Add VERIFY_COPY_RELOC to verify that symbol supports copy relocation.
* elfxx-x86.h (VERIFY_COPY_RELOC): New.
* elf32-i386.c (elf_i386_finish_dynamic_symbol): Use it.
* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise.
Add VERIFY_PLT_ENTRY to verify that symbol has an entry in the procedure
linkage table.
* elfxx-x86.h (VERIFY_PLT_ENTRY): New.
* elf32-i386.c (elf_i386_finish_dynamic_symbol): Use it.
* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise.
Add COPY_INPUT_RELOC_P which returns TRUE if input relocation should
be copied to output.
* elfxx-x86.h (COPY_INPUT_RELOC_P): New.
* elf32-i386.c (elf_i386_relocate_section): Use it.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
Add GENERATE_DYNAMIC_RELOCATION_P which returns TRUE if dynamic
relocation should be generated.
* elf32-i386.c (X86_SIZE_TYPE_P): New.
(elf_i386_relocate_section): Use GENERATE_DYNAMIC_RELOCATION_P.
* elf64-x86-64.c (X86_SIZE_TYPE_P): New.
(elf_x86_64_relocate_section): Use GENERATE_DYNAMIC_RELOCATION_P.
* elfxx-x86.h (GENERATE_DYNAMIC_RELOCATION_P): New.
Add POINTER_LOCAL_IFUNC_P which returns TRUE for pointer reference to
local IFUNC symbol. Add PLT_LOCAL_IFUNC_P which returns TRUE for PLT
reference to local IFUNC symbol.
* elfxx-x86.h (POINTER_LOCAL_IFUNC_P): New.
(PLT_LOCAL_IFUNC_P): Likewise.
* elf32-i386.c (elf_i386_relocate_section): Use them.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
Add GENERATE_RELATIVE_RELOC_P which returns TRUE if dynamic relative
relocation should be generated.
* elfxx-x86.h (GENERATE_RELATIVE_RELOC_P): New.
* elf32-i386.c (elf_i386_relocate_section): Use it.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
Add TLS_TRANSITION_IE_TO_LE_P which returns TRUE if TLS IE->LE transition
is OK.
* elfxx-x86.h (TLS_TRANSITION_IE_TO_LE_P): New.
* elf32-i386.c (elf_i386_tls_transition): Use it.
* elf64-x86-64.c (elf_x86_64_tls_transition): Likewise.
bfd/
PR ld/22135
* elf32-i386.c (elf_i386_convert_load_reloc): Add an argument
to indicate if conversion is performed.
(elf_i386_check_relocs): Cache section contents and relocations
if conversion is performed.
* elf64-x86-64.c (elf_x86_64_check_relocs): Cache section
contents and relocations if conversion is performed.
ld/
PR ld/22135
* testsuite/ld-i386/i386.exp: Run pr22135.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr22135.d: New file.
* testsuite/ld-i386/pr22135.s: Likewise.
* testsuite/ld-x86-64/pr22135.d: Likewise.
* testsuite/ld-x86-64/pr22135.s: Likewise.
Since the only information which SYMBOL_REFERENCES_LOCAL_P doesn't check
is relocations, UNDEFINED_WEAK_RESOLVED_TO_ZERO only needs to check for
relocations with SYMBOL_REFERENCES_LOCAL_P.
* elf32-i386.c (elf_i386_relocate_section): Update usage of
UNDEFINED_WEAK_RESOLVED_TO_ZERO.
(elf_i386_finish_dynamic_symbol): Likewise.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
(elf_x86_64_finish_dynamic_symbol): Likewise.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Likewise.
(_bfd_x86_elf_fixup_symbol): Likewise.
After _bfd_i386_elf_convert_load and _bfd_x86_64_elf_convert_load are
removed, elf_i386_convert_load_reloc and elf_x86_64_convert_load_reloc
see __ehdr_start as an undefined symbol when they are called from
check_relocs to convert GOT relocations against local symbols. But
__ehdr_start will be defined as a hidden symbol by linker at the later
stage if it is referenced. This patch marks __ehdr_start as a defined
local symbol at the start of check_relocs if it is referenced and not
defined.
bfd/
PR ld/22115
* elf32-i386.c (elf_i386_convert_load_reloc): Check linker_def.
Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Check
linker_def. Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
* elfxx-x86.c (_bfd_x86_elf_link_check_relocs): Set local_ref
and linker_def on __ehdr_start if it is referenced and not
defined.
(_bfd_x86_elf_link_symbol_references_local): Also set local_ref
and return TRUE when building executable, if a symbol has
non-GOT/non-PLT relocations in text section or there is no
dynamic linker.
* elfxx-x86.h (elf_x86_link_hash_entry): Add linker_def.
ld/
PR ld/22115
* ld-i386/i386.exp: Run PR ld/22115 tests,
* ld/testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr22115-1.s: New file.
* testsuite/ld-i386/pr22115-1a.d: Likewise.
* testsuite/ld-i386/pr22115-1b.d: Likewise.
* testsuite/ld-i386/pr22115-1c.d: Likewise.
* testsuite/ld-i386/pr22115-1d.d: Likewise.
* testsuite/ld-x86-64/pr22115-1.s: Likewise.
* testsuite/ld-x86-64/pr22115-1a-x32.d: Likewise.
* testsuite/ld-x86-64/pr22115-1a.d: Likewise.
* testsuite/ld-x86-64/pr22115-1b-x32.d: Likewise.
* testsuite/ld-x86-64/pr22115-1b.d: Likewise.
* testsuite/ld-x86-64/pr22115-1c-x32.d: Likewise.
* testsuite/ld-x86-64/pr22115-1c.d: Likewise.
* testsuite/ld-x86-64/pr22115-1d-x32.d: Likewise.
* testsuite/ld-x86-64/pr22115-1d.d: Likewise.
Don't set r_info and r_sym fields in _bfd_x86_elf_link_hash_table_create.
Instead, set them in _bfd_x86_elf_link_setup_gnu_properties. We can
avoid adding elf64-x86-64.lo and elf64.lo together with elfxx-x86.lo to
bfd_backends.
* configure.ac (bfd_backends): Don't add elf64-x86-64.lo nor
elf64.lo together with elfxx-x86.lo for 64-bit BFD.
* configure: Regenerated.
* elf32-i386.c (elf_i386_link_setup_gnu_properties): Set r_info
and r_sym fields of plt_layout.
* elf64-x86-64.c (elf_x86_64_link_setup_gnu_properties):
Likewise.
* elfxx-x86.c (elf_x86_64_is_reloc_section): Remove BFD64 check.
(_bfd_x86_elf_link_hash_table_create): Likewise. Don't set
r_info nor r_sym fields.
(_bfd_x86_elf_link_setup_gnu_properties): Set r_info and r_sym
fields of htab.
* elfxx-x86.h (elf_x86_plt_layout_table): Add r_info and r_sym.
Instead of converting GOT relocations when sizing dynamic sections, we
convert GOT relocations during relocation check. Add a field, local_ref,
to elf_x86_link_hash_entry to indicate if symbol references are always
local with a new function to check if symbol references are always local,
which works in check_relocs.
* elf32-i386.c (elf_i386_convert_load_reloc): Add an argument,
r_type_p. Remove the converted argument. Replace
SYMBOL_REFERENCES_LOCAL with SYMBOL_REFERENCES_LOCAL_P. Return
the new relocation type via r_type_p.
(elf_i386_relocate_section): Likewise.
(elf_i386_finish_dynamic_symbol): Likewise.
(need_convert_load): Removed.
(check_relocs_failed): Updated.
(elf_i386_check_relocs): Call elf_i386_convert_load_reloc,
instead of setting need_convert_load.
(_bfd_i386_elf_convert_load): Removed.
* elf64-x86-64.c (need_convert_load): Removed.
(check_relocs_failed): Updated.
(elf_x86_64_convert_load_reloc): Add an argument, r_type_p.
Replace SYMBOL_REFERENCES_LOCAL with SYMBOL_REFERENCES_LOCAL_P.
Return the new relocation type via r_type_p.
(elf_x86_64_check_relocs): Call elf_x86_64_convert_load_reloc,
instead of setting need_convert_load.
(elf_x86_64_check_relocs): Don't check PIC if relocation has
been converted.
(_bfd_x86_64_elf_convert_load): Removed.
(elf_x86_64_relocate_section): Replace SYMBOL_REFERENCES_LOCAL
with SYMBOL_REFERENCES_LOCAL_P.
(elf_x86_64_finish_dynamic_symbol): Likewise.
* elfxx-x86.c (_bfd_x86_elf_link_hash_table_create): Don't
set convert_load.
(_bfd_x86_elf_size_dynamic_sections): Don't call convert_load.
(_bfd_x86_elf_link_symbol_references_local): New function.
* elfxx-x86.h (SYMBOL_REFERENCES_LOCAL_P): New.
(UNDEFINED_WEAK_RESOLVED_TO_ZERO): Replace elf.forced_local with
SYMBOL_REFERENCES_LOCAL_P.
(elf_x86_link_hash_entry): Add local_ref.
(elf_x86_link_hash_table): Remove convert_load.
(_bfd_i386_elf_convert_load): Removed.
(_bfd_x86_64_elf_convert_load): Likewise.
(_bfd_x86_elf_link_symbol_references_local): New.
Don't change r_type when performing TLS transitions to avoid getting
the relocation type with ELF32_R_TYPE again.
* elf32-i386.c (elf_i386_relocate_section): Don't change r_type
when calling elf_i386_tls_transition. Don't use ELF32_R_TYPE
to get the relocation type again.
* elf64-x86-64.c (elf_x86_64_relocate_section): Don't change
r_type when calling elf_x86_64_tls_transition. Don't use
ELF32_R_TYPE to get the relocation type again.
elf_i386_size_dynamic_sections and elf_x86_64_size_dynamic_sections are
very similar, except for the followings:
1. elf_i386_size_dynamic_sections checks GOT_TLS_IE and GOT_TLS_IE_BOTH.
elf_x86_64_size_dynamic_sections checks only GOT_TLS_IE. Since
GOT_TLS_IE_BOTH is never true for x86-64, it is OK to check GOT_TLS_IE
for both i386 and x86-64.
2, x86-64 sets tlsdesc_plt, but i386 doesn't. We set tlsdesc_plt only
if target_id == X86_64_ELF_DATA.
3. x86-64 has
if (s != htab->elf.srelplt)
s->reloc_count = 0;
and i386 has
s->reloc_count = 0;
i386 did have
if (s != htab->srelplt)
s->reloc_count = 0;
in the original commit:
commit 67a4f2b710
Author: Alexandre Oliva <aoliva@redhat.com>
Date: Wed Jan 18 21:07:51 2006 +0000
But it was removed by
commit 5ae0bfb60a
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date: Tue Feb 28 07:16:12 2006 +0000
bfd/
* elf32-i386.c (elf_i386_link_hash_table): Add next_tls_desc_index.
(elf_i386_link_hash_table_create): Initialize it.
(elf_i386_compute_jump_table_size): Use it instead of
srelplt->reloc_count.
(allocate_dynrelocs): Likewise.
(elf_i386_size_dynamic_sections): Likewise.
(elf_i386_relocate_section): Likewise.
A later commit:
commit e1f987424b
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Fri Oct 21 15:13:37 2011 +0000
Put IRELATIVE relocations after JUMP_SLOT.
bfd/
2011-10-21 H.J. Lu <hongjiu.lu@intel.com>
PR ld/13302
* elf32-i386.c (elf_i386_link_hash_table): Add next_jump_slot_index
and next_irelative_index.
(elf_i386_link_hash_table_create): Initialize next_jump_slot_index
and next_irelative_index.
(elf_i386_allocate_dynrelocs): Increment reloc_count instead of
next_tls_desc_index.
(elf_i386_size_dynamic_sections): Set next_tls_desc_index and
next_irelative_index from reloc_count.
(elf_i386_finish_dynamic_symbol): Put R_386_IRELATIVE after
R_386_JUMP_SLOT.
changed it back to use reloc_count again. So it is correct to use
if (s != htab->elf.srelplt)
s->reloc_count = 0;
for both i386 and x86-64 now.
4. i386 and x86-64 use different DT_XXXs. They are handled by adding
them to elf_x86_link_hash_table.
With these changes, we can share _bfd_x86_elf_size_dynamic_sections in
elf32-i386.c and elf64-x86-64.c.
* elf32-i386.c (elf_i386_convert_load): Renamed to ...
(_bfd_i386_elf_convert_load): This. Remove static.
(elf_i386_size_dynamic_sections): Removed.
(elf_backend_size_dynamic_sections): Likewise.
* elf64-x86-64.c (elf_x86_64_convert_load): Renamed to ...
(_bfd_x86_64_elf_convert_load): This. Remove static.
(elf_x86_64_size_dynamic_sections): Removed.
(elf_backend_size_dynamic_sections): Likewise.
* elfxx-x86.c (_bfd_x86_elf_allocate_dynrelocs): Renamed to ...
(elf_x86_allocate_dynrelocs): This. Make it static.
(_bfd_x86_elf_allocate_local_dynrelocs): Renamed to ...
(elf_x86_allocate_local_dynreloc): This. Make it static.
(elf_i386_is_reloc_section): New function.
(elf_x86_64_is_reloc_section): Likewise.
(_bfd_x86_elf_link_hash_table_create): Initialize convert_load,
is_reloc_section, dt_reloc, dt_reloc_sz and dt_reloc_ent.
Rearrange got_entry_size initialization.
(_bfd_x86_elf_size_dynamic_sections): New function.
* elfxx-x86.h (elf_x86_link_hash_table): Add convert_load,
is_reloc_section, dt_reloc, dt_reloc_sz and dt_reloc_ent.
(_bfd_i386_elf_convert_load): New.
(_bfd_x86_64_elf_convert_load): Likewise.
(_bfd_x86_elf_size_dynamic_sections): Likewise.
(elf_backend_size_dynamic_sections): Likewise.
(_bfd_x86_elf_allocate_dynrelocs): Removed.
(_bfd_x86_elf_allocate_local_dynrelocs): Likewise.
elf_i386_size_dynamic_sections has
htab->next_tls_desc_index = htab->elf.srelplt->reloc_count;
htab->sgotplt_jump_table_size = htab->next_tls_desc_index * 4;
This patch changes it to
htab->sgotplt_jump_table_size
= elf_x86_compute_jump_table_size (htab)
Since elf_x86_compute_jump_table_size is defined as
((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size)
there is no change in output. It makes elf_i386_size_dynamic_sections
the same as elf_x86_64_size_dynamic_sections.
* elf32-i386.c (elf_i386_size_dynamic_sections): Set
sgotplt_jump_table_size with elf_x86_compute_jump_table_size.
Since PLT_CIE_LENGTH, PLT_FDE_LENGTH, PLT_FDE_START_OFFSET and
PLT_FDE_LEN_OFFSET are identical in elf32-i386.c and elf64-x86-64.c,
they can be defined in elfxx-x86.h.
* elf32-i386.c (PLT_CIE_LENGTH, PLT_FDE_LENGTH,
PLT_FDE_START_OFFSET, PLT_FDE_LEN_OFFSET): Moved to ...
* elfxx-x86.h (PLT_CIE_LENGTH, PLT_FDE_LENGTH,
PLT_FDE_START_OFFSET, PLT_FDE_LEN_OFFSET): Here.
* elf64-x86-64.c (PLT_CIE_LENGTH, PLT_FDE_LENGTH,
PLT_FDE_START_OFFSET, PLT_FDE_LEN_OFFSET): Removed.
Extract the common parts of elf_i386_link_setup_gnu_properties and
elf_x86_64_link_setup_gnu_properties into a new function.
For x86-64, since PIC PLT layouts are the same as non-PIC PLT layouts,
initialize pic_plt0_entry and pic_plt_entry fields in PLT layouts with
the non-PIC PLT entries.
* elf32-i386.c (elf_i386_link_setup_gnu_properties): Updated.
Call _bfd_x86_elf_link_setup_gnu_properties.
* elf64-x86-64.c (elf_x86_lazy_plt_layout): Initialize
pic_plt0_entry and pic_plt_entry fields with the non-PIC PLT
entries.
(elf_x86_64_non_lazy_plt): Likewise.
(elf_x86_64_lazy_bnd_plt): Likewise.
(elf_x86_64_non_lazy_bnd_plt): Likewise.
(elf_x86_64_lazy_ibt_plt): Likewise.
(elf_x32_lazy_ibt_plt): Likewise.
(elf_x86_64_non_lazy_ibt_plt): Likewise.
(elf_x32_non_lazy_ibt_plt): Likewise.
(elf_x86_64_nacl_plt): Likewise.
(elf_x86_64_link_setup_gnu_properties): Updated. Call
_bfd_x86_elf_link_setup_gnu_properties.
* elfxx-x86.c: Include elf-vxworks.h".
(_bfd_x86_elf_link_setup_gnu_properties): New function.
* elfxx-x86.h (elf_x86_lazy_plt_layout): Remove "for i386 only"
comments for pic_plt0_entry and pic_plt_entry.
(elf_x86_non_lazy_plt_layout): Likewise.
(elf_x86_plt_layout_table): New.
(_bfd_x86_elf_link_setup_gnu_properties): Likewise.
We shpouldn't generate copy relocation to resolve reference to protected
data symbol defined in shared object with the NO_COPY_ON_PROTECTED
property. This patch adds a bit to elf_obj_tdata as well as
elf_i386_link_hash_entry and elf_x86_64_link_hash_entry to track the bfd
with the NO_COPY_ON_PROTECTED property as well as protected symbol
defined in shared object. extern_protected_data is set to FALSE if any
input relocatable file contains the NO_COPY_ON_PROTECTED property.
bfd/
PR ld/21997
* elf-bfd.h (elf_obj_tdata): Use ENUM_BITFIELD on object_id,
dyn_lib_class and has_gnu_symbols. Change bad_symtab to bitfield.
Add a has_no_copy_on_protected bitfield.
(elf_has_no_copy_on_protected): New.
* elf-properties.c (_bfd_elf_parse_gnu_properties): Set
elf_has_no_copy_on_protected for GNU_PROPERTY_NO_COPY_ON_PROTECTED.
(elf_merge_gnu_property_list): Likewise.
(_bfd_elf_link_setup_gnu_properties): Set extern_protected_data
to FALSE for elf_has_no_copy_on_protected.
* elf32-i386.c (SYMBOL_NO_COPYRELOC): New.
(elf_i386_link_hash_entry): Add def_protected.
(elf_i386_adjust_dynamic_symbol): Also check SYMBOL_NO_COPYRELOC
when checking info->nocopyreloc.
(elf_i386_link_setup_gnu_properties): Don't set
extern_protected_data here.
(elf_i386_merge_symbol_attribute): New function.
(elf_backend_merge_symbol_attribute): New.
* elf64-x86-64.c (SYMBOL_NO_COPYRELOC): New.
(elf_x86_64_link_hash_entry): Add def_protected.
(elf_x86_64_need_pic): Report protected symbol for def_protected.
(elf_x86_64_adjust_dynamic_symbol): Also check SYMBOL_NO_COPYRELOC
when checking info->nocopyreloc.
(elf_x86_64_relocate_section): Also check for R_X86_64_PC32
relocation run-time overflow and unresolvable R_X86_64_32S
relocation against protected data symbol defined in shared object
with GNU_PROPERTY_NO_COPY_ON_PROTECTED.
(elf_x86_64_link_setup_gnu_properties): Don't set
extern_protected_data here.
(elf_x86_64_merge_symbol_attribute): New function.
(elf_backend_merge_symbol_attribute): New.
ld/
PR ld/21997
* testsuite/ld-i386/i386.exp: Run PR ld/21997 tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr21997-1a.S: New file.
* testsuite/ld-i386/pr21997-1b.c: Likewise.
* testsuite/ld-i386/pr21997-1c.S: Likewise.
* testsuite/ld-x86-64/pr21997-1a.S: Likewise.
* testsuite/ld-x86-64/pr21997-1a.err: Likewise.
* testsuite/ld-x86-64/pr21997-1b.c: Likewise.
* testsuite/ld-x86-64/pr21997-1b.err: Likewise.
* testsuite/ld-x86-64/pr21997-1c.c: Likewise.
* elf32-i386.c (elf_i386_check_relocs): Revert the last change.
Undefined symbols may not have a type.
* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.
Since PLT entry is needed only for function symbols, increment PLT count
only for function symbols.
* elf32-i386.c (elf_i386_check_relocs): Increment PLT count only
for function symbols.
* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.
When GNU_PROPERTY_NO_COPY_ON_PROTECTED is set, it indicates that there
are no copy relocations against protected data symbols. When linker
sees GNU_PROPERTY_NO_COPY_ON_PROTECTED on any input relocatable file,
it sets extern_protected_data to FALSE.
bfd/
* elf32-i386.c (elf_i386_link_setup_gnu_properties): Set
extern_protected_data to FALSE if GNU_PROPERTY_NO_COPY_ON_PROTECTED
is set on any input relocatable file.
* elf64-x86-64.c (elf_x86_64_link_setup_gnu_properties): Likewise.
ld/
* testsuite/ld-i386/i386.exp: Run protected7.
* testsuite/ld-i386/protected7.d: New file.
* testsuite/ld-i386/protected7.s: Likewise.
* testsuite/ld-x86-64/protected8.d: Likewise.
* testsuite/ld-x86-64/protected8.s: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run protected8.
When synthesizing symbols for PLT entries, allocate space for symbol
names with @plt suffixes together with symbol table so that all memory
is returned when symbol table is freed.
PR binutils/21943
* elf32-i386.c (elf_i386_get_synthetic_symtab): Allocate space
for @plt suffixes first.
* elf64-x86-64.c (elf_x86_64_get_synthetic_symtab): Likewise.
PR 21884
* elf32-i386.c (elf_i386_link_setup_gnu_properties): If the dynobj
has not been set then use the bfd returned by
_bfd_elf_link_setup_gnu_properties. If that is null then search
through all the input bfds selecting the first normal, ELF format
one.
* elf64-x86-64.c (elf_x86_64_link_setup_gnu_properties): Likewise.
Instead of checking if a symbol is __tls_get_addr or ___tls_get_addr,
we check if there is a reference to __tls_get_addr or ___tls_get_addr
before starting relocation check.
* elf32-i386.c (elf_i386_link_hash_entry): Change tls_get_addr
to 1 bit.
(elf_i386_link_hash_newfunc): Initialize tls_get_addr to 0.
(elf_i386_check_tls_transition): Check tls_get_addr directly.
(elf_i386_convert_load_reloc): Update tls_get_addr check.
(elf_i386_link_check_relocs): New function.
(bfd_elf32_bfd_link_check_relocs): New.
* elf64-x86-64.c (elf_x86_64_link_hash_entry): Change tls_get_addr
to 1 bit.
(elf_x86_64_link_hash_newfunc): Initialize tls_get_addr to 0.
(elf_x86_64_check_tls_transition): Check tls_get_addr directly.
(elf_x86_64_convert_load_reloc): Update tls_get_addr check.
(elf_x86_64_link_check_relocs): New function.
(bfd_elf64_bfd_link_check_relocs): New.
(bfd_elf32_bfd_link_check_relocs): Likewise.
Local undefined weak symbol should always be resolved to 0.
* elf32-i386.c (UNDEFINED_WEAK_RESOLVED_TO_ZERO): Resolve
local undefined weak symbol to 0.
* elf64-x86-64.c (UNDEFINED_WEAK_RESOLVED_TO_ZERO): Likewise.
To support IBT in Intel Control-flow Enforcement Technology (CET)
instructions:
https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf
#define GNU_PROPERTY_X86_FEATURE_1_AND 0xc0000002
#define GNU_PROPERTY_X86_FEATURE_1_IBT (1U << 0)
are added to GNU program properties to indicate that all executable
sections are compatible with IBT when ENDBR instruction starts each
valid target where an indirect branch instruction can land.
GNU_PROPERTY_X86_FEATURE_1_IBT is set on output only if it is set on
all relocatable inputs.
The followings changes are made to the Procedure Linkage Table (PLT):
1. For 64-bit x86-64, PLT is changed to
PLT0: push GOT[1]
bnd jmp *GOT[2]
nop
...
PLTn: endbr64
push namen_reloc_index
bnd jmp PLT0
together with the second PLT section:
PLTn: endbr64
bnd jmp *GOT[namen_index]
nop
BND prefix is also added so that IBT-enabled PLT is compatible with MPX.
2. For 32-bit x86-64 (x32) and i386, PLT is changed to
PLT0: push GOT[1]
jmp *GOT[2]
nop
...
PLTn: endbr64 # endbr32 for i386.
push namen_reloc_index
jmp PLT0
together with the second PLT section:
PLTn: endbr64 # endbr32 for i386.
jmp *GOT[namen_index]
nop
BND prefix isn't used since MPX isn't supported on x32 and BND registers
aren't used in parameter passing on i386.
GOT is an array of addresses. Initially, GOT[namen_index] is filled
with the address of the ENDBR instruction of the corresponding entry
in the first PLT section. The function, namen, is called via the
ENDBR instruction in the second PLT entry. GOT[namen_index] is updated
to the actual address of the function, namen, at run-time.
2 linker command line options are added:
1. -z ibtplt: Generate IBT-enabled PLT.
2. -z ibt: Generate GNU_PROPERTY_X86_FEATURE_1_IBT in GNU program
properties as well as IBT-enabled PLT.
bfd/
* elf32-i386.c (elf_i386_lazy_ibt_plt0_entry): New.
(elf_i386_lazy_ibt_plt_entry): Likewise.
(elf_i386_pic_lazy_ibt_plt0_entry): Likewise.
(elf_i386_non_lazy_ibt_plt_entry): Likewise.
(elf_i386_pic_non_lazy_ibt_plt_entry): Likewise.
(elf_i386_eh_frame_lazy_ibt_plt): Likewise.
(elf_i386_lazy_plt_layout): Likewise.
(elf_i386_non_lazy_plt_layout): Likewise.
(elf_i386_link_hash_entry): Add plt_second.
(elf_i386_link_hash_table): Add plt_second and
plt_second_eh_frame.
(elf_i386_allocate_dynrelocs): Use the second PLT if needed.
(elf_i386_size_dynamic_sections): Use .plt.got unwind info for
the second PLT. Check the second PLT.
(elf_i386_relocate_section): Use the second PLT to resolve
PLT reference if needed.
(elf_i386_finish_dynamic_symbol): Fill and use the second PLT if
needed.
(elf_i386_finish_dynamic_sections): Set sh_entsize on the
second PLT. Generate unwind info for the second PLT.
(elf_i386_plt_type): Add plt_second.
(elf_i386_get_synthetic_symtab): Support the second PLT.
(elf_i386_parse_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND.
(elf_i386_merge_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND. If info->ibt is set, turn
on GNU_PROPERTY_X86_FEATURE_1_IBT
(elf_i386_link_setup_gnu_properties): If info->ibt is set,
turn on GNU_PROPERTY_X86_FEATURE_1_IBT. Use IBT-enabled PLT
for info->ibtplt, info->ibt or GNU_PROPERTY_X86_FEATURE_1_IBT
is set on all relocatable inputs.
* elf64-x86-64.c (elf_x86_64_lazy_ibt_plt_entry): New.
(elf_x32_lazy_ibt_plt_entry): Likewise.
(elf_x86_64_non_lazy_ibt_plt_entry): Likewise.
(elf_x32_non_lazy_ibt_plt_entry): Likewise.
(elf_x86_64_eh_frame_lazy_ibt_plt): Likewise.
(elf_x32_eh_frame_lazy_ibt_plt): Likewise.
(elf_x86_64_lazy_ibt_plt): Likewise.
(elf_x32_lazy_ibt_plt): Likewise.
(elf_x86_64_non_lazy_ibt_plt): Likewise.
(elf_x32_non_lazy_ibt_plt): Likewise.
(elf_x86_64_get_synthetic_symtab): Support the second PLT.
(elf_x86_64_parse_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND.
(elf_x86_64_merge_gnu_properties): Support
GNU_PROPERTY_X86_FEATURE_1_AND. If info->ibt is set, turn
on GNU_PROPERTY_X86_FEATURE_1_IBT
(elf_x86_64_link_setup_gnu_properties): If info->ibt is set,
turn on GNU_PROPERTY_X86_FEATURE_1_IBT. Use IBT-enabled PLT
for info->ibtplt, info->ibt or GNU_PROPERTY_X86_FEATURE_1_IBT
is set on all relocatable inputs.
binutils/
* readelf.c (decode_x86_feature): New.
(print_gnu_property_note): Call decode_x86_feature on
GNU_PROPERTY_X86_FEATURE_1_AND.
* testsuite/binutils-all/i386/empty.d: New file.
* testsuite/binutils-all/i386/empty.s: Likewise.
* testsuite/binutils-all/i386/ibt.d: Likewise.
* testsuite/binutils-all/i386/ibt.s: Likewise.
* testsuite/binutils-all/x86-64/empty-x32.d: Likewise.
* testsuite/binutils-all/x86-64/empty.d: Likewise.
* testsuite/binutils-all/x86-64/empty.s: Likewise.
* testsuite/binutils-all/x86-64/ibt-x32.d: Likewise.
* testsuite/binutils-all/x86-64/ibt.d: Likewise.
* testsuite/binutils-all/x86-64/ibt.s: Likewise.
include/
* bfdlink.h (bfd_link_info): Add ibtplt and ibt.
* elf/common.h (GNU_PROPERTY_X86_FEATURE_1_AND): New.
(GNU_PROPERTY_X86_FEATURE_1_IBT): Likewise.
ld/
* Makefile.am (ELF_X86_DEPS): Add $(srcdir)/emulparams/cet.sh.
* Makefile.in: Regenerated.
* NEWS: Mention GNU_PROPERTY_X86_FEATURE_1_IBT, -z ibtplt
and -z ibt.
* emulparams/cet.sh: New file.
* testsuite/ld-i386/ibt-plt-1.d: Likewise.
* testsuite/ld-i386/ibt-plt-1.s: Likewise.
* testsuite/ld-i386/ibt-plt-2.s: Likewise.
* testsuite/ld-i386/ibt-plt-2a.d: Likewise.
* testsuite/ld-i386/ibt-plt-2b.d: Likewise.
* testsuite/ld-i386/ibt-plt-2c.d: Likewise.
* testsuite/ld-i386/ibt-plt-2d.d: Likewise.
* testsuite/ld-i386/ibt-plt-3.s: Likewise.
* testsuite/ld-i386/ibt-plt-3a.d: Likewise.
* testsuite/ld-i386/ibt-plt-3b.d: Likewise.
* testsuite/ld-i386/ibt-plt-3c.d: Likewise.
* testsuite/ld-i386/ibt-plt-3d.d: Likewise.
* testsuite/ld-i386/plt-main-ibt.dd: Likewise.
* testsuite/ld-i386/plt-pie-ibt.dd: Likewise.
* testsuite/ld-i386/property-x86-empty.s: Likewise.
* testsuite/ld-i386/property-x86-ibt.s: Likewise.
* testsuite/ld-i386/property-x86-ibt1a.d: Likewise.
* testsuite/ld-i386/property-x86-ibt1b.d: Likewise.
* testsuite/ld-i386/property-x86-ibt2.d: Likewise.
* testsuite/ld-i386/property-x86-ibt3a.d: Likewise.
* testsuite/ld-i386/property-x86-ibt3b.d: Likewise.
* testsuite/ld-i386/property-x86-ibt4.d: Likewise.
* testsuite/ld-i386/property-x86-ibt5.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-1.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-2.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-2a-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2a.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2b-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2b.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2c-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2c.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2d-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-2d.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3.s: Likewise.
* testsuite/ld-x86-64/ibt-plt-3a-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3a.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3b-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3b.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3c-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3c.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3d-x32.d: Likewise.
* testsuite/ld-x86-64/ibt-plt-3d.d: Likewise.
* testsuite/ld-x86-64/plt-main-ibt-now.rd: Likewise.
* testsuite/ld-x86-64/plt-main-ibt-x32.dd: Likewise.
* testsuite/ld-x86-64/plt-main-ibt.dd: Likewise.
* testsuite/ld-x86-64/property-x86-empty.s: Likewise.
* testsuite/ld-x86-64/property-x86-ibt.s: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1a-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1a.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1b-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt1b.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt2-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt2.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3a-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3a.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3b-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt3b.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt4-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt4.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt5-x32.d: Likewise.
* testsuite/ld-x86-64/property-x86-ibt5.d: Likewise.
* emulparams/elf32_x86_64.sh: Source emulparams/cet.sh.
(TINY_READONLY_SECTION): Add .plt.sec.
* emulparams/elf_i386.sh: Likewise.
* emulparams/elf_x86_64.sh: Source emulparams/cet.sh.
* ld.texinfo: Document -z ibtplt and -z ibt.
* testsuite/ld-i386/i386.exp: Run IBT and IBT PLT tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-x86-64/pr21481b.S (check): Updated for x32.
