_state))
1005                         return;
1006
1007                 /* Protect timer list r/w in arm_timer() */
1008                 sighand = lock_task_sighand(p, &flags);
1009                 if (!sighand)
1010                         return;
1011         } else {
1012                 /*
1013                  * Protect arm_timer() and timer sampling in case of call to
1014                  * thread_group_cputime().
1015                  */
1016                 sighand = lock_task_sighand(p, &flags);
1017                 if (unlikely(sighand == NULL)) {
1018                         /*
1019                          * The process has been reaped.
1020                          * We can't even collect a sample any more.
1021                          */
1022                         timer->it.cpu.expires = 0;
1023                         return;
1024                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1025                         /* If the process is dying, no need to rearm */
1026                         goto unlock;
1027                 }
1028                 cpu_timer_sample_group(timer->it_clock, p, &now);
1029                 bump_cpu_timer(timer, now);
1030                 /* Leave the sighand locked for the call below.  */
1031         }
1032
1033         /*
1034          * Now re-arm for the new expiry time.
1035          */
1036         WARN_ON_ONCE(!irqs_disabled());
1037         arm_timer(timer);
1038 unlock:
1039         unlock_task_sighand(p, &flags);
1040 }
1041
1042 /**
1043  * task_cputime_expired - Compare two task_cputime entities.
1044  *
1045  * @sample:     The task_cputime structure to be checked for expiration.
1046  * @expires:    Expiration times, against which @sample will be checked.
1047  *
1048  * Checks @sample against @expires to see if any field of @sample has expired.
1049  * Returns true if any field of the former is greater than the corresponding
1050  * field of the latter if the latter field is set.  Otherwise returns false.
1051  */
1052 static inline int task_cputime_expired(const struct task_cputime *sample,
1053                                         const struct task_cputime *expires)
1054 {
1055         if (expires->utime && sample->utime >= expires->utime)
1056                 return 1;
1057         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1058                 return 1;
1059         if (expires->sum_exec_runtime != 0 &&
1060             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1061                 return 1;
1062         return 0;
1063 }
1064
1065 /**
1066  * fastpath_timer_check - POSIX CPU timers fast path.
1067  *
1068  * @tsk:        The task (thread) being checked.
1069  *
1070  * Check the task and thread group timers.  If both are zero (there are no
1071  * timers set) return false.  Otherwise snapshot the task and thread group
1072  * timers and compare them with the corresponding expiration times.  Return
1073  * true if a timer has expired, else return false.
1074  */
1075 static inline int fastpath_timer_check(struct task_struct *tsk)
1076 {
1077         struct signal_struct *sig;
1078
1079         if (!task_cputime_zero(&tsk->cputime_expires)) {
1080                 struct task_cputime task_sample;
1081
1082                 task_cputime(tsk, &task_sample.utime, &task_sample.stime);
1083                 task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
1084                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1085                         return 1;
1086         }
1087
1088         sig = tsk->signal;
1089         /*
1090          * Check if thread group timers expired when the cputimer is
1091          * running and no other thread in the group is already checking
1092          * for thread group cputimers. These fields are read without the
1093          * sighand lock. However, this is fine because this is meant to
1094          * be a fastpath heuristic to determine whether we should try to
1095          * acquire the sighand lock to check/handle timers.
1096          *
1097          * In the worst case scenario, if 'running' or 'checking_timer' gets
1098          * set but the current thread doesn't see the change yet, we'll wait
1099          * until the next thread in the group gets a scheduler interrupt to
1100          * handle the timer. This isn't an issue in practice because these
1101          * types of delays with signals actually getting sent are expected.
1102          */
1103         if (READ_ONCE(sig->cputimer.running) &&
1104             !READ_ONCE(sig->cputimer.checking_timer)) {
1105                 struct task_cputime group_sample;
1106
1107                 sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
1108
1109                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1110                         return 1;
1111         }
1112
1113         return 0;
1114 }
1115
1116 /*
1117  * This is called from the timer interrupt handler.  The irq handler has
1118  * already updated our counts.  We need to check if any timers fire now.
1119  * Interrupts are disabled.
1120  */
1121 void run_posix_cpu_timers(struct task_struct *tsk)
1122 {
1123         LIST_HEAD(firing);
1124         struct k_itimer *timer, *next;
1125         unsigned long flags;
1126
1127         WARN_ON_ONCE(!irqs_disabled());
1128
1129         /*
1130          * The fast path checks that there are no expired thread or thread
1131          * group timers.  If that's so, just return.
1132          */
1133         if (!fastpath_timer_check(tsk))
1134                 return;
1135
1136         if (!lock_task_sighand(tsk, &flags))
1137                 return;
1138         /*
1139          * Here we take off tsk->signal->cpu_timers[N] and
1140          * tsk->cpu_timers[N] all the timers that are firing, and
1141          * put them on the firing list.
1142          */
1143         check_thread_timers(tsk, &firing);
1144
1145         check_process_timers(tsk, &firing);
1146
1147         /*
1148          * We must release these locks before taking any timer's lock.
1149          * There is a potential race with timer deletion here, as the
1150          * siglock now protects our private firing list.  We have set
1151          * the firing flag in each timer, so that a deletion attempt
1152          * that gets the timer lock before we do will give it up and
1153          * spin until we've taken care of that timer below.
1154          */
1155         unlock_task_sighand(tsk, &flags);
1156
1157         /*
1158          * Now that all the timers on our list have the firing flag,
1159          * no one will touch their list entries but us.  We'll take
1160          * each timer's lock before clearing its firing flag, so no
1161          * timer call will interfere.
1162          */
1163         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1164                 int cpu_firing;
1165
1166                 spin_lock(&timer->it_lock);
1167                 list_del_init(&timer->it.cpu.entry);
1168                 cpu_firing = timer->it.cpu.firing;
1169                 timer->it.cpu.firing = 0;
1170                 /*
1171                  * The firing flag is -1 if we collided with a reset
1172                  * of the timer, which already reported this
1173                  * almost-firing as an overrun.  So don't generate an event.
1174                  */
1175                 if (likely(cpu_firing >= 0))
1176                         cpu_timer_fire(timer);
1177                 spin_unlock(&timer->it_lock);
1178         }
1179 }
1180
1181 /*
1182  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1183  * The tsk->sighand->siglock must be held by the caller.
1184  */
1185 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1186                            u64 *newval, u64 *oldval)
1187 {
1188         u64 now;
1189
1190         WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
1191         cpu_timer_sample_group(clock_idx, tsk, &now);
1192
1193         if (oldval) {
1194                 /*
1195                  * We are setting itimer. The *oldval is absolute and we update
1196                  * it to be relative, *newval argument is relative and we update
1197                  * it to be absolute.
1198                  */
1199                 if (*oldval) {
1200                         if (*oldval <= now) {
1201                                 /* Just about to fire. */
1202                                 *oldval = TICK_NSEC;
1203                         } else {
1204                                 *oldval -= now;
1205                         }
1206                 }
1207
1208                 if (!*newval)
1209                         return;
1210                 *newval += now;
1211         }
1212
1213         /*
1214          * Update expiration cache if we are the earliest timer, or eventually
1215          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1216          */
1217         switch (clock_idx) {
1218         case CPUCLOCK_PROF:
1219                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1220                         tsk->signal->cputime_expires.prof_exp = *newval;
1221                 break;
1222         case CPUCLOCK_VIRT:
1223                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1224                         tsk->signal->cputime_expires.virt_exp = *newval;
1225                 break;
1226         }
1227
1228         tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1229 }
1230
1231 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1232                             const struct timespec64 *rqtp)
1233 {
1234         struct itimerspec64 it;
1235         struct k_itimer timer;
1236         u64 expires;
1237         int error;
1238
1239         /*
1240          * Set up a temporary timer and then wait for it to go off.
1241          */
1242         memset(&timer, 0, sizeof timer);
1243         spin_lock_init(&timer.it_lock);
1244         timer.it_clock = which_clock;
1245         timer.it_overrun = -1;
1246         error = posix_cpu_timer_create(&timer);
1247         timer.it_process = current;
1248         if (!error) {
1249                 static struct itimerspec64 zero_it;
1250                 struct restart_block *restart;
1251
1252                 memset(&it, 0, sizeof(it));
1253                 it.it_value = *rqtp;
1254
1255                 spin_lock_irq(&timer.it_lock);
1256                 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1257                 if (error) {
1258                         spin_unlock_irq(&timer.it_lock);
1259                         return error;
1260                 }
1261
1262                 while (!signal_pending(current)) {
1263                         if (timer.it.cpu.expires == 0) {
1264                                 /*
1265                                  * Our timer fired and was reset, below
1266                                  * deletion can not fail.
1267                                  */
1268                                 posix_cpu_timer_del(&timer);
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                 expires = timer.it.cpu.expires;
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                 }
1293                 spin_unlock_irq(&timer.it_lock);
1294
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
1306                 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1307                         /*
1308                          * It actually did fire already.
1309                          */
1310                         return 0;
1311                 }
1312
1313                 error = -ERESTART_RESTARTBLOCK;
1314                 /*
1315                  * Report back to the user the time still remaining.
1316                  */
1317                 restart = &current->restart_block;
1318                 restart->nanosleep.expires = expires;
1319                 if (restart->nanosleep.type != TT_NONE)
1320                         error = nanosleep_copyout(restart, &it.it_value);
1321         }
1322
1323         return error;
1324 }
1325
1326 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1327
1328 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1329                             const struct timespec64 *rqtp)
1330 {
1331         struct restart_block *restart_block = &current->restart_block;
1332         int error;
1333
1334         /*
1335          * Diagnose required errors first.
1336          */
1337         if (CPUCLOCK_PERTHREAD(which_clock) &&
1338             (CPUCLOCK_PID(which_clock) == 0 ||
1339              CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1340                 return -EINVAL;
1341
1342         error = do_cpu_nanosleep(which_clock, flags, rqtp);
1343
1344         if (error == -ERESTART_RESTARTBLOCK) {
1345
1346                 if (flags & TIMER_ABSTIME)
1347                         return -ERESTARTNOHAND;
1348
1349                 restart_block->fn = posix_cpu_nsleep_restart;
1350                 restart_block->nanosleep.clockid = which_clock;
1351         }
1352         return error;
1353 }
1354
1355 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1356 {
1357         clockid_t which_clock = restart_block->nanosleep.clockid;
1358         struct timespec64 t;
1359
1360         t = ns_to_timespec64(restart_block->nanosleep.expires);
1361
1362         return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1363 }
1364
1365 #define PROCESS_CLOCK   MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1366 #define THREAD_CLOCK    MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1367
1368 static int process_cpu_clock_getres(const clockid_t which_clock,
1369                                     struct timespec64 *tp)
1370 {
1371         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1372 }
1373 static int process_cpu_clock_get(const clockid_t which_clock,
1374                                  struct timespec64 *tp)
1375 {
1376         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1377 }
1378 static int process_cpu_timer_create(struct k_itimer *timer)
1379 {
1380         timer->it_clock = PROCESS_CLOCK;
1381         return posix_cpu_timer_create(timer);
1382 }
1383 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1384                               const struct timespec64 *rqtp)
1385 {
1386         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1387 }
1388 static int thread_cpu_clock_getres(const clockid_t which_clock,
1389                                    struct timespec64 *tp)
1390 {
1391         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1392 }
1393 static int thread_cpu_clock_get(const clockid_t which_clock,
1394                                 struct timespec64 *tp)
1395 {
1396         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1397 }
1398 static int thread_cpu_timer_create(struct k_itimer *timer)
1399 {
1400         timer->it_clock = THREAD_CLOCK;
1401         return posix_cpu_timer_create(timer);
1402 }
1403
1404 const struct k_clock clock_posix_cpu = {
1405         .clock_getres   = posix_cpu_clock_getres,
1406         .clock_set      = posix_cpu_clock_set,
1407         .clock_get      = posix_cpu_clock_get,
1408         .timer_create   = posix_cpu_timer_create,
1409         .nsleep         = posix_cpu_nsleep,
1410         .timer_set      = posix_cpu_timer_set,
1411         .timer_del      = posix_cpu_timer_del,
1412         .timer_get      = posix_cpu_timer_get,
1413         .timer_rearm    = posix_cpu_timer_rearm,
1414 };
1415
1416 const struct k_clock clock_process = {
1417         .clock_getres   = process_cpu_clock_getres,
1418         .clock_get      = process_cpu_clock_get,
1419         .timer_create   = process_cpu_timer_create,
1420         .nsleep         = process_cpu_nsleep,
1421 };
1422
1423 const struct k_clock clock_thread = {
1424         .clock_getres   = thread_cpu_clock_getres,
1425         .clock_get      = thread_cpu_clock_get,
1426         .timer_create   = thread_cpu_timer_create,
1427 };