1 /* AArch64 specific symbolic name handling.
2 Copyright (C) 2013, 2015, 2017 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifdef HAVE_CONFIG_H
30 # include <config.h>
31 #endif
32
33 #include <system.h>
34
35 #include <elf.h>
36 #include <stddef.h>
37 #include <string.h>
38
39 #define BACKEND aarch64_
40 #include "libebl_CPU.h"
41
42
43 /* Check for the simple reloc types. */
44 Elf_Type
aarch64_reloc_simple_type(Ebl * ebl,int type,int * addsub)45 aarch64_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type,
46 int *addsub __attribute__ ((unused)))
47 {
48 switch (type)
49 {
50 case R_AARCH64_ABS64:
51 return ELF_T_XWORD;
52 case R_AARCH64_ABS32:
53 return ELF_T_WORD;
54 case R_AARCH64_ABS16:
55 return ELF_T_HALF;
56
57 default:
58 return ELF_T_NUM;
59 }
60 }
61
62 /* If this is the _GLOBAL_OFFSET_TABLE_ symbol, then it should point in
63 the .got even if there is a .got.plt section.
64 https://sourceware.org/ml/libc-ports/2013-06/msg00057.html
65 https://bugzilla.redhat.com/show_bug.cgi?id=1201778
66 */
67 bool
aarch64_check_special_symbol(Elf * elf,const GElf_Sym * sym,const char * name,const GElf_Shdr * destshdr)68 aarch64_check_special_symbol (Elf *elf, const GElf_Sym *sym,
69 const char *name, const GElf_Shdr *destshdr)
70 {
71 if (name != NULL
72 && strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
73 {
74 size_t shstrndx;
75 if (elf_getshdrstrndx (elf, &shstrndx) != 0)
76 return false;
77 const char *sname = elf_strptr (elf, shstrndx, destshdr->sh_name);
78 if (sname != NULL
79 && (strcmp (sname, ".got") == 0 || strcmp (sname, ".got.plt") == 0))
80 {
81 Elf_Scn *scn = NULL;
82 while ((scn = elf_nextscn (elf, scn)) != NULL)
83 {
84 GElf_Shdr shdr_mem;
85 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
86 if (shdr != NULL)
87 {
88 sname = elf_strptr (elf, shstrndx, shdr->sh_name);
89 if (sname != NULL && strcmp (sname, ".got") == 0)
90 return (sym->st_value >= shdr->sh_addr
91 && sym->st_value < shdr->sh_addr + shdr->sh_size);
92 }
93 }
94 }
95 }
96
97 return false;
98 }
99
100 /* A data mapping symbol is a symbol with "$d" name or "$d.<any...>" name,
101 STT_NOTYPE, STB_LOCAL and st_size of zero. The indicate the stat of a
102 sequence of data items. */
103 bool
aarch64_data_marker_symbol(const GElf_Sym * sym,const char * sname)104 aarch64_data_marker_symbol (const GElf_Sym *sym, const char *sname)
105 {
106 return (sym != NULL && sname != NULL
107 && sym->st_size == 0 && GELF_ST_BIND (sym->st_info) == STB_LOCAL
108 && GELF_ST_TYPE (sym->st_info) == STT_NOTYPE
109 && (strcmp (sname, "$d") == 0 || startswith (sname, "$d.")));
110 }
111
112 const char *
aarch64_dynamic_tag_name(int64_t tag,char * buf,size_t len)113 aarch64_dynamic_tag_name (int64_t tag, char *buf __attribute__ ((unused)),
114 size_t len __attribute__ ((unused)))
115 {
116 switch (tag)
117 {
118 case DT_AARCH64_BTI_PLT:
119 return "AARCH64_BTI_PLT";
120 case DT_AARCH64_PAC_PLT:
121 return "AARCH64_PAC_PLT";
122 case DT_AARCH64_VARIANT_PCS:
123 return "AARCH64_VARIANT_PCS";
124 default:
125 break;
126 }
127 return NULL;
128 }
129
130 bool
aarch64_dynamic_tag_check(int64_t tag)131 aarch64_dynamic_tag_check (int64_t tag)
132 {
133 return (tag == DT_AARCH64_BTI_PLT
134 || tag == DT_AARCH64_PAC_PLT
135 || tag == DT_AARCH64_VARIANT_PCS);
136 }
137