1 /*- 2 * Copyright (c) 2021 The FreeBSD Foundation 3 * 4 * This software were developed by Konstantin Belousov <kib@FreeBSD.org> 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/param.h> 30 #include <machine/cpufunc.h> 31 #include <machine/specialreg.h> 32 #include <machine/sysarch.h> 33 #include <x86/ifunc.h> 34 #include <errno.h> 35 #include <sched.h> 36 #include "libc_private.h" 37 38 static int 39 sched_getcpu_sys(void) 40 { 41 return (__sys_sched_getcpu()); 42 } 43 44 static int 45 sched_getcpu_rdpid(void) 46 { 47 register_t res; 48 49 __asm("rdpid %0" : "=r" (res)); 50 return ((int)res); 51 } 52 53 static int 54 sched_getcpu_rdtscp(void) 55 { 56 int res; 57 58 __asm("rdtscp" : "=c" (res) : : "eax", "edx"); 59 return (res); 60 } 61 62 DEFINE_UIFUNC(, int, sched_getcpu, (void)) 63 { 64 u_int amd_feature, cpu_exthigh, p[4]; 65 66 if ((cpu_stdext_feature2 & CPUID_STDEXT2_RDPID) != 0) 67 return (sched_getcpu_rdpid); 68 69 amd_feature = 0; 70 if (cpu_feature != 0) { 71 do_cpuid(0x80000000, p); 72 cpu_exthigh = p[0]; 73 if (cpu_exthigh >= 0x80000001) { 74 do_cpuid(0x80000001, p); 75 amd_feature = p[3]; 76 } 77 } 78 79 return ((amd_feature & AMDID_RDTSCP) == 0 ? 80 sched_getcpu_sys : sched_getcpu_rdtscp); 81 } 82