1/*-
2 * Copyright (c) 2008-2010 Rui Paulo <rpaulo@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/types.h>
31#include <elf.h>
32#include <efi.h>
33#include <bootstrap.h>
34
35#ifdef __i386__
36#define ElfW_Rel	Elf32_Rel
37#define	ElfW_Dyn	Elf32_Dyn
38#define	ELFW_R_TYPE	ELF32_R_TYPE
39#elif __amd64__
40#define ElfW_Rel	Elf64_Rel
41#define	ElfW_Dyn	Elf64_Dyn
42#define	ELFW_R_TYPE	ELF64_R_TYPE
43#endif
44
45/*
46 * A simple relocator for IA32/AMD64 EFI binaries.
47 */
48EFI_STATUS
49_reloc(unsigned long ImageBase, ElfW_Dyn *dynamic, EFI_HANDLE image_handle,
50    EFI_SYSTEM_TABLE *system_table)
51{
52	unsigned long relsz, relent;
53	unsigned long *newaddr;
54	ElfW_Rel *rel;
55	ElfW_Dyn *dynp;
56
57	/*
58	 * Find the relocation address, its size and the relocation entry.
59	 */
60	relsz = 0;
61	relent = 0;
62	for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) {
63		switch (dynp->d_tag) {
64		case DT_RELA:
65		case DT_REL:
66			rel = (ElfW_Rel *) ((unsigned long) dynp->d_un.d_ptr +
67			    ImageBase);
68			break;
69		case DT_RELSZ:
70		case DT_RELASZ:
71			relsz = dynp->d_un.d_val;
72			break;
73		case DT_RELENT:
74		case DT_RELAENT:
75			relent = dynp->d_un.d_val;
76			break;
77		default:
78			break;
79		}
80	}
81
82	/*
83	 * Perform the actual relocation.
84	 * XXX: We are reusing code for the amd64 version of this, but
85	 * we must make sure the relocation types are the same.
86	 */
87	CTASSERT(R_386_NONE == R_X86_64_NONE);
88	CTASSERT(R_386_RELATIVE == R_X86_64_RELATIVE);
89	for (; relsz > 0; relsz -= relent) {
90		switch (ELFW_R_TYPE(rel->r_info)) {
91		case R_386_NONE:
92			/* No relocation needs be performed. */
93			break;
94		case R_386_RELATIVE:
95			/* Address relative to the base address. */
96			newaddr = (unsigned long *)(ImageBase + rel->r_offset);
97			*newaddr += ImageBase;
98			break;
99		default:
100			/* XXX: do we need other relocations ? */
101			break;
102		}
103		rel = (ElfW_Rel *) ((caddr_t) rel + relent);
104	}
105
106	return (EFI_SUCCESS);
107}
108