062875847d
instructions, if supported both by CPU and kernel. Reviewed by: jhb (previous version) Tested by: pho (previous version) Sponsored by: The FreeBSD Foundation MFC after: 3 weeks Differential revision: https://reviews.freebsd.org/D12023
64 lines
2.1 KiB
C
64 lines
2.1 KiB
C
/*-
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* Copyright (c) 2017 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed by Konstantin Belousov <kib@FreeBSD.org>
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#define IN_RTLD 1
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#include <sys/param.h>
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#undef IN_RTLD
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#include <machine/cpufunc.h>
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#include <machine/specialreg.h>
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#include "amd64_detect_rdfsgsbase.h"
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#include "libc_private.h"
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static int state = RDFSGS_UNKNOWN;
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int
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amd64_detect_rdfsgsbase(void)
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{
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u_int p[4];
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if (__predict_true(state != RDFSGS_UNKNOWN))
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return (state);
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if (__getosreldate() >= P_OSREL_WRFSBASE) {
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do_cpuid(0x0, p);
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if (p[0] >= 0x7) {
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cpuid_count(0x7, 0x0, p);
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if ((p[1] & CPUID_STDEXT_FSGSBASE) != 0) {
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state = RDFSGS_SUPPORTED;
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return (state);
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}
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}
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}
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state = RDFSGS_UNSUPPORTED;
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return (state);
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}
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