xref: /linux/fs/compat_binfmt_elf.c (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9)
1 /*
2  * 32-bit compatibility support for ELF format executables and core dumps.
3  *
4  * Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
5  *
6  * This copyrighted material is made available to anyone wishing to use,
7  * modify, copy, or redistribute it subject to the terms and conditions
8  * of the GNU General Public License v.2.
9  *
10  * Red Hat Author: Roland McGrath.
11  *
12  * This file is used in a 64-bit kernel that wants to support 32-bit ELF.
13  * asm/elf.h is responsible for defining the compat_* and COMPAT_* macros
14  * used below, with definitions appropriate for 32-bit ABI compatibility.
15  *
16  * We use macros to rename the ABI types and machine-dependent
17  * functions used in binfmt_elf.c to compat versions.
18  */
19 
20 #include <linux/elfcore-compat.h>
21 #include <linux/time.h>
22 
23 /*
24  * Rename the basic ELF layout types to refer to the 32-bit class of files.
25  */
26 #undef	ELF_CLASS
27 #define ELF_CLASS	ELFCLASS32
28 
29 #undef	elfhdr
30 #undef	elf_phdr
31 #undef	elf_note
32 #undef	elf_addr_t
33 #define elfhdr		elf32_hdr
34 #define elf_phdr	elf32_phdr
35 #define elf_note	elf32_note
36 #define elf_addr_t	Elf32_Addr
37 
38 /*
39  * The machine-dependent core note format types are defined in elfcore-compat.h,
40  * which requires asm/elf.h to define compat_elf_gregset_t et al.
41  */
42 #define elf_prstatus	compat_elf_prstatus
43 #define elf_prpsinfo	compat_elf_prpsinfo
44 
45 /*
46  * Compat version of cputime_to_compat_timeval, perhaps this
47  * should be an inline in <linux/compat.h>.
48  */
49 static void cputime_to_compat_timeval(const cputime_t cputime,
50 				      struct compat_timeval *value)
51 {
52 	struct timeval tv;
53 	cputime_to_timeval(cputime, &tv);
54 	value->tv_sec = tv.tv_sec;
55 	value->tv_usec = tv.tv_usec;
56 }
57 
58 #undef cputime_to_timeval
59 #define cputime_to_timeval cputime_to_compat_timeval
60 
61 
62 /*
63  * To use this file, asm/elf.h must define compat_elf_check_arch.
64  * The other following macros can be defined if the compat versions
65  * differ from the native ones, or omitted when they match.
66  */
67 
68 #undef	ELF_ARCH
69 #undef	elf_check_arch
70 #define	elf_check_arch	compat_elf_check_arch
71 
72 #ifdef	COMPAT_ELF_PLATFORM
73 #undef	ELF_PLATFORM
74 #define	ELF_PLATFORM		COMPAT_ELF_PLATFORM
75 #endif
76 
77 #ifdef	COMPAT_ELF_HWCAP
78 #undef	ELF_HWCAP
79 #define	ELF_HWCAP		COMPAT_ELF_HWCAP
80 #endif
81 
82 #ifdef	COMPAT_ARCH_DLINFO
83 #undef	ARCH_DLINFO
84 #define	ARCH_DLINFO		COMPAT_ARCH_DLINFO
85 #endif
86 
87 #ifdef	COMPAT_ELF_ET_DYN_BASE
88 #undef	ELF_ET_DYN_BASE
89 #define	ELF_ET_DYN_BASE		COMPAT_ELF_ET_DYN_BASE
90 #endif
91 
92 #ifdef COMPAT_ELF_EXEC_PAGESIZE
93 #undef	ELF_EXEC_PAGESIZE
94 #define	ELF_EXEC_PAGESIZE	COMPAT_ELF_EXEC_PAGESIZE
95 #endif
96 
97 #ifdef	COMPAT_ELF_PLAT_INIT
98 #undef	ELF_PLAT_INIT
99 #define	ELF_PLAT_INIT		COMPAT_ELF_PLAT_INIT
100 #endif
101 
102 #ifdef	COMPAT_SET_PERSONALITY
103 #undef	SET_PERSONALITY
104 #define	SET_PERSONALITY		COMPAT_SET_PERSONALITY
105 #endif
106 
107 #ifdef	compat_start_thread
108 #undef	start_thread
109 #define	start_thread		compat_start_thread
110 #endif
111 
112 #ifdef	compat_arch_setup_additional_pages
113 #undef	ARCH_HAS_SETUP_ADDITIONAL_PAGES
114 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
115 #undef	arch_setup_additional_pages
116 #define	arch_setup_additional_pages compat_arch_setup_additional_pages
117 #endif
118 
119 /*
120  * Rename a few of the symbols that binfmt_elf.c will define.
121  * These are all local so the names don't really matter, but it
122  * might make some debugging less confusing not to duplicate them.
123  */
124 #define elf_format		compat_elf_format
125 #define init_elf_binfmt		init_compat_elf_binfmt
126 #define exit_elf_binfmt		exit_compat_elf_binfmt
127 
128 /*
129  * We share all the actual code with the native (64-bit) version.
130  */
131 #include "binfmt_elf.c"
132