__vdso_gettc.c revision 302408 
1/*-
2 * Copyright (c) 2015 The FreeBSD Foundation
3 *
4 * This software was developed by Konstantin Belousov
5 * under sponsorship from the FreeBSD Foundation.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/11/lib/libc/aarch64/sys/__vdso_gettc.c 291937 2015-12-07 12:20:26Z kib $");
31
32#include <sys/types.h>
33#include <sys/elf.h>
34#include <sys/time.h>
35#include <sys/vdso.h>
36#include <machine/cpufunc.h>
37#include "libc_private.h"
38
39static inline uint64_t
40cp15_cntvct_get(void)
41{
42	uint64_t reg;
43
44	__asm __volatile("mrs %0, cntvct_el0" : "=r" (reg));
45	return (reg);
46}
47
48static inline uint64_t
49cp15_cntpct_get(void)
50{
51	uint64_t reg;
52
53	__asm __volatile("mrs %0, cntpct_el0" : "=r" (reg));
54	return (reg);
55}
56
57#pragma weak __vdso_gettc
58u_int
59__vdso_gettc(const struct vdso_timehands *th)
60{
61	uint64_t val;
62
63	__asm __volatile("isb" : : : "memory");
64	val = th->th_physical == 0 ? cp15_cntvct_get() : cp15_cntpct_get();
65	return (val);
66}
67
68#pragma weak __vdso_gettimekeep
69int
70__vdso_gettimekeep(struct vdso_timekeep **tk)
71{
72
73	return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
74}
75