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 u8 embedded_insn : 1;
65 };
66
67 struct reloc {
68 struct list_head list;
69 struct hlist_node hash;
70 union {
71 GElf_Rela rela;
72 GElf_Rel rel;
73 };
74 struct section *sec;
75 struct symbol *sym;
76 unsigned long offset;
77 unsigned int type;
78 s64 addend;
79 int idx;
80 bool jump_table_start;
81 };
82
83 #define ELF_HASH_BITS 20
84
85 struct elf {
86 Elf *elf;
87 GElf_Ehdr ehdr;
88 int fd;
89 bool changed;
90 char *name;
91 struct list_head sections;
92 DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
93 DECLARE_HASHTABLE(symbol_name_hash, ELF_HASH_BITS);
94 DECLARE_HASHTABLE(section_hash, ELF_HASH_BITS);
95 DECLARE_HASHTABLE(section_name_hash, ELF_HASH_BITS);
96 DECLARE_HASHTABLE(reloc_hash, ELF_HASH_BITS);
97 };
98
99 #define OFFSET_STRIDE_BITS 4
100 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
101 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
102
103 #define for_offset_range(_offset, _start, _end) \
104 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
105 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \
106 _offset <= ((_end) & OFFSET_STRIDE_MASK); \
107 _offset += OFFSET_STRIDE)
108
sec_offset_hash(struct section * sec,unsigned long offset)109 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
110 {
111 u32 ol, oh, idx = sec->idx;
112
113 offset &= OFFSET_STRIDE_MASK;
114
115 ol = offset;
116 oh = (offset >> 16) >> 16;
117
118 __jhash_mix(ol, oh, idx);
119
120 return ol;
121 }
122
reloc_hash(struct reloc * reloc)123 static inline u32 reloc_hash(struct reloc *reloc)
124 {
125 return sec_offset_hash(reloc->sec, reloc->offset);
126 }
127
128 struct elf *elf_open_read(const char *name, int flags);
129 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
130
131 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
132 unsigned int type, struct symbol *sym, s64 addend);
133 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
134 unsigned long offset, unsigned int type,
135 struct section *insn_sec, unsigned long insn_off);
136
137 int elf_write_insn(struct elf *elf, struct section *sec,
138 unsigned long offset, unsigned int len,
139 const char *insn);
140 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
141 int elf_write(struct elf *elf);
142 void elf_close(struct elf *elf);
143
144 struct section *find_section_by_name(const struct elf *elf, const char *name);
145 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
146 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
147 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
148 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
149 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
150 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
151 unsigned long offset, unsigned int len);
152 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
153
154 #define for_each_sec(file, sec) \
155 list_for_each_entry(sec, &file->elf->sections, list)
156
157 #endif /* _OBJTOOL_ELF_H */
158