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PowerPC64 changes for xlc

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The changes to reorder sections for better relro protection on powerpc64,
3e2b0f31, 23283c1b, and 5ad18f16, run into a problem with xlc.
xlc -qdatalocal puts global variables into .toc, which means that .toc
must be writable.  The simplest way to accomplish this is to edit the
linker script to remove .toc sections from .got on detecting xlc object
files.

bfd/
	* elf64-ppc.h (struct ppc64_elf_params): Add "object_in_toc".
	* elf64-ppc.c (ppc64_elf_add_symbol_hook): Assume that global symbols
	in .toc indicate xlc compiled code that might require a rw .toc.
ld/
	* emulparams/elf64ppc.sh (INITIAL_READWRITE_SECTIONS): Define.
	* emultempl/ppc64elf.em (params): Init new field.
	(ppc_after_open): New function.
	(LDEMUL_AFTER_OPEN): Define.
	* ldlang.c (lang_final): Whitespace fix.
ld/testsuite/
	* ld-powerpc/tocvar.d, * ld-powerpc/tocvar.s: New test.
	* ld-powerpc/tocnovar.d, * ld-powerpc/tocnovar.s: New test.
	* ld-powerpc/powerpc.exp: Run tocvar and tocnovar.
This commit is contained in:
Alan Modra 2015-01-27 23:40:05 +10:30
parent 3f8107ab38
commit dbd1e97e32
13 changed files with 131 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
bfd/ChangeLog
View File

@ -1,3 +1,9 @@
2015-01-28 Alan Modra <amodra@gmail.com>
* elf64-ppc.h (struct ppc64_elf_params): Add "object_in_toc".
* elf64-ppc.c (ppc64_elf_add_symbol_hook): Assume that global symbols
in .toc indicate xlc compiled code that might require a rw .toc.
2015-01-28 James Bowman <james.bowman@ftdichip.com>
* Makefile.am: Add FT32 files.

8
bfd/elf64-ppc.c
View File

@ -4836,6 +4836,14 @@ ppc64_elf_add_symbol_hook (bfd *ibfd,
isym->st_shndx = SHN_UNDEF;
}
}
else if (*sec != NULL
&& strcmp ((*sec)->name, ".toc") == 0
&& ELF_ST_TYPE (isym->st_info) == STT_OBJECT)
{
struct ppc_link_hash_table *htab = ppc_hash_table (info);
if (htab != NULL)
htab->params->object_in_toc = 1;
}
if ((STO_PPC64_LOCAL_MASK & isym->st_other) != 0)
{

3
bfd/elf64-ppc.h
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@ -57,6 +57,9 @@ struct ppc64_elf_params
/* Whether to generate out-of-line register save/restore for gcc -Os code. */
int save_restore_funcs;
/* Set when a potential variable is detected in .toc. */
int object_in_toc;
};
bfd_boolean ppc64_elf_init_stub_bfd

8
ld/ChangeLog
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@ -1,3 +1,11 @@
2015-01-28 Alan Modra <amodra@gmail.com>
* emulparams/elf64ppc.sh (INITIAL_READWRITE_SECTIONS): Define.
* emultempl/ppc64elf.em (params): Init new field.
(ppc_after_open): New function.
(LDEMUL_AFTER_OPEN): Define.
* ldlang.c (lang_final): Whitespace fix.
2015-01-28 James Bowman <james.bowman@ftdichip.com>
* Makefile.am: Add FT32 files.

2
ld/emulparams/elf64ppc.sh
View File

@ -38,6 +38,8 @@ OTHER_RELRO_SECTIONS_2="
.opd ${RELOCATING-0} :${RELOCATING+ ALIGN(8)} { KEEP (*(.opd)) }
.toc1 ${RELOCATING-0} :${RELOCATING+ ALIGN(8)} { *(.toc1) }
.branch_lt ${RELOCATING-0} :${RELOCATING+ ALIGN(8)} { *(.branch_lt) }"
INITIAL_READWRITE_SECTIONS="
.toc ${RELOCATING-0} :${RELOCATING+ ALIGN(8)} { *(.toc) }"
# Put .got before .data
DATA_GOT=" "
# Always make .got read-only after relocation

38
ld/emultempl/ppc64elf.em
View File

@ -39,7 +39,7 @@ static struct ppc64_elf_params params = { NULL,
&ppc_layout_sections_again,
1, 0, 0,
${DEFAULT_PLT_STATIC_CHAIN-0}, -1, 0,
0, -1, -1};
0, -1, -1, 0};
/* Fake input file for stubs. */
static lang_input_statement_type *stub_file;
@ -98,6 +98,37 @@ ppc_create_output_section_statements (void)
einfo ("%F%P: can not init BFD: %E\n");
}
/* Called after opening files but before mapping sections. */
static void
ppc_after_open (void)
{
if (stub_file != NULL && link_info.relro && params.object_in_toc)
{
/* We have a .toc section that might be written to at run time.
Don't put .toc into the .got output section. */
lang_output_section_statement_type *got;
got = lang_output_section_find (".got");
if (got != NULL)
{
lang_statement_union_type *s;
for (s = got->children.head; s != NULL; s = s->header.next)
if (s->header.type == lang_wild_statement_enum
&& s->wild_statement.filename == NULL)
{
struct wildcard_list **i = &s->wild_statement.section_list;
while (*i != NULL)
if (strcmp ((*i)->spec.name, ".toc") == 0)
*i = (*i)->next;
else
i = &(*i)->next;
}
}
}
gld${EMULATION_NAME}_after_open ();
}
/* Move the input section statement at *U which happens to be on LIST
to be just before *TO. */
@ -874,8 +905,9 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
# Put these extra ppc64elf routines in ld_${EMULATION_NAME}_emulation
#
LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern
LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
LDEMUL_AFTER_OPEN=ppc_after_open
LDEMUL_BEFORE_ALLOCATION=ppc_before_allocation
LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
LDEMUL_FINISH=gld${EMULATION_NAME}_finish
LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=ppc_create_output_section_statements
LDEMUL_NEW_VERS_PATTERN=gld${EMULATION_NAME}_new_vers_pattern

1
ld/ldlang.c
View File

@ -6295,7 +6295,6 @@ lang_final (void)
new_stmt = new_stat (lang_output_statement, stat_ptr);
new_stmt->name = output_filename;
}
/* Reset the current counters in the regions. */

6
ld/testsuite/ChangeLog
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@ -1,3 +1,9 @@
2015-01-28 Alan Modra <amodra@gmail.com>
* ld-powerpc/tocvar.d, * ld-powerpc/tocvar.s: New test.
* ld-powerpc/tocnovar.d, * ld-powerpc/tocnovar.s: New test.
* ld-powerpc/powerpc.exp: Run tocvar and tocnovar.
2015-01-28 Senthil Kumar Selvaraj <senthil_kumar.selvaraj@atmel.com>
* ld-scripts/memory.t: Define new symbol tred.

2
ld/testsuite/ld-powerpc/powerpc.exp
View File

@ -320,3 +320,5 @@ run_dump_test "attr-gnu-12-11"
run_dump_test "attr-gnu-12-21"
run_dump_test "vle-multiseg-6"
run_dump_test "tocvar"
run_dump_test "tocnovar"

14
ld/testsuite/ld-powerpc/tocnovar.d Normal file
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@ -0,0 +1,14 @@
#source: tocnovar.s
#as: -a64
#ld: -melf64ppc -z relro
#readelf: -l --wide
#target: powerpc64*-*-*
#...
+LOAD .*
+LOAD .*
+GNU_RELRO .*
#...
+00 +\.text
+01 +\.opd \.got
+02 +\.opd \.got

16
ld/testsuite/ld-powerpc/tocnovar.s Normal file
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@ -0,0 +1,16 @@
.section .opd,"aw",@progbits
.global _start
.type _start,@function
_start:
.quad .L_start, .TOC.@tocbase, 0
.text
.L_start:
lwz 3,x@toc(2)
b _start
.size _start,.-.L_start
.section .toc,"aw",@progbits
.type x,@object
x: .long 0
.size x,.-x

14
ld/testsuite/ld-powerpc/tocvar.d Normal file
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@ -0,0 +1,14 @@
#source: tocvar.s
#as: -a64
#ld: -melf64ppc -z relro
#readelf: -l --wide
#target: powerpc64*-*-*
#...
+LOAD .*
+LOAD .*
+GNU_RELRO .*
#...
+00 +\.text
+01 +\.opd \.toc
+02 +\.opd

17
ld/testsuite/ld-powerpc/tocvar.s Normal file
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@ -0,0 +1,17 @@
.section .opd,"aw",@progbits
.global _start
.type _start,@function
_start:
.quad .L_start, .TOC.@tocbase, 0
.text
.L_start:
lwz 3,x@toc(2)
b _start
.size _start,.-.L_start
.section .toc,"aw",@progbits
.global x
.type x,@object
x: .long 0
.size x,.-x