1 /* PPC specific symbolic name handling.
2 Copyright (C) 2004, 2005, 2007 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 2004.
5
6 Red Hat elfutils is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by the
8 Free Software Foundation; version 2 of the License.
9
10 Red Hat elfutils is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with Red Hat elfutils; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19 Red Hat elfutils is an included package of the Open Invention Network.
20 An included package of the Open Invention Network is a package for which
21 Open Invention Network licensees cross-license their patents. No patent
22 license is granted, either expressly or impliedly, by designation as an
23 included package. Should you wish to participate in the Open Invention
24 Network licensing program, please visit www.openinventionnetwork.com
25 <http://www.openinventionnetwork.com>. */
26
27 #ifdef HAVE_CONFIG_H
28 # include <config.h>
29 #endif
30
31 #include <assert.h>
32 #include <elf.h>
33 #include <stddef.h>
34 #include <string.h>
35
36 #define BACKEND ppc_
37 #include "libebl_CPU.h"
38
39
40 /* Check for the simple reloc types. */
41 Elf_Type
ppc_reloc_simple_type(Ebl * ebl,int type)42 ppc_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type)
43 {
44 switch (type)
45 {
46 case R_PPC_ADDR32:
47 case R_PPC_UADDR32:
48 return ELF_T_WORD;
49 case R_PPC_UADDR16:
50 return ELF_T_HALF;
51 default:
52 return ELF_T_NUM;
53 }
54 }
55
56
57 const char *
ppc_dynamic_tag_name(int64_t tag,char * buf,size_t len)58 ppc_dynamic_tag_name (int64_t tag, char *buf __attribute__ ((unused)),
59 size_t len __attribute__ ((unused)))
60 {
61 switch (tag)
62 {
63 case DT_PPC_GOT:
64 return "PPC_GOT";
65 default:
66 break;
67 }
68 return NULL;
69 }
70
71
72 bool
ppc_dynamic_tag_check(int64_t tag)73 ppc_dynamic_tag_check (int64_t tag)
74 {
75 return tag == DT_PPC_GOT;
76 }
77
78
79 /* Look for DT_PPC_GOT. */
80 static bool
find_dyn_got(Elf * elf,GElf_Ehdr * ehdr,GElf_Addr * addr)81 find_dyn_got (Elf *elf, GElf_Ehdr *ehdr, GElf_Addr *addr)
82 {
83 for (int i = 0; i < ehdr->e_phnum; ++i)
84 {
85 GElf_Phdr phdr_mem;
86 GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
87 if (phdr == NULL || phdr->p_type != PT_DYNAMIC)
88 continue;
89
90 Elf_Scn *scn = gelf_offscn (elf, phdr->p_offset);
91 GElf_Shdr shdr_mem;
92 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
93 Elf_Data *data = elf_getdata (scn, NULL);
94 if (shdr != NULL && shdr->sh_type == SHT_DYNAMIC && data != NULL)
95 for (unsigned int j = 0; j < shdr->sh_size / shdr->sh_entsize; ++j)
96 {
97 GElf_Dyn dyn_mem;
98 GElf_Dyn *dyn = gelf_getdyn (data, j, &dyn_mem);
99 if (dyn != NULL && dyn->d_tag == DT_PPC_GOT)
100 {
101 *addr = dyn->d_un.d_ptr;
102 return true;
103 }
104 }
105
106 /* There is only one PT_DYNAMIC entry. */
107 break;
108 }
109
110 return false;
111 }
112
113
114 /* Check whether given symbol's st_value and st_size are OK despite failing
115 normal checks. */
116 bool
ppc_check_special_symbol(Elf * elf,GElf_Ehdr * ehdr,const GElf_Sym * sym,const char * name,const GElf_Shdr * destshdr)117 ppc_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
118 const char *name, const GElf_Shdr *destshdr)
119 {
120 if (name == NULL)
121 return false;
122
123 if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
124 {
125 /* In -msecure-plt mode, DT_PPC_GOT is present and must match. */
126 GElf_Addr gotaddr;
127 if (find_dyn_got (elf, ehdr, &gotaddr))
128 return sym->st_value == gotaddr;
129
130 /* In -mbss-plt mode, any place in the section is valid. */
131 return true;
132 }
133
134 const char *sname = elf_strptr (elf, ehdr->e_shstrndx, destshdr->sh_name);
135 if (sname == NULL)
136 return false;
137
138 if (strcmp (name, "_SDA_BASE_") == 0)
139 return (strcmp (sname, ".sdata") == 0
140 && sym->st_value == destshdr->sh_addr + 0x8000
141 && sym->st_size == 0);
142
143 if (strcmp (name, "_SDA2_BASE_") == 0)
144 return (strcmp (sname, ".sdata2") == 0
145 && sym->st_value == destshdr->sh_addr + 0x8000
146 && sym->st_size == 0);
147
148 return false;
149 }
150
151
152 /* Check if backend uses a bss PLT in this file. */
153 bool
ppc_bss_plt_p(Elf * elf,GElf_Ehdr * ehdr)154 ppc_bss_plt_p (Elf *elf, GElf_Ehdr *ehdr)
155 {
156 GElf_Addr addr;
157 return ! find_dyn_got (elf, ehdr, &addr);
158 }
159