ef_amd64.c revision 153504 
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 153504 2005-12-18 04:52:37Z marcel $
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. `relbase' is the
41 * target relocation address of the section, and `dataoff' is the target
42 * relocation address of the data in `dest'.
43 */
44int
45ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
46    Elf_Off dataoff, size_t len, void *dest)
47{
48	Elf64_Addr *where, val;
49	Elf32_Addr *where32, val32;
50	Elf_Addr addend, addr;
51	Elf_Size rtype, symidx;
52	const Elf_Rel *rel;
53	const Elf_Rela *rela;
54
55	switch (reltype) {
56	case EF_RELOC_REL:
57		rel = (const Elf_Rel *)reldata;
58		where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
59		addend = 0;
60		rtype = ELF_R_TYPE(rel->r_info);
61		symidx = ELF_R_SYM(rel->r_info);
62		break;
63	case EF_RELOC_RELA:
64		rela = (const Elf_Rela *)reldata;
65		where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
66		addend = rela->r_addend;
67		rtype = ELF_R_TYPE(rela->r_info);
68		symidx = ELF_R_SYM(rela->r_info);
69		break;
70	default:
71		return (EINVAL);
72	}
73
74	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
75		return (0);
76
77	if (reltype == EF_RELOC_REL) {
78		/* Addend is 32 bit on 32 bit relocs */
79		switch (rtype) {
80		case R_X86_64_PC32:
81		case R_X86_64_32S:
82			addend = *(Elf32_Addr *)where;
83			break;
84		default:
85			addend = *where;
86			break;
87		}
88	}
89
90	switch (rtype) {
91	case R_X86_64_NONE:	/* none */
92		break;
93	case R_X86_64_64:	/* S + A */
94		addr = EF_SYMADDR(ef, symidx);
95		val = addr + addend;
96		*where = val;
97		break;
98	case R_X86_64_32S:	/* S + A sign extend */
99		addr = EF_SYMADDR(ef, symidx);
100		val32 = (Elf32_Addr)(addr + addend);
101		where32 = (Elf32_Addr *)where;
102		*where32 = val32;
103		break;
104	case R_X86_64_GLOB_DAT:	/* S */
105		addr = EF_SYMADDR(ef, symidx);
106		*where = addr;
107		break;
108	case R_X86_64_RELATIVE:	/* B + A */
109		addr = (Elf_Addr)addend + relbase;
110		val = addr;
111		*where = val;
112		break;
113	default:
114		warnx("unhandled relocation type %d", (int)rtype);
115	}
116	return (0);
117}
118