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/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include "linux/interrupt.h"
#include "linux/jiffies.h"
#include "linux/threads.h"
#include "asm/irq.h"
#include "asm/param.h"
#include "kern_util.h"
#include "os.h"
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return (unsigned long long)jiffies_64 * (1000000000 / HZ);
}
#ifdef CONFIG_UML_REAL_TIME_CLOCK
static unsigned long long prev_nsecs[NR_CPUS];
static long long delta[NR_CPUS]; /* Deviation per interval */
#endif
void timer_irq(struct uml_pt_regs *regs)
{
unsigned long long ticks = 0;
#ifdef CONFIG_UML_REAL_TIME_CLOCK
int c = cpu();
if (prev_nsecs[c]) {
/* We've had 1 tick */
unsigned long long nsecs = os_nsecs();
delta[c] += nsecs - prev_nsecs[c];
prev_nsecs[c] = nsecs;
/* Protect against the host clock being set backwards */
if (delta[c] < 0)
delta[c] = 0;
ticks += (delta[c] * HZ) / BILLION;
delta[c] -= (ticks * BILLION) / HZ;
}
else prev_nsecs[c] = os_nsecs();
#else
ticks = 1;
#endif
while (ticks > 0) {
do_IRQ(TIMER_IRQ, regs);
ticks--;
}
}
/* Protects local_offset */
static DEFINE_SPINLOCK(timer_spinlock);
static unsigned long long local_offset = 0;
static inline unsigned long long get_time(void)
{
unsigned long long nsecs;
unsigned long flags;
spin_lock_irqsave(&timer_spinlock, flags);
nsecs = os_nsecs();
nsecs += local_offset;
spin_unlock_irqrestore(&timer_spinlock, flags);
return nsecs;
}
irqreturn_t um_timer(int irq, void *dev)
{
unsigned long long nsecs;
unsigned long flags;
write_seqlock_irqsave(&xtime_lock, flags);
do_timer(1);
#ifdef CONFIG_UML_REAL_TIME_CLOCK
nsecs = get_time();
#else
nsecs = (unsigned long long) xtime.tv_sec * BILLION + xtime.tv_nsec +
BILLION / HZ;
#endif
xtime.tv_sec = nsecs / NSEC_PER_SEC;
xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC;
write_sequnlock_irqrestore(&xtime_lock, flags);
return IRQ_HANDLED;
}
static void register_timer(void)
{
int err;
timer_init();
err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
if (err != 0)
printk(KERN_ERR "register_timer : request_irq failed - "
"errno = %d\n", -err);
err = set_interval();
if (err != 0)
printk(KERN_ERR "register_timer : set_interval failed - "
"errno = %d\n", -err);
}
extern void (*late_time_init)(void);
void time_init(void)
{
long long nsecs;
nsecs = os_nsecs();
set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
-nsecs % BILLION);
set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);
late_time_init = register_timer;
}
void do_gettimeofday(struct timeval *tv)
{
#ifdef CONFIG_UML_REAL_TIME_CLOCK
unsigned long long nsecs = get_time();
#else
unsigned long long nsecs = (unsigned long long) xtime.tv_sec * BILLION +
xtime.tv_nsec;
#endif
tv->tv_sec = nsecs / NSEC_PER_SEC;
/*
* Careful about calculations here - this was originally done as
* (nsecs - tv->tv_sec * NSEC_PER_SEC) / NSEC_PER_USEC
* which gave bogus (> 1000000) values. Dunno why, suspect gcc
* (4.0.0) miscompiled it, or there's a subtle 64/32-bit conversion
* problem that I missed.
*/
nsecs -= tv->tv_sec * NSEC_PER_SEC;
tv->tv_usec = (unsigned long) nsecs / NSEC_PER_USEC;
}
static inline void set_time(unsigned long long nsecs)
{
unsigned long long now;
unsigned long flags;
spin_lock_irqsave(&timer_spinlock, flags);
now = os_nsecs();
local_offset = nsecs - now;
spin_unlock_irqrestore(&timer_spinlock, flags);
clock_was_set();
}
int do_settimeofday(struct timespec *tv)
{
set_time((unsigned long long) tv->tv_sec * NSEC_PER_SEC + tv->tv_nsec);
return 0;
}
void timer_handler(int sig, struct uml_pt_regs *regs)
{
if (current_thread->cpu == 0)
timer_irq(regs);
local_irq_disable();
irq_enter();
update_process_times(regs->is_user);
irq_exit();
local_irq_enable();
}
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