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 unsigned int len;
42 bool changed, text, rodata, noinstr;
43 };
44
45 struct symbol {
46 struct list_head list;
47 struct rb_node node;
48 struct hlist_node hash;
49 struct hlist_node name_hash;
50 GElf_Sym sym;
51 struct section *sec;
52 char *name;
53 unsigned int idx;
54 unsigned char bind, type;
55 unsigned long offset;
56 unsigned int len;
57 struct symbol *pfunc, *cfunc, *alias;
58 u8 uaccess_safe : 1;
59 u8 static_call_tramp : 1;
60 u8 retpoline_thunk : 1;
61 u8 return_thunk : 1;
62 u8 fentry : 1;
63 u8 kcov : 1;
64 };
65
66 struct reloc {
67 struct list_head list;
68 struct hlist_node hash;
69 union {
70 GElf_Rela rela;
71 GElf_Rel rel;
72 };
73 struct section *sec;
74 struct symbol *sym;
75 unsigned long offset;
76 unsigned int type;
77 s64 addend;
78 int idx;
79 bool jump_table_start;
80 };
81
82 #define ELF_HASH_BITS 20
83
84 struct elf {
85 Elf *elf;
86 GElf_Ehdr ehdr;
87 int fd;
88 bool changed;
89 char *name;
90 struct list_head sections;
91 DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
92 DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
93 DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
94 DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
95 DECLARE_HASHTABLE(reloc_hash, ELF_HASH_BITS);
96 };
97
98 #define OFFSET_STRIDE_BITS 4
99 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
100 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
101
102 #define for_offset_range(_offset, _start, _end) \
103 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
104 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \
105 _offset <= ((_end) & OFFSET_STRIDE_MASK); \
106 _offset += OFFSET_STRIDE)
107
sec_offset_hash(struct section * sec,unsigned long offset)108 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
109 {
110 u32 ol, oh, idx = sec->idx;
111
112 offset &= OFFSET_STRIDE_MASK;
113
114 ol = offset;
115 oh = (offset >> 16) >> 16;
116
117 __jhash_mix(ol, oh, idx);
118
119 return ol;
120 }
121
reloc_hash(struct reloc * reloc)122 static inline u32 reloc_hash(struct reloc *reloc)
123 {
124 return sec_offset_hash(reloc->sec, reloc->offset);
125 }
126
127 struct elf *elf_open_read(const char *name, int flags);
128 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
129
130 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
131 unsigned int type, struct symbol *sym, s64 addend);
132 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
133 unsigned long offset, unsigned int type,
134 struct section *insn_sec, unsigned long insn_off);
135
136 int elf_write_insn(struct elf *elf, struct section *sec,
137 unsigned long offset, unsigned int len,
138 const char *insn);
139 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
140 int elf_write(struct elf *elf);
141 void elf_close(struct elf *elf);
142
143 struct section *find_section_by_name(const struct elf *elf, const char *name);
144 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
145 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
146 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
147 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
148 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
149 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
150 unsigned long offset, unsigned int len);
151 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
152
153 #define for_each_sec(file, sec) \
154 list_for_each_entry(sec, &file->elf->sections, list)
155
156 #endif /* _OBJTOOL_ELF_H */
157