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 // SPDX-License-Identifier: GPL-2.0+
 /*
  * 2002-10-15  Posix Clocks & timers
  *                           by George Anzinger george@mvista.com
  *               Copyright (C) 2002 2003 by MontaVista Software.
  *
  * 2004-06-01  Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
  *               Copyright (C) 2004 Boris Hu
  *
  * These are all the functions necessary to implement POSIX clocks & timers
  */
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/time.h>
 #include <linux/mutex.h>
 #include <linux/sched/task.h>
 
 #include <linux/uaccess.h>
 #include <linux/list.h>
 #include <linux/init.h>
 #include <linux/compiler.h>
 #include <linux/hash.h>
 #include <linux/posix-clock.h>
 #include <linux/posix-timers.h>
 #include <linux/syscalls.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 #include <linux/export.h>
 #include <linux/hashtable.h>
 #include <linux/compat.h>
 #include <linux/nospec.h>
 #include <linux/time_namespace.h>
 
 #include "timekeeping.h"
 #include "posix-timers.h"
 
 /*
  * Management arrays for POSIX timers. Timers are now kept in static hash table
  * with 512 entries.
  * Timer ids are allocated by local routine, which selects proper hash head by
  * key, constructed from current->signal address and per signal struct counter.
  * This keeps timer ids unique per process, but now they can intersect between
  * processes.
  */
 
 /*
  * Lets keep our timers in a slab cache :-)
  */
 static struct kmem_cache *posix_timers_cache;
 
 static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
 static DEFINE_SPINLOCK(hash_lock);
 
 static const struct k_clock * const posix_clocks[];
 static const struct k_clock *clockid_to_kclock(const clockid_t id);
 static const struct k_clock clock_realtime, clock_monotonic;
 
 /*
  * we assume that the new SIGEV_THREAD_ID shares no bits with the other
  * SIGEV values.  Here we put out an error if this assumption fails.
  */
 #if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
                        ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
 #error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
 #endif
 
 /*
  * The timer ID is turned into a timer address by idr_find().
  * Verifying a valid ID consists of:
  *
  * a) checking that idr_find() returns other than -1.
  * b) checking that the timer id matches the one in the timer itself.
  * c) that the timer owner is in the callers thread group.
  */
 
 /*
  * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
  *      to implement others.  This structure defines the various
  *      clocks.
  *
  * RESOLUTION: Clock resolution is used to round up timer and interval
  *      times, NOT to report clock times, which are reported with as
  *      much resolution as the system can muster.  In some cases this
  *      resolution may depend on the underlying clock hardware and
  *      may not be quantifiable until run time, and only then is the
  *      necessary code is written.  The standard says we should say
  *      something about this issue in the documentation...
  *
  * FUNCTIONS: The CLOCKs structure defines possible functions to
  *      handle various clock functions.
  *
  *      The standard POSIX timer management code assumes the
  *      following: 1.) The k_itimer struct (sched.h) is used for
  *      the timer.  2.) The list, it_lock, it_clock, it_id and
  *      it_pid fields are not modified by timer code.
  *
  * Permissions: It is assumed that the clock_settime() function defined
  *      for each clock will take care of permission checks.  Some
  *      clocks may be set able by any user (i.e. local process
  *      clocks) others not.  Currently the only set able clock we
  *      have is CLOCK_REALTIME and its high res counter part, both of
  *      which we beg off on and pass to do_sys_settimeofday().
  */
 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
 
 #define lock_timer(tid, flags)                         \
 ({  struct k_itimer *__timr;                       \
     __cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags));  \
     __timr;                                \
 })
 
 static int hash(struct signal_struct *sig, unsigned int nr)
 {
     return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
 }
 
 static struct k_itimer *__posix_timers_find(struct hlist_head *head,
                         struct signal_struct *sig,
                         timer_t id)
 {
     struct k_itimer *timer;
 
     hlist_for_each_entry_rcu(timer, head, t_hash,
                  lockdep_is_held(&hash_lock)) {
         if ((timer->it_signal == sig) && (timer->it_id == id))
             return timer;
     }
     return NULL;
 }
 
 static struct k_itimer *posix_timer_by_id(timer_t id)
 {
     struct signal_struct *sig = current->signal;
     struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
 
     return __posix_timers_find(head, sig, id);
 }
 
 static int posix_timer_add(struct k_itimer *timer)
 {
     struct signal_struct *sig = current->signal;
     int first_free_id = sig->posix_timer_id;
     struct hlist_head *head;
     int ret = -ENOENT;
 
     do {
         spin_lock(&hash_lock);
         head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
         if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
             hlist_add_head_rcu(&timer->t_hash, head);
             ret = sig->posix_timer_id;
         }
         if (++sig->posix_timer_id < 0)
             sig->posix_timer_id = 0;
         if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
             /* Loop over all possible ids completed */
             ret = -EAGAIN;
         spin_unlock(&hash_lock);
     } while (ret == -ENOENT);
     return ret;
 }
 
 static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
 {
     spin_unlock_irqrestore(&timr->it_lock, flags);
 }
 
 /* Get clock_realtime */
 static int posix_get_realtime_timespec(clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_real_ts64(tp);
     return 0;
 }
 
 static ktime_t posix_get_realtime_ktime(clockid_t which_clock)
 {
     return ktime_get_real();
 }
 
 /* Set clock_realtime */
 static int posix_clock_realtime_set(const clockid_t which_clock,
                     const struct timespec64 *tp)
 {
     return do_sys_settimeofday64(tp, NULL);
 }
 
 static int posix_clock_realtime_adj(const clockid_t which_clock,
                     struct __kernel_timex *t)
 {
     return do_adjtimex(t);
 }
 
 /*
  * Get monotonic time for posix timers
  */
 static int posix_get_monotonic_timespec(clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_ts64(tp);
     timens_add_monotonic(tp);
     return 0;
 }
 
 static ktime_t posix_get_monotonic_ktime(clockid_t which_clock)
 {
     return ktime_get();
 }
 
 /*
  * Get monotonic-raw time for posix timers
  */
 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_raw_ts64(tp);
     timens_add_monotonic(tp);
     return 0;
 }
 
 
 static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_coarse_real_ts64(tp);
     return 0;
 }
 
 static int posix_get_monotonic_coarse(clockid_t which_clock,
                         struct timespec64 *tp)
 {
     ktime_get_coarse_ts64(tp);
     timens_add_monotonic(tp);
     return 0;
 }
 
 static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *tp)
 {
     *tp = ktime_to_timespec64(KTIME_LOW_RES);
     return 0;
 }
 
 static int posix_get_boottime_timespec(const clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_boottime_ts64(tp);
     timens_add_boottime(tp);
     return 0;
 }
 
 static ktime_t posix_get_boottime_ktime(const clockid_t which_clock)
 {
     return ktime_get_boottime();
 }
 
 static int posix_get_tai_timespec(clockid_t which_clock, struct timespec64 *tp)
 {
     ktime_get_clocktai_ts64(tp);
     return 0;
 }
 
 static ktime_t posix_get_tai_ktime(clockid_t which_clock)
 {
     return ktime_get_clocktai();
 }
 
 static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
 {
     tp->tv_sec = 0;
     tp->tv_nsec = hrtimer_resolution;
     return 0;
 }
 
 /*
  * Initialize everything, well, just everything in Posix clocks/timers ;)
  */
 static __init int init_posix_timers(void)
 {
     posix_timers_cache = kmem_cache_create("posix_timers_cache",
                     sizeof(struct k_itimer), 0,
                     SLAB_PANIC | SLAB_ACCOUNT, NULL);
     return 0;
 }
 __initcall(init_posix_timers);
 
 /*
  * The siginfo si_overrun field and the return value of timer_getoverrun(2)
  * are of type int. Clamp the overrun value to INT_MAX
  */
 static inline int timer_overrun_to_int(struct k_itimer *timr, int baseval)
 {
     s64 sum = timr->it_overrun_last + (s64)baseval;
 
     return sum > (s64)INT_MAX ? INT_MAX : (int)sum;
 }
 
 static void common_hrtimer_rearm(struct k_itimer *timr)
 {
     struct hrtimer *timer = &timr->it.real.timer;
 
     timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
                         timr->it_interval);
     hrtimer_restart(timer);
 }
 
 /*
  * This function is exported for use by the signal deliver code.  It is
  * called just prior to the info block being released and passes that
  * block to us.  It's function is to update the overrun entry AND to
  * restart the timer.  It should only be called if the timer is to be
  * restarted (i.e. we have flagged this in the sys_private entry of the
  * info block).
  *
  * To protect against the timer going away while the interrupt is queued,
  * we require that the it_requeue_pending flag be set.
  */
 void posixtimer_rearm(struct kernel_siginfo *info)
 {
     struct k_itimer *timr;
     unsigned long flags;
 
     timr = lock_timer(info->si_tid, &flags);
     if (!timr)
         return;
 
     if (timr->it_interval && timr->it_requeue_pending == info->si_sys_private) {
         timr->kclock->timer_rearm(timr);
 
         timr->it_active = 1;
         timr->it_overrun_last = timr->it_overrun;
         timr->it_overrun = -1LL;
         ++timr->it_requeue_pending;
 
         info->si_overrun = timer_overrun_to_int(timr, info->si_overrun);
     }
 
     unlock_timer(timr, flags);
 }
 
 int posix_timer_event(struct k_itimer *timr, int si_private)
 {
     enum pid_type type;
     int ret;
     /*
      * FIXME: if ->sigq is queued we can race with
      * dequeue_signal()->posixtimer_rearm().
      *
      * If dequeue_signal() sees the "right" value of
      * si_sys_private it calls posixtimer_rearm().
      * We re-queue ->sigq and drop ->it_lock().
      * posixtimer_rearm() locks the timer
      * and re-schedules it while ->sigq is pending.
      * Not really bad, but not that we want.
      */
     timr->sigq->info.si_sys_private = si_private;
 
     type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID;
     ret = send_sigqueue(timr->sigq, timr->it_pid, type);
     /* If we failed to send the signal the timer stops. */
     return ret > 0;
 }
 
 /*
  * This function gets called when a POSIX.1b interval timer expires.  It
  * is used as a callback from the kernel internal timer.  The
  * run_timer_list code ALWAYS calls with interrupts on.
 
  * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
  */
 static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
 {
     struct k_itimer *timr;
     unsigned long flags;
     int si_private = 0;
     enum hrtimer_restart ret = HRTIMER_NORESTART;
 
     timr = container_of(timer, struct k_itimer, it.real.timer);
     spin_lock_irqsave(&timr->it_lock, flags);
 
     timr->it_active = 0;
     if (timr->it_interval != 0)
         si_private = ++timr->it_requeue_pending;
 
     if (posix_timer_event(timr, si_private)) {
         /*
          * signal was not sent because of sig_ignor
          * we will not get a call back to restart it AND
          * it should be restarted.
          */
         if (timr->it_interval != 0) {
             ktime_t now = hrtimer_cb_get_time(timer);
 
             /*
              * FIXME: What we really want, is to stop this
              * timer completely and restart it in case the
              * SIG_IGN is removed. This is a non trivial
              * change which involves sighand locking
              * (sigh !), which we don't want to do late in
              * the release cycle.
              *
              * For now we just let timers with an interval
              * less than a jiffie expire every jiffie to
              * avoid softirq starvation in case of SIG_IGN
              * and a very small interval, which would put
              * the timer right back on the softirq pending
              * list. By moving now ahead of time we trick
              * hrtimer_forward() to expire the timer
              * later, while we still maintain the overrun
              * accuracy, but have some inconsistency in
              * the timer_gettime() case. This is at least
              * better than a starved softirq. A more
              * complex fix which solves also another related
              * inconsistency is already in the pipeline.
              */
 #ifdef CONFIG_HIGH_RES_TIMERS
             {
                 ktime_t kj = NSEC_PER_SEC / HZ;
 
                 if (timr->it_interval < kj)
                     now = ktime_add(now, kj);
             }
 #endif
             timr->it_overrun += hrtimer_forward(timer, now,
                                 timr->it_interval);
             ret = HRTIMER_RESTART;
             ++timr->it_requeue_pending;
             timr->it_active = 1;
         }
     }
 
     unlock_timer(timr, flags);
     return ret;
 }
 
 static struct pid *good_sigevent(sigevent_t * event)
 {
     struct pid *pid = task_tgid(current);
     struct task_struct *rtn;
 
     switch (event->sigev_notify) {
     case SIGEV_SIGNAL | SIGEV_THREAD_ID:
         pid = find_vpid(event->sigev_notify_thread_id);
         rtn = pid_task(pid, PIDTYPE_PID);
         if (!rtn || !same_thread_group(rtn, current))
             return NULL;
         fallthrough;
     case SIGEV_SIGNAL:
     case SIGEV_THREAD:
         if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX)
             return NULL;
         fallthrough;
     case SIGEV_NONE:
         return pid;
     default:
         return NULL;
     }
 }
 
 static struct k_itimer * alloc_posix_timer(void)
 {
     struct k_itimer *tmr;
     tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
     if (!tmr)
         return tmr;
     if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
         kmem_cache_free(posix_timers_cache, tmr);
         return NULL;
     }
     clear_siginfo(&tmr->sigq->info);
     return tmr;
 }
 
 static void k_itimer_rcu_free(struct rcu_head *head)
 {
     struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
 
     kmem_cache_free(posix_timers_cache, tmr);
 }
 
 #define IT_ID_SET   1
 #define IT_ID_NOT_SET   0
 static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
 {
     if (it_id_set) {
         unsigned long flags;
         spin_lock_irqsave(&hash_lock, flags);
         hlist_del_rcu(&tmr->t_hash);
         spin_unlock_irqrestore(&hash_lock, flags);
     }
     put_pid(tmr->it_pid);
     sigqueue_free(tmr->sigq);
     call_rcu(&tmr->rcu, k_itimer_rcu_free);
 }
 
 static int common_timer_create(struct k_itimer *new_timer)
 {
     hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
     return 0;
 }
 
 /* Create a POSIX.1b interval timer. */
 static int do_timer_create(clockid_t which_clock, struct sigevent *event,
                timer_t __user *created_timer_id)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct k_itimer *new_timer;
     int error, new_timer_id;
     int it_id_set = IT_ID_NOT_SET;
 
     if (!kc)
         return -EINVAL;
     if (!kc->timer_create)
         return -EOPNOTSUPP;
 
     new_timer = alloc_posix_timer();
     if (unlikely(!new_timer))
         return -EAGAIN;
 
     spin_lock_init(&new_timer->it_lock);
     new_timer_id = posix_timer_add(new_timer);
     if (new_timer_id < 0) {
         error = new_timer_id;
         goto out;
     }
 
     it_id_set = IT_ID_SET;
     new_timer->it_id = (timer_t) new_timer_id;
     new_timer->it_clock = which_clock;
     new_timer->kclock = kc;
     new_timer->it_overrun = -1LL;
 
     if (event) {
         rcu_read_lock();
         new_timer->it_pid = get_pid(good_sigevent(event));
         rcu_read_unlock();
         if (!new_timer->it_pid) {
             error = -EINVAL;
             goto out;
         }
         new_timer->it_sigev_notify     = event->sigev_notify;
         new_timer->sigq->info.si_signo = event->sigev_signo;
         new_timer->sigq->info.si_value = event->sigev_value;
     } else {
         new_timer->it_sigev_notify     = SIGEV_SIGNAL;
         new_timer->sigq->info.si_signo = SIGALRM;
         memset(&new_timer->sigq->info.si_value, 0, sizeof(sigval_t));
         new_timer->sigq->info.si_value.sival_int = new_timer->it_id;
         new_timer->it_pid = get_pid(task_tgid(current));
     }
 
     new_timer->sigq->info.si_tid   = new_timer->it_id;
     new_timer->sigq->info.si_code  = SI_TIMER;
 
     if (copy_to_user(created_timer_id,
              &new_timer_id, sizeof (new_timer_id))) {
         error = -EFAULT;
         goto out;
     }
 
     error = kc->timer_create(new_timer);
     if (error)
         goto out;
 
     spin_lock_irq(&current->sighand->siglock);
     new_timer->it_signal = current->signal;
     list_add(&new_timer->list, &current->signal->posix_timers);
     spin_unlock_irq(&current->sighand->siglock);
 
     return 0;
     /*
      * In the case of the timer belonging to another task, after
      * the task is unlocked, the timer is owned by the other task
      * and may cease to exist at any time.  Don't use or modify
      * new_timer after the unlock call.
      */
 out:
     release_posix_timer(new_timer, it_id_set);
     return error;
 }
 
 SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
         struct sigevent __user *, timer_event_spec,
         timer_t __user *, created_timer_id)
 {
     if (timer_event_spec) {
         sigevent_t event;
 
         if (copy_from_user(&event, timer_event_spec, sizeof (event)))
             return -EFAULT;
         return do_timer_create(which_clock, &event, created_timer_id);
     }
     return do_timer_create(which_clock, NULL, created_timer_id);
 }
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock,
                struct compat_sigevent __user *, timer_event_spec,
                timer_t __user *, created_timer_id)
 {
     if (timer_event_spec) {
         sigevent_t event;
 
         if (get_compat_sigevent(&event, timer_event_spec))
             return -EFAULT;
         return do_timer_create(which_clock, &event, created_timer_id);
     }
     return do_timer_create(which_clock, NULL, created_timer_id);
 }
 #endif
 
 /*
  * Locking issues: We need to protect the result of the id look up until
  * we get the timer locked down so it is not deleted under us.  The
  * removal is done under the idr spinlock so we use that here to bridge
  * the find to the timer lock.  To avoid a dead lock, the timer id MUST
  * be release with out holding the timer lock.
  */
 static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
 {
     struct k_itimer *timr;
 
     /*
      * timer_t could be any type >= int and we want to make sure any
      * @timer_id outside positive int range fails lookup.
      */
     if ((unsigned long long)timer_id > INT_MAX)
         return NULL;
 
     rcu_read_lock();
     timr = posix_timer_by_id(timer_id);
     if (timr) {
         spin_lock_irqsave(&timr->it_lock, *flags);
         if (timr->it_signal == current->signal) {
             rcu_read_unlock();
             return timr;
         }
         spin_unlock_irqrestore(&timr->it_lock, *flags);
     }
     rcu_read_unlock();
 
     return NULL;
 }
 
 static ktime_t common_hrtimer_remaining(struct k_itimer *timr, ktime_t now)
 {
     struct hrtimer *timer = &timr->it.real.timer;
 
     return __hrtimer_expires_remaining_adjusted(timer, now);
 }
 
 static s64 common_hrtimer_forward(struct k_itimer *timr, ktime_t now)
 {
     struct hrtimer *timer = &timr->it.real.timer;
 
     return hrtimer_forward(timer, now, timr->it_interval);
 }
 
 /*
  * Get the time remaining on a POSIX.1b interval timer.  This function
  * is ALWAYS called with spin_lock_irq on the timer, thus it must not
  * mess with irq.
  *
  * We have a couple of messes to clean up here.  First there is the case
  * of a timer that has a requeue pending.  These timers should appear to
  * be in the timer list with an expiry as if we were to requeue them
  * now.
  *
  * The second issue is the SIGEV_NONE timer which may be active but is
  * not really ever put in the timer list (to save system resources).
  * This timer may be expired, and if so, we will do it here.  Otherwise
  * it is the same as a requeue pending timer WRT to what we should
  * report.
  */
 void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
 {
     const struct k_clock *kc = timr->kclock;
     ktime_t now, remaining, iv;
     bool sig_none;
 
     sig_none = timr->it_sigev_notify == SIGEV_NONE;
     iv = timr->it_interval;
 
     /* interval timer ? */
     if (iv) {
         cur_setting->it_interval = ktime_to_timespec64(iv);
     } else if (!timr->it_active) {
         /*
          * SIGEV_NONE oneshot timers are never queued. Check them
          * below.
          */
         if (!sig_none)
             return;
     }
 
     now = kc->clock_get_ktime(timr->it_clock);
 
     /*
      * When a requeue is pending or this is a SIGEV_NONE timer move the
      * expiry time forward by intervals, so expiry is > now.
      */
     if (iv && (timr->it_requeue_pending & REQUEUE_PENDING || sig_none))
         timr->it_overrun += kc->timer_forward(timr, now);
 
     remaining = kc->timer_remaining(timr, now);
     /* Return 0 only, when the timer is expired and not pending */
     if (remaining <= 0) {
         /*
          * A single shot SIGEV_NONE timer must return 0, when
          * it is expired !
          */
         if (!sig_none)
             cur_setting->it_value.tv_nsec = 1;
     } else {
         cur_setting->it_value = ktime_to_timespec64(remaining);
     }
 }
 
 /* Get the time remaining on a POSIX.1b interval timer. */
 static int do_timer_gettime(timer_t timer_id,  struct itimerspec64 *setting)
 {
     struct k_itimer *timr;
     const struct k_clock *kc;
     unsigned long flags;
     int ret = 0;
 
     timr = lock_timer(timer_id, &flags);
     if (!timr)
         return -EINVAL;
 
     memset(setting, 0, sizeof(*setting));
     kc = timr->kclock;
     if (WARN_ON_ONCE(!kc || !kc->timer_get))
         ret = -EINVAL;
     else
         kc->timer_get(timr, setting);
 
     unlock_timer(timr, flags);
     return ret;
 }
 
 /* Get the time remaining on a POSIX.1b interval timer. */
 SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
         struct __kernel_itimerspec __user *, setting)
 {
     struct itimerspec64 cur_setting;
 
     int ret = do_timer_gettime(timer_id, &cur_setting);
     if (!ret) {
         if (put_itimerspec64(&cur_setting, setting))
             ret = -EFAULT;
     }
     return ret;
 }
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
 SYSCALL_DEFINE2(timer_gettime32, timer_t, timer_id,
         struct old_itimerspec32 __user *, setting)
 {
     struct itimerspec64 cur_setting;
 
     int ret = do_timer_gettime(timer_id, &cur_setting);
     if (!ret) {
         if (put_old_itimerspec32(&cur_setting, setting))
             ret = -EFAULT;
     }
     return ret;
 }
 
 #endif
 
 /*
  * Get the number of overruns of a POSIX.1b interval timer.  This is to
  * be the overrun of the timer last delivered.  At the same time we are
  * accumulating overruns on the next timer.  The overrun is frozen when
  * the signal is delivered, either at the notify time (if the info block
  * is not queued) or at the actual delivery time (as we are informed by
  * the call back to posixtimer_rearm().  So all we need to do is
  * to pick up the frozen overrun.
  */
 SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
 {
     struct k_itimer *timr;
     int overrun;
     unsigned long flags;
 
     timr = lock_timer(timer_id, &flags);
     if (!timr)
         return -EINVAL;
 
     overrun = timer_overrun_to_int(timr, 0);
     unlock_timer(timr, flags);
 
     return overrun;
 }
 
 static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
                    bool absolute, bool sigev_none)
 {
     struct hrtimer *timer = &timr->it.real.timer;
     enum hrtimer_mode mode;
 
     mode = absolute ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
     /*
      * Posix magic: Relative CLOCK_REALTIME timers are not affected by
      * clock modifications, so they become CLOCK_MONOTONIC based under the
      * hood. See hrtimer_init(). Update timr->kclock, so the generic
      * functions which use timr->kclock->clock_get_*() work.
      *
      * Note: it_clock stays unmodified, because the next timer_set() might
      * use ABSTIME, so it needs to switch back.
      */
     if (timr->it_clock == CLOCK_REALTIME)
         timr->kclock = absolute ? &clock_realtime : &clock_monotonic;
 
     hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
     timr->it.real.timer.function = posix_timer_fn;
 
     if (!absolute)
         expires = ktime_add_safe(expires, timer->base->get_time());
     hrtimer_set_expires(timer, expires);
 
     if (!sigev_none)
         hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }
 
 static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
 {
     return hrtimer_try_to_cancel(&timr->it.real.timer);
 }
 
 static void common_timer_wait_running(struct k_itimer *timer)
 {
     hrtimer_cancel_wait_running(&timer->it.real.timer);
 }
 
 /*
  * On PREEMPT_RT this prevent priority inversion against softirq kthread in
  * case it gets preempted while executing a timer callback. See comments in
  * hrtimer_cancel_wait_running. For PREEMPT_RT=n this just results in a
  * cpu_relax().
  */
 static struct k_itimer *timer_wait_running(struct k_itimer *timer,
                        unsigned long *flags)
 {
     const struct k_clock *kc = READ_ONCE(timer->kclock);
     timer_t timer_id = READ_ONCE(timer->it_id);
 
     /* Prevent kfree(timer) after dropping the lock */
     rcu_read_lock();
     unlock_timer(timer, *flags);
 
     if (!WARN_ON_ONCE(!kc->timer_wait_running))
         kc->timer_wait_running(timer);
 
     rcu_read_unlock();
     /* Relock the timer. It might be not longer hashed. */
     return lock_timer(timer_id, flags);
 }
 
 /* Set a POSIX.1b interval timer. */
 int common_timer_set(struct k_itimer *timr, int flags,
              struct itimerspec64 *new_setting,
              struct itimerspec64 *old_setting)
 {
     const struct k_clock *kc = timr->kclock;
     bool sigev_none;
     ktime_t expires;
 
     if (old_setting)
         common_timer_get(timr, old_setting);
 
     /* Prevent rearming by clearing the interval */
     timr->it_interval = 0;
     /*
      * Careful here. On SMP systems the timer expiry function could be
      * active and spinning on timr->it_lock.
      */
     if (kc->timer_try_to_cancel(timr) < 0)
         return TIMER_RETRY;
 
     timr->it_active = 0;
     timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
         ~REQUEUE_PENDING;
     timr->it_overrun_last = 0;
 
     /* Switch off the timer when it_value is zero */
     if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
         return 0;
 
     timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
     expires = timespec64_to_ktime(new_setting->it_value);
     if (flags & TIMER_ABSTIME)
         expires = timens_ktime_to_host(timr->it_clock, expires);
     sigev_none = timr->it_sigev_notify == SIGEV_NONE;
 
     kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);
     timr->it_active = !sigev_none;
     return 0;
 }
 
 static int do_timer_settime(timer_t timer_id, int tmr_flags,
                 struct itimerspec64 *new_spec64,
                 struct itimerspec64 *old_spec64)
 {
     const struct k_clock *kc;
     struct k_itimer *timr;
     unsigned long flags;
     int error = 0;
 
     if (!timespec64_valid(&new_spec64->it_interval) ||
         !timespec64_valid(&new_spec64->it_value))
         return -EINVAL;
 
     if (old_spec64)
         memset(old_spec64, 0, sizeof(*old_spec64));
 
     timr = lock_timer(timer_id, &flags);
 retry:
     if (!timr)
         return -EINVAL;
 
     kc = timr->kclock;
     if (WARN_ON_ONCE(!kc || !kc->timer_set))
         error = -EINVAL;
     else
         error = kc->timer_set(timr, tmr_flags, new_spec64, old_spec64);
 
     if (error == TIMER_RETRY) {
         // We already got the old time...
         old_spec64 = NULL;
         /* Unlocks and relocks the timer if it still exists */
         timr = timer_wait_running(timr, &flags);
         goto retry;
     }
     unlock_timer(timr, flags);
 
     return error;
 }
 
 /* Set a POSIX.1b interval timer */
 SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
         const struct __kernel_itimerspec __user *, new_setting,
         struct __kernel_itimerspec __user *, old_setting)
 {
     struct itimerspec64 new_spec, old_spec;
     struct itimerspec64 *rtn = old_setting ? &old_spec : NULL;
     int error = 0;
 
     if (!new_setting)
         return -EINVAL;
 
     if (get_itimerspec64(&new_spec, new_setting))
         return -EFAULT;
 
     error = do_timer_settime(timer_id, flags, &new_spec, rtn);
     if (!error && old_setting) {
         if (put_itimerspec64(&old_spec, old_setting))
             error = -EFAULT;
     }
     return error;
 }
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 SYSCALL_DEFINE4(timer_settime32, timer_t, timer_id, int, flags,
         struct old_itimerspec32 __user *, new,
         struct old_itimerspec32 __user *, old)
 {
     struct itimerspec64 new_spec, old_spec;
     struct itimerspec64 *rtn = old ? &old_spec : NULL;
     int error = 0;
 
     if (!new)
         return -EINVAL;
     if (get_old_itimerspec32(&new_spec, new))
         return -EFAULT;
 
     error = do_timer_settime(timer_id, flags, &new_spec, rtn);
     if (!error && old) {
         if (put_old_itimerspec32(&old_spec, old))
             error = -EFAULT;
     }
     return error;
 }
 #endif
 
 int common_timer_del(struct k_itimer *timer)
 {
     const struct k_clock *kc = timer->kclock;
 
     timer->it_interval = 0;
     if (kc->timer_try_to_cancel(timer) < 0)
         return TIMER_RETRY;
     timer->it_active = 0;
     return 0;
 }
 
 static inline int timer_delete_hook(struct k_itimer *timer)
 {
     const struct k_clock *kc = timer->kclock;
 
     if (WARN_ON_ONCE(!kc || !kc->timer_del))
         return -EINVAL;
     return kc->timer_del(timer);
 }
 
 /* Delete a POSIX.1b interval timer. */
 SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
 {
     struct k_itimer *timer;
     unsigned long flags;
 
     timer = lock_timer(timer_id, &flags);
 
 retry_delete:
     if (!timer)
         return -EINVAL;
 
     if (unlikely(timer_delete_hook(timer) == TIMER_RETRY)) {
         /* Unlocks and relocks the timer if it still exists */
         timer = timer_wait_running(timer, &flags);
         goto retry_delete;
     }
 
     spin_lock(&current->sighand->siglock);
     list_del(&timer->list);
     spin_unlock(&current->sighand->siglock);
     /*
      * This keeps any tasks waiting on the spin lock from thinking
      * they got something (see the lock code above).
      */
     timer->it_signal = NULL;
 
     unlock_timer(timer, flags);
     release_posix_timer(timer, IT_ID_SET);
     return 0;
 }
 
 /*
  * return timer owned by the process, used by exit_itimers
  */
 static void itimer_delete(struct k_itimer *timer)
 {
 retry_delete:
     spin_lock_irq(&timer->it_lock);
 
     if (timer_delete_hook(timer) == TIMER_RETRY) {
         spin_unlock_irq(&timer->it_lock);
         goto retry_delete;
     }
     list_del(&timer->list);
 
     spin_unlock_irq(&timer->it_lock);
     release_posix_timer(timer, IT_ID_SET);
 }
 
 /*
  * This is called by do_exit or de_thread, only when nobody else can
  * modify the signal->posix_timers list. Yet we need sighand->siglock
  * to prevent the race with /proc/pid/timers.
  */
 void exit_itimers(struct task_struct *tsk)
 {
     struct list_head timers;
     struct k_itimer *tmr;
 
     if (list_empty(&tsk->signal->posix_timers))
         return;
 
     spin_lock_irq(&tsk->sighand->siglock);
     list_replace_init(&tsk->signal->posix_timers, &timers);
     spin_unlock_irq(&tsk->sighand->siglock);
 
     while (!list_empty(&timers)) {
         tmr = list_first_entry(&timers, struct k_itimer, list);
         itimer_delete(tmr);
     }
 }
 
 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
         const struct __kernel_timespec __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 new_tp;
 
     if (!kc || !kc->clock_set)
         return -EINVAL;
 
     if (get_timespec64(&new_tp, tp))
         return -EFAULT;
 
     return kc->clock_set(which_clock, &new_tp);
 }
 
 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
         struct __kernel_timespec __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 kernel_tp;
     int error;
 
     if (!kc)
         return -EINVAL;
 
     error = kc->clock_get_timespec(which_clock, &kernel_tp);
 
     if (!error && put_timespec64(&kernel_tp, tp))
         error = -EFAULT;
 
     return error;
 }
 
 int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * ktx)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
 
     if (!kc)
         return -EINVAL;
     if (!kc->clock_adj)
         return -EOPNOTSUPP;
 
     return kc->clock_adj(which_clock, ktx);
 }
 
 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
         struct __kernel_timex __user *, utx)
 {
     struct __kernel_timex ktx;
     int err;
 
     if (copy_from_user(&ktx, utx, sizeof(ktx)))
         return -EFAULT;
 
     err = do_clock_adjtime(which_clock, &ktx);
 
     if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
         return -EFAULT;
 
     return err;
 }
 
 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
         struct __kernel_timespec __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 rtn_tp;
     int error;
 
     if (!kc)
         return -EINVAL;
 
     error = kc->clock_getres(which_clock, &rtn_tp);
 
     if (!error && tp && put_timespec64(&rtn_tp, tp))
         error = -EFAULT;
 
     return error;
 }
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
 SYSCALL_DEFINE2(clock_settime32, clockid_t, which_clock,
         struct old_timespec32 __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 ts;
 
     if (!kc || !kc->clock_set)
         return -EINVAL;
 
     if (get_old_timespec32(&ts, tp))
         return -EFAULT;
 
     return kc->clock_set(which_clock, &ts);
 }
 
 SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
         struct old_timespec32 __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 ts;
     int err;
 
     if (!kc)
         return -EINVAL;
 
     err = kc->clock_get_timespec(which_clock, &ts);
 
     if (!err && put_old_timespec32(&ts, tp))
         err = -EFAULT;
 
     return err;
 }
 
 SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
         struct old_timex32 __user *, utp)
 {
     struct __kernel_timex ktx;
     int err;
 
     err = get_old_timex32(&ktx, utp);
     if (err)
         return err;
 
     err = do_clock_adjtime(which_clock, &ktx);
 
     if (err >= 0 && put_old_timex32(utp, &ktx))
         return -EFAULT;
 
     return err;
 }
 
 SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
         struct old_timespec32 __user *, tp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 ts;
     int err;
 
     if (!kc)
         return -EINVAL;
 
     err = kc->clock_getres(which_clock, &ts);
     if (!err && tp && put_old_timespec32(&ts, tp))
         return -EFAULT;
 
     return err;
 }
 
 #endif
 
 /*
  * nanosleep for monotonic and realtime clocks
  */
 static int common_nsleep(const clockid_t which_clock, int flags,
              const struct timespec64 *rqtp)
 {
     ktime_t texp = timespec64_to_ktime(*rqtp);
 
     return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
                  HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
                  which_clock);
 }
 
 static int common_nsleep_timens(const clockid_t which_clock, int flags,
              const struct timespec64 *rqtp)
 {
     ktime_t texp = timespec64_to_ktime(*rqtp);
 
     if (flags & TIMER_ABSTIME)
         texp = timens_ktime_to_host(which_clock, texp);
 
     return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
                  HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
                  which_clock);
 }
 
 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
         const struct __kernel_timespec __user *, rqtp,
         struct __kernel_timespec __user *, rmtp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 t;
 
     if (!kc)
         return -EINVAL;
     if (!kc->nsleep)
         return -EOPNOTSUPP;
 
     if (get_timespec64(&t, rqtp))
         return -EFAULT;
 
     if (!timespec64_valid(&t))
         return -EINVAL;
     if (flags & TIMER_ABSTIME)
         rmtp = NULL;
     current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
     current->restart_block.nanosleep.rmtp = rmtp;
 
     return kc->nsleep(which_clock, flags, &t);
 }
 
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
 SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
         struct old_timespec32 __user *, rqtp,
         struct old_timespec32 __user *, rmtp)
 {
     const struct k_clock *kc = clockid_to_kclock(which_clock);
     struct timespec64 t;
 
     if (!kc)
         return -EINVAL;
     if (!kc->nsleep)
         return -EOPNOTSUPP;
 
     if (get_old_timespec32(&t, rqtp))
         return -EFAULT;
 
     if (!timespec64_valid(&t))
         return -EINVAL;
     if (flags & TIMER_ABSTIME)
         rmtp = NULL;
     current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
     current->restart_block.nanosleep.compat_rmtp = rmtp;
 
     return kc->nsleep(which_clock, flags, &t);
 }
 
 #endif
 
 static const struct k_clock clock_realtime = {
     .clock_getres       = posix_get_hrtimer_res,
     .clock_get_timespec = posix_get_realtime_timespec,
     .clock_get_ktime    = posix_get_realtime_ktime,
     .clock_set      = posix_clock_realtime_set,
     .clock_adj      = posix_clock_realtime_adj,
     .nsleep         = common_nsleep,
     .timer_create       = common_timer_create,
     .timer_set      = common_timer_set,
     .timer_get      = common_timer_get,
     .timer_del      = common_timer_del,
     .timer_rearm        = common_hrtimer_rearm,
     .timer_forward      = common_hrtimer_forward,
     .timer_remaining    = common_hrtimer_remaining,
     .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
     .timer_wait_running = common_timer_wait_running,
     .timer_arm      = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_monotonic = {
     .clock_getres       = posix_get_hrtimer_res,
     .clock_get_timespec = posix_get_monotonic_timespec,
     .clock_get_ktime    = posix_get_monotonic_ktime,
     .nsleep         = common_nsleep_timens,
     .timer_create       = common_timer_create,
     .timer_set      = common_timer_set,
     .timer_get      = common_timer_get,
     .timer_del      = common_timer_del,
     .timer_rearm        = common_hrtimer_rearm,
     .timer_forward      = common_hrtimer_forward,
     .timer_remaining    = common_hrtimer_remaining,
     .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
     .timer_wait_running = common_timer_wait_running,
     .timer_arm      = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_monotonic_raw = {
     .clock_getres       = posix_get_hrtimer_res,
     .clock_get_timespec = posix_get_monotonic_raw,
 };
 
 static const struct k_clock clock_realtime_coarse = {
     .clock_getres       = posix_get_coarse_res,
     .clock_get_timespec = posix_get_realtime_coarse,
 };
 
 static const struct k_clock clock_monotonic_coarse = {
     .clock_getres       = posix_get_coarse_res,
     .clock_get_timespec = posix_get_monotonic_coarse,
 };
 
 static const struct k_clock clock_tai = {
     .clock_getres       = posix_get_hrtimer_res,
     .clock_get_ktime    = posix_get_tai_ktime,
     .clock_get_timespec = posix_get_tai_timespec,
     .nsleep         = common_nsleep,
     .timer_create       = common_timer_create,
     .timer_set      = common_timer_set,
     .timer_get      = common_timer_get,
     .timer_del      = common_timer_del,
     .timer_rearm        = common_hrtimer_rearm,
     .timer_forward      = common_hrtimer_forward,
     .timer_remaining    = common_hrtimer_remaining,
     .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
     .timer_wait_running = common_timer_wait_running,
     .timer_arm      = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_boottime = {
     .clock_getres       = posix_get_hrtimer_res,
     .clock_get_ktime    = posix_get_boottime_ktime,
     .clock_get_timespec = posix_get_boottime_timespec,
     .nsleep         = common_nsleep_timens,
     .timer_create       = common_timer_create,
     .timer_set      = common_timer_set,
     .timer_get      = common_timer_get,
     .timer_del      = common_timer_del,
     .timer_rearm        = common_hrtimer_rearm,
     .timer_forward      = common_hrtimer_forward,
     .timer_remaining    = common_hrtimer_remaining,
     .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
     .timer_wait_running = common_timer_wait_running,
     .timer_arm      = common_hrtimer_arm,
 };
 
 static const struct k_clock * const posix_clocks[] = {
     [CLOCK_REALTIME]        = &clock_realtime,
     [CLOCK_MONOTONIC]       = &clock_monotonic,
     [CLOCK_PROCESS_CPUTIME_ID]  = &clock_process,
     [CLOCK_THREAD_CPUTIME_ID]   = &clock_thread,
     [CLOCK_MONOTONIC_RAW]       = &clock_monotonic_raw,
     [CLOCK_REALTIME_COARSE]     = &clock_realtime_coarse,
     [CLOCK_MONOTONIC_COARSE]    = &clock_monotonic_coarse,
     [CLOCK_BOOTTIME]        = &clock_boottime,
     [CLOCK_REALTIME_ALARM]      = &alarm_clock,
     [CLOCK_BOOTTIME_ALARM]      = &alarm_clock,
     [CLOCK_TAI]         = &clock_tai,
 };
 
 static const struct k_clock *clockid_to_kclock(const clockid_t id)
 {
     clockid_t idx = id;
 
     if (id < 0) {
         return (id & CLOCKFD_MASK) == CLOCKFD ?
             &clock_posix_dynamic : &clock_posix_cpu;
     }
 
     if (id >= ARRAY_SIZE(posix_clocks))
         return NULL;
 
     return posix_clocks[array_index_nospec(idx, ARRAY_SIZE(posix_clocks))];
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team