// 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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; struct hlist_head *head; unsigned int cnt, id; /* * FIXME: Replace this by a per signal struct xarray once there is * a plan to handle the resulting CRIU regression gracefully. */ for (cnt = 0; cnt <= INT_MAX; cnt++) { spin_lock(&hash_lock); id = sig->next_posix_timer_id; /* Write the next ID back. Clamp it to the positive space */ sig->next_posix_timer_id = (id + 1) & INT_MAX; head = &posix_timers_hashtable[hash(sig, id)]; if (!__posix_timers_find(head, sig, id)) { hlist_add_head_rcu(&timer->t_hash, head); spin_unlock(&hash_lock); return id; } spin_unlock(&hash_lock); } /* POSIX return code when no timer ID could be allocated */ return -EAGAIN; } 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(¤t->sighand->siglock); new_timer->it_signal = current->signal; list_add(&new_timer->list, ¤t->signal->posix_timers); spin_unlock_irq(¤t->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); /* * kc->timer_wait_running() might drop RCU lock. So @timer * cannot be touched anymore after the function returns! */ 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(¤t->sighand->siglock); list_del(&timer->list); spin_unlock(¤t->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; } /* * Delete a timer if it is armed, remove it from the hash and schedule it * for RCU freeing. */ static void itimer_delete(struct k_itimer *timer) { unsigned long flags; /* * irqsave is required to make timer_wait_running() work. */ spin_lock_irqsave(&timer->it_lock, flags); retry_delete: /* * Even if the timer is not longer accessible from other tasks * it still might be armed and queued in the underlying timer * mechanism. Worse, that timer mechanism might run the expiry * function concurrently. */ if (timer_delete_hook(timer) == TIMER_RETRY) { /* * Timer is expired concurrently, prevent livelocks * and pointless spinning on RT. * * timer_wait_running() drops timer::it_lock, which opens * the possibility for another task to delete the timer. * * That's not possible here because this is invoked from * do_exit() only for the last thread of the thread group. * So no other task can access and delete that timer. */ if (WARN_ON_ONCE(timer_wait_running(timer, &flags) != timer)) return; goto retry_delete; } list_del(&timer->list); spin_unlock_irqrestore(&timer->it_lock, flags); release_posix_timer(timer, IT_ID_SET); } /* * Invoked from do_exit() when the last thread of a thread group exits. * At that point no other task can access the timers of the dying * task anymore. */ void exit_itimers(struct task_struct *tsk) { struct list_head timers; struct k_itimer *tmr; if (list_empty(&tsk->signal->posix_timers)) return; /* Protect against concurrent read via /proc/$PID/timers */ spin_lock_irq(&tsk->sighand->siglock); list_replace_init(&tsk->signal->posix_timers, &timers); spin_unlock_irq(&tsk->sighand->siglock); /* The timers are not longer accessible via tsk::signal */ 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.fn = do_no_restart_syscall; 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.fn = do_no_restart_syscall; 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))]; }