ld/emultempl/ppc32elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2003-2014 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 };
  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 || link_info.shared;
  51   if (pagesize == 0)
  52     pagesize = config.commonpagesize;
  53   params.pagesize_p2 = bfd_log2 (pagesize);
  54   ppc_elf_link_params (&link_info, &params);
  55 }
  56
  57 EOF
  58
  59 # No --secure-plt, --bss-plt, or --sdata-got for vxworks.
  60 if test -z "$VXWORKS_BASE_EM_FILE" ; then
  61   fragment <<EOF
  62 static void
  63 ppc_after_open (void)
  64 {
  65   if (is_ppc_elf (link_info.output_bfd))
  66     {
  67       int new_plt;
  68       int keep_new;
  69       unsigned int num_plt;
  70       unsigned int num_got;
  71       lang_output_section_statement_type *os;
  72       lang_output_section_statement_type *plt_os[2];
  73       lang_output_section_statement_type *got_os[2];
  74
  75       new_plt = ppc_elf_select_plt_layout (link_info.output_bfd, &link_info);
  76       if (new_plt < 0)
  77         einfo ("%X%P: select_plt_layout problem %E\n");
  78
  79       num_got = 0;
  80       num_plt = 0;
  81       for (os = &lang_output_section_statement.head->output_section_statement;
  82            os != NULL;
  83            os = os->next)
  84         {
  85           if (os->constraint == SPECIAL && strcmp (os->name, ".plt") == 0)
  86             {
  87               if (num_plt < 2)
  88                 plt_os[num_plt] = os;
  89               ++num_plt;
  90             }
  91           if (os->constraint == SPECIAL && strcmp (os->name, ".got") == 0)
  92             {
  93               if (num_got < 2)
  94                 got_os[num_got] = os;
  95               ++num_got;
  96             }
  97         }
  98
  99       keep_new = new_plt == 1 ? 0 : -1;
 100       if (num_plt == 2)
 101         {
 102           plt_os[0]->constraint = keep_new;
 103           plt_os[1]->constraint = ~keep_new;
 104         }
 105       if (num_got == 2)
 106         {
 107           if (old_got)
 108             keep_new = -1;
 109           got_os[0]->constraint = keep_new;
 110           got_os[1]->constraint = ~keep_new;
 111         }
 112     }
 113
 114   gld${EMULATION_NAME}_after_open ();
 115 }
 116
 117 EOF
 118 fi
 119 fragment <<EOF
 120 static void
 121 ppc_before_allocation (void)
 122 {
 123   if (is_ppc_elf (link_info.output_bfd))
 124     {
 125       if (ppc_elf_tls_setup (link_info.output_bfd, &link_info)
 126           && !notlsopt)
 127         {
 128           if (!ppc_elf_tls_optimize (link_info.output_bfd, &link_info))
 129             {
 130               einfo ("%X%P: TLS problem %E\n");
 131               return;
 132             }
 133         }
 134     }
 135
 136   gld${EMULATION_NAME}_before_allocation ();
 137
 138   ppc_elf_maybe_strip_sdata_syms (&link_info);
 139
 140   if (RELAXATION_ENABLED)
 141     params.branch_trampolines = 1;
 142
 143   /* Turn on relaxation if executable sections have addresses that
 144      might make branches overflow.  */
 145   else if (!RELAXATION_DISABLED_BY_USER)
 146     {
 147       bfd_vma low = (bfd_vma) -1;
 148       bfd_vma high = 0;
 149       asection *o;
 150
 151       /* Run lang_size_sections (if not already done).  */
 152       if (expld.phase != lang_mark_phase_enum)
 153         {
 154           expld.phase = lang_mark_phase_enum;
 155           expld.dataseg.phase = exp_dataseg_none;
 156           one_lang_size_sections_pass (NULL, FALSE);
 157           lang_reset_memory_regions ();
 158         }
 159
 160       for (o = link_info.output_bfd->sections; o != NULL; o = o->next)
 161         {
 162           if ((o->flags & (SEC_ALLOC | SEC_CODE)) != (SEC_ALLOC | SEC_CODE))
 163             continue;
 164           if (o->rawsize == 0)
 165             continue;
 166           if (low > o->vma)
 167             low = o->vma;
 168           if (high < o->vma + o->rawsize - 1)
 169             high = o->vma + o->rawsize - 1;
 170         }
 171       if (high > low && high - low > (1 << 25) - 1)
 172         params.branch_trampolines = 1;
 173     }
 174
 175   if (params.ppc476_workaround || params.branch_trampolines)
 176     ENABLE_RELAXATION;
 177 }
 178
 179 /* Replaces default zero fill padding in executable sections with
 180    "ba 0" instructions.  This works around the ppc476 icache bug if we
 181    have a function pointer tail call near the end of a page, some
 182    small amount of padding, then the function called at the beginning
 183    of the next page.  If the "ba 0" is ever executed we should hit a
 184    segv, so it's almost as good as an illegal instruction (zero).  */
 185
 186 static void
 187 no_zero_padding (lang_statement_union_type *l)
 188 {
 189   if (l->header.type == lang_padding_statement_enum
 190       && l->padding_statement.size != 0
 191       && l->padding_statement.output_section != NULL
 192       && (l->padding_statement.output_section->flags & SEC_CODE) != 0
 193       && l->padding_statement.fill->size == 0)
 194     {
 195       struct _ppc_fill_type
 196       {
 197         size_t size;
 198         unsigned char data[4];
 199       };
 200       static struct _ppc_fill_type fill_be = { 4, {0x48, 0, 0, 2} };
 201       static struct _ppc_fill_type fill_le = { 4, {2, 0, 0, 0x48} };
 202
 203       if (bfd_big_endian (link_info.output_bfd))
 204         l->padding_statement.fill = (struct _fill_type *) &fill_be;
 205       else
 206         l->padding_statement.fill = (struct _fill_type *) &fill_le;
 207     }
 208 }
 209
 210 static void
 211 ppc_finish (void)
 212 {
 213   if (params.ppc476_workaround)
 214     lang_for_each_statement (no_zero_padding);
 215   finish_default ();
 216 }
 217
 218 EOF
 219
 220 if grep -q 'ld_elf32_spu_emulation' ldemul-list.h; then
 221   fragment <<EOF
 222 /* Special handling for embedded SPU executables.  */
 223 extern bfd_boolean embedded_spu_file (lang_input_statement_type *, const char *);
 224 static bfd_boolean gld${EMULATION_NAME}_load_symbols (lang_input_statement_type *);
 225
 226 static bfd_boolean
 227 ppc_recognized_file (lang_input_statement_type *entry)
 228 {
 229   if (embedded_spu_file (entry, "-m32"))
 230     return TRUE;
 231
 232   return gld${EMULATION_NAME}_load_symbols (entry);
 233 }
 234
 235 EOF
 236 LDEMUL_RECOGNIZED_FILE=ppc_recognized_file
 237 fi
 238
 239 # Define some shell vars to insert bits of code into the standard elf
 240 # parse_args and list_options functions.
 241 #
 242 PARSE_AND_LIST_PROLOGUE=${PARSE_AND_LIST_PROLOGUE}'
 243 #define OPTION_NO_TLS_OPT               321
 244 #define OPTION_NO_TLS_GET_ADDR_OPT      (OPTION_NO_TLS_OPT + 1)
 245 #define OPTION_NEW_PLT                  (OPTION_NO_TLS_GET_ADDR_OPT + 1)
 246 #define OPTION_OLD_PLT                  (OPTION_NEW_PLT + 1)
 247 #define OPTION_OLD_GOT                  (OPTION_OLD_PLT + 1)
 248 #define OPTION_STUBSYMS                 (OPTION_OLD_GOT + 1)
 249 #define OPTION_NO_STUBSYMS              (OPTION_STUBSYMS + 1)
 250 #define OPTION_PPC476_WORKAROUND        (OPTION_NO_STUBSYMS + 1)
 251 #define OPTION_NO_PPC476_WORKAROUND     (OPTION_PPC476_WORKAROUND + 1)
 252 '
 253
 254 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 255   { "emit-stub-syms", no_argument, NULL, OPTION_STUBSYMS },
 256   { "no-emit-stub-syms", no_argument, NULL, OPTION_NO_STUBSYMS },
 257   { "no-tls-optimize", no_argument, NULL, OPTION_NO_TLS_OPT },
 258   { "no-tls-get-addr-optimize", no_argument, NULL, OPTION_NO_TLS_GET_ADDR_OPT },'
 259 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 260   PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 261   { "secure-plt", no_argument, NULL, OPTION_NEW_PLT },
 262   { "bss-plt", no_argument, NULL, OPTION_OLD_PLT },
 263   { "sdata-got", no_argument, NULL, OPTION_OLD_GOT },'
 264 fi
 265 PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
 266   { "ppc476-workaround", optional_argument, NULL, OPTION_PPC476_WORKAROUND },
 267   { "no-ppc476-workaround", no_argument, NULL, OPTION_NO_PPC476_WORKAROUND },
 268 '
 269
 270 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'
 271   fprintf (file, _("\
 272   --emit-stub-syms            Label linker stubs with a symbol.\n\
 273   --no-emit-stub-syms         Don'\''t label linker stubs with a symbol.\n\
 274   --no-tls-optimize           Don'\''t try to optimize TLS accesses.\n\
 275   --no-tls-get-addr-optimize  Don'\''t use a special __tls_get_addr call.\n'
 276 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 277   PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
 278   --secure-plt                Use new-style PLT if possible.\n\
 279   --bss-plt                   Force old-style BSS PLT.\n\
 280   --sdata-got                 Force GOT location just before .sdata.\n'
 281 fi
 282 PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'\
 283   --ppc476-workaround [=pagesize]\n\
 284                               Avoid a cache bug on ppc476.\n\
 285   --no-ppc476-workaround      Disable workaround.\n"
 286                    ));
 287 '
 288
 289 PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
 290     case OPTION_STUBSYMS:
 291       params.emit_stub_syms = 1;
 292       break;
 293
 294     case OPTION_NO_STUBSYMS:
 295       params.emit_stub_syms = 0;
 296       break;
 297
 298     case OPTION_NO_TLS_OPT:
 299       notlsopt = 1;
 300       break;
 301
 302     case OPTION_NO_TLS_GET_ADDR_OPT:
 303       params.no_tls_get_addr_opt = 1;
 304       break;
 305
 306     case OPTION_NEW_PLT:
 307       params.plt_style = PLT_NEW;
 308       break;
 309
 310     case OPTION_OLD_PLT:
 311       params.plt_style = PLT_OLD;
 312       break;
 313
 314     case OPTION_OLD_GOT:
 315       old_got = 1;
 316       break;
 317
 318     case OPTION_TRADITIONAL_FORMAT:
 319       notlsopt = 1;
 320       params.no_tls_get_addr_opt = 1;
 321       return FALSE;
 322
 323     case OPTION_PPC476_WORKAROUND:
 324       params.ppc476_workaround = 1;
 325       if (optarg != NULL)
 326         {
 327           char *end;
 328           pagesize = strtoul (optarg, &end, 0);
 329           if (*end
 330               || (pagesize < 4096 && pagesize != 0)
 331               || pagesize != (pagesize & -pagesize))
 332             einfo (_("%P%F: invalid pagesize `%s'\''\n"), optarg);
 333         }
 334       break;
 335
 336     case OPTION_NO_PPC476_WORKAROUND:
 337       params.ppc476_workaround = 0;
 338       break;
 339 '
 340
 341 # Put these extra ppc32elf routines in ld_${EMULATION_NAME}_emulation
 342 #
 343 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_after_open_output
 344 if test -z "$VXWORKS_BASE_EM_FILE" ; then
 345   LDEMUL_AFTER_OPEN=ppc_after_open
 346 fi
 347 LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
 348 LDEMUL_FINISH=ppc_finish