binutils-gdb/ld
Andreas Krebbel afca762f59 S/390: Improve partial relro support for 64 bit
Currently on S/390 the .got.plt always comes first which prevents the
GNU_RELRO segment from being extended across the non-plt GOT entries.

Just swapping both unfortunately is not that simple since our ABI
requires the _GLOBAL_OFFSET_TABLE_ symbol to point to the very
beginning of the entire GOT. Of the 3 magic GOT entries the first is
accessed via got pointer while second and third are being accessed via
DT_PLTGOT.  In order to keep them together we make DT_PLTGOT to point
to the .got instead of .got.plt.  However, this violates an assumption
in the dynamic linker prelink undo code about the GOTPLT entries
starting at DT_PLTGOT + 3.  We got rid of this requirement with a
Glibc patch already in version 2.24:
https://sourceware.org/ml/libc-alpha/2016-06/msg01302.html

So the S/390 relro GOT layout will look like this with this patch:

      +----------------------------------+
      |got[0]: DYNAMIC                   |   <--- _GLOBAL_OFFSET_TABLE_ == DT_PLTGOT .got
      |got[1]: link_map parm             |
      |got[2]: &_dl_runtime_resolve      |
      +----------------------------------+
      |                                  |   non-plt GOT entries
      |                                  |
      |                                  |
      +----------------------------------+
      |                                  |   <--- .gotplt, PLT GOT entries
      |                                  |
      |                                  |
      |                                  |
      +----------------------------------+

The patch detects the current layout in size_dynamic_section in order
to deal also with linker scripts not generated by this ld version.
With partial relro enabled we pick a linker script where .got and
.got.plt are swapped which then triggers the rest of the logic.

ld/ChangeLog:

2018-07-18  Andreas Krebbel  <krebbel@linux.ibm.com>

	* emulparams/elf64_s390.sh: Define GENERATE_RELRO_SCRIPT and
	SEPARATE_GOTPLT.
	* testsuite/ld-s390/gotreloc_64-relro-1.dd: New test.
	* testsuite/ld-s390/gotreloc_64-norelro-1.dd: Renamed from ...
	* testsuite/ld-s390/gotreloc_64-1.dd: ... this.
	* testsuite/ld-s390/s390.exp: Split the GOT testcase into two.

bfd/ChangeLog:

2018-07-18  Andreas Krebbel  <krebbel@linux.ibm.com>

	* elf-s390-common.c (s390_gotplt_after_got_p): New function.
	(s390_got_pointer): New function.
	(s390_got_offset): New function.
	(s390_gotplt_offset): New function.
	* elf64-s390.c (allocate_dynrelocs): Adjust comment.
	(elf_s390_size_dynamic_sections): Move space for magic GOT entries
	from .got.plt to .got if necessary and pick the right location for
	_GLOBAL_OFFSET_TABLE_.
	(elf_s390_relocate_section): Use the wrapper functions from
	elf-s390-common.c to deal with both possible layouts (either .got
	or .got.plt first).
	(elf_s390_finish_dynamic_sections): Likewise.
	(elf_s390_finish_dynamic_symbol): Make the location of the GOT
	magic entries conditional.
2018-07-18 13:20:06 +02:00
..
emulparams S/390: Improve partial relro support for 64 bit 2018-07-18 13:20:06 +02:00
emultempl ld: Enable using separate linker script for -z relro 2018-07-18 13:20:06 +02:00
po Updated French translation for gold and Spanish translation for ld. 2018-07-18 08:37:38 +01:00
scripttempl
testsuite S/390: Improve partial relro support for 64 bit 2018-07-18 13:20:06 +02:00
.gitignore
aclocal.m4 Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ChangeLog Updated French translation for gold and Spanish translation for ld. 2018-07-18 08:37:38 +01:00
ChangeLog-0001
ChangeLog-0203
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ChangeLog-2008
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config.in Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
configure Regenerate configure and pot files with updated binutils version number. 2018-06-24 19:13:01 +01:00
configure.ac Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
configure.host
configure.tgt RISC-V: Add riscv-*-* configure support, and minor cleanup. 2018-07-05 17:49:11 -07:00
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
genscrba.sh
genscripts.sh ld: Enable using separate linker script for -z relro 2018-07-18 13:20:06 +02:00
h8-doc.texi Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ld.h
ld.texi Fix use of "command line X" in binutils doc 2018-07-02 11:18:24 +01:00
ldbuildid.c
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldemul.c
ldemul.h
ldexp.c LD: Export relative-from-absolute symbol marking to BFD 2018-07-17 20:04:53 +01:00
ldexp.h
ldfile.c
ldfile.h
ldgram.y
ldint.texi Fix use of "command line X" in binutils doc 2018-07-02 11:18:24 +01:00
ldlang.c ld: Set non_ir_ref_regular for --undefined SYMBOL 2018-07-04 06:29:13 -07:00
ldlang.h
ldlex-wrapper.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldlex.h
ldlex.l
ldmain.c
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c ld: Properly display default for -z separate-code 2018-07-04 06:22:51 -07:00
MAINTAINERS
Makefile.am Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
Makefile.in Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
mri.c
mri.h
NEWS Fix use of "command line X" in binutils doc 2018-07-02 11:18:24 +01:00
pe-dll.c
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c ld: Set non_ir_ref_regular for --undefined SYMBOL 2018-07-04 06:29:13 -07:00
plugin.h
README Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
stamp-h.in
sysdep.h
testplug2.c
testplug3.c
testplug4.c
testplug.c
TODO 19990502 sourceware import 1999-05-03 07:29:11 +00:00

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		README for LD

This is the GNU linker.  It is distributed with other "binary
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  * Update to a version of HP/UX with a working shell (e.g., 9.05).
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