tools/objtool/elf.h

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