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 fentry            : 1;
  61         u8 kcov              : 1;
  62 };
  63
  64 struct reloc {
  65         struct list_head list;
  66         struct hlist_node hash;
  67         union {
  68                 GElf_Rela rela;
  69                 GElf_Rel  rel;
  70         };
  71         struct section *sec;
  72         struct symbol *sym;
  73         unsigned long offset;
  74         unsigned int type;
  75         long addend;
  76         int idx;
  77         bool jump_table_start;
  78 };
  79
  80 #define ELF_HASH_BITS   20
  81
  82 struct elf {
  83         Elf *elf;
  84         GElf_Ehdr ehdr;
  85         int fd;
  86         bool changed;
  87         char *name;
  88         unsigned int text_size;
  89         struct list_head sections;
  90
  91         int symbol_bits;
  92         int symbol_name_bits;
  93         int section_bits;
  94         int section_name_bits;
  95         int reloc_bits;
  96
  97         struct hlist_head *symbol_hash;
  98         struct hlist_head *symbol_name_hash;
  99         struct hlist_head *section_hash;
 100         struct hlist_head *section_name_hash;
 101         struct hlist_head *reloc_hash;
 102 };
 103
 104 #define OFFSET_STRIDE_BITS      4
 105 #define OFFSET_STRIDE           (1UL << OFFSET_STRIDE_BITS)
 106 #define OFFSET_STRIDE_MASK      (~(OFFSET_STRIDE - 1))
 107
 108 #define for_offset_range(_offset, _start, _end)                 \
 109         for (_offset = ((_start) & OFFSET_STRIDE_MASK);         \
 110              _offset >= ((_start) & OFFSET_STRIDE_MASK) &&      \
 111              _offset <= ((_end) & OFFSET_STRIDE_MASK);          \
 112              _offset += OFFSET_STRIDE)
 113
 114 static inline u32 sec_offset_hash(struct section *sec, unsigned long offset)
 115 {
 116         u32 ol, oh, idx = sec->idx;
 117
 118         offset &= OFFSET_STRIDE_MASK;
 119
 120         ol = offset;
 121         oh = (offset >> 16) >> 16;
 122
 123         __jhash_mix(ol, oh, idx);
 124
 125         return ol;
 126 }
 127
 128 static inline u32 reloc_hash(struct reloc *reloc)
 129 {
 130         return sec_offset_hash(reloc->sec, reloc->offset);
 131 }
 132
 133 struct elf *elf_open_read(const char *name, int flags);
 134 struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
 135
 136 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
 137                   unsigned int type, struct symbol *sym, long addend);
 138 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
 139                           unsigned long offset, unsigned int type,
 140                           struct section *insn_sec, unsigned long insn_off);
 141
 142 int elf_write_insn(struct elf *elf, struct section *sec,
 143                    unsigned long offset, unsigned int len,
 144                    const char *insn);
 145 int elf_write_reloc(struct elf *elf, struct reloc *reloc);
 146 int elf_write(struct elf *elf);
 147 void elf_close(struct elf *elf);
 148
 149 struct section *find_section_by_name(const struct elf *elf, const char *name);
 150 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
 151 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
 152 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
 153 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
 154 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
 155 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
 156                                      unsigned long offset, unsigned int len);
 157 struct symbol *find_func_containing(struct section *sec, unsigned long offset);
 158
 159 #define for_each_sec(file, sec)                                         \
 160         list_for_each_entry(sec, &file->elf->sections, list)
 161
 162 #endif /* _OBJTOOL_ELF_H */