aboutsummaryrefslogtreecommitdiff
path: root/ld/emultempl/ppc32elf.em
blob: 374459c47d7654c79bb4d72e6eb6204c65714066 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
# This shell script emits a C file. -*- C -*-
#   Copyright (C) 2003-2017 Free Software Foundation, Inc.
#
# This file is part of the GNU Binutils.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
# MA 02110-1301, USA.
#

# This file is sourced from elf32.em, and defines extra powerpc32-elf
# specific routines.
#
fragment <<EOF

#include "elf32-ppc.h"
#include "ldlex.h"
#include "ldlang.h"

#define is_ppc_elf(bfd) \
  (bfd_get_flavour (bfd) == bfd_target_elf_flavour \
   && elf_object_id (bfd) == PPC32_ELF_DATA)

/* Whether to run tls optimization.  */
static int notlsopt = 0;

/* Choose the correct place for .got.  */
static int old_got = 0;

static struct ppc_elf_params params = { PLT_UNSET, -1, 0, 0, 0, 0, 0, 0, 0 };

static void
ppc_after_open_output (void)
{
  if (params.emit_stub_syms < 0)
    params.emit_stub_syms = (link_info.emitrelocations
			     || bfd_link_pic (&link_info));
  if (params.pagesize == 0)
    params.pagesize = config.commonpagesize;
  ppc_elf_link_params (&link_info, &params);
}

EOF

# No --secure-plt, --bss-plt, or --sdata-got for vxworks.
if test -z "$VXWORKS_BASE_EM_FILE" ; then
  fragment <<EOF
static void
ppc_after_open (void)
{
  if (is_ppc_elf (link_info.output_bfd))
    {
      int new_plt;
      int keep_new;
      unsigned int num_plt;
      unsigned int num_got;
      lang_output_section_statement_type *os;
      lang_output_section_statement_type *plt_os[2];
      lang_output_section_statement_type *got_os[2];

      new_plt = ppc_elf_select_plt_layout (link_info.output_bfd, &link_info);
      if (new_plt < 0)
	einfo (_("%X%P: select_plt_layout problem %E\n"));

      num_got = 0;
      num_plt = 0;
      for (os = &lang_output_section_statement.head->output_section_statement;
	   os != NULL;
	   os = os->next)
	{
	  if (os->constraint == SPECIAL && strcmp (os->name, ".plt") == 0)
	    {
	      if (num_plt < 2)
		plt_os[num_plt] = os;
	      ++num_plt;
	    }
	  if (os->constraint == SPECIAL && strcmp (os->name, ".got") == 0)
	    {
	      if (num_got < 2)
		got_os[num_got] = os;
	      ++num_got;
	    }
	}

      keep_new = new_plt == 1 ? 0 : -1;
      if (num_plt == 2)
	{
	  plt_os[0]->constraint = keep_new;
	  plt_os[1]->constraint = ~keep_new;
	}
      if (num_got == 2)
	{
	  if (old_got)
	    keep_new = -1;
	  got_os[0]->constraint = keep_new;
	  got_os[1]->constraint = ~keep_new;
	}
    }

  gld${EMULATION_NAME}_after_open ();
}

EOF
fi
fragment <<EOF
static void
ppc_before_allocation (void)
{
  if (is_ppc_elf (link_info.output_bfd))
    {
      if (ppc_elf_tls_setup (link_info.output_bfd, &link_info)
	  && !notlsopt)
	{
	  if (!ppc_elf_tls_optimize (link_info.output_bfd, &link_info))
	    {
	      einfo (_("%X%P: TLS problem %E\n"));
	      return;
	    }
	}
    }

  gld${EMULATION_NAME}_before_allocation ();

  ppc_elf_maybe_strip_sdata_syms (&link_info);

  if (RELAXATION_ENABLED)
    params.branch_trampolines = 1;

  /* Turn on relaxation if executable sections have addresses that
     might make branches overflow.  */
  else if (!RELAXATION_DISABLED_BY_USER)
    {
      bfd_vma low = (bfd_vma) -1;
      bfd_vma high = 0;
      asection *o;

      /* Run lang_size_sections (if not already done).  */
      if (expld.phase != lang_mark_phase_enum)
	{
	  expld.phase = lang_mark_phase_enum;
	  expld.dataseg.phase = exp_dataseg_none;
	  one_lang_size_sections_pass (NULL, FALSE);
	  lang_reset_memory_regions ();
	}

      for (o = link_info.output_bfd->sections; o != NULL; o = o->next)
	{
	  if ((o->flags & (SEC_ALLOC | SEC_CODE)) != (SEC_ALLOC | SEC_CODE))
	    continue;
	  if (o->rawsize == 0)
	    continue;
	  if (low > o->vma)
	    low = o->vma;
	  if (high < o->vma + o->rawsize - 1)
	    high = o->vma + o->rawsize - 1;
	}
      if (high > low && high - low > (1 << 25) - 1)
	params.branch_trampolines = 1;
    }

  if (params.branch_trampolines
      || params.ppc476_workaround
      || params.pic_fixup > 0)
    ENABLE_RELAXATION;
}

/* Replaces default zero fill padding in executable sections with
   "ba 0" instructions.  This works around the ppc476 icache bug if we
   have a function pointer tail call near the end of a page, some
   small amount of padding, then the function called at the beginning
   of the next page.  If the "ba 0" is ever executed we should hit a
   segv, so it's almost as good as an illegal instruction (zero).  */

static void
no_zero_padding (lang_statement_union_type *l)
{
  if (l->header.type == lang_padding_statement_enum
      && l->padding_statement.size != 0
      && l->padding_statement.output_section != NULL
      && (l->padding_statement.output_section->flags & SEC_CODE) != 0
      && l->padding_statement.fill->size == 0)
    {
      struct _ppc_fill_type
      {
	size_t size;
	unsigned char data[4];
      };
      static struct _ppc_fill_type fill_be = { 4, {0x48, 0, 0, 2} };
      static struct _ppc_fill_type fill_le = { 4, {2, 0, 0, 0x48} };

      if (bfd_big_endian (link_info.output_bfd))
	l->padding_statement.fill = (struct _fill_type *) &fill_be;
      else
	l->padding_statement.fill = (struct _fill_type *) &fill_le;
    }
}

static void
ppc_finish (void)
{
  if (params.ppc476_workaround)
    lang_for_each_statement (no_zero_padding);
  finish_default ();
}

EOF

if grep -q 'ld_elf32_spu_emulation' ldemul-list.h; then
  fragment <<EOF
/* Special handling for embedded SPU executables.  */
extern bfd_boolean embedded_spu_file (lang_input_statement_type *, const char *);
static bfd_boolean gld${EMULATION_NAME}_load_symbols (lang_input_statement_type *);

static bfd_boolean
ppc_recognized_file (lang_input_statement_type *entry)
{
  if (embedded_spu_file (entry, "-m32"))
    return TRUE;

  return gld${EMULATION_NAME}_load_symbols (entry);
}

EOF
LDEMUL_RECOGNIZED_FILE=ppc_recognized_file
fi

# Define some shell vars to insert bits of code into the standard elf
# parse_args and list_options functions.
#
PARSE_AND_LIST_PROLOGUE=${PARSE_AND_LIST_PROLOGUE}'
#define OPTION_NO_TLS_OPT		321
#define OPTION_NO_TLS_GET_ADDR_OPT	(OPTION_NO_TLS_OPT + 1)
#define OPTION_NEW_PLT			(OPTION_NO_TLS_GET_ADDR_OPT + 1)
#define OPTION_OLD_PLT			(OPTION_NEW_PLT + 1)
#define OPTION_OLD_GOT			(OPTION_OLD_PLT + 1)
#define OPTION_STUBSYMS			(OPTION_OLD_GOT + 1)
#define OPTION_NO_STUBSYMS		(OPTION_STUBSYMS + 1)
#define OPTION_PPC476_WORKAROUND	(OPTION_NO_STUBSYMS + 1)
#define OPTION_NO_PPC476_WORKAROUND	(OPTION_PPC476_WORKAROUND + 1)
#define OPTION_NO_PICFIXUP		(OPTION_NO_PPC476_WORKAROUND + 1)
#define OPTION_VLE_RELOC_FIXUP		(OPTION_NO_PICFIXUP + 1)
'

PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
  { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
  { "no-emit-stub-syms", no_argument, NULL, OPTION_NO_STUBSYMS },
  { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
  { "no-tls-get-addr-optimize", no_argument, NULL, OPTION_NO_TLS_GET_ADDR_OPT },'
if test -z "$VXWORKS_BASE_EM_FILE" ; then
  PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
  { "secure-plt", no_argument, NULL, OPTION_NEW_PLT },
  { "bss-plt", no_argument, NULL, OPTION_OLD_PLT },
  { "sdata-got", no_argument, NULL, OPTION_OLD_GOT },'
fi
PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
  { "ppc476-workaround", optional_argument, NULL, OPTION_PPC476_WORKAROUND },
  { "no-ppc476-workaround", no_argument, NULL, OPTION_NO_PPC476_WORKAROUND },
  { "no-pic-fixup", no_argument, NULL, OPTION_NO_PICFIXUP },
  { "vle-reloc-fixup", no_argument, NULL, OPTION_VLE_RELOC_FIXUP },
'

PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'
  fprintf (file, _("\
  --emit-stub-syms            Label linker stubs with a symbol.\n\
  --no-emit-stub-syms         Don'\''t label linker stubs with a symbol.\n\
  --no-tls-optimize           Don'\''t try to optimize TLS accesses.\n\
  --no-tls-get-addr-optimize  Don'\''t use a special __tls_get_addr call.\n'
if test -z "$VXWORKS_BASE_EM_FILE" ; then
  PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
  --secure-plt                Use new-style PLT if possible.\n\
  --bss-plt                   Force old-style BSS PLT.\n\
  --sdata-got                 Force GOT location just before .sdata.\n'
fi
PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
  --ppc476-workaround [=pagesize]\n\
                              Avoid a cache bug on ppc476.\n\
  --no-ppc476-workaround      Disable workaround.\n\
  --no-pic-fixup              Don'\''t edit non-pic to pic.\n\
  --vle-reloc-fixup           Correct old object file 16A/16D relocation.\n"
		   ));
'

PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
    case OPTION_STUBSYMS:
      params.emit_stub_syms = 1;
      break;

    case OPTION_NO_STUBSYMS:
      params.emit_stub_syms = 0;
      break;

    case OPTION_NO_TLS_OPT:
      notlsopt = 1;
      break;

    case OPTION_NO_TLS_GET_ADDR_OPT:
      params.no_tls_get_addr_opt = 1;
      break;

    case OPTION_NEW_PLT:
      params.plt_style = PLT_NEW;
      break;

    case OPTION_OLD_PLT:
      params.plt_style = PLT_OLD;
      break;

    case OPTION_OLD_GOT:
      old_got = 1;
      break;

    case OPTION_TRADITIONAL_FORMAT:
      notlsopt = 1;
      params.no_tls_get_addr_opt = 1;
      return FALSE;

    case OPTION_PPC476_WORKAROUND:
      params.ppc476_workaround = 1;
      if (optarg != NULL)
	{
	  char *end;
	  params.pagesize = strtoul (optarg, &end, 0);
	  if (*end
	      || (params.pagesize < 4096 && params.pagesize != 0)
	      || params.pagesize != (params.pagesize & -params.pagesize))
	    einfo (_("%P%F: invalid pagesize `%s'\''\n"), optarg);
	}
      break;

    case OPTION_NO_PPC476_WORKAROUND:
      params.ppc476_workaround = 0;
      break;

    case OPTION_NO_PICFIXUP:
      params.pic_fixup = -1;
      break;

    case OPTION_VLE_RELOC_FIXUP:
      params.vle_reloc_fixup = 1;
      break;
'

# Put these extra ppc32elf routines in ld_${EMULATION_NAME}_emulation
#
LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_after_open_output
if test -z "$VXWORKS_BASE_EM_FILE" ; then
  LDEMUL_AFTER_OPEN=ppc_after_open
fi
LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
LDEMUL_FINISH=ppc_finish