xref: /freebsd/lib/libsys/amd64/amd64_set_fsbase.c (revision 4bc66c0f9f2c349af86cbf4e77f000b49d819fea)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2003 Peter Wemm
5  * Copyright (c) 2017, 2018 The FreeBSD Foundation
6  * All rights reserved.
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 
33 #define _WANT_P_OSREL
34 #include <sys/param.h>
35 #include <machine/cpufunc.h>
36 #include <machine/specialreg.h>
37 #include <machine/sysarch.h>
38 #include <x86/ifunc.h>
39 #include "libc_private.h"
40 
41 static int
amd64_set_fsbase_cpu(void * addr)42 amd64_set_fsbase_cpu(void *addr)
43 {
44 
45 	wrfsbase((uintptr_t)addr);
46 	return (0);
47 }
48 
49 static int
amd64_set_fsbase_syscall(void * addr)50 amd64_set_fsbase_syscall(void *addr)
51 {
52 
53 	return (sysarch(AMD64_SET_FSBASE, &addr));
54 }
55 
56 DEFINE_UIFUNC(, int, amd64_set_fsbase, (void *))
57 {
58 
59 	if (__getosreldate() >= P_OSREL_WRFSBASE &&
60 	    (cpu_stdext_feature & CPUID_STDEXT_FSGSBASE) != 0)
61 		return (amd64_set_fsbase_cpu);
62 	return (amd64_set_fsbase_syscall);
63 }
64