xref: /freebsd/lib/libc/csu/amd64/reloc.c (revision ec994981447e8a974426660b5071bc405280af73)
1 /*-
2  * Copyright (c) 2018 The FreeBSD Foundation
3  *
4  * This software was 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  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 #include <machine/specialreg.h>
28 #include <machine/cpufunc.h>
29 
30 static uint32_t cpu_feature, cpu_feature2;
31 static uint32_t cpu_stdext_feature, cpu_stdext_feature2;
32 
33 static void
34 init_cpu_features(void)
35 {
36 	u_int p[4];
37 
38 	do_cpuid(1, p);
39 	cpu_feature = p[3];
40 	cpu_feature2 = p[2];
41 	do_cpuid(0, p);
42 	if (p[0] >= 7) {
43 		cpuid_count(7, 0, p);
44 		cpu_stdext_feature = p[1];
45 		cpu_stdext_feature2 = p[2];
46 	} else {
47 		cpu_stdext_feature = 0;
48 		cpu_stdext_feature2 = 0;
49 	}
50 }
51 
52 static void
53 crt1_handle_rela(const Elf_Rela *r)
54 {
55 	Elf_Addr *ptr, *where, target;
56 
57 	switch (ELF_R_TYPE(r->r_info)) {
58 	case R_X86_64_IRELATIVE:
59 		ptr = (Elf_Addr *)r->r_addend;
60 		where = (Elf_Addr *)r->r_offset;
61 		target = ((Elf_Addr (*)(uint32_t, uint32_t, uint32_t,
62 		    uint32_t))ptr)(cpu_feature, cpu_feature2,
63 		    cpu_stdext_feature, cpu_stdext_feature2);
64 		*where = target;
65 		break;
66 	}
67 }
68