1 /* $OpenBSD: usertc.c,v 1.3 2020/08/23 21:38:47 cheloha 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 21 static inline u_int 22 rdtsc_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 29 static int 30 tc_get_timecount(struct timekeep *tk, u_int *tc) 31 { 32 switch (tk->tk_user) { 33 case TC_TSC: 34 *tc = rdtsc_lfence(); 35 return 0; 36 } 37 38 return -1; 39 } 40 41 int (*const _tc_get_timecount)(struct timekeep *, u_int *) = tc_get_timecount; 42