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 */
46static int
47ef_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
113ELF_RELOC(ELFCLASS32, ELFDATA2LSB, EM_MIPS, ef_mips_reloc);
114ELF_RELOC(ELFCLASS32, ELFDATA2MSB, EM_MIPS, ef_mips_reloc);
115ELF_RELOC(ELFCLASS64, ELFDATA2LSB, EM_MIPS, ef_mips_reloc);
116ELF_RELOC(ELFCLASS64, ELFDATA2MSB, EM_MIPS, ef_mips_reloc);
117