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