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         if (WARN_ON_ONCE(!p))
 379                 return -EINVAL;
 380
 381         /*
 382          * Protect against sighand release/switch in exit/exec and process/
 383          * thread timer list entry concurrent read/writes.
 384          */
 385         sighand = lock_task_sighand(p, &flags);
 386         if (unlikely(sighand == NULL)) {
 387                 /*
 388                  * We raced with the reaping of the task.
 389                  * The deletion should have cleared us off the list.
 390                  */
 391                 WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
 392         } else {
 393                 if (timer->it.cpu.firing)
 394                         ret = TIMER_RETRY;
 395                 else
 396                         list_del(&timer->it.cpu.entry);
 397
 398                 unlock_task_sighand(p, &flags);
 399         }
 400
 401         if (!ret)
 402                 put_task_struct(p);
 403
 404         return ret;
 405 }
 406
 407 static void cleanup_timers_list(struct list_head *head)
 408 {
 409         struct cpu_timer_list *timer, *next;
 410
 411         list_for_each_entry_safe(timer, next, head, entry)
 412                 list_del_init(&timer->entry);
 413 }
 414
 415 /*
 416  * Clean out CPU timers still ticking when a thread exited.  The task
 417  * pointer is cleared, and the expiry time is replaced with the residual
 418  * time for later timer_gettime calls to return.
 419  * This must be called with the siglock held.
 420  */
 421 static void cleanup_timers(struct list_head *head)
 422 {
 423         cleanup_timers_list(head);
 424         cleanup_timers_list(++head);
 425         cleanup_timers_list(++head);
 426 }
 427
 428 /*
 429  * These are both called with the siglock held, when the current thread
 430  * is being reaped.  When the final (leader) thread in the group is reaped,
 431  * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
 432  */
 433 void posix_cpu_timers_exit(struct task_struct *tsk)
 434 {
 435         cleanup_timers(tsk->cpu_timers);
 436 }
 437 void posix_cpu_timers_exit_group(struct task_struct *tsk)
 438 {
 439         cleanup_timers(tsk->signal->cpu_timers);
 440 }
 441
 442 static inline int expires_gt(u64 expires, u64 new_exp)
 443 {
 444         return expires == 0 || expires > new_exp;
 445 }
 446
 447 /*
 448  * Insert the timer on the appropriate list before any timers that
 449  * expire later.  This must be called with the sighand lock held.
 450  */
 451 static void arm_timer(struct k_itimer *timer)
 452 {
 453         struct task_struct *p = timer->it.cpu.task;
 454         struct list_head *head, *listpos;
 455         struct task_cputime *cputime_expires;
 456         struct cpu_timer_list *const nt = &timer->it.cpu;
 457         struct cpu_timer_list *next;
 458
 459         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 460                 head = p->cpu_timers;
 461                 cputime_expires = &p->cputime_expires;
 462         } else {
 463                 head = p->signal->cpu_timers;
 464                 cputime_expires = &p->signal->cputime_expires;
 465         }
 466         head += CPUCLOCK_WHICH(timer->it_clock);
 467
 468         listpos = head;
 469         list_for_each_entry(next, head, entry) {
 470                 if (nt->expires < next->expires)
 471                         break;
 472                 listpos = &next->entry;
 473         }
 474         list_add(&nt->entry, listpos);
 475
 476         if (listpos == head) {
 477                 u64 exp = nt->expires;
 478
 479                 /*
 480                  * We are the new earliest-expiring POSIX 1.b timer, hence
 481                  * need to update expiration cache. Take into account that
 482                  * for process timers we share expiration cache with itimers
 483                  * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
 484                  */
 485
 486                 switch (CPUCLOCK_WHICH(timer->it_clock)) {
 487                 case CPUCLOCK_PROF:
 488                         if (expires_gt(cputime_expires->prof_exp, exp))
 489                                 cputime_expires->prof_exp = exp;
 490                         break;
 491                 case CPUCLOCK_VIRT:
 492                         if (expires_gt(cputime_expires->virt_exp, exp))
 493                                 cputime_expires->virt_exp = exp;
 494                         break;
 495                 case CPUCLOCK_SCHED:
 496                         if (expires_gt(cputime_expires->sched_exp, exp))
 497                                 cputime_expires->sched_exp = exp;
 498                         break;
 499                 }
 500                 if (CPUCLOCK_PERTHREAD(timer->it_clock))
 501                         tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
 502                 else
 503                         tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
 504         }
 505 }
 506
 507 /*
 508  * The timer is locked, fire it and arrange for its reload.
 509  */
 510 static void cpu_timer_fire(struct k_itimer *timer)
 511 {
 512         if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
 513                 /*
 514                  * User don't want any signal.
 515                  */
 516                 timer->it.cpu.expires = 0;
 517         } else if (unlikely(timer->sigq == NULL)) {
 518                 /*
 519                  * This a special case for clock_nanosleep,
 520                  * not a normal timer from sys_timer_create.
 521                  */
 522                 wake_up_process(timer->it_process);
 523                 timer->it.cpu.expires = 0;
 524         } else if (timer->it.cpu.incr == 0) {
 525                 /*
 526                  * One-shot timer.  Clear it as soon as it's fired.
 527                  */
 528                 posix_timer_event(timer, 0);
 529                 timer->it.cpu.expires = 0;
 530         } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
 531                 /*
 532                  * The signal did not get queued because the signal
 533                  * was ignored, so we won't get any callback to
 534                  * reload the timer.  But we need to keep it
 535                  * ticking in case the signal is deliverable next time.
 536                  */
 537                 posix_cpu_timer_rearm(timer);
 538                 ++timer->it_requeue_pending;
 539         }
 540 }
 541
 542 /*
 543  * Sample a process (thread group) timer for the given group_leader task.
 544  * Must be called with task sighand lock held for safe while_each_thread()
 545  * traversal.
 546  */
 547 static int cpu_timer_sample_group(const clockid_t which_clock,
 548                                   struct task_struct *p, u64 *sample)
 549 {
 550         struct task_cputime cputime;
 551
 552         thread_group_cputimer(p, &cputime);
 553         switch (CPUCLOCK_WHICH(which_clock)) {
 554         default:
 555                 return -EINVAL;
 556         case CPUCLOCK_PROF:
 557                 *sample = cputime.utime + cputime.stime;
 558                 break;
 559         case CPUCLOCK_VIRT:
 560                 *sample = cputime.utime;
 561                 break;
 562         case CPUCLOCK_SCHED:
 563                 *sample = cputime.sum_exec_runtime;
 564                 break;
 565         }
 566         return 0;
 567 }
 568
 569 /*
 570  * Guts of sys_timer_settime for CPU timers.
 571  * This is called with the timer locked and interrupts disabled.
 572  * If we return TIMER_RETRY, it's necessary to release the timer's lock
 573  * and try again.  (This happens when the timer is in the middle of firing.)
 574  */
 575 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 576                                struct itimerspec64 *new, struct itimerspec64 *old)
 577 {
 578         unsigned long flags;
 579         struct sighand_struct *sighand;
 580         struct task_struct *p = timer->it.cpu.task;
 581         u64 old_expires, new_expires, old_incr, val;
 582         int ret;
 583
 584         if (WARN_ON_ONCE(!p))
 585                 return -EINVAL;
 586
 587         /*
 588          * Use the to_ktime conversion because that clamps the maximum
 589          * value to KTIME_MAX and avoid multiplication overflows.
 590          */
 591         new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
 592
 593         /*
 594          * Protect against sighand release/switch in exit/exec and p->cpu_timers
 595          * and p->signal->cpu_timers read/write in arm_timer()
 596          */
 597         sighand = lock_task_sighand(p, &flags);
 598         /*
 599          * If p has just been reaped, we can no
 600          * longer get any information about it at all.
 601          */
 602         if (unlikely(sighand == NULL)) {
 603                 return -ESRCH;
 604         }
 605
 606         /*
 607          * Disarm any old timer after extracting its expiry time.
 608          */
 609
 610         ret = 0;
 611         old_incr = timer->it.cpu.incr;
 612         old_expires = timer->it.cpu.expires;
 613         if (unlikely(timer->it.cpu.firing)) {
 614                 timer->it.cpu.firing = -1;
 615                 ret = TIMER_RETRY;
 616         } else
 617                 list_del_init(&timer->it.cpu.entry);
 618
 619         /*
 620          * We need to sample the current value to convert the new
 621          * value from to relative and absolute, and to convert the
 622          * old value from absolute to relative.  To set a process
 623          * timer, we need a sample to balance the thread expiry
 624          * times (in arm_timer).  With an absolute time, we must
 625          * check if it's already passed.  In short, we need a sample.
 626          */
 627         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 628                 cpu_clock_sample(timer->it_clock, p, &val);
 629         } else {
 630                 cpu_timer_sample_group(timer->it_clock, p, &val);
 631         }
 632
 633         if (old) {
 634                 if (old_expires == 0) {
 635                         old->it_value.tv_sec = 0;
 636                         old->it_value.tv_nsec = 0;
 637                 } else {
 638                         /*
 639                          * Update the timer in case it has
 640                          * overrun already.  If it has,
 641                          * we'll report it as having overrun
 642                          * and with the next reloaded timer
 643                          * already ticking, though we are
 644                          * swallowing that pending
 645                          * notification here to install the
 646                          * new setting.
 647                          */
 648                         bump_cpu_timer(timer, val);
 649                         if (val < timer->it.cpu.expires) {
 650                                 old_expires = timer->it.cpu.expires - val;
 651                                 old->it_value = ns_to_timespec64(old_expires);
 652                         } else {
 653                                 old->it_value.tv_nsec = 1;
 654                                 old->it_value.tv_sec = 0;
 655                         }
 656                 }
 657         }
 658
 659         if (unlikely(ret)) {
 660                 /*
 661                  * We are colliding with the timer actually firing.
 662                  * Punt after filling in the timer's old value, and
 663                  * disable this firing since we are already reporting
 664                  * it as an overrun (thanks to bump_cpu_timer above).
 665                  */
 666                 unlock_task_sighand(p, &flags);
 667                 goto out;
 668         }
 669
 670         if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
 671                 new_expires += val;
 672         }
 673
 674         /*
 675          * Install the new expiry time (or zero).
 676          * For a timer with no notification action, we don't actually
 677          * arm the timer (we'll just fake it for timer_gettime).
 678          */
 679         timer->it.cpu.expires = new_expires;
 680         if (new_expires != 0 && val < new_expires) {
 681                 arm_timer(timer);
 682         }
 683
 684         unlock_task_sighand(p, &flags);
 685         /*
 686          * Install the new reload setting, and
 687          * set up the signal and overrun bookkeeping.
 688          */
 689         timer->it.cpu.incr = timespec64_to_ns(&new->it_interval);
 690         timer->it_interval = ns_to_ktime(timer->it.cpu.incr);
 691
 692         /*
 693          * This acts as a modification timestamp for the timer,
 694          * so any automatic reload attempt will punt on seeing
 695          * that we have reset the timer manually.
 696          */
 697         timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
 698                 ~REQUEUE_PENDING;
 699         timer->it_overrun_last = 0;
 700         timer->it_overrun = -1;
 701
 702         if (new_expires != 0 && !(val < new_expires)) {
 703                 /*
 704                  * The designated time already passed, so we notify
 705                  * immediately, even if the thread never runs to
 706                  * accumulate more time on this clock.
 707                  */
 708                 cpu_timer_fire(timer);
 709         }
 710
 711         ret = 0;
 712  out:
 713         if (old)
 714                 old->it_interval = ns_to_timespec64(old_incr);
 715
 716         return ret;
 717 }
 718
 719 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
 720 {
 721         struct task_struct *p = timer->it.cpu.task;
 722         u64 now;
 723
 724         if (WARN_ON_ONCE(!p))
 725                 return;
 726
 727         /*
 728          * Easy part: convert the reload time.
 729          */
 730         itp->it_interval = ns_to_timespec64(timer->it.cpu.incr);
 731
 732         if (!timer->it.cpu.expires)
 733                 return;
 734
 735         /*
 736          * Sample the clock to take the difference with the expiry time.
 737          */
 738         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 739                 cpu_clock_sample(timer->it_clock, p, &now);
 740         } else {
 741                 struct sighand_struct *sighand;
 742                 unsigned long flags;
 743
 744                 /*
 745                  * Protect against sighand release/switch in exit/exec and
 746                  * also make timer sampling safe if it ends up calling
 747                  * thread_group_cputime().
 748                  */
 749                 sighand = lock_task_sighand(p, &flags);
 750                 if (unlikely(sighand == NULL)) {
 751                         /*
 752                          * The process has been reaped.
 753                          * We can't even collect a sample any more.
 754                          * Call the timer disarmed, nothing else to do.
 755                          */
 756                         timer->it.cpu.expires = 0;
 757                         return;
 758                 } else {
 759                         cpu_timer_sample_group(timer->it_clock, p, &now);
 760                         unlock_task_sighand(p, &flags);
 761                 }
 762         }
 763
 764         if (now < timer->it.cpu.expires) {
 765                 itp->it_value = ns_to_timespec64(timer->it.cpu.expires - now);
 766         } else {
 767                 /*
 768                  * The timer should have expired already, but the firing
 769                  * hasn't taken place yet.  Say it's just about to expire.
 770                  */
 771                 itp->it_value.tv_nsec = 1;
 772                 itp->it_value.tv_sec = 0;
 773         }
 774 }
 775
 776 static unsigned long long
 777 check_timers_list(struct list_head *timers,
 778                   struct list_head *firing,
 779                   unsigned long long curr)
 780 {
 781         int maxfire = 20;
 782
 783         while (!list_empty(timers)) {
 784                 struct cpu_timer_list *t;
 785
 786                 t = list_first_entry(timers, struct cpu_timer_list, entry);
 787
 788                 if (!--maxfire || curr < t->expires)
 789                         return t->expires;
 790
 791                 t->firing = 1;
 792                 list_move_tail(&t->entry, firing);
 793         }
 794
 795         return 0;
 796 }
 797
 798 static inline void check_dl_overrun(struct task_struct *tsk)
 799 {
 800         if (tsk->dl.dl_overrun) {
 801                 tsk->dl.dl_overrun = 0;
 802                 __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 803         }
 804 }
 805
 806 /*
 807  * Check for any per-thread CPU timers that have fired and move them off
 808  * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
 809  * tsk->it_*_expires values to reflect the remaining thread CPU timers.
 810  */
 811 static void check_thread_timers(struct task_struct *tsk,
 812                                 struct list_head *firing)
 813 {
 814         struct list_head *timers = tsk->cpu_timers;
 815         struct task_cputime *tsk_expires = &tsk->cputime_expires;
 816         u64 expires;
 817         unsigned long soft;
 818
 819         if (dl_task(tsk))
 820                 check_dl_overrun(tsk);
 821
 822         /*
 823          * If cputime_expires is zero, then there are no active
 824          * per thread CPU timers.
 825          */
 826         if (task_cputime_zero(&tsk->cputime_expires))
 827                 return;
 828
 829         expires = check_timers_list(timers, firing, prof_ticks(tsk));
 830         tsk_expires->prof_exp = expires;
 831
 832         expires = check_timers_list(++timers, firing, virt_ticks(tsk));
 833         tsk_expires->virt_exp = expires;
 834
 835         tsk_expires->sched_exp = check_timers_list(++timers, firing,
 836                                                    tsk->se.sum_exec_runtime);
 837
 838         /*
 839          * Check for the special case thread timers.
 840          */
 841         soft = task_rlimit(tsk, RLIMIT_RTTIME);
 842         if (soft != RLIM_INFINITY) {
 843                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
 844
 845                 if (hard != RLIM_INFINITY &&
 846                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
 847                         /*
 848                          * At the hard limit, we just die.
 849                          * No need to calculate anything else now.
 850                          */
 851                         if (print_fatal_signals) {
 852                                 pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
 853                                         tsk->comm, task_pid_nr(tsk));
 854                         }
 855                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 856                         return;
 857                 }
 858                 if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
 859                         /*
 860                          * At the soft limit, send a SIGXCPU every second.
 861                          */
 862                         if (soft < hard) {
 863                                 soft += USEC_PER_SEC;
 864                                 tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur =
 865                                         soft;
 866                         }
 867                         if (print_fatal_signals) {
 868                                 pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
 869                                         tsk->comm, task_pid_nr(tsk));
 870                         }
 871                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 872                 }
 873         }
 874         if (task_cputime_zero(tsk_expires))
 875                 tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 876 }
 877
 878 static inline void stop_process_timers(struct signal_struct *sig)
 879 {
 880         struct thread_group_cputimer *cputimer = &sig->cputimer;
 881
 882         /* Turn off cputimer->running. This is done without locking. */
 883         WRITE_ONCE(cputimer->running, false);
 884         tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
 885 }
 886
 887 static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
 888                              u64 *expires, u64 cur_time, int signo)
 889 {
 890         if (!it->expires)
 891                 return;
 892
 893         if (cur_time >= it->expires) {
 894                 if (it->incr)
 895                         it->expires += it->incr;
 896                 else
 897                         it->expires = 0;
 898
 899                 trace_itimer_expire(signo == SIGPROF ?
 900                                     ITIMER_PROF : ITIMER_VIRTUAL,
 901                                     task_tgid(tsk), cur_time);
 902                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
 903         }
 904
 905         if (it->expires && (!*expires || it->expires < *expires))
 906                 *expires = it->expires;
 907 }
 908
 909 /*
 910  * Check for any per-thread CPU timers that have fired and move them
 911  * off the tsk->*_timers list onto the firing list.  Per-thread timers
 912  * have already been taken off.
 913  */
 914 static void check_process_timers(struct task_struct *tsk,
 915                                  struct list_head *firing)
 916 {
 917         struct signal_struct *const sig = tsk->signal;
 918         u64 utime, ptime, virt_expires, prof_expires;
 919         u64 sum_sched_runtime, sched_expires;
 920         struct list_head *timers = sig->cpu_timers;
 921         struct task_cputime cputime;
 922         unsigned long soft;
 923
 924         if (dl_task(tsk))
 925                 check_dl_overrun(tsk);
 926
 927         /*
 928          * If cputimer is not running, then there are no active
 929          * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
 930          */
 931         if (!READ_ONCE(tsk->signal->cputimer.running))
 932                 return;
 933
 934         /*
 935          * Signify that a thread is checking for process timers.
 936          * Write access to this field is protected by the sighand lock.
 937          */
 938         sig->cputimer.checking_timer = true;
 939
 940         /*
 941          * Collect the current process totals.
 942          */
 943         thread_group_cputimer(tsk, &cputime);
 944         utime = cputime.utime;
 945         ptime = utime + cputime.stime;
 946         sum_sched_runtime = cputime.sum_exec_runtime;
 947
 948         prof_expires = check_timers_list(timers, firing, ptime);
 949         virt_expires = check_timers_list(++timers, firing, utime);
 950         sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
 951
 952         /*
 953          * Check for the special case process timers.
 954          */
 955         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
 956                          SIGPROF);
 957         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
 958                          SIGVTALRM);
 959         soft = task_rlimit(tsk, RLIMIT_CPU);
 960         if (soft != RLIM_INFINITY) {
 961                 unsigned long psecs = div_u64(ptime, NSEC_PER_SEC);
 962                 unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
 963                 u64 x;
 964                 if (psecs >= hard) {
 965                         /*
 966                          * At the hard limit, we just die.
 967                          * No need to calculate anything else now.
 968                          */
 969                         if (print_fatal_signals) {
 970                                 pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
 971                                         tsk->comm, task_pid_nr(tsk));
 972                         }
 973                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
 974                         return;
 975                 }
 976                 if (psecs >= soft) {
 977                         /*
 978                          * At the soft limit, send a SIGXCPU every second.
 979                          */
 980                         if (print_fatal_signals) {
 981                                 pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
 982                                         tsk->comm, task_pid_nr(tsk));
 983                         }
 984                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 985                         if (soft < hard) {
 986                                 soft++;
 987                                 sig->rlim[RLIMIT_CPU].rlim_cur = soft;
 988                         }
 989                 }
 990                 x = soft * NSEC_PER_SEC;
 991                 if (!prof_expires || x < prof_expires)
 992                         prof_expires = x;
 993         }
 994
 995         sig->cputime_expires.prof_exp = prof_expires;
 996         sig->cputime_expires.virt_exp = virt_expires;
 997         sig->cputime_expires.sched_exp = sched_expires;
 998         if (task_cputime_zero(&sig->cputime_expires))
 999                 stop_process_timers(sig);
1000
1001         sig->cputimer.checking_timer = false;
1002 }
1003
1004 /*
1005  * This is called from the signal code (via posixtimer_rearm)
1006  * when the last timer signal was delivered and we have to reload the timer.
1007  */
1008 static void posix_cpu_timer_rearm(struct k_itimer *timer)
1009 {
1010         struct task_struct *p = timer->it.cpu.task;
1011         struct sighand_struct *sighand;
1012         unsigned long flags;
1013         u64 now;
1014
1015         if (WARN_ON_ONCE(!p))
1016                 return;
1017
1018         /*
1019          * Fetch the current sample and update the timer's expiry time.
1020          */
1021         if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
1022                 cpu_clock_sample(timer->it_clock, p, &now);
1023                 bump_cpu_timer(timer, now);
1024                 if (unlikely(p->exit_state))
1025                         return;
1026
1027                 /* Protect timer list r/w in arm_timer() */
1028                 sighand = lock_task_sighand(p, &flags);
1029                 if (!sighand)
1030                         return;
1031         } else {
1032                 /*
1033                  * Protect arm_timer() and timer sampling in case of call to
1034                  * thread_group_cputime().
1035                  */
1036                 sighand = lock_task_sighand(p, &flags);
1037                 if (unlikely(sighand == NULL)) {
1038                         /*
1039                          * The process has been reaped.
1040                          * We can't even collect a sample any more.
1041                          */
1042                         timer->it.cpu.expires = 0;
1043                         return;
1044                 } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
1045                         /* If the process is dying, no need to rearm */
1046                         goto unlock;
1047                 }
1048                 cpu_timer_sample_group(timer->it_clock, p, &now);
1049                 bump_cpu_timer(timer, now);
1050                 /* Leave the sighand locked for the call below.  */
1051         }
1052
1053         /*
1054          * Now re-arm for the new expiry time.
1055          */
1056         arm_timer(timer);
1057 unlock:
1058         unlock_task_sighand(p, &flags);
1059 }
1060
1061 /**
1062  * task_cputime_expired - Compare two task_cputime entities.
1063  *
1064  * @sample:     The task_cputime structure to be checked for expiration.
1065  * @expires:    Expiration times, against which @sample will be checked.
1066  *
1067  * Checks @sample against @expires to see if any field of @sample has expired.
1068  * Returns true if any field of the former is greater than the corresponding
1069  * field of the latter if the latter field is set.  Otherwise returns false.
1070  */
1071 static inline int task_cputime_expired(const struct task_cputime *sample,
1072                                         const struct task_cputime *expires)
1073 {
1074         if (expires->utime && sample->utime >= expires->utime)
1075                 return 1;
1076         if (expires->stime && sample->utime + sample->stime >= expires->stime)
1077                 return 1;
1078         if (expires->sum_exec_runtime != 0 &&
1079             sample->sum_exec_runtime >= expires->sum_exec_runtime)
1080                 return 1;
1081         return 0;
1082 }
1083
1084 /**
1085  * fastpath_timer_check - POSIX CPU timers fast path.
1086  *
1087  * @tsk:        The task (thread) being checked.
1088  *
1089  * Check the task and thread group timers.  If both are zero (there are no
1090  * timers set) return false.  Otherwise snapshot the task and thread group
1091  * timers and compare them with the corresponding expiration times.  Return
1092  * true if a timer has expired, else return false.
1093  */
1094 static inline int fastpath_timer_check(struct task_struct *tsk)
1095 {
1096         struct signal_struct *sig;
1097
1098         if (!task_cputime_zero(&tsk->cputime_expires)) {
1099                 struct task_cputime task_sample;
1100
1101                 task_cputime(tsk, &task_sample.utime, &task_sample.stime);
1102                 task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
1103                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
1104                         return 1;
1105         }
1106
1107         sig = tsk->signal;
1108         /*
1109          * Check if thread group timers expired when the cputimer is
1110          * running and no other thread in the group is already checking
1111          * for thread group cputimers. These fields are read without the
1112          * sighand lock. However, this is fine because this is meant to
1113          * be a fastpath heuristic to determine whether we should try to
1114          * acquire the sighand lock to check/handle timers.
1115          *
1116          * In the worst case scenario, if 'running' or 'checking_timer' gets
1117          * set but the current thread doesn't see the change yet, we'll wait
1118          * until the next thread in the group gets a scheduler interrupt to
1119          * handle the timer. This isn't an issue in practice because these
1120          * types of delays with signals actually getting sent are expected.
1121          */
1122         if (READ_ONCE(sig->cputimer.running) &&
1123             !READ_ONCE(sig->cputimer.checking_timer)) {
1124                 struct task_cputime group_sample;
1125
1126                 sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
1127
1128                 if (task_cputime_expired(&group_sample, &sig->cputime_expires))
1129                         return 1;
1130         }
1131
1132         if (dl_task(tsk) && tsk->dl.dl_overrun)
1133                 return 1;
1134
1135         return 0;
1136 }
1137
1138 /*
1139  * This is called from the timer interrupt handler.  The irq handler has
1140  * already updated our counts.  We need to check if any timers fire now.
1141  * Interrupts are disabled.
1142  */
1143 void run_posix_cpu_timers(struct task_struct *tsk)
1144 {
1145         LIST_HEAD(firing);
1146         struct k_itimer *timer, *next;
1147         unsigned long flags;
1148
1149         lockdep_assert_irqs_disabled();
1150
1151         /*
1152          * The fast path checks that there are no expired thread or thread
1153          * group timers.  If that's so, just return.
1154          */
1155         if (!fastpath_timer_check(tsk))
1156                 return;
1157
1158         if (!lock_task_sighand(tsk, &flags))
1159                 return;
1160         /*
1161          * Here we take off tsk->signal->cpu_timers[N] and
1162          * tsk->cpu_timers[N] all the timers that are firing, and
1163          * put them on the firing list.
1164          */
1165         check_thread_timers(tsk, &firing);
1166
1167         check_process_timers(tsk, &firing);
1168
1169         /*
1170          * We must release these locks before taking any timer's lock.
1171          * There is a potential race with timer deletion here, as the
1172          * siglock now protects our private firing list.  We have set
1173          * the firing flag in each timer, so that a deletion attempt
1174          * that gets the timer lock before we do will give it up and
1175          * spin until we've taken care of that timer below.
1176          */
1177         unlock_task_sighand(tsk, &flags);
1178
1179         /*
1180          * Now that all the timers on our list have the firing flag,
1181          * no one will touch their list entries but us.  We'll take
1182          * each timer's lock before clearing its firing flag, so no
1183          * timer call will interfere.
1184          */
1185         list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
1186                 int cpu_firing;
1187
1188                 spin_lock(&timer->it_lock);
1189                 list_del_init(&timer->it.cpu.entry);
1190                 cpu_firing = timer->it.cpu.firing;
1191                 timer->it.cpu.firing = 0;
1192                 /*
1193                  * The firing flag is -1 if we collided with a reset
1194                  * of the timer, which already reported this
1195                  * almost-firing as an overrun.  So don't generate an event.
1196                  */
1197                 if (likely(cpu_firing >= 0))
1198                         cpu_timer_fire(timer);
1199                 spin_unlock(&timer->it_lock);
1200         }
1201 }
1202
1203 /*
1204  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
1205  * The tsk->sighand->siglock must be held by the caller.
1206  */
1207 void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
1208                            u64 *newval, u64 *oldval)
1209 {
1210         u64 now;
1211         int ret;
1212
1213         if (WARN_ON_ONCE(clock_idx >= CPUCLOCK_SCHED))
1214                 return;
1215
1216         ret = cpu_timer_sample_group(clock_idx, tsk, &now);
1217
1218         if (oldval && ret != -EINVAL) {
1219                 /*
1220                  * We are setting itimer. The *oldval is absolute and we update
1221                  * it to be relative, *newval argument is relative and we update
1222                  * it to be absolute.
1223                  */
1224                 if (*oldval) {
1225                         if (*oldval <= now) {
1226                                 /* Just about to fire. */
1227                                 *oldval = TICK_NSEC;
1228                         } else {
1229                                 *oldval -= now;
1230                         }
1231                 }
1232
1233                 if (!*newval)
1234                         return;
1235                 *newval += now;
1236         }
1237
1238         /*
1239          * Update expiration cache if we are the earliest timer, or eventually
1240          * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
1241          */
1242         switch (clock_idx) {
1243         case CPUCLOCK_PROF:
1244                 if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
1245                         tsk->signal->cputime_expires.prof_exp = *newval;
1246                 break;
1247         case CPUCLOCK_VIRT:
1248                 if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
1249                         tsk->signal->cputime_expires.virt_exp = *newval;
1250                 break;
1251         }
1252
1253         tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
1254 }
1255
1256 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
1257                             const struct timespec64 *rqtp)
1258 {
1259         struct itimerspec64 it;
1260         struct k_itimer timer;
1261         u64 expires;
1262         int error;
1263
1264         /*
1265          * Set up a temporary timer and then wait for it to go off.
1266          */
1267         memset(&timer, 0, sizeof timer);
1268         spin_lock_init(&timer.it_lock);
1269         timer.it_clock = which_clock;
1270         timer.it_overrun = -1;
1271         error = posix_cpu_timer_create(&timer);
1272         timer.it_process = current;
1273         if (!error) {
1274                 static struct itimerspec64 zero_it;
1275                 struct restart_block *restart;
1276
1277                 memset(&it, 0, sizeof(it));
1278                 it.it_value = *rqtp;
1279
1280                 spin_lock_irq(&timer.it_lock);
1281                 error = posix_cpu_timer_set(&timer, flags, &it, NULL);
1282                 if (error) {
1283                         spin_unlock_irq(&timer.it_lock);
1284                         return error;
1285                 }
1286
1287                 while (!signal_pending(current)) {
1288                         if (timer.it.cpu.expires == 0) {
1289                                 /*
1290                                  * Our timer fired and was reset, below
1291                                  * deletion can not fail.
1292                                  */
1293                                 posix_cpu_timer_del(&timer);
1294                                 spin_unlock_irq(&timer.it_lock);
1295                                 return 0;
1296                         }
1297
1298                         /*
1299                          * Block until cpu_timer_fire (or a signal) wakes us.
1300                          */
1301                         __set_current_state(TASK_INTERRUPTIBLE);
1302                         spin_unlock_irq(&timer.it_lock);
1303                         schedule();
1304                         spin_lock_irq(&timer.it_lock);
1305                 }
1306
1307                 /*
1308                  * We were interrupted by a signal.
1309                  */
1310                 expires = timer.it.cpu.expires;
1311                 error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
1312                 if (!error) {
1313                         /*
1314                          * Timer is now unarmed, deletion can not fail.
1315                          */
1316                         posix_cpu_timer_del(&timer);
1317                 }
1318                 spin_unlock_irq(&timer.it_lock);
1319
1320                 while (error == TIMER_RETRY) {
1321                         /*
1322                          * We need to handle case when timer was or is in the
1323                          * middle of firing. In other cases we already freed
1324                          * resources.
1325                          */
1326                         spin_lock_irq(&timer.it_lock);
1327                         error = posix_cpu_timer_del(&timer);
1328                         spin_unlock_irq(&timer.it_lock);
1329                 }
1330
1331                 if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
1332                         /*
1333                          * It actually did fire already.
1334                          */
1335                         return 0;
1336                 }
1337
1338                 error = -ERESTART_RESTARTBLOCK;
1339                 /*
1340                  * Report back to the user the time still remaining.
1341                  */
1342                 restart = &current->restart_block;
1343                 restart->nanosleep.expires = expires;
1344                 if (restart->nanosleep.type != TT_NONE)
1345                         error = nanosleep_copyout(restart, &it.it_value);
1346         }
1347
1348         return error;
1349 }
1350
1351 static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
1352
1353 static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
1354                             const struct timespec64 *rqtp)
1355 {
1356         struct restart_block *restart_block = &current->restart_block;
1357         int error;
1358
1359         /*
1360          * Diagnose required errors first.
1361          */
1362         if (CPUCLOCK_PERTHREAD(which_clock) &&
1363             (CPUCLOCK_PID(which_clock) == 0 ||
1364              CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
1365                 return -EINVAL;
1366
1367         error = do_cpu_nanosleep(which_clock, flags, rqtp);
1368
1369         if (error == -ERESTART_RESTARTBLOCK) {
1370
1371                 if (flags & TIMER_ABSTIME)
1372                         return -ERESTARTNOHAND;
1373
1374                 restart_block->nanosleep.clockid = which_clock;
1375                 set_restart_fn(restart_block, posix_cpu_nsleep_restart);
1376         }
1377         return error;
1378 }
1379
1380 static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
1381 {
1382         clockid_t which_clock = restart_block->nanosleep.clockid;
1383         struct timespec64 t;
1384
1385         t = ns_to_timespec64(restart_block->nanosleep.expires);
1386
1387         return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
1388 }
1389
1390 #define PROCESS_CLOCK   make_process_cpuclock(0, CPUCLOCK_SCHED)
1391 #define THREAD_CLOCK    make_thread_cpuclock(0, CPUCLOCK_SCHED)
1392
1393 static int process_cpu_clock_getres(const clockid_t which_clock,
1394                                     struct timespec64 *tp)
1395 {
1396         return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
1397 }
1398 static int process_cpu_clock_get(const clockid_t which_clock,
1399                                  struct timespec64 *tp)
1400 {
1401         return posix_cpu_clock_get(PROCESS_CLOCK, tp);
1402 }
1403 static int process_cpu_timer_create(struct k_itimer *timer)
1404 {
1405         timer->it_clock = PROCESS_CLOCK;
1406         return posix_cpu_timer_create(timer);
1407 }
1408 static int process_cpu_nsleep(const clockid_t which_clock, int flags,
1409                               const struct timespec64 *rqtp)
1410 {
1411         return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
1412 }
1413 static int thread_cpu_clock_getres(const clockid_t which_clock,
1414                                    struct timespec64 *tp)
1415 {
1416         return posix_cpu_clock_getres(THREAD_CLOCK, tp);
1417 }
1418 static int thread_cpu_clock_get(const clockid_t which_clock,
1419                                 struct timespec64 *tp)
1420 {
1421         return posix_cpu_clock_get(THREAD_CLOCK, tp);
1422 }
1423 static int thread_cpu_timer_create(struct k_itimer *timer)
1424 {
1425         timer->it_clock = THREAD_CLOCK;
1426         return posix_cpu_timer_create(timer);
1427 }
1428
1429 const struct k_clock clock_posix_cpu = {
1430         .clock_getres   = posix_cpu_clock_getres,
1431         .clock_set      = posix_cpu_clock_set,
1432         .clock_get      = posix_cpu_clock_get,
1433         .timer_create   = posix_cpu_timer_create,
1434         .nsleep         = posix_cpu_nsleep,
1435         .timer_set      = posix_cpu_timer_set,
1436         .timer_del      = posix_cpu_timer_del,
1437         .timer_get      = posix_cpu_timer_get,
1438         .timer_rearm    = posix_cpu_timer_rearm,
1439 };
1440
1441 const struct k_clock clock_process = {
1442         .clock_getres   = process_cpu_clock_getres,
1443         .clock_get      = process_cpu_clock_get,
1444         .timer_create   = process_cpu_timer_create,
1445         .nsleep         = process_cpu_nsleep,
1446 };
1447
1448 const struct k_clock clock_thread = {
1449         .clock_getres   = thread_cpu_clock_getres,
1450         .clock_get      = thread_cpu_clock_get,
1451         .timer_create   = thread_cpu_timer_create,
1452 };