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 }; 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 unsigned long __subtree_last; 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 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 }; 108 109 #define OFFSET_STRIDE_BITS 4 110 #define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS) 111 #define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1)) 112 113 #define for_offset_range(_offset, _start, _end) \ 114 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \ 115 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \ 116 _offset <= ((_end) & OFFSET_STRIDE_MASK); \ 117 _offset += OFFSET_STRIDE) 118 119 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset) 120 { 121 u32 ol, oh, idx = sec->idx; 122 123 offset &= OFFSET_STRIDE_MASK; 124 125 ol = offset; 126 oh = (offset >> 16) >> 16; 127 128 __jhash_mix(ol, oh, idx); 129 130 return ol; 131 } 132 133 static inline u32 reloc_hash(struct reloc *reloc) 134 { 135 return sec_offset_hash(reloc->sec, reloc->offset); 136 } 137 138 /* 139 * Try to see if it's a whole archive (vmlinux.o or module). 140 * 141 * Note this will miss the case where a module only has one source file. 142 */ 143 static inline bool has_multiple_files(struct elf *elf) 144 { 145 return elf->num_files > 1; 146 } 147 148 static inline int elf_class_addrsize(struct elf *elf) 149 { 150 if (elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32) 151 return sizeof(u32); 152 else 153 return sizeof(u64); 154 } 155 156 struct elf *elf_open_read(const char *name, int flags); 157 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); 158 159 struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size); 160 161 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, 162 unsigned int type, struct symbol *sym, s64 addend); 163 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, 164 unsigned long offset, unsigned int type, 165 struct section *insn_sec, unsigned long insn_off); 166 167 int elf_write_insn(struct elf *elf, struct section *sec, 168 unsigned long offset, unsigned int len, 169 const char *insn); 170 int elf_write_reloc(struct elf *elf, struct reloc *reloc); 171 int elf_write(struct elf *elf); 172 void elf_close(struct elf *elf); 173 174 struct section *find_section_by_name(const struct elf *elf, const char *name); 175 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset); 176 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset); 177 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name); 178 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset); 179 int find_symbol_hole_containing(const struct section *sec, unsigned long offset); 180 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset); 181 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, 182 unsigned long offset, unsigned int len); 183 struct symbol *find_func_containing(struct section *sec, unsigned long offset); 184 185 #define for_each_sec(file, sec) \ 186 list_for_each_entry(sec, &file->elf->sections, list) 187 188 #endif /* _OBJTOOL_ELF_H */ 189