binutils-gdb/bfd/ChangeLog
H.J. Lu 0ff2b86e7c Create the second PLT for BND relocations
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.
2014-02-19 11:48:23 -08:00

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2014-02-19 Igor Zamyatin <igor.zamyatin@intel.com>
H.J. Lu <hongjiu.lu@intel.com>
* 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.
2014-02-19 Alan Modra <amodra@gmail.com>
* elf64-ppc.h (struct ppc64_elf_params): Add save_restore_funcs.
* elf64-ppc.c (ppc64_elf_func_desc_adjust): Use it to control
provision of out-of-line register save/restore routines.
2014-02-18 Jack Carter <jack.carter@imgtec.com>
* elfxx-mips.c(_bfd_mips_elf_modify_segment_map): Deleted hard coding of
PT_DYNAMIC segment flags.
2014-02-17 Jan Kratochvil <jan.kratochvil@redhat.com>
PR binutils/16595
* simple.c (struct saved_offsets): New.
(simple_save_output_info): Use it for ptr.
(simple_restore_output_info): Use it for ptr. Check section_count.
(bfd_simple_get_relocated_section_contents): Use it for saved_offsets.
2014-02-17 Alan Modra <amodra@gmail.com>
* elf64-ppc.h (struct ppc64_elf_params): Define.
(ppc64_elf_init_stub_bfd, ppc64_elf_edit_opd, ppc64_elf_tls_setup,
ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
ppc64_elf_build_stubs): Update prototype.
* elf64-ppp.c (struct ppc_link_hash_table): Add params, delete other
fields now in params. Adjust code throughout file.
(ppc64_elf_init_stub_bfd): Delete "abfd" parameter, add "params".
Save params pointer in htab.
(ppc64_elf_edit_opd, ppc64_elf_tls_setup,
ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
ppc64_elf_build_stubs): Remove parameters now in "params".
2014-02-17 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (ppc_elf_relocate_section): Move relocs on insns
patched for ppc476 workaround. Reapply branch taken/not taken
relocs.
2014-02-12 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (ppc_elf_relax_section): Don't build long-branch
stubs for calls to __tls_get_addr that we know will later be
optimised away.
2014-02-12 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (ppc_elf_relax_section): Enable ppc476 workaround
for ld -r, when code sections are sufficiently aligned.
* elf32-ppc.h (struct ppc_elf_params): Delete pagesize. Add
pagesize_p2.
2014-02-12 Alan Modra <amodra@gmail.com>
PR gold/15530
* elf64-ppc.c (ppc64_elf_gc_mark_dynamic_ref): Support
--export-dynamic and --dynamic-list marking of symbols.
* elflink.c (bfd_elf_gc_mark_dynamic_ref_symbol): Reorder
cheap tests first.
2014-02-10 H.J. Lu <hongjiu.lu@intel.com>
PR gold/16530
* elflink.c (bfd_elf_gc_mark_dynamic_ref_symbol): Mark symbol in
executables if it matches dynamic_list.
2014-02-10 Alan Modra <amodra@gmail.com>
* po/SRC-POTFILES.in: Regenerate.
* po/bfd.pot: Regenerate.
2014-02-09 Alan Modra <amodra@gmail.com>
* elf-bfd.h (struct elf_backend_data): Add caches_rawsize.
* elfxx-target.h (elf_backend_caches_rawsize): Define.
(elfNN_bed): Init new field.
* elflink.c (elf_link_input_bfd): Handle caches_rawsize.
* elf32-ppc.c (shared_stub_entry): Zero addi offset.
(ppc_elf_relax_section): Don't reallocate section here, write
stubs, or write out relocs for ld -r here..
(ppc_elf_relocate_section): ..instead write stubs here, and use
existing code to write out relocs for ld -r. Fix offset
adjustment on reloc for little-endian.
(elf_backend_caches_rawsize): Define.
2014-02-07 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
PR build/16550
* cache.c (bfd_cache_max_open): Cast RLIM_INFINITY to rlim_t.
2014-02-04 Jan Kratochvil <jan.kratochvil@redhat.com>
* coff-rs6000.c (xcoff_write_archive_contents_big): Free OFFSETS in
return paths. Three times.
* elf64-ppc.c (ppc64_elf_link_hash_table_create): Free HTAB in all
return paths.
(ppc64_elf_tls_optimize): Free TOC_REF in return path.
(ppc64_elf_edit_toc): Free USED in return path.
2014-02-03 Sandra Loosemore <sandra@codesourcery.com>
* reloc.c (BFD_RELOC_NIOS2_GOT_LO, BFD_RELOC_NIOS2_GOT_HA): New.
(BFD_RELOC_NIOS2_CALL_LO, BFD_RELOC_NIOS2_CALL_HA): New.
* libbfd.h: Regenerated.
* bfd-in2.h: Regenerated.
* elf32-nios2.c (elf_nios2_howto_table_rel): Add new relocations.
(nios2_reloc_map): Likewise.
(GOT_USED, CALL_USED): Renamed from GOT16_USED and CALL16_USED.
Fixed all references.
(nios2_elf32_relocate_section): Add new relocations.
(nios2_elf32_check_relocs): Likewise.
(nios2_elf32_gc_sweep_hook): Likewise.
2014-02-03 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (struct ppc_elf_link_hash_table): Add params.
Delete emit_stub_syms, no_tls_get_addr_opt. Update all uses.
(ppc_elf_link_params): New function.
(ppc_elf_create_glink): Align .glink to 64 bytes for ppc476
workaround.
(ppc_elf_select_plt_layout): Remove plt_style and emit_stub_syms
parameters. Use htab->params instead.
(ppc_elf_tls_setup): Remove no_tls_get_addr_opt parameter.
(ppc_elf_size_dynamic_sections): Align __glink_PLTresolve to
64 bytes for ppc476 workaround.
(struct ppc_elf_relax_info): New.
(ppc_elf_relax_section): Exclude linker created sections and
those too small to hold one instruction. Don't add another
branch around trampolines on later relax passes. Don't
generate trampolines for undefined symbols when !relocatable,
nor for plugin symbols. Allocate space for ppc476 workaround
patch area. Free fixups on error return path.
(ppc_elf_relocate_section): Handle ppc476 workaround patching.
* elf32-ppc.h (struct ppc_elf_params): New.
(ppc_elf_select_plt_layout, ppc_elf_tls_setup): Update prototype.
(ppc_elf_link_params): Declare.
* section.c (SEC_INFO_TYPE_TARGET): Define.
* bfd-in2.h: Regenerate.
2014-02-02 Sandra Loosemore <sandra@codesourcery.com>
* elf32-nios2.c (struct elf32_nios2_link_hash_table): Add
h_gp_got field.
(nios2_elf32_relocate_section): Use got_base to adjust
GOT-pointer-relative relocations relative to _gp_got.
(create_got_section): Create _gp_got symbol.
(nios2_elf32_finish_dynamic_symbol): Make _gp_got absolute.
(nios2_elf32_size_dynamic_sections): Set _gp_got offset.
2014-01-30 Sandra Loosemore <sandra@codesourcery.com>
* bfd-in2.h: Update from reloc.c.
* elf32-nios2.c: Include elf32-nios2.h.
(elf_nios2_howto_table_rel): Add entry for R_NIOS2_CALL26_NOAT.
(nios2_reloc_map): Likewise.
(enum elf32_nios2_stub_type): Declare.
(struct elf32_nios2_stub_hash_entry): Declare.
(nios2_stub_hash_entry, nios2_stub_hash_lookup): New macros.
(struct elf32_nios2_link_hash_entry): Add hsh_cache field.
(struct elf32_nios2_link_hash_table): Add new fields bstab,
stub_bfd, add_stub_section, layout_sections_again, stub_group,
bfd_count, top_index, input_list, all_local_syms.
(nios2_call26_stub_entry): New.
(nios2_elf32_install_imm16): Move up in file.
(nios2_elf32_install_data): Move up in file.
(hiadj): Move up in file.
(stub_hash_newfunc): New.
(link_hash_newfunc): Initialize hsh_cache field.
(STUB_SUFFIX): New.
(nios2_stub_name): New.
(nios2_get_stub_entry): New.
(nios2_add_stub): New.
(nios2_elf32_setup_section_lists): New.
(nios2_elf32_next_input_section): New.
(CALL26_SEGMENT): New.
(MAX_STUB_SECTION_SIZE): New.
(group_sections): New.
(nios2_type_of_stub): New.
(nios2_build_one_stub): New.
(nios2_size_one_stub): New.
(get_local_syms): New.
(nios2_elf32_size_stubs): New.
(nios2_elf32_build_stubs): New.
(nios2_elf32_do_call26_relocate): Correct CALL26 overflow test.
(nios2_elf32_relocate_section): Handle R_NIOS2_CALL26_NOAT. Add
trampolines for R_NIOS2_CALL26 stubs.
(nios2_elf32_check_relocs): Handle R_NIOS2_CALL26_NOAT.
(nios2_elf32_gc_sweep_hook): Likewise.
(nios2_elf32_link_hash_table_create): Initialize the stub hash table.
(nios2_elf32_link_hash_table_free): New.
(bfd_elf32_bfd_link_hash_table_free): Define.
* elf32-nios2.h: New file.
* libbfd.h: Update from reloc.c.
* reloc.c (BFD_RELOC_NIOS2_CALL26_NOAT): New.
2014-01-29 Nick Clifton <nickc@redhat.com>
PR binutils/16318
* elf32-metag.c (elf_metag_post_process_headers): Call
_bfd_elf_post_process_headers.
* elf32-sh64.c (sh64_elf_copy_private_data): Call
_bfd_elf_copy_private_data.
* elf64-sh64.c (sh_elf64_copy_private_data_internal): Likewise.
2014-01-29 Nick Clifton <nickc@redhat.com>
* bfd-in.h (bfd_set_section_vma): Delete.
(bfd_set_section_alignment): Delete.
(bfd_set_section_userdata): Delete.
(bfd_set_cacheable): Delete.
* bfd.c (bfd_set_cacheable): New static inline function.
* section.c (bfd_set_section_userdata): Likewise.
(bfd_set_section_vma): Likewise.
(bfd_set_section_alignment): Likewise.
* bfd-in2.h: Regenerate.
2014-01-28 Nick Clifton <nickc@redhat.com>
* dwarf2.c (find_abstract_instance_name): For DW_FORM_ref_addr
attributes select the CU containing the abbreviation, which may not
be the current CU.
2014-01-24 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (ppc_build_one_stub): Correct reloc count passed
to get_relocs for ELFv2.
2014-01-23 H.J. Lu <hongjiu.lu@intel.com>
PR ld/16498
* elf.c (_bfd_elf_map_sections_to_segments): Issue a linker error
if TLS sections are not adjacent.
2014-01-22 Alan Modra <amodra@gmail.com>
* elflink.c (elf_link_add_object_symbols): Call minfo for --as-needed.
2014-01-22 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (STK_LINKER): Comment typo fix.
2014-01-21 H.J. Lu <hongjiu.lu@intel.com>
PR ld/16467
* elflink.c (_bfd_elf_merge_symbol): When types of the existing
regular default symbol definition and the versioned dynamic
symbol definition mismatch, skip the default symbol definition
if one of them is IFUNC.
2014-01-21 H.J. Lu <hongjiu.lu@intel.com>
PR ld/2404
* elflink.c (_bfd_elf_merge_symbol): Don't check info->shared,
info->export_dynamic nor h->ref_dynamic for type mismatch when
adding the default version.
2014-01-16 Alan Modra <amodra@gmail.com>
* elfxx-mips.c (mips_elf_record_got_page_entry): Pass in a
mips_elf_traverse_got_arg* rather than mips_got_info*.
Adjust caller. Alloc on output_bfd rather than symbol section
owner.
2014-01-15 H.J. Lu <hongjiu.lu@intel.com>
* elf32-i386.c (elf_i386_allocate_dynrelocs): Revert the last
change.
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Likewise.
2014-01-14 H.J. Lu <hongjiu.lu@intel.com>
PR ld/16428
* elf32-i386.c (elf_i386_allocate_dynrelocs): Don't discard relocs
against __ehdr_start.
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Likewise.
2014-01-14 H.J. Lu <hongjiu.lu@intel.com>
* elf32-i386.c (elf_i386_allocate_dynrelocs): Revert the last
change.
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Likewise.
2014-01-14 H.J. Lu <hongjiu.lu@intel.com>
PR ld/16428
* elf32-i386.c (elf_i386_allocate_dynrelocs): Don't update reloc
count if there are any non pc-relative relocs.
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Likewise.
2014-01-14 Michael Hudson-Doyle <michael.hudson@linaro.org>
Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org>
* elfnn-aarch64.c (elfNN_aarch64_final_link_relocate): Use correct
offset while calculating relocation address.
(elfNN_aarch64_create_small_pltn_entry): Likewise.
(elfNN_aarch64_init_small_plt0_entry): Likewise.
2014-01-13 Ma Jiang <ma.jiang@zte.com.cn>
PR ld/16202
* elf32-arm.c (elf32_arm_final_link_relocate): Refetch addends for
R_ARM_ABS8 and R_ARM_ABS16.
2014-01-13 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (ppc_elf_check_relocs): For @local call to ifunc,
error when shared and force a plt call otherwise.
(ppc_elf_size_dynamic_sections): Don't emit DT_PPC_GOT unless
plt_type == PLT_NEW.
(ppc_elf_relocate_section): Add missing test to resolve ifuncs to
the appropriate call stub.
2014-01-10 Alan Modra <amodra@gmail.com>
PR ld/14207
PR ld/16322
PR binutils/16323
* elf.c (assign_file_positions_for_load_sections): Revert last change.
(assign_file_positions_for_non_load_sections): When setting up
PT_GNU_RELRO header, don't require a corresponding PT_LOAD
header that completely covers the relro region.
2014-01-09 Tristan Gingold <gingold@adacore.com>
* coff-rs6000.c (rs6000coff_vec, pmac_xcoff_vec): use jump
table macros and add macros to initializa the structure.
2014-01-08 H.J. Lu <hongjiu.lu@intel.com>
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.
2014-01-07 Tom Tromey <tromey@redhat.com>
* elf32-xtensa.c (vsprint_msg): Don't use old VA_* compatibility
wrappers.
2014-01-03 Nick Clifton <nickc@redhat.com>
PR binutils/16199
* elf.c (vma_page_aligned_bias): Handle a maxpagesize value of
zero.
2014-01-02 Yuanhui Zhang <asmwarrior@gmail.com>
PR binutils/14289
* pef.c (bfd_pef_xlib_read_header): Increase buffer size to 80.
2014-01-02 Nick Clifton <nickc@redhat.com>
PR binutils/11983
* archive.c (_bfd_get_elt_at_filepos): Store a copy of the
filename in the bfd's filename field.
* elfcode.h (bfd_from_remote_memory): Likewise.
* ieee.c (ieee_object_p): Likewise.
* mach-o.c (bfd_mach_o_fat_member_init): Likewise.
* oasys.c (oasys_openr_next_archived_file): Likewise.
* vms-lib.c (_bfd_vms_lib_get_module): Likewise.
* opncls.c (bfd_fopen): Likewise.
(bfd_openstreamr): Likewise.
(bfd_openr_iovec): Likewise.
(bfd_openw): Likewise.
(bfd_create): Likewise.
(_bfd_delete_bfd): Free filename.
For older changes see ChangeLog-2013
Copyright (C) 2014 Free Software Foundation, Inc.
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