linux/kernel/posix-timers.c
john stultz da15cfdae0 time: Introduce CLOCK_REALTIME_COARSE
After talking with some application writers who want very fast, but not
fine-grained timestamps, I decided to try to implement new clock_ids
to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE
which returns the time at the last tick. This is very fast as we don't
have to access any hardware (which can be very painful if you're using
something like the acpi_pm clocksource), and we can even use the vdso
clock_gettime() method to avoid the syscall. The only trade off is you
only get low-res tick grained time resolution.

This isn't a new idea, I know Ingo has a patch in the -rt tree that made
the vsyscall gettimeofday() return coarse grained time when the
vsyscall64 sysctrl was set to 2. However this affects all applications
on a system.

With this method, applications can choose the proper speed/granularity
trade-off for themselves.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: nikolag@ca.ibm.com
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: arjan@infradead.org
Cc: jonathan@jonmasters.org
LKML-Reference: <1250734414.6897.5.camel@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-21 21:43:46 +02:00

1042 lines
29 KiB
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(&current->sighand->siglock);
new_timer->it_signal = current->signal;
list_add(&new_timer->list, &current->signal->posix_timers);
spin_unlock_irq(&current->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(&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).
*/
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));
}