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 #include <linux/sched/deadline.h>
  18
  19 #include "posix-timers.h"
  20
  21 static void posix_cpu_timer_rearm(struct k_itimer *timer);
  22
  23 /*
  24  * Called after updating RLIMIT_CPU to run cpu timer and update
  25  * tsk->signal->cputime_expires expiration cache if necessary. Needs
  26  * siglock protection since other code may update expiration cache as
  27  * well.
  28  */
  29 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
  30 {
  31         u64 nsecs = rlim_new * NSEC_PER_SEC;
  32
  33         spin_lock_irq(&task->sighand->siglock);
  34         set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
  35         spin_unlock_irq(&task->sighand->siglock);
  36 }
  37
  38 static int check_clock(const clockid_t which_clock)
  39 {
  40         int error = 0;
  41         struct task_struct *p;
  42         const pid_t pid = CPUCLOCK_PID(which_clock);
  43
  44         if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
  45                 return -EINVAL;
  46
  47         if (pid == 0)
  48                 return 0;
  49
  50         rcu_read_lock();
  51         p = find_task_by_vpid(pid);
  52         if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
  53                    same_thread_group(p, current) : has_group_leader_pid(p))) {
  54                 error = -EINVAL;
  55         }
  56         rcu_read_unlock();
  57
  58         return error;
  59 }
  60
  61 /*
  62  * Update expiry time from increment, and increase overrun count,
  63  * given the current clock sample.
  64  */
  65 static void bump_cpu_timer(struct k_itimer *timer, u64 now)
  66 {
  67         int i;
  68         u64 delta, incr;
  69
  70         if (timer->it.cpu.incr == 0)
  71                 return;
  72
  73         if (now < timer->it.cpu.expires)
  74                 return;
  75
  76         incr = timer->it.cpu.incr;
  77         delta = now + incr - timer->it.cpu.expires;
  78
  79         /* Don't use (incr*2 < delta), incr*2 might overflow. */
  80         for (i = 0; incr < delta - incr; i++)
  81                 incr = incr << 1;
  82
  83         for (; i >= 0; incr >>= 1, i--) {
  84                 if (delta < incr)
  85                         continue;
  86
  87                 timer->it.cpu.expires += incr;
  88                 timer->it_overrun += 1LL << i;
  89                 delta -= incr;
  90         }
  91 }
  92
  93 /**
  94  * task_cputime_zero - Check a task_cputime struct for all zero fields.
  95  *
  96  * @cputime:    The struct to compare.
  97  *
  98  * Checks @cputime to see if all fields are zero.  Returns true if all fields
  99  * are zero, false if any field is nonzero.
 100  */
 101 static inline int task_cputime_zero(const struct task_cputime *cputime)
 102 {
 103         if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
 104                 return 1;
 105         return 0;
 106 }
 107
 108 static inline u64 prof_ticks(struct task_struct *p)
 109 {
 110         u64 utime, stime;
 111
 112         task_cputime(p, &utime, &stime);
 113
 114         return utime + stime;
 115 }
 116 static inline u64 virt_ticks(struct task_struct *p)
 117 {
 118         u64 utime, stime;
 119
 120         task_cputime(p, &utime, &stime);
 121
 122         return utime;
 123 }
 124
 125 static int
 126 posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
 127 {
 128         int error = check_clock(which_clock);
 129         if (!error) {
 130                 tp->tv_sec = 0;
 131                 tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
 132                 if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
 133                         /*
 134                          * If sched_clock is using a cycle counter, we
 135                          * don't have any idea of its true resolution
 136                          * exported, but it is much more than 1s/HZ.
 137                          */
 138                         tp->tv_nsec = 1;
 139                 }
 140         }
 141         return error;
 142 }
 143
 144 static int
 145 posix_cpu_clock_set(const clockid_t which_clock, const struct timespec64 *tp)
 146 {
 147         /*
 148          * You can never reset a CPU clock, but we check for other errors
 149          * in the call before failing with EPERM.
 150          */
 151         int error = check_clock(which_clock);
 152         if (error == 0) {
 153                 error = -EPERM;
 154         }
 155         return error;
 156 }
 157
 158
 159 /*
 160  * Sample a per-thread clock for the given task.
 161  */
 162 static int cpu_clock_sample(const clockid_t which_clock,
 163                             struct task_struct *p, u64 *sample)
 164 {
 165         switch (CPUCLOCK_WHICH(which_clock)) {
 166         default:
 167                 return -EINVAL;
 168         case CPUCLOCK_PROF:
 169                 *sample = prof_ticks(p);
 170                 break;
 171         case CPUCLOCK_VIRT:
 172                 *sample = virt_ticks(p);
 173                 break;
 174         case CPUCLOCK_SCHED:
 175                 *sample = task_sched_runtime(p);
 176                 break;
 177         }
 178         return 0;
 179 }
 180
 181 /*
 182  * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
 183  * to avoid race conditions with concurrent updates to cputime.
 184  */
 185 static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
 186 {
 187         u64 curr_cputime;
 188 retry:
 189         curr_cputime = atomic64_read(cputime);
 190         if (sum_cputime > curr_cputime) {
 191                 if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
 192                         goto retry;
 193         }
 194 }
 195
 196 static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum)
 197 {
 198         __update_gt_cputime(&cputime_atomic->utime, sum->utime);
 199         __update_gt_cputime(&cputime_atomic->stime, sum->stime);
 200         __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
 201 }
 202
 203 /* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */
 204 static inline void sample_cputime_atomic(struct task_cputime *times,
 205                                          struct task_cputime_atomic *atomic_times)
 206 {
 207         times->utime = atomic64_read(&atomic_times->utime);
 208         times->stime = atomic64_read(&atomic_times->stime);
 209         times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime);
 210 }
 211
 212 void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 213 {
 214         struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 215         struct task_cputime sum;
 216
 217         /* Check if cputimer isn't running. This is accessed without locking. */
 218         if (!READ_ONCE(cputimer->running)) {
 219                 /*
 220                  * The POSIX timer interface allows for absolute time expiry
 221                  * values through the TIMER_ABSTIME flag, therefore we have
 222                  * to synchronize the timer to the clock every time we start it.
 223                  */
 224                 thread_group_cputime(tsk, &sum);
 225                 update_gt_cputime(&cputimer->cputime_atomic, &sum);
 226
 227                 /*
 228                  * We're setting cputimer->running without a lock. Ensure
 229                  * this only gets written to in one operation. We set
 230                  * running after update_gt_cputime() as a small optimization,
 231                  * but barriers are not required because update_gt_cputime()
 232                  * can handle concurrent updates.
 233                  */
 234                 WRITE_ONCE(cputimer->running, true);
 235         }
 236         sample_cputime_atomic(times, &cputimer->cputime_atomic);
 237 }
 238
 239 /*
 240  * Sample a process (thread group) clock for the given group_leader task.
 241  * Must be called with task sighand lock held for safe while_each_thread()
 242  * traversal.
 243  */
 244 static int cpu_clock_sample_group(const clockid_t which_clock,
 245                                   struct task_struct *p,
 246                                   u64 *sample)
 247 {
 248         struct task_cputime cputime;
 249
 250         switch (CPUCLOCK_WHICH(which_clock)) {
 251         default:
 252                 return -EINVAL;
 253         case CPUCLOCK_PROF:
 254                 thread_group_cputime(p, &cputime);
 255                 *sample = cputime.utime + cputime.stime;
 256                 break;
 257         case CPUCLOCK_VIRT:
 258                 thread_group_cputime(p, &cputime);
 259                 *sample = cputime.utime;
 260                 break;
 261         case CPUCLOCK_SCHED:
 262                 thread_group_cputime(p, &cputime);
 263                 *sample = cputime.sum_exec_runtime;
 264                 break;
 265         }
 266         return 0;
 267 }
 268
 269 static int posix_cpu_clock_get_task(struct task_struct *tsk,
 270                                     const clockid_t which_clock,
 271                                     struct timespec64 *tp)
 272 {
 273         int err = -EINVAL;
 274         u64 rtn;
 275
 276         if (CPUCLOCK_PERTHREAD(which_clock)) {
 277                 if (same_thread_group(tsk, current))
 278                         err = cpu_clock_sample(which_clock, tsk, &rtn);
 279         } else {
 280                 if (tsk == current || thread_group_leader(tsk))
 281                         err = cpu_clock_sample_group(which_clock, tsk, &rtn);
 282         }
 283
 284         if (!err)
 285                 *tp = ns_to_timespec64(rtn);
 286
 287         return err;
 288 }
 289
 290
 291 static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec64 *tp)
 292 {
 293         const pid_t pid = CPUCLOCK_PID(which_clock);
 294         int err = -EINVAL;
 295
 296         if (pid == 0) {
 297                 /*
 298                  * Special case constant value for our own clocks.
 299                  * We don't have to do any lookup to find ourselves.
 300                  */
 301                 err = posix_cpu_clock_get_task(current, which_clock, tp);
 302         } else {
 303                 /*
 304                  * Find the given PID, and validate that the caller
 305                  * should be able to see it.
 306                  */
 307                 struct task_struct *p;
 308                 rcu_read_lock();
 309                 p = find_task_by_vpid(pid);
 310                 if (p)
 311                         err = posix_cpu_clock_get_task(p, which_clock, tp);
 312                 rcu_read_unlock();
 313         }
 314
 315         return err;
 316 }
 317
 318 /*
 319  * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
 320  * This is called from sys_timer_create() and do_cpu_nanosleep() with the
 321  * new timer already all-zeros initialized.
 322  */
 323 static int posix_cpu_timer_create(struct k_itimer *new_timer)
 324 {
 325         int ret = 0;
 326         const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
 327         struct task_struct *p;
 328
 329         if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
 330                 return -EINVAL;
 331
 332         new_timer->kclock = &clock_posix_cpu;
 333
 334         INIT_LIST_HEAD(&new_timer->it.cpu.entry);
 335
 336         rcu_read_lock();
 337         if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
 338                 if (pid == 0) {
 339                         p = current;
 340                 } else {
 341                         p = find_task_by_vpid(pid);
 342                         if (p && !same_thread_group(p, current))
 343                                 p = NULL;
 344                 }
 345         } else {
 346                 if (pid == 0) {
 347                         p = current->group_leader;
 348                 } else {
 349                         p = find_task_by_vpid(pid);
 350                         if (p && !has_group_leader_pid(p))
 351                                 p = NULL;
 352                 }
 353         }
 354         new_timer->it.cpu.task = p;
 355         if (p) {
 356                 get_task_struct(p);
 357         } else {
 358                 ret = -EINVAL;
 359         }
 360         rcu_read_unlock();
 361
 362         return ret;
 363 }
 364
 365 /*
 366  * Clean up a CPU-clock timer that is about to be destroyed.
 367  * This is called from timer deletion with the timer already locked.
 368  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 369  * and try again.  (This happens when the timer is in the middle of firing.)
 370  */
 371 static int posix_cpu_timer_del(struct k_itimer *timer)
 372 {
 373         int ret = 0;
 374         unsigned long flags;
 375         struct sighand_struct *sighand;
 376         struct task_struct *p = timer->it.cpu.task;
 377
 378         WARN_ON_ONCE(p == NULL);
 379
 380         /*
 381          * Protect against sighand release/switch in exit/exec and process/
 382          * thread timer list entry concurrent read/writes.
 383          */
 384         sighand = lock_task_sighand(p, &flags);
 385         if (unlikely(sighand == NULL)) {
 386                 /*
 387                  * We raced with the reaping of the task.
 388                  * The deletion should have cleared us off the list.
 389                  */
 390                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
 391         } else {
 392                 if (timer->it.cpu.firing)
 393                         ret = TIMER_RETRY;
 394                 else
 395                         list_del(&timer->it.cpu.entry);
 396
 397                 unlock_task_sighand(p, &flags);
 398         }
 399
 400         if (!ret)
 401                 put_task_struct(p);
 402
 403         return ret;
 404 }
 405
 406 static void cleanup_timers_list(struct list_head *head)
 407 {
 408         struct cpu_timer_list *timer, *next;
 409
 410         list_for_each_entry_safe(timer, next, head, entry)
 411                 list_del_init(&timer->entry);
 412 }
 413
 414 /*
 415  * Clean out CPU timers still ticking when a thread exited.  The task
 416  * pointer is cleared, and the expiry time is replaced with the residual
 417  * time for later timer_gettime calls to return.
 418  * This must be called with the siglock held.
 419  */
 420 static void cleanup_timers(struct list_head *head)
 421 {
 422         cleanup_timers_list(head);
 423         cleanup_timers_list(++head);
 424         cleanup_timers_list(++head);
 425 }
 426
 427 /*
 428  * These are both called with the siglock held, when the current thread
 429  * is being reaped.  When the final (leader) thread in the group is reaped,
 430  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
 431  */
 432 void posix_cpu_timers_exit(struct task_struct *tsk)
 433 {
 434         cleanup_timers(tsk->cpu_timers);
 435 }
 436 void posix_cpu_timers_exit_group(struct task_struct *tsk)
 437 {
 438         cleanup_timers(tsk->signal->cpu_timers);
 439 }
 440
 441 static inline int expires_gt(u64 expires, u64 new_exp)
 442 {
 443         return expires == 0 || expires > new_exp;
 444 }
 445
 446 /*
 447  * Insert the timer on the appropriate list before any timers that
 448  * expire later.  This must be called with the sighand lock held.
 449  */
 450 static void arm_timer(struct k_itimer *timer)
 451 {
 452         struct task_struct *p = timer->it.cpu.task;
 453         struct list_head *head, *listpos;
 454         struct task_cputime *cputime_expires;
 455         struct cpu_timer_list *const nt = &timer->it.cpu;
 456         struct cpu_timer_list *next;
 457
 458         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 459                 head = p->cpu_timers;
 460                 cputime_expires = &p->cputime_expires;
 461         } else {
 462                 head = p->signal->cpu_timers;
 463                 cputime_expires = &p->signal->cputime_expires;
 464         }
 465         head += CPUCLOCK_WHICH(timer->it_clock);
 466
 467         listpos = head;
 468         list_for_each_entry(next, head, entry) {
 469                 if (nt->expires < next->expires)
 470                         break;
 471                 listpos = &next->entry;
 472         }
 473         list_add(&nt->entry, listpos);
 474
 475         if (listpos == head) {
 476                 u64 exp = nt->expires;
 477
 478                 /*
 479                  * We are the new earliest-expiring POSIX 1.b timer, hence
 480                  * need to update expiration cache. Take into account that
 481                  * for process timers we share expiration cache with itimers
 482                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
 483                  */
 484
 485                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
 486                 case CPUCLOCK_PROF:
 487                         if (expires_gt(cputime_expires->prof_exp, exp))
 488                                 cputime_expires->prof_exp = exp;
 489                         break;
 490                 case CPUCLOCK_VIRT:
 491                         if (expires_gt(cputime_expires->virt_exp, exp))
 492                                 cputime_expires->virt_exp = exp;
 493                         break;
 494                 case CPUCLOCK_SCHED:
 495                         if (expires_gt(cputime_expires->sched_exp, exp))
 496                                 cputime_expires->sched_exp = exp;
 497                         break;
 498                 }
 499                 if (CPUCLOCK_PERTHREAD(timer->it_clock))
 500                         tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
 501                 else
 502                         tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
 503         }
 504 }
 505
 506 /*
 507  * The timer is locked, fire it and arrange for its reload.
 508  */
 509 static void cpu_timer_fire(struct k_itimer *timer)
 510 {
 511         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
 512                 /*
 513                  * User don't want any signal.
 514                  */
 515                 timer->it.cpu.expires = 0;
 516         } else if (unlikely(timer->sigq == NULL)) {
 517                 /*
 518                  * This a special case for clock_nanosleep,
 519                  * not a normal timer from sys_timer_create.
 520                  */
 521                 wake_up_process(timer->it_process);
 522                 timer->it.cpu.expires = 0;
 523         } else if (timer->it.cpu.incr == 0) {
 524                 /*
 525                  * One-shot timer.  Clear it as soon as it's fired.
 526                  */
 527                 posix_timer_event(timer, 0);
 528                 timer->it.cpu.expires = 0;
 529         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
 530                 /*
 531                  * The signal did not get queued because the signal
 532                  * was ignored, so we won't get any callback to
 533                  * reload the timer.  But we need to keep it
 534                  * ticking in case the signal is deliverable next time.
 535                  */
 536                 posix_cpu_timer_rearm(timer);
 537                 ++timer->it_requeue_pending;
 538         }
 539 }
 540
 541 /*
 542  * Sample a process (thread group) timer for the given group_leader task.
 543  * Must be called with task sighand lock held for safe while_each_thread()
 544  * traversal.
 545  */
 546 static int cpu_timer_sample_group(const clockid_t which_clock,
 547                                   struct task_struct *p, u64 *sample)
 548 {
 549         struct task_cputime cputime;
 550
 551         thread_group_cputimer(p, &cputime);
 552         switch (CPUCLOCK_WHICH(which_clock)) {
 553         default:
 554                 return -EINVAL;
 555         case CPUCLOCK_PROF:
 556                 *sample = cputime.utime + cputime.stime;
 557                 break;
 558         case CPUCLOCK_VIRT:
 559                 *sample = cputime.utime;
 560                 break;
 561         case CPUCLOCK_SCHED:
 562                 *sample = cputime.sum_exec_runtime;
 563                 break;
 564         }
 565         return 0;
 566 }
 567
 568 /*
 569  * Guts of sys_timer_settime for CPU timers.
 570  * This is called with the timer locked and interrupts disabled.
 571  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 572  * and try again.  (This happens when the timer is in the middle of firing.)
 573  */
 574 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 575                                struct itimerspec64 *new, struct itimerspec64 *old)
 576 {
 577         unsigned long flags;
 578         struct sighand_struct *sighand;
 579         struct task_struct *p = timer->it.cpu.task;
 580         u64 old_expires, new_expires, old_incr, val;
 581         int ret;
 582
 583         WARN_ON_ONCE(p == NULL);
 584
 585         /*
 586          * Use the to_ktime conversion because that clamps the maximum
 587          * value to KTIME_MAX and avoid multiplication overflows.
 588          */
 589         new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
 590
 591         /*
 592          * Protect against sighand release/switch in exit/exec and p->cpu_timers
 593          * and p->signal->cpu_timers read/write in arm_timer()
 594          */
 595         sighand = lock_task_sighand(p, &flags);
 596         /*
 597          * If p has just been reaped, we can no
 598          * longer get any information about it at all.
 599          */
 600         if (unlikely(sighand == NULL)) {
 601                 return -ESRCH;
 602         }
 603
 604         /*
 605          * Disarm any old timer after extracting its expiry time.
 606          */
 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         timer->it_interval = ns_to_ktime(timer->it.cpu.incr);
 689
 690         /*
 691          * This acts as a modification timestamp for the timer,
 692          * so any automatic reload attempt will punt on seeing
 693          * that we have reset the timer manually.
 694          */
 695         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
 696                 ~REQUEUE_PENDING;
 697         timer->it_overrun_last = 0;
 698         timer->it_overrun = -1;
 699
 700         if (new_expires != 0 && !(val < new_expires)) {
 701                 /*
 702                  * The designated time already passed, so we notify
 703                  * immediately, even if the thread never runs to
 704                  * accumulate more time on this clock.
 705                  */
 706                 cpu_timer_fire(timer);
 707         }
 708
 709         ret = 0;
 710  out:
 711         if (old)
 712                 old->it_interval = ns_to_timespec64(old_incr);
 713
 714         return ret;
 715 }
 716
 717 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
 718 {
 719         u64 now;
 720         struct task_struct *p = timer->it.cpu.task;
 721
 722         WARN_ON_ONCE(p == NULL);
 723
 724         /*
 725          * Easy part: convert the reload time.
 726          */
 727         itp->it_interval = ns_to_timespec64(timer->it.cpu.incr);
 728
 729         if (!timer->it.cpu.expires)
 730                 return;
 731
 732         /*
 733          * Sample the clock to take the difference with the expiry time.
 734          */
 735         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 736                 cpu_clock_sample(timer->it_clock, p, &now);
 737         } else {
 738                 struct sighand_struct *sighand;
 739                 unsigned long flags;
 740
 741                 /*
 742                  * Protect against sighand release/switch in exit/exec and
 743                  * also make timer sampling safe if it ends up calling
 744                  * thread_group_cputime().
 745                  */
 746                 sighand = lock_task_sighand(p, &flags);
 747                 if (unlikely(sighand == NULL)) {
 748                         /*
 749                          * The process has been reaped.
 750                          * We can't even collect a sample any more.
 751                          * Call the timer disarmed, nothing else to do.
 752                          */
 753                         timer->it.cpu.expires = 0;
 754                         return;
 755                 } else {
 756                         cpu_timer_sample_group(timer->it_clock, p, &now);
 757                         unlock_task_sighand(p, &flags);
 758                 }
 759         }
 760
 761         if (now < timer->it.cpu.expires) {
 762                 itp->it_value = ns_to_timespec64(timer->it.cpu.expires - now);
 763         } else {
 764                 /*
 765                  * The timer should have expired already, but the firing
 766                  * hasn't taken place yet.  Say it's just about to expire.
 767                  */
 768                 itp->it_value.tv_nsec = 1;
 769                 itp->it_value.tv_sec = 0;
 770         }
 771 }
 772
 773 static unsigned long long
 774 check_timers_list(struct list_head *timers,
 775                   struct list_head *firing,
 776                   unsigned long long curr)
 777 {
 778         int maxfire = 20;
 779
 780         while (!list_empty(timers)) {
 781                 struct cpu_timer_list *t;
 782
 783                 t = list_first_entry(timers, struct cpu_timer_list, entry);
 784
 785                 if (!--maxfire || curr < t->expires)
 786                         return t->expires;
 787
 788                 t->firing = 1;
 789                 list_move_tail(&t->entry, firing);
 790         }
 791
 792         return 0;
 793 }
 794
 795 static inline void check_dl_overrun(struct task_struct *tsk)
 796 {
 797         if (tsk->dl.dl_overrun) {
 798                 tsk->dl.dl_overrun = 0;
 799                 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 800         }
 801 }
 802
 803 /*
 804  * Check for any per-thread CPU timers that have fired and move them off
 805  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
 806  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
 807  */
 808 static void check_thread_timers(struct task_struct *tsk,
 809                                 struct list_head *firing)
 810 {
 811         struct list_head *timers = tsk->cpu_timers;
 812         struct task_cputime *tsk_expires = &tsk->cputime_expires;
 813         u64 expires;
 814         unsigned long soft;
 815
 816         if (dl_task(tsk))
 817                 check_dl_overrun(tsk);
 818
 819         /*
 820          * If cputime_expires is zero, then there are no active
 821          * per thread CPU timers.
 822          */
 823         if (task_cputime_zero(&tsk->cputime_expires))
 824                 return;
 825
 826         expires = check_timers_list(timers, firing, prof_ticks(tsk));
 827         tsk_expires->prof_exp = expires;
 828
 829         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
 830         tsk_expires->virt_exp = expires;
 831
 832         tsk_expires->sched_exp = check_timers_list(++timers, firing,
 833                                                    tsk->se.sum_exec_runtime);
 834
 835         /*
 836          * Check for the special case thread timers.
 837          */
 838         soft = task_rlimit(tsk, RLIMIT_RTTIME);
 839         if (soft != RLIM_INFINITY) {
 840                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
 841
 842                 if (hard != RLIM_INFINITY &&
 843                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
 844                         /*
 845                          * At the hard limit, we just die.
 846                          * No need to calculate anything else now.
 847                          */
 848                         if (print_fatal_signals) {
 849                                 pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
 850                                         tsk->comm, task_pid_nr(tsk));
 851                         }
 852                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 853                         return;
 854                 }
 855                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
 856                         /*
 857                          * At the soft limit, send a SIGXCPU every second.
 858                          */
 859                         if (soft < hard) {
 860                                 soft += USEC_PER_SEC;
 861                                 tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur =
 862                                         soft;
 863                         }
 864                         if (print_fatal_signals) {
 865                                 pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
 866                                         tsk->comm, task_pid_nr(tsk));
 867                         }
 868                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 869                 }
 870         }
 871         if (task_cputime_zero(tsk_expires))
 872                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 873 }
 874
 875 static inline void stop_process_timers(struct signal_struct *sig)
 876 {
 877         struct thread_group_cputimer *cputimer = &sig->cputimer;
 878
 879         /* Turn off cputimer->running. This is done without locking. */
 880         WRITE_ONCE(cputimer->running, false);
 881         tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
 882 }
 883
 884 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 885                              u64 *expires, u64 cur_time, int signo)
 886 {
 887         if (!it->expires)
 888                 return;
 889
 890         if (cur_time >= it->expires) {
 891                 if (it->incr)
 892                         it->expires += it->incr;
 893                 else
 894                         it->expires = 0;
 895
 896                 trace_itimer_expire(signo == SIGPROF ?
 897                                     ITIMER_PROF : ITIMER_VIRTUAL,
 898                                     task_tgid(tsk), cur_time);
 899                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
 900         }
 901
 902         if (it->expires && (!*expires || it->expires < *expires))
 903                 *expires = it->expires;
 904 }
 905
 906 /*
 907  * Check for any per-thread CPU timers that have fired and move them
 908  * off the tsk->*_timers list onto the firing list.  Per-thread timers
 909  * have already been taken off.
 910  */
 911 static void check_process_timers(struct task_struct *tsk,
 912                                  struct list_head *firing)
 913 {
 914         struct signal_struct *const sig = tsk->signal;
 915         u64 utime, ptime, virt_expires, prof_expires;
 916         u64 sum_sched_runtime, sched_expires;
 917         struct list_head *timers = sig->cpu_timers;
 918         struct task_cputime cputime;
 919         unsigned long soft;
 920
 921         /*
 922          * If cputimer is not running, then there are no active
 923          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
 924          */
 925         if (!READ_ONCE(tsk->signal->cputimer.running))
 926                 return;
 927
 928         /*
 929          * Signify that a thread is checking for process timers.
 930          * Write access to this field is protected by the sighand lock.
 931          */
 932         sig->cputimer.checking_timer = true;
 933
 934         /*
 935          * Collect the current process totals.
 936          */
 937         thread_group_cputimer(tsk, &cputime);
 938         utime = cputime.utime;
 939         ptime = utime + cputime.stime;
 940         sum_sched_runtime = cputime.sum_exec_runtime;
 941
 942         prof_expires = check_timers_list(timers, firing, ptime);
 943         virt_expires = check_timers_list(++timers, firing, utime);
 944         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
 945
 946         /*
 947          * Check for the special case process timers.
 948          */
 949         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
 950                          SIGPROF);
 951         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
 952                          SIGVTALRM);
 953         soft = task_rlimit(tsk, RLIMIT_CPU);
 954         if (soft != RLIM_INFINITY) {
 955                 unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
 956                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
 957                 u64 x;
 958                 if (psecs >= hard) {
 959                         /*
 960                          * At the hard limit, we just die.
 961                          * No need to calculate anything else now.
 962                          */
 963                         if (print_fatal_signals) {
 964                                 pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
 965                                         tsk->comm, task_pid_nr(tsk));
 966                         }
 967                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 968                         return;
 969                 }
 970                 if (psecs >= soft) {
 971                         /*
 972                          * At the soft limit, send a SIGXCPU every second.
 973                          */
 974                         if (print_fatal_signals) {
 975                                 pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
 976                                         tsk->comm, task_pid_nr(tsk));
 977                         }
 978                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 979                         if (soft < hard) {
 980                                 soft++;
 981                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
 982                         }
 983                 }
 984                 x = soft * NSEC_PER_SEC;
 985                 if (!prof_expires || x < prof_expires)
 986                         prof_expires = x;
 987         }
 988
 989         sig->cputime_expires.prof_exp = prof_expires;
 990         sig->cputime_expires.virt_exp = virt_expires;
 991         sig->cputime_expires.sched_exp = sched_expires;
 992         if (task_cputime_zero(&sig->cputime_expires))
 993                 stop_process_timers(sig);
 994
 995         sig->cputimer.checking_timer = false;
 996 }
 997
 998 /*
 999  * This is called from the signal code (via posixtimer_rearm)
1000  * when the last timer signal was delivered and we have to reload the timer.
1001  */
1002 static void posix_cpu_timer_rearm(struct k_itimer *timer)
1003 {
1004         struct sighand_struct *sighand;
1005         unsigned long flags;
1006         struct task_struct *p = timer->it.cpu.task;
1007         u64 now;
1008
1009         WARN_ON_ONCE(p == NULL);
1010
1011         /*
1012          * Fetch the current sample and update the timer's expiry time.
1013          */
1014         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1015                 cpu_clock_sample(timer->it_clock, p, &now);
1016                 bump_cpu_timer(timer, now);
1017                 if (unlikely(p->exit_state))
1018                         return;
1019
1020                 /* Protect timer list r/w in arm_timer() */
1021                 sighand = lock_task_sighand(p, &flags);
1022                 if (!sighand)
1023                         return;
1024         } else {
1025                 /*
1026                  * Protect arm_timer() and timer sampling in case of call to
1027                  * thread_group_cputime().
1028                  */
1029                 sighand = lock_task_sighand(p, &flags);
1030                 if (unlikely(sighand == NULL)) {
1031                         /*
1032                          * The process has been reaped.
1033                          * We can't even collect a sample any more.
1034                          */
1035                         timer->it.cpu.expires = 0;
1036                         return;
1037                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1038                         /* If the process is dying, no need to rearm */
1039                         goto unlock;
1040                 }
1041                 cpu_timer_sample_group(timer->it_clock, p, &now);
1042                 bump_cpu_timer(timer, now);
1043                 /* Leave the sighand locked for the call below.  */
1044         }
1045
1046         /*
1047          * Now re-arm for the new expiry time.
1048          */
1049         arm_timer(timer);
1050 unlock:
1051         unlock_task_sighand(p, &flags);
1052 }
1053
1054 /**
1055  * task_cputime_expired - Compare two task_cputime entities.
1056  *
1057  * @sample:     The task_cputime structure to be checked for expiration.
1058  * @expires:    Expiration times, against which @sample will be checked.
1059  *
1060  * Checks @sample against @expires to see if any field of @sample has expired.
1061  * Returns true if any field of the former is greater than the corresponding
1062  * field of the latter if the latter field is set.  Otherwise returns false.
1063  */
1064 static inline int task_cputime_expired(const struct task_cputime *sample,
1065                                         const struct task_cputime *expires)
1066 {
1067         if (expires->utime && sample->utime >= expires->utime)
1068                 return 1;
1069         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1070                 return 1;
1071         if (expires->sum_exec_runtime != 0 &&
1072             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1073                 return 1;
1074         return 0;
1075 }
1076
1077 /**
1078  * fastpath_timer_check - POSIX CPU timers fast path.
1079  *
1080  * @tsk:        The task (thread) being checked.
1081  *
1082  * Check the task and thread group timers.  If both are zero (there are no
1083  * timers set) return false.  Otherwise snapshot the task and thread group
1084  * timers and compare them with the corresponding expiration times.  Return
1085  * true if a timer has expired, else return false.
1086  */
1087 static inline int fastpath_timer_check(struct task_struct *tsk)
1088 {
1089         struct signal_struct *sig;
1090
1091         if (!task_cputime_zero(&tsk->cputime_expires)) {
1092                 struct task_cputime task_sample;
1093
1094                 task_cputime(tsk, &task_sample.utime, &task_sample.stime);
1095                 task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
1096                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1097                         return 1;
1098         }
1099
1100         sig = tsk->signal;
1101         /*
1102          * Check if thread group timers expired when the cputimer is
1103          * running and no other thread in the group is already checking
1104          * for thread group cputimers. These fields are read without the
1105          * sighand lock. However, this is fine because this is meant to
1106          * be a fastpath heuristic to determine whether we should try to
1107          * acquire the sighand lock to check/handle timers.
1108          *
1109          * In the worst case scenario, if 'running' or 'checking_timer' gets
1110          * set but the current thread doesn't see the change yet, we'll wait
1111          * until the next thread in the group gets a scheduler interrupt to
1112          * handle the timer. This isn't an issue in practice because these
1113          * types of delays with signals actually getting sent are expected.
1114          */
1115         if (READ_ONCE(sig->cputimer.running) &&
1116             !READ_ONCE(sig->cputimer.checking_timer)) {
1117                 struct task_cputime group_sample;
1118
1119                 sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
1120
1121                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1122                         return 1;
1123         }
1124
1125         if (dl_task(tsk) && tsk->dl.dl_overrun)
1126                 return 1;
1127
1128         return 0;
1129 }
1130
1131 /*
1132  * This is called from the timer interrupt handler.  The irq handler has
1133  * already updated our counts.  We need to check if any timers fire now.
1134  * Interrupts are disabled.
1135  */
1136 void run_posix_cpu_timers(struct task_struct *tsk)
1137 {
1138         LIST_HEAD(firing);
1139         struct k_itimer *timer, *next;
1140         unsigned long flags;
1141
1142         lockdep_assert_irqs_disabled();
1143
1144         /*
1145          * The fast path checks that there are no expired thread or thread
1146          * group timers.  If that's so, just return.
1147          */
1148         if (!fastpath_timer_check(tsk))
1149                 return;
1150
1151         if (!lock_task_sighand(tsk, &flags))
1152                 return;
1153         /*
1154          * Here we take off tsk->signal->cpu_timers[N] and
1155          * tsk->cpu_timers[N] all the timers that are firing, and
1156          * put them on the firing list.
1157          */
1158         check_thread_timers(tsk, &firing);
1159
1160         check_process_timers(tsk, &firing);
1161
1162         /*
1163          * We must release these locks before taking any timer's lock.
1164          * There is a potential race with timer deletion here, as the
1165          * siglock now protects our private firing list.  We have set
1166          * the firing flag in each timer, so that a deletion attempt
1167          * that gets the timer lock before we do will give it up and
1168          * spin until we've taken care of that timer below.
1169          */
1170         unlock_task_sighand(tsk, &flags);
1171
1172         /*
1173          * Now that all the timers on our list have the firing flag,
1174          * no one will touch their list entries but us.  We'll take
1175          * each timer's lock before clearing its firing flag, so no
1176          * timer call will interfere.
1177          */
1178         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1179                 int cpu_firing;
1180
1181                 spin_lock(&timer->it_lock);
1182                 list_del_init(&timer->it.cpu.entry);
1183                 cpu_firing = timer->it.cpu.firing;
1184                 timer->it.cpu.firing = 0;
1185                 /*
1186                  * The firing flag is -1 if we collided with a reset
1187                  * of the timer, which already reported this
1188                  * almost-firing as an overrun.  So don't generate an event.
1189                  */
1190                 if (likely(cpu_firing >= 0))
1191                         cpu_timer_fire(timer);
1192                 spin_unlock(&timer->it_lock);
1193         }
1194 }
1195
1196 /*
1197  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1198  * The tsk->sighand->siglock must be held by the caller.
1199  */
1200 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1201                            u64 *newval, u64 *oldval)
1202 {
1203         u64 now;
1204         int ret;
1205
1206         WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
1207         ret = cpu_timer_sample_group(clock_idx, tsk, &now);
1208
1209         if (oldval && ret != -EINVAL) {
1210                 /*
1211                  * We are setting itimer. The *oldval is absolute and we update
1212                  * it to be relative, *newval argument is relative and we update
1213                  * it to be absolute.
1214                  */
1215                 if (*oldval) {
1216                         if (*oldval <= now) {
1217                                 /* Just about to fire. */
1218                                 *oldval = TICK_NSEC;
1219                         } else {
1220                                 *oldval -= now;
1221                         }
1222                 }
1223
1224                 if (!*newval)
1225                         return;
1226                 *newval += now;
1227         }
1228
1229         /*
1230          * Update expiration cache if we are the earliest timer, or eventually
1231          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1232          */
1233         switch (clock_idx) {
1234         case CPUCLOCK_PROF:
1235                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1236                         tsk->signal->cputime_expires.prof_exp = *newval;
1237                 break;
1238         case CPUCLOCK_VIRT:
1239                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1240                         tsk->signal->cputime_expires.virt_exp = *newval;
1241                 break;
1242         }
1243
1244         tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1245 }
1246
1247 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1248                             const struct timespec64 *rqtp)
1249 {
1250         struct itimerspec64 it;
1251         struct k_itimer timer;
1252         u64 expires;
1253         int error;
1254
1255         /*
1256          * Set up a temporary timer and then wait for it to go off.
1257          */
1258         memset(&timer, 0, sizeof timer);
1259         spin_lock_init(&timer.it_lock);
1260         timer.it_clock = which_clock;
1261         timer.it_overrun = -1;
1262         error = posix_cpu_timer_create(&timer);
1263         timer.it_process = current;
1264         if (!error) {
1265                 static struct itimerspec64 zero_it;
1266                 struct restart_block *restart;
1267
1268                 memset(&it, 0, sizeof(it));
1269                 it.it_value = *rqtp;
1270
1271                 spin_lock_irq(&timer.it_lock);
1272                 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1273                 if (error) {
1274                         spin_unlock_irq(&timer.it_lock);
1275                         return error;
1276                 }
1277
1278                 while (!signal_pending(current)) {
1279                         if (timer.it.cpu.expires == 0) {
1280                                 /*
1281                                  * Our timer fired and was reset, below
1282                                  * deletion can not fail.
1283                                  */
1284                                 posix_cpu_timer_del(&timer);
1285                                 spin_unlock_irq(&timer.it_lock);
1286                                 return 0;
1287                         }
1288
1289                         /*
1290                          * Block until cpu_timer_fire (or a signal) wakes us.
1291                          */
1292                         __set_current_state(TASK_INTERRUPTIBLE);
1293                         spin_unlock_irq(&timer.it_lock);
1294                         schedule();
1295                         spin_lock_irq(&timer.it_lock);
1296                 }
1297
1298                 /*
1299                  * We were interrupted by a signal.
1300                  */
1301                 expires = timer.it.cpu.expires;
1302                 error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1303                 if (!error) {
1304                         /*
1305                          * Timer is now unarmed, deletion can not fail.
1306                          */
1307                         posix_cpu_timer_del(&timer);
1308                 }
1309                 spin_unlock_irq(&timer.it_lock);
1310
1311                 while (error == TIMER_RETRY) {
1312                         /*
1313                          * We need to handle case when timer was or is in the
1314                          * middle of firing. In other cases we already freed
1315                          * resources.
1316                          */
1317                         spin_lock_irq(&timer.it_lock);
1318                         error = posix_cpu_timer_del(&timer);
1319                         spin_unlock_irq(&timer.it_lock);
1320                 }
1321
1322                 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1323                         /*
1324                          * It actually did fire already.
1325                          */
1326                         return 0;
1327                 }
1328
1329                 error = -ERESTART_RESTARTBLOCK;
1330                 /*
1331                  * Report back to the user the time still remaining.
1332                  */
1333                 restart = &current->restart_block;
1334                 restart->nanosleep.expires = expires;
1335                 if (restart->nanosleep.type != TT_NONE)
1336                         error = nanosleep_copyout(restart, &it.it_value);
1337         }
1338
1339         return error;
1340 }
1341
1342 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1343
1344 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1345                             const struct timespec64 *rqtp)
1346 {
1347         struct restart_block *restart_block = &current->restart_block;
1348         int error;
1349
1350         /*
1351          * Diagnose required errors first.
1352          */
1353         if (CPUCLOCK_PERTHREAD(which_clock) &&
1354             (CPUCLOCK_PID(which_clock) == 0 ||
1355              CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1356                 return -EINVAL;
1357
1358         error = do_cpu_nanosleep(which_clock, flags, rqtp);
1359
1360         if (error == -ERESTART_RESTARTBLOCK) {
1361
1362                 if (flags & TIMER_ABSTIME)
1363                         return -ERESTARTNOHAND;
1364
1365                 restart_block->fn = posix_cpu_nsleep_restart;
1366                 restart_block->nanosleep.clockid = which_clock;
1367         }
1368         return error;
1369 }
1370
1371 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1372 {
1373         clockid_t which_clock = restart_block->nanosleep.clockid;
1374         struct timespec64 t;
1375
1376         t = ns_to_timespec64(restart_block->nanosleep.expires);
1377
1378         return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1379 }
1380
1381 #define PROCESS_CLOCK   make_process_cpuclock(0, CPUCLOCK_SCHED)
1382 #define THREAD_CLOCK    make_thread_cpuclock(0, CPUCLOCK_SCHED)
1383
1384 static int process_cpu_clock_getres(const clockid_t which_clock,
1385                                     struct timespec64 *tp)
1386 {
1387         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1388 }
1389 static int process_cpu_clock_get(const clockid_t which_clock,
1390                                  struct timespec64 *tp)
1391 {
1392         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1393 }
1394 static int process_cpu_timer_create(struct k_itimer *timer)
1395 {
1396         timer->it_clock = PROCESS_CLOCK;
1397         return posix_cpu_timer_create(timer);
1398 }
1399 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1400                               const struct timespec64 *rqtp)
1401 {
1402         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1403 }
1404 static int thread_cpu_clock_getres(const clockid_t which_clock,
1405                                    struct timespec64 *tp)
1406 {
1407         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1408 }
1409 static int thread_cpu_clock_get(const clockid_t which_clock,
1410                                 struct timespec64 *tp)
1411 {
1412         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1413 }
1414 static int thread_cpu_timer_create(struct k_itimer *timer)
1415 {
1416         timer->it_clock = THREAD_CLOCK;
1417         return posix_cpu_timer_create(timer);
1418 }
1419
1420 const struct k_clock clock_posix_cpu = {
1421         .clock_getres   = posix_cpu_clock_getres,
1422         .clock_set      = posix_cpu_clock_set,
1423         .clock_get      = posix_cpu_clock_get,
1424         .timer_create   = posix_cpu_timer_create,
1425         .nsleep         = posix_cpu_nsleep,
1426         .timer_set      = posix_cpu_timer_set,
1427         .timer_del      = posix_cpu_timer_del,
1428         .timer_get      = posix_cpu_timer_get,
1429         .timer_rearm    = posix_cpu_timer_rearm,
1430 };
1431
1432 const struct k_clock clock_process = {
1433         .clock_getres   = process_cpu_clock_getres,
1434         .clock_get      = process_cpu_clock_get,
1435         .timer_create   = process_cpu_timer_create,
1436         .nsleep         = process_cpu_nsleep,
1437 };
1438
1439 const struct k_clock clock_thread = {
1440         .clock_getres   = thread_cpu_clock_getres,
1441         .clock_get      = thread_cpu_clock_get,
1442         .timer_create   = thread_cpu_timer_create,
1443 };