1/*	$OpenBSD: usertc.c,v 1.5 2022/09/22 04:57:07 robert Exp $ */
2/*
3 * Copyright (c) 2020 Paul Irofti <paul@irofti.net>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/types.h>
19#include <sys/timetc.h>
20
21static inline u_int
22rdtsc_lfence(void)
23{
24	uint32_t hi, lo;
25	__asm volatile("lfence; rdtsc" : "=a"(lo), "=d"(hi));
26	return ((uint64_t)lo)|(((uint64_t)hi)<<32);
27}
28
29static inline u_int
30rdtscp(void)
31{
32	uint32_t hi, lo;
33	__asm volatile("rdtscp" : "=a"(lo), "=d"(hi) : : "ecx");
34	return ((uint64_t)lo)|(((uint64_t)hi)<<32);
35}
36
37static int
38tc_get_timecount(struct timekeep *tk, u_int *tc)
39{
40	switch (tk->tk_user) {
41	case TC_TSC_LFENCE:
42		*tc = rdtsc_lfence();
43		return 0;
44	case TC_TSC_RDTSCP:
45		*tc = rdtscp();
46		return 0;
47	}
48
49	return -1;
50}
51
52int (*const _tc_get_timecount)(struct timekeep *, u_int *) = tc_get_timecount;
53