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2021-05-31 Nelson Chu <nelson.chu@sifive.com>
Lifang Xia <lifang_xia@c-sky.com>
The data segment phase exp_seg_relro_adjust means we are still adjusting the
relro segments, so we will get the symbol values which havn't consider the
relro. It is dangerous and we shouldn't do the relaxations at this stage.
Otherwise, we may get the truncated fails when the relax range crossing the
data segment.
One of the solution is that, we use a pointer to monitor the data segment
phase while relaxing, to know whether the relro has been handled or not.
Once we check the phase is exp_seg_relro_adjust, we should skip this round
of relaxations, since the incorrect symbol values will affect the correctness
of relaxations. I think we probably need to record more information about
data segment or alignments in the future, to make sure it is safe to doing
relaxations.
For the two new testcases, relro-relax-lui and relro-relax-pcrel, we get
the following truncated errors when using toolchains, which enable relro:
(.text+0x0): relocation truncated to fit: R_RISCV_GPREL_I against symbol `SymbolRodata' defined in .rodata section in test1.o
After applying this patch, the truncated errors should be resolved.
However, only linux toolchains support -z relro, so we only test these
two testcases when supporting shared library.
bfd/
PR 27566
* elfnn-riscv.c (struct riscv_elf_link_hash_table): New integer pointer
to monitor the data segment phase.
(bfd_elfNN_riscv_set_data_segment_info): New function called by
after_allocation, to set the data_segment_phase from expld.dataseg.
(_bfd_riscv_relax_section): Don't relax when data_segment_phase is
exp_seg_relro_adjust (0x4).
* elfxx-riscv.h (bfd_elf32_riscv_set_data_segment_info): New extern.
(bfd_elf64_riscv_set_data_segment_info): Likewise.
ld/
PR 27566
* emultempl/riscvelf.em (after_allocation): Call
riscv_set_data_segment_info to set data segment phase before relaxing.
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
* testsuite/ld-riscv-elf/relro-relax-lui.d: New testcase.
* testsuite/ld-riscv-elf/relro-relax-lui.s: Likewise.
* testsuite/ld-riscv-elf/relro-relax-pcrel.d: Likewise.
* testsuite/ld-riscv-elf/relro-relax-pcrel.s: Likewise.
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| emulparams | ||
| emultempl | ||
| po | ||
| scripttempl | ||
| testsuite | ||
| .gitignore | ||
| aclocal.m4 | ||
| ChangeLog | ||
| ChangeLog-0001 | ||
| ChangeLog-0203 | ||
| ChangeLog-2004 | ||
| ChangeLog-2005 | ||
| ChangeLog-2006 | ||
| ChangeLog-2007 | ||
| ChangeLog-2008 | ||
| ChangeLog-2009 | ||
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| ChangeLog-2011 | ||
| ChangeLog-2012 | ||
| ChangeLog-2013 | ||
| ChangeLog-2014 | ||
| ChangeLog-2015 | ||
| ChangeLog-2016 | ||
| ChangeLog-2017 | ||
| ChangeLog-2018 | ||
| ChangeLog-2019 | ||
| ChangeLog-2020 | ||
| ChangeLog-9197 | ||
| ChangeLog-9899 | ||
| config.in | ||
| configure | ||
| configure.ac | ||
| configure.host | ||
| configure.tgt | ||
| deffile.h | ||
| deffilep.y | ||
| dep-in.sed | ||
| elf-hints-local.h | ||
| fdl.texi | ||
| gen-doc.texi | ||
| genscrba.sh | ||
| genscripts.sh | ||
| h8-doc.texi | ||
| ld.h | ||
| ld.texi | ||
| ldbuildid.c | ||
| ldbuildid.h | ||
| ldcref.c | ||
| ldctor.c | ||
| ldctor.h | ||
| ldelf.c | ||
| ldelf.h | ||
| ldelfgen.c | ||
| ldelfgen.h | ||
| ldemul.c | ||
| ldemul.h | ||
| ldexp.c | ||
| ldexp.h | ||
| ldfile.c | ||
| ldfile.h | ||
| ldgram.y | ||
| ldint.texi | ||
| ldlang.c | ||
| ldlang.h | ||
| ldlex-wrapper.c | ||
| ldlex.h | ||
| ldlex.l | ||
| ldmain.c | ||
| ldmain.h | ||
| ldmisc.c | ||
| ldmisc.h | ||
| ldver.c | ||
| ldver.h | ||
| ldwrite.c | ||
| ldwrite.h | ||
| lexsup.c | ||
| libdep_plugin.c | ||
| MAINTAINERS | ||
| Makefile.am | ||
| Makefile.in | ||
| mri.c | ||
| mri.h | ||
| NEWS | ||
| pe-dll.c | ||
| pe-dll.h | ||
| pep-dll.c | ||
| pep-dll.h | ||
| plugin.c | ||
| plugin.h | ||
| README | ||
| stamp-h.in | ||
| sysdep.h | ||
| testplug2.c | ||
| testplug3.c | ||
| testplug4.c | ||
| testplug.c | ||
| TODO | ||
README for LD
This is the GNU linker. It is distributed with other "binary
utilities" which should be in ../binutils. See ../binutils/README for
more general notes, including where to send bug reports.
There are many features of the linker:
* The linker uses a Binary File Descriptor library (../bfd)
that it uses to read and write object files. This helps
insulate the linker itself from the format of object files.
* The linker supports a number of different object file
formats. It can even handle multiple formats at once:
Read two input formats and write a third.
* The linker can be configured for cross-linking.
* The linker supports a control language.
* There is a user manual (ld.texi), as well as the
beginnings of an internals manual (ldint.texi).
Installation
============
See ../binutils/README.
If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.
To build just the linker, make the target all-ld from the top level
directory (one directory above this one).
Porting to a new target
=======================
See the ldint.texi manual.
Reporting bugs etc
===========================
See ../binutils/README.
Known problems
==============
The Solaris linker normally exports all dynamic symbols from an
executable. The GNU linker does not do this by default. This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets). This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl. You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.
HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly. The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages. There are various
workarounds to this:
* Build and install bash, and build with "make SHELL=bash".
* Update to a version of HP/UX with a working shell (e.g., 9.05).
* Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
emulparams script used exports any shell variables it sets.
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