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20011694 | 1 | /* dl-x86_64.c - arch-dependent part of loadable module support */ |
2 | /* | |
3 | * GRUB -- GRand Unified Bootloader | |
58bc8bd5 | 4 | * Copyright (C) 2002,2005,2007,2009 Free Software Foundation, Inc. |
20011694 | 5 | * |
6 | * GRUB is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * GRUB is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with GRUB. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <grub/dl.h> | |
21 | #include <grub/elf.h> | |
22 | #include <grub/misc.h> | |
23 | #include <grub/err.h> | |
24 | ||
25 | /* Check if EHDR is a valid ELF header. */ | |
26 | grub_err_t | |
27 | grub_arch_dl_check_header (void *ehdr) | |
28 | { | |
29 | Elf64_Ehdr *e = ehdr; | |
30 | ||
31 | /* Check the magic numbers. */ | |
32 | if (e->e_ident[EI_CLASS] != ELFCLASS64 | |
33 | || e->e_ident[EI_DATA] != ELFDATA2LSB | |
34 | || e->e_machine != EM_X86_64) | |
35 | return grub_error (GRUB_ERR_BAD_OS, "invalid arch specific ELF magic"); | |
36 | ||
37 | return GRUB_ERR_NONE; | |
38 | } | |
39 | ||
40 | /* Relocate symbols. */ | |
41 | grub_err_t | |
42 | grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr) | |
43 | { | |
44 | Elf64_Ehdr *e = ehdr; | |
45 | Elf64_Shdr *s; | |
20011694 | 46 | Elf64_Word entsize; |
47 | unsigned i; | |
48 | ||
49 | /* Find a symbol table. */ | |
50 | for (i = 0, s = (Elf64_Shdr *) ((char *) e + e->e_shoff); | |
51 | i < e->e_shnum; | |
52 | i++, s = (Elf64_Shdr *) ((char *) s + e->e_shentsize)) | |
53 | if (s->sh_type == SHT_SYMTAB) | |
54 | break; | |
55 | ||
56 | if (i == e->e_shnum) | |
57 | return grub_error (GRUB_ERR_BAD_MODULE, "no symtab found"); | |
58 | ||
20011694 | 59 | entsize = s->sh_entsize; |
60 | ||
61 | for (i = 0, s = (Elf64_Shdr *) ((char *) e + e->e_shoff); | |
62 | i < e->e_shnum; | |
63 | i++, s = (Elf64_Shdr *) ((char *) s + e->e_shentsize)) | |
64 | if (s->sh_type == SHT_RELA) | |
65 | { | |
66 | grub_dl_segment_t seg; | |
67 | ||
68 | /* Find the target segment. */ | |
69 | for (seg = mod->segment; seg; seg = seg->next) | |
70 | if (seg->section == s->sh_info) | |
71 | break; | |
72 | ||
73 | if (seg) | |
74 | { | |
75 | Elf64_Rela *rel, *max; | |
76 | ||
77 | for (rel = (Elf64_Rela *) ((char *) e + s->sh_offset), | |
78 | max = rel + s->sh_size / s->sh_entsize; | |
79 | rel < max; | |
80 | rel++) | |
81 | { | |
82 | Elf64_Word *addr32; | |
83 | Elf64_Xword *addr64; | |
84 | Elf64_Sym *sym; | |
85 | ||
86 | if (seg->size < rel->r_offset) | |
87 | return grub_error (GRUB_ERR_BAD_MODULE, | |
88 | "reloc offset is out of the segment"); | |
89 | ||
90 | addr32 = (Elf64_Word *) ((char *) seg->addr + rel->r_offset); | |
91 | addr64 = (Elf64_Xword *) addr32; | |
8231fb77 | 92 | sym = (Elf64_Sym *) ((char *) mod->symtab |
32622956 | 93 | + entsize * ELF_R_SYM (rel->r_info)); |
20011694 | 94 | |
32622956 | 95 | switch (ELF_R_TYPE (rel->r_info)) |
20011694 | 96 | { |
97 | case R_X86_64_64: | |
6e09b8b7 | 98 | *addr64 += rel->r_addend + sym->st_value; |
20011694 | 99 | break; |
100 | ||
101 | case R_X86_64_PC32: | |
6e09b8b7 | 102 | *addr32 += rel->r_addend + sym->st_value - |
20011694 | 103 | (Elf64_Xword) seg->addr - rel->r_offset; |
104 | break; | |
105 | ||
106 | case R_X86_64_32: | |
107 | case R_X86_64_32S: | |
6e09b8b7 | 108 | *addr32 += rel->r_addend + sym->st_value; |
20011694 | 109 | break; |
110 | ||
111 | default: | |
9bb182f3 VS |
112 | return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, |
113 | "this relocation (%d) is not implemented yet", | |
114 | ELF_R_TYPE (rel->r_info)); | |
20011694 | 115 | } |
116 | } | |
117 | } | |
118 | } | |
119 | ||
120 | return GRUB_ERR_NONE; | |
121 | } |