cfd28f6695
UML's supposed nanosecond clock interacts badly with NTP when NTP decides that the clock has drifted ahead and needs to be slowed down. Slowing down the clock is done by decrementing the cycle-to-nanosecond multiplier, which is 1. Decrementing that gives you 0 and time is stopped. This is fixed by switching to a microsecond clock, with a multiplier of 1000. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
126 lines
2.7 KiB
C
126 lines
2.7 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <linux/clockchips.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/jiffies.h>
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#include <linux/threads.h>
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#include <asm/irq.h>
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#include <asm/param.h>
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#include "kern_util.h"
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#include "os.h"
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/*
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* Scheduler clock - returns current time in nanosec units.
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*/
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unsigned long long sched_clock(void)
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{
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return (unsigned long long)jiffies_64 * (NSEC_PER_SEC / HZ);
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}
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void timer_handler(int sig, struct uml_pt_regs *regs)
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{
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unsigned long flags;
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local_irq_save(flags);
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do_IRQ(TIMER_IRQ, regs);
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local_irq_restore(flags);
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}
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static void itimer_set_mode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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set_interval();
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break;
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case CLOCK_EVT_MODE_SHUTDOWN:
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_ONESHOT:
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disable_timer();
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break;
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case CLOCK_EVT_MODE_RESUME:
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break;
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}
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}
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static int itimer_next_event(unsigned long delta,
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struct clock_event_device *evt)
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{
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return timer_one_shot(delta + 1);
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}
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static struct clock_event_device itimer_clockevent = {
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.name = "itimer",
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.rating = 250,
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.cpumask = CPU_MASK_ALL,
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.set_mode = itimer_set_mode,
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.set_next_event = itimer_next_event,
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.shift = 32,
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.irq = 0,
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};
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static irqreturn_t um_timer(int irq, void *dev)
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{
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(*itimer_clockevent.event_handler)(&itimer_clockevent);
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return IRQ_HANDLED;
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}
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static cycle_t itimer_read(void)
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{
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return os_nsecs() / 1000;
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}
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static struct clocksource itimer_clocksource = {
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.name = "itimer",
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.rating = 300,
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.read = itimer_read,
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.mask = CLOCKSOURCE_MASK(64),
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.mult = 1000,
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.shift = 0,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init setup_itimer(void)
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{
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int err;
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err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
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if (err != 0)
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printk(KERN_ERR "register_timer : request_irq failed - "
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"errno = %d\n", -err);
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itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
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itimer_clockevent.max_delta_ns =
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clockevent_delta2ns(60 * HZ, &itimer_clockevent);
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itimer_clockevent.min_delta_ns =
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clockevent_delta2ns(1, &itimer_clockevent);
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err = clocksource_register(&itimer_clocksource);
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if (err) {
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printk(KERN_ERR "clocksource_register returned %d\n", err);
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return;
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}
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clockevents_register_device(&itimer_clockevent);
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}
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void __init time_init(void)
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{
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long long nsecs;
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timer_init();
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nsecs = os_nsecs();
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set_normalized_timespec(&wall_to_monotonic, -nsecs / NSEC_PER_SEC,
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-nsecs % NSEC_PER_SEC);
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set_normalized_timespec(&xtime, nsecs / NSEC_PER_SEC,
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nsecs % NSEC_PER_SEC);
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late_time_init = setup_itimer;
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}
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