freebsd-skq/sys/i386/xen/xen_clock_util.c

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/*-
* Copyright (c) 2009 Adrian Chadd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/time.h>
#include <xen/xen_intr.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/pmap.h>
#include <xen/hypervisor.h>
#include <machine/xen/xen-os.h>
#include <machine/xen/xenfunc.h>
#include <xen/interface/io/xenbus.h>
#include <xen/interface/vcpu.h>
#include <machine/cpu.h>
#include <machine/xen/xen_clock_util.h>
/*
* Read the current hypervisor start time (wall clock) from Xen.
*/
void
xen_fetch_wallclock(struct timespec *ts)
{
shared_info_t *s = HYPERVISOR_shared_info;
uint32_t ts_version;
do {
ts_version = s->wc_version;
rmb();
ts->tv_sec = s->wc_sec;
ts->tv_nsec = s->wc_nsec;
rmb();
}
while ((s->wc_version & 1) | (ts_version ^ s->wc_version));
}
/*
* Read the current hypervisor system uptime value from Xen.
*/
void
xen_fetch_uptime(struct timespec *ts)
{
shared_info_t *s = HYPERVISOR_shared_info;
struct vcpu_time_info *src;
struct shadow_time_info dst;
uint32_t pre_version, post_version;
src = &s->vcpu_info[smp_processor_id()].time;
spinlock_enter();
do {
pre_version = dst.version = src->version;
rmb();
dst.system_timestamp = src->system_time;
rmb();
post_version = src->version;
}
while ((pre_version & 1) | (pre_version ^ post_version));
spinlock_exit();
ts->tv_sec = dst.system_timestamp / 1000000000;
ts->tv_nsec = dst.system_timestamp % 1000000000;
}