When -z mark-plt is used to add DT_X86_64_PLT, DT_X86_64_PLTSZ and
DT_X86_64_PLTENT, the r_addend field of the R_X86_64_JUMP_SLOT relocation
stores the offset of the indirect branch instruction. However, glibc
versions which don't have this commit in glibc 2.36:
commit f8587a61892cbafd98ce599131bf4f103466f084
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri May 20 19:21:48 2022 -0700
x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
can ignore their r_addends.
Reviewed-by: Fangrui Song <maskray@google.com>
won't ignore the r_addend value in the R_X86_64_JUMP_SLOT relocation.
Although this commit has been backported to glibc 2.33/2.34/2.35 release
branches, it is safer to require glibc 2.36 for such binaries.
Extend the glibc version dependency of GLIBC_ABI_DT_RELR for DT_RELR to
also add GLIBC_2.36 version dependency for -z mark-plt on the shared C
library if it provides a GLIBC_2.XX symbol version.
* elflink.c (elf_find_verdep_info): Moved to ...
* elf-bfd.h (elf_find_verdep_info): Here.
(elf_backend_data): Add elf_backend_add_glibc_version_dependency.
(_bfd_elf_link_add_glibc_version_dependency): New function.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
* elf64-x86-64.c (elf_x86_64_add_glibc_version_dependency):
Likewise.
(elf_backend_add_glibc_version_dependency): New.
* elflink.c (elf_link_add_dt_relr_dependency): Renamed to ...
(elf_link_add_glibc_verneed): This. Modified to support other
glibc dependencies.
(_bfd_elf_link_add_glibc_version_dependency): Likewise.
(_bfd_elf_link_add_dt_relr_dependency): Likewise.
(bfd_elf_size_dynamic_sections): Call
elf_backend_add_glibc_version_dependency instead of
elf_link_add_dt_relr_dependency.
* elfxx-target.h (elf_backend_add_glibc_version_dependency): New.
(elfNN_bed): Add elf_backend_add_glibc_version_dependency.
ld/
* testsuite/ld-x86-64/mark-plt-1a.rd: New file.
* testsuite/ld-x86-64/mark-plt-1b.rd: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run -z mark-plt test for
GLIBC_2.36 dependency.
While having been moved a couple of times since its introduction in
f6c7c3e8b742 ("Referencing a function's address on PowerPC64 ELFv2"),
the wording has always remained the same. In particular ELFv1 and ELFv2
have always been the wrong way round.
This patch adds linker support to patch R_BPF_64_NODYLD32 relocations.
The implementation was based on comments and code in LLVM, as the GNU
toolchain does not uses this relocation type.
Also recognized are aarch64-*-gnu tagrets, e.g. aarch64-pc-gnu or
aarch64-unknown-gnu.
The ld/emulparams/aarch64gnu.sh file is (for now) identical to aarch64fbsd.sh,
or to aarch64linux.sh with Linux-specific logic removed; and mainly different
from the generic aarch64elf.sh in that it does not set EMBEDDED=yes.
Coupled with a corresponding GCC patch, this produces a toolchain that can
sucessfully build working binaries targeting aarch64-gnu.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
In commit 83c79df86bf4 I removed configure tests for strtoull among
other library functions part of C99, but didn't remove what is now
dead code.
* bfd.c (bfd_scan_vma): Delete fall-back for strtoull.
Adds two new external authors to etc/update-copyright.py to cover
bfd/ax_tls.m4, and adds gprofng to dirs handled automatically, then
updates copyright messages as follows:
1) Update cgen/utils.scm emitted copyrights.
2) Run "etc/update-copyright.py --this-year" with an extra external
author I haven't committed, 'Kalray SA.', to cover gas testsuite
files (which should have their copyright message removed).
3) Build with --enable-maintainer-mode --enable-cgen-maint=yes.
4) Check out */po/*.pot which we don't update frequently.
With old "medium" code model, we call a function with a pair of PCALAU12I
and JIRL instructions. The assembler produces something like:
8: 1a00000c pcalau12i $t0, 0
8: R_LARCH_PCALA_HI20 g
c: 4c000181 jirl $ra, $t0, 0
c: R_LARCH_PCALA_LO12 g
The linker generates a "PLT entry" for data without any diagnostic.
If "g" is a data symbol and ld with -shared option, it may load two
instructions in the PLT.
Without -shared option, loongarch_elf_adjust_dynamic_symbol can delete PLT
entry.
For R_LARCH_PCALA_HI20 relocation, linker only generate PLT entry for STT_FUNC
and STT_GNU_IFUNC symbols.
Add tls le relax support and related relocs in bfd.
New relocation related explanation can refer to the following url:
https://github.com/loongson/la-abi-specs/blob/release/laelf.adoc
This support does two main things:
1. Implement support for three new relocation items in bfd.
The three new relocation items are shown below:
R_LARCH_TLS_LE_ADD_R
R_LARCH_TLS_LE_HI20_R
R_LARCH_TLS_LE_LO12_R
2. ADD a new macro RELOCATE_TLS_TP32_HI20
Handle problems caused by symbol extensions in TLS LE, The processing
is similar to the macro RELOCATE_CALC_PC32_HI20 method.
3. Implement the tls le relax function.
bfd/ChangeLog:
* bfd-in2.h: Add relocs related to tls le relax.
* elfnn-loongarch.c:
(loongarch_relax_tls_le): New function.
(RELOCATE_TLS_TP32_HI20): New macro.
(loongarch_elf_check_relocs): Add new reloc support.
(perform_relocation): Likewise.
(loongarch_elf_relocate_section): Handle new relocs related to relax.
(loongarch_elf_relax_section): Likewise.
* elfxx-loongarch.c:
(LOONGARCH_HOWTO (R_LARCH_TLS_LE_ADD_R)): New reloc how to type.
(LOONGARCH_HOWTO (R_LARCH_TLS_LE_HI20_R)): Likewise.
(LOONGARCH_HOWTO (R_LARCH_TLS_LE_LO12_R)): Likewise.
* libbfd.h: Add relocs related to tls le relax.
* reloc.c: Likewise.
For
add name@gottpoff(%rip), %reg
mov name@gottpoff(%rip), %reg
add
# define R_X86_64_CODE_4_GOTTPOFF 44
and for
lea name@tlsdesc(%rip), %reg
add
# define R_X86_64_CODE_4_GOTPC32_TLSDESC 45
if the instruction starts at 4 bytes before the relocation offset.
They are similar to R_X86_64_GOTTPOFF and R_X86_64_GOTPC32_TLSDESC,
respectively. Linker can covert GOTTPOFF to
add $name@tpoff, %reg
mov $name@tpoff, %reg
and GOTPC32_TLSDESC to
mov $name@tpoff, %reg
mov name@gottpoff(%rip), %reg
if the instruction is encoded with the REX2 prefix when possible.
bfd/
* elf64-x86-64.c (x86_64_elf_howto_table): Add
R_X86_64_CODE_4_GOTTPOFF and R_X86_64_CODE_4_GOTPC32_TLSDESC.
(R_X86_64_standard): Updated.
(x86_64_reloc_map): Add BFD_RELOC_X86_64_CODE_4_GOTTPOFF
and BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC.
(elf_x86_64_check_tls_transition): Handle R_X86_64_CODE_4_GOTTPOFF
and R_X86_64_CODE_4_GOTPC32_TLSDESC.
(elf_x86_64_tls_transition): Likewise.
(elf_x86_64_scan_relocs): Likewise.
(elf_x86_64_relocate_section): Likewise.
* reloc.c (bfd_reloc_code_real): Add
BFD_RELOC_X86_64_CODE_4_GOTTPOFF and
BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC.
* bfd-in2.h: Regenerated.
* libbfd.h: Likewise.
gas/
* config/tc-i386.c (tc_i386_fix_adjustable): Handle
BFD_RELOC_X86_64_CODE_4_GOTTPOFF and
BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC.
(md_assemble): Handle BFD_RELOC_X86_64_CODE_4_GOTTPOFF.
(output_insn): Don't add empty REX prefix with REX2 prefix.
(output_disp): Handle BFD_RELOC_X86_64_CODE_4_GOTTPOFF and
BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC.
(md_apply_fix): Likewise.
(i386_validate_fix): Generate BFD_RELOC_X86_64_CODE_4_GOTTPOFF or
BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC if ixp->fx_tcbit3 is set.
(tc_gen_reloc): Handle BFD_RELOC_X86_64_CODE_4_GOTTPOFF and
BFD_RELOC_X86_64_CODE_4_GOTPC32_TLSDESC.
* testsuite/gas/i386/x86-64-gottpoff.d: New file.
* testsuite/gas/i386/x86-64-gottpoff.s: Likewise.
* testsuite/gas/i386/x86-64-tlsdesc.d: Likewise.
* testsuite/gas/i386/x86-64-tlsdesc.s: Likewise.
include/
* elf/x86-64.h (elf_x86_64_reloc_type): Add
R_X86_64_CODE_4_GOTTPOFF and R_X86_64_CODE_4_GOTPC32_TLSDESC
ld/
* testsuite/ld-x86-64/tlsbindesc.d: Updated.
* testsuite/ld-x86-64/tlsbindesc.rd: Likewise.
* testsuite/ld-x86-64/tlsbindesc.s: Add R_X86_64_CODE_4_GOTTPOFF
and R_X86_64_CODE_4_GOTPC32_TLSDESC tests.
* Problematic fix commit,
2029e13917d53d2289d3ebb390c4f40bd2112d21
RISC-V: Clarify the behaviors of SET/ADD/SUB relocations
* Bugzilla,
https://sourceware.org/bugzilla/show_bug.cgi?id=31179#c5
The addend of SUB_ULEB128 should be zero if using .uleb128, but we make it
non-zero by accident in assembler before. This causes troubles by applying
the above commit, since the calculation is changed to support .reloc *SUB*
relocations with non-zero addend.
We encourage people to rebuild their stuff to get the non-zero addend of
SUB_ULEB128, but that might need some times, so report warnings to inform
people need to rebuild their stuff if --check-uleb128 is enabled.
Since the failed .reloc cases for ADD/SET/SUB/ULEB128 are rarely to use,
it may acceptable that stop supproting them until people rebuld their stuff,
maybe half-year or a year later. Or maybe we should teach people that don't
write the .reloc R_RISCV_SUB* with non-zero constant, and then report
warnings/errors in assembler.
bfd/
* elfnn-riscv.c (perform_relocation): Ignore the non-zero addend of
R_RISCV_SUB_ULEB128.
(riscv_elf_relocate_section): Report warnings to inform people need
to rebuild their stuff if --check-uleb128 is enabled. So that can
get the right non-zero addend of R_RISCV_SUB_ULEB128.
* elfxx-riscv.h (struct riscv_elf_params): Added bool check_uleb128.
ld/
* NEWS: Updated.
* emultempl/riscvelf.em: Added linker risc-v target options,
--[no-]check-uleb128, to enable/disable checking if the addend of
uleb128 is non-zero or not. So that people will know they need to
rebuild the objects with binutils 2.42 and up, to get the right zero
addend of SUB_ULEB128 relocation, or they may get troubles if using
.reloc.
* ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
* ld/testsuite/ld-riscv-elf/pr31179*: New test cases.
Seen when running ld-loongarch-elf/tlsdesc-dso test.
elfxx-loongarch.c:1844:32: runtime error: index 125 out of bounds for
type 'loongarch_reloc_howto_type [124]'
So either the loongarch_howto_table needs three more
LOONGARCH_EMPTY_HOWTO entries, or loongarch_elf_rtype_to_howto should
be testing for r_type < ARRAY_SIZE (loongarch_howto_table). I figure
it's worth wasting a little more space to get faster lookup.
* elfxx-loongarch.c (loongarch_howto_table): Add
LOONGARCH_EMPTY_HOWTO entries for 121..123.
(loongarch_elf_rtype_to_howto): Don't support slow lookup.
Assert exact table size and r_type indexing. Omit return cast.
(loongarch_reloc_name_lookup): Omit assertion and return cast.
(loongarch_reloc_type_lookup): Likewise.
1.The linker for each DESC generates a R_LARCH_TLS_DESC64 dynamic
relocation, which relocation is placed at .rela.dyn.
TLSDESC always allocates two GOT slots and one dynamic relocation
space to TLSDESC.
2. When using multiple ways to access the same TLS variable, a
maximum of 5 GOT slots are used. For example, using GD, TLSDESC,
and IE to access the same TLS variable, GD always uses the first
two of the five GOT, TLSDESC uses the third and fourth, and IE
uses the last.
If the symbol index is not zero, the addend is used to represent
the first and the third expressions of the .align.
The lowest 8 bits are used to represent the first expression.
Other bits are used to represent the third expression.
The addend of R_LARCH_ALIGN for ".align 5, ,4" is 0x405.
The addend of R_LARCH_ALIGN for ".balign 32, ,4" is 0x405.
Revert most of this patch, it isn't correct to free the BFD_IN_MEMORY
iostream in io_reinit.
PR 31145
* format.c (io_reinit): Revert last change. Comment.
* opncls.c (_bfd_delete_bfd): Likewise.
Even in shared objects, la.got -> la.pcrel relaxation can still be
performed for symbols with hidden visibility. For example, if a.c is:
extern int x;
int f() { return x++; }
and b.c is:
int x = 114514;
If compiling and linking with:
gcc -shared -fPIC -O2 -fvisibility=hidden a.c b.c
Then the la.got in a.o should be relaxed to la.pcrel, and the resulted f
should be like:
pcaddi $t0, x
ldptr.w $a0, $t0, 0
addi.w $t1, $a0, 1
stptr.w $t1, $t0, 0
ret
Remove bfd_link_executable from the condition of la.got -> la.pcrel
relaxation so this will really happen. The SYMBOL_REFERENCES_LOCAL
check is enough not to wrongly relax preemptable symbols (for e.g.
when -fvisibility=hidden is not used).
Note that on x86_64 this is also relaxed and the produced code is like:
lea x(%rip), %rdx
mov (%rdx), %rax
lea 1(%rax), %ecx
mov %ecx, (%rdx)
ret
Tested by running ld test suite, bootstrapping and regtesting GCC with
the patched ld, and building and testing Glibc with the patched ld. No
regression is observed.
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
R_LARCH_CALL36 is used for medium code model function call pcaddu18i+jirl, and
these two instructions must adjacent.
The LoongArch ABI v2.20 at here: https://github.com/loongson/la-abi-specs.
