Line data Source code
1 : /* PPC specific symbolic name handling.
2 : Copyright (C) 2004, 2005, 2007, 2014, 2015 Red Hat, Inc.
3 : This file is part of elfutils.
4 : Written by Ulrich Drepper <drepper@redhat.com>, 2004.
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 <assert.h>
35 : #include <elf.h>
36 : #include <stddef.h>
37 : #include <string.h>
38 :
39 : #define BACKEND ppc_
40 : #include "libebl_CPU.h"
41 :
42 :
43 : /* Check for the simple reloc types. */
44 : Elf_Type
45 0 : ppc_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type,
46 : int *addsub __attribute__ ((unused)))
47 : {
48 0 : switch (type)
49 : {
50 : case R_PPC_ADDR32:
51 : case R_PPC_UADDR32:
52 : return ELF_T_WORD;
53 0 : case R_PPC_UADDR16:
54 0 : return ELF_T_HALF;
55 0 : default:
56 0 : return ELF_T_NUM;
57 : }
58 : }
59 :
60 :
61 : /* Check whether machine flags are valid. */
62 : bool
63 21 : ppc_machine_flag_check (GElf_Word flags)
64 : {
65 21 : return ((flags &~ (EF_PPC_EMB
66 : | EF_PPC_RELOCATABLE
67 21 : | EF_PPC_RELOCATABLE_LIB)) == 0);
68 : }
69 :
70 :
71 : const char *
72 0 : ppc_dynamic_tag_name (int64_t tag, char *buf __attribute__ ((unused)),
73 : size_t len __attribute__ ((unused)))
74 : {
75 0 : switch (tag)
76 : {
77 : case DT_PPC_GOT:
78 : return "PPC_GOT";
79 0 : case DT_PPC_OPT:
80 0 : return "PPC_OPT";
81 : default:
82 0 : break;
83 : }
84 0 : return NULL;
85 : }
86 :
87 :
88 : bool
89 180 : ppc_dynamic_tag_check (int64_t tag)
90 : {
91 180 : return (tag == DT_PPC_GOT
92 180 : || tag == DT_PPC_OPT);
93 : }
94 :
95 :
96 : /* Look for DT_PPC_GOT. */
97 : static bool
98 18 : find_dyn_got (Elf *elf, GElf_Addr *addr)
99 : {
100 18 : size_t phnum;
101 18 : if (elf_getphdrnum (elf, &phnum) != 0)
102 : return false;
103 :
104 90 : for (size_t i = 0; i < phnum; ++i)
105 : {
106 90 : GElf_Phdr phdr_mem;
107 90 : GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
108 90 : if (phdr == NULL || phdr->p_type != PT_DYNAMIC)
109 72 : continue;
110 :
111 18 : Elf_Scn *scn = gelf_offscn (elf, phdr->p_offset);
112 18 : GElf_Shdr shdr_mem;
113 18 : GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
114 18 : Elf_Data *data = elf_getdata (scn, NULL);
115 18 : if (shdr != NULL && shdr->sh_type == SHT_DYNAMIC && data != NULL
116 18 : && shdr->sh_entsize != 0)
117 324 : for (unsigned int j = 0; j < shdr->sh_size / shdr->sh_entsize; ++j)
118 : {
119 324 : GElf_Dyn dyn_mem;
120 324 : GElf_Dyn *dyn = gelf_getdyn (data, j, &dyn_mem);
121 324 : if (dyn != NULL && dyn->d_tag == DT_PPC_GOT)
122 : {
123 18 : *addr = dyn->d_un.d_ptr;
124 18 : return true;
125 : }
126 : }
127 :
128 : /* There is only one PT_DYNAMIC entry. */
129 0 : break;
130 : }
131 :
132 : return false;
133 : }
134 :
135 :
136 : /* Check whether given symbol's st_value and st_size are OK despite failing
137 : normal checks. */
138 : bool
139 600 : ppc_check_special_symbol (Elf *elf, const GElf_Sym *sym,
140 : const char *name, const GElf_Shdr *destshdr)
141 : {
142 600 : if (name == NULL)
143 : return false;
144 :
145 600 : if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
146 : {
147 : /* In -msecure-plt mode, DT_PPC_GOT is present and must match. */
148 12 : GElf_Addr gotaddr;
149 12 : if (find_dyn_got (elf, &gotaddr))
150 12 : return sym->st_value == gotaddr;
151 :
152 : /* In -mbss-plt mode, any place in the section is valid. */
153 : return true;
154 : }
155 :
156 588 : size_t shstrndx;
157 588 : if (elf_getshdrstrndx (elf, &shstrndx) != 0)
158 : return false;
159 588 : const char *sname = elf_strptr (elf, shstrndx, destshdr->sh_name);
160 588 : if (sname == NULL)
161 : return false;
162 :
163 : /* Small data area. Normally points to .sdata, in which case we
164 : check it is at an offset of 0x8000. It might however fall in the
165 : .data section, in which case we cannot check the offset. The
166 : size always should be zero. */
167 588 : if (strcmp (name, "_SDA_BASE_") == 0)
168 6 : return (((strcmp (sname, ".sdata") == 0
169 6 : && sym->st_value == destshdr->sh_addr + 0x8000)
170 0 : || strcmp (sname, ".data") == 0)
171 12 : && sym->st_size == 0);
172 :
173 582 : if (strcmp (name, "_SDA2_BASE_") == 0)
174 0 : return (strcmp (sname, ".sdata2") == 0
175 0 : && sym->st_value == destshdr->sh_addr + 0x8000
176 0 : && sym->st_size == 0);
177 :
178 : return false;
179 : }
180 :
181 :
182 : /* Check if backend uses a bss PLT in this file. */
183 : bool
184 6 : ppc_bss_plt_p (Elf *elf)
185 : {
186 6 : GElf_Addr addr;
187 6 : return ! find_dyn_got (elf, &addr);
188 : }
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