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/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#define VDSO_BUILD /* avoid some shift warnings for -m32 in <asm/page.h> */
#include <linux/time.h>
#include <asm/timex.h>
#include <asm/vdso.h>
#if CHIP_HAS_SPLIT_CYCLE()
static inline cycles_t get_cycles_inline(void)
{
unsigned int high = __insn_mfspr(SPR_CYCLE_HIGH);
unsigned int low = __insn_mfspr(SPR_CYCLE_LOW);
unsigned int high2 = __insn_mfspr(SPR_CYCLE_HIGH);
while (unlikely(high != high2)) {
low = __insn_mfspr(SPR_CYCLE_LOW);
high = high2;
high2 = __insn_mfspr(SPR_CYCLE_HIGH);
}
return (((cycles_t)high) << 32) | low;
}
#define get_cycles get_cycles_inline
#endif
/*
* Find out the vDSO data page address in the process address space.
*/
inline unsigned long get_datapage(void)
{
unsigned long ret;
/* vdso data page located in the 2nd vDSO page. */
asm volatile ("lnk %0" : "=r"(ret));
ret &= ~(PAGE_SIZE - 1);
ret += PAGE_SIZE;
return ret;
}
int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
cycles_t cycles;
unsigned long count, sec, ns;
volatile struct vdso_data *vdso_data;
vdso_data = (struct vdso_data *)get_datapage();
/* The use of the timezone is obsolete, normally tz is NULL. */
if (unlikely(tz != NULL)) {
while (1) {
/* Spin until the update finish. */
count = vdso_data->tz_update_count;
if (count & 1)
continue;
tz->tz_minuteswest = vdso_data->tz_minuteswest;
tz->tz_dsttime = vdso_data->tz_dsttime;
/* Check whether updated, read again if so. */
if (count == vdso_data->tz_update_count)
break;
}
}
if (unlikely(tv == NULL))
return 0;
while (1) {
/* Spin until the update finish. */
count = vdso_data->tb_update_count;
if (count & 1)
continue;
sec = vdso_data->xtime_clock_sec;
cycles = get_cycles() - vdso_data->xtime_tod_stamp;
ns = (cycles * vdso_data->mult) + vdso_data->xtime_clock_nsec;
ns >>= vdso_data->shift;
if (ns >= NSEC_PER_SEC) {
ns -= NSEC_PER_SEC;
sec += 1;
}
/* Check whether updated, read again if so. */
if (count == vdso_data->tb_update_count)
break;
}
tv->tv_sec = sec;
tv->tv_usec = ns / 1000;
return 0;
}
int gettimeofday(struct timeval *tv, struct timezone *tz)
__attribute__((weak, alias("__vdso_gettimeofday")));
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