1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2019 John Baldwin <jhb@FreeBSD.org>
5 *
6 * This software was developed by SRI International and the University of
7 * Cambridge Computer Laboratory (Department of Computer Science and
8 * Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
9 * DARPA SSITH research programme.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/endian.h>
34
35 #include <err.h>
36 #include <errno.h>
37 #include <gelf.h>
38
39 #include "ef.h"
40
41 /*
42 * Apply relocations to the values obtained from the file. `relbase' is the
43 * target relocation address of the section, and `dataoff/len' is the region
44 * that is to be relocated, and has been copied to *dest
45 */
46 static int
ef_mips_reloc(struct elf_file * ef,const void * reldata,Elf_Type reltype,GElf_Addr relbase,GElf_Addr dataoff,size_t len,void * dest)47 ef_mips_reloc(struct elf_file *ef, const void *reldata, Elf_Type reltype,
48 GElf_Addr relbase, GElf_Addr dataoff, size_t len, void *dest)
49 {
50 char *where;
51 GElf_Addr addr, addend;
52 GElf_Size rtype, symidx;
53 const GElf_Rel *rel;
54 const GElf_Rela *rela;
55
56 switch (reltype) {
57 case ELF_T_REL:
58 rel = (const GElf_Rel *)reldata;
59 where = (char *)dest + (relbase + rel->r_offset - dataoff);
60 addend = 0;
61 rtype = GELF_R_TYPE(rel->r_info);
62 symidx = GELF_R_SYM(rel->r_info);
63 break;
64 case ELF_T_RELA:
65 rela = (const GElf_Rela *)reldata;
66 where = (char *)dest + (relbase + rela->r_offset - dataoff);
67 addend = rela->r_addend;
68 rtype = GELF_R_TYPE(rela->r_info);
69 symidx = GELF_R_SYM(rela->r_info);
70 break;
71 default:
72 return (EINVAL);
73 }
74
75 if (where < (char *)dest || where >= (char *)dest + len)
76 return (0);
77
78 if (reltype == ELF_T_REL) {
79 if (elf_class(ef) == ELFCLASS64) {
80 if (elf_encoding(ef) == ELFDATA2LSB)
81 addend = le64dec(where);
82 else
83 addend = be64dec(where);
84 } else {
85 if (elf_encoding(ef) == ELFDATA2LSB)
86 addend = le32dec(where);
87 else
88 addend = be32dec(where);
89 }
90 }
91
92 switch (rtype) {
93 case R_MIPS_64: /* S + A */
94 addr = EF_SYMADDR(ef, symidx) + addend;
95 if (elf_encoding(ef) == ELFDATA2LSB)
96 le64enc(where, addr);
97 else
98 be64enc(where, addr);
99 break;
100 case R_MIPS_32: /* S + A */
101 addr = EF_SYMADDR(ef, symidx) + addend;
102 if (elf_encoding(ef) == ELFDATA2LSB)
103 le32enc(where, addr);
104 else
105 be32enc(where, addr);
106 break;
107 default:
108 warnx("unhandled relocation type %d", (int)rtype);
109 }
110 return (0);
111 }
112
113 ELF_RELOC(ELFCLASS32, ELFDATA2LSB, EM_MIPS, ef_mips_reloc);
114 ELF_RELOC(ELFCLASS32, ELFDATA2MSB, EM_MIPS, ef_mips_reloc);
115 ELF_RELOC(ELFCLASS64, ELFDATA2LSB, EM_MIPS, ef_mips_reloc);
116 ELF_RELOC(ELFCLASS64, ELFDATA2MSB, EM_MIPS, ef_mips_reloc);
117