mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
58fd3aa288
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
1711 lines
41 KiB
C
1711 lines
41 KiB
C
/*
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* linux/kernel/hrtimer.c
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*
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* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
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* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
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* Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
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*
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* High-resolution kernel timers
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*
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* In contrast to the low-resolution timeout API implemented in
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* kernel/timer.c, hrtimers provide finer resolution and accuracy
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* depending on system configuration and capabilities.
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*
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* These timers are currently used for:
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* - itimers
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* - POSIX timers
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* - nanosleep
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* - precise in-kernel timing
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*
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* Started by: Thomas Gleixner and Ingo Molnar
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*
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* Credits:
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* based on kernel/timer.c
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*
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* Help, testing, suggestions, bugfixes, improvements were
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* provided by:
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*
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* George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
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* et. al.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/percpu.h>
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#include <linux/hrtimer.h>
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#include <linux/notifier.h>
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#include <linux/syscalls.h>
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#include <linux/kallsyms.h>
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#include <linux/interrupt.h>
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#include <linux/tick.h>
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#include <linux/seq_file.h>
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#include <linux/err.h>
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#include <linux/debugobjects.h>
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#include <asm/uaccess.h>
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/**
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* ktime_get - get the monotonic time in ktime_t format
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*
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* returns the time in ktime_t format
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*/
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ktime_t ktime_get(void)
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{
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struct timespec now;
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ktime_get_ts(&now);
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return timespec_to_ktime(now);
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}
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EXPORT_SYMBOL_GPL(ktime_get);
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/**
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* ktime_get_real - get the real (wall-) time in ktime_t format
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*
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* returns the time in ktime_t format
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*/
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ktime_t ktime_get_real(void)
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{
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struct timespec now;
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getnstimeofday(&now);
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return timespec_to_ktime(now);
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}
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EXPORT_SYMBOL_GPL(ktime_get_real);
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/*
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* The timer bases:
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*
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* Note: If we want to add new timer bases, we have to skip the two
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* clock ids captured by the cpu-timers. We do this by holding empty
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* entries rather than doing math adjustment of the clock ids.
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* This ensures that we capture erroneous accesses to these clock ids
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* rather than moving them into the range of valid clock id's.
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*/
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DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
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{
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.clock_base =
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{
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{
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.index = CLOCK_REALTIME,
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.get_time = &ktime_get_real,
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.resolution = KTIME_LOW_RES,
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},
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{
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.index = CLOCK_MONOTONIC,
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.get_time = &ktime_get,
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.resolution = KTIME_LOW_RES,
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},
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}
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};
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/**
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* ktime_get_ts - get the monotonic clock in timespec format
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* @ts: pointer to timespec variable
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*
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* The function calculates the monotonic clock from the realtime
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* clock and the wall_to_monotonic offset and stores the result
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* in normalized timespec format in the variable pointed to by @ts.
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*/
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void ktime_get_ts(struct timespec *ts)
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{
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struct timespec tomono;
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unsigned long seq;
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do {
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seq = read_seqbegin(&xtime_lock);
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getnstimeofday(ts);
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tomono = wall_to_monotonic;
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} while (read_seqretry(&xtime_lock, seq));
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set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
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ts->tv_nsec + tomono.tv_nsec);
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}
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EXPORT_SYMBOL_GPL(ktime_get_ts);
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/*
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* Get the coarse grained time at the softirq based on xtime and
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* wall_to_monotonic.
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*/
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static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
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{
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ktime_t xtim, tomono;
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struct timespec xts, tom;
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unsigned long seq;
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do {
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seq = read_seqbegin(&xtime_lock);
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xts = current_kernel_time();
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tom = wall_to_monotonic;
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} while (read_seqretry(&xtime_lock, seq));
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xtim = timespec_to_ktime(xts);
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tomono = timespec_to_ktime(tom);
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base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
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base->clock_base[CLOCK_MONOTONIC].softirq_time =
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ktime_add(xtim, tomono);
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}
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/*
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* Functions and macros which are different for UP/SMP systems are kept in a
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* single place
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*/
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#ifdef CONFIG_SMP
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/*
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* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
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* means that all timers which are tied to this base via timer->base are
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* locked, and the base itself is locked too.
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*
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* So __run_timers/migrate_timers can safely modify all timers which could
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* be found on the lists/queues.
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*
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* When the timer's base is locked, and the timer removed from list, it is
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* possible to set timer->base = NULL and drop the lock: the timer remains
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* locked.
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*/
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static
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struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
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unsigned long *flags)
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{
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struct hrtimer_clock_base *base;
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for (;;) {
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base = timer->base;
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if (likely(base != NULL)) {
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spin_lock_irqsave(&base->cpu_base->lock, *flags);
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if (likely(base == timer->base))
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return base;
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/* The timer has migrated to another CPU: */
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spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
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}
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cpu_relax();
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}
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}
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/*
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* Switch the timer base to the current CPU when possible.
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*/
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static inline struct hrtimer_clock_base *
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switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base)
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{
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struct hrtimer_clock_base *new_base;
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struct hrtimer_cpu_base *new_cpu_base;
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new_cpu_base = &__get_cpu_var(hrtimer_bases);
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new_base = &new_cpu_base->clock_base[base->index];
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if (base != new_base) {
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/*
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* We are trying to schedule the timer on the local CPU.
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* However we can't change timer's base while it is running,
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* so we keep it on the same CPU. No hassle vs. reprogramming
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* the event source in the high resolution case. The softirq
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* code will take care of this when the timer function has
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* completed. There is no conflict as we hold the lock until
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* the timer is enqueued.
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*/
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if (unlikely(hrtimer_callback_running(timer)))
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return base;
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/* See the comment in lock_timer_base() */
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timer->base = NULL;
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spin_unlock(&base->cpu_base->lock);
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spin_lock(&new_base->cpu_base->lock);
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timer->base = new_base;
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}
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return new_base;
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}
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#else /* CONFIG_SMP */
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static inline struct hrtimer_clock_base *
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lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
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{
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struct hrtimer_clock_base *base = timer->base;
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spin_lock_irqsave(&base->cpu_base->lock, *flags);
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return base;
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}
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# define switch_hrtimer_base(t, b) (b)
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#endif /* !CONFIG_SMP */
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/*
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* Functions for the union type storage format of ktime_t which are
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* too large for inlining:
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*/
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#if BITS_PER_LONG < 64
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# ifndef CONFIG_KTIME_SCALAR
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/**
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* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
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* @kt: addend
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* @nsec: the scalar nsec value to add
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*
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* Returns the sum of kt and nsec in ktime_t format
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*/
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ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
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{
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ktime_t tmp;
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if (likely(nsec < NSEC_PER_SEC)) {
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tmp.tv64 = nsec;
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} else {
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unsigned long rem = do_div(nsec, NSEC_PER_SEC);
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tmp = ktime_set((long)nsec, rem);
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}
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return ktime_add(kt, tmp);
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}
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EXPORT_SYMBOL_GPL(ktime_add_ns);
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/**
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* ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
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* @kt: minuend
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* @nsec: the scalar nsec value to subtract
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*
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* Returns the subtraction of @nsec from @kt in ktime_t format
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*/
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ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
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{
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ktime_t tmp;
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if (likely(nsec < NSEC_PER_SEC)) {
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tmp.tv64 = nsec;
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} else {
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unsigned long rem = do_div(nsec, NSEC_PER_SEC);
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tmp = ktime_set((long)nsec, rem);
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}
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return ktime_sub(kt, tmp);
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}
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EXPORT_SYMBOL_GPL(ktime_sub_ns);
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# endif /* !CONFIG_KTIME_SCALAR */
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/*
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* Divide a ktime value by a nanosecond value
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*/
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u64 ktime_divns(const ktime_t kt, s64 div)
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{
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u64 dclc;
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int sft = 0;
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dclc = ktime_to_ns(kt);
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/* Make sure the divisor is less than 2^32: */
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while (div >> 32) {
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sft++;
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div >>= 1;
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}
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dclc >>= sft;
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do_div(dclc, (unsigned long) div);
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return dclc;
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}
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#endif /* BITS_PER_LONG >= 64 */
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/*
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* Add two ktime values and do a safety check for overflow:
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*/
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ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
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{
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ktime_t res = ktime_add(lhs, rhs);
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/*
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* We use KTIME_SEC_MAX here, the maximum timeout which we can
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* return to user space in a timespec:
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*/
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if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
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res = ktime_set(KTIME_SEC_MAX, 0);
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return res;
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}
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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static struct debug_obj_descr hrtimer_debug_descr;
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/*
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* fixup_init is called when:
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* - an active object is initialized
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*/
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static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
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{
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struct hrtimer *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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hrtimer_cancel(timer);
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debug_object_init(timer, &hrtimer_debug_descr);
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return 1;
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default:
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return 0;
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}
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}
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/*
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* fixup_activate is called when:
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* - an active object is activated
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* - an unknown object is activated (might be a statically initialized object)
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*/
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static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
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{
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switch (state) {
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case ODEBUG_STATE_NOTAVAILABLE:
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WARN_ON_ONCE(1);
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return 0;
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case ODEBUG_STATE_ACTIVE:
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WARN_ON(1);
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default:
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return 0;
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}
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}
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/*
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* fixup_free is called when:
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* - an active object is freed
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*/
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static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
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{
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struct hrtimer *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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hrtimer_cancel(timer);
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debug_object_free(timer, &hrtimer_debug_descr);
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return 1;
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default:
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return 0;
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}
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}
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static struct debug_obj_descr hrtimer_debug_descr = {
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.name = "hrtimer",
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.fixup_init = hrtimer_fixup_init,
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.fixup_activate = hrtimer_fixup_activate,
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.fixup_free = hrtimer_fixup_free,
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};
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static inline void debug_hrtimer_init(struct hrtimer *timer)
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{
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debug_object_init(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_activate(struct hrtimer *timer)
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{
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debug_object_activate(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
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{
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debug_object_deactivate(timer, &hrtimer_debug_descr);
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}
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static inline void debug_hrtimer_free(struct hrtimer *timer)
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{
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debug_object_free(timer, &hrtimer_debug_descr);
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}
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static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
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enum hrtimer_mode mode);
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void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
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enum hrtimer_mode mode)
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{
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debug_object_init_on_stack(timer, &hrtimer_debug_descr);
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__hrtimer_init(timer, clock_id, mode);
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}
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void destroy_hrtimer_on_stack(struct hrtimer *timer)
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{
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debug_object_free(timer, &hrtimer_debug_descr);
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}
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#else
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static inline void debug_hrtimer_init(struct hrtimer *timer) { }
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static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
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static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
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#endif
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/* High resolution timer related functions */
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#ifdef CONFIG_HIGH_RES_TIMERS
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/*
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* High resolution timer enabled ?
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*/
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static int hrtimer_hres_enabled __read_mostly = 1;
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/*
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* Enable / Disable high resolution mode
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*/
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static int __init setup_hrtimer_hres(char *str)
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{
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if (!strcmp(str, "off"))
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hrtimer_hres_enabled = 0;
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else if (!strcmp(str, "on"))
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hrtimer_hres_enabled = 1;
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else
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return 0;
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return 1;
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}
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__setup("highres=", setup_hrtimer_hres);
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/*
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* hrtimer_high_res_enabled - query, if the highres mode is enabled
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*/
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static inline int hrtimer_is_hres_enabled(void)
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{
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return hrtimer_hres_enabled;
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}
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/*
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* Is the high resolution mode active ?
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*/
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static inline int hrtimer_hres_active(void)
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{
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return __get_cpu_var(hrtimer_bases).hres_active;
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}
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/*
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* Reprogram the event source with checking both queues for the
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* next event
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* Called with interrupts disabled and base->lock held
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*/
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static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base)
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{
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int i;
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struct hrtimer_clock_base *base = cpu_base->clock_base;
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ktime_t expires;
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cpu_base->expires_next.tv64 = KTIME_MAX;
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for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
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struct hrtimer *timer;
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if (!base->first)
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continue;
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timer = rb_entry(base->first, struct hrtimer, node);
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expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
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if (expires.tv64 < cpu_base->expires_next.tv64)
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cpu_base->expires_next = expires;
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}
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if (cpu_base->expires_next.tv64 != KTIME_MAX)
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tick_program_event(cpu_base->expires_next, 1);
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}
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/*
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* Shared reprogramming for clock_realtime and clock_monotonic
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*
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* When a timer is enqueued and expires earlier than the already enqueued
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* timers, we have to check, whether it expires earlier than the timer for
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* which the clock event device was armed.
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*
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* Called with interrupts disabled and base->cpu_base.lock held
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*/
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static int hrtimer_reprogram(struct hrtimer *timer,
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struct hrtimer_clock_base *base)
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{
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ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
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ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
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int res;
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WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
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|
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/*
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* When the callback is running, we do not reprogram the clock event
|
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* device. The timer callback is either running on a different CPU or
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* the callback is executed in the hrtimer_interrupt context. The
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|
* reprogramming is handled either by the softirq, which called the
|
|
* callback or at the end of the hrtimer_interrupt.
|
|
*/
|
|
if (hrtimer_callback_running(timer))
|
|
return 0;
|
|
|
|
/*
|
|
* CLOCK_REALTIME timer might be requested with an absolute
|
|
* expiry time which is less than base->offset. Nothing wrong
|
|
* about that, just avoid to call into the tick code, which
|
|
* has now objections against negative expiry values.
|
|
*/
|
|
if (expires.tv64 < 0)
|
|
return -ETIME;
|
|
|
|
if (expires.tv64 >= expires_next->tv64)
|
|
return 0;
|
|
|
|
/*
|
|
* Clockevents returns -ETIME, when the event was in the past.
|
|
*/
|
|
res = tick_program_event(expires, 0);
|
|
if (!IS_ERR_VALUE(res))
|
|
*expires_next = expires;
|
|
return res;
|
|
}
|
|
|
|
|
|
/*
|
|
* Retrigger next event is called after clock was set
|
|
*
|
|
* Called with interrupts disabled via on_each_cpu()
|
|
*/
|
|
static void retrigger_next_event(void *arg)
|
|
{
|
|
struct hrtimer_cpu_base *base;
|
|
struct timespec realtime_offset;
|
|
unsigned long seq;
|
|
|
|
if (!hrtimer_hres_active())
|
|
return;
|
|
|
|
do {
|
|
seq = read_seqbegin(&xtime_lock);
|
|
set_normalized_timespec(&realtime_offset,
|
|
-wall_to_monotonic.tv_sec,
|
|
-wall_to_monotonic.tv_nsec);
|
|
} while (read_seqretry(&xtime_lock, seq));
|
|
|
|
base = &__get_cpu_var(hrtimer_bases);
|
|
|
|
/* Adjust CLOCK_REALTIME offset */
|
|
spin_lock(&base->lock);
|
|
base->clock_base[CLOCK_REALTIME].offset =
|
|
timespec_to_ktime(realtime_offset);
|
|
|
|
hrtimer_force_reprogram(base);
|
|
spin_unlock(&base->lock);
|
|
}
|
|
|
|
/*
|
|
* Clock realtime was set
|
|
*
|
|
* Change the offset of the realtime clock vs. the monotonic
|
|
* clock.
|
|
*
|
|
* We might have to reprogram the high resolution timer interrupt. On
|
|
* SMP we call the architecture specific code to retrigger _all_ high
|
|
* resolution timer interrupts. On UP we just disable interrupts and
|
|
* call the high resolution interrupt code.
|
|
*/
|
|
void clock_was_set(void)
|
|
{
|
|
/* Retrigger the CPU local events everywhere */
|
|
on_each_cpu(retrigger_next_event, NULL, 1);
|
|
}
|
|
|
|
/*
|
|
* During resume we might have to reprogram the high resolution timer
|
|
* interrupt (on the local CPU):
|
|
*/
|
|
void hres_timers_resume(void)
|
|
{
|
|
/* Retrigger the CPU local events: */
|
|
retrigger_next_event(NULL);
|
|
}
|
|
|
|
/*
|
|
* Initialize the high resolution related parts of cpu_base
|
|
*/
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
|
|
{
|
|
base->expires_next.tv64 = KTIME_MAX;
|
|
base->hres_active = 0;
|
|
}
|
|
|
|
/*
|
|
* Initialize the high resolution related parts of a hrtimer
|
|
*/
|
|
static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
|
|
{
|
|
}
|
|
|
|
|
|
/*
|
|
* When High resolution timers are active, try to reprogram. Note, that in case
|
|
* the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
|
|
* check happens. The timer gets enqueued into the rbtree. The reprogramming
|
|
* and expiry check is done in the hrtimer_interrupt or in the softirq.
|
|
*/
|
|
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
|
|
spin_unlock(&base->cpu_base->lock);
|
|
raise_softirq_irqoff(HRTIMER_SOFTIRQ);
|
|
spin_lock(&base->cpu_base->lock);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Switch to high resolution mode
|
|
*/
|
|
static int hrtimer_switch_to_hres(void)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
|
|
unsigned long flags;
|
|
|
|
if (base->hres_active)
|
|
return 1;
|
|
|
|
local_irq_save(flags);
|
|
|
|
if (tick_init_highres()) {
|
|
local_irq_restore(flags);
|
|
printk(KERN_WARNING "Could not switch to high resolution "
|
|
"mode on CPU %d\n", cpu);
|
|
return 0;
|
|
}
|
|
base->hres_active = 1;
|
|
base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES;
|
|
base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES;
|
|
|
|
tick_setup_sched_timer();
|
|
|
|
/* "Retrigger" the interrupt to get things going */
|
|
retrigger_next_event(NULL);
|
|
local_irq_restore(flags);
|
|
printk(KERN_DEBUG "Switched to high resolution mode on CPU %d\n",
|
|
smp_processor_id());
|
|
return 1;
|
|
}
|
|
|
|
#else
|
|
|
|
static inline int hrtimer_hres_active(void) { return 0; }
|
|
static inline int hrtimer_is_hres_enabled(void) { return 0; }
|
|
static inline int hrtimer_switch_to_hres(void) { return 0; }
|
|
static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { }
|
|
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
|
|
static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
|
|
|
|
#endif /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
#ifdef CONFIG_TIMER_STATS
|
|
void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr)
|
|
{
|
|
if (timer->start_site)
|
|
return;
|
|
|
|
timer->start_site = addr;
|
|
memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
|
|
timer->start_pid = current->pid;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Counterpart to lock_hrtimer_base above:
|
|
*/
|
|
static inline
|
|
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
|
|
{
|
|
spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
|
|
}
|
|
|
|
/**
|
|
* hrtimer_forward - forward the timer expiry
|
|
* @timer: hrtimer to forward
|
|
* @now: forward past this time
|
|
* @interval: the interval to forward
|
|
*
|
|
* Forward the timer expiry so it will expire in the future.
|
|
* Returns the number of overruns.
|
|
*/
|
|
u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
|
|
{
|
|
u64 orun = 1;
|
|
ktime_t delta;
|
|
|
|
delta = ktime_sub(now, hrtimer_get_expires(timer));
|
|
|
|
if (delta.tv64 < 0)
|
|
return 0;
|
|
|
|
if (interval.tv64 < timer->base->resolution.tv64)
|
|
interval.tv64 = timer->base->resolution.tv64;
|
|
|
|
if (unlikely(delta.tv64 >= interval.tv64)) {
|
|
s64 incr = ktime_to_ns(interval);
|
|
|
|
orun = ktime_divns(delta, incr);
|
|
hrtimer_add_expires_ns(timer, incr * orun);
|
|
if (hrtimer_get_expires_tv64(timer) > now.tv64)
|
|
return orun;
|
|
/*
|
|
* This (and the ktime_add() below) is the
|
|
* correction for exact:
|
|
*/
|
|
orun++;
|
|
}
|
|
hrtimer_add_expires(timer, interval);
|
|
|
|
return orun;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_forward);
|
|
|
|
/*
|
|
* enqueue_hrtimer - internal function to (re)start a timer
|
|
*
|
|
* The timer is inserted in expiry order. Insertion into the
|
|
* red black tree is O(log(n)). Must hold the base lock.
|
|
*
|
|
* Returns 1 when the new timer is the leftmost timer in the tree.
|
|
*/
|
|
static int enqueue_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base)
|
|
{
|
|
struct rb_node **link = &base->active.rb_node;
|
|
struct rb_node *parent = NULL;
|
|
struct hrtimer *entry;
|
|
int leftmost = 1;
|
|
|
|
debug_hrtimer_activate(timer);
|
|
|
|
/*
|
|
* Find the right place in the rbtree:
|
|
*/
|
|
while (*link) {
|
|
parent = *link;
|
|
entry = rb_entry(parent, struct hrtimer, node);
|
|
/*
|
|
* We dont care about collisions. Nodes with
|
|
* the same expiry time stay together.
|
|
*/
|
|
if (hrtimer_get_expires_tv64(timer) <
|
|
hrtimer_get_expires_tv64(entry)) {
|
|
link = &(*link)->rb_left;
|
|
} else {
|
|
link = &(*link)->rb_right;
|
|
leftmost = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Insert the timer to the rbtree and check whether it
|
|
* replaces the first pending timer
|
|
*/
|
|
if (leftmost)
|
|
base->first = &timer->node;
|
|
|
|
rb_link_node(&timer->node, parent, link);
|
|
rb_insert_color(&timer->node, &base->active);
|
|
/*
|
|
* HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
|
|
* state of a possibly running callback.
|
|
*/
|
|
timer->state |= HRTIMER_STATE_ENQUEUED;
|
|
|
|
return leftmost;
|
|
}
|
|
|
|
/*
|
|
* __remove_hrtimer - internal function to remove a timer
|
|
*
|
|
* Caller must hold the base lock.
|
|
*
|
|
* High resolution timer mode reprograms the clock event device when the
|
|
* timer is the one which expires next. The caller can disable this by setting
|
|
* reprogram to zero. This is useful, when the context does a reprogramming
|
|
* anyway (e.g. timer interrupt)
|
|
*/
|
|
static void __remove_hrtimer(struct hrtimer *timer,
|
|
struct hrtimer_clock_base *base,
|
|
unsigned long newstate, int reprogram)
|
|
{
|
|
if (timer->state & HRTIMER_STATE_ENQUEUED) {
|
|
/*
|
|
* Remove the timer from the rbtree and replace the
|
|
* first entry pointer if necessary.
|
|
*/
|
|
if (base->first == &timer->node) {
|
|
base->first = rb_next(&timer->node);
|
|
/* Reprogram the clock event device. if enabled */
|
|
if (reprogram && hrtimer_hres_active())
|
|
hrtimer_force_reprogram(base->cpu_base);
|
|
}
|
|
rb_erase(&timer->node, &base->active);
|
|
}
|
|
timer->state = newstate;
|
|
}
|
|
|
|
/*
|
|
* remove hrtimer, called with base lock held
|
|
*/
|
|
static inline int
|
|
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
|
|
{
|
|
if (hrtimer_is_queued(timer)) {
|
|
int reprogram;
|
|
|
|
/*
|
|
* Remove the timer and force reprogramming when high
|
|
* resolution mode is active and the timer is on the current
|
|
* CPU. If we remove a timer on another CPU, reprogramming is
|
|
* skipped. The interrupt event on this CPU is fired and
|
|
* reprogramming happens in the interrupt handler. This is a
|
|
* rare case and less expensive than a smp call.
|
|
*/
|
|
debug_hrtimer_deactivate(timer);
|
|
timer_stats_hrtimer_clear_start_info(timer);
|
|
reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
|
|
__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
|
|
reprogram);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
|
|
* @timer: the timer to be added
|
|
* @tim: expiry time
|
|
* @delta_ns: "slack" range for the timer
|
|
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
|
|
*
|
|
* Returns:
|
|
* 0 on success
|
|
* 1 when the timer was active
|
|
*/
|
|
int
|
|
hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_ns,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_clock_base *base, *new_base;
|
|
unsigned long flags;
|
|
int ret, leftmost;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
/* Remove an active timer from the queue: */
|
|
ret = remove_hrtimer(timer, base);
|
|
|
|
/* Switch the timer base, if necessary: */
|
|
new_base = switch_hrtimer_base(timer, base);
|
|
|
|
if (mode == HRTIMER_MODE_REL) {
|
|
tim = ktime_add_safe(tim, new_base->get_time());
|
|
/*
|
|
* CONFIG_TIME_LOW_RES is a temporary way for architectures
|
|
* to signal that they simply return xtime in
|
|
* do_gettimeoffset(). In this case we want to round up by
|
|
* resolution when starting a relative timer, to avoid short
|
|
* timeouts. This will go away with the GTOD framework.
|
|
*/
|
|
#ifdef CONFIG_TIME_LOW_RES
|
|
tim = ktime_add_safe(tim, base->resolution);
|
|
#endif
|
|
}
|
|
|
|
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
|
|
|
|
timer_stats_hrtimer_set_start_info(timer);
|
|
|
|
leftmost = enqueue_hrtimer(timer, new_base);
|
|
|
|
/*
|
|
* Only allow reprogramming if the new base is on this CPU.
|
|
* (it might still be on another CPU if the timer was pending)
|
|
*
|
|
* XXX send_remote_softirq() ?
|
|
*/
|
|
if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
|
|
hrtimer_enqueue_reprogram(timer, new_base);
|
|
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
|
|
|
|
/**
|
|
* hrtimer_start - (re)start an hrtimer on the current CPU
|
|
* @timer: the timer to be added
|
|
* @tim: expiry time
|
|
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
|
|
*
|
|
* Returns:
|
|
* 0 on success
|
|
* 1 when the timer was active
|
|
*/
|
|
int
|
|
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
|
|
{
|
|
return hrtimer_start_range_ns(timer, tim, 0, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_start);
|
|
|
|
|
|
/**
|
|
* hrtimer_try_to_cancel - try to deactivate a timer
|
|
* @timer: hrtimer to stop
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
* -1 when the timer is currently excuting the callback function and
|
|
* cannot be stopped
|
|
*/
|
|
int hrtimer_try_to_cancel(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base;
|
|
unsigned long flags;
|
|
int ret = -1;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
|
|
if (!hrtimer_callback_running(timer))
|
|
ret = remove_hrtimer(timer, base);
|
|
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return ret;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
|
|
|
|
/**
|
|
* hrtimer_cancel - cancel a timer and wait for the handler to finish.
|
|
* @timer: the timer to be cancelled
|
|
*
|
|
* Returns:
|
|
* 0 when the timer was not active
|
|
* 1 when the timer was active
|
|
*/
|
|
int hrtimer_cancel(struct hrtimer *timer)
|
|
{
|
|
for (;;) {
|
|
int ret = hrtimer_try_to_cancel(timer);
|
|
|
|
if (ret >= 0)
|
|
return ret;
|
|
cpu_relax();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_cancel);
|
|
|
|
/**
|
|
* hrtimer_get_remaining - get remaining time for the timer
|
|
* @timer: the timer to read
|
|
*/
|
|
ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base;
|
|
unsigned long flags;
|
|
ktime_t rem;
|
|
|
|
base = lock_hrtimer_base(timer, &flags);
|
|
rem = hrtimer_expires_remaining(timer);
|
|
unlock_hrtimer_base(timer, &flags);
|
|
|
|
return rem;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
|
|
|
|
#ifdef CONFIG_NO_HZ
|
|
/**
|
|
* hrtimer_get_next_event - get the time until next expiry event
|
|
*
|
|
* Returns the delta to the next expiry event or KTIME_MAX if no timer
|
|
* is pending.
|
|
*/
|
|
ktime_t hrtimer_get_next_event(void)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
struct hrtimer_clock_base *base = cpu_base->clock_base;
|
|
ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
spin_lock_irqsave(&cpu_base->lock, flags);
|
|
|
|
if (!hrtimer_hres_active()) {
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
|
|
struct hrtimer *timer;
|
|
|
|
if (!base->first)
|
|
continue;
|
|
|
|
timer = rb_entry(base->first, struct hrtimer, node);
|
|
delta.tv64 = hrtimer_get_expires_tv64(timer);
|
|
delta = ktime_sub(delta, base->get_time());
|
|
if (delta.tv64 < mindelta.tv64)
|
|
mindelta.tv64 = delta.tv64;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&cpu_base->lock, flags);
|
|
|
|
if (mindelta.tv64 < 0)
|
|
mindelta.tv64 = 0;
|
|
return mindelta;
|
|
}
|
|
#endif
|
|
|
|
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
|
|
memset(timer, 0, sizeof(struct hrtimer));
|
|
|
|
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
|
|
|
|
if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
|
|
clock_id = CLOCK_MONOTONIC;
|
|
|
|
timer->base = &cpu_base->clock_base[clock_id];
|
|
INIT_LIST_HEAD(&timer->cb_entry);
|
|
hrtimer_init_timer_hres(timer);
|
|
|
|
#ifdef CONFIG_TIMER_STATS
|
|
timer->start_site = NULL;
|
|
timer->start_pid = -1;
|
|
memset(timer->start_comm, 0, TASK_COMM_LEN);
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* hrtimer_init - initialize a timer to the given clock
|
|
* @timer: the timer to be initialized
|
|
* @clock_id: the clock to be used
|
|
* @mode: timer mode abs/rel
|
|
*/
|
|
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
|
|
enum hrtimer_mode mode)
|
|
{
|
|
debug_hrtimer_init(timer);
|
|
__hrtimer_init(timer, clock_id, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_init);
|
|
|
|
/**
|
|
* hrtimer_get_res - get the timer resolution for a clock
|
|
* @which_clock: which clock to query
|
|
* @tp: pointer to timespec variable to store the resolution
|
|
*
|
|
* Store the resolution of the clock selected by @which_clock in the
|
|
* variable pointed to by @tp.
|
|
*/
|
|
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base;
|
|
|
|
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
|
|
*tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hrtimer_get_res);
|
|
|
|
static void __run_hrtimer(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base = timer->base;
|
|
struct hrtimer_cpu_base *cpu_base = base->cpu_base;
|
|
enum hrtimer_restart (*fn)(struct hrtimer *);
|
|
int restart;
|
|
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
debug_hrtimer_deactivate(timer);
|
|
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
|
|
timer_stats_account_hrtimer(timer);
|
|
fn = timer->function;
|
|
|
|
/*
|
|
* Because we run timers from hardirq context, there is no chance
|
|
* they get migrated to another cpu, therefore its safe to unlock
|
|
* the timer base.
|
|
*/
|
|
spin_unlock(&cpu_base->lock);
|
|
restart = fn(timer);
|
|
spin_lock(&cpu_base->lock);
|
|
|
|
/*
|
|
* Note: We clear the CALLBACK bit after enqueue_hrtimer and
|
|
* we do not reprogramm the event hardware. Happens either in
|
|
* hrtimer_start_range_ns() or in hrtimer_interrupt()
|
|
*/
|
|
if (restart != HRTIMER_NORESTART) {
|
|
BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
|
|
enqueue_hrtimer(timer, base);
|
|
}
|
|
timer->state &= ~HRTIMER_STATE_CALLBACK;
|
|
}
|
|
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
|
|
|
|
/*
|
|
* High resolution timer interrupt
|
|
* Called with interrupts disabled
|
|
*/
|
|
void hrtimer_interrupt(struct clock_event_device *dev)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
struct hrtimer_clock_base *base;
|
|
ktime_t expires_next, now;
|
|
int i;
|
|
|
|
BUG_ON(!cpu_base->hres_active);
|
|
cpu_base->nr_events++;
|
|
dev->next_event.tv64 = KTIME_MAX;
|
|
|
|
retry:
|
|
now = ktime_get();
|
|
|
|
expires_next.tv64 = KTIME_MAX;
|
|
|
|
base = cpu_base->clock_base;
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
ktime_t basenow;
|
|
struct rb_node *node;
|
|
|
|
spin_lock(&cpu_base->lock);
|
|
|
|
basenow = ktime_add(now, base->offset);
|
|
|
|
while ((node = base->first)) {
|
|
struct hrtimer *timer;
|
|
|
|
timer = rb_entry(node, struct hrtimer, node);
|
|
|
|
/*
|
|
* The immediate goal for using the softexpires is
|
|
* minimizing wakeups, not running timers at the
|
|
* earliest interrupt after their soft expiration.
|
|
* This allows us to avoid using a Priority Search
|
|
* Tree, which can answer a stabbing querry for
|
|
* overlapping intervals and instead use the simple
|
|
* BST we already have.
|
|
* We don't add extra wakeups by delaying timers that
|
|
* are right-of a not yet expired timer, because that
|
|
* timer will have to trigger a wakeup anyway.
|
|
*/
|
|
|
|
if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
|
|
ktime_t expires;
|
|
|
|
expires = ktime_sub(hrtimer_get_expires(timer),
|
|
base->offset);
|
|
if (expires.tv64 < expires_next.tv64)
|
|
expires_next = expires;
|
|
break;
|
|
}
|
|
|
|
__run_hrtimer(timer);
|
|
}
|
|
spin_unlock(&cpu_base->lock);
|
|
base++;
|
|
}
|
|
|
|
cpu_base->expires_next = expires_next;
|
|
|
|
/* Reprogramming necessary ? */
|
|
if (expires_next.tv64 != KTIME_MAX) {
|
|
if (tick_program_event(expires_next, 0))
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* local version of hrtimer_peek_ahead_timers() called with interrupts
|
|
* disabled.
|
|
*/
|
|
static void __hrtimer_peek_ahead_timers(void)
|
|
{
|
|
struct tick_device *td;
|
|
|
|
if (!hrtimer_hres_active())
|
|
return;
|
|
|
|
td = &__get_cpu_var(tick_cpu_device);
|
|
if (td && td->evtdev)
|
|
hrtimer_interrupt(td->evtdev);
|
|
}
|
|
|
|
/**
|
|
* hrtimer_peek_ahead_timers -- run soft-expired timers now
|
|
*
|
|
* hrtimer_peek_ahead_timers will peek at the timer queue of
|
|
* the current cpu and check if there are any timers for which
|
|
* the soft expires time has passed. If any such timers exist,
|
|
* they are run immediately and then removed from the timer queue.
|
|
*
|
|
*/
|
|
void hrtimer_peek_ahead_timers(void)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
__hrtimer_peek_ahead_timers();
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static void run_hrtimer_softirq(struct softirq_action *h)
|
|
{
|
|
hrtimer_peek_ahead_timers();
|
|
}
|
|
|
|
#else /* CONFIG_HIGH_RES_TIMERS */
|
|
|
|
static inline void __hrtimer_peek_ahead_timers(void) { }
|
|
|
|
#endif /* !CONFIG_HIGH_RES_TIMERS */
|
|
|
|
/*
|
|
* Called from timer softirq every jiffy, expire hrtimers:
|
|
*
|
|
* For HRT its the fall back code to run the softirq in the timer
|
|
* softirq context in case the hrtimer initialization failed or has
|
|
* not been done yet.
|
|
*/
|
|
void hrtimer_run_pending(void)
|
|
{
|
|
if (hrtimer_hres_active())
|
|
return;
|
|
|
|
/*
|
|
* This _is_ ugly: We have to check in the softirq context,
|
|
* whether we can switch to highres and / or nohz mode. The
|
|
* clocksource switch happens in the timer interrupt with
|
|
* xtime_lock held. Notification from there only sets the
|
|
* check bit in the tick_oneshot code, otherwise we might
|
|
* deadlock vs. xtime_lock.
|
|
*/
|
|
if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
|
|
hrtimer_switch_to_hres();
|
|
}
|
|
|
|
/*
|
|
* Called from hardirq context every jiffy
|
|
*/
|
|
void hrtimer_run_queues(void)
|
|
{
|
|
struct rb_node *node;
|
|
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
|
|
struct hrtimer_clock_base *base;
|
|
int index, gettime = 1;
|
|
|
|
if (hrtimer_hres_active())
|
|
return;
|
|
|
|
for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
|
|
base = &cpu_base->clock_base[index];
|
|
|
|
if (!base->first)
|
|
continue;
|
|
|
|
if (gettime) {
|
|
hrtimer_get_softirq_time(cpu_base);
|
|
gettime = 0;
|
|
}
|
|
|
|
spin_lock(&cpu_base->lock);
|
|
|
|
while ((node = base->first)) {
|
|
struct hrtimer *timer;
|
|
|
|
timer = rb_entry(node, struct hrtimer, node);
|
|
if (base->softirq_time.tv64 <=
|
|
hrtimer_get_expires_tv64(timer))
|
|
break;
|
|
|
|
__run_hrtimer(timer);
|
|
}
|
|
spin_unlock(&cpu_base->lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Sleep related functions:
|
|
*/
|
|
static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_sleeper *t =
|
|
container_of(timer, struct hrtimer_sleeper, timer);
|
|
struct task_struct *task = t->task;
|
|
|
|
t->task = NULL;
|
|
if (task)
|
|
wake_up_process(task);
|
|
|
|
return HRTIMER_NORESTART;
|
|
}
|
|
|
|
void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
|
|
{
|
|
sl->timer.function = hrtimer_wakeup;
|
|
sl->task = task;
|
|
}
|
|
|
|
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
|
|
{
|
|
hrtimer_init_sleeper(t, current);
|
|
|
|
do {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
hrtimer_start_expires(&t->timer, mode);
|
|
if (!hrtimer_active(&t->timer))
|
|
t->task = NULL;
|
|
|
|
if (likely(t->task))
|
|
schedule();
|
|
|
|
hrtimer_cancel(&t->timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
|
|
} while (t->task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return t->task == NULL;
|
|
}
|
|
|
|
static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
|
|
{
|
|
struct timespec rmt;
|
|
ktime_t rem;
|
|
|
|
rem = hrtimer_expires_remaining(timer);
|
|
if (rem.tv64 <= 0)
|
|
return 0;
|
|
rmt = ktime_to_timespec(rem);
|
|
|
|
if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
|
|
return -EFAULT;
|
|
|
|
return 1;
|
|
}
|
|
|
|
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
struct timespec __user *rmtp;
|
|
int ret = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
|
|
HRTIMER_MODE_ABS);
|
|
hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
|
|
|
|
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
|
|
goto out;
|
|
|
|
rmtp = restart->nanosleep.rmtp;
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
/* The other values in restart are already filled in */
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
|
|
const enum hrtimer_mode mode, const clockid_t clockid)
|
|
{
|
|
struct restart_block *restart;
|
|
struct hrtimer_sleeper t;
|
|
int ret = 0;
|
|
unsigned long slack;
|
|
|
|
slack = current->timer_slack_ns;
|
|
if (rt_task(current))
|
|
slack = 0;
|
|
|
|
hrtimer_init_on_stack(&t.timer, clockid, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
|
|
if (do_nanosleep(&t, mode))
|
|
goto out;
|
|
|
|
/* Absolute timers do not update the rmtp value and restart: */
|
|
if (mode == HRTIMER_MODE_ABS) {
|
|
ret = -ERESTARTNOHAND;
|
|
goto out;
|
|
}
|
|
|
|
if (rmtp) {
|
|
ret = update_rmtp(&t.timer, rmtp);
|
|
if (ret <= 0)
|
|
goto out;
|
|
}
|
|
|
|
restart = ¤t_thread_info()->restart_block;
|
|
restart->fn = hrtimer_nanosleep_restart;
|
|
restart->nanosleep.index = t.timer.base->index;
|
|
restart->nanosleep.rmtp = rmtp;
|
|
restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
out:
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
|
|
struct timespec __user *, rmtp)
|
|
{
|
|
struct timespec tu;
|
|
|
|
if (copy_from_user(&tu, rqtp, sizeof(tu)))
|
|
return -EFAULT;
|
|
|
|
if (!timespec_valid(&tu))
|
|
return -EINVAL;
|
|
|
|
return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
|
|
}
|
|
|
|
/*
|
|
* Functions related to boot-time initialization:
|
|
*/
|
|
static void __cpuinit init_hrtimers_cpu(int cpu)
|
|
{
|
|
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
|
|
int i;
|
|
|
|
spin_lock_init(&cpu_base->lock);
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
|
|
cpu_base->clock_base[i].cpu_base = cpu_base;
|
|
|
|
hrtimer_init_hres(cpu_base);
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
|
|
struct hrtimer_clock_base *new_base)
|
|
{
|
|
struct hrtimer *timer;
|
|
struct rb_node *node;
|
|
|
|
while ((node = rb_first(&old_base->active))) {
|
|
timer = rb_entry(node, struct hrtimer, node);
|
|
BUG_ON(hrtimer_callback_running(timer));
|
|
debug_hrtimer_deactivate(timer);
|
|
|
|
/*
|
|
* Mark it as STATE_MIGRATE not INACTIVE otherwise the
|
|
* timer could be seen as !active and just vanish away
|
|
* under us on another CPU
|
|
*/
|
|
__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
|
|
timer->base = new_base;
|
|
/*
|
|
* Enqueue the timers on the new cpu. This does not
|
|
* reprogram the event device in case the timer
|
|
* expires before the earliest on this CPU, but we run
|
|
* hrtimer_interrupt after we migrated everything to
|
|
* sort out already expired timers and reprogram the
|
|
* event device.
|
|
*/
|
|
enqueue_hrtimer(timer, new_base);
|
|
|
|
/* Clear the migration state bit */
|
|
timer->state &= ~HRTIMER_STATE_MIGRATE;
|
|
}
|
|
}
|
|
|
|
static void migrate_hrtimers(int scpu)
|
|
{
|
|
struct hrtimer_cpu_base *old_base, *new_base;
|
|
int i;
|
|
|
|
BUG_ON(cpu_online(scpu));
|
|
tick_cancel_sched_timer(scpu);
|
|
|
|
local_irq_disable();
|
|
old_base = &per_cpu(hrtimer_bases, scpu);
|
|
new_base = &__get_cpu_var(hrtimer_bases);
|
|
/*
|
|
* The caller is globally serialized and nobody else
|
|
* takes two locks at once, deadlock is not possible.
|
|
*/
|
|
spin_lock(&new_base->lock);
|
|
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
|
|
|
|
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
|
|
migrate_hrtimer_list(&old_base->clock_base[i],
|
|
&new_base->clock_base[i]);
|
|
}
|
|
|
|
spin_unlock(&old_base->lock);
|
|
spin_unlock(&new_base->lock);
|
|
|
|
/* Check, if we got expired work to do */
|
|
__hrtimer_peek_ahead_timers();
|
|
local_irq_enable();
|
|
}
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
int scpu = (long)hcpu;
|
|
|
|
switch (action) {
|
|
|
|
case CPU_UP_PREPARE:
|
|
case CPU_UP_PREPARE_FROZEN:
|
|
init_hrtimers_cpu(scpu);
|
|
break;
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_DEAD:
|
|
case CPU_DEAD_FROZEN:
|
|
{
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
|
|
migrate_hrtimers(scpu);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block __cpuinitdata hrtimers_nb = {
|
|
.notifier_call = hrtimer_cpu_notify,
|
|
};
|
|
|
|
void __init hrtimers_init(void)
|
|
{
|
|
hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
|
|
(void *)(long)smp_processor_id());
|
|
register_cpu_notifier(&hrtimers_nb);
|
|
#ifdef CONFIG_HIGH_RES_TIMERS
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|
open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
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|
#endif
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|
}
|
|
|
|
/**
|
|
* schedule_hrtimeout_range - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @delta: slack in expires timeout (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* The @delta argument gives the kernel the freedom to schedule the
|
|
* actual wakeup to a time that is both power and performance friendly.
|
|
* The kernel give the normal best effort behavior for "@expires+@delta",
|
|
* but may decide to fire the timer earlier, but no earlier than @expires.
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
|
|
* pass before the routine returns.
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired otherwise -EINTR
|
|
*/
|
|
int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
struct hrtimer_sleeper t;
|
|
|
|
/*
|
|
* Optimize when a zero timeout value is given. It does not
|
|
* matter whether this is an absolute or a relative time.
|
|
*/
|
|
if (expires && !expires->tv64) {
|
|
__set_current_state(TASK_RUNNING);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* A NULL parameter means "inifinte"
|
|
*/
|
|
if (!expires) {
|
|
schedule();
|
|
__set_current_state(TASK_RUNNING);
|
|
return -EINTR;
|
|
}
|
|
|
|
hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
|
|
hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
|
|
|
|
hrtimer_init_sleeper(&t, current);
|
|
|
|
hrtimer_start_expires(&t.timer, mode);
|
|
if (!hrtimer_active(&t.timer))
|
|
t.task = NULL;
|
|
|
|
if (likely(t.task))
|
|
schedule();
|
|
|
|
hrtimer_cancel(&t.timer);
|
|
destroy_hrtimer_on_stack(&t.timer);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
return !t.task ? 0 : -EINTR;
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
|
|
|
|
/**
|
|
* schedule_hrtimeout - sleep until timeout
|
|
* @expires: timeout value (ktime_t)
|
|
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
|
|
*
|
|
* Make the current task sleep until the given expiry time has
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
|
|
* pass before the routine returns.
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task.
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Returns 0 when the timer has expired otherwise -EINTR
|
|
*/
|
|
int __sched schedule_hrtimeout(ktime_t *expires,
|
|
const enum hrtimer_mode mode)
|
|
{
|
|
return schedule_hrtimeout_range(expires, 0, mode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(schedule_hrtimeout);
|