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