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 u8 uaccess_safe : 1;
58 u8 static_call_tramp : 1;
59 u8 retpoline_thunk : 1;
60 u8 return_thunk : 1;
61 u8 fentry : 1;
62 u8 profiling_func : 1;
63 struct list_head pv_target;
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 unsigned int text_size, num_files;
91 struct list_head sections;
92
93 int symbol_bits;
94 int symbol_name_bits;
95 int section_bits;
96 int section_name_bits;
97 int reloc_bits;
98
99 struct hlist_head *symbol_hash;
100 struct hlist_head *symbol_name_hash;
101 struct hlist_head *section_hash;
102 struct hlist_head *section_name_hash;
103 struct hlist_head *reloc_hash;
104 };
105
106 #define OFFSET_STRIDE_BITS 4
107 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
108 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
109
110 #define for_offset_range(_offset, _start, _end) \
111 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
112 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \
113 _offset <= ((_end) & OFFSET_STRIDE_MASK); \
114 _offset += OFFSET_STRIDE)
115
sec_offset_hash(struct section * sec,unsigned long offset)116 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
117 {
118 u32 ol, oh, idx = sec->idx;
119
120 offset &= OFFSET_STRIDE_MASK;
121
122 ol = offset;
123 oh = (offset >> 16) >> 16;
124
125 __jhash_mix(ol, oh, idx);
126
127 return ol;
128 }
129
reloc_hash(struct reloc * reloc)130 static inline u32 reloc_hash(struct reloc *reloc)
131 {
132 return sec_offset_hash(reloc->sec, reloc->offset);
133 }
134
135 /*
136 * Try to see if it's a whole archive (vmlinux.o or module).
137 *
138 * Note this will miss the case where a module only has one source file.
139 */
has_multiple_files(struct elf * elf)140 static inline bool has_multiple_files(struct elf *elf)
141 {
142 return elf->num_files > 1;
143 }
144
145 struct elf *elf_open_read(const char *name, int flags);
146 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
147
148 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
149 unsigned int type, struct symbol *sym, s64 addend);
150 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
151 unsigned long offset, unsigned int type,
152 struct section *insn_sec, unsigned long insn_off);
153
154 int elf_write_insn(struct elf *elf, struct section *sec,
155 unsigned long offset, unsigned int len,
156 const char *insn);
157 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
158 int elf_write(struct elf *elf);
159 void elf_close(struct elf *elf);
160
161 struct section *find_section_by_name(const struct elf *elf, const char *name);
162 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
163 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
164 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
165 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
166 int find_symbol_hole_containing(const struct section *sec, unsigned long offset);
167 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
168 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
169 unsigned long offset, unsigned int len);
170 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
171
172 #define for_each_sec(file, sec) \
173 list_for_each_entry(sec, &file->elf->sections, list)
174
175 #endif /* _OBJTOOL_ELF_H */
176