Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1584 insertions, 0 deletions

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
new file mode 100644
index 00000000000..fd316c27226
--- /dev/null
+++ b/kernel/posix-timers.c
@@ -0,0 +1,1584 @@
+/*
+ * 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;
+}