Linux-2.6.33.2/kernel/posix-timers.c
/*
* linux/kernel/posix-timers.c
*
*
* 2002-10-15 Posix Clocks & timers
* by George Anzinger george@mvista.com
*
* Copyright (C) 2002 2003 by MontaVista Software.
*
* 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
* Copyright (C) 2004 Boris Hu
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
*/
/* These are all the functions necessary to implement
* POSIX clocks & timers
*/
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/idr.h>
#include <linux/posix-timers.h>
#include <linux/syscalls.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/module.h>
/*
* 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 struct kmem_cache *posix_timers_cache;
static struct idr posix_timers_id;
static DEFINE_SPINLOCK(idr_lock);
/*
* we assume that the new SIGEV_THREAD_ID shares no bits with the other
* SIGEV values. Here we put out an error if this assumption fails.
*/
#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
#endif
/*
* 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_pid
* 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];
/*
* These ones are defined below.
*/
static int common_nsleep(const clockid_t, int flags, struct timespec *t,
struct timespec __user *rmtp);
static void common_timer_get(struct k_itimer *, struct itimerspec *);
static int common_timer_set(struct k_itimer *, int,
struct itimerspec *, struct itimerspec *);
static int common_timer_del(struct k_itimer *timer);
static enum hrtimer_restart posix_timer_fn(struct hrtimer *data);
static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags);
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(const clockid_t which_clock,
struct timespec *tp)
{
tp->tv_sec = 0;
tp->tv_nsec = posix_clocks[which_clock].res;
return 0;
}
/*
* Get real time for posix timers
*/
static int common_clock_get(clockid_t which_clock, struct timespec *tp)
{
ktime_get_real_ts(tp);
return 0;
}
static inline int common_clock_set(const clockid_t which_clock,
struct timespec *tp)
{
return do_sys_settimeofday(tp, NULL);
}
static int common_timer_create(struct k_itimer *new_timer)
{
hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
return 0;
}
static int no_timer_create(struct k_itimer *new_timer)
{
return -EOPNOTSUPP;
}
static int no_nsleep(const clockid_t which_clock, int flags,
struct timespec *tsave, struct timespec __user *rmtp)
{
return -EOPNOTSUPP;
}
/*
* Return nonzero if we know a priori this clockid_t value is bogus.
*/
static inline int invalid_clockid(const 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;
if (posix_clocks[which_clock].res != 0)
return 0;
return 1;
}
/*
* Get monotonic time for posix timers
*/
static int posix_ktime_get_ts(clockid_t which_clock, struct timespec *tp)
{
ktime_get_ts(tp);
return 0;
}
/*
* Get monotonic time for posix timers
*/
static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
{
getrawmonotonic(tp);
return 0;
}
static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
{
*tp = current_kernel_time();
return 0;
}
static int posix_get_monotonic_coarse(clockid_t which_clock,
struct timespec *tp)
{
*tp = get_monotonic_coarse();
return 0;
}
int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
{
*tp = ktime_to_timespec(KTIME_LOW_RES);
return 0;
}
/*
* Initialize everything, well, just everything in Posix clocks/timers ;)
*/
static __init int init_posix_timers(void)
{
struct k_clock clock_realtime = {
.clock_getres = hrtimer_get_res,
};
struct k_clock clock_monotonic = {
.clock_getres = hrtimer_get_res,
.clock_get = posix_ktime_get_ts,
.clock_set = do_posix_clock_nosettime,
};
struct k_clock clock_monotonic_raw = {
.clock_getres = hrtimer_get_res,
.clock_get = posix_get_monotonic_raw,
.clock_set = do_posix_clock_nosettime,
.timer_create = no_timer_create,
.nsleep = no_nsleep,
};
struct k_clock clock_realtime_coarse = {
.clock_getres = posix_get_coarse_res,
.clock_get = posix_get_realtime_coarse,
.clock_set = do_posix_clock_nosettime,
.timer_create = no_timer_create,
.nsleep = no_nsleep,
};
struct k_clock clock_monotonic_coarse = {
.clock_getres = posix_get_coarse_res,
.clock_get = posix_get_monotonic_coarse,
.clock_set = do_posix_clock_nosettime,
.timer_create = no_timer_create,
.nsleep = no_nsleep,
};
register_posix_clock(CLOCK_REALTIME, &clock_realtime);
register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
NULL);
idr_init(&posix_timers_id);
return 0;
}
__initcall(init_posix_timers);
static void schedule_next_timer(struct k_itimer *timr)
{
struct hrtimer *timer = &timr->it.real.timer;
if (timr->it.real.interval.tv64 == 0)
return;
timr->it_overrun += (unsigned int) hrtimer_forward(timer,
timer->base->get_time(),
timr->it.real.interval);
timr->it_overrun_last = timr->it_overrun;
timr->it_overrun = -1;
++timr->it_requeue_pending;
hrtimer_restart(timer);
}
/*
* This function is exported for use by the signal deliver code. It is
* called just prior to the info block being released and passes that
* block to us. It's function is to update the overrun entry AND to
* restart the timer. It should only be called if the timer is to be
* restarted (i.e. we have flagged this in the sys_private entry of the
* info block).
*
* To protect 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) {
if (timr->it_clock < 0)
posix_cpu_timer_schedule(timr);
else
schedule_next_timer(timr);
info->si_overrun += timr->it_overrun_last;
}
if (timr)
unlock_timer(timr, flags);
}
int posix_timer_event(struct k_itimer *timr, int si_private)
{
struct task_struct *task;
int shared, ret = -1;
/*
* FIXME: if ->sigq is queued we can race with
* dequeue_signal()->do_schedule_next_timer().
*
* If dequeue_signal() sees the "right" value of
* si_sys_private it calls do_schedule_next_timer().
* We re-queue ->sigq and drop ->it_lock().
* do_schedule_next_timer() locks the timer
* and re-schedules it while ->sigq is pending.
* Not really bad, but not that we want.
*/
timr->sigq->info.si_sys_private = si_private;
rcu_read_lock();
task = pid_task(timr->it_pid, PIDTYPE_PID);
if (task) {
shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
ret = send_sigqueue(timr->sigq, task, shared);
}
rcu_read_unlock();
/* If we failed to send the signal the timer stops. */
return ret > 0;
}
EXPORT_SYMBOL_GPL(posix_timer_event);
/*
* This function gets called when a POSIX.1b interval timer expires. It
* is used as a callback from the kernel internal timer. The
* run_timer_list code ALWAYS calls with interrupts on.
* This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
*/
static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
{
struct k_itimer *timr;
unsigned long flags;
int si_private = 0;
enum hrtimer_restart ret = HRTIMER_NORESTART;
timr = container_of(timer, struct k_itimer, it.real.timer);
spin_lock_irqsave(&timr->it_lock, flags);
if (timr->it.real.interval.tv64 != 0)
si_private = ++timr->it_requeue_pending;
if (posix_timer_event(timr, si_private)) {
/*
* signal was not sent because of sig_ignor
* we will not get a call back to restart it AND
* it should be restarted.
*/
if (timr->it.real.interval.tv64 != 0) {
ktime_t now = hrtimer_cb_get_time(timer);
/*
* FIXME: What we really want, is to stop this
* timer completely and restart it in case the
* SIG_IGN is removed. This is a non trivial
* change which involves sighand locking
* (sigh !), which we don't want to do late in
* the release cycle.
*
* For now we just let timers with an interval
* less than a jiffie expire every jiffie to
* avoid softirq starvation in case of SIG_IGN
* and a very small interval, which would put
* the timer right back on the softirq pending
* list. By moving now ahead of time we trick
* hrtimer_forward() to expire the timer
* later, while we still maintain the overrun
* accuracy, but have some inconsistency in
* the timer_gettime() case. This is at least
* better than a starved softirq. A more
* complex fix which solves also another related
* inconsistency is already in the pipeline.
*/
#ifdef CONFIG_HIGH_RES_TIMERS
{
ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
if (timr->it.real.interval.tv64 < kj.tv64)
now = ktime_add(now, kj);
}
#endif
timr->it_overrun += (unsigned int)
hrtimer_forward(timer, now,
timr->it.real.interval);
ret = HRTIMER_RESTART;
++timr->it_requeue_pending;
}
}
unlock_timer(timr, flags);
return ret;
}
static struct pid *good_sigevent(sigevent_t * event)
{
struct task_struct *rtn = current->group_leader;
if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
(!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
!same_thread_group(rtn, current) ||
(event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
return NULL;
if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
return NULL;
return task_pid(rtn);
}
void register_posix_clock(const 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_zalloc(posix_timers_cache, GFP_KERNEL);
if (!tmr)
return tmr;
if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
kmem_cache_free(posix_timers_cache, tmr);
return NULL;
}
memset(&tmr->sigq->info, 0, sizeof(siginfo_t));
return tmr;
}
#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);
}
put_pid(tmr->it_pid);
sigqueue_free(tmr->sigq);
kmem_cache_free(posix_timers_cache, tmr);
}
/* Create a POSIX.1b interval timer. */
SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
struct sigevent __user *, timer_event_spec,
timer_t __user *, created_timer_id)
{
struct k_itimer *new_timer;
int error, new_timer_id;
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, new_timer, &new_timer_id);
spin_unlock_irq(&idr_lock);
if (error) {
if (error == -EAGAIN)
goto retry;
/*
* Weird 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;
}
rcu_read_lock();
new_timer->it_pid = get_pid(good_sigevent(&event));
rcu_read_unlock();
if (!new_timer->it_pid) {
error = -EINVAL;
goto out;
}
} else {
event.sigev_notify = SIGEV_SIGNAL;
event.sigev_signo = SIGALRM;
event.sigev_value.sival_int = new_timer->it_id;
new_timer->it_pid = get_pid(task_tgid(current));
}
new_timer->it_sigev_notify = event.sigev_notify;
new_timer->sigq->info.si_signo = event.sigev_signo;
new_timer->sigq->info.si_value = event.sigev_value;
new_timer->sigq->info.si_tid = new_timer->it_id;
new_timer->sigq->info.si_code = SI_TIMER;
spin_lock_irq(¤t->sighand->siglock);
new_timer->it_signal = current->signal;
list_add(&new_timer->list, ¤t->signal->posix_timers);
spin_unlock_irq(¤t->sighand->siglock);
return 0;
/*
* In the case of the timer belonging to another task, after
* the task is unlocked, the timer is owned by the other task
* and may cease to exist at any time. Don't use or modify
* new_timer after the unlock call.
*/
out:
release_posix_timer(new_timer, it_id_set);
return error;
}
/*
* Locking issues: We need to protect the result of the id look up until
* we get the timer locked down so it is not deleted under us. The
* removal is done under the idr spinlock so we use that here to bridge
* the find to the timer lock. To avoid a dead lock, the timer id MUST
* be release with out holding the timer lock.
*/
static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags)
{
struct k_itimer *timr;
/*
* 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 = idr_find(&posix_timers_id, (int)timer_id);
if (timr) {
spin_lock(&timr->it_lock);
if (timr->it_signal == current->signal) {
spin_unlock(&idr_lock);
return timr;
}
spin_unlock(&timr->it_lock);
}
spin_unlock_irqrestore(&idr_lock, *flags);
return NULL;
}
/*
* Get the time remaining on a POSIX.1b interval timer. This function
* is ALWAYS called with spin_lock_irq on the timer, thus it must not
* mess with irq.
*
* We have a couple of messes to clean up here. First there is the case
* of a timer that has a requeue pending. These timers should appear to
* be in the timer list with an expiry as if we were to requeue them
* now.
*
* The second issue is the SIGEV_NONE timer which may be active but is
* not really ever put in the timer list (to save system resources).
* This timer may be expired, and if so, we will do it here. Otherwise
* it is the same as a requeue pending timer WRT to what we should
* report.
*/
static void
common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
{
ktime_t now, remaining, iv;
struct hrtimer *timer = &timr->it.real.timer;
memset(cur_setting, 0, sizeof(struct itimerspec));
iv = timr->it.real.interval;
/* interval timer ? */
if (iv.tv64)
cur_setting->it_interval = ktime_to_timespec(iv);
else if (!hrtimer_active(timer) &&
(timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
return;
now = timer->base->get_time();
/*
* When a requeue is pending or this is a SIGEV_NONE
* timer move the expiry time forward by intervals, so
* expiry is > now.
*/
if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
(timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
remaining = ktime_sub(hrtimer_get_expires(timer), now);
/* Return 0 only, when the timer is expired and not pending */
if (remaining.tv64 <= 0) {
/*
* A single shot SIGEV_NONE timer must return 0, when
* it is expired !
*/
if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE)
cur_setting->it_value.tv_nsec = 1;
} else
cur_setting->it_value = ktime_to_timespec(remaining);
}
/* Get the time remaining on a POSIX.1b interval timer. */
SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
struct itimerspec __user *, setting)
{
struct 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.
*/
SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
{
struct k_itimer *timr;
int overrun;
unsigned long flags;
timr = lock_timer(timer_id, &flags);
if (!timr)
return -EINVAL;
overrun = timr->it_overrun_last;
unlock_timer(timr, flags);
return overrun;
}
/* Set a POSIX.1b interval timer. */
/* timr->it_lock is taken. */
static int
common_timer_set(struct k_itimer *timr, int flags,
struct itimerspec *new_setting, struct itimerspec *old_setting)
{
struct hrtimer *timer = &timr->it.real.timer;
enum hrtimer_mode mode;
if (old_setting)
common_timer_get(timr, old_setting);
/* disable the timer */
timr->it.real.interval.tv64 = 0;
/*
* careful here. If smp we could be in the "fire" routine which will
* be spinning as we hold the lock. But this is ONLY an SMP issue.
*/
if (hrtimer_try_to_cancel(timer) < 0)
return TIMER_RETRY;
timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
~REQUEUE_PENDING;
timr->it_overrun_last = 0;
/* switch off the timer when it_value is zero */
if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
return 0;
mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
timr->it.real.timer.function = posix_timer_fn;
hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
/* Convert interval */
timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
/* SIGEV_NONE timers are not queued ! See common_timer_get */
if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
/* Setup correct expiry time for relative timers */
if (mode == HRTIMER_MODE_REL) {
hrtimer_add_expires(timer, timer->base->get_time());
}
return 0;
}
hrtimer_start_expires(timer, mode);
return 0;
}
/* Set a POSIX.1b interval timer */
SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
const struct itimerspec __user *, new_setting,
struct itimerspec __user *, old_setting)
{
struct k_itimer *timr;
struct itimerspec new_spec, old_spec;
int error = 0;
unsigned long flag;
struct itimerspec *rtn = old_setting ? &old_spec : NULL;
if (!new_setting)
return -EINVAL;
if (copy_from_user(&new_spec, new_setting, sizeof (new_spec)))
return -EFAULT;
if (!timespec_valid(&new_spec.it_interval) ||
!timespec_valid(&new_spec.it_value))
return -EINVAL;
retry:
timr = lock_timer(timer_id, &flag);
if (!timr)
return -EINVAL;
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.interval.tv64 = 0;
if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
return TIMER_RETRY;
return 0;
}
static inline int timer_delete_hook(struct k_itimer *timer)
{
return CLOCK_DISPATCH(timer->it_clock, timer_del, (timer));
}
/* Delete a POSIX.1b interval timer. */
SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
{
struct k_itimer *timer;
unsigned long flags;
retry_delete:
timer = lock_timer(timer_id, &flags);
if (!timer)
return -EINVAL;
if (timer_delete_hook(timer) == TIMER_RETRY) {
unlock_timer(timer, flags);
goto retry_delete;
}
spin_lock(¤t->sighand->siglock);
list_del(&timer->list);
spin_unlock(¤t->sighand->siglock);
/*
* This keeps any tasks waiting on the spin lock from thinking
* they got something (see the lock code above).
*/
timer->it_signal = NULL;
unlock_timer(timer, flags);
release_posix_timer(timer, IT_ID_SET);
return 0;
}
/*
* return timer owned by the process, used by exit_itimers
*/
static void itimer_delete(struct k_itimer *timer)
{
unsigned long flags;
retry_delete:
spin_lock_irqsave(&timer->it_lock, flags);
if (timer_delete_hook(timer) == TIMER_RETRY) {
unlock_timer(timer, flags);
goto retry_delete;
}
list_del(&timer->list);
/*
* This keeps any tasks waiting on the spin lock from thinking
* they got something (see the lock code above).
*/
timer->it_signal = NULL;
unlock_timer(timer, flags);
release_posix_timer(timer, IT_ID_SET);
}
/*
* This is called by do_exit or de_thread, only when there are no more
* references to the shared signal_struct.
*/
void exit_itimers(struct signal_struct *sig)
{
struct k_itimer *tmr;
while (!list_empty(&sig->posix_timers)) {
tmr = list_entry(sig->posix_timers.next, struct k_itimer, list);
itimer_delete(tmr);
}
}
/* Not available / possible... functions */
int do_posix_clock_nosettime(const clockid_t clockid, struct timespec *tp)
{
return -EINVAL;
}
EXPORT_SYMBOL_GPL(do_posix_clock_nosettime);
int do_posix_clock_nonanosleep(const clockid_t clock, int flags,
struct timespec *t, struct timespec __user *r)
{
#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);
SYSCALL_DEFINE2(clock_settime, const 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));
}
SYSCALL_DEFINE2(clock_gettime, const 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;
}
SYSCALL_DEFINE2(clock_getres, const 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;
}
/*
* nanosleep for monotonic and realtime clocks
*/
static int common_nsleep(const clockid_t which_clock, int flags,
struct timespec *tsave, struct timespec __user *rmtp)
{
return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
which_clock);
}
SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
const struct timespec __user *, rqtp,
struct timespec __user *, rmtp)
{
struct timespec t;
if (invalid_clockid(which_clock))
return -EINVAL;
if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
return -EFAULT;
if (!timespec_valid(&t))
return -EINVAL;
return CLOCK_DISPATCH(which_clock, nsleep,
(which_clock, flags, &t, rmtp));
}
/*
* nanosleep_restart for monotonic and realtime clocks
*/
static int common_nsleep_restart(struct restart_block *restart_block)
{
return hrtimer_nanosleep_restart(restart_block);
}
/*
* This will restart clock_nanosleep. This is required only by
* compat_clock_nanosleep_restart for now.
*/
long
clock_nanosleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->arg0;
return CLOCK_DISPATCH(which_clock, nsleep_restart,
(restart_block));
}