freebsd-skq/lib/libc/sys/__vdso_gettimeofday.c
Konstantin Belousov 150facd256 Rework the __vdso_* symbols attributes to only make the symbols weak,
but use normal references instead of weak.  This makes the statically
linked binaries to use fast gettimeofday(2) by forcing the linker to
resolve references and providing the neccessary functions.

Reported by:	bde
Tested by:	marius (sparc64)
MFC after:	2 weeks
2013-01-30 12:48:16 +00:00

145 lines
3.7 KiB
C

/*-
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/elf.h>
#include <sys/time.h>
#include <sys/vdso.h>
#include <errno.h>
#include <time.h>
#include <machine/atomic.h>
#include "libc_private.h"
static u_int
tc_delta(const struct vdso_timehands *th)
{
return ((__vdso_gettc(th) - th->th_offset_count) &
th->th_counter_mask);
}
static int
binuptime(struct bintime *bt, struct vdso_timekeep *tk, int abs)
{
struct vdso_timehands *th;
uint32_t curr, gen;
do {
if (!tk->tk_enabled)
return (ENOSYS);
/*
* XXXKIB. The load of tk->tk_current should use
* atomic_load_acq_32 to provide load barrier. But
* since tk points to r/o mapped page, x86
* implementation of atomic_load_acq faults.
*/
curr = tk->tk_current;
rmb();
th = &tk->tk_th[curr];
if (th->th_algo != VDSO_TH_ALGO_1)
return (ENOSYS);
gen = th->th_gen;
*bt = th->th_offset;
bintime_addx(bt, th->th_scale * tc_delta(th));
if (abs)
bintime_add(bt, &th->th_boottime);
/*
* Barrier for load of both tk->tk_current and th->th_gen.
*/
rmb();
} while (curr != tk->tk_current || gen == 0 || gen != th->th_gen);
return (0);
}
static struct vdso_timekeep *tk;
#pragma weak __vdso_gettimeofday
int
__vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
struct bintime bt;
int error;
if (tz != NULL)
return (ENOSYS);
if (tk == NULL) {
error = __vdso_gettimekeep(&tk);
if (error != 0 || tk == NULL)
return (ENOSYS);
}
if (tk->tk_ver != VDSO_TK_VER_CURR)
return (ENOSYS);
error = binuptime(&bt, tk, 1);
if (error != 0)
return (error);
bintime2timeval(&bt, tv);
return (0);
}
#pragma weak __vdso_clock_gettime
int
__vdso_clock_gettime(clockid_t clock_id, struct timespec *ts)
{
struct bintime bt;
int abs, error;
if (tk == NULL) {
error = _elf_aux_info(AT_TIMEKEEP, &tk, sizeof(tk));
if (error != 0 || tk == NULL)
return (ENOSYS);
}
if (tk->tk_ver != VDSO_TK_VER_CURR)
return (ENOSYS);
switch (clock_id) {
case CLOCK_REALTIME:
case CLOCK_REALTIME_PRECISE:
case CLOCK_REALTIME_FAST:
case CLOCK_SECOND:
abs = 1;
break;
case CLOCK_MONOTONIC:
case CLOCK_MONOTONIC_PRECISE:
case CLOCK_MONOTONIC_FAST:
case CLOCK_UPTIME:
case CLOCK_UPTIME_PRECISE:
case CLOCK_UPTIME_FAST:
abs = 0;
break;
default:
return (ENOSYS);
}
error = binuptime(&bt, tk, abs);
if (error != 0)
return (error);
bintime2timespec(&bt, ts);
if (clock_id == CLOCK_SECOND)
ts->tv_nsec = 0;
return (0);
}