ef_amd64.c revision 134362 
1/*-
2 * Copyright (c) 2003 Jake Burkholder.
3 * Copyright 1996-1998 John D. Polstra.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: head/usr.sbin/kldxref/ef_amd64.c 134362 2004-08-27 01:06:57Z iedowse $
28 */
29
30#include <sys/types.h>
31#include <machine/elf.h>
32
33#include <err.h>
34#include <errno.h>
35#include <string.h>
36
37#include "ef.h"
38
39/*
40 * Apply relocations to the values we got from the file.
41 */
42int
43ef_reloc(struct elf_file *ef, const void *data, int type, Elf_Off offset,
44    size_t len, void *dest)
45{
46	Elf64_Addr *where, val;
47	Elf32_Addr *where32, val32;
48	Elf_Addr addend, addr;
49	Elf_Word rtype, symidx;
50	const Elf_Rel *rel;
51	const Elf_Rela *rela;
52
53	switch (type) {
54	case EF_RELOC_REL:
55		rel = (const Elf_Rel *)data;
56		where = (Elf_Addr *)(dest + rel->r_offset - offset);
57		rtype = ELF_R_TYPE(rel->r_info);
58		symidx = ELF_R_SYM(rel->r_info);
59		break;
60	case EF_RELOC_RELA:
61		rela = (const Elf_Rela *)data;
62		where = (Elf_Addr *)(dest + rela->r_offset - offset);
63		addend = rela->r_addend;
64		rtype = ELF_R_TYPE(rela->r_info);
65		symidx = ELF_R_SYM(rela->r_info);
66		break;
67	default:
68		return (EINVAL);
69	}
70
71	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
72		return (0);
73
74	if (type == EF_RELOC_REL) {
75		/* Addend is 32 bit on 32 bit relocs */
76		switch (rtype) {
77		case R_X86_64_PC32:
78		case R_X86_64_32S:
79			addend = *(Elf32_Addr *)where;
80			break;
81		default:
82			addend = *where;
83			break;
84		}
85	}
86
87	switch (rtype) {
88	case R_X86_64_NONE:	/* none */
89		break;
90	case R_X86_64_64:	/* S + A */
91		addr = EF_SYMADDR(ef, symidx);
92		val = addr + addend;
93		*where = val;
94		break;
95	case R_X86_64_32S:	/* S + A sign extend */
96		addr = EF_SYMADDR(ef, symidx);
97		val32 = (Elf32_Addr)(addr + addend);
98		where32 = (Elf32_Addr *)where;
99		*where32 = val32;
100		break;
101	case R_X86_64_GLOB_DAT:	/* S */
102		addr = EF_SYMADDR(ef, symidx);
103		*where = addr;
104		break;
105	case R_X86_64_RELATIVE:	/* B + A */
106		addr = (Elf_Addr)addend;
107		val = addr;
108		*where = val;
109		break;
110	default:
111		warnx("unhandled relocation type %d", (int)rtype);
112	}
113	return (0);
114}
115