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#include <arch/elf.h> 16 17#ifdef LIBELF_USE_DEPRECATED 18# define elf_getshdrnum elf_getshnum 19# define elf_getshdrstrndx elf_getshstrndx 20#endif 21 22/* 23 * Fallback for systems without this "read, mmaping if possible" cmd. 24 */ 25#ifndef ELF_C_READ_MMAP 26#define ELF_C_READ_MMAP ELF_C_READ 27#endif 28 29struct elf_hash_node { 30 struct elf_hash_node *next; 31}; 32 33struct section { 34 struct list_head list; 35 struct elf_hash_node hash; 36 struct elf_hash_node name_hash; 37 GElf_Shdr sh; 38 struct rb_root_cached symbol_tree; 39 struct list_head symbol_list; 40 struct section *base, *rsec; 41 struct symbol *sym; 42 Elf_Data *data; 43 char *name; 44 int idx; 45 bool _changed, text, rodata, noinstr, init, truncate; 46 struct reloc *relocs; 47}; 48 49struct symbol { 50 struct list_head list; 51 struct rb_node node; 52 struct elf_hash_node hash; 53 struct elf_hash_node name_hash; 54 GElf_Sym sym; 55 struct section *sec; 56 char *name; 57 unsigned int idx, len; 58 unsigned long offset; 59 unsigned long __subtree_last; 60 struct symbol *pfunc, *cfunc, *alias; 61 unsigned char bind, type; 62 u8 uaccess_safe : 1; 63 u8 static_call_tramp : 1; 64 u8 retpoline_thunk : 1; 65 u8 return_thunk : 1; 66 u8 fentry : 1; 67 u8 profiling_func : 1; 68 u8 warned : 1; 69 u8 embedded_insn : 1; 70 u8 local_label : 1; 71 struct list_head pv_target; 72 struct reloc *relocs; 73}; 74 75struct reloc { 76 struct elf_hash_node hash; 77 struct section *sec; 78 struct symbol *sym; 79 struct reloc *sym_next_reloc; 80}; 81 82struct elf { 83 Elf *elf; 84 GElf_Ehdr ehdr; 85 int fd; 86 bool changed; 87 char *name; 88 unsigned int num_files; 89 struct list_head sections; 90 unsigned long num_relocs; 91 92 int symbol_bits; 93 int symbol_name_bits; 94 int section_bits; 95 int section_name_bits; 96 int reloc_bits; 97 98 struct elf_hash_node **symbol_hash; 99 struct elf_hash_node **symbol_name_hash; 100 struct elf_hash_node **section_hash; 101 struct elf_hash_node **section_name_hash; 102 struct elf_hash_node **reloc_hash; 103 104 struct section *section_data; 105 struct symbol *symbol_data; 106}; 107 108struct elf *elf_open_read(const char *name, int flags); 109 110struct section *elf_create_section(struct elf *elf, const char *name, 111 size_t entsize, unsigned int nr); 112struct section *elf_create_section_pair(struct elf *elf, const char *name, 113 size_t entsize, unsigned int nr, 114 unsigned int reloc_nr); 115 116struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size); 117 118struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec, 119 unsigned long offset, 120 unsigned int reloc_idx, 121 struct section *insn_sec, 122 unsigned long insn_off); 123 124struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec, 125 unsigned long offset, 126 unsigned int reloc_idx, 127 struct symbol *sym, 128 s64 addend); 129 130int elf_write_insn(struct elf *elf, struct section *sec, 131 unsigned long offset, unsigned int len, 132 const char *insn); 133int elf_write(struct elf *elf); 134void elf_close(struct elf *elf); 135 136struct section *find_section_by_name(const struct elf *elf, const char *name); 137struct symbol *find_func_by_offset(struct section *sec, unsigned long offset); 138struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset); 139struct symbol *find_symbol_by_name(const struct elf *elf, const char *name); 140struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset); 141int find_symbol_hole_containing(const struct section *sec, unsigned long offset); 142struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset); 143struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, 144 unsigned long offset, unsigned int len); 145struct symbol *find_func_containing(struct section *sec, unsigned long offset); 146 147/* 148 * Try to see if it's a whole archive (vmlinux.o or module). 149 * 150 * Note this will miss the case where a module only has one source file. 151 */ 152static inline bool has_multiple_files(struct elf *elf) 153{ 154 return elf->num_files > 1; 155} 156 157static inline size_t elf_addr_size(struct elf *elf) 158{ 159 return elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32 ? 4 : 8; 160} 161 162static inline size_t elf_rela_size(struct elf *elf) 163{ 164 return elf_addr_size(elf) == 4 ? sizeof(Elf32_Rela) : sizeof(Elf64_Rela); 165} 166 167static inline unsigned int elf_data_rela_type(struct elf *elf) 168{ 169 return elf_addr_size(elf) == 4 ? R_DATA32 : R_DATA64; 170} 171 172static inline unsigned int elf_text_rela_type(struct elf *elf) 173{ 174 return elf_addr_size(elf) == 4 ? R_TEXT32 : R_TEXT64; 175} 176 177static inline bool is_reloc_sec(struct section *sec) 178{ 179 return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL; 180} 181 182static inline bool sec_changed(struct section *sec) 183{ 184 return sec->_changed; 185} 186 187static inline void mark_sec_changed(struct elf *elf, struct section *sec, 188 bool changed) 189{ 190 sec->_changed = changed; 191 elf->changed |= changed; 192} 193 194static inline unsigned int sec_num_entries(struct section *sec) 195{ 196 return sec->sh.sh_size / sec->sh.sh_entsize; 197} 198 199static inline unsigned int reloc_idx(struct reloc *reloc) 200{ 201 return reloc - reloc->sec->relocs; 202} 203 204static inline void *reloc_rel(struct reloc *reloc) 205{ 206 struct section *rsec = reloc->sec; 207 208 return rsec->data->d_buf + (reloc_idx(reloc) * rsec->sh.sh_entsize); 209} 210 211static inline bool is_32bit_reloc(struct reloc *reloc) 212{ 213 /* 214 * Elf32_Rel: 8 bytes 215 * Elf32_Rela: 12 bytes 216 * Elf64_Rel: 16 bytes 217 * Elf64_Rela: 24 bytes 218 */ 219 return reloc->sec->sh.sh_entsize < 16; 220} 221 222#define __get_reloc_field(reloc, field) \ 223({ \ 224 is_32bit_reloc(reloc) ? \ 225 ((Elf32_Rela *)reloc_rel(reloc))->field : \ 226 ((Elf64_Rela *)reloc_rel(reloc))->field; \ 227}) 228 229#define __set_reloc_field(reloc, field, val) \ 230({ \ 231 if (is_32bit_reloc(reloc)) \ 232 ((Elf32_Rela *)reloc_rel(reloc))->field = val; \ 233 else \ 234 ((Elf64_Rela *)reloc_rel(reloc))->field = val; \ 235}) 236 237static inline u64 reloc_offset(struct reloc *reloc) 238{ 239 return __get_reloc_field(reloc, r_offset); 240} 241 242static inline void set_reloc_offset(struct elf *elf, struct reloc *reloc, u64 offset) 243{ 244 __set_reloc_field(reloc, r_offset, offset); 245 mark_sec_changed(elf, reloc->sec, true); 246} 247 248static inline s64 reloc_addend(struct reloc *reloc) 249{ 250 return __get_reloc_field(reloc, r_addend); 251} 252 253static inline void set_reloc_addend(struct elf *elf, struct reloc *reloc, s64 addend) 254{ 255 __set_reloc_field(reloc, r_addend, addend); 256 mark_sec_changed(elf, reloc->sec, true); 257} 258 259 260static inline unsigned int reloc_sym(struct reloc *reloc) 261{ 262 u64 info = __get_reloc_field(reloc, r_info); 263 264 return is_32bit_reloc(reloc) ? 265 ELF32_R_SYM(info) : 266 ELF64_R_SYM(info); 267} 268 269static inline unsigned int reloc_type(struct reloc *reloc) 270{ 271 u64 info = __get_reloc_field(reloc, r_info); 272 273 return is_32bit_reloc(reloc) ? 274 ELF32_R_TYPE(info) : 275 ELF64_R_TYPE(info); 276} 277 278static inline void set_reloc_sym(struct elf *elf, struct reloc *reloc, unsigned int sym) 279{ 280 u64 info = is_32bit_reloc(reloc) ? 281 ELF32_R_INFO(sym, reloc_type(reloc)) : 282 ELF64_R_INFO(sym, reloc_type(reloc)); 283 284 __set_reloc_field(reloc, r_info, info); 285 286 mark_sec_changed(elf, reloc->sec, true); 287} 288static inline void set_reloc_type(struct elf *elf, struct reloc *reloc, unsigned int type) 289{ 290 u64 info = is_32bit_reloc(reloc) ? 291 ELF32_R_INFO(reloc_sym(reloc), type) : 292 ELF64_R_INFO(reloc_sym(reloc), type); 293 294 __set_reloc_field(reloc, r_info, info); 295 296 mark_sec_changed(elf, reloc->sec, true); 297} 298 299#define for_each_sec(file, sec) \ 300 list_for_each_entry(sec, &file->elf->sections, list) 301 302#define sec_for_each_sym(sec, sym) \ 303 list_for_each_entry(sym, &sec->symbol_list, list) 304 305#define for_each_sym(file, sym) \ 306 for (struct section *__sec, *__fake = (struct section *)1; \ 307 __fake; __fake = NULL) \ 308 for_each_sec(file, __sec) \ 309 sec_for_each_sym(__sec, sym) 310 311#define for_each_reloc(rsec, reloc) \ 312 for (int __i = 0, __fake = 1; __fake; __fake = 0) \ 313 for (reloc = rsec->relocs; \ 314 __i < sec_num_entries(rsec); \ 315 __i++, reloc++) 316 317#define for_each_reloc_from(rsec, reloc) \ 318 for (int __i = reloc_idx(reloc); \ 319 __i < sec_num_entries(rsec); \ 320 __i++, reloc++) 321 322#define OFFSET_STRIDE_BITS 4 323#define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS) 324#define OFFSET_STRIDE_MASK (~(OFFSET_STRIDE - 1)) 325 326#define for_offset_range(_offset, _start, _end) \ 327 for (_offset = ((_start) & OFFSET_STRIDE_MASK); \ 328 _offset >= ((_start) & OFFSET_STRIDE_MASK) && \ 329 _offset <= ((_end) & OFFSET_STRIDE_MASK); \ 330 _offset += OFFSET_STRIDE) 331 332static inline u32 sec_offset_hash(struct section *sec, unsigned long offset) 333{ 334 u32 ol, oh, idx = sec->idx; 335 336 offset &= OFFSET_STRIDE_MASK; 337 338 ol = offset; 339 oh = (offset >> 16) >> 16; 340 341 __jhash_mix(ol, oh, idx); 342 343 return ol; 344} 345 346static inline u32 reloc_hash(struct reloc *reloc) 347{ 348 return sec_offset_hash(reloc->sec, reloc_offset(reloc)); 349} 350 351#endif /* _OBJTOOL_ELF_H */ 352