Since converting load to mov needs to rewrite the REX byte and we don't
know if there is a REX byte with GOTPCREL relocation, do it only for
GOTPCRELX relocations.
bfd/
PR ld/27016
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Convert load
to mov only for GOTPCRELX relocations.
ld/
PR ld/27016
* testsuite/ld-x86-64/x86-64.exp: Run pr27016a and pr27016b.
* testsuite/ld-x86-64/pr27016a.d: New file.
* testsuite/ld-x86-64/pr27016a.s: Likewise.
* testsuite/ld-x86-64/pr27016b.d: Likewise.
* testsuite/ld-x86-64/pr27016b.s: Likewise.
All ELF backends with TLS descriptor support have
/* The offset into splt of the PLT entry for the TLS descriptor
resolver. Special values are 0, if not necessary (or not found
to be necessary yet), and -1 if needed but not determined
yet. */
bfd_vma tlsdesc_plt;
/* The GOT offset for the lazy trampoline. Communicated to the
loader via DT_TLSDESC_GOT. The magic value (bfd_vma) -1
indicates an offset is not allocated. */
bfd_vma tlsdesc_got;
in symbol hash entry. Move tlsdesc_plt/tlsdesc_got to elf_link_hash_entry
to reduce code duplication.
* elf-bfd.h (elf_link_hash_entry): Add tlsdesc_plt and
tlsdesc_got.
* elf32-arm.c (elf32_arm_link_hash_table): Remove tlsdesc_plt
and dt_tlsdesc_got.
(elf32_arm_size_dynamic_sections): Updated. Clear
root.tlsdesc_plt for DF_BIND_NOW.
(elf32_arm_finish_dynamic_sections): Updated.
(elf32_arm_output_arch_local_syms): Likewise.
* elf32-nds32.c (nds32_elf_size_dynamic_sections): Updated.
Clear root.tlsdesc_plt for DF_BIND_NOW.
(nds32_elf_finish_dynamic_sections): Updated.
* elf32-nds32.h (elf_nds32_link_hash_table): Remove
dt_tlsdesc_plt and dt_tlsdesc_got.
* elf64-x86-64.c (elf_x86_64_finish_dynamic_sections): Updated.
* elfnn-aarch64.c (elf_aarch64_link_hash_table): Remove
tlsdesc_plt and dt_tlsdesc_got.
(elfNN_aarch64_allocate_dynrelocs): Updated.
(elfNN_aarch64_finish_dynamic_sections): Likewise.
(elfNN_aarch64_size_dynamic_sections): Updated. Clear
root.tlsdesc_plt for DF_BIND_NOW. Don't check DF_BIND_NOW
twice.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Updated.
(_bfd_x86_elf_size_dynamic_sections): Likewise.
(_bfd_x86_elf_finish_dynamic_sections): Likewise.
* elfxx-x86.h (elf_x86_link_hash_table): Remove tlsdesc_plt and
tlsdesc_got.
Don't do anything special with non-loaded, non-alloced sections.
In particular, any relocs in such sections should not affect GOT
and PLT reference counting (ie. we don't allow them to create GOT
or PLT entries), there's no possibility or desire to optimize TLS
relocs, and there's not much point in propagating relocs to shared
libs that the dynamic linker won't relocate.
Since check_relocs is no longer called on non-loaded, non-alloced
sections, remove SEC_ALLOC check. Resolve relocation in debug section
against symbol defined in shared library to 0.
bfd/
PR ld/26080
* elf-m10300.c (mn10300_elf_relocate_section): Resolve relocation
in debug section against symbol defined in shared library to 0.
* elf32-i386.c (elf_i386_check_relocs): Remove SEC_ALLOC check.
* elf32-lm32.c (lm32_elf_check_relocs): Likewise.
* elf32-m32r.c (m32r_elf_check_relocs): Likewise.
* elf32-nds32.c (nds32_elf_check_relocs): Likewise.
* elf32-nios2.c (nios2_elf32_check_relocs): Likewise.
* elf32-or1k.c (or1k_elf_check_relocs): Likewise.
* elf32-ppc.c (ppc_elf_check_relocs): Likewise.
* elf32-sh.c (sh_elf_check_relocs): Likewise.
* elf32-xtensa.c (elf_xtensa_check_relocs): Likewise.
* elf64-alpha.c (elf64_alpha_check_relocs): Likewise.
* elf64-ppc.c (ppc64_elf_check_relocs): Likewise.
* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.
* elfxx-mips.c (_bfd_mips_elf_check_relocs): Likewise.
* elf32-vax.c (elf_vax_check_relocs): Set non_got_ref for non-GOT
reference.
(elf_vax_adjust_dynamic_symbol): Generate a copy reloc only if
there is non-GOT reference.
* elflink.c (_bfd_elf_link_check_relocs): Skip non-loaded,
non-alloced sections.
ld/
PR ld/26080
* testsuite/ld-elf/comm-data.exp: Remove copy_reloc.
* testsuite/ld-elf/comm-data2r.rd: Removed.
* testsuite/ld-elf/comm-data2r.sd: Likewise.
* testsuite/ld-elf/comm-data2r.xd: Likewise.
Since value of non-preemptible absolute symbol (SHN_ABS) won't change,
only relocations, which can be resolved as absolute value + addend, and
GOTPCREL relocations, where absolute value + addend is stored in the GOT
slot, against non-preemptible absolute symbol are allowed in PIE and
shared library.
Also convert load relocation to R_386_32, R_X86_64_32S or R_X86_64_32 for
relocation against non-preemptible absolute symbol. Don't convert to
R_X86_64_32S nor R_X86_64_32 for non-preemptible absolute symbol if they
overflow.
bfd/
PR ld/25749
PR ld/25754
* elf32-i386.c (elf_i386_convert_load_reloc): Convert load
relocation to R_386_32 for relocation against non-preemptible
absolute symbol.
(elf_i386_check_relocs): Call _bfd_elf_x86_valid_reloc_p. Don't
allocate dynamic relocation for non-preemptible absolute symbol.
(elf_i386_relocate_section): Pass sec to
GENERATE_DYNAMIC_RELOCATION_P.
* elf64-x86-64.c (R_X86_64_converted_reloc_bit): Moved.
(elf_x86_64_convert_load_reloc): Covert load relocation to
R_X86_64_32S or R_X86_64_32 for relocation against non-preemptible
absolute symbol. Don't convert to R_X86_64_32S nor R_X86_64_32
for non-preemptible absolute symbol if they overflow.
(elf_x86_64_check_relocs): Call _bfd_elf_x86_valid_reloc_p. Set
tls_type for GOT slot to GOT_ABS for non-preemptible absolute
symbol. Don't allocate dynamic relocation for non-preemptible
absolute symbol.
(elf_x86_64_relocate_section): Don't generate relative relocation
for GOTPCREL relocations aganst local absolute symbol. Pass sec
to GENERATE_DYNAMIC_RELOCATION_P.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): No dynamic relocation
against non-preemptible absolute symbol.
(_bfd_elf_x86_valid_reloc_p): New function.
(_bfd_x86_elf_size_dynamic_sections): No dynamic relocation for
GOT_ABS GOT slot.
* elfxx-x86.h (GENERATE_DYNAMIC_RELOCATION_P): Add an SEC
argument. Don't generate dynamic relocation against
non-preemptible absolute symbol.
(ABS_SYMBOL_P): New.
(GENERATE_RELATIVE_RELOC_P): Don't generate relative relocation
against non-preemptible absolute symbol.
(GOT_ABS): New.
(R_X86_64_converted_reloc_bit): New. Moved from elf64-x86-64.c.
(_bfd_elf_x86_valid_reloc_p): New.
ld/
PR ld/25749
PR ld/25754
* testsuite/ld-elf/linux-x86.exp: Run ld/25749 tests.
* testsuite/ld-elf/pr25749-1.c: New file.
* testsuite/ld-elf/pr25749-1a.c: Likewise.
* testsuite/ld-elf/pr25749-1b.c: Likewise.
* testsuite/ld-elf/pr25749-1b.err: Likewise.
* testsuite/ld-elf/pr25749-1c.c: Likewise.
* testsuite/ld-elf/pr25749-1d.c: Likewise.
* testsuite/ld-elf/pr25749-2.c: Likewise.
* testsuite/ld-elf/pr25749-2a.s: Likewise.
* testsuite/ld-elf/pr25749-2b.s: Likewise.
* testsuite/ld-elf/pr25749.rd: Likewise.
* testsuite/ld-elf/pr25754-1a.c: Likewise.
* testsuite/ld-elf/pr25754-1b.s: Likewise.
* testsuite/ld-elf/pr25754-2a.c: Likewise.
* testsuite/ld-elf/pr25754-2b.err: Likewise.
* testsuite/ld-elf/pr25754-2b.s: Likewise.
* testsuite/ld-elf/pr25754-3a.c: Likewise.
* testsuite/ld-elf/pr25754-3b.s: Likewise.
* testsuite/ld-elf/pr25754-4a.c: Likewise.
* testsuite/ld-elf/pr25754-4b.s: Likewise.
* testsuite/ld-elf/pr25754-4c.s: Likewise.
* testsuite/ld-elf/pr25754-5a.c: Likewise.
* testsuite/ld-elf/pr25754-5b.s: Likewise.
* testsuite/ld-elf/pr25754-5c.s: Likewise.
* testsuite/ld-elf/pr25754-6a.c: Likewise.
* testsuite/ld-elf/pr25754-6b.s: Likewise.
* testsuite/ld-x86-64/pr19609-6a.d: Don't expect linker error.
This patch renames elf_backend_modify_program_headers and moves the
elf.c code tweaking the ELF file header for -pie -Ttext-segment to a
new function, _bfd_elf_modify_headers, which then becomes the default
elf_backed_modify_headers and is called from any other target
elf_backed_modify_headers.
* elf-bfd.h (struct elf_backend_data <elf_backend_modify_headers>):
Rename from elf_backend_modify_program_headers.
(_bfd_elf_modify_headers): Declare.
* elf.c (assign_file_positions_except_relocs): Set
elf_program_header_size. Always call elf_backend_modify_headers.
Extract code modifying file header..
(_bfd_elf_modify_headers): ..to here. New function.
* elf32-arm.c (elf_backend_modify_headers): Renamed from
elf_backend_modify_program_headers.
* elf32-i386.c: Similarly.
* elf64-x86-64.c: Similarly.
* elfxx-target.h: Similarly. Default elf_backend_modify_headers
to _bfd_elf_modify_headers.
* elf-nacl.h (nacl_modify_headers): Rename from
nacl_modify_program_headers.
* elf-nacl.c (nacl_modify_headers): Rename from
nacl_modify_program_headers and call _bfd_elf_modify_headers.
* elf32-rx.c (elf32_rx_modify_headers): Similarly.
* elf32-spu.c (spu_elf_modify_headers): Similarly.
* elfnn-ia64.c (elfNN_ia64_modify_headers): Similarly.
* elf32-sh.c (elf_backend_modify_program_headers): Don't undef.
commit 83924b3846361f2f76f9a6e7b5afa01c0eebbd4f
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Feb 5 18:45:23 2019 -0800
x86-64: Restore PIC check for PCREL reloc against protected symbol
moved PIC check for PC-relative relocations to elf_x86_64_check_relocs.
Since linker defined symbols may not be processed at the time, we need
to move the check back to elf_x86_64_relocate_section.
bfd/
PR ld/24905
* elf64-x86-64.c (elf_x86_64_check_relocs): Move PIC check for
PC-relative relocations back to ...
(elf_x86_64_relocate_section): Here.
ld/
PR ld/24905
* testsuite/ld-x86-64/pr24905-x32.d: New file.
* testsuite/ld-x86-64/pr24905.d: Likewise.
* testsuite/ld-x86-64/pr24905.s: Likewise.
* testsuite/ld-x86-64/pr24905.t: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run pr24905 and pr24905-x32.
Skip symbol defined by linker when checking copy reloc on protected
symbol.
bfd/
PR ld/24276
* elf64-x86-64.c (elf_x86_64_check_relocs): Skip symbol defined
by linker when checking copy reloc on protected symbol.
ld/
PR ld/24276
* testsuite/ld-i386/i386.exp: Run PR ld/24276 test.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr24276.dso: New file.
* testsuite/ld-i386/pr24276.warn: Likewise.
* testsuite/ld-x86-64/pr24276.dso: Likewise.
* testsuite/ld-x86-64/pr24276.warn: Likewise.
commit bd7ab16b4537788ad53521c45469a1bdae84ad4a
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Feb 13 07:34:22 2018 -0800
x86-64: Generate branch with PLT32 relocation
removed check R_X86_64_PC32 relocation against protected symbols in
shared objects. Since elf_x86_64_check_relocs is called after we
have seen all input files, we can check for PC-relative relocations in
elf_x86_64_check_relocs. We should not allow PC-relative relocations
against protected symbols since address of protected function and
location of protected data may not be in the shared object.
bfd/
PR ld/24151
* elf64-x86-64.c (elf_x86_64_need_pic): Check
SYMBOL_DEFINED_NON_SHARED_P instead of def_regular.
(elf_x86_64_relocate_section): Move PIC check for PC-relative
relocations to ...
(elf_x86_64_check_relocs): Here.
(elf_x86_64_finish_dynamic_symbol): Use SYMBOL_DEFINED_NON_SHARED_P
to check if a symbol is defined in a non-shared object.
* elfxx-x86.h (SYMBOL_DEFINED_NON_SHARED_P): New.
ld/
PR ld/24151
* testsuite/ld-x86-64/pr24151a-x32.d: New file.
* testsuite/ld-x86-64/pr24151a.d: Likewise.
* testsuite/ld-x86-64/pr24151a.s: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run pr24151a and pr24151a-x32.
* elf32-i386.c (elf_i386_relocate_section): Call
elf_i386_rtype_to_howto to get reloc_howto_type pointer.
* elf64-x86-64.c (elf_x86_64_relocate_section): Call
elf_x86_64_rtype_to_howto to get reloc_howto_type pointer.
All of the backend relocate_section functions that interpret reloc
numbers assuming the input file is of the expected type (ie. same as
output or very similar) really ought to be checking input file type.
Not many do, and those that do currently just assert. This patch
replaces the assertion with a more graceful exit.
PR 23980
* elf32-i386.c (elf_i386_relocate_section): Exit with wrong format
error rather than asserting input file is as expected.
* elf32-s390.c (elf_s390_relocate_section): Likewise.
* elf32-sh.c (sh_elf_relocate_section): Likewise.
* elf32-xtensa.c (elf_xtensa_relocate_section): Likewise.
* elf64-ppc.c (ppc64_elf_relocate_section): Likewise.
* elf64-s390.c (elf_s390_relocate_section): Likewise.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
* elf32-ppc.c (ppc_elf_relocate_section): Exit with wrong format
error if input file is not ppc32 ELF.
This PR shows a fuzzed binary triggering a segfault via a bad
relocation in .debug_line. It turns out that unlike normal
relocations applied to a section, the linker applies those with
symbols from discarded sections via _bfd_clear_contents without
checking that the relocation is within the section bounds. The same
thing now happens when reading debug sections since commit
a4cd947aca23, the PR23425 fix.
PR 23770
PR 23425
* reloc.c (_bfd_clear_contents): Replace "location" param with
"buf" and "off". Bounds check "off". Return status.
* cofflink.c (_bfd_coff_generic_relocate_section): Update
_bfd_clear_contents call.
* elf-bfd.h (RELOC_AGAINST_DISCARDED_SECTION): Likewise.
* elf32-arc.c (elf_arc_relocate_section): Likewise.
* elf32-i386.c (elf_i386_relocate_section): Likewise.
* elf32-metag.c (metag_final_link_relocate): Likewise.
* elf32-nds32.c (nds32_elf_get_relocated_section_contents): Likewise.
* elf32-ppc.c (ppc_elf_relocate_section): Likewise.
* elf32-visium.c (visium_elf_relocate_section): Likewise.
* elf64-ppc.c (ppc64_elf_relocate_section): Likewise.
* elf64-x86-64.c *(elf_x86_64_relocate_section): Likewise.
* libbfd-in.h (_bfd_clear_contents): Update prototype.
* libbfd.h: Regenerate.
We need to clear the R_X86_64_converted_reloc_bit bit after setting it
to avoid leaking it out by --emit-relocs.
bfd/
PR ld/23324
* elf64-x86-64.c (elf_x86_64_relocate_section): Clear the
R_X86_64_converted_reloc_bit bit.
ld/
PR ld/23324
* testsuite/ld-x86-64/pr23324.s: New file.
* testsuite/ld-x86-64/pr23324a.d: Likewise.
* testsuite/ld-x86-64/pr23324b.d: Likewise.
ENDBR64 is added to the special TLSDESC entry, which is similar to the
PLT0 entry, in the x86-64 lazy procedure linkage table to support Intel
CET. The NaCl PLT is different from the normal PLT. This patch adds
plt_tlsdesc_entry, plt_tlsdesc_entry_size, plt_tlsdesc_got1_offset,
plt_tlsdesc_got2_offset, plt_tlsdesc_got1_insn_end and
plt_tlsdesc_got2_insn_end to elf_x86_lazy_plt_layout to support both
normal and NaCl TLSDESC entries. This fixed
FAIL: TLS descriptor -fpic -shared transitions
for x86_64-nacl.
* elf32-i386.c (elf_i386_lazy_plt): Add plt_tlsdesc_entry,
plt_tlsdesc_entry_size, plt_tlsdesc_got1_offset,
plt_tlsdesc_got2_offset, plt_tlsdesc_got1_insn_end and
plt_tlsdesc_got2_insn_end for TLSDESC entry.
(elf_i386_lazy_ibt_plt): Likewise.
(elf_i386_nacl_plt): Likewise.
* elf64-x86-64.c (tlsdesc_plt_entry): Moved and renamed to ...
(elf_x86_64_tlsdesc_plt_entry): This.
(elf_x86_64_lazy_plt): Add plt_tlsdesc_entry,
plt_tlsdesc_entry_size, plt_tlsdesc_got1_offset,
plt_tlsdesc_got2_offset, plt_tlsdesc_got1_insn_end and
plt_tlsdesc_got2_insn_end for TLSDESC entry.
(elf_x86_64_lazy_bnd_plt): Likewise.
(elf_x86_64_lazy_ibt_plt): Likewise.
(elf_x32_lazy_ibt_plt): Likewise.
(elf_x86_64_nacl_plt): Likewise.
(elf_x86_64_finish_dynamic_sections): Use plt_tlsdesc_entry,
plt_tlsdesc_entry_size, plt_tlsdesc_got1_offset,
plt_tlsdesc_got2_offset, plt_tlsdesc_got1_insn_end and
plt_tlsdesc_got2_insn_end to update TLSDESC entry.
* elfxx-x86.h (elf_x86_lazy_plt_layout): Update comments.
Add plt_tlsdesc_entry, plt_tlsdesc_entry_size,
plt_tlsdesc_got1_offset, plt_tlsdesc_got2_offset,
plt_tlsdesc_got1_insn_end and plt_tlsdesc_got2_insn_end.
(elf_x86_non_lazy_plt_layout): Update comments.
(elf_x86_plt_layout): Likewise.
If IFUNC symbol is defined in position-dependent executable, we should
change it to the normal function and set its address to its PLT entry
which should be resolved by R_*_IRELATIVE at run-time. All external
references should be resolved to its PLT in executable.
bfd/
PR ld/23169
* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Don't issue
an error on IFUNC pointer defined in PDE.
* elf32-i386.c (elf_i386_finish_dynamic_symbol): Call
_bfd_x86_elf_link_fixup_ifunc_symbol.
* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise.
* elfxx-x86.c (_bfd_x86_elf_link_fixup_ifunc_symbol): New
function.
* elfxx-x86.h (_bfd_x86_elf_link_fixup_ifunc_symbol): New.
ld/
PR ld/23169
* testsuite/ld-ifunc/ifunc-9-i386.d: New file.
* testsuite/ld-ifunc/ifunc-9-x86-64.d: Likewise.
* testsuite/ld-ifunc/pr23169a.c: Likewise.
* testsuite/ld-ifunc/pr23169a.rd: Likewise.
* testsuite/ld-ifunc/pr23169b.c: Likewise.
* testsuite/ld-ifunc/pr23169b.c: Likewise.
* testsuite/ld-ifunc/pr23169c.rd: Likewise.
* testsuite/ld-ifunc/pr23169c.rd: Likewise.
* testsuite/ld-ifunc/ifunc-9-x86.d: Removed.
* testsuite/ld-ifunc/ifunc.exp: Run PR ld/23169 tests.
This patch is aimed at silencing gcc8 -Wstringop-truncation warnings.
Unfortunately adding __attribute__ ((__nonstring)) doesn't work in a
number of the places patched here, (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643) so if you have
recent glibc headers installed you'll need to configure binutils with
--disable-werror to compile using gcc8 or gcc9.
include/
* ansidecl.h: Import from gcc.
* coff/internal.h (struct internal_scnhdr): Add ATTRIBUTE_NONSTRING
to s_name.
(struct internal_syment): Add ATTRIBUTE_NONSTRING to _n_name.
bfd/
* elf-linux-core.h (struct elf_external_linux_prpsinfo32_ugid32),
(struct elf_external_linux_prpsinfo32_ugid16),
(struct elf_external_linux_prpsinfo64_ugid32),
(struct elf_external_linux_prpsinfo64_ugid16): Add ATTRIBUTE_NONSTRING
to pr_fname and pr_psargs fields. Remove GCC diagnostic pragmas.
Move comment to..
* elf.c (elfcore_write_prpsinfo): ..here. Indent nested preprocessor
directives.
* elf32-arm.c (elf32_arm_nabi_write_core_note): Add ATTRIBUTE_NONSTRING
to data.
* elf32-ppc.c (ppc_elf_write_core_note): Likewise.
* elf32-s390.c (elf_s390_write_core_note): Likewise.
* elf64-s390.c (elf_s390_write_core_note): Likewise.
* elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
* elf64-x86-64.c (elf_x86_64_write_core_note): Add GCC diagnostic
pragmas.
* peXXigen.c (_bfd_XXi_swap_scnhdr_out): Use strnlen to avoid
false positive gcc-8 warning.
gas/
* config/obj-evax.c (shorten_identifier): Use memcpy in place
of strncpy.
* config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
segname and sectname fields are NUL terminated.
R_X86_64_converted_reloc_bit is set in elf_x86_64_convert_load_reloc
which is called from elf_x86_64_check_relocs. Since it is used only
internally by linker, there is no need to mask it out in
elf_x86_64_info_to_howto.
* elf64-x86-64.c (elf_x86_64_info_to_howto): Don't mask out
R_X86_64_converted_reloc_bit.
The TLSDESC entry in a lazy procedure linkage table is called indirectly
with "callq *(%rax)". This patch adds an ENDBR64 to support indirect
branch tracking in Intel CET. The TLSDESC PLT entry now looks like:
0xf3, 0x0f, 0x1e, 0xfa, /* endbr64 */
0xff, 0x35, 8, 0, 0, 0, /* pushq GOT+8(%rip) */
0xff, 0x25, 16, 0, 0, 0 /* jmpq *GOT+TDG(%rip) */
The BND prefix isn't needed since MPX isn't used for TLSDESC.
bfd/
PR ld/23000
* elf64-x86-64.c (elf_x86_64_finish_dynamic_sections): Add
ENDBR64 to the TLSDESC PLT entry.
ld/
PR ld/23000
* testsuite/ld-x86-64/tlsdesc.pd: Updated.
When resolving a relocation against IFUNC symbol in a SHT_NOTE section
without SHF_ALLOC, we treat it as relocation against FUNC symbol since
it needs the address of IFUNC symbol, not the address returned by IFUNC
function.
bfd/
PR ld/22929
* elf32-i386.c (elf_i386_relocate_section): Treat relocation
against IFUNC symbol in SHT_NOTE section without SHF_ALLOC as
relocation against FUNC symbol.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
ld/
PR ld/22929
* testsuite/ld-i386/i386.exp: Run PR ld/22929 test.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr22929.d: New file.
* testsuite/ld-i386/pr22929.s: Likewise.
* testsuite/ld-x86-64/pr22929.d: Likewise.
* testsuite/ld-x86-64/pr22929.s: Likewise.
This patch adds --enable-separate-code to ld configure to turn on
-z separate-code by default and enables it by default for Linux/x86.
This avoids mixing code pages with data to improve cache performance
as well as security.
To reduce x86-64 executable and shared object sizes, the maximum page
size is reduced from 2MB to 4KB when -z separate-code is turned on by
default. Note: -z max-page-size= can be used to set the maximum page
size.
We compared SPEC CPU 2017 performance before and after this change on
Skylake server. There are no any significant performance changes.
Everything is mostly below +/-1%.
bfd/
* config.in: Regenerated.
* configure: Likewise.
* configure.ac: Add --enable-separate-code.
(DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED. Default
to 1 for Linux/x86 targets,
* elf64-x86-64.c (ELF_MAXPAGESIZE): Set to 0x1000 if
DEFAULT_LD_Z_SEPARATE_CODE is 1.
ld/
* NEWS: Mention --enable-separate-code.
* configure.ac: Add --enable-separate-code.
(DEFAULT_LD_Z_SEPARATE_CODE): New AC_DEFINE_UNQUOTED.
* configure.tgt: Default ac_default_ld_z_separate_code to 1 for
Linux/x86 targets.
* config.in: Regenerated.
* configure: Likewise.
* emultempl/elf32.em (gld${EMULATION_NAME}_before_parse): Set
link_info.separate_code DEFAULT_LD_Z_SEPARATE_CODE.
Since PLT in PDE and PC-relative PLT in PIE can be used as function
address, there is no need for dynamic PC-relative relocation against
a dynamic function definition in PIE. Linker should resolve PC-relative
reference to its PLT address.
NB: i386 has non-PIC PLT and PIC PLT. Only non-PIC PLT in PDE can
be used as function address. PIC PLT in PIE can't be used as
function address.
bfd/
PR ld/22842
* elf32-i386.c (elf_i386_check_relocs): Pass FALSE for non
PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
* elf64-x86-64.c (elf_x86_64_check_relocs): Create PLT for
R_X86_64_PC32 reloc against dynamic function in data section.
Pass TRUE for PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
(elf_x86_64_relocate_section): Use PLT for R_X86_64_PC32 reloc
against dynamic function in data section.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Use PLT in PIE as
function address only if pcrel_plt is true.
(_bfd_x86_elf_link_hash_table_create): Set pcrel_plt.
* elfxx-x86.h (NEED_DYNAMIC_RELOCATION_P): Add PCREL_PLT for
PC-relative PLT. If PLT is PC-relative, don't generate dynamic
PC-relative relocation against a function definition in data
secton in PIE. Remove the obsolete comments.
(elf_x86_link_hash_table): Add pcrel_plt.
ld/
PR ld/22842
* testsuite/ld-i386/i386.exp: Run PR ld/22842 tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr22842a.c: New file.
* testsuite/ld-i386/pr22842b.S: Likewise.
* testsuite/ld-x86-64/pr22842a.c: Likewise.
* testsuite/ld-x86-64/pr22842a.rd: Likewise.
* testsuite/ld-x86-64/pr22842b.S: Likewise.
* testsuite/ld-x86-64/pr22842b.rd: Likewise.
Since there is no need to prepare for PLT branch on x86-64, generate
R_X86_64_PLT32, instead of R_X86_64_PC32, if possible, which can be
used as a marker for 32-bit PC-relative branches.
To compile Linux kernel, this patch:
From: "H.J. Lu" <hjl.tools@gmail.com>
Subject: [PATCH] x86: Treat R_X86_64_PLT32 as R_X86_64_PC32
On i386, there are 2 types of PLTs, PIC and non-PIC. PIE and shared
objects must use PIC PLT. To use PIC PLT, you need to load
_GLOBAL_OFFSET_TABLE_ into EBX first. There is no need for that on
x86-64 since x86-64 uses PC-relative PLT.
On x86-64, for 32-bit PC-relative branches, we can generate PLT32
relocation, instead of PC32 relocation, which can also be used as
a marker for 32-bit PC-relative branches. Linker can always reduce
PLT32 relocation to PC32 if function is defined locally. Local
functions should use PC32 relocation. As far as Linux kernel is
concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32
since Linux kernel doesn't use PLT.
is needed. It is available on hjl/plt32/master branch at
https://github.com/hjl-tools/linux
bfd/
PR gas/22791
* elf64-x86-64.c (is_32bit_relative_branch): Removed.
(elf_x86_64_relocate_section): Check PIC relocations in PIE.
Remove is_32bit_relative_branch usage. Disallow PC32 reloc
against protected function in shared object.
gas/
PR gas/22791
* config/tc-i386.c (need_plt32_p): New function.
(output_jump): Generate BFD_RELOC_X86_64_PLT32 if possible.
(md_estimate_size_before_relax): Likewise.
* testsuite/gas/i386/reloc64.d: Updated.
* testsuite/gas/i386/x86-64-jump.d: Likewise.
* testsuite/gas/i386/x86-64-mpx-branch-1.d: Likewise.
* testsuite/gas/i386/x86-64-mpx-branch-2.d: Likewise.
* testsuite/gas/i386/x86-64-relax-2.d: Likewise.
* testsuite/gas/i386/x86-64-relax-3.d: Likewise.
* testsuite/gas/i386/ilp32/reloc64.d: Likewise.
* testsuite/gas/i386/ilp32/x86-64-branch.d: Likewise.
ld/
PR gas/22791
* testsuite/ld-x86-64/mpx1c.rd: Updated.
* testsuite/ld-x86-64/pr22791-1.err: New file.
* testsuite/ld-x86-64/pr22791-1a.c: Likewise.
* testsuite/ld-x86-64/pr22791-1b.s: Likewise.
* testsuite/ld-x86-64/pr22791-2.rd: Likewise.
* testsuite/ld-x86-64/pr22791-2a.s: Likewise.
* testsuite/ld-x86-64/pr22791-2b.c: Likewise.
* testsuite/ld-x86-64/pr22791-2c.s: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run PR ld/22791 tests.
Solaris requires to keep _GLOBAL_OFFSET_TABLE_ even if it isn't used.
This patch detects Solaris target and keeps _GLOBAL_OFFSET_TABLE_ for
Solaris.
* elf32-i386.c (elf32_i386_copy_solaris_special_section_fields):
New prototype.
(elf_i386_link_setup_gnu_properties): Set need_global_offset_table
for Solaris.
* elf64-x86-64.c (elf64_x86_64_copy_solaris_special_section_fields):
New prototype.
(elf_x86_64_link_setup_gnu_properties): Set
need_global_offset_table for Solaris.
* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Keep the
unused _GLOBAL_OFFSET_TABLE_ for Solaris.
(_bfd_x86_elf_link_setup_gnu_properties): Copy
need_global_offset_table.
* elfxx-x86.h (elf_x86_link_hash_table): Add
need_global_offset_table.
(elf_x86_init_table): Likewise.
Since _GLOBAL_OFFSET_TABLE_ may be referenced implicitly on x86,
checking ref_regular_nonweak leaves the unused _GLOBAL_OFFSET_TABLE_
in output. This patch checks explicit GOT references instead.
ld-i386/discarded1.s and ld-x86-64/discarded1.s are updated to avoid
linker optimization which removes GOT references.
bfd/
PR ld/22782
* elf32-i386.c (elf_i386_check_relocs): Set got_referenced if
_GLOBAL_OFFSET_TABLE_ is referenced or GOT is needed to resolve
undefined weak symbol to 0.
* elf64-x86-64.c (elf_x86_64_check_relocs): Set got_referenced
if _GLOBAL_OFFSET_TABLE_ is referenced.
* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Check
got_referenced instead of ref_regular_nonweak. Remove the
unused _GLOBAL_OFFSET_TABLE_ from symbol table.
* elfxx-x86.h (elf_x86_link_hash_table): Add got_referenced.
ld/
PR ld/22782
* testsuite/ld-i386/discarded1.s: Replace mov with div.
* testsuite/ld-x86-64/discarded1.s: Likewise.
* testsuite/ld-i386/i386.exp: Run pr22782.
* testsuite/ld-i386/load1-nacl.d: Updated for removing
_GLOBAL_OFFSET_TABLE_ from output.
* testsuite/ld-i386/load1.d: Likewise.
* testsuite/ld-x86-64/load1a-nacl.d: Likewise.
* testsuite/ld-x86-64/load1a.d: Likewise.
* testsuite/ld-x86-64/load1b-nacl.d: Likewise.
* testsuite/ld-x86-64/load1b.d: Likewise.
* testsuite/ld-i386/pr22782.d: New file.
* testsuite/ld-i386/pr22782.s: Likewise.
* testsuite/ld-x86-64/pr22782.s: Likewise.
* testsuite/ld-x86-64/pr22782a.d: Likewise.
* testsuite/ld-x86-64/pr22782b.d: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run pr22782a and pr22782b.
H.J. Lu
Alan Modra
Nick Clifton