tools/objtool/include/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 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         unsigned int text_size;
  87         struct list_head sections;
  88
  89         int symbol_bits;
  90         int symbol_name_bits;
  91         int section_bits;
  92         int section_name_bits;
  93         int reloc_bits;
  94
  95         struct hlist_head *symbol_hash;
  96         struct hlist_head *symbol_name_hash;
  97         struct hlist_head *section_hash;
  98         struct hlist_head *section_name_hash;
  99         struct hlist_head *reloc_hash;
 100 };
 101
 102 #define OFFSET_STRIDE_BITS      4
 103 #define OFFSET_STRIDE           (1UL << OFFSET_STRIDE_BITS)
 104 #define OFFSET_STRIDE_MASK      (~(OFFSET_STRIDE - 1))
 105
 106 #define for_offset_range(_offset, _start, _end)                 \
 107         for (_offset = ((_start) & OFFSET_STRIDE_MASK);         \
 108              _offset >= ((_start) & OFFSET_STRIDE_MASK) &&      \
 109              _offset <= ((_end) & OFFSET_STRIDE_MASK);          \
 110              _offset += OFFSET_STRIDE)
 111
 112 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
 113 {
 114         u32 ol, oh, idx = sec->idx;
 115
 116         offset &= OFFSET_STRIDE_MASK;
 117
 118         ol = offset;
 119         oh = (offset >> 16) >> 16;
 120
 121         __jhash_mix(ol, oh, idx);
 122
 123         return ol;
 124 }
 125
 126 static inline u32 reloc_hash(struct reloc *reloc)
 127 {
 128         return sec_offset_hash(reloc->sec, reloc->offset);
 129 }
 130
 131 struct elf *elf_open_read(const char *name, int flags);
 132 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
 133
 134 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
 135                   unsigned int type, struct symbol *sym, int addend);
 136 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
 137                           unsigned long offset, unsigned int type,
 138                           struct section *insn_sec, unsigned long insn_off);
 139
 140 int elf_write_insn(struct elf *elf, struct section *sec,
 141                    unsigned long offset, unsigned int len,
 142                    const char *insn);
 143 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
 144 struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name);
 145 int elf_write(struct elf *elf);
 146 void elf_close(struct elf *elf);
 147
 148 struct section *find_section_by_name(const struct elf *elf, const char *name);
 149 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
 150 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
 151 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
 152 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
 153 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
 154 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
 155                                      unsigned long offset, unsigned int len);
 156 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
 157
 158 #define for_each_sec(file, sec)                                         \
 159         list_for_each_entry(sec, &file->elf->sections, list)
 160
 161 #endif /* _OBJTOOL_ELF_H */