1 /* Alpha specific symbolic name handling.
2 Copyright (C) 2002-2011 Red Hat, Inc.
3 This file is part of elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 2002.
5
6 This file is free software; you can redistribute it and/or modify
7 it under the terms of either
8
9 * the GNU Lesser General Public License as published by the Free
10 Software Foundation; either version 3 of the License, or (at
11 your option) any later version
12
13 or
14
15 * the GNU General Public License as published by the Free
16 Software Foundation; either version 2 of the License, or (at
17 your option) any later version
18
19 or both in parallel, as here.
20
21 elfutils is distributed in the hope that it will be useful, but
22 WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 General Public License for more details.
25
26 You should have received copies of the GNU General Public License and
27 the GNU Lesser General Public License along with this program. If
28 not, see <http://www.gnu.org/licenses/>. */
29
30 #ifdef HAVE_CONFIG_H
31 # include <config.h>
32 #endif
33
34 #include <elf.h>
35 #include <stddef.h>
36 #include <string.h>
37
38 #define BACKEND alpha_
39 #include "libebl_CPU.h"
40
41
42 const char *
alpha_dynamic_tag_name(int64_t tag,char * buf,size_t len)43 alpha_dynamic_tag_name (int64_t tag, char *buf __attribute__ ((unused)),
44 size_t len __attribute__ ((unused)))
45 {
46 switch (tag)
47 {
48 case DT_ALPHA_PLTRO:
49 return "ALPHA_PLTRO";
50 default:
51 break;
52 }
53 return NULL;
54 }
55
56 bool
alpha_dynamic_tag_check(int64_t tag)57 alpha_dynamic_tag_check (int64_t tag)
58 {
59 return tag == DT_ALPHA_PLTRO;
60 }
61
62 /* Check for the simple reloc types. */
63 Elf_Type
alpha_reloc_simple_type(Ebl * ebl,int type)64 alpha_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type)
65 {
66 switch (type)
67 {
68 case R_ALPHA_REFLONG:
69 return ELF_T_WORD;
70 case R_ALPHA_REFQUAD:
71 return ELF_T_XWORD;
72 default:
73 return ELF_T_NUM;
74 }
75 }
76
77
78 /* Check whether SHF_MASKPROC flags are valid. */
79 bool
alpha_machine_section_flag_check(GElf_Xword sh_flags)80 alpha_machine_section_flag_check (GElf_Xword sh_flags)
81 {
82 return (sh_flags &~ (SHF_ALPHA_GPREL)) == 0;
83 }
84
85 bool
alpha_check_special_section(Ebl * ebl,int ndx,const GElf_Shdr * shdr,const char * sname)86 alpha_check_special_section (Ebl *ebl,
87 int ndx __attribute__ ((unused)),
88 const GElf_Shdr *shdr,
89 const char *sname __attribute__ ((unused)))
90 {
91 if ((shdr->sh_flags
92 & (SHF_WRITE | SHF_EXECINSTR)) == (SHF_WRITE | SHF_EXECINSTR)
93 && shdr->sh_addr != 0)
94 {
95 /* This is ordinarily flagged, but is valid for an old-style PLT.
96
97 Look for the SHT_DYNAMIC section and the DT_PLTGOT tag in it.
98 Its d_ptr should match the .plt section's sh_addr. */
99
100 Elf_Scn *scn = NULL;
101 while ((scn = elf_nextscn (ebl->elf, scn)) != NULL)
102 {
103 GElf_Shdr scn_shdr;
104 if (likely (gelf_getshdr (scn, &scn_shdr) != NULL)
105 && scn_shdr.sh_type == SHT_DYNAMIC
106 && scn_shdr.sh_entsize != 0)
107 {
108 GElf_Addr pltgot = 0;
109 Elf_Data *data = elf_getdata (scn, NULL);
110 if (data != NULL)
111 for (size_t i = 0; i < data->d_size / scn_shdr.sh_entsize; ++i)
112 {
113 GElf_Dyn dyn;
114 if (unlikely (gelf_getdyn (data, i, &dyn) == NULL))
115 break;
116 if (dyn.d_tag == DT_PLTGOT)
117 pltgot = dyn.d_un.d_ptr;
118 else if (dyn.d_tag == DT_ALPHA_PLTRO && dyn.d_un.d_val != 0)
119 return false; /* This PLT should not be writable. */
120 }
121 return pltgot == shdr->sh_addr;
122 }
123 }
124 }
125
126 return false;
127 }
128
129 /* Check whether given symbol's st_value and st_size are OK despite failing
130 normal checks. */
131 bool
alpha_check_special_symbol(Elf * elf,GElf_Ehdr * ehdr,const GElf_Sym * sym,const char * name,const GElf_Shdr * destshdr)132 alpha_check_special_symbol (Elf *elf __attribute__ ((unused)),
133 GElf_Ehdr *ehdr __attribute__ ((unused)),
134 const GElf_Sym *sym __attribute__ ((unused)),
135 const char *name,
136 const GElf_Shdr *destshdr __attribute__ ((unused)))
137 {
138 if (name == NULL)
139 return false;
140
141 if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
142 /* On Alpha any place in the section is valid. */
143 return true;
144
145 return false;
146 }
147
148 /* Check whether only valid bits are set on the st_other symbol flag.
149 Standard ST_VISIBILITY have already been masked off. */
150 bool
alpha_check_st_other_bits(unsigned char st_other)151 alpha_check_st_other_bits (unsigned char st_other)
152 {
153 return ((((st_other & STO_ALPHA_STD_GPLOAD) == STO_ALPHA_NOPV)
154 || ((st_other & STO_ALPHA_STD_GPLOAD) == STO_ALPHA_STD_GPLOAD))
155 && (st_other &~ STO_ALPHA_STD_GPLOAD) == 0);
156 }
157