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
42const char *
43alpha_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
56bool
57alpha_dynamic_tag_check (int64_t tag)
58{
59  return tag == DT_ALPHA_PLTRO;
60}
61
62/* Check for the simple reloc types.  */
63Elf_Type
64alpha_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.  */
79bool
80alpha_machine_section_flag_check (GElf_Xword sh_flags)
81{
82  return (sh_flags &~ (SHF_ALPHA_GPREL)) == 0;
83}
84
85bool
86alpha_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.  */
131bool
132alpha_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.  */
150bool
151alpha_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