1 /*-
2 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD: stable/9/lib/libc/i386/sys/__vdso_gettc.c 246775 2013-02-13 23:25:11Z kib $");
28
29 #include <sys/types.h>
30 #include <sys/elf.h>
31 #include <sys/time.h>
32 #include <sys/vdso.h>
33 #include <machine/cpufunc.h>
34 #include "libc_private.h"
35
36 static u_int
__vdso_gettc_low(const struct vdso_timehands * th)37 __vdso_gettc_low(const struct vdso_timehands *th)
38 {
39 uint32_t rv;
40
41 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0"
42 : "=a" (rv) : "c" (th->th_x86_shift) : "edx");
43 return (rv);
44 }
45
46 #pragma weak __vdso_gettc
47 u_int
__vdso_gettc(const struct vdso_timehands * th)48 __vdso_gettc(const struct vdso_timehands *th)
49 {
50
51 return (th->th_x86_shift > 0 ? __vdso_gettc_low(th) : rdtsc32());
52 }
53
54 #pragma weak __vdso_gettimekeep
55 int
__vdso_gettimekeep(struct vdso_timekeep ** tk)56 __vdso_gettimekeep(struct vdso_timekeep **tk)
57 {
58
59 return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
60 }
61