1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5
6 #ifndef _OBJTOOL_ELF_H
7 #define _OBJTOOL_ELF_H
8
9 #include <stdio.h>
10 #include <gelf.h>
11 #include <linux/list.h>
12 #include <linux/hashtable.h>
13 #include <linux/rbtree.h>
14 #include <linux/jhash.h>
15
16 #ifdef LIBELF_USE_DEPRECATED
17 # define elf_getshdrnum elf_getshnum
18 # define elf_getshdrstrndx elf_getshstrndx
19 #endif
20
21 /*
22 * Fallback for systems without this "read, mmaping if possible" cmd.
23 */
24 #ifndef ELF_C_READ_MMAP
25 #define ELF_C_READ_MMAP ELF_C_READ
26 #endif
27
28 struct section {
29 struct list_head list;
30 struct hlist_node hash;
31 struct hlist_node name_hash;
32 GElf_Shdr sh;
33 struct rb_root symbol_tree;
34 struct list_head symbol_list;
35 struct list_head reloc_list;
36 struct section *base, *reloc;
37 struct symbol *sym;
38 Elf_Data *data;
39 char *name;
40 int idx;
41 bool changed, text, rodata, noinstr;
42 };
43
44 struct symbol {
45 struct list_head list;
46 struct rb_node node;
47 struct hlist_node hash;
48 struct hlist_node name_hash;
49 GElf_Sym sym;
50 struct section *sec;
51 char *name;
52 unsigned int idx;
53 unsigned char bind, type;
54 unsigned long offset;
55 unsigned int len;
56 struct symbol *pfunc, *cfunc, *alias;
57 bool uaccess_safe;
58 bool static_call_tramp;
59 };
60
61 struct reloc {
62 struct list_head list;
63 struct hlist_node hash;
64 union {
65 GElf_Rela rela;
66 GElf_Rel rel;
67 };
68 struct section *sec;
69 struct symbol *sym;
70 unsigned long offset;
71 unsigned int type;
72 int addend;
73 int idx;
74 bool jump_table_start;
75 };
76
77 #define ELF_HASH_BITS 20
78
79 struct elf {
80 Elf *elf;
81 GElf_Ehdr ehdr;
82 int fd;
83 bool changed;
84 char *name;
85 unsigned int text_size;
86 struct list_head sections;
87
88 int symbol_bits;
89 int symbol_name_bits;
90 int section_bits;
91 int section_name_bits;
92 int reloc_bits;
93
94 struct hlist_head *symbol_hash;
95 struct hlist_head *symbol_name_hash;
96 struct hlist_head *section_hash;
97 struct hlist_head *section_name_hash;
98 struct hlist_head *reloc_hash;
99 };
100
101 #define OFFSET_STRIDE_BITS 4
102 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
103 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
104
105 #define for_offset_range(_offset, _start, _end) \
106 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
107 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \
108 _offset <= ((_end) & OFFSET_STRIDE_MASK); \
109 _offset += OFFSET_STRIDE)
110
sec_offset_hash(struct section * sec,unsigned long offset)111 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
112 {
113 u32 ol, oh, idx = sec->idx;
114
115 offset &= OFFSET_STRIDE_MASK;
116
117 ol = offset;
118 oh = (offset >> 16) >> 16;
119
120 __jhash_mix(ol, oh, idx);
121
122 return ol;
123 }
124
reloc_hash(struct reloc * reloc)125 static inline u32 reloc_hash(struct reloc *reloc)
126 {
127 return sec_offset_hash(reloc->sec, reloc->offset);
128 }
129
130 struct elf *elf_open_read(const char *name, int flags);
131 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
132
133 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
134 unsigned int type, struct symbol *sym, int addend);
135 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
136 unsigned long offset, unsigned int type,
137 struct section *insn_sec, unsigned long insn_off);
138
139 int elf_write_insn(struct elf *elf, struct section *sec,
140 unsigned long offset, unsigned int len,
141 const char *insn);
142 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
143 struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name);
144 int elf_write(struct elf *elf);
145 void elf_close(struct elf *elf);
146
147 struct section *find_section_by_name(const struct elf *elf, const char *name);
148 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
149 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
150 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
151 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
152 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
153 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
154 unsigned long offset, unsigned int len);
155 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
156
157 #define for_each_sec(file, sec) \
158 list_for_each_entry(sec, &file->elf->sections, list)
159
160 #endif /* _OBJTOOL_ELF_H */
161
