5f82b2b77e
add timespec_valid(ts) [returns false if the timespec is denorm] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1530 lines
43 KiB
C
1530 lines
43 KiB
C
/*
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* linux/kernel/posix_timers.c
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*
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*
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* 2002-10-15 Posix Clocks & timers
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* by George Anzinger george@mvista.com
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*
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* Copyright (C) 2002 2003 by MontaVista Software.
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*
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* 2004-06-01 Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
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* Copyright (C) 2004 Boris Hu
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* MontaVista Software | 1237 East Arques Avenue | Sunnyvale | CA 94085 | USA
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*/
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/* These are all the functions necessary to implement
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* POSIX clocks & timers
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*/
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#include <linux/mm.h>
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#include <linux/smp_lock.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/calc64.h>
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#include <asm/uaccess.h>
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#include <asm/semaphore.h>
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#include <linux/list.h>
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#include <linux/init.h>
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#include <linux/compiler.h>
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#include <linux/idr.h>
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#include <linux/posix-timers.h>
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#include <linux/syscalls.h>
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#include <linux/wait.h>
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#include <linux/workqueue.h>
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#include <linux/module.h>
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#define CLOCK_REALTIME_RES TICK_NSEC /* In nano seconds. */
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static inline u64 mpy_l_X_l_ll(unsigned long mpy1,unsigned long mpy2)
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{
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return (u64)mpy1 * mpy2;
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}
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/*
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* Management arrays for POSIX timers. Timers are kept in slab memory
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* Timer ids are allocated by an external routine that keeps track of the
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* id and the timer. The external interface is:
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*
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* void *idr_find(struct idr *idp, int id); to find timer_id <id>
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* int idr_get_new(struct idr *idp, void *ptr); to get a new id and
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* related it to <ptr>
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* void idr_remove(struct idr *idp, int id); to release <id>
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* void idr_init(struct idr *idp); to initialize <idp>
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* which we supply.
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* The idr_get_new *may* call slab for more memory so it must not be
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* called under a spin lock. Likewise idr_remore may release memory
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* (but it may be ok to do this under a lock...).
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* idr_find is just a memory look up and is quite fast. A -1 return
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* indicates that the requested id does not exist.
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*/
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/*
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* Lets keep our timers in a slab cache :-)
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*/
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static kmem_cache_t *posix_timers_cache;
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static struct idr posix_timers_id;
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static DEFINE_SPINLOCK(idr_lock);
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/*
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* we assume that the new SIGEV_THREAD_ID shares no bits with the other
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* SIGEV values. Here we put out an error if this assumption fails.
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*/
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#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
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~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
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#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
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#endif
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/*
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* The timer ID is turned into a timer address by idr_find().
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* Verifying a valid ID consists of:
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*
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* a) checking that idr_find() returns other than -1.
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* b) checking that the timer id matches the one in the timer itself.
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* c) that the timer owner is in the callers thread group.
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*/
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/*
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* CLOCKs: The POSIX standard calls for a couple of clocks and allows us
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* to implement others. This structure defines the various
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* clocks and allows the possibility of adding others. We
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* provide an interface to add clocks to the table and expect
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* the "arch" code to add at least one clock that is high
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* resolution. Here we define the standard CLOCK_REALTIME as a
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* 1/HZ resolution clock.
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*
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* RESOLUTION: Clock resolution is used to round up timer and interval
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* times, NOT to report clock times, which are reported with as
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* much resolution as the system can muster. In some cases this
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* resolution may depend on the underlying clock hardware and
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* may not be quantifiable until run time, and only then is the
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* necessary code is written. The standard says we should say
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* something about this issue in the documentation...
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*
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* FUNCTIONS: The CLOCKs structure defines possible functions to handle
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* various clock functions. For clocks that use the standard
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* system timer code these entries should be NULL. This will
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* allow dispatch without the overhead of indirect function
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* calls. CLOCKS that depend on other sources (e.g. WWV or GPS)
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* must supply functions here, even if the function just returns
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* ENOSYS. The standard POSIX timer management code assumes the
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* following: 1.) The k_itimer struct (sched.h) is used for the
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* timer. 2.) The list, it_lock, it_clock, it_id and it_process
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* fields are not modified by timer code.
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*
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* At this time all functions EXCEPT clock_nanosleep can be
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* redirected by the CLOCKS structure. Clock_nanosleep is in
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* there, but the code ignores it.
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*
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* Permissions: It is assumed that the clock_settime() function defined
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* for each clock will take care of permission checks. Some
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* clocks may be set able by any user (i.e. local process
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* clocks) others not. Currently the only set able clock we
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* have is CLOCK_REALTIME and its high res counter part, both of
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* which we beg off on and pass to do_sys_settimeofday().
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*/
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static struct k_clock posix_clocks[MAX_CLOCKS];
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/*
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* We only have one real clock that can be set so we need only one abs list,
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* even if we should want to have several clocks with differing resolutions.
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*/
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static struct k_clock_abs abs_list = {.list = LIST_HEAD_INIT(abs_list.list),
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.lock = SPIN_LOCK_UNLOCKED};
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static void posix_timer_fn(unsigned long);
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static u64 do_posix_clock_monotonic_gettime_parts(
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struct timespec *tp, struct timespec *mo);
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int do_posix_clock_monotonic_gettime(struct timespec *tp);
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static int do_posix_clock_monotonic_get(const clockid_t, struct timespec *tp);
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static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags);
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static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
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{
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spin_unlock_irqrestore(&timr->it_lock, flags);
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}
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/*
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* Call the k_clock hook function if non-null, or the default function.
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*/
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#define CLOCK_DISPATCH(clock, call, arglist) \
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((clock) < 0 ? posix_cpu_##call arglist : \
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(posix_clocks[clock].call != NULL \
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? (*posix_clocks[clock].call) arglist : common_##call arglist))
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/*
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* Default clock hook functions when the struct k_clock passed
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* to register_posix_clock leaves a function pointer null.
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*
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* The function common_CALL is the default implementation for
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* the function pointer CALL in struct k_clock.
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*/
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static inline int common_clock_getres(const clockid_t which_clock,
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struct timespec *tp)
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{
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tp->tv_sec = 0;
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tp->tv_nsec = posix_clocks[which_clock].res;
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return 0;
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}
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static inline int common_clock_get(const clockid_t which_clock,
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struct timespec *tp)
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{
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getnstimeofday(tp);
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return 0;
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}
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static inline int common_clock_set(const clockid_t which_clock,
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struct timespec *tp)
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{
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return do_sys_settimeofday(tp, NULL);
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}
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static inline int common_timer_create(struct k_itimer *new_timer)
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{
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INIT_LIST_HEAD(&new_timer->it.real.abs_timer_entry);
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init_timer(&new_timer->it.real.timer);
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new_timer->it.real.timer.data = (unsigned long) new_timer;
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new_timer->it.real.timer.function = posix_timer_fn;
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return 0;
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}
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/*
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* These ones are defined below.
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*/
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static int common_nsleep(const clockid_t, int flags, struct timespec *t);
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static void common_timer_get(struct k_itimer *, struct itimerspec *);
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static int common_timer_set(struct k_itimer *, int,
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struct itimerspec *, struct itimerspec *);
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static int common_timer_del(struct k_itimer *timer);
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/*
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* Return nonzero iff we know a priori this clockid_t value is bogus.
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*/
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static inline int invalid_clockid(const clockid_t which_clock)
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{
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if (which_clock < 0) /* CPU clock, posix_cpu_* will check it */
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return 0;
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if ((unsigned) which_clock >= MAX_CLOCKS)
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return 1;
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if (posix_clocks[which_clock].clock_getres != NULL)
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return 0;
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#ifndef CLOCK_DISPATCH_DIRECT
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if (posix_clocks[which_clock].res != 0)
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return 0;
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#endif
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return 1;
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}
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/*
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* Initialize everything, well, just everything in Posix clocks/timers ;)
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*/
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static __init int init_posix_timers(void)
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{
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struct k_clock clock_realtime = {.res = CLOCK_REALTIME_RES,
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.abs_struct = &abs_list
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};
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struct k_clock clock_monotonic = {.res = CLOCK_REALTIME_RES,
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.abs_struct = NULL,
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.clock_get = do_posix_clock_monotonic_get,
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.clock_set = do_posix_clock_nosettime
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};
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register_posix_clock(CLOCK_REALTIME, &clock_realtime);
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register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
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posix_timers_cache = kmem_cache_create("posix_timers_cache",
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sizeof (struct k_itimer), 0, 0, NULL, NULL);
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idr_init(&posix_timers_id);
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return 0;
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}
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__initcall(init_posix_timers);
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static void tstojiffie(struct timespec *tp, int res, u64 *jiff)
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{
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long sec = tp->tv_sec;
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long nsec = tp->tv_nsec + res - 1;
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if (nsec >= NSEC_PER_SEC) {
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sec++;
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nsec -= NSEC_PER_SEC;
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}
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/*
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* The scaling constants are defined in <linux/time.h>
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* The difference between there and here is that we do the
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* res rounding and compute a 64-bit result (well so does that
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* but it then throws away the high bits).
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*/
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*jiff = (mpy_l_X_l_ll(sec, SEC_CONVERSION) +
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(mpy_l_X_l_ll(nsec, NSEC_CONVERSION) >>
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(NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
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}
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/*
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* This function adjusts the timer as needed as a result of the clock
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* being set. It should only be called for absolute timers, and then
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* under the abs_list lock. It computes the time difference and sets
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* the new jiffies value in the timer. It also updates the timers
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* reference wall_to_monotonic value. It is complicated by the fact
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* that tstojiffies() only handles positive times and it needs to work
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* with both positive and negative times. Also, for negative offsets,
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* we need to defeat the res round up.
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*
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* Return is true if there is a new time, else false.
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*/
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static long add_clockset_delta(struct k_itimer *timr,
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struct timespec *new_wall_to)
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{
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struct timespec delta;
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int sign = 0;
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u64 exp;
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set_normalized_timespec(&delta,
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new_wall_to->tv_sec -
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timr->it.real.wall_to_prev.tv_sec,
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new_wall_to->tv_nsec -
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timr->it.real.wall_to_prev.tv_nsec);
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if (likely(!(delta.tv_sec | delta.tv_nsec)))
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return 0;
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if (delta.tv_sec < 0) {
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set_normalized_timespec(&delta,
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-delta.tv_sec,
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1 - delta.tv_nsec -
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posix_clocks[timr->it_clock].res);
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sign++;
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}
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tstojiffie(&delta, posix_clocks[timr->it_clock].res, &exp);
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timr->it.real.wall_to_prev = *new_wall_to;
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timr->it.real.timer.expires += (sign ? -exp : exp);
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return 1;
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}
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static void remove_from_abslist(struct k_itimer *timr)
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{
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if (!list_empty(&timr->it.real.abs_timer_entry)) {
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spin_lock(&abs_list.lock);
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list_del_init(&timr->it.real.abs_timer_entry);
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spin_unlock(&abs_list.lock);
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}
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}
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static void schedule_next_timer(struct k_itimer *timr)
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{
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struct timespec new_wall_to;
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struct now_struct now;
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unsigned long seq;
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/*
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* Set up the timer for the next interval (if there is one).
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* Note: this code uses the abs_timer_lock to protect
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* it.real.wall_to_prev and must hold it until exp is set, not exactly
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* obvious...
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* This function is used for CLOCK_REALTIME* and
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* CLOCK_MONOTONIC* timers. If we ever want to handle other
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* CLOCKs, the calling code (do_schedule_next_timer) would need
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* to pull the "clock" info from the timer and dispatch the
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* "other" CLOCKs "next timer" code (which, I suppose should
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* also be added to the k_clock structure).
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*/
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if (!timr->it.real.incr)
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return;
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do {
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seq = read_seqbegin(&xtime_lock);
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new_wall_to = wall_to_monotonic;
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posix_get_now(&now);
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} while (read_seqretry(&xtime_lock, seq));
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if (!list_empty(&timr->it.real.abs_timer_entry)) {
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spin_lock(&abs_list.lock);
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add_clockset_delta(timr, &new_wall_to);
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posix_bump_timer(timr, now);
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spin_unlock(&abs_list.lock);
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} else {
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posix_bump_timer(timr, now);
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}
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timr->it_overrun_last = timr->it_overrun;
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timr->it_overrun = -1;
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++timr->it_requeue_pending;
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add_timer(&timr->it.real.timer);
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}
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/*
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* This function is exported for use by the signal deliver code. It is
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* called just prior to the info block being released and passes that
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* block to us. It's function is to update the overrun entry AND to
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* restart the timer. It should only be called if the timer is to be
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* restarted (i.e. we have flagged this in the sys_private entry of the
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* info block).
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*
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* To protect aginst the timer going away while the interrupt is queued,
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* we require that the it_requeue_pending flag be set.
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*/
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void do_schedule_next_timer(struct siginfo *info)
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{
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struct k_itimer *timr;
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unsigned long flags;
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timr = lock_timer(info->si_tid, &flags);
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if (!timr || timr->it_requeue_pending != info->si_sys_private)
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goto exit;
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if (timr->it_clock < 0) /* CPU clock */
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posix_cpu_timer_schedule(timr);
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else
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schedule_next_timer(timr);
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info->si_overrun = timr->it_overrun_last;
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exit:
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if (timr)
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unlock_timer(timr, flags);
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}
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int posix_timer_event(struct k_itimer *timr,int si_private)
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{
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memset(&timr->sigq->info, 0, sizeof(siginfo_t));
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timr->sigq->info.si_sys_private = si_private;
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/*
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* Send signal to the process that owns this timer.
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* This code assumes that all the possible abs_lists share the
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* same lock (there is only one list at this time). If this is
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* not the case, the CLOCK info would need to be used to find
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* the proper abs list lock.
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*/
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timr->sigq->info.si_signo = timr->it_sigev_signo;
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timr->sigq->info.si_errno = 0;
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timr->sigq->info.si_code = SI_TIMER;
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timr->sigq->info.si_tid = timr->it_id;
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timr->sigq->info.si_value = timr->it_sigev_value;
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if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
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struct task_struct *leader;
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int ret = send_sigqueue(timr->it_sigev_signo, timr->sigq,
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timr->it_process);
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if (likely(ret >= 0))
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return ret;
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timr->it_sigev_notify = SIGEV_SIGNAL;
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leader = timr->it_process->group_leader;
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put_task_struct(timr->it_process);
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timr->it_process = leader;
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}
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return send_group_sigqueue(timr->it_sigev_signo, timr->sigq,
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timr->it_process);
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}
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EXPORT_SYMBOL_GPL(posix_timer_event);
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/*
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* This function gets called when a POSIX.1b interval timer expires. It
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* is used as a callback from the kernel internal timer. The
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* run_timer_list code ALWAYS calls with interrupts on.
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* This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
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*/
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static void posix_timer_fn(unsigned long __data)
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{
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struct k_itimer *timr = (struct k_itimer *) __data;
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unsigned long flags;
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unsigned long seq;
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struct timespec delta, new_wall_to;
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u64 exp = 0;
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int do_notify = 1;
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spin_lock_irqsave(&timr->it_lock, flags);
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if (!list_empty(&timr->it.real.abs_timer_entry)) {
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spin_lock(&abs_list.lock);
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do {
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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(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_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(const 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) || !timespec_valid(ts))
|
|
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 and normalize
|
|
*/
|
|
set_normalized_timespec(&oc, oc.tv_sec - now.tv_sec,
|
|
oc.tv_nsec - now.tv_nsec);
|
|
}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.
|
|
*/
|
|
if (try_to_del_timer_sync(&timr->it.real.timer) < 0) {
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* 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;
|
|
#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;
|
|
|
|
if (try_to_del_timer_sync(&timer->it.real.timer) < 0) {
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* 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;
|
|
#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(¤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).
|
|
*/
|
|
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 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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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(const clockid_t clock,
|
|
struct timespec *tp)
|
|
{
|
|
struct timespec wall_to_mono;
|
|
|
|
do_posix_clock_monotonic_gettime_parts(tp, &wall_to_mono);
|
|
|
|
set_normalized_timespec(tp, tp->tv_sec + wall_to_mono.tv_sec,
|
|
tp->tv_nsec + wall_to_mono.tv_nsec);
|
|
|
|
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(const 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(const 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(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));
|
|
}
|
|
|
|
asmlinkage long
|
|
sys_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;
|
|
|
|
}
|
|
|
|
asmlinkage long
|
|
sys_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;
|
|
}
|
|
|
|
/*
|
|
* 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(const 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 (!timespec_valid(&t))
|
|
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(const clockid_t which_clock,
|
|
int flags, struct timespec *tsave)
|
|
{
|
|
struct timespec t, dum;
|
|
DECLARE_WAITQUEUE(abs_wqueue, current);
|
|
u64 rq_time = (u64)0;
|
|
s64 left;
|
|
int abs;
|
|
struct restart_block *restart_block =
|
|
¤t_thread_info()->restart_block;
|
|
|
|
abs_wqueue.flags = 0;
|
|
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;
|
|
|
|
schedule_timeout_interruptible(left);
|
|
|
|
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;
|
|
}
|