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