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.  */
41Elf_Type
42ppc_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
57const char *
58ppc_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
72bool
73ppc_dynamic_tag_check (int64_t tag)
74{
75  return tag == DT_PPC_GOT;
76}
77
78
79/* Look for DT_PPC_GOT.  */
80static bool
81find_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.  */
116bool
117ppc_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.  */
153bool
154ppc_bss_plt_p (Elf *elf, GElf_Ehdr *ehdr)
155{
156  GElf_Addr addr;
157  return ! find_dyn_got (elf, ehdr, &addr);
158}
159