kernel/time/posix-cpu-timers.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Implement CPU time clocks for the POSIX clock interface.
   4  */
   5
   6 #include <linux/sched/signal.h>
   7 #include <linux/sched/cputime.h>
   8 #include <linux/posix-timers.h>
   9 #include <linux/errno.h>
  10 #include <linux/math64.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/kernel_stat.h>
  13 #include <trace/events/timer.h>
  14 #include <linux/tick.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/compat.h>
  17
  18 #include "posix-timers.h"
  19
  20 static void posix_cpu_timer_rearm(struct k_itimer *timer);
  21
  22 /*
  23  * Called after updating RLIMIT_CPU to run cpu timer and update
  24  * tsk->signal->cputime_expires expiration cache if necessary. Needs
  25  * siglock protection since other code may update expiration cache as
  26  * well.
  27  */
  28 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
  29 {
  30         u64 nsecs = rlim_new * NSEC_PER_SEC;
  31
  32         spin_lock_irq(&task->sighand->siglock);
  33         set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
  34         spin_unlock_irq(&task->sighand->siglock);
  35 }
  36
  37 static int check_clock(const clockid_t which_clock)
  38 {
  39         int error = 0;
  40         struct task_struct *p;
  41         const pid_t pid = CPUCLOCK_PID(which_clock);
  42
  43         if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
  44                 return -EINVAL;
  45
  46         if (pid == 0)
  47                 return 0;
  48
  49         rcu_read_lock();
  50         p = find_task_by_vpid(pid);
  51         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
  52                    same_thread_group(p, current) : has_group_leader_pid(p))) {
  53                 error = -EINVAL;
  54         }
  55         rcu_read_unlock();
  56
  57         return error;
  58 }
  59
  60 /*
  61  * Update expiry time from increment, and increase overrun count,
  62  * given the current clock sample.
  63  */
  64 static void bump_cpu_timer(struct k_itimer *timer, u64 now)
  65 {
  66         int i;
  67         u64 delta, incr;
  68
  69         if (timer->it.cpu.incr == 0)
  70                 return;
  71
  72         if (now < timer->it.cpu.expires)
  73                 return;
  74
  75         incr = timer->it.cpu.incr;
  76         delta = now + incr - timer->it.cpu.expires;
  77
  78         /* Don't use (incr*2 < delta), incr*2 might overflow. */
  79         for (i = 0; incr < delta - incr; i++)
  80                 incr = incr << 1;
  81
  82         for (; i >= 0; incr >>= 1, i--) {
  83                 if (delta < incr)
  84                         continue;
  85
  86                 timer->it.cpu.expires += incr;
  87                 timer->it_overrun += 1 << i;
  88                 delta -= incr;
  89         }
  90 }
  91
  92 /**
  93  * task_cputime_zero - Check a task_cputime struct for all zero fields.
  94  *
  95  * @cputime:    The struct to compare.
  96  *
  97  * Checks @cputime to see if all fields are zero.  Returns true if all fields
  98  * are zero, false if any field is nonzero.
  99  */
 100 static inline int task_cputime_zero(const struct task_cputime *cputime)
 101 {
 102         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
 103                 return 1;
 104         return 0;
 105 }
 106
 107 static inline u64 prof_ticks(struct task_struct *p)
 108 {
 109         u64 utime, stime;
 110
 111         task_cputime(p, &utime, &stime);
 112
 113         return utime + stime;
 114 }
 115 static inline u64 virt_ticks(struct task_struct *p)
 116 {
 117         u64 utime, stime;
 118
 119         task_cputime(p, &utime, &stime);
 120
 121         return utime;
 122 }
 123
 124 static int
 125 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
 126 {
 127         int error = check_clock(which_clock);
 128         if (!error) {
 129                 tp->tv_sec = 0;
 130                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
 131                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
 132                         /*
 133                          * If sched_clock is using a cycle counter, we
 134                          * don't have any idea of its true resolution
 135                          * exported, but it is much more than 1s/HZ.
 136                          */
 137                         tp->tv_nsec = 1;
 138                 }
 139         }
 140         return error;
 141 }
 142
 143 static int
 144 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec64 *tp)
 145 {
 146         /*
 147          * You can never reset a CPU clock, but we check for other errors
 148          * in the call before failing with EPERM.
 149          */
 150         int error = check_clock(which_clock);
 151         if (error == 0) {
 152                 error = -EPERM;
 153         }
 154         return error;
 155 }
 156
 157
 158 /*
 159  * Sample a per-thread clock for the given task.
 160  */
 161 static int cpu_clock_sample(const clockid_t which_clock,
 162                             struct task_struct *p, u64 *sample)
 163 {
 164         switch (CPUCLOCK_WHICH(which_clock)) {
 165         default:
 166                 return -EINVAL;
 167         case CPUCLOCK_PROF:
 168                 *sample = prof_ticks(p);
 169                 break;
 170         case CPUCLOCK_VIRT:
 171                 *sample = virt_ticks(p);
 172                 break;
 173         case CPUCLOCK_SCHED:
 174                 *sample = task_sched_runtime(p);
 175                 break;
 176         }
 177         return 0;
 178 }
 179
 180 /*
 181  * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
 182  * to avoid race conditions with concurrent updates to cputime.
 183  */
 184 static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
 185 {
 186         u64 curr_cputime;
 187 retry:
 188         curr_cputime = atomic64_read(cputime);
 189         if (sum_cputime > curr_cputime) {
 190                 if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
 191                         goto retry;
 192         }
 193 }
 194
 195 static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
 196 {
 197         __update_gt_cputime(&cputime_atomic->utime, sum->utime);
 198         __update_gt_cputime(&cputime_atomic->stime, sum->stime);
 199         __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
 200 }
 201
 202 /* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */
 203 static inline void sample_cputime_atomic(struct task_cputime *times,
 204                                          struct task_cputime_atomic *atomic_times)
 205 {
 206         times->utime = atomic64_read(&atomic_times->utime);
 207         times->stime = atomic64_read(&atomic_times->stime);
 208         times->sum_exec_runtime = atomic64_read(&atomic_times->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
 216         /* Check if cputimer isn't running. This is accessed without locking. */
 217         if (!READ_ONCE(cputimer->running)) {
 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 it.
 222                  */
 223                 thread_group_cputime(tsk, &sum);
 224                 update_gt_cputime(&cputimer->cputime_atomic, &sum);
 225
 226                 /*
 227                  * We're setting cputimer->running without a lock. Ensure
 228                  * this only gets written to in one operation. We set
 229                  * running after update_gt_cputime() as a small optimization,
 230                  * but barriers are not required because update_gt_cputime()
 231                  * can handle concurrent updates.
 232                  */
 233                 WRITE_ONCE(cputimer->running, true);
 234         }
 235         sample_cputime_atomic(times, &cputimer->cputime_atomic);
 236 }
 237
 238 /*
 239  * Sample a process (thread group) clock for the given group_leader task.
 240  * Must be called with task sighand lock held for safe while_each_thread()
 241  * traversal.
 242  */
 243 static int cpu_clock_sample_group(const clockid_t which_clock,
 244                                   struct task_struct *p,
 245                                   u64 *sample)
 246 {
 247         struct task_cputime cputime;
 248
 249         switch (CPUCLOCK_WHICH(which_clock)) {
 250         default:
 251                 return -EINVAL;
 252         case CPUCLOCK_PROF:
 253                 thread_group_cputime(p, &cputime);
 254                 *sample = cputime.utime + cputime.stime;
 255                 break;
 256         case CPUCLOCK_VIRT:
 257                 thread_group_cputime(p, &cputime);
 258                 *sample = cputime.utime;
 259                 break;
 260         case CPUCLOCK_SCHED:
 261                 thread_group_cputime(p, &cputime);
 262                 *sample = cputime.sum_exec_runtime;
 263                 break;
 264         }
 265         return 0;
 266 }
 267
 268 static int posix_cpu_clock_get_task(struct task_struct *tsk,
 269                                     const clockid_t which_clock,
 270                                     struct timespec64 *tp)
 271 {
 272         int err = -EINVAL;
 273         u64 rtn;
 274
 275         if (CPUCLOCK_PERTHREAD(which_clock)) {
 276                 if (same_thread_group(tsk, current))
 277                         err = cpu_clock_sample(which_clock, tsk, &rtn);
 278         } else {
 279                 if (tsk == current || thread_group_leader(tsk))
 280                         err = cpu_clock_sample_group(which_clock, tsk, &rtn);
 281         }
 282
 283         if (!err)
 284                 *tp = ns_to_timespec64(rtn);
 285
 286         return err;
 287 }
 288
 289
 290 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec64 *tp)
 291 {
 292         const pid_t pid = CPUCLOCK_PID(which_clock);
 293         int err = -EINVAL;
 294
 295         if (pid == 0) {
 296                 /*
 297                  * Special case constant value for our own clocks.
 298                  * We don't have to do any lookup to find ourselves.
 299                  */
 300                 err = posix_cpu_clock_get_task(current, which_clock, tp);
 301         } else {
 302                 /*
 303                  * Find the given PID, and validate that the caller
 304                  * should be able to see it.
 305                  */
 306                 struct task_struct *p;
 307                 rcu_read_lock();
 308                 p = find_task_by_vpid(pid);
 309                 if (p)
 310                         err = posix_cpu_clock_get_task(p, which_clock, tp);
 311                 rcu_read_unlock();
 312         }
 313
 314         return err;
 315 }
 316
 317 /*
 318  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
 319  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
 320  * new timer already all-zeros initialized.
 321  */
 322 static int posix_cpu_timer_create(struct k_itimer *new_timer)
 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         new_timer->kclock = &clock_posix_cpu;
 332
 333         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
 334
 335         rcu_read_lock();
 336         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
 337                 if (pid == 0) {
 338                         p = current;
 339                 } else {
 340                         p = find_task_by_vpid(pid);
 341                         if (p && !same_thread_group(p, current))
 342                                 p = NULL;
 343                 }
 344         } else {
 345                 if (pid == 0) {
 346                         p = current->group_leader;
 347                 } else {
 348                         p = find_task_by_vpid(pid);
 349                         if (p && !has_group_leader_pid(p))
 350                                 p = NULL;
 351                 }
 352         }
 353         new_timer->it.cpu.task = p;
 354         if (p) {
 355                 get_task_struct(p);
 356         } else {
 357                 ret = -EINVAL;
 358         }
 359         rcu_read_unlock();
 360
 361         return ret;
 362 }
 363
 364 /*
 365  * Clean up a CPU-clock timer that is about to be destroyed.
 366  * This is called from timer deletion with the timer already locked.
 367  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 368  * and try again.  (This happens when the timer is in the middle of firing.)
 369  */
 370 static int posix_cpu_timer_del(struct k_itimer *timer)
 371 {
 372         int ret = 0;
 373         unsigned long flags;
 374         struct sighand_struct *sighand;
 375         struct task_struct *p = timer->it.cpu.task;
 376
 377         WARN_ON_ONCE(p == NULL);
 378
 379         /*
 380          * Protect against sighand release/switch in exit/exec and process/
 381          * thread timer list entry concurrent read/writes.
 382          */
 383         sighand = lock_task_sighand(p, &flags);
 384         if (unlikely(sighand == NULL)) {
 385                 /*
 386                  * We raced with the reaping of the task.
 387                  * The deletion should have cleared us off the list.
 388                  */
 389                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
 390         } else {
 391                 if (timer->it.cpu.firing)
 392                         ret = TIMER_RETRY;
 393                 else
 394                         list_del(&timer->it.cpu.entry);
 395
 396                 unlock_task_sighand(p, &flags);
 397         }
 398
 399         if (!ret)
 400                 put_task_struct(p);
 401
 402         return ret;
 403 }
 404
 405 static void cleanup_timers_list(struct list_head *head)
 406 {
 407         struct cpu_timer_list *timer, *next;
 408
 409         list_for_each_entry_safe(timer, next, head, entry)
 410                 list_del_init(&timer->entry);
 411 }
 412
 413 /*
 414  * Clean out CPU timers still ticking when a thread exited.  The task
 415  * pointer is cleared, and the expiry time is replaced with the residual
 416  * time for later timer_gettime calls to return.
 417  * This must be called with the siglock held.
 418  */
 419 static void cleanup_timers(struct list_head *head)
 420 {
 421         cleanup_timers_list(head);
 422         cleanup_timers_list(++head);
 423         cleanup_timers_list(++head);
 424 }
 425
 426 /*
 427  * These are both called with the siglock held, when the current thread
 428  * is being reaped.  When the final (leader) thread in the group is reaped,
 429  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
 430  */
 431 void posix_cpu_timers_exit(struct task_struct *tsk)
 432 {
 433         cleanup_timers(tsk->cpu_timers);
 434 }
 435 void posix_cpu_timers_exit_group(struct task_struct *tsk)
 436 {
 437         cleanup_timers(tsk->signal->cpu_timers);
 438 }
 439
 440 static inline int expires_gt(u64 expires, u64 new_exp)
 441 {
 442         return expires == 0 || expires > new_exp;
 443 }
 444
 445 /*
 446  * Insert the timer on the appropriate list before any timers that
 447  * expire later.  This must be called with the sighand lock held.
 448  */
 449 static void arm_timer(struct k_itimer *timer)
 450 {
 451         struct task_struct *p = timer->it.cpu.task;
 452         struct list_head *head, *listpos;
 453         struct task_cputime *cputime_expires;
 454         struct cpu_timer_list *const nt = &timer->it.cpu;
 455         struct cpu_timer_list *next;
 456
 457         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 458                 head = p->cpu_timers;
 459                 cputime_expires = &p->cputime_expires;
 460         } else {
 461                 head = p->signal->cpu_timers;
 462                 cputime_expires = &p->signal->cputime_expires;
 463         }
 464         head += CPUCLOCK_WHICH(timer->it_clock);
 465
 466         listpos = head;
 467         list_for_each_entry(next, head, entry) {
 468                 if (nt->expires < next->expires)
 469                         break;
 470                 listpos = &next->entry;
 471         }
 472         list_add(&nt->entry, listpos);
 473
 474         if (listpos == head) {
 475                 u64 exp = nt->expires;
 476
 477                 /*
 478                  * We are the new earliest-expiring POSIX 1.b timer, hence
 479                  * need to update expiration cache. Take into account that
 480                  * for process timers we share expiration cache with itimers
 481                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
 482                  */
 483
 484                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
 485                 case CPUCLOCK_PROF:
 486                         if (expires_gt(cputime_expires->prof_exp, exp))
 487                                 cputime_expires->prof_exp = exp;
 488                         break;
 489                 case CPUCLOCK_VIRT:
 490                         if (expires_gt(cputime_expires->virt_exp, exp))
 491                                 cputime_expires->virt_exp = exp;
 492                         break;
 493                 case CPUCLOCK_SCHED:
 494                         if (expires_gt(cputime_expires->sched_exp, exp))
 495                                 cputime_expires->sched_exp = exp;
 496                         break;
 497                 }
 498                 if (CPUCLOCK_PERTHREAD(timer->it_clock))
 499                         tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
 500                 else
 501                         tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
 502         }
 503 }
 504
 505 /*
 506  * The timer is locked, fire it and arrange for its reload.
 507  */
 508 static void cpu_timer_fire(struct k_itimer *timer)
 509 {
 510         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
 511                 /*
 512                  * User don't want any signal.
 513                  */
 514                 timer->it.cpu.expires = 0;
 515         } else if (unlikely(timer->sigq == NULL)) {
 516                 /*
 517                  * This a special case for clock_nanosleep,
 518                  * not a normal timer from sys_timer_create.
 519                  */
 520                 wake_up_process(timer->it_process);
 521                 timer->it.cpu.expires = 0;
 522         } else if (timer->it.cpu.incr == 0) {
 523                 /*
 524                  * One-shot timer.  Clear it as soon as it's fired.
 525                  */
 526                 posix_timer_event(timer, 0);
 527                 timer->it.cpu.expires = 0;
 528         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
 529                 /*
 530                  * The signal did not get queued because the signal
 531                  * was ignored, so we won't get any callback to
 532                  * reload the timer.  But we need to keep it
 533                  * ticking in case the signal is deliverable next time.
 534                  */
 535                 posix_cpu_timer_rearm(timer);
 536                 ++timer->it_requeue_pending;
 537         }
 538 }
 539
 540 /*
 541  * Sample a process (thread group) timer for the given group_leader task.
 542  * Must be called with task sighand lock held for safe while_each_thread()
 543  * traversal.
 544  */
 545 static int cpu_timer_sample_group(const clockid_t which_clock,
 546                                   struct task_struct *p, u64 *sample)
 547 {
 548         struct task_cputime cputime;
 549
 550         thread_group_cputimer(p, &cputime);
 551         switch (CPUCLOCK_WHICH(which_clock)) {
 552         default:
 553                 return -EINVAL;
 554         case CPUCLOCK_PROF:
 555                 *sample = cputime.utime + cputime.stime;
 556                 break;
 557         case CPUCLOCK_VIRT:
 558                 *sample = cputime.utime;
 559                 break;
 560         case CPUCLOCK_SCHED:
 561                 *sample = cputime.sum_exec_runtime;
 562                 break;
 563         }
 564         return 0;
 565 }
 566
 567 /*
 568  * Guts of sys_timer_settime for CPU timers.
 569  * This is called with the timer locked and interrupts disabled.
 570  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 571  * and try again.  (This happens when the timer is in the middle of firing.)
 572  */
 573 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 574                                struct itimerspec64 *new, struct itimerspec64 *old)
 575 {
 576         unsigned long flags;
 577         struct sighand_struct *sighand;
 578         struct task_struct *p = timer->it.cpu.task;
 579         u64 old_expires, new_expires, old_incr, val;
 580         int ret;
 581
 582         WARN_ON_ONCE(p == NULL);
 583
 584         /*
 585          * Use the to_ktime conversion because that clamps the maximum
 586          * value to KTIME_MAX and avoid multiplication overflows.
 587          */
 588         new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
 589
 590         /*
 591          * Protect against sighand release/switch in exit/exec and p->cpu_timers
 592          * and p->signal->cpu_timers read/write in arm_timer()
 593          */
 594         sighand = lock_task_sighand(p, &flags);
 595         /*
 596          * If p has just been reaped, we can no
 597          * longer get any information about it at all.
 598          */
 599         if (unlikely(sighand == NULL)) {
 600                 return -ESRCH;
 601         }
 602
 603         /*
 604          * Disarm any old timer after extracting its expiry time.
 605          */
 606         lockdep_assert_irqs_disabled();
 607
 608         ret = 0;
 609         old_incr = timer->it.cpu.incr;
 610         old_expires = timer->it.cpu.expires;
 611         if (unlikely(timer->it.cpu.firing)) {
 612                 timer->it.cpu.firing = -1;
 613                 ret = TIMER_RETRY;
 614         } else
 615                 list_del_init(&timer->it.cpu.entry);
 616
 617         /*
 618          * We need to sample the current value to convert the new
 619          * value from to relative and absolute, and to convert the
 620          * old value from absolute to relative.  To set a process
 621          * timer, we need a sample to balance the thread expiry
 622          * times (in arm_timer).  With an absolute time, we must
 623          * check if it's already passed.  In short, we need a sample.
 624          */
 625         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 626                 cpu_clock_sample(timer->it_clock, p, &val);
 627         } else {
 628                 cpu_timer_sample_group(timer->it_clock, p, &val);
 629         }
 630
 631         if (old) {
 632                 if (old_expires == 0) {
 633                         old->it_value.tv_sec = 0;
 634                         old->it_value.tv_nsec = 0;
 635                 } else {
 636                         /*
 637                          * Update the timer in case it has
 638                          * overrun already.  If it has,
 639                          * we'll report it as having overrun
 640                          * and with the next reloaded timer
 641                          * already ticking, though we are
 642                          * swallowing that pending
 643                          * notification here to install the
 644                          * new setting.
 645                          */
 646                         bump_cpu_timer(timer, val);
 647                         if (val < timer->it.cpu.expires) {
 648                                 old_expires = timer->it.cpu.expires - val;
 649                                 old->it_value = ns_to_timespec64(old_expires);
 650                         } else {
 651                                 old->it_value.tv_nsec = 1;
 652                                 old->it_value.tv_sec = 0;
 653                         }
 654                 }
 655         }
 656
 657         if (unlikely(ret)) {
 658                 /*
 659                  * We are colliding with the timer actually firing.
 660                  * Punt after filling in the timer's old value, and
 661                  * disable this firing since we are already reporting
 662                  * it as an overrun (thanks to bump_cpu_timer above).
 663                  */
 664                 unlock_task_sighand(p, &flags);
 665                 goto out;
 666         }
 667
 668         if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
 669                 new_expires += val;
 670         }
 671
 672         /*
 673          * Install the new expiry time (or zero).
 674          * For a timer with no notification action, we don't actually
 675          * arm the timer (we'll just fake it for timer_gettime).
 676          */
 677         timer->it.cpu.expires = new_expires;
 678         if (new_expires != 0 && val < new_expires) {
 679                 arm_timer(timer);
 680         }
 681
 682         unlock_task_sighand(p, &flags);
 683         /*
 684          * Install the new reload setting, and
 685          * set up the signal and overrun bookkeeping.
 686          */
 687         timer->it.cpu.incr = timespec64_to_ns(&new->it_interval);
 688
 689         /*
 690          * This acts as a modification timestamp for the timer,
 691          * so any automatic reload attempt will punt on seeing
 692          * that we have reset the timer manually.
 693          */
 694         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
 695                 ~REQUEUE_PENDING;
 696         timer->it_overrun_last = 0;
 697         timer->it_overrun = -1;
 698
 699         if (new_expires != 0 && !(val < new_expires)) {
 700                 /*
 701                  * The designated time already passed, so we notify
 702                  * immediately, even if the thread never runs to
 703                  * accumulate more time on this clock.
 704                  */
 705                 cpu_timer_fire(timer);
 706         }
 707
 708         ret = 0;
 709  out:
 710         if (old)
 711                 old->it_interval = ns_to_timespec64(old_incr);
 712
 713         return ret;
 714 }
 715
 716 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
 717 {
 718         u64 now;
 719         struct task_struct *p = timer->it.cpu.task;
 720
 721         WARN_ON_ONCE(p == NULL);
 722
 723         /*
 724          * Easy part: convert the reload time.
 725          */
 726         itp->it_interval = ns_to_timespec64(timer->it.cpu.incr);
 727
 728         if (!timer->it.cpu.expires)
 729                 return;
 730
 731         /*
 732          * Sample the clock to take the difference with the expiry time.
 733          */
 734         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 735                 cpu_clock_sample(timer->it_clock, p, &now);
 736         } else {
 737                 struct sighand_struct *sighand;
 738                 unsigned long flags;
 739
 740                 /*
 741                  * Protect against sighand release/switch in exit/exec and
 742                  * also make timer sampling safe if it ends up calling
 743                  * thread_group_cputime().
 744                  */
 745                 sighand = lock_task_sighand(p, &flags);
 746                 if (unlikely(sighand == NULL)) {
 747                         /*
 748                          * The process has been reaped.
 749                          * We can't even collect a sample any more.
 750                          * Call the timer disarmed, nothing else to do.
 751                          */
 752                         timer->it.cpu.expires = 0;
 753                         return;
 754                 } else {
 755                         cpu_timer_sample_group(timer->it_clock, p, &now);
 756                         unlock_task_sighand(p, &flags);
 757                 }
 758         }
 759
 760         if (now < timer->it.cpu.expires) {
 761                 itp->it_value = ns_to_timespec64(timer->it.cpu.expires - now);
 762         } else {
 763                 /*
 764                  * The timer should have expired already, but the firing
 765                  * hasn't taken place yet.  Say it's just about to expire.
 766                  */
 767                 itp->it_value.tv_nsec = 1;
 768                 itp->it_value.tv_sec = 0;
 769         }
 770 }
 771
 772 static unsigned long long
 773 check_timers_list(struct list_head *timers,
 774                   struct list_head *firing,
 775                   unsigned long long curr)
 776 {
 777         int maxfire = 20;
 778
 779         while (!list_empty(timers)) {
 780                 struct cpu_timer_list *t;
 781
 782                 t = list_first_entry(timers, struct cpu_timer_list, entry);
 783
 784                 if (!--maxfire || curr < t->expires)
 785                         return t->expires;
 786
 787                 t->firing = 1;
 788                 list_move_tail(&t->entry, firing);
 789         }
 790
 791         return 0;
 792 }
 793
 794 /*
 795  * Check for any per-thread CPU timers that have fired and move them off
 796  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
 797  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
 798  */
 799 static void check_thread_timers(struct task_struct *tsk,
 800                                 struct list_head *firing)
 801 {
 802         struct list_head *timers = tsk->cpu_timers;
 803         struct task_cputime *tsk_expires = &tsk->cputime_expires;
 804         u64 expires;
 805         unsigned long soft;
 806
 807         /*
 808          * If cputime_expires is zero, then there are no active
 809          * per thread CPU timers.
 810          */
 811         if (task_cputime_zero(&tsk->cputime_expires))
 812                 return;
 813
 814         expires = check_timers_list(timers, firing, prof_ticks(tsk));
 815         tsk_expires->prof_exp = expires;
 816
 817         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
 818         tsk_expires->virt_exp = expires;
 819
 820         tsk_expires->sched_exp = check_timers_list(++timers, firing,
 821                                                    tsk->se.sum_exec_runtime);
 822
 823         /*
 824          * Check for the special case thread timers.
 825          */
 826         soft = task_rlimit(tsk, RLIMIT_RTTIME);
 827         if (soft != RLIM_INFINITY) {
 828                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
 829
 830                 if (hard != RLIM_INFINITY &&
 831                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
 832                         /*
 833                          * At the hard limit, we just die.
 834                          * No need to calculate anything else now.
 835                          */
 836                         if (print_fatal_signals) {
 837                                 pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
 838                                         tsk->comm, task_pid_nr(tsk));
 839                         }
 840                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 841                         return;
 842                 }
 843                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
 844                         /*
 845                          * At the soft limit, send a SIGXCPU every second.
 846                          */
 847                         if (soft < hard) {
 848                                 soft += USEC_PER_SEC;
 849                                 tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur =
 850                                         soft;
 851                         }
 852                         if (print_fatal_signals) {
 853                                 pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
 854                                         tsk->comm, task_pid_nr(tsk));
 855                         }
 856                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 857                 }
 858         }
 859         if (task_cputime_zero(tsk_expires))
 860                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 861 }
 862
 863 static inline void stop_process_timers(struct signal_struct *sig)
 864 {
 865         struct thread_group_cputimer *cputimer = &sig->cputimer;
 866
 867         /* Turn off cputimer->running. This is done without locking. */
 868         WRITE_ONCE(cputimer->running, false);
 869         tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
 870 }
 871
 872 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 873                              u64 *expires, u64 cur_time, int signo)
 874 {
 875         if (!it->expires)
 876                 return;
 877
 878         if (cur_time >= it->expires) {
 879                 if (it->incr)
 880                         it->expires += it->incr;
 881                 else
 882                         it->expires = 0;
 883
 884                 trace_itimer_expire(signo == SIGPROF ?
 885                                     ITIMER_PROF : ITIMER_VIRTUAL,
 886                                     tsk->signal->leader_pid, cur_time);
 887                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
 888         }
 889
 890         if (it->expires && (!*expires || it->expires < *expires))
 891                 *expires = it->expires;
 892 }
 893
 894 /*
 895  * Check for any per-thread CPU timers that have fired and move them
 896  * off the tsk->*_timers list onto the firing list.  Per-thread timers
 897  * have already been taken off.
 898  */
 899 static void check_process_timers(struct task_struct *tsk,
 900                                  struct list_head *firing)
 901 {
 902         struct signal_struct *const sig = tsk->signal;
 903         u64 utime, ptime, virt_expires, prof_expires;
 904         u64 sum_sched_runtime, sched_expires;
 905         struct list_head *timers = sig->cpu_timers;
 906         struct task_cputime cputime;
 907         unsigned long soft;
 908
 909         /*
 910          * If cputimer is not running, then there are no active
 911          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
 912          */
 913         if (!READ_ONCE(tsk->signal->cputimer.running))
 914                 return;
 915
 916         /*
 917          * Signify that a thread is checking for process timers.
 918          * Write access to this field is protected by the sighand lock.
 919          */
 920         sig->cputimer.checking_timer = true;
 921
 922         /*
 923          * Collect the current process totals.
 924          */
 925         thread_group_cputimer(tsk, &cputime);
 926         utime = cputime.utime;
 927         ptime = utime + cputime.stime;
 928         sum_sched_runtime = cputime.sum_exec_runtime;
 929
 930         prof_expires = check_timers_list(timers, firing, ptime);
 931         virt_expires = check_timers_list(++timers, firing, utime);
 932         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
 933
 934         /*
 935          * Check for the special case process timers.
 936          */
 937         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
 938                          SIGPROF);
 939         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
 940                          SIGVTALRM);
 941         soft = task_rlimit(tsk, RLIMIT_CPU);
 942         if (soft != RLIM_INFINITY) {
 943                 unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
 944                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
 945                 u64 x;
 946                 if (psecs >= hard) {
 947                         /*
 948                          * At the hard limit, we just die.
 949                          * No need to calculate anything else now.
 950                          */
 951                         if (print_fatal_signals) {
 952                                 pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
 953                                         tsk->comm, task_pid_nr(tsk));
 954                         }
 955                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 956                         return;
 957                 }
 958                 if (psecs >= soft) {
 959                         /*
 960                          * At the soft limit, send a SIGXCPU every second.
 961                          */
 962                         if (print_fatal_signals) {
 963                                 pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
 964                                         tsk->comm, task_pid_nr(tsk));
 965                         }
 966                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 967                         if (soft < hard) {
 968                                 soft++;
 969                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
 970                         }
 971                 }
 972                 x = soft * NSEC_PER_SEC;
 973                 if (!prof_expires || x < prof_expires)
 974                         prof_expires = x;
 975         }
 976
 977         sig->cputime_expires.prof_exp = prof_expires;
 978         sig->cputime_expires.virt_exp = virt_expires;
 979         sig->cputime_expires.sched_exp = sched_expires;
 980         if (task_cputime_zero(&sig->cputime_expires))
 981                 stop_process_timers(sig);
 982
 983         sig->cputimer.checking_timer = false;
 984 }
 985
 986 /*
 987  * This is called from the signal code (via posixtimer_rearm)
 988  * when the last timer signal was delivered and we have to reload the timer.
 989  */
 990 static void posix_cpu_timer_rearm(struct k_itimer *timer)
 991 {
 992         struct sighand_struct *sighand;
 993         unsigned long flags;
 994         struct task_struct *p = timer->it.cpu.task;
 995         u64 now;
 996
 997         WARN_ON_ONCE(p == NULL);
 998
 999         /*
1000          * Fetch the current sample and update the timer's expiry time.
1001          */
1002         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1003                 cpu_clock_sample(timer->it_clock, p, &now);
1004                 bump_cpu_timer(timer, now);
1005                 if (unlikely(p->exit_state))
1006                         return;
1007
1008                 /* Protect timer list r/w in arm_timer() */
1009                 sighand = lock_task_sighand(p, &flags);
1010                 if (!sighand)
1011                         return;
1012         } else {
1013                 /*
1014                  * Protect arm_timer() and timer sampling in case of call to
1015                  * thread_group_cputime().
1016                  */
1017                 sighand = lock_task_sighand(p, &flags);
1018                 if (unlikely(sighand == NULL)) {
1019                         /*
1020                          * The process has been reaped.
1021                          * We can't even collect a sample any more.
1022                          */
1023                         timer->it.cpu.expires = 0;
1024                         return;
1025                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1026                         /* If the process is dying, no need to rearm */
1027                         goto unlock;
1028                 }
1029                 cpu_timer_sample_group(timer->it_clock, p, &now);
1030                 bump_cpu_timer(timer, now);
1031                 /* Leave the sighand locked for the call below.  */
1032         }
1033
1034         /*
1035          * Now re-arm for the new expiry time.
1036          */
1037         lockdep_assert_irqs_disabled();
1038         arm_timer(timer);
1039 unlock:
1040         unlock_task_sighand(p, &flags);
1041 }
1042
1043 /**
1044  * task_cputime_expired - Compare two task_cputime entities.
1045  *
1046  * @sample:     The task_cputime structure to be checked for expiration.
1047  * @expires:    Expiration times, against which @sample will be checked.
1048  *
1049  * Checks @sample against @expires to see if any field of @sample has expired.
1050  * Returns true if any field of the former is greater than the corresponding
1051  * field of the latter if the latter field is set.  Otherwise returns false.
1052  */
1053 static inline int task_cputime_expired(const struct task_cputime *sample,
1054                                         const struct task_cputime *expires)
1055 {
1056         if (expires->utime && sample->utime >= expires->utime)
1057                 return 1;
1058         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1059                 return 1;
1060         if (expires->sum_exec_runtime != 0 &&
1061             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1062                 return 1;
1063         return 0;
1064 }
1065
1066 /**
1067  * fastpath_timer_check - POSIX CPU timers fast path.
1068  *
1069  * @tsk:        The task (thread) being checked.
1070  *
1071  * Check the task and thread group timers.  If both are zero (there are no
1072  * timers set) return false.  Otherwise snapshot the task and thread group
1073  * timers and compare them with the corresponding expiration times.  Return
1074  * true if a timer has expired, else return false.
1075  */
1076 static inline int fastpath_timer_check(struct task_struct *tsk)
1077 {
1078         struct signal_struct *sig;
1079
1080         if (!task_cputime_zero(&tsk->cputime_expires)) {
1081                 struct task_cputime task_sample;
1082
1083                 task_cputime(tsk, &task_sample.utime, &task_sample.stime);
1084                 task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
1085                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1086                         return 1;
1087         }
1088
1089         sig = tsk->signal;
1090         /*
1091          * Check if thread group timers expired when the cputimer is
1092          * running and no other thread in the group is already checking
1093          * for thread group cputimers. These fields are read without the
1094          * sighand lock. However, this is fine because this is meant to
1095          * be a fastpath heuristic to determine whether we should try to
1096          * acquire the sighand lock to check/handle timers.
1097          *
1098          * In the worst case scenario, if 'running' or 'checking_timer' gets
1099          * set but the current thread doesn't see the change yet, we'll wait
1100          * until the next thread in the group gets a scheduler interrupt to
1101          * handle the timer. This isn't an issue in practice because these
1102          * types of delays with signals actually getting sent are expected.
1103          */
1104         if (READ_ONCE(sig->cputimer.running) &&
1105             !READ_ONCE(sig->cputimer.checking_timer)) {
1106                 struct task_cputime group_sample;
1107
1108                 sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
1109
1110                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1111                         return 1;
1112         }
1113
1114         return 0;
1115 }
1116
1117 /*
1118  * This is called from the timer interrupt handler.  The irq handler has
1119  * already updated our counts.  We need to check if any timers fire now.
1120  * Interrupts are disabled.
1121  */
1122 void run_posix_cpu_timers(struct task_struct *tsk)
1123 {
1124         LIST_HEAD(firing);
1125         struct k_itimer *timer, *next;
1126         unsigned long flags;
1127
1128         lockdep_assert_irqs_disabled();
1129
1130         /*
1131          * The fast path checks that there are no expired thread or thread
1132          * group timers.  If that's so, just return.
1133          */
1134         if (!fastpath_timer_check(tsk))
1135                 return;
1136
1137         if (!lock_task_sighand(tsk, &flags))
1138                 return;
1139         /*
1140          * Here we take off tsk->signal->cpu_timers[N] and
1141          * tsk->cpu_timers[N] all the timers that are firing, and
1142          * put them on the firing list.
1143          */
1144         check_thread_timers(tsk, &firing);
1145
1146         check_process_timers(tsk, &firing);
1147
1148         /*
1149          * We must release these locks before taking any timer's lock.
1150          * There is a potential race with timer deletion here, as the
1151          * siglock now protects our private firing list.  We have set
1152          * the firing flag in each timer, so that a deletion attempt
1153          * that gets the timer lock before we do will give it up and
1154          * spin until we've taken care of that timer below.
1155          */
1156         unlock_task_sighand(tsk, &flags);
1157
1158         /*
1159          * Now that all the timers on our list have the firing flag,
1160          * no one will touch their list entries but us.  We'll take
1161          * each timer's lock before clearing its firing flag, so no
1162          * timer call will interfere.
1163          */
1164         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1165                 int cpu_firing;
1166
1167                 spin_lock(&timer->it_lock);
1168                 list_del_init(&timer->it.cpu.entry);
1169                 cpu_firing = timer->it.cpu.firing;
1170                 timer->it.cpu.firing = 0;
1171                 /*
1172                  * The firing flag is -1 if we collided with a reset
1173                  * of the timer, which already reported this
1174                  * almost-firing as an overrun.  So don't generate an event.
1175                  */
1176                 if (likely(cpu_firing >= 0))
1177                         cpu_timer_fire(timer);
1178                 spin_unlock(&timer->it_lock);
1179         }
1180 }
1181
1182 /*
1183  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1184  * The tsk->sighand->siglock must be held by the caller.
1185  */
1186 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1187                            u64 *newval, u64 *oldval)
1188 {
1189         u64 now;
1190
1191         WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
1192         cpu_timer_sample_group(clock_idx, tsk, &now);
1193
1194         if (oldval) {
1195                 /*
1196                  * We are setting itimer. The *oldval is absolute and we update
1197                  * it to be relative, *newval argument is relative and we update
1198                  * it to be absolute.
1199                  */
1200                 if (*oldval) {
1201                         if (*oldval <= now) {
1202                                 /* Just about to fire. */
1203                                 *oldval = TICK_NSEC;
1204                         } else {
1205                                 *oldval -= now;
1206                         }
1207                 }
1208
1209                 if (!*newval)
1210                         return;
1211                 *newval += now;
1212         }
1213
1214         /*
1215          * Update expiration cache if we are the earliest timer, or eventually
1216          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1217          */
1218         switch (clock_idx) {
1219         case CPUCLOCK_PROF:
1220                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1221                         tsk->signal->cputime_expires.prof_exp = *newval;
1222                 break;
1223         case CPUCLOCK_VIRT:
1224                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1225                         tsk->signal->cputime_expires.virt_exp = *newval;
1226                 break;
1227         }
1228
1229         tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1230 }
1231
1232 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1233                             const struct timespec64 *rqtp)
1234 {
1235         struct itimerspec64 it;
1236         struct k_itimer timer;
1237         u64 expires;
1238         int error;
1239
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) {
1250                 static struct itimerspec64 zero_it;
1251                 struct restart_block *restart;
1252
1253                 memset(&it, 0, sizeof(it));
1254                 it.it_value = *rqtp;
1255
1256                 spin_lock_irq(&timer.it_lock);
1257                 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1258                 if (error) {
1259                         spin_unlock_irq(&timer.it_lock);
1260                         return error;
1261                 }
1262
1263                 while (!signal_pending(current)) {
1264                         if (timer.it.cpu.expires == 0) {
1265                                 /*
1266                                  * Our timer fired and was reset, below
1267                                  * deletion can not fail.
1268                                  */
1269                                 posix_cpu_timer_del(&timer);
1270                                 spin_unlock_irq(&timer.it_lock);
1271                                 return 0;
1272                         }
1273
1274                         /*
1275                          * Block until cpu_timer_fire (or a signal) wakes us.
1276                          */
1277                         __set_current_state(TASK_INTERRUPTIBLE);
1278                         spin_unlock_irq(&timer.it_lock);
1279                         schedule();
1280                         spin_lock_irq(&timer.it_lock);
1281                 }
1282
1283                 /*
1284                  * We were interrupted by a signal.
1285                  */
1286                 expires = timer.it.cpu.expires;
1287                 error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1288                 if (!error) {
1289                         /*
1290                          * Timer is now unarmed, deletion can not fail.
1291                          */
1292                         posix_cpu_timer_del(&timer);
1293                 }
1294                 spin_unlock_irq(&timer.it_lock);
1295
1296                 while (error == TIMER_RETRY) {
1297                         /*
1298                          * We need to handle case when timer was or is in the
1299                          * middle of firing. In other cases we already freed
1300                          * resources.
1301                          */
1302                         spin_lock_irq(&timer.it_lock);
1303                         error = posix_cpu_timer_del(&timer);
1304                         spin_unlock_irq(&timer.it_lock);
1305                 }
1306
1307                 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1308                         /*
1309                          * It actually did fire already.
1310                          */
1311                         return 0;
1312                 }
1313
1314                 error = -ERESTART_RESTARTBLOCK;
1315                 /*
1316                  * Report back to the user the time still remaining.
1317                  */
1318                 restart = &current->restart_block;
1319                 restart->nanosleep.expires = expires;
1320                 if (restart->nanosleep.type != TT_NONE)
1321                         error = nanosleep_copyout(restart, &it.it_value);
1322         }
1323
1324         return error;
1325 }
1326
1327 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1328
1329 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1330                             const struct timespec64 *rqtp)
1331 {
1332         struct restart_block *restart_block = &current->restart_block;
1333         int error;
1334
1335         /*
1336          * Diagnose required errors first.
1337          */
1338         if (CPUCLOCK_PERTHREAD(which_clock) &&
1339             (CPUCLOCK_PID(which_clock) == 0 ||
1340              CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1341                 return -EINVAL;
1342
1343         error = do_cpu_nanosleep(which_clock, flags, rqtp);
1344
1345         if (error == -ERESTART_RESTARTBLOCK) {
1346
1347                 if (flags & TIMER_ABSTIME)
1348                         return -ERESTARTNOHAND;
1349
1350                 restart_block->fn = posix_cpu_nsleep_restart;
1351                 restart_block->nanosleep.clockid = which_clock;
1352         }
1353         return error;
1354 }
1355
1356 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1357 {
1358         clockid_t which_clock = restart_block->nanosleep.clockid;
1359         struct timespec64 t;
1360
1361         t = ns_to_timespec64(restart_block->nanosleep.expires);
1362
1363         return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1364 }
1365
1366 #define PROCESS_CLOCK   MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
1367 #define THREAD_CLOCK    MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
1368
1369 static int process_cpu_clock_getres(const clockid_t which_clock,
1370                                     struct timespec64 *tp)
1371 {
1372         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1373 }
1374 static int process_cpu_clock_get(const clockid_t which_clock,
1375                                  struct timespec64 *tp)
1376 {
1377         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1378 }
1379 static int process_cpu_timer_create(struct k_itimer *timer)
1380 {
1381         timer->it_clock = PROCESS_CLOCK;
1382         return posix_cpu_timer_create(timer);
1383 }
1384 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1385                               const struct timespec64 *rqtp)
1386 {
1387         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1388 }
1389 static int thread_cpu_clock_getres(const clockid_t which_clock,
1390                                    struct timespec64 *tp)
1391 {
1392         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1393 }
1394 static int thread_cpu_clock_get(const clockid_t which_clock,
1395                                 struct timespec64 *tp)
1396 {
1397         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1398 }
1399 static int thread_cpu_timer_create(struct k_itimer *timer)
1400 {
1401         timer->it_clock = THREAD_CLOCK;
1402         return posix_cpu_timer_create(timer);
1403 }
1404
1405 const struct k_clock clock_posix_cpu = {
1406         .clock_getres   = posix_cpu_clock_getres,
1407         .clock_set      = posix_cpu_clock_set,
1408         .clock_get      = posix_cpu_clock_get,
1409         .timer_create   = posix_cpu_timer_create,
1410         .nsleep         = posix_cpu_nsleep,
1411         .timer_set      = posix_cpu_timer_set,
1412         .timer_del      = posix_cpu_timer_del,
1413         .timer_get      = posix_cpu_timer_get,
1414         .timer_rearm    = posix_cpu_timer_rearm,
1415 };
1416
1417 const struct k_clock clock_process = {
1418         .clock_getres   = process_cpu_clock_getres,
1419         .clock_get      = process_cpu_clock_get,
1420         .timer_create   = process_cpu_timer_create,
1421         .nsleep         = process_cpu_nsleep,
1422 };
1423
1424 const struct k_clock clock_thread = {
1425         .clock_getres   = thread_cpu_clock_getres,
1426         .clock_get      = thread_cpu_clock_get,
1427         .timer_create   = thread_cpu_timer_create,
1428 };