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/* -*- Mode:C; c-basic-offset:4; tab-width:4 -*-
****************************************************************************
* (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
* (C) 2002-2003 - Keir Fraser - University of Cambridge
* (C) 2005 - Grzegorz Milos - Intel Research Cambridge
* (C) 2006 - Robert Kaiser - FH Wiesbaden
****************************************************************************
*
* File: time.c
* Author: Rolf Neugebauer and Keir Fraser
* Changes: Grzegorz Milos
*
* Description: Simple time and timer functions
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <os.h>
#include <traps.h>
#include <types.h>
#include <hypervisor.h>
#include <events.h>
#include <time.h>
#include <lib.h>
/************************************************************************
* Time functions
*************************************************************************/
/* These are peridically updated in shared_info, and then copied here. */
struct shadow_time_info {
u64 tsc_timestamp; /* TSC at last update of time vals. */
u64 system_timestamp; /* Time, in nanosecs, since boot. */
u32 tsc_to_nsec_mul;
u32 tsc_to_usec_mul;
int tsc_shift;
u32 version;
};
static struct timespec shadow_ts;
static u32 shadow_ts_version;
static struct shadow_time_info shadow;
#ifndef rmb
#define rmb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory")
#endif
#define HANDLE_USEC_OVERFLOW(_tv) \
do { \
while ( (_tv)->tv_usec >= 1000000 ) \
{ \
(_tv)->tv_usec -= 1000000; \
(_tv)->tv_sec++; \
} \
} while ( 0 )
static inline int time_values_up_to_date(void)
{
struct vcpu_time_info *src = &HYPERVISOR_shared_info->vcpu_info[0].time;
return (shadow.version == src->version);
}
/*
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
* yielding a 64-bit result.
*/
static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
{
u64 product;
#ifdef __i386__
u32 tmp1, tmp2;
#endif
if ( shift < 0 )
delta >>= -shift;
else
delta <<= shift;
#ifdef __i386__
__asm__ (
"mul %5 ; "
"mov %4,%%eax ; "
"mov %%edx,%4 ; "
"mul %5 ; "
"add %4,%%eax ; "
"xor %5,%5 ; "
"adc %5,%%edx ; "
: "=A" (product), "=r" (tmp1), "=r" (tmp2)
: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
#else
__asm__ (
"mul %%rdx ; shrd $32,%%rdx,%%rax"
: "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
#endif
return product;
}
static unsigned long get_nsec_offset(void)
{
u64 now, delta;
rdtscll(now);
delta = now - shadow.tsc_timestamp;
return scale_delta(delta, shadow.tsc_to_nsec_mul, shadow.tsc_shift);
}
static void get_time_values_from_xen(void)
{
struct vcpu_time_info *src = &HYPERVISOR_shared_info->vcpu_info[0].time;
do {
shadow.version = src->version;
rmb();
shadow.tsc_timestamp = src->tsc_timestamp;
shadow.system_timestamp = src->system_time;
shadow.tsc_to_nsec_mul = src->tsc_to_system_mul;
shadow.tsc_shift = src->tsc_shift;
rmb();
}
while ((src->version & 1) | (shadow.version ^ src->version));
shadow.tsc_to_usec_mul = shadow.tsc_to_nsec_mul / 1000;
}
/* monotonic_clock(): returns # of nanoseconds passed since time_init()
* Note: This function is required to return accurate
* time even in the absence of multiple timer ticks.
*/
u64 monotonic_clock(void)
{
u64 time;
u32 local_time_version;
do {
local_time_version = shadow.version;
rmb();
time = shadow.system_timestamp + get_nsec_offset();
if (!time_values_up_to_date())
get_time_values_from_xen();
rmb();
} while (local_time_version != shadow.version);
return time;
}
static void update_wallclock(void)
{
shared_info_t *s = HYPERVISOR_shared_info;
do {
shadow_ts_version = s->wc_version;
rmb();
shadow_ts.tv_sec = s->wc_sec;
shadow_ts.tv_nsec = s->wc_nsec;
rmb();
}
while ((s->wc_version & 1) | (shadow_ts_version ^ s->wc_version));
}
int gettimeofday(struct timeval *tv, void *tz)
{
u64 nsec = monotonic_clock();
nsec += shadow_ts.tv_nsec;
tv->tv_sec = shadow_ts.tv_sec;
tv->tv_sec += NSEC_TO_SEC(nsec);
tv->tv_usec = NSEC_TO_USEC(nsec % 1000000000UL);
return 0;
}
void block_domain(s_time_t until)
{
struct timeval tv;
gettimeofday(&tv, NULL);
if(monotonic_clock() < until)
{
HYPERVISOR_set_timer_op(until);
HYPERVISOR_sched_op(SCHEDOP_block, 0);
}
}
/*
* Just a dummy
*/
static void timer_handler(evtchn_port_t ev, struct pt_regs *regs, void *ign)
{
get_time_values_from_xen();
update_wallclock();
}
void init_time(void)
{
evtchn_port_t port;
printk("Initialising timer interface\n");
port = bind_virq(VIRQ_TIMER, &timer_handler, NULL);
unmask_evtchn(port);
}
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