1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 5 * Copyright (c) 2016, 2017, 2019 The FreeBSD Foundation 6 * Copyright (c) 2021 Dmitry Chagin <dchagin@FreeBSD.org> 7 * 8 * Portions of this software were developed by Konstantin Belousov 9 * under sponsorship from the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33static inline u_int 34rdtsc_low(const struct vdso_timehands *th) 35{ 36 u_int rv; 37 38 __asm __volatile("rdtsc; shrd %%cl, %%edx, %0" 39 : "=a" (rv) : "c" (th->th_x86_shift) : "edx"); 40 return (rv); 41} 42 43static inline u_int 44rdtscp_low(const struct vdso_timehands *th) 45{ 46 u_int rv; 47 48 __asm __volatile("rdtscp; movl %%edi,%%ecx; shrd %%cl, %%edx, %0" 49 : "=a" (rv) : "D" (th->th_x86_shift) : "ecx", "edx"); 50 return (rv); 51} 52 53static u_int 54rdtsc_low_mb_lfence(const struct vdso_timehands *th) 55{ 56 lfence(); 57 return (rdtsc_low(th)); 58} 59 60static u_int 61rdtsc_low_mb_mfence(const struct vdso_timehands *th) 62{ 63 mfence(); 64 return (rdtsc_low(th)); 65} 66 67static u_int 68rdtsc_low_mb_none(const struct vdso_timehands *th) 69{ 70 return (rdtsc_low(th)); 71} 72 73static u_int 74rdtsc32_mb_lfence(void) 75{ 76 lfence(); 77 return (rdtsc32()); 78} 79 80static u_int 81rdtsc32_mb_mfence(void) 82{ 83 mfence(); 84 return (rdtsc32()); 85} 86 87static u_int 88rdtsc32_mb_none(void) 89{ 90 return (rdtsc32()); 91} 92 93static u_int 94rdtscp32_(void) 95{ 96 return (rdtscp32()); 97} 98 99struct tsc_selector_tag { 100 u_int (*ts_rdtsc32)(void); 101 u_int (*ts_rdtsc_low)(const struct vdso_timehands *); 102}; 103 104static const struct tsc_selector_tag tsc_selector[] = { 105 [0] = { /* Intel, LFENCE */ 106 .ts_rdtsc32 = rdtsc32_mb_lfence, 107 .ts_rdtsc_low = rdtsc_low_mb_lfence, 108 }, 109 [1] = { /* AMD, MFENCE */ 110 .ts_rdtsc32 = rdtsc32_mb_mfence, 111 .ts_rdtsc_low = rdtsc_low_mb_mfence, 112 }, 113 [2] = { /* No SSE2 */ 114 .ts_rdtsc32 = rdtsc32_mb_none, 115 .ts_rdtsc_low = rdtsc_low_mb_none, 116 }, 117 [3] = { /* RDTSCP */ 118 .ts_rdtsc32 = rdtscp32_, 119 .ts_rdtsc_low = rdtscp_low, 120 }, 121}; 122 123static u_int 124__vdso_gettc_rdtsc_low(const struct vdso_timehands *th) 125{ 126 127 return (tsc_selector[kern_tsc_selector].ts_rdtsc_low(th)); 128} 129 130static u_int 131__vdso_gettc_rdtsc32(void) 132{ 133 134 return (tsc_selector[kern_tsc_selector].ts_rdtsc32()); 135} 136 137int 138__vdso_gettc(const struct vdso_timehands *th, u_int *tc) 139{ 140 141 switch (th->th_algo) { 142 case VDSO_TH_ALGO_X86_TSC: 143 *tc = th->th_x86_shift > 0 ? __vdso_gettc_rdtsc_low(th) : 144 __vdso_gettc_rdtsc32(); 145 return (0); 146 case VDSO_TH_ALGO_X86_HPET: 147 /* TODO */ 148 default: 149 return (ENOSYS); 150 } 151} 152