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: stable/9/usr.sbin/kldxref/ef_amd64.c 252043 2013-06-20 21:19:47Z delphij $
28 */
29
30 #include <sys/types.h>
31 #include <machine/elf.h>
32
33 #include <err.h>
34 #include <errno.h>
35
36 #include "ef.h"
37
38 /*
39 * Apply relocations to the values we got from the file. `relbase' is the
40 * target relocation address of the section, and `dataoff' is the target
41 * relocation address of the data in `dest'.
42 */
43 int
ef_reloc(struct elf_file * ef,const void * reldata,int reltype,Elf_Off relbase,Elf_Off dataoff,size_t len,void * dest)44 ef_reloc(struct elf_file *ef, const void *reldata, int reltype, Elf_Off relbase,
45 Elf_Off dataoff, size_t len, void *dest)
46 {
47 Elf64_Addr *where, val;
48 Elf32_Addr *where32, val32;
49 Elf_Addr addend, addr;
50 Elf_Size rtype, symidx;
51 const Elf_Rel *rel;
52 const Elf_Rela *rela;
53
54 switch (reltype) {
55 case EF_RELOC_REL:
56 rel = (const Elf_Rel *)reldata;
57 where = (Elf_Addr *)(dest + relbase + rel->r_offset - dataoff);
58 addend = 0;
59 rtype = ELF_R_TYPE(rel->r_info);
60 symidx = ELF_R_SYM(rel->r_info);
61 break;
62 case EF_RELOC_RELA:
63 rela = (const Elf_Rela *)reldata;
64 where = (Elf_Addr *)(dest + relbase + rela->r_offset - dataoff);
65 addend = rela->r_addend;
66 rtype = ELF_R_TYPE(rela->r_info);
67 symidx = ELF_R_SYM(rela->r_info);
68 break;
69 default:
70 return (EINVAL);
71 }
72
73 if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
74 return (0);
75
76 if (reltype == EF_RELOC_REL) {
77 /* Addend is 32 bit on 32 bit relocs */
78 switch (rtype) {
79 case R_X86_64_PC32:
80 case R_X86_64_32S:
81 addend = *(Elf32_Addr *)where;
82 break;
83 default:
84 addend = *where;
85 break;
86 }
87 }
88
89 switch (rtype) {
90 case R_X86_64_NONE: /* none */
91 break;
92 case R_X86_64_64: /* S + A */
93 addr = EF_SYMADDR(ef, symidx);
94 val = addr + addend;
95 *where = val;
96 break;
97 case R_X86_64_32S: /* S + A sign extend */
98 addr = EF_SYMADDR(ef, symidx);
99 val32 = (Elf32_Addr)(addr + addend);
100 where32 = (Elf32_Addr *)where;
101 *where32 = val32;
102 break;
103 case R_X86_64_GLOB_DAT: /* S */
104 addr = EF_SYMADDR(ef, symidx);
105 *where = addr;
106 break;
107 case R_X86_64_RELATIVE: /* B + A */
108 addr = (Elf_Addr)addend + relbase;
109 val = addr;
110 *where = val;
111 break;
112 default:
113 warnx("unhandled relocation type %d", (int)rtype);
114 }
115 return (0);
116 }
117