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_cached 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, init, truncate;
42 struct reloc *reloc_data;
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, len;
54 unsigned long offset;
55 unsigned long __subtree_last;
56 struct symbol *pfunc, *cfunc, *alias;
57 unsigned char bind, type;
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 profiling_func : 1;
64 struct list_head pv_target;
65 struct list_head reloc_list;
66 };
67
68 struct reloc {
69 struct list_head list;
70 struct hlist_node hash;
71 union {
72 GElf_Rela rela;
73 GElf_Rel rel;
74 };
75 struct section *sec;
76 struct symbol *sym;
77 struct list_head sym_reloc_entry;
78 unsigned long offset;
79 unsigned int type;
80 s64 addend;
81 int idx;
82 bool jump_table_start;
83 };
84
85 #define ELF_HASH_BITS 20
86
87 struct elf {
88 Elf *elf;
89 GElf_Ehdr ehdr;
90 int fd;
91 bool changed;
92 char *name;
93 unsigned int text_size, num_files;
94 struct list_head sections;
95
96 int symbol_bits;
97 int symbol_name_bits;
98 int section_bits;
99 int section_name_bits;
100 int reloc_bits;
101
102 struct hlist_head *symbol_hash;
103 struct hlist_head *symbol_name_hash;
104 struct hlist_head *section_hash;
105 struct hlist_head *section_name_hash;
106 struct hlist_head *reloc_hash;
107
108 struct section *section_data;
109 struct symbol *symbol_data;
110 };
111
112 #define OFFSET_STRIDE_BITS 4
113 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
114 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1))
115
116 #define for_offset_range(_offset, _start, _end) \
117 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \
118 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \
119 _offset <= ((_end) & OFFSET_STRIDE_MASK); \
120 _offset += OFFSET_STRIDE)
121
sec_offset_hash(struct section * sec,unsigned long offset)122 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
123 {
124 u32 ol, oh, idx = sec->idx;
125
126 offset &= OFFSET_STRIDE_MASK;
127
128 ol = offset;
129 oh = (offset >> 16) >> 16;
130
131 __jhash_mix(ol, oh, idx);
132
133 return ol;
134 }
135
reloc_hash(struct reloc * reloc)136 static inline u32 reloc_hash(struct reloc *reloc)
137 {
138 return sec_offset_hash(reloc->sec, reloc->offset);
139 }
140
141 /*
142 * Try to see if it's a whole archive (vmlinux.o or module).
143 *
144 * Note this will miss the case where a module only has one source file.
145 */
has_multiple_files(struct elf * elf)146 static inline bool has_multiple_files(struct elf *elf)
147 {
148 return elf->num_files > 1;
149 }
150
elf_class_addrsize(struct elf * elf)151 static inline int elf_class_addrsize(struct elf *elf)
152 {
153 if (elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32)
154 return sizeof(u32);
155 else
156 return sizeof(u64);
157 }
158
159 struct elf *elf_open_read(const char *name, int flags);
160 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
161
162 struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);
163
164 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
165 unsigned int type, struct symbol *sym, s64 addend);
166 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
167 unsigned long offset, unsigned int type,
168 struct section *insn_sec, unsigned long insn_off);
169
170 int elf_write_insn(struct elf *elf, struct section *sec,
171 unsigned long offset, unsigned int len,
172 const char *insn);
173 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
174 int elf_write(struct elf *elf);
175 void elf_close(struct elf *elf);
176
177 struct section *find_section_by_name(const struct elf *elf, const char *name);
178 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
179 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
180 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
181 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
182 int find_symbol_hole_containing(const struct section *sec, unsigned long offset);
183 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
184 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
185 unsigned long offset, unsigned int len);
186 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
187
188 #define for_each_sec(file, sec) \
189 list_for_each_entry(sec, &file->elf->sections, list)
190
191 #endif /* _OBJTOOL_ELF_H */
192