xref: /freebsd/lib/libc/csu/amd64/reloc.c (revision 0303938539f3f12da65128fc67f883efe82dc125)
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 __FBSDID("$FreeBSD$");
28 
29 #include <machine/specialreg.h>
30 #include <machine/cpufunc.h>
31 
32 static uint32_t cpu_feature, cpu_feature2;
33 static uint32_t cpu_stdext_feature, cpu_stdext_feature2;
34 
35 static void
36 init_cpu_features(void)
37 {
38 	u_int p[4];
39 
40 	do_cpuid(1, p);
41 	cpu_feature = p[3];
42 	cpu_feature2 = p[2];
43 	do_cpuid(0, p);
44 	if (p[0] >= 7) {
45 		cpuid_count(7, 0, p);
46 		cpu_stdext_feature = p[1];
47 		cpu_stdext_feature2 = p[2];
48 	} else {
49 		cpu_stdext_feature = 0;
50 		cpu_stdext_feature2 = 0;
51 	}
52 }
53 
54 static void
55 crt1_handle_rela(const Elf_Rela *r)
56 {
57 	Elf_Addr *ptr, *where, target;
58 
59 	switch (ELF_R_TYPE(r->r_info)) {
60 	case R_X86_64_IRELATIVE:
61 		ptr = (Elf_Addr *)r->r_addend;
62 		where = (Elf_Addr *)r->r_offset;
63 		target = ((Elf_Addr (*)(uint32_t, uint32_t, uint32_t,
64 		    uint32_t))ptr)(cpu_feature, cpu_feature2,
65 		    cpu_stdext_feature, cpu_stdext_feature2);
66 		*where = target;
67 		break;
68 	}
69 }
70