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-rw-r--r--kernel/posix-timers.c1584
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diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
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+/*
+ * 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/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+
+#include <asm/uaccess.h>
+#include <asm/semaphore.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/compiler.h>
+#include <linux/idr.h>
+#include <linux/posix-timers.h>
+#include <linux/syscalls.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/module.h>
+
+#ifndef div_long_long_rem
+#include <asm/div64.h>
+
+#define div_long_long_rem(dividend,divisor,remainder) ({ \
+ u64 result = dividend; \
+ *remainder = do_div(result,divisor); \
+ result; })
+
+#endif
+#define CLOCK_REALTIME_RES TICK_NSEC /* In nano seconds. */
+
+static inline u64 mpy_l_X_l_ll(unsigned long mpy1,unsigned long mpy2)
+{
+ return (u64)mpy1 * mpy2;
+}
+/*
+ * Management arrays for POSIX timers. Timers are kept in slab memory
+ * Timer ids are allocated by an external routine that keeps track of the
+ * id and the timer. The external interface is:
+ *
+ * void *idr_find(struct idr *idp, int id); to find timer_id <id>
+ * int idr_get_new(struct idr *idp, void *ptr); to get a new id and
+ * related it to <ptr>
+ * void idr_remove(struct idr *idp, int id); to release <id>
+ * void idr_init(struct idr *idp); to initialize <idp>
+ * which we supply.
+ * The idr_get_new *may* call slab for more memory so it must not be
+ * called under a spin lock. Likewise idr_remore may release memory
+ * (but it may be ok to do this under a lock...).
+ * idr_find is just a memory look up and is quite fast. A -1 return
+ * indicates that the requested id does not exist.
+ */
+
+/*
+ * Lets keep our timers in a slab cache :-)
+ */
+static kmem_cache_t *posix_timers_cache;
+static struct idr posix_timers_id;
+static DEFINE_SPINLOCK(idr_lock);
+
+/*
+ * Just because the timer is not in the timer list does NOT mean it is
+ * inactive. It could be in the "fire" routine getting a new expire time.
+ */
+#define TIMER_INACTIVE 1
+
+#ifdef CONFIG_SMP
+# define timer_active(tmr) \
+ ((tmr)->it.real.timer.entry.prev != (void *)TIMER_INACTIVE)
+# define set_timer_inactive(tmr) \
+ do { \
+ (tmr)->it.real.timer.entry.prev = (void *)TIMER_INACTIVE; \
+ } while (0)
+#else
+# define timer_active(tmr) BARFY // error to use outside of SMP
+# define set_timer_inactive(tmr) do { } while (0)
+#endif
+/*
+ * 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 and allows the possibility of adding others. We
+ * provide an interface to add clocks to the table and expect
+ * the "arch" code to add at least one clock that is high
+ * resolution. Here we define the standard CLOCK_REALTIME as a
+ * 1/HZ resolution clock.
+ *
+ * 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. For clocks that use the standard
+ * system timer code these entries should be NULL. This will
+ * allow dispatch without the overhead of indirect function
+ * calls. CLOCKS that depend on other sources (e.g. WWV or GPS)
+ * must supply functions here, even if the function just returns
+ * ENOSYS. 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_process
+ * fields are not modified by timer code.
+ *
+ * At this time all functions EXCEPT clock_nanosleep can be
+ * redirected by the CLOCKS structure. Clock_nanosleep is in
+ * there, but the code ignores it.
+ *
+ * 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];
+/*
+ * We only have one real clock that can be set so we need only one abs list,
+ * even if we should want to have several clocks with differing resolutions.
+ */
+static struct k_clock_abs abs_list = {.list = LIST_HEAD_INIT(abs_list.list),
+ .lock = SPIN_LOCK_UNLOCKED};
+
+static void posix_timer_fn(unsigned long);
+static u64 do_posix_clock_monotonic_gettime_parts(
+ struct timespec *tp, struct timespec *mo);
+int do_posix_clock_monotonic_gettime(struct timespec *tp);
+static int do_posix_clock_monotonic_get(clockid_t, struct timespec *tp);
+
+static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags);
+
+static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
+{
+ spin_unlock_irqrestore(&timr->it_lock, flags);
+}
+
+/*
+ * Call the k_clock hook function if non-null, or the default function.
+ */
+#define CLOCK_DISPATCH(clock, call, arglist) \
+ ((clock) < 0 ? posix_cpu_##call arglist : \
+ (posix_clocks[clock].call != NULL \
+ ? (*posix_clocks[clock].call) arglist : common_##call arglist))
+
+/*
+ * Default clock hook functions when the struct k_clock passed
+ * to register_posix_clock leaves a function pointer null.
+ *
+ * The function common_CALL is the default implementation for
+ * the function pointer CALL in struct k_clock.
+ */
+
+static inline int common_clock_getres(clockid_t which_clock,
+ struct timespec *tp)
+{
+ tp->tv_sec = 0;
+ tp->tv_nsec = posix_clocks[which_clock].res;
+ return 0;
+}
+
+static inline int common_clock_get(clockid_t which_clock, struct timespec *tp)
+{
+ getnstimeofday(tp);
+ return 0;
+}
+
+static inline int common_clock_set(clockid_t which_clock, struct timespec *tp)
+{
+ return do_sys_settimeofday(tp, NULL);
+}
+
+static inline int common_timer_create(struct k_itimer *new_timer)
+{
+ INIT_LIST_HEAD(&new_timer->it.real.abs_timer_entry);
+ init_timer(&new_timer->it.real.timer);
+ new_timer->it.real.timer.data = (unsigned long) new_timer;
+ new_timer->it.real.timer.function = posix_timer_fn;
+ set_timer_inactive(new_timer);
+ return 0;
+}
+
+/*
+ * These ones are defined below.
+ */
+static int common_nsleep(clockid_t, int flags, struct timespec *t);
+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);
+
+/*
+ * Return nonzero iff we know a priori this clockid_t value is bogus.
+ */
+static inline int invalid_clockid(clockid_t which_clock)
+{
+ if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */
+ return 0;
+ if ((unsigned) which_clock >= MAX_CLOCKS)
+ return 1;
+ if (posix_clocks[which_clock].clock_getres != NULL)
+ return 0;
+#ifndef CLOCK_DISPATCH_DIRECT
+ if (posix_clocks[which_clock].res != 0)
+ return 0;
+#endif
+ return 1;
+}
+
+
+/*
+ * Initialize everything, well, just everything in Posix clocks/timers ;)
+ */
+static __init int init_posix_timers(void)
+{
+ struct k_clock clock_realtime = {.res = CLOCK_REALTIME_RES,
+ .abs_struct = &abs_list
+ };
+ struct k_clock clock_monotonic = {.res = CLOCK_REALTIME_RES,
+ .abs_struct = NULL,
+ .clock_get = do_posix_clock_monotonic_get,
+ .clock_set = do_posix_clock_nosettime
+ };
+
+ register_posix_clock(CLOCK_REALTIME, &clock_realtime);
+ register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
+
+ posix_timers_cache = kmem_cache_create("posix_timers_cache",
+ sizeof (struct k_itimer), 0, 0, NULL, NULL);
+ idr_init(&posix_timers_id);
+ return 0;
+}
+
+__initcall(init_posix_timers);
+
+static void tstojiffie(struct timespec *tp, int res, u64 *jiff)
+{
+ long sec = tp->tv_sec;
+ long nsec = tp->tv_nsec + res - 1;
+
+ if (nsec > NSEC_PER_SEC) {
+ sec++;
+ nsec -= NSEC_PER_SEC;
+ }
+
+ /*
+ * The scaling constants are defined in <linux/time.h>
+ * The difference between there and here is that we do the
+ * res rounding and compute a 64-bit result (well so does that
+ * but it then throws away the high bits).
+ */
+ *jiff = (mpy_l_X_l_ll(sec, SEC_CONVERSION) +
+ (mpy_l_X_l_ll(nsec, NSEC_CONVERSION) >>
+ (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
+}
+
+/*
+ * This function adjusts the timer as needed as a result of the clock
+ * being set. It should only be called for absolute timers, and then
+ * under the abs_list lock. It computes the time difference and sets
+ * the new jiffies value in the timer. It also updates the timers
+ * reference wall_to_monotonic value. It is complicated by the fact
+ * that tstojiffies() only handles positive times and it needs to work
+ * with both positive and negative times. Also, for negative offsets,
+ * we need to defeat the res round up.
+ *
+ * Return is true if there is a new time, else false.
+ */
+static long add_clockset_delta(struct k_itimer *timr,
+ struct timespec *new_wall_to)
+{
+ struct timespec delta;
+ int sign = 0;
+ u64 exp;
+
+ set_normalized_timespec(&delta,
+ new_wall_to->tv_sec -
+ timr->it.real.wall_to_prev.tv_sec,
+ new_wall_to->tv_nsec -
+ timr->it.real.wall_to_prev.tv_nsec);
+ if (likely(!(delta.tv_sec | delta.tv_nsec)))
+ return 0;
+ if (delta.tv_sec < 0) {
+ set_normalized_timespec(&delta,
+ -delta.tv_sec,
+ 1 - delta.tv_nsec -
+ posix_clocks[timr->it_clock].res);
+ sign++;
+ }
+ tstojiffie(&delta, posix_clocks[timr->it_clock].res, &exp);
+ timr->it.real.wall_to_prev = *new_wall_to;
+ timr->it.real.timer.expires += (sign ? -exp : exp);
+ return 1;
+}
+
+static void remove_from_abslist(struct k_itimer *timr)
+{
+ if (!list_empty(&timr->it.real.abs_timer_entry)) {
+ spin_lock(&abs_list.lock);
+ list_del_init(&timr->it.real.abs_timer_entry);
+ spin_unlock(&abs_list.lock);
+ }
+}
+
+static void schedule_next_timer(struct k_itimer *timr)
+{
+ struct timespec new_wall_to;
+ struct now_struct now;
+ unsigned long seq;
+
+ /*
+ * Set up the timer for the next interval (if there is one).
+ * Note: this code uses the abs_timer_lock to protect
+ * it.real.wall_to_prev and must hold it until exp is set, not exactly
+ * obvious...
+
+ * This function is used for CLOCK_REALTIME* and
+ * CLOCK_MONOTONIC* timers. If we ever want to handle other
+ * CLOCKs, the calling code (do_schedule_next_timer) would need
+ * to pull the "clock" info from the timer and dispatch the
+ * "other" CLOCKs "next timer" code (which, I suppose should
+ * also be added to the k_clock structure).
+ */
+ if (!timr->it.real.incr)
+ return;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ new_wall_to = wall_to_monotonic;
+ posix_get_now(&now);
+ } while (read_seqretry(&xtime_lock, seq));
+
+ if (!list_empty(&timr->it.real.abs_timer_entry)) {
+ spin_lock(&abs_list.lock);
+ add_clockset_delta(timr, &new_wall_to);
+
+ posix_bump_timer(timr, now);
+
+ spin_unlock(&abs_list.lock);
+ } else {
+ posix_bump_timer(timr, now);
+ }
+ timr->it_overrun_last = timr->it_overrun;
+ timr->it_overrun = -1;
+ ++timr->it_requeue_pending;
+ add_timer(&timr->it.real.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 aginst 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)
+ goto exit;
+
+ if (timr->it_clock < 0) /* CPU clock */
+ posix_cpu_timer_schedule(timr);
+ else
+ schedule_next_timer(timr);
+ info->si_overrun = timr->it_overrun_last;
+exit:
+ if (timr)
+ unlock_timer(timr, flags);
+}
+
+int posix_timer_event(struct k_itimer *timr,int si_private)
+{
+ memset(&timr->sigq->info, 0, sizeof(siginfo_t));
+ timr->sigq->info.si_sys_private = si_private;
+ /*
+ * Send signal to the process that owns this timer.
+
+ * This code assumes that all the possible abs_lists share the
+ * same lock (there is only one list at this time). If this is
+ * not the case, the CLOCK info would need to be used to find
+ * the proper abs list lock.
+ */
+
+ timr->sigq->info.si_signo = timr->it_sigev_signo;
+ timr->sigq->info.si_errno = 0;
+ timr->sigq->info.si_code = SI_TIMER;
+ timr->sigq->info.si_tid = timr->it_id;
+ timr->sigq->info.si_value = timr->it_sigev_value;
+ if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
+ if (unlikely(timr->it_process->flags & PF_EXITING)) {
+ timr->it_sigev_notify = SIGEV_SIGNAL;
+ put_task_struct(timr->it_process);
+ timr->it_process = timr->it_process->group_leader;
+ goto group;
+ }
+ return send_sigqueue(timr->it_sigev_signo, timr->sigq,
+ timr->it_process);
+ }
+ else {
+ group:
+ return send_group_sigqueue(timr->it_sigev_signo, timr->sigq,
+ timr->it_process);
+ }
+}
+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 void posix_timer_fn(unsigned long __data)
+{
+ struct k_itimer *timr = (struct k_itimer *) __data;
+ unsigned long flags;
+ unsigned long seq;
+ struct timespec delta, new_wall_to;
+ u64 exp = 0;
+ int do_notify = 1;
+
+ spin_lock_irqsave(&timr->it_lock, flags);
+ set_timer_inactive(timr);
+ if (!list_empty(&timr->it.real.abs_timer_entry)) {
+ spin_lock(&abs_list.lock);
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ new_wall_to = wall_to_monotonic;
+ } while (read_seqretry(&xtime_lock, seq));
+ set_normalized_timespec(&delta,
+ new_wall_to.tv_sec -
+ timr->it.real.wall_to_prev.tv_sec,
+ new_wall_to.tv_nsec -
+ timr->it.real.wall_to_prev.tv_nsec);
+ if (likely((delta.tv_sec | delta.tv_nsec ) == 0)) {
+ /* do nothing, timer is on time */
+ } else if (delta.tv_sec < 0) {
+ /* do nothing, timer is already late */
+ } else {
+ /* timer is early due to a clock set */
+ tstojiffie(&delta,
+ posix_clocks[timr->it_clock].res,
+ &exp);
+ timr->it.real.wall_to_prev = new_wall_to;
+ timr->it.real.timer.expires += exp;
+ add_timer(&timr->it.real.timer);
+ do_notify = 0;
+ }
+ spin_unlock(&abs_list.lock);
+
+ }
+ if (do_notify) {
+ int si_private=0;
+
+ if (timr->it.real.incr)
+ si_private = ++timr->it_requeue_pending;
+ else {
+ remove_from_abslist(timr);
+ }
+
+ 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.
+ */
+ schedule_next_timer(timr);
+ }
+ unlock_timer(timr, flags); /* hold thru abs lock to keep irq off */
+}
+
+
+static inline struct task_struct * good_sigevent(sigevent_t * event)
+{
+ struct task_struct *rtn = current->group_leader;
+
+ if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
+ (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) ||
+ rtn->tgid != current->tgid ||
+ (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
+ return NULL;
+
+ if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
+ ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
+ return NULL;
+
+ return rtn;
+}
+
+void register_posix_clock(clockid_t clock_id, struct k_clock *new_clock)
+{
+ if ((unsigned) clock_id >= MAX_CLOCKS) {
+ printk("POSIX clock register failed for clock_id %d\n",
+ clock_id);
+ return;
+ }
+
+ posix_clocks[clock_id] = *new_clock;
+}
+EXPORT_SYMBOL_GPL(register_posix_clock);
+
+static struct k_itimer * alloc_posix_timer(void)
+{
+ struct k_itimer *tmr;
+ tmr = kmem_cache_alloc(posix_timers_cache, GFP_KERNEL);
+ if (!tmr)
+ return tmr;
+ memset(tmr, 0, sizeof (struct k_itimer));
+ if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
+ kmem_cache_free(posix_timers_cache, tmr);
+ tmr = NULL;
+ }
+ return 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(&idr_lock, flags);
+ idr_remove(&posix_timers_id, tmr->it_id);
+ spin_unlock_irqrestore(&idr_lock, flags);
+ }
+ sigqueue_free(tmr->sigq);
+ if (unlikely(tmr->it_process) &&
+ tmr->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+ put_task_struct(tmr->it_process);
+ kmem_cache_free(posix_timers_cache, tmr);
+}
+
+/* Create a POSIX.1b interval timer. */
+
+asmlinkage long
+sys_timer_create(clockid_t which_clock,
+ struct sigevent __user *timer_event_spec,
+ timer_t __user * created_timer_id)
+{
+ int error = 0;
+ struct k_itimer *new_timer = NULL;
+ int new_timer_id;
+ struct task_struct *process = NULL;
+ unsigned long flags;
+ sigevent_t event;
+ int it_id_set = IT_ID_NOT_SET;
+
+ if (invalid_clockid(which_clock))
+ return -EINVAL;
+
+ new_timer = alloc_posix_timer();
+ if (unlikely(!new_timer))
+ return -EAGAIN;
+
+ spin_lock_init(&new_timer->it_lock);
+ retry:
+ if (unlikely(!idr_pre_get(&posix_timers_id, GFP_KERNEL))) {
+ error = -EAGAIN;
+ goto out;
+ }
+ spin_lock_irq(&idr_lock);
+ error = idr_get_new(&posix_timers_id,
+ (void *) new_timer,
+ &new_timer_id);
+ spin_unlock_irq(&idr_lock);
+ if (error == -EAGAIN)
+ goto retry;
+ else if (error) {
+ /*
+ * Wierd looking, but we return EAGAIN if the IDR is
+ * full (proper POSIX return value for this)
+ */
+ error = -EAGAIN;
+ 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;
+ error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
+ if (error)
+ goto out;
+
+ /*
+ * return the timer_id now. The next step is hard to
+ * back out if there is an error.
+ */
+ if (copy_to_user(created_timer_id,
+ &new_timer_id, sizeof (new_timer_id))) {
+ error = -EFAULT;
+ goto out;
+ }
+ if (timer_event_spec) {
+ if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
+ error = -EFAULT;
+ goto out;
+ }
+ new_timer->it_sigev_notify = event.sigev_notify;
+ new_timer->it_sigev_signo = event.sigev_signo;
+ new_timer->it_sigev_value = event.sigev_value;
+
+ read_lock(&tasklist_lock);
+ if ((process = good_sigevent(&event))) {
+ /*
+ * We may be setting up this process for another
+ * thread. It may be exiting. To catch this
+ * case the we check the PF_EXITING flag. If
+ * the flag is not set, the siglock will catch
+ * him before it is too late (in exit_itimers).
+ *
+ * The exec case is a bit more invloved but easy
+ * to code. If the process is in our thread
+ * group (and it must be or we would not allow
+ * it here) and is doing an exec, it will cause
+ * us to be killed. In this case it will wait
+ * for us to die which means we can finish this
+ * linkage with our last gasp. I.e. no code :)
+ */
+ spin_lock_irqsave(&process->sighand->siglock, flags);
+ if (!(process->flags & PF_EXITING)) {
+ new_timer->it_process = process;
+ list_add(&new_timer->list,
+ &process->signal->posix_timers);
+ spin_unlock_irqrestore(&process->sighand->siglock, flags);
+ if (new_timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+ get_task_struct(process);
+ } else {
+ spin_unlock_irqrestore(&process->sighand->siglock, flags);
+ process = NULL;
+ }
+ }
+ read_unlock(&tasklist_lock);
+ if (!process) {
+ error = -EINVAL;
+ goto out;
+ }
+ } else {
+ new_timer->it_sigev_notify = SIGEV_SIGNAL;
+ new_timer->it_sigev_signo = SIGALRM;
+ new_timer->it_sigev_value.sival_int = new_timer->it_id;
+ process = current->group_leader;
+ spin_lock_irqsave(&process->sighand->siglock, flags);
+ new_timer->it_process = process;
+ list_add(&new_timer->list, &process->signal->posix_timers);
+ spin_unlock_irqrestore(&process->sighand->siglock, flags);
+ }
+
+ /*
+ * 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:
+ if (error)
+ release_posix_timer(new_timer, it_id_set);
+
+ return error;
+}
+
+/*
+ * good_timespec
+ *
+ * This function checks the elements of a timespec structure.
+ *
+ * Arguments:
+ * ts : Pointer to the timespec structure to check
+ *
+ * Return value:
+ * If a NULL pointer was passed in, or the tv_nsec field was less than 0
+ * or greater than NSEC_PER_SEC, or the tv_sec field was less than 0,
+ * this function returns 0. Otherwise it returns 1.
+ */
+static int good_timespec(const struct timespec *ts)
+{
+ if ((!ts) || (ts->tv_sec < 0) ||
+ ((unsigned) ts->tv_nsec >= NSEC_PER_SEC))
+ return 0;
+ return 1;
+}
+
+/*
+ * 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;
+ /*
+ * Watch out here. We do a irqsave on the idr_lock and pass the
+ * flags part over to the timer lock. Must not let interrupts in
+ * while we are moving the lock.
+ */
+
+ spin_lock_irqsave(&idr_lock, *flags);
+ timr = (struct k_itimer *) idr_find(&posix_timers_id, (int) timer_id);
+ if (timr) {
+ spin_lock(&timr->it_lock);
+ spin_unlock(&idr_lock);
+
+ if ((timr->it_id != timer_id) || !(timr->it_process) ||
+ timr->it_process->tgid != current->tgid) {
+ unlock_timer(timr, *flags);
+ timr = NULL;
+ }
+ } else
+ spin_unlock_irqrestore(&idr_lock, *flags);
+
+ return timr;
+}
+
+/*
+ * 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)
+{
+ unsigned long expires;
+ struct now_struct now;
+
+ do
+ expires = timr->it.real.timer.expires;
+ while ((volatile long) (timr->it.real.timer.expires) != expires);
+
+ posix_get_now(&now);
+
+ if (expires &&
+ ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) &&
+ !timr->it.real.incr &&
+ posix_time_before(&timr->it.real.timer, &now))
+ timr->it.real.timer.expires = expires = 0;
+ if (expires) {
+ if (timr->it_requeue_pending & REQUEUE_PENDING ||
+ (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
+ posix_bump_timer(timr, now);
+ expires = timr->it.real.timer.expires;
+ }
+ else
+ if (!timer_pending(&timr->it.real.timer))
+ expires = 0;
+ if (expires)
+ expires -= now.jiffies;
+ }
+ jiffies_to_timespec(expires, &cur_setting->it_value);
+ jiffies_to_timespec(timr->it.real.incr, &cur_setting->it_interval);
+
+ if (cur_setting->it_value.tv_sec < 0) {
+ cur_setting->it_value.tv_nsec = 1;
+ cur_setting->it_value.tv_sec = 0;
+ }
+}
+
+/* Get the time remaining on a POSIX.1b interval timer. */
+asmlinkage long
+sys_timer_gettime(timer_t timer_id, struct itimerspec __user *setting)
+{
+ struct k_itimer *timr;
+ struct itimerspec cur_setting;
+ unsigned long flags;
+
+ timr = lock_timer(timer_id, &flags);
+ if (!timr)
+ return -EINVAL;
+
+ CLOCK_DISPATCH(timr->it_clock, timer_get, (timr, &cur_setting));
+
+ unlock_timer(timr, flags);
+
+ if (copy_to_user(setting, &cur_setting, sizeof (cur_setting)))
+ return -EFAULT;
+
+ return 0;
+}
+/*
+ * 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.
+ */
+
+asmlinkage long
+sys_timer_getoverrun(timer_t timer_id)
+{
+ struct k_itimer *timr;
+ int overrun;
+ long flags;
+
+ timr = lock_timer(timer_id, &flags);
+ if (!timr)
+ return -EINVAL;
+
+ overrun = timr->it_overrun_last;
+ unlock_timer(timr, flags);
+
+ return overrun;
+}
+/*
+ * Adjust for absolute time
+ *
+ * If absolute time is given and it is not CLOCK_MONOTONIC, we need to
+ * adjust for the offset between the timer clock (CLOCK_MONOTONIC) and
+ * what ever clock he is using.
+ *
+ * If it is relative time, we need to add the current (CLOCK_MONOTONIC)
+ * time to it to get the proper time for the timer.
+ */
+static int adjust_abs_time(struct k_clock *clock, struct timespec *tp,
+ int abs, u64 *exp, struct timespec *wall_to)
+{
+ struct timespec now;
+ struct timespec oc = *tp;
+ u64 jiffies_64_f;
+ int rtn =0;
+
+ if (abs) {
+ /*
+ * The mask pick up the 4 basic clocks
+ */
+ if (!((clock - &posix_clocks[0]) & ~CLOCKS_MASK)) {
+ jiffies_64_f = do_posix_clock_monotonic_gettime_parts(
+ &now, wall_to);
+ /*
+ * If we are doing a MONOTONIC clock
+ */
+ if((clock - &posix_clocks[0]) & CLOCKS_MONO){
+ now.tv_sec += wall_to->tv_sec;
+ now.tv_nsec += wall_to->tv_nsec;
+ }
+ } else {
+ /*
+ * Not one of the basic clocks
+ */
+ clock->clock_get(clock - posix_clocks, &now);
+ jiffies_64_f = get_jiffies_64();
+ }
+ /*
+ * Take away now to get delta
+ */
+ oc.tv_sec -= now.tv_sec;
+ oc.tv_nsec -= now.tv_nsec;
+ /*
+ * Normalize...
+ */
+ while ((oc.tv_nsec - NSEC_PER_SEC) >= 0) {
+ oc.tv_nsec -= NSEC_PER_SEC;
+ oc.tv_sec++;
+ }
+ while ((oc.tv_nsec) < 0) {
+ oc.tv_nsec += NSEC_PER_SEC;
+ oc.tv_sec--;
+ }
+ }else{
+ jiffies_64_f = get_jiffies_64();
+ }
+ /*
+ * Check if the requested time is prior to now (if so set now)
+ */
+ if (oc.tv_sec < 0)
+ oc.tv_sec = oc.tv_nsec = 0;
+
+ if (oc.tv_sec | oc.tv_nsec)
+ set_normalized_timespec(&oc, oc.tv_sec,
+ oc.tv_nsec + clock->res);
+ tstojiffie(&oc, clock->res, exp);
+
+ /*
+ * Check if the requested time is more than the timer code
+ * can handle (if so we error out but return the value too).
+ */
+ if (*exp > ((u64)MAX_JIFFY_OFFSET))
+ /*
+ * This is a considered response, not exactly in
+ * line with the standard (in fact it is silent on
+ * possible overflows). We assume such a large
+ * value is ALMOST always a programming error and
+ * try not to compound it by setting a really dumb
+ * value.
+ */
+ rtn = -EINVAL;
+ /*
+ * return the actual jiffies expire time, full 64 bits
+ */
+ *exp += jiffies_64_f;
+ return rtn;
+}
+
+/* Set a POSIX.1b interval timer. */
+/* timr->it_lock is taken. */
+static inline int
+common_timer_set(struct k_itimer *timr, int flags,
+ struct itimerspec *new_setting, struct itimerspec *old_setting)
+{
+ struct k_clock *clock = &posix_clocks[timr->it_clock];
+ u64 expire_64;
+
+ if (old_setting)
+ common_timer_get(timr, old_setting);
+
+ /* disable the timer */
+ timr->it.real.incr = 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.
+ */
+#ifdef CONFIG_SMP
+ if (timer_active(timr) && !del_timer(&timr->it.real.timer))
+ /*
+ * It can only be active if on an other cpu. Since
+ * we have cleared the interval stuff above, it should
+ * clear once we release the spin lock. Of course once
+ * we do that anything could happen, including the
+ * complete melt down of the timer. So return with
+ * a "retry" exit status.
+ */
+ return TIMER_RETRY;
+
+ set_timer_inactive(timr);
+#else
+ del_timer(&timr->it.real.timer);
+#endif
+ remove_from_abslist(timr);
+
+ timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
+ ~REQUEUE_PENDING;
+ timr->it_overrun_last = 0;
+ timr->it_overrun = -1;
+ /*
+ *switch off the timer when it_value is zero
+ */
+ if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec) {
+ timr->it.real.timer.expires = 0;
+ return 0;
+ }
+
+ if (adjust_abs_time(clock,
+ &new_setting->it_value, flags & TIMER_ABSTIME,
+ &expire_64, &(timr->it.real.wall_to_prev))) {
+ return -EINVAL;
+ }
+ timr->it.real.timer.expires = (unsigned long)expire_64;
+ tstojiffie(&new_setting->it_interval, clock->res, &expire_64);
+ timr->it.real.incr = (unsigned long)expire_64;
+
+ /*
+ * We do not even queue SIGEV_NONE timers! But we do put them
+ * in the abs list so we can do that right.
+ */
+ if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE))
+ add_timer(&timr->it.real.timer);
+
+ if (flags & TIMER_ABSTIME && clock->abs_struct) {
+ spin_lock(&clock->abs_struct->lock);
+ list_add_tail(&(timr->it.real.abs_timer_entry),
+ &(clock->abs_struct->list));
+ spin_unlock(&clock->abs_struct->lock);
+ }
+ return 0;
+}
+
+/* Set a POSIX.1b interval timer */
+asmlinkage long
+sys_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;
+ long flag;
+ struct itimerspec *rtn = old_setting ? &old_spec : NULL;
+
+ if (!new_setting)
+ return -EINVAL;
+
+ if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
+ return -EFAULT;
+
+ if ((!good_timespec(&new_spec.it_interval)) ||
+ (!good_timespec(&new_spec.it_value)))
+ return -EINVAL;
+retry:
+ timr = lock_timer(timer_id, &flag);
+ if (!timr)
+ return -EINVAL;
+
+ error = CLOCK_DISPATCH(timr->it_clock, timer_set,
+ (timr, flags, &new_spec, rtn));
+
+ unlock_timer(timr, flag);
+ if (error == TIMER_RETRY) {
+ rtn = NULL; // We already got the old time...
+ goto retry;
+ }
+
+ if (old_setting && !error && copy_to_user(old_setting,
+ &old_spec, sizeof (old_spec)))
+ error = -EFAULT;
+
+ return error;
+}
+
+static inline int common_timer_del(struct k_itimer *timer)
+{
+ timer->it.real.incr = 0;
+#ifdef CONFIG_SMP
+ if (timer_active(timer) && !del_timer(&timer->it.real.timer))
+ /*
+ * It can only be active if on an other cpu. Since
+ * we have cleared the interval stuff above, it should
+ * clear once we release the spin lock. Of course once
+ * we do that anything could happen, including the
+ * complete melt down of the timer. So return with
+ * a "retry" exit status.
+ */
+ return TIMER_RETRY;
+#else
+ del_timer(&timer->it.real.timer);
+#endif
+ remove_from_abslist(timer);
+
+ return 0;
+}
+
+static inline int timer_delete_hook(struct k_itimer *timer)
+{
+ return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer));
+}
+
+/* Delete a POSIX.1b interval timer. */
+asmlinkage long
+sys_timer_delete(timer_t timer_id)
+{
+ struct k_itimer *timer;
+ long flags;
+
+#ifdef CONFIG_SMP
+ int error;
+retry_delete:
+#endif
+ timer = lock_timer(timer_id, &flags);
+ if (!timer)
+ return -EINVAL;
+
+#ifdef CONFIG_SMP
+ error = timer_delete_hook(timer);
+
+ if (error == TIMER_RETRY) {
+ unlock_timer(timer, flags);
+ goto retry_delete;
+ }
+#else
+ timer_delete_hook(timer);
+#endif
+ 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).
+ */
+ if (timer->it_process) {
+ if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+ put_task_struct(timer->it_process);
+ timer->it_process = 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 inline void itimer_delete(struct k_itimer *timer)
+{
+ unsigned long flags;
+
+#ifdef CONFIG_SMP
+ int error;
+retry_delete:
+#endif
+ spin_lock_irqsave(&timer->it_lock, flags);
+
+#ifdef CONFIG_SMP
+ error = timer_delete_hook(timer);
+
+ if (error == TIMER_RETRY) {
+ unlock_timer(timer, flags);
+ goto retry_delete;
+ }
+#else
+ timer_delete_hook(timer);
+#endif
+ list_del(&timer->list);
+ /*
+ * This keeps any tasks waiting on the spin lock from thinking
+ * they got something (see the lock code above).
+ */
+ if (timer->it_process) {
+ if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+ put_task_struct(timer->it_process);
+ timer->it_process = NULL;
+ }
+ unlock_timer(timer, flags);
+ release_posix_timer(timer, IT_ID_SET);
+}
+
+/*
+ * This is called by __exit_signal, 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);
+ }
+}
+
+/*
+ * And now for the "clock" calls
+ *
+ * These functions are called both from timer functions (with the timer
+ * spin_lock_irq() held and from clock calls with no locking. They must
+ * use the save flags versions of locks.
+ */
+
+/*
+ * We do ticks here to avoid the irq lock ( they take sooo long).
+ * The seqlock is great here. Since we a reader, we don't really care
+ * if we are interrupted since we don't take lock that will stall us or
+ * any other cpu. Voila, no irq lock is needed.
+ *
+ */
+
+static u64 do_posix_clock_monotonic_gettime_parts(
+ struct timespec *tp, struct timespec *mo)
+{
+ u64 jiff;
+ unsigned int seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ getnstimeofday(tp);
+ *mo = wall_to_monotonic;
+ jiff = jiffies_64;
+
+ } while(read_seqretry(&xtime_lock, seq));
+
+ return jiff;
+}
+
+static int do_posix_clock_monotonic_get(clockid_t clock, struct timespec *tp)
+{
+ struct timespec wall_to_mono;
+
+ do_posix_clock_monotonic_gettime_parts(tp, &wall_to_mono);
+
+ tp->tv_sec += wall_to_mono.tv_sec;
+ tp->tv_nsec += wall_to_mono.tv_nsec;
+
+ if ((tp->tv_nsec - NSEC_PER_SEC) > 0) {
+ tp->tv_nsec -= NSEC_PER_SEC;
+ tp->tv_sec++;
+ }
+ return 0;
+}
+
+int do_posix_clock_monotonic_gettime(struct timespec *tp)
+{
+ return do_posix_clock_monotonic_get(CLOCK_MONOTONIC, tp);
+}
+
+int do_posix_clock_nosettime(clockid_t clockid, struct timespec *tp)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(do_posix_clock_nosettime);
+
+int do_posix_clock_notimer_create(struct k_itimer *timer)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(do_posix_clock_notimer_create);
+
+int do_posix_clock_nonanosleep(clockid_t clock, int flags, struct timespec *t)
+{
+#ifndef ENOTSUP
+ return -EOPNOTSUPP; /* aka ENOTSUP in userland for POSIX */
+#else /* parisc does define it separately. */
+ return -ENOTSUP;
+#endif
+}
+EXPORT_SYMBOL_GPL(do_posix_clock_nonanosleep);
+
+asmlinkage long
+sys_clock_settime(clockid_t which_clock, const struct timespec __user *tp)
+{
+ struct timespec new_tp;
+
+ if (invalid_clockid(which_clock))
+ return -EINVAL;
+ if (copy_from_user(&new_tp, tp, sizeof (*tp)))
+ return -EFAULT;
+
+ return CLOCK_DISPATCH(which_clock, clock_set, (which_clock, &new_tp));
+}
+
+asmlinkage long
+sys_clock_gettime(clockid_t which_clock, struct timespec __user *tp)
+{
+ struct timespec kernel_tp;
+ int error;
+
+ if (invalid_clockid(which_clock))
+ return -EINVAL;
+ error = CLOCK_DISPATCH(which_clock, clock_get,
+ (which_clock, &kernel_tp));
+ if (!error && copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
+ error = -EFAULT;
+
+ return error;
+
+}
+
+asmlinkage long
+sys_clock_getres(clockid_t which_clock, struct timespec __user *tp)
+{
+ struct timespec rtn_tp;
+ int error;
+
+ if (invalid_clockid(which_clock))
+ return -EINVAL;
+
+ error = CLOCK_DISPATCH(which_clock, clock_getres,
+ (which_clock, &rtn_tp));
+
+ if (!error && tp && copy_to_user(tp, &rtn_tp, sizeof (rtn_tp))) {
+ error = -EFAULT;
+ }
+
+ return error;
+}
+
+static void nanosleep_wake_up(unsigned long __data)
+{
+ struct task_struct *p = (struct task_struct *) __data;
+
+ wake_up_process(p);
+}
+
+/*
+ * The standard says that an absolute nanosleep call MUST wake up at
+ * the requested time in spite of clock settings. Here is what we do:
+ * For each nanosleep call that needs it (only absolute and not on
+ * CLOCK_MONOTONIC* (as it can not be set)) we thread a little structure
+ * into the "nanosleep_abs_list". All we need is the task_struct pointer.
+ * When ever the clock is set we just wake up all those tasks. The rest
+ * is done by the while loop in clock_nanosleep().
+ *
+ * On locking, clock_was_set() is called from update_wall_clock which
+ * holds (or has held for it) a write_lock_irq( xtime_lock) and is
+ * called from the timer bh code. Thus we need the irq save locks.
+ *
+ * Also, on the call from update_wall_clock, that is done as part of a
+ * softirq thing. We don't want to delay the system that much (possibly
+ * long list of timers to fix), so we defer that work to keventd.
+ */
+
+static DECLARE_WAIT_QUEUE_HEAD(nanosleep_abs_wqueue);
+static DECLARE_WORK(clock_was_set_work, (void(*)(void*))clock_was_set, NULL);
+
+static DECLARE_MUTEX(clock_was_set_lock);
+
+void clock_was_set(void)
+{
+ struct k_itimer *timr;
+ struct timespec new_wall_to;
+ LIST_HEAD(cws_list);
+ unsigned long seq;
+
+
+ if (unlikely(in_interrupt())) {
+ schedule_work(&clock_was_set_work);
+ return;
+ }
+ wake_up_all(&nanosleep_abs_wqueue);
+
+ /*
+ * Check if there exist TIMER_ABSTIME timers to correct.
+ *
+ * Notes on locking: This code is run in task context with irq
+ * on. We CAN be interrupted! All other usage of the abs list
+ * lock is under the timer lock which holds the irq lock as
+ * well. We REALLY don't want to scan the whole list with the
+ * interrupt system off, AND we would like a sequence lock on
+ * this code as well. Since we assume that the clock will not
+ * be set often, it seems ok to take and release the irq lock
+ * for each timer. In fact add_timer will do this, so this is
+ * not an issue. So we know when we are done, we will move the
+ * whole list to a new location. Then as we process each entry,
+ * we will move it to the actual list again. This way, when our
+ * copy is empty, we are done. We are not all that concerned
+ * about preemption so we will use a semaphore lock to protect
+ * aginst reentry. This way we will not stall another
+ * processor. It is possible that this may delay some timers
+ * that should have expired, given the new clock, but even this
+ * will be minimal as we will always update to the current time,
+ * even if it was set by a task that is waiting for entry to
+ * this code. Timers that expire too early will be caught by
+ * the expire code and restarted.
+
+ * Absolute timers that repeat are left in the abs list while
+ * waiting for the task to pick up the signal. This means we
+ * may find timers that are not in the "add_timer" list, but are
+ * in the abs list. We do the same thing for these, save
+ * putting them back in the "add_timer" list. (Note, these are
+ * left in the abs list mainly to indicate that they are
+ * ABSOLUTE timers, a fact that is used by the re-arm code, and
+ * for which we have no other flag.)
+
+ */
+
+ down(&clock_was_set_lock);
+ spin_lock_irq(&abs_list.lock);
+ list_splice_init(&abs_list.list, &cws_list);
+ spin_unlock_irq(&abs_list.lock);
+ do {
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ new_wall_to = wall_to_monotonic;
+ } while (read_seqretry(&xtime_lock, seq));
+
+ spin_lock_irq(&abs_list.lock);
+ if (list_empty(&cws_list)) {
+ spin_unlock_irq(&abs_list.lock);
+ break;
+ }
+ timr = list_entry(cws_list.next, struct k_itimer,
+ it.real.abs_timer_entry);
+
+ list_del_init(&timr->it.real.abs_timer_entry);
+ if (add_clockset_delta(timr, &new_wall_to) &&
+ del_timer(&timr->it.real.timer)) /* timer run yet? */
+ add_timer(&timr->it.real.timer);
+ list_add(&timr->it.real.abs_timer_entry, &abs_list.list);
+ spin_unlock_irq(&abs_list.lock);
+ } while (1);
+
+ up(&clock_was_set_lock);
+}
+
+long clock_nanosleep_restart(struct restart_block *restart_block);
+
+asmlinkage long
+sys_clock_nanosleep(clockid_t which_clock, int flags,
+ const struct timespec __user *rqtp,
+ struct timespec __user *rmtp)
+{
+ struct timespec t;
+ struct restart_block *restart_block =
+ &(current_thread_info()->restart_block);
+ int ret;
+
+ if (invalid_clockid(which_clock))
+ return -EINVAL;
+
+ if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
+ return -EFAULT;
+
+ if ((unsigned) t.tv_nsec >= NSEC_PER_SEC || t.tv_sec < 0)
+ return -EINVAL;
+
+ /*
+ * Do this here as nsleep function does not have the real address.
+ */
+ restart_block->arg1 = (unsigned long)rmtp;
+
+ ret = CLOCK_DISPATCH(which_clock, nsleep, (which_clock, flags, &t));
+
+ if ((ret == -ERESTART_RESTARTBLOCK) && rmtp &&
+ copy_to_user(rmtp, &t, sizeof (t)))
+ return -EFAULT;
+ return ret;
+}
+
+
+static int common_nsleep(clockid_t which_clock,
+ int flags, struct timespec *tsave)
+{
+ struct timespec t, dum;
+ struct timer_list new_timer;
+ DECLARE_WAITQUEUE(abs_wqueue, current);
+ u64 rq_time = (u64)0;
+ s64 left;
+ int abs;
+ struct restart_block *restart_block =
+ &current_thread_info()->restart_block;
+
+ abs_wqueue.flags = 0;
+ init_timer(&new_timer);
+ new_timer.expires = 0;
+ new_timer.data = (unsigned long) current;
+ new_timer.function = nanosleep_wake_up;
+ abs = flags & TIMER_ABSTIME;
+
+ if (restart_block->fn == clock_nanosleep_restart) {
+ /*
+ * Interrupted by a non-delivered signal, pick up remaining
+ * time and continue. Remaining time is in arg2 & 3.
+ */
+ restart_block->fn = do_no_restart_syscall;
+
+ rq_time = restart_block->arg3;
+ rq_time = (rq_time << 32) + restart_block->arg2;
+ if (!rq_time)
+ return -EINTR;
+ left = rq_time - get_jiffies_64();
+ if (left <= (s64)0)
+ return 0; /* Already passed */
+ }
+
+ if (abs && (posix_clocks[which_clock].clock_get !=
+ posix_clocks[CLOCK_MONOTONIC].clock_get))
+ add_wait_queue(&nanosleep_abs_wqueue, &abs_wqueue);
+
+ do {
+ t = *tsave;
+ if (abs || !rq_time) {
+ adjust_abs_time(&posix_clocks[which_clock], &t, abs,
+ &rq_time, &dum);
+ }
+
+ left = rq_time - get_jiffies_64();
+ if (left >= (s64)MAX_JIFFY_OFFSET)
+ left = (s64)MAX_JIFFY_OFFSET;
+ if (left < (s64)0)
+ break;
+
+ new_timer.expires = jiffies + left;
+ __set_current_state(TASK_INTERRUPTIBLE);
+ add_timer(&new_timer);
+
+ schedule();
+
+ del_timer_sync(&new_timer);
+ left = rq_time - get_jiffies_64();
+ } while (left > (s64)0 && !test_thread_flag(TIF_SIGPENDING));
+
+ if (abs_wqueue.task_list.next)
+ finish_wait(&nanosleep_abs_wqueue, &abs_wqueue);
+
+ if (left > (s64)0) {
+
+ /*
+ * Always restart abs calls from scratch to pick up any
+ * clock shifting that happened while we are away.
+ */
+ if (abs)
+ return -ERESTARTNOHAND;
+
+ left *= TICK_NSEC;
+ tsave->tv_sec = div_long_long_rem(left,
+ NSEC_PER_SEC,
+ &tsave->tv_nsec);
+ /*
+ * Restart works by saving the time remaing in
+ * arg2 & 3 (it is 64-bits of jiffies). The other
+ * info we need is the clock_id (saved in arg0).
+ * The sys_call interface needs the users
+ * timespec return address which _it_ saves in arg1.
+ * Since we have cast the nanosleep call to a clock_nanosleep
+ * both can be restarted with the same code.
+ */
+ restart_block->fn = clock_nanosleep_restart;
+ restart_block->arg0 = which_clock;
+ /*
+ * Caller sets arg1
+ */
+ restart_block->arg2 = rq_time & 0xffffffffLL;
+ restart_block->arg3 = rq_time >> 32;
+
+ return -ERESTART_RESTARTBLOCK;
+ }
+
+ return 0;
+}
+/*
+ * This will restart clock_nanosleep.
+ */
+long
+clock_nanosleep_restart(struct restart_block *restart_block)
+{
+ struct timespec t;
+ int ret = common_nsleep(restart_block->arg0, 0, &t);
+
+ if ((ret == -ERESTART_RESTARTBLOCK) && restart_block->arg1 &&
+ copy_to_user((struct timespec __user *)(restart_block->arg1), &t,
+ sizeof (t)))
+ return -EFAULT;
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 21:01:22 +0000