old-cross-binutils/ld/emultempl/ppc32elf.em
Alan Modra d3e454b956 PowerPC non-PIC to PIC editing for protected var access
This is a linker-only solution to the incompatibility between shared
library protected visibility variables and using .dynbss and copy
relocs for non-PIC access to shared library variables.

bfd/
	* elf32-ppc.c (struct ppc_elf_link_hash_entry): Add has_addr16_ha
	and has_addr16_lo.  Make has_sda_refs a bitfield.
	(ppc_elf_check_relocs): Set new flags.
	(ppc_elf_link_hash_table_create): Update default_params.
	(ppc_elf_adjust_dynamic_symbol): Clear protected_def in cases
	where we won't be making .dynbss entries or editing code.  Set
	params->pic_fixup when we'll edit code for protected var access.
	(allocate_dynrelocs): Allocate got entry for edited code and
	discard dyn_relocs.
	(struct ppc_elf_relax_info): Add picfixup_size.
	(ppc_elf_relax_section): Rename struct one_fixup to struct
	one_branch_fixup.  Rename fixups to branch_fixups.  Size space for
	pic fixups.
	(ppc_elf_relocate_section): Edit non-PIC accessing protected
	visibility variables to PIC.  Don't emit dyn_relocs for code
	we've edited.
	* elf32-ppc.h (struct ppc_elf_params): Add pic_fixup.
ld/
	* emultempl/ppc32elf.em: Handle --no-pic-fixup.
	(params): Init new field.
	(ppc_before_allocation): Enable relaxation for pic_fixup.
2015-04-07 23:00:07 +09:30

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Text

# This shell script emits a C file. -*- C -*-
# Copyright (C) 2003-2015 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 "libbfd.h"
#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 bfd_vma pagesize = 0;
static struct ppc_elf_params params = { PLT_UNSET, -1, 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 || link_info.shared;
if (pagesize == 0)
pagesize = config.commonpagesize;
params.pagesize_p2 = bfd_log2 (pagesize);
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)
'
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 },
'
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"
));
'
PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
case OPTION_STUBSYMS:
params.emit_stub_syms = 1;
break;
case OPTION_NO_STUBSYMS:
params.emit_stub_syms = 0;
break;
case OPTION_NO_TLS_OPT:
notlsopt = 1;
break;
case OPTION_NO_TLS_GET_ADDR_OPT:
params.no_tls_get_addr_opt = 1;
break;
case OPTION_NEW_PLT:
params.plt_style = PLT_NEW;
break;
case OPTION_OLD_PLT:
params.plt_style = PLT_OLD;
break;
case OPTION_OLD_GOT:
old_got = 1;
break;
case OPTION_TRADITIONAL_FORMAT:
notlsopt = 1;
params.no_tls_get_addr_opt = 1;
return FALSE;
case OPTION_PPC476_WORKAROUND:
params.ppc476_workaround = 1;
if (optarg != NULL)
{
char *end;
pagesize = strtoul (optarg, &end, 0);
if (*end
|| (pagesize < 4096 && pagesize != 0)
|| pagesize != (pagesize & -pagesize))
einfo (_("%P%F: invalid pagesize `%s'\''\n"), optarg);
}
break;
case OPTION_NO_PPC476_WORKAROUND:
params.ppc476_workaround = 0;
break;
case OPTION_NO_PICFIXUP:
params.pic_fixup = -1;
break;
'
# Put these extra ppc32elf routines in ld_${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