Structions with R_X86_64_GOTTPOFF relocation must be encoded with REX
prefix even if it isn't required by destination register. Otherwise
linker can't safely perform IE -> LE optimization.
bfd/
PR ld/17482
* elf64-x86-64.c (elf_x86_64_relocate_section): Update comments
for IE->LE transition.
gas/
PR ld/17482
* config/tc-i386.c (output_insn): Add a dummy REX_OPCODE prefix
for structions with R_X86_64_GOTTPOFF relocation for x32 if needed.
gas/testsuite/
PR ld/17482
* gas/i386/ilp32/x32-tls.d: New file.
* gas/i386/ilp32/x32-tls.s: Likewise.
ld/testsuite/
PR ld/17482
* ld-x86-64/tlsie4.dd: Updated.
Relocations against .got.plt section may not be in the same order as
entries in PLT section. It is incorrect to assume that the Ith reloction
index against .got.plt section always maps to the (I + 1)th entry in PLT
section. This patch matches the .got.plt relocation offset/index in PLT
entry against the index in .got.plt relocation table. It only checks
R_*_JUMP_SLOT and R_*_IRELATIVE relocations. It ignores R_*_TLS_DESC
and R_*_TLSDESC relocations since they have different PLT entries.
bfd/
PR binutils/17154
* elf32-i386.c (elf_i386_plt_sym_val): Only match R_*_JUMP_SLOT
and R_*_IRELATIVE relocation offset with PLT entry.
* elf64-x86-64.c (elf_x86_64_plt_sym_val): Likewise.
(elf_x86_64_plt_sym_val_offset_plt_bnd): New.
(elf_x86_64_get_synthetic_symtab): Use it.
ld/testsuite/
PR binutils/17154
* ld-ifunc/pr17154-i386.d: New file.
* ld-ifunc/pr17154-x86-64.d: Likewise.
* ld-ifunc/pr17154-x86.s: Likewise.
* ld-x86-64/bnd-ifunc-2.d: Likewise.
* ld-x86-64/bnd-ifunc-2.s: Likewise.
* ld-x86-64/mpx.exp: Run bnd-ifunc-2.
* ld-x86-64/tlsdesc-nacl.pd: Updated.
* ld-x86-64/tlsdesc.pd: Likewise.
Intel MPX introduces 4 bound registers, which will be used for parameter
passing in x86-64. Bound registers are cleared by branch instructions.
Branch instructions with BND prefix will keep bound register contents.
This leads to 2 requirements to 64-bit MPX run-time:
1. Dynamic linker (ld.so) should save and restore bound registers during
symbol lookup.
2. Change the current 16-byte PLT0:
ff 35 08 00 00 00 pushq GOT+8(%rip)
ff 25 00 10 00 jmpq *GOT+16(%rip)
0f 1f 40 00 nopl 0x0(%rax)
and 16-byte PLT1:
ff 25 00 00 00 00 jmpq *name@GOTPCREL(%rip)
68 00 00 00 00 pushq $index
e9 00 00 00 00 jmpq PLT0
which clear bound registers, to preserve bound registers.
We use 2 new relocations:
to mark branch instructions with BND prefix.
When linker sees any R_X86_64_PC32_BND or R_X86_64_PLT32_BND relocations,
it switches to a different PLT0:
ff 35 08 00 00 00 pushq GOT+8(%rip)
f2 ff 25 00 10 00 bnd jmpq *GOT+16(%rip)
0f 1f 00 nopl (%rax)
to preserve bound registers for symbol lookup and it also creates an
external PLT section, .pl.bnd. Linker will create a BND PLT1 entry
in .plt:
68 00 00 00 00 pushq $index
f2 e9 00 00 00 00 bnd jmpq PLT0
0f 1f 44 00 00 nopl 0(%rax,%rax,1)
and a 8-byte BND PLT entry in .plt.bnd:
f2 ff 25 00 00 00 00 bnd jmpq *name@GOTPCREL(%rip)
90 nop
Otherwise, linker will create a legacy PLT1 entry in .plt:
68 00 00 00 00 pushq $index
e9 00 00 00 00 jmpq PLT0
66 0f 1f 44 00 00 nopw 0(%rax,%rax,1)
and a 8-byte legacy PLT in .plt.bnd:
ff 25 00 00 00 00 jmpq *name@GOTPCREL(%rip)
66 90 xchg %ax,%ax
The initial value of the GOT entry for "name" will be set to the the
"pushq" instruction in the corresponding entry in .plt. Linker will
resolve reference of symbol "name" to the entry in the second PLT,
.plt.bnd.
Prelink stores the offset of pushq of PLT1 (plt_base + 0x10) in GOT[1]
and GOT[1] is stored in GOT[3]. We can undo prelink in GOT by computing
the corresponding the pushq offset with
GOT[1] + (GOT offset - &GOT[3]) * 2
Since for each entry in .plt except for PLT0 we create a 8-byte entry in
.plt.bnd, there is extra 8-byte per PLT symbol.
We also investigated the 16-byte entry for .plt.bnd. We compared the
8-byte entry vs the the 16-byte entry for .plt.bnd on Sandy Bridge.
There are no performance differences in SPEC CPU 2000/2006 as well as
micro benchmarks.
Pros:
No change to undo prelink in dynamic linker.
Only 8-byte memory overhead for each PLT symbol.
Cons:
Extra .plt.bnd section is needed.
Extra 8 byte for legacy branches to PLT.
GDB is unware of the new layout of .plt and .plt.bnd.
bfd/
* elf64-x86-64.c (elf_x86_64_bnd_plt0_entry): New.
(elf_x86_64_legacy_plt_entry): Likewise.
(elf_x86_64_bnd_plt_entry): Likewise.
(elf_x86_64_legacy_plt2_entry): Likewise.
(elf_x86_64_bnd_plt2_entry): Likewise.
(elf_x86_64_bnd_arch_bed): Likewise.
(elf_x86_64_link_hash_entry): Add has_bnd_reloc and plt_bnd.
(elf_x86_64_link_hash_table): Add plt_bnd.
(elf_x86_64_link_hash_newfunc): Initialize has_bnd_reloc and
plt_bnd.
(elf_x86_64_copy_indirect_symbol): Also copy has_bnd_reloc.
(elf_x86_64_check_relocs): Create the second PLT for Intel MPX
in 64-bit mode.
(elf_x86_64_allocate_dynrelocs): Handle the second PLT for IFUNC
symbols. Resolve call to the second PLT if it is created.
(elf_x86_64_size_dynamic_sections): Keep the second PLT section.
(elf_x86_64_relocate_section): Resolve PLT references to the
second PLT if it is created.
(elf_x86_64_finish_dynamic_symbol): Use BND PLT0 and fill the
second PLT entry for BND relocation.
(elf_x86_64_finish_dynamic_sections): Use MPX backend data if
the second PLT is created.
(elf_x86_64_get_synthetic_symtab): New.
(bfd_elf64_get_synthetic_symtab): Likewise. Undefine for NaCl.
ld/
* emulparams/elf_x86_64.sh (TINY_READONLY_SECTION): New.
ld/testsuite/
* ld-x86-64/mpx.exp: Run bnd-ifunc-1 and bnd-plt-1.
* ld-x86-64/bnd-ifunc-1.d: New file.
* ld-x86-64/bnd-ifunc-1.s: Likewise.
* ld-x86-64/bnd-plt-1.d: Likewise.
This patch fixes 2 GNU_RELRO segment bugs:
1. lang_size_sections didn't properly align base to the maximum
alignment power of sections between DATA_SEGMENT_ALIGN and
DATA_SEGMENT_RELRO_END.
2. ld failed to adjust LOAD segment to generate GNU_RELRO segment
when LOAD segment doesn't fit GNU_RELRO segment. This is
https://sourceware.org/bugzilla/show_bug.cgi?id=14207
We "fixed" ld by not generating GNU_RELRO segment. This patch
adjusts LOAD segment to generate GNU_RELRO segment. It fixes
PR ld/16322 and at the same time it also fixes PR binutils/16323
since now we can adjust LOAD segment if it is too small.
bfd/
PR ld/14207
PR ld/16322
PR binutils/16323
* elf.c (_bfd_elf_map_sections_to_segments): Don't check section
size for PT_GNU_RELRO segment.
(assign_file_positions_for_load_sections): If PT_LOAD segment
doesn't fit PT_GNU_RELRO segment, adjust its p_filesz and p_memsz.
ld/
PR ld/14207
PR ld/16322
PR binutils/16323
* ldlang.c (lang_size_sections): Properly align RELRO base.
ld/testsuite/
PR ld/14207
PR ld/16322
PR binutils/16323
* ld-elf/pr16322.d: New file.
* ld-elf/pr16322.s: Likewise.
* ld-x86-64/pr14207.d: Expect PT_GNU_RELRO segment.
bfd/
* archures.c (bfd_mach_i386_nacl): Fix definition so it doesn't
collide with bfd_mach_l1om.
* bfd-in2.h: Regenerate.
* elf32-i386.c (elf32_i386_nacl_elf_object_p): New function.
(elf_backend_object_p): Use that in elf32-i386-nacl definition.
* elf64-x86-64.c (elf64_x86_64_nacl_elf_object_p): New function.
(elf_backend_object_p): Use that in elf64-x86-64-nacl definition.
(elf32_x86_64_nacl_elf_object_p): New function.
(elf_backend_object_p): Use that in elf32-x86-64-nacl definition.
binutils/
* objdump.c (dump_dwarf): Grok bfd_mach_x86_64_nacl and
bfd_mach_x64_32_nacl as equivalent to bfd_mach_x86_64.
ld/testsuite/
* ld-x86-64/x86-64.exp (mixed1, mixed2): Loosen error string match
so it accepts "i386:nacl" in place of "i386".
* ld-x86-64/ilp32-2.d: Likewise.
* ld-x86-64/ilp32-3.d: Likewise.
* ld-x86-64/lp64-2.d: Likewise.
* ld-x86-64/lp64-3.d: Likewise.
* archures.c (bfd_mach_i386_nacl, bfd_mach_i386_i386_nacl): New macros.
(bfd_mach_x86_64_nacl, bfd_mach_x64_32_nacl): New macros.
* cpu-i386.c (bfd_arch_i386_onebyte_nop_fill): New function.
(bfd_i386_nacl_arch): New variable.
(bfd_x86_64_nacl_arch, bfd_x64_32_nacl_arch): New variables.
(bfd_x64_32_arch_intel_syntax): Link them into the list.
* bfd-in2.h: Regenerate.
ld/
* emulparams/elf_i386_nacl.sh (ARCH): Set to i386:nacl.
* emulparams/elf_x86_64_nacl.sh (ARCH): Set to i386:x86-64:nacl.
* emulparams/elf32_x86_64_nacl.sh (ARCH): Set to i386:x64-32:nacl.
ld/testsuite/
* ld-x86-64/x86-64.exp (Mixed x86_64 and i386 input test 1):
Loosen string match to admit i386:x86-64*.
(Mixed x86_64 and i386 input test 2): Likewise.
* ld-x86-64/ilp32-2.d: Likewise.
* ld-x86-64/ilp32-3.d: Likewise.
* ld-x86-64/lp64-2.d: Likewise.
* ld-x86-64/lp64-3.d: Likewise.
* ld-x86-64/ia32-2.d: Likewise, and i386.* too.
* ld-x86-64/ia32-3.d: Likewise.
* elf-nacl.c (nacl_modify_segment_map): Fix logic reordering the
elf_segment_map list. If an executable segment is page-aligned
but does not end with a full page, then append a fake section into
the segment map entry that pads out the page.
(nacl_final_write_processing): New function. Write the code fill
laid out in nacl_modify_segment_map.
* elf-nacl.h: Declare it.
* elf32-arm.c (elf32_arm_nacl_final_write_processing): New function.
(elf_backend_final_write_processing): Define it for NaCl backend.
* elf32-i386.c (elf_backend_final_write_processing): Likewise.
* elf64-x86-64.c (elf_backend_final_write_processing): Likewise.
* elf-nacl.c (segment_eligible_for_headers): Rename MAXPAGESIZE
parameter to MINPAGESIZE.
(nacl_modify_segment_map): Use minpagesize instead of maxpagesize.
* elf32-arm.c (ELF_MINPAGESIZE, ELF_COMMONPAGESIZE): Set to
0x10000 for NaCl targets.
ld/testsuite/
* ld-x86-64/ilp32-4-nacl.d: Loosen .shstrtab line regexp to match
any file offset.
* ld-x86-64/tlsbin-nacl.rd: Update expected code segment PT_LOAD.
* ld-x86-64/tlsbindesc-nacl.rd: Likewise.
* ld-scripts/rgn-at3.d: XFAIL for *-*-nacl* targets.
* ld-scripts/rgn-over8-ok.d: Likewise.
* ld-elf/export-class.vd: New test.
* ld-elf/export-class-def.s: New test source.
* ld-elf/export-class-dep.s: New test source.
* ld-elf/export-class-lib.s: New test source.
* ld-elf/export-class-ref.s: New test source.
* ld-elf/export-class-lib.ver: New test version script.
* ld-elf/export-class.exp: New test script.
* ld-arm/arm-export-class.rd: New test.
* ld-arm/arm-export-class.xd: New test.
* ld-arm/export-class.exp: New test script.
* ld-i386/i386-export-class.rd: New test.
* ld-i386/i386-export-class.xd: New test.
* ld-i386/export-class.exp: New test script.
* ld-mips-elf/mips-32-export-class.rd: New test.
* ld-mips-elf/mips-32-export-class.xd: New test.
* ld-mips-elf/mips-64-export-class.rd: New test.
* ld-mips-elf/mips-64-export-class.xd: New test.
* ld-mips-elf/export-class.exp: New test script.
* ld-powerpc/powerpc-32-export-class.rd: New test.
* ld-powerpc/powerpc-32-export-class.xd: New test.
* ld-powerpc/powerpc-64-export-class.rd: New test.
* ld-powerpc/powerpc-64-export-class.xd: New test.
* ld-powerpc/export-class.exp: New test script.
* ld-x86-64/x86-64-64-export-class.rd: New test.
* ld-x86-64/x86-64-x32-export-class.rd: New test.
* ld-x86-64/export-class.exp: New test script.
* elflink.c (elf_link_input_bfd): Provide a file symbol for
each input file with local syms, if the input lacks such.
(bfd_elf_final_link): Add a file symbol to mark end of locals
for which we can associate with input files.
(struct elf_final_link_info): Add filesym_count field.
(struct elf_outext_info): Add need_second_pass and second_pass.
(elf_link_output_extsym): Detect symbols defined in the output
file, emit them on second pass over locals.
ld/testsuite/
Update to suit added STT_FILE symbols.
* ld-x86-64/pr12570a.d (name): Distinguish it from pr12570b.d case.
Loosen CFI-matching regexp so it matches x86_64-*-nacl* variant too.
* ld-x86-64/pr12570b.d: Likewise.
* ld-x86-64/x86-64.exp: Revert last change.
bfd/
* elf64-x86-64.c (elf_x86_64_relocate_section): Display signed
hex number in x32 addend overflow check.
gas/
* config/tc-i386.c (tc_gen_reloc): Display signed hex number in
x32 addend overflow check.
ld/testsuite/
* ld-x86-64/ilp32-11.d: Updated.
