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         bool changed, text, rodata, noinstr;
  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         struct symbol *pfunc, *cfunc, *alias;
  57         u8 uaccess_safe      : 1;
  58         u8 static_call_tramp : 1;
  59         u8 retpoline_thunk   : 1;
  60         u8 return_thunk      : 1;
  61         u8 fentry            : 1;
  62         u8 kcov              : 1;
  63 };
  64
  65 struct reloc {
  66         struct list_head list;
  67         struct hlist_node hash;
  68         union {
  69                 GElf_Rela rela;
  70                 GElf_Rel  rel;
  71         };
  72         struct section *sec;
  73         struct symbol *sym;
  74         unsigned long offset;
  75         unsigned int type;
  76         s64 addend;
  77         int idx;
  78         bool jump_table_start;
  79 };
  80
  81 #define ELF_HASH_BITS   20
  82
  83 struct elf {
  84         Elf *elf;
  85         GElf_Ehdr ehdr;
  86         int fd;
  87         bool changed;
  88         char *name;
  89         unsigned int text_size;
  90         struct list_head sections;
  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 hlist_head *symbol_hash;
  99         struct hlist_head *symbol_name_hash;
 100         struct hlist_head *section_hash;
 101         struct hlist_head *section_name_hash;
 102         struct hlist_head *reloc_hash;
 103 };
 104
 105 #define OFFSET_STRIDE_BITS      4
 106 #define OFFSET_STRIDE           (1UL << OFFSET_STRIDE_BITS)
 107 #define OFFSET_STRIDE_MASK      (~(OFFSET_STRIDE - 1))
 108
 109 #define for_offset_range(_offset, _start, _end)                 \
 110         for (_offset = ((_start) & OFFSET_STRIDE_MASK);         \
 111              _offset >= ((_start) & OFFSET_STRIDE_MASK) &&      \
 112              _offset <= ((_end) & OFFSET_STRIDE_MASK);          \
 113              _offset += OFFSET_STRIDE)
 114
 115 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
 116 {
 117         u32 ol, oh, idx = sec->idx;
 118
 119         offset &= OFFSET_STRIDE_MASK;
 120
 121         ol = offset;
 122         oh = (offset >> 16) >> 16;
 123
 124         __jhash_mix(ol, oh, idx);
 125
 126         return ol;
 127 }
 128
 129 static inline u32 reloc_hash(struct reloc *reloc)
 130 {
 131         return sec_offset_hash(reloc->sec, reloc->offset);
 132 }
 133
 134 struct elf *elf_open_read(const char *name, int flags);
 135 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
 136
 137 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
 138                   unsigned int type, struct symbol *sym, s64 addend);
 139 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
 140                           unsigned long offset, unsigned int type,
 141                           struct section *insn_sec, unsigned long insn_off);
 142
 143 int elf_write_insn(struct elf *elf, struct section *sec,
 144                    unsigned long offset, unsigned int len,
 145                    const char *insn);
 146 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
 147 int elf_write(struct elf *elf);
 148 void elf_close(struct elf *elf);
 149
 150 struct section *find_section_by_name(const struct elf *elf, const char *name);
 151 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
 152 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
 153 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
 154 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
 155 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
 156 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
 157                                      unsigned long offset, unsigned int len);
 158 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
 159
 160 #define for_each_sec(file, sec)                                         \
 161         list_for_each_entry(sec, &file->elf->sections, list)
 162
 163 #endif /* _OBJTOOL_ELF_H */