summaryrefslogtreecommitdiff
path: root/tools/objtool/elf.h
blob: 6ad759fd778e6066d332053c71d6fab5b0bdcc13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
 */

#ifndef _OBJTOOL_ELF_H
#define _OBJTOOL_ELF_H

#include <stdio.h>
#include <gelf.h>
#include <linux/list.h>
#include <linux/hashtable.h>
#include <linux/rbtree.h>
#include <linux/jhash.h>

#ifdef LIBELF_USE_DEPRECATED
# define elf_getshdrnum    elf_getshnum
# define elf_getshdrstrndx elf_getshstrndx
#endif

/*
 * Fallback for systems without this "read, mmaping if possible" cmd.
 */
#ifndef ELF_C_READ_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif

struct section {
	struct list_head list;
	struct hlist_node hash;
	struct hlist_node name_hash;
	GElf_Shdr sh;
	struct rb_root symbol_tree;
	struct list_head symbol_list;
	struct list_head reloc_list;
	struct section *base, *reloc;
	struct symbol *sym;
	Elf_Data *data;
	char *name;
	int idx;
	unsigned int len;
	bool changed, text, rodata, noinstr;
};

struct symbol {
	struct list_head list;
	struct rb_node node;
	struct hlist_node hash;
	struct hlist_node name_hash;
	GElf_Sym sym;
	struct section *sec;
	char *name;
	unsigned int idx;
	unsigned char bind, type;
	unsigned long offset;
	unsigned int len;
	struct symbol *pfunc, *cfunc, *alias;
	bool uaccess_safe;
};

struct reloc {
	struct list_head list;
	struct hlist_node hash;
	GElf_Rela rela;
	struct section *sec;
	struct symbol *sym;
	unsigned int type;
	unsigned long offset;
	int addend;
	bool jump_table_start;
};

#define ELF_HASH_BITS	20

struct elf {
	Elf *elf;
	GElf_Ehdr ehdr;
	int fd;
	char *name;
	struct list_head sections;
	DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
	DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
	DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
	DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
	DECLARE_HASHTABLE(reloc_hash, ELF_HASH_BITS);
};

#define OFFSET_STRIDE_BITS	4
#define OFFSET_STRIDE		(1UL << OFFSET_STRIDE_BITS)
#define OFFSET_STRIDE_MASK	(~(OFFSET_STRIDE - 1))

#define for_offset_range(_offset, _start, _end)			\
	for (_offset = ((_start) & OFFSET_STRIDE_MASK);		\
	     _offset >= ((_start) & OFFSET_STRIDE_MASK) &&	\
	     _offset <= ((_end) & OFFSET_STRIDE_MASK);		\
	     _offset += OFFSET_STRIDE)

static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
{
	u32 ol, oh, idx = sec->idx;

	offset &= OFFSET_STRIDE_MASK;

	ol = offset;
	oh = (offset >> 16) >> 16;

	__jhash_mix(ol, oh, idx);

	return ol;
}

static inline u32 reloc_hash(struct reloc *reloc)
{
	return sec_offset_hash(reloc->sec, reloc->offset);
}

struct elf *elf_open_read(const char *name, int flags);
struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr);
struct section *elf_create_reloc_section(struct elf *elf, struct section *base);
void elf_add_reloc(struct elf *elf, struct reloc *reloc);
int elf_write(const struct elf *elf);
void elf_close(struct elf *elf);

struct section *find_section_by_name(const struct elf *elf, const char *name);
struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
				     unsigned long offset, unsigned int len);
struct symbol *find_func_containing(struct section *sec, unsigned long offset);
int elf_rebuild_reloc_section(struct section *sec);

#define for_each_sec(file, sec)						\
	list_for_each_entry(sec, &file->elf->sections, list)

#endif /* _OBJTOOL_ELF_H */