ld/emultempl/ppc32elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2003-2016 Free Software Foundation, Inc.
   3 #
   4 # This file is part of the GNU Binutils.
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19 # MA 02110-1301, USA.
  20 #
  21
  22 # This file is sourced from elf32.em, and defines extra powerpc32-elf
  23 # specific routines.
  24 #
  25 fragment <<EOF
  26
  27 #include "libbfd.h"
  28 #include "elf32-ppc.h"
  29 #include "ldlex.h"
  30 #include "ldlang.h"
  31
  32 #define is_ppc_elf(bfd) \
  33   (bfd_get_flavour (bfd) == bfd_target_elf_flavour \
  34    && elf_object_id (bfd) == PPC32_ELF_DATA)
  35
  36 /* Whether to run tls optimization.  */
  37 static int notlsopt = 0;
  38
  39 /* Choose the correct place for .got.  */
  40 static int old_got = 0;
  41
  42 static bfd_vma pagesize = 0;
  43
  44 static struct ppc_elf_params params = { PLT_UNSET, -1, 0, 0, 0, 0, 0 };
  45
  46 static void
  47 ppc_after_open_output (void)
  48 {
  49   if (params.emit_stub_syms < 0)
  50     params.emit_stub_syms = (link_info.emitrelocations
  51                              || bfd_link_pic (&link_info));
  52   if (pagesize == 0)
  53     pagesize = config.commonpagesize;
  54   params.pagesize_p2 = bfd_log2 (pagesize);
  55   ppc_elf_link_params (&link_info, &params);
  56 }
  57
  58 EOF
  59
  60 # No --secure-plt, --bss-plt, or --sdata-got for vxworks.
  61 if test -z "$VXWORKS_BASE_EM_FILE" ; then
  62   fragment <<EOF
  63 static void
  64 ppc_after_open (void)
  65 {
  66   if (is_ppc_elf (link_info.output_bfd))
  67     {
  68       int new_plt;
  69       int keep_new;
  70       unsigned int num_plt;
  71       unsigned int num_got;
  72       lang_output_section_statement_type *os;
  73       lang_output_section_statement_type *plt_os[2];
  74       lang_output_section_statement_type *got_os[2];
  75
  76       new_plt = ppc_elf_select_plt_layout (link_info.output_bfd, &link_info);
  77       if (new_plt < 0)
  78         einfo ("%X%P: select_plt_layout problem %E\n");
  79
  80       num_got = 0;
  81       num_plt = 0;
  82       for (os = &lang_output_section_statement.head->output_section_statement;
  83            os != NULL;
  84            os = os->next)
  85         {
  86           if (os->constraint == SPECIAL && strcmp (os->name, ".plt") == 0)
  87             {
  88               if (num_plt < 2)
  89                 plt_os[num_plt] = os;
  90               ++num_plt;
  91             }
  92           if (os->constraint == SPECIAL && strcmp (os->name, ".got") == 0)
  93             {
  94               if (num_got < 2)
  95                 got_os[num_got] = os;
  96               ++num_got;
  97             }
  98         }
  99
 100       keep_new = new_plt == 1 ? 0 : -1;
 101       if (num_plt == 2)
 102         {
 103           plt_os[0]->constraint = keep_new;
 104           plt_os[1]->constraint = ~keep_new;
 105         }
 106       if (num_got == 2)
 107         {
 108           if (old_got)
 109             keep_new = -1;
 110           got_os[0]->constraint = keep_new;
 111           got_os[1]->constraint = ~keep_new;
 112         }
 113     }
 114
 115   gld${EMULATION_NAME}_after_open ();
 116 }
 117
 118 EOF
 119 fi
 120 fragment <<EOF
 121 static void
 122 ppc_before_allocation (void)
 123 {
 124   if (is_ppc_elf (link_info.output_bfd))
 125     {
 126       if (ppc_elf_tls_setup (link_info.output_bfd, &link_info)
 127           && !notlsopt)
 128         {
 129           if (!ppc_elf_tls_optimize (link_info.output_bfd, &link_info))
 130             {
 131               einfo ("%X%P: TLS problem %E\n");
 132               return;
 133             }
 134         }
 135     }
 136
 137   gld${EMULATION_NAME}_before_allocation ();
 138
 139   ppc_elf_maybe_strip_sdata_syms (&link_info);
 140
 141   if (RELAXATION_ENABLED)
 142     params.branch_trampolines = 1;
 143
 144   /* Turn on relaxation if executable sections have addresses that
 145      might make branches overflow.  */
 146   else if (!RELAXATION_DISABLED_BY_USER)
 147     {
 148       bfd_vma low = (bfd_vma) -1;
 149       bfd_vma high = 0;
 150       asection *o;
 151
 152       /* Run lang_size_sections (if not already done).  */
 153       if (expld.phase != lang_mark_phase_enum)
 154         {
 155           expld.phase = lang_mark_phase_enum;
 156           expld.dataseg.phase = exp_dataseg_none;
 157           one_lang_size_sections_pass (NULL, FALSE);
 158           lang_reset_memory_regions ();
 159         }
 160
 161       for (o = link_info.output_bfd->sections; o != NULL; o = o->next)
 162         {
 163           if ((o->flags & (SEC_ALLOC | SEC_CODE)) != (SEC_ALLOC | SEC_CODE))
 164             continue;
 165           if (o->rawsize == 0)
 166             continue;
 167           if (low > o->vma)
 168             low = o->vma;
 169           if (high < o->vma + o->rawsize - 1)
 170             high = o->vma + o->rawsize - 1;
 171         }
 172       if (high > low && high - low > (1 << 25) - 1)
 173         params.branch_trampolines = 1;
 174     }
 175
 176   if (params.branch_trampolines
 177       || params.ppc476_workaround
 178       || params.pic_fixup > 0)
 179     ENABLE_RELAXATION;
 180 }
 181
 182 /* Replaces default zero fill padding in executable sections with
 183    "ba 0" instructions.  This works around the ppc476 icache bug if we
 184    have a function pointer tail call near the end of a page, some
 185    small amount of padding, then the function called at the beginning
 186    of the next page.  If the "ba 0" is ever executed we should hit a
 187    segv, so it's almost as good as an illegal instruction (zero).  */
 188
 189 static void
 190 no_zero_padding (lang_statement_union_type *l)
 191 {
 192   if (l->header.type == lang_padding_statement_enum
 193       && l->padding_statement.size != 0
 194       && l->padding_statement.output_section != NULL
 195       && (l->padding_statement.output_section->flags & SEC_CODE) != 0
 196       && l->padding_statement.fill->size == 0)
 197     {
 198       struct _ppc_fill_type
 199       {
 200         size_t size;
 201         unsigned char data[4];
 202       };
 203       static struct _ppc_fill_type fill_be = { 4, {0x48, 0, 0, 2} };
 204       static struct _ppc_fill_type fill_le = { 4, {2, 0, 0, 0x48} };
 205
 206       if (bfd_big_endian (link_info.output_bfd))
 207         l->padding_statement.fill = (struct _fill_type *) &fill_be;
 208       else
 209         l->padding_statement.fill = (struct _fill_type *) &fill_le;
 210     }
 211 }
 212
 213 static void
 214 ppc_finish (void)
 215 {
 216   if (params.ppc476_workaround)
 217     lang_for_each_statement (no_zero_padding);
 218   finish_default ();
 219 }
 220
 221 EOF
 222
 223 if grep -q 'ld_elf32_spu_emulation' ldemul-list.h; then
 224   fragment <<EOF
 225 /* Special handling for embedded SPU executables.  */
 226 extern bfd_boolean embedded_spu_file (lang_input_statement_type *, const char *);
 227 static bfd_boolean gld${EMULATION_NAME}_load_symbols (lang_input_statement_type *);
 228
 229 static bfd_boolean
 230 ppc_recognized_file (lang_input_statement_type *entry)
 231 {
 232   if (embedded_spu_file (entry, "-m32"))
 233     return TRUE;
 234
 235   return gld${EMULATION_NAME}_load_symbols (entry);
 236 }
 237
 238 EOF
 239 LDEMUL_RECOGNIZED_FILE=ppc_recognized_file
 240 fi
 241
 242 # Define some shell vars to insert bits of code into the standard elf
 243 # parse_args and list_options functions.
 244 #
 245 PARSE_AND_LIST_PROLOGUE=${PARSE_AND_LIST_PROLOGUE}'
 246 #define OPTION_NO_TLS_OPT               321
 247 #define OPTION_NO_TLS_GET_ADDR_OPT      (OPTION_NO_TLS_OPT + 1)
 248 #define OPTION_NEW_PLT                  (OPTION_NO_TLS_GET_ADDR_OPT + 1)
 249 #define OPTION_OLD_PLT                  (OPTION_NEW_PLT + 1)
 250 #define OPTION_OLD_GOT                  (OPTION_OLD_PLT + 1)
 251 #define OPTION_STUBSYMS                 (OPTION_OLD_GOT + 1)
 252 #define OPTION_NO_STUBSYMS              (OPTION_STUBSYMS + 1)
 253 #define OPTION_PPC476_WORKAROUND        (OPTION_NO_STUBSYMS + 1)
 254 #define OPTION_NO_PPC476_WORKAROUND     (OPTION_PPC476_WORKAROUND + 1)
 255 #define OPTION_NO_PICFIXUP              (OPTION_NO_PPC476_WORKAROUND + 1)
 256 '
 257
 258 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 259   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 260   { "no-emit-stub-syms", no_argument, NULL, OPTION_NO_STUBSYMS },
 261   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 262   { "no-tls-get-addr-optimize", no_argument, NULL, OPTION_NO_TLS_GET_ADDR_OPT },'
 263 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 264   PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 265   { "secure-plt", no_argument, NULL, OPTION_NEW_PLT },
 266   { "bss-plt", no_argument, NULL, OPTION_OLD_PLT },
 267   { "sdata-got", no_argument, NULL, OPTION_OLD_GOT },'
 268 fi
 269 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 270   { "ppc476-workaround", optional_argument, NULL, OPTION_PPC476_WORKAROUND },
 271   { "no-ppc476-workaround", no_argument, NULL, OPTION_NO_PPC476_WORKAROUND },
 272   { "no-pic-fixup", no_argument, NULL, OPTION_NO_PICFIXUP },
 273 '
 274
 275 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'
 276   fprintf (file, _("\
 277   --emit-stub-syms            Label linker stubs with a symbol.\n\
 278   --no-emit-stub-syms         Don'\''t label linker stubs with a symbol.\n\
 279   --no-tls-optimize           Don'\''t try to optimize TLS accesses.\n\
 280   --no-tls-get-addr-optimize  Don'\''t use a special __tls_get_addr call.\n'
 281 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 282   PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
 283   --secure-plt                Use new-style PLT if possible.\n\
 284   --bss-plt                   Force old-style BSS PLT.\n\
 285   --sdata-got                 Force GOT location just before .sdata.\n'
 286 fi
 287 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
 288   --ppc476-workaround [=pagesize]\n\
 289                               Avoid a cache bug on ppc476.\n\
 290   --no-ppc476-workaround      Disable workaround.\n\
 291   --no-pic-fixup              Don'\''t edit non-pic to pic.\n"
 292                    ));
 293 '
 294
 295 PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
 296     case OPTION_STUBSYMS:
 297       params.emit_stub_syms = 1;
 298       break;
 299
 300     case OPTION_NO_STUBSYMS:
 301       params.emit_stub_syms = 0;
 302       break;
 303
 304     case OPTION_NO_TLS_OPT:
 305       notlsopt = 1;
 306       break;
 307
 308     case OPTION_NO_TLS_GET_ADDR_OPT:
 309       params.no_tls_get_addr_opt = 1;
 310       break;
 311
 312     case OPTION_NEW_PLT:
 313       params.plt_style = PLT_NEW;
 314       break;
 315
 316     case OPTION_OLD_PLT:
 317       params.plt_style = PLT_OLD;
 318       break;
 319
 320     case OPTION_OLD_GOT:
 321       old_got = 1;
 322       break;
 323
 324     case OPTION_TRADITIONAL_FORMAT:
 325       notlsopt = 1;
 326       params.no_tls_get_addr_opt = 1;
 327       return FALSE;
 328
 329     case OPTION_PPC476_WORKAROUND:
 330       params.ppc476_workaround = 1;
 331       if (optarg != NULL)
 332         {
 333           char *end;
 334           pagesize = strtoul (optarg, &end, 0);
 335           if (*end
 336               || (pagesize < 4096 && pagesize != 0)
 337               || pagesize != (pagesize & -pagesize))
 338             einfo (_("%P%F: invalid pagesize `%s'\''\n"), optarg);
 339         }
 340       break;
 341
 342     case OPTION_NO_PPC476_WORKAROUND:
 343       params.ppc476_workaround = 0;
 344       break;
 345
 346     case OPTION_NO_PICFIXUP:
 347       params.pic_fixup = -1;
 348       break;
 349 '
 350
 351 # Put these extra ppc32elf routines in ld_${EMULATION_NAME}_emulation
 352 #
 353 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_after_open_output
 354 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 355   LDEMUL_AFTER_OPEN=ppc_after_open
 356 fi
 357 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 358 LDEMUL_FINISH=ppc_finish