--- /dev/null
+/*
+ * linux/kernel/posix-timers.c
+ *
+ *
+ * 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
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
+ */
+
+/* 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 <asm/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 "timekeeping.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);
+
+/*
+ * 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
+
+/*
+ * parisc wants ENOTSUP instead of EOPNOTSUPP
+ */
+#ifndef ENOTSUP
+# define ENANOSLEEP_NOTSUP EOPNOTSUPP
+#else
+# define ENANOSLEEP_NOTSUP ENOTSUP
+#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_clock posix_clocks[MAX_CLOCKS];
+
+/*
+ * These ones are defined below.
+ */
+static int common_nsleep(const clockid_t, int flags, struct timespec *t,
+ struct timespec __user *rmtp);
+static int common_timer_create(struct k_itimer *new_timer);
+static void common_timer_get(struct k_itimer *, struct itimerspec *);
+static int common_timer_set(struct k_itimer *, int,
+ struct itimerspec *, struct itimerspec *);
+static int common_timer_del(struct k_itimer *timer);
+
+static enum hrtimer_restart posix_timer_fn(struct hrtimer *data);
+
+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) {
+ 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_clock_realtime_get(clockid_t which_clock, struct timespec *tp)
+{
+ ktime_get_real_ts(tp);
+ return 0;
+}
+
+/* Set clock_realtime */
+static int posix_clock_realtime_set(const clockid_t which_clock,
+ const struct timespec *tp)
+{
+ return do_sys_settimeofday(tp, NULL);
+}
+
+static int posix_clock_realtime_adj(const clockid_t which_clock,
+ struct timex *t)
+{
+ return do_adjtimex(t);
+}
+
+/*
+ * Get monotonic time for posix timers
+ */
+static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
+{
+ ktime_get_ts(tp);
+ return 0;
+}
+
+/*
+ * Get monotonic-raw time for posix timers
+ */
+static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
+{
+ getrawmonotonic(tp);
+ return 0;
+}
+
+
+static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
+{
+ *tp = current_kernel_time();
+ return 0;
+}
+
+static int posix_get_monotonic_coarse(clockid_t which_clock,
+ struct timespec *tp)
+{
+ *tp = get_monotonic_coarse();
+ return 0;
+}
+
+static int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
+{
+ *tp = ktime_to_timespec(KTIME_LOW_RES);
+ return 0;
+}
+
+static int posix_get_boottime(const clockid_t which_clock, struct timespec *tp)
+{
+ get_monotonic_boottime(tp);
+ return 0;
+}
+
+static int posix_get_tai(clockid_t which_clock, struct timespec *tp)
+{
+ timekeeping_clocktai(tp);
+ return 0;
+}
+
+/*
+ * Initialize everything, well, just everything in Posix clocks/timers ;)
+ */
+static __init int init_posix_timers(void)
+{
+ struct k_clock clock_realtime = {
+ .clock_getres = hrtimer_get_res,
+ .clock_get = posix_clock_realtime_get,
+ .clock_set = posix_clock_realtime_set,
+ .clock_adj = posix_clock_realtime_adj,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+ };
+ struct k_clock clock_monotonic = {
+ .clock_getres = hrtimer_get_res,
+ .clock_get = posix_ktime_get_ts,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+ };
+ struct k_clock clock_monotonic_raw = {
+ .clock_getres = hrtimer_get_res,
+ .clock_get = posix_get_monotonic_raw,
+ };
+ struct k_clock clock_realtime_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_realtime_coarse,
+ };
+ struct k_clock clock_monotonic_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_monotonic_coarse,
+ };
+ struct k_clock clock_tai = {
+ .clock_getres = hrtimer_get_res,
+ .clock_get = posix_get_tai,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+ };
+ struct k_clock clock_boottime = {
+ .clock_getres = hrtimer_get_res,
+ .clock_get = posix_get_boottime,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+ };
+
+ posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
+ posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
+ posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
+ posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
+ posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
+ posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime);
+ posix_timers_register_clock(CLOCK_TAI, &clock_tai);
+
+ posix_timers_cache = kmem_cache_create("posix_timers_cache",
+ sizeof (struct k_itimer), 0, SLAB_PANIC,
+ NULL);
+ return 0;
+}
+
+__initcall(init_posix_timers);
+
+static void schedule_next_timer(struct k_itimer *timr)
+{
+ struct hrtimer *timer = &timr->it.real.timer;
+
+ if (timr->it.real.interval.tv64 == 0)
+ return;
+
+ timr->it_overrun += (unsigned int) hrtimer_forward(timer,
+ timer->base->get_time(),
+ timr->it.real.interval);
+
+ timr->it_overrun_last = timr->it_overrun;
+ timr->it_overrun = -1;
+ ++timr->it_requeue_pending;
+ 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 do_schedule_next_timer(struct siginfo *info)
+{
+ struct k_itimer *timr;
+ unsigned long flags;
+
+ timr = lock_timer(info->si_tid, &flags);
+
+ if (timr && timr->it_requeue_pending == info->si_sys_private) {
+ if (timr->it_clock < 0)
+ posix_cpu_timer_schedule(timr);
+ else
+ schedule_next_timer(timr);
+
+ info->si_overrun += timr->it_overrun_last;
+ }
+
+ if (timr)
+ unlock_timer(timr, flags);
+}
+
+int posix_timer_event(struct k_itimer *timr, int si_private)
+{
+ struct task_struct *task;
+ int shared, ret = -1;
+ /*
+ * FIXME: if ->sigq is queued we can race with
+ * dequeue_signal()->do_schedule_next_timer().
+ *
+ * If dequeue_signal() sees the "right" value of
+ * si_sys_private it calls do_schedule_next_timer().
+ * We re-queue ->sigq and drop ->it_lock().
+ * do_schedule_next_timer() 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;
+
+ rcu_read_lock();
+ task = pid_task(timr->it_pid, PIDTYPE_PID);
+ if (task) {
+ shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
+ ret = send_sigqueue(timr->sigq, task, shared);
+ }
+ rcu_read_unlock();
+ /* If we failed to send the signal the timer stops. */
+ return ret > 0;
+}
+EXPORT_SYMBOL_GPL(posix_timer_event);
+
+/*
+ * 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);
+
+ if (timr->it.real.interval.tv64 != 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.real.interval.tv64 != 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 = ktime_set(0, NSEC_PER_SEC / HZ);
+
+ if (timr->it.real.interval.tv64 < kj.tv64)
+ now = ktime_add(now, kj);
+ }
+#endif
+ timr->it_overrun += (unsigned int)
+ hrtimer_forward(timer, now,
+ timr->it.real.interval);
+ ret = HRTIMER_RESTART;
+ ++timr->it_requeue_pending;
+ }
+ }
+
+ unlock_timer(timr, flags);
+ return ret;
+}
+
+static struct pid *good_sigevent(sigevent_t * event)
+{
+ struct task_struct *rtn = current->group_leader;
+ int sig = event->sigev_signo;
+
+ if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
+ (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
+ !same_thread_group(rtn, current) ||
+ (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
+ return NULL;
+
+ if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
+ (sig <= 0 || sig > SIGRTMAX || sig_kernel_only(sig) ||
+ sig_kernel_coredump(sig)))
+ return NULL;
+
+ return task_pid(rtn);
+}
+
+void posix_timers_register_clock(const clockid_t clock_id,
+ struct k_clock *new_clock)
+{
+ if ((unsigned) clock_id >= MAX_CLOCKS) {
+ printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
+ clock_id);
+ return;
+ }
+
+ if (!new_clock->clock_get) {
+ printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
+ clock_id);
+ return;
+ }
+ if (!new_clock->clock_getres) {
+ printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
+ clock_id);
+ return;
+ }
+
+ posix_clocks[clock_id] = *new_clock;
+}
+EXPORT_SYMBOL_GPL(posix_timers_register_clock);
+
+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;
+ }
+ memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
+ return tmr;
+}
+
+static void k_itimer_rcu_free(struct rcu_head *head)
+{
+ struct k_itimer *tmr = container_of(head, struct k_itimer, it.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->it.rcu, k_itimer_rcu_free);
+}
+
+static struct k_clock *clockid_to_kclock(const clockid_t id)
+{
+ if (id < 0)
+ return (id & CLOCKFD_MASK) == CLOCKFD ?
+ &clock_posix_dynamic : &clock_posix_cpu;
+
+ if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
+ return NULL;
+ return &posix_clocks[id];
+}
+
+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. */
+
+SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
+ struct sigevent __user *, timer_event_spec,
+ timer_t __user *, created_timer_id)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct k_itimer *new_timer;
+ int error, new_timer_id;
+ sigevent_t event;
+ 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->it_overrun = -1;
+
+ if (timer_event_spec) {
+ if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
+ error = -EFAULT;
+ goto out;
+ }
+ rcu_read_lock();
+ new_timer->it_pid = get_pid(good_sigevent(&event));
+ rcu_read_unlock();
+ if (!new_timer->it_pid) {
+ error = -EINVAL;
+ goto out;
+ }
+ } else {
+ memset(&event.sigev_value, 0, sizeof(event.sigev_value));
+ event.sigev_notify = SIGEV_SIGNAL;
+ event.sigev_signo = SIGALRM;
+ event.sigev_value.sival_int = new_timer->it_id;
+ new_timer->it_pid = get_pid(task_tgid(current));
+ }
+
+ 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;
+ 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;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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.
+ */
+static void
+common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
+{
+ ktime_t now, remaining, iv;
+ struct hrtimer *timer = &timr->it.real.timer;
+
+ memset(cur_setting, 0, sizeof(struct itimerspec));
+
+ iv = timr->it.real.interval;
+
+ /* interval timer ? */
+ if (iv.tv64)
+ cur_setting->it_interval = ktime_to_timespec(iv);
+ else if (!hrtimer_active(timer) &&
+ (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
+ return;
+
+ now = timer->base->get_time();
+
+ /*
+ * 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.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
+ (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
+ timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
+
+ remaining = ktime_sub(hrtimer_get_expires(timer), now);
+ /* Return 0 only, when the timer is expired and not pending */
+ if (remaining.tv64 <= 0) {
+ /*
+ * A single shot SIGEV_NONE timer must return 0, when
+ * it is expired !
+ */
+ if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
+ cur_setting->it_value.tv_nsec = 1;
+ } else
+ cur_setting->it_value = ktime_to_timespec(remaining);
+}
+
+/* Get the time remaining on a POSIX.1b interval timer. */
+SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
+ struct itimerspec __user *, setting)
+{
+ struct itimerspec cur_setting;
+ struct k_itimer *timr;
+ struct k_clock *kc;
+ unsigned long flags;
+ int ret = 0;
+
+ timr = lock_timer(timer_id, &flags);
+ if (!timr)
+ return -EINVAL;
+
+ kc = clockid_to_kclock(timr->it_clock);
+ if (WARN_ON_ONCE(!kc || !kc->timer_get))
+ ret = -EINVAL;
+ else
+ kc->timer_get(timr, &cur_setting);
+
+ unlock_timer(timr, flags);
+
+ if (!ret && copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
+ return -EFAULT;
+
+ return ret;
+}
+
+/*
+ * 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 do_schedule_next_timer(). 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 = timr->it_overrun_last;
+ unlock_timer(timr, flags);
+
+ return overrun;
+}
+
+/*
+ * Protected by RCU!
+ */
+static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr)
+{
+#ifdef CONFIG_PREEMPT_RT_FULL
+ if (kc->timer_set == common_timer_set)
+ hrtimer_wait_for_timer(&timr->it.real.timer);
+ else
+ /* FIXME: Whacky hack for posix-cpu-timers */
+ schedule_timeout(1);
+#endif
+}
+
+/* Set a POSIX.1b interval timer. */
+/* timr->it_lock is taken. */
+static int
+common_timer_set(struct k_itimer *timr, int flags,
+ struct itimerspec *new_setting, struct itimerspec *old_setting)
+{
+ struct hrtimer *timer = &timr->it.real.timer;
+ enum hrtimer_mode mode;
+
+ if (old_setting)
+ common_timer_get(timr, old_setting);
+
+ /* disable the timer */
+ timr->it.real.interval.tv64 = 0;
+ /*
+ * careful here. If smp we could be in the "fire" routine which will
+ * be spinning as we hold the lock. But this is ONLY an SMP issue.
+ */
+ if (hrtimer_try_to_cancel(timer) < 0)
+ return TIMER_RETRY;
+
+ 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;
+
+ mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
+ hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
+ timr->it.real.timer.function = posix_timer_fn;
+
+ hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
+
+ /* Convert interval */
+ timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
+
+ /* SIGEV_NONE timers are not queued ! See common_timer_get */
+ if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
+ /* Setup correct expiry time for relative timers */
+ if (mode == HRTIMER_MODE_REL) {
+ hrtimer_add_expires(timer, timer->base->get_time());
+ }
+ return 0;
+ }
+
+ hrtimer_start_expires(timer, mode);
+ return 0;
+}
+
+/* Set a POSIX.1b interval timer */
+SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
+ const struct itimerspec __user *, new_setting,
+ struct itimerspec __user *, old_setting)
+{
+ struct k_itimer *timr;
+ struct itimerspec new_spec, old_spec;
+ int error = 0;
+ unsigned long flag;
+ struct itimerspec *rtn = old_setting ? &old_spec : NULL;
+ struct k_clock *kc;
+
+ if (!new_setting)
+ return -EINVAL;
+
+ if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
+ return -EFAULT;
+
+ if (!timespec_valid(&new_spec.it_interval) ||
+ !timespec_valid(&new_spec.it_value))
+ return -EINVAL;
+retry:
+ timr = lock_timer(timer_id, &flag);
+ if (!timr)
+ return -EINVAL;
+
+ rcu_read_lock();
+ kc = clockid_to_kclock(timr->it_clock);
+ if (WARN_ON_ONCE(!kc || !kc->timer_set))
+ error = -EINVAL;
+ else
+ error = kc->timer_set(timr, flags, &new_spec, rtn);
+
+ unlock_timer(timr, flag);
+ if (error == TIMER_RETRY) {
+ timer_wait_for_callback(kc, timr);
+ rtn = NULL; // We already got the old time...
+ rcu_read_unlock();
+ goto retry;
+ }
+ rcu_read_unlock();
+
+ if (old_setting && !error &&
+ copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
+ error = -EFAULT;
+
+ return error;
+}
+
+static int common_timer_del(struct k_itimer *timer)
+{
+ timer->it.real.interval.tv64 = 0;
+
+ if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
+ return TIMER_RETRY;
+ return 0;
+}
+
+static inline int timer_delete_hook(struct k_itimer *timer)
+{
+ struct k_clock *kc = clockid_to_kclock(timer->it_clock);
+
+ 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;
+
+retry_delete:
+ timer = lock_timer(timer_id, &flags);
+ if (!timer)
+ return -EINVAL;
+
+ rcu_read_lock();
+ if (timer_delete_hook(timer) == TIMER_RETRY) {
+ unlock_timer(timer, flags);
+ timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
+ timer);
+ rcu_read_unlock();
+ goto retry_delete;
+ }
+ rcu_read_unlock();
+
+ 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;
+}
+
+/*
+ * return timer owned by the process, used by exit_itimers
+ */
+static void itimer_delete(struct k_itimer *timer)
+{
+ unsigned long flags;
+
+retry_delete:
+ spin_lock_irqsave(&timer->it_lock, flags);
+
+ /* On RT we can race with a deletion */
+ if (!timer->it_signal) {
+ unlock_timer(timer, flags);
+ return;
+ }
+
+ if (timer_delete_hook(timer) == TIMER_RETRY) {
+ rcu_read_lock();
+ unlock_timer(timer, flags);
+ timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
+ timer);
+ rcu_read_unlock();
+ goto retry_delete;
+ }
+ list_del(&timer->list);
+ /*
+ * 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);
+}
+
+/*
+ * This is called by do_exit or de_thread, only when there are no more
+ * references to the shared signal_struct.
+ */
+void exit_itimers(struct signal_struct *sig)
+{
+ struct k_itimer *tmr;
+
+ while (!list_empty(&sig->posix_timers)) {
+ tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
+ itimer_delete(tmr);
+ }
+}
+
+SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
+ const struct timespec __user *, tp)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct timespec new_tp;
+
+ if (!kc || !kc->clock_set)
+ return -EINVAL;
+
+ if (copy_from_user(&new_tp, tp, sizeof (*tp)))
+ return -EFAULT;
+
+ return kc->clock_set(which_clock, &new_tp);
+}
+
+SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+ struct timespec __user *,tp)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct timespec kernel_tp;
+ int error;
+
+ if (!kc)
+ return -EINVAL;
+
+ error = kc->clock_get(which_clock, &kernel_tp);
+
+ if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
+ error = -EFAULT;
+
+ return error;
+}
+
+SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
+ struct timex __user *, utx)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct timex ktx;
+ int err;
+
+ if (!kc)
+ return -EINVAL;
+ if (!kc->clock_adj)
+ return -EOPNOTSUPP;
+
+ if (copy_from_user(&ktx, utx, sizeof(ktx)))
+ return -EFAULT;
+
+ err = kc->clock_adj(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 timespec __user *, tp)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct timespec rtn_tp;
+ int error;
+
+ if (!kc)
+ return -EINVAL;
+
+ error = kc->clock_getres(which_clock, &rtn_tp);
+
+ if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp)))
+ error = -EFAULT;
+
+ return error;
+}
+
+/*
+ * nanosleep for monotonic and realtime clocks
+ */
+static int common_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *tsave, struct timespec __user *rmtp)
+{
+ return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
+ HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+ which_clock);
+}
+
+SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
+ const struct timespec __user *, rqtp,
+ struct timespec __user *, rmtp)
+{
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+ struct timespec t;
+
+ if (!kc)
+ return -EINVAL;
+ if (!kc->nsleep)
+ return -ENANOSLEEP_NOTSUP;
+
+ if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
+ return -EFAULT;
+
+ if (!timespec_valid(&t))
+ return -EINVAL;
+
+ return kc->nsleep(which_clock, flags, &t, rmtp);
+}
+
+/*
+ * This will restart clock_nanosleep. This is required only by
+ * compat_clock_nanosleep_restart for now.
+ */
+long clock_nanosleep_restart(struct restart_block *restart_block)
+{
+ clockid_t which_clock = restart_block->nanosleep.clockid;
+ struct k_clock *kc = clockid_to_kclock(which_clock);
+
+ if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))
+ return -EINVAL;
+
+ return kc->nsleep_restart(restart_block);
+}
Code Review / kvmfornfv.git / blobdiff