Address of protected data defined in the shared library may be external,
i.e., due to copy relocation. By default, linker backend checks if
relocations against protected data symbols are valid for building shared
library and issues an error if relocation isn't allowed. The new option
override linker backend default. When -z noextern-protected-data is used,
updates on protected data symbols by another module won't be visibile
to the resulting shared library. This option is specific to ELF/i386
and ELF/x86-64.
bfd/
PR ld/pr17709
* elflink.c (_bfd_elf_adjust_dynamic_copy): Check
info->extern_protected_data when warning copy relocs against
protected symbols.
(_bfd_elf_symbol_refs_local_p): Check info->extern_protected_data
when checking protected non-function symbols.
include/
PR ld/pr17709
* bfdlink.h (bfd_link_info): Add extern_protected_data.
ld/
PR ld/pr17709
* ld.texinfo: Document "-z noextern-protected-data".
* ldmain.c (main): Initialize link_info.extern_protected_data
to -1.
* lexsup.c (elf_shlib_list_options): Add
"-z [no]extern-protected-data".
* emulparams/elf32_x86_64.sh: Source extern_protected_data.sh.
* emulparams/elf_i386.sh: Likewise.
* emulparams/elf_i386_be.sh: Likewise.
* emulparams/elf_i386_chaos.sh: Likewise.
* emulparams/elf_i386_ldso.sh: Likewise.
* emulparams/elf_i386_vxworks.sh: Likewise.
* emulparams/elf_k1om.sh: Likewise.
* emulparams/elf_l1om.sh: Likewise.
* emulparams/elf_x86_64.sh: Source extern_protected_data.sh.
(PARSE_AND_LIST_OPTIONS): Renamed to ...
(PARSE_AND_LIST_OPTIONS_BNDPLT): This.
(PARSE_AND_LIST_ARGS_CASE_Z): Renamed to ...
(PARSE_AND_LIST_ARGS_CASE_Z_BNDPLT): This.
(PARSE_AND_LIST_OPTIONS): Append $PARSE_AND_LIST_OPTIONS_BNDPLT.
(PARSE_AND_LIST_ARGS_CASE_Z): Append
$PARSE_AND_LIST_ARGS_CASE_Z_BNDPLT.
* emulparams/extern_protected_data.sh: New file.
ld/testsuite/
PR ld/pr17709
* ld-i386/i386.exp: Run protected6b.
* ld-i386/protected6b.d: New file.
* ld-x86-64/protected6b.d: Likewise.
* ld-x86-64/x86-64.exp: Run protected6b.
When checking R_386_GOTOFF/R_X86_64_GOTOFF64 for building shared library,
we should check SYMBOL_REFERENCES_LOCAL instead of SYMBOLIC_BIND to cover
more cases.
bfd/
* elf32-i386.c (elf_i386_relocate_section): Replace SYMBOLIC_BIND
with SYMBOL_REFERENCES_LOCAL when checking R_386_GOTOFF against
protected data symbol when building shared library.
* elf64-x86-64.c (elf_x86_64_relocate_section): Check
R_X86_64_GOTOFF64 against undefined symbol and replace
SYMBOLIC_BIND with SYMBOL_REFERENCES_LOCAL when checking
R_X86_64_GOTOFF64 against protected data symbol when building
shared library.
ld/testsuite/
* ld-i386/i386.exp: Run protected6a.
* ld-i386/protected6.d: Renamed to ...
* ld-i386/protected6a.d: This.
* ld-x86-64/hidden4.d: New file.
* ld-x86-64/hidden4.s: Likewise.
* ld-x86-64/hidden5.d: Likewise.
* ld-x86-64/hidden5.s: Likewise.
* ld-x86-64/protected6.d: Renamed to ...
* ld-x86-64/protected6a.d: This.
* ld-x86-64/x86-64.exp: Run hidden4, hidden5, protected6a,
protected7a and protected7b.
R_386_GOTOFF/R_X86_64_GOTOFF64 relocation shouldn't be used against
protected data symbol on x86 since with copy relocation, address of
protected data defined in the shared library may be external.
This patch will break building shared libraries with protected data
symbols using GCCs older than GCC 5 without the bug fix for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
GCC backport request should be made in the GCC bug report above.
bfd/
PR ld/pr17709
* elf32-i386.c (elf_i386_relocate_section): Also check R_386_GOTOFF
against protected data symbol when building shared library.
* elf64-x86-64.c (elf_x86_64_relocate_section): Also check
R_X86_64_GOTOFF64 against protected data symbol when building
shared library.
ld/testsuite/
PR ld/pr17709
* ld-i386/protected6.d: New file.
* ld-i386/protected6.s: Likewise.
* ld-x86-64/protected6.d: Likewise.
* ld-x86-64/protected6.s: Likewise.
* ld-x86-64/protected7.d: Likewise.
* ld-x86-64/protected7.s: Likewise.
* ld-x86-64/protected7a.d: Likewise.
* ld-x86-64/protected7b.d: Likewise.
Re-apply: commit ca3fe95e46
With copy relocation, address of protected data defined in the shared
library may be external. This patch adds extern_protected_data and
changes _bfd_elf_symbol_refs_local_p to return false for protected data
if extern_protected_data is true.
This patch will break building shared libraries with protected data
symbols using GCCs older than GCC 5 without the bug fix for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
GCC backport request should be made in the GCC bug report above.
To get correct run-time behavior on Linux, glibc 2.22 or above are
required, which have the bug fix for
https://sourceware.org/bugzilla/show_bug.cgi?id=17711
Backports for glibc 2.21, 2.20, 2.19 and 2.18 are on hjl/pr17711/2.21,
hjl/pr17711/2.20, hjl/pr17711/2.19 and hjl/pr17711/2.18 branches,
respectively, at
https://sourceware.org/git/?p=glibc.git;a=summary
bfd/
PR ld/pr15228
PR ld/pr17709
* elf-bfd.h (elf_backend_data): Add extern_protected_data.
* elf32-i386.c (elf_backend_extern_protected_data): New.
Defined to 1.
* elf64-x86-64.c (elf_backend_extern_protected_data): Likewise.
* elflink.c (_bfd_elf_adjust_dynamic_copy): Don't error on
copy relocs against protected symbols if extern_protected_data
is true.
(_bfd_elf_symbol_refs_local_p): Don't return true on protected
non-function symbols if extern_protected_data is true.
* elfxx-target.h (elf_backend_extern_protected_data): New.
Default to 0.
(elfNN_bed): Initialize extern_protected_data with
elf_backend_extern_protected_data.
ld/testsuite/
PR ld/pr15228
PR ld/pr17709
* ld-i386/i386.exp (i386tests): Add a test for PR ld/17709.
* ld-i386/pr17709-nacl.rd: New file.
* ld-i386/pr17709.rd: Likewise.
* ld-i386/pr17709a.s: Likewise.
* ld-i386/pr17709b.s: Likewise.
* ld-i386/protected3.d: Updated.
* ld-i386/protected3.s: Likewise.
* ld-x86-64/pr17709-nacl.rd: New file.
* ld-x86-64/pr17709.rd: Likewise.
* ld-x86-64/pr17709a.s: Likewise.
* ld-x86-64/pr17709b.s: Likewise.
* ld-x86-64/protected3.d: Updated.
* ld-x86-64/protected3.s: Likewise.
* ld-x86-64/x86-64.exp (x86_64tests): Add a test for PR ld/17709.
With copy relocation, address of protected data defined in the shared
library may be external. This patch adds extern_protected_data and
changes _bfd_elf_symbol_refs_local_p to return false for protected data
if extern_protected_data is true.
bfd/
PR ld/pr15228
PR ld/pr17709
* elf-bfd.h (elf_backend_data): Add extern_protected_data.
* elf32-i386.c (elf_backend_extern_protected_data): New.
Defined to 1.
* elf64-x86-64.c (elf_backend_extern_protected_data): Likewise.
* elflink.c (_bfd_elf_adjust_dynamic_copy): Don't error on
copy relocs against protected symbols if extern_protected_data
is true.
(_bfd_elf_symbol_refs_local_p): Don't return true on protected
non-function symbols if extern_protected_data is true.
* elfxx-target.h (elf_backend_extern_protected_data): New.
Default to 0.
(elfNN_bed): Initialize extern_protected_data with
elf_backend_extern_protected_data.
ld/testsuite/
PR ld/pr15228
PR ld/pr17709
* ld-i386/i386.exp (i386tests): Add a test for PR ld/17709.
* ld-i386/pr17709-nacl.rd: New file.
* ld-i386/pr17709.rd: Likewise.
* ld-i386/pr17709a.s: Likewise.
* ld-i386/pr17709b.s: Likewise.
* ld-i386/protected3.d: Updated.
* ld-i386/protected3.s: Likewise.
* ld-x86-64/pr17709-nacl.rd: New file.
* ld-x86-64/pr17709.rd: Likewise.
* ld-x86-64/pr17709a.s: Likewise.
* ld-x86-64/pr17709b.s: Likewise.
* ld-x86-64/protected3.d: Updated.
* ld-x86-64/protected3.s: Likewise.
* ld-x86-64/x86-64.exp (x86_64tests): Add a test for PR ld/17709.
When there are both PLT and GOT references to the same function symbol,
linker will create a GOTPLT slot for PLT entry and a GOT slot for GOT
reference. A run-time JUMP_SLOT relocation is created to update the
GOTPLT slot and a run-time GLOB_DAT relocation is created to update the
GOT slot. Both JUMP_SLOT and GLOB_DAT relocations will apply the same
symbol value to GOTPLT and GOT slots, respectively, at run-time.
This optimization combines GOTPLT and GOT slots into a single GOT slot
and removes the run-time JUMP_SLOT relocation. It replaces the regular
PLT entry:
indirect jump [GOTPLT slot]
push relocation index
jump PLT0
with an GOT PLT entry with an indirect jump via the GOT slot:
indirect jump [GOT slot]
nop
and resolves PLT reference to the GOT PLT entry.
We must avoid this optimization if pointer equality is needed since
we don't clear symbol value in this case and the dynamic linker won't
update the GOT slot. Otherwise, the resulting binary will get into an
infinite loop at run-time.
bfd/
* elf32-i386.c (elf_i386_got_plt_entry): New.
(elf_i386_pic_got_plt_entry): Likewise.
(elf_i386_link_hash_entry): Add plt_got.
(elf_i386_link_hash_table): Likewise.
(elf_i386_link_hash_newfunc): Initialize plt_got.offset to -1.
(elf_i386_get_local_sym_hash): Likewise.
(elf_i386_check_relocs): Create the GOT PLT if there are both
PLT and GOT references when the regular PLT is used.
(elf_i386_allocate_dynrelocs): Use the GOT PLT if there are
both PLT and GOT references unless pointer equality is needed.
(elf_i386_relocate_section): Also check the GOT PLT when
resolving R_386_PLT32.
(elf_i386_finish_dynamic_symbol): Use the GOT PLT if it is
available.
* elf64-x86-64.c (elf_x86_64_link_hash_entry): Add plt_got.
(elf_x86_64_link_hash_table): Likewise.
(elf_x86_64_link_hash_newfunc): Initialize plt_got.offset to -1.
(elf_x86_64_get_local_sym_hash): Likewise.
(elf_x86_64_check_relocs): Create the GOT PLT if there are both
PLT and GOT references when the regular PLT is used.
(elf_x86_64_allocate_dynrelocs): Use the GOT PLT if there are
both PLT and GOT references unless pointer equality is needed.
(elf_x86_64_relocate_section): Also check the GOT PLT when
resolving R_X86_64_PLT32.
(elf_x86_64_finish_dynamic_symbol): Use the GOT PLT if it is
available.
ld/
* emulparams/elf_i386.sh (TINY_READONLY_SECTION): New.
* emulparams/elf_x86_64.sh (TINY_READONLY_SECTION): Add .plt.got.
ld/testsuite/
* ld-i386/i386.exp: Add run-time relocation tests for plt-main.
* ld-i386/plt-main.rd: New file.
* ld-x86-64/plt-main-bnd.dd: Likewise.
* ld-x86-64/plt-main.rd: Likewise.
* ld-x86-64/x86-64.exp: Add run-time relocation tests for
plt-main.
Commit e1f987424b changed how
next_tls_desc_index was set up. This patch updates
elf_i386_compute_jump_table_size to use elf.srelplt->reloc_count
instead of next_tls_desc_index.
bfd/
PR ld/17057
* elf32-i386.c (elf_i386_compute_jump_table_size): Replace
next_tls_desc_index with elf.srelplt->reloc_count.
ld/testsuite/
PR ld/17057
* ld-i386/i386.exp: Run pr17057.
* ld-i386/pr17057.d: New file.
* ld-i386/pr17057.s: Likewise.
bfd/
2012-03-20 H.J. Lu <hongjiu.lu@intel.com>
PR ld/13880
* elf32-i386.c (elf_i386_relocate_section): Don't issue an error
for R_386_GOTOFF relocation against protected function if
SYMBOLIC_BIND is true.
* elf64-x86-64.c (elf_x86_64_relocate_section): Don't issue an
error for R_X86_64_GOTOFF64 relocation against protected function
when building executable or SYMBOLIC_BIND is true.
ld/testsuite/
2012-03-20 H.J. Lu <hongjiu.lu@intel.com>
PR ld/13880
* ld-i386/i386.exp: Run protected4 and protected5.
* ld-x86-64/x86-64.exp: Likewise.
* ld-i386/protected4.d: New.
* ld-i386/protected4.s: Likewise.
* ld-i386/protected5.d: Likewise.
* ld-i386/protected5.s: Likewise.
* ld-x86-64/protected4.d: Likewise.
* ld-x86-64/protected4.s: Likewise.
* ld-x86-64/protected5.d: Likewise.
* ld-x86-64/protected5.s: Likewise.
2009-06-19 H.J. Lu <hongjiu.lu@intel.com>
* elf32-i386.c (elf_i386_tls_transition): Add a parameter,
r_symndx. Report local symbol name on error.
(elf_i386_check_relocs): Updated. Report local symbol name on
error.
(elf_i386_gc_sweep_hook): Updated.
(elf_i386_relocate_section): Likewise.
* elf64-x86-64.c (elf64_x86_64_tls_transition): Add a parameter,
r_symndx. Report local symbol name on error.
(elf64_x86_64_check_relocs): Updated. Report local symbol name
on error.
(elf64_x86_64_gc_sweep_hook): Updated.
(elf64_x86_64_relocate_section): Likewise.
ld/testsuite/
2009-06-19 H.J. Lu <hongjiu.lu@intel.com>
* ld-i386/i386.exp: Run tlsgd2.
* ld-i386/tlsgd2.d: New.
* ld-i386/tlsgd2.s: Likewise.
* ld-x86-64/tlsgd3.d: Updated.
* common.h (STT_IFUNC): Define.
elfcpp/
* elfcpp.h (enum STT): Add STT_IFUNC.
bfd/
* syms.c (struct bfd_symbol): Add new flag BSF_INDIRECT_FUNCTION.
Remove redundant flag BFD_FORT_COMM_DEFAULT_VALUE. Renumber flags
to remove gaps.
(bfd_print_symbol_vandf): Return 'i' for BSF_INDIRECT_FUNCTION.
(bfd_decode_symclass): Likewise.
* elf.c (swap_out_syms): Translate BSF_INDIRECT_FUNCTION into
STT_IFUNC.
(elf_find_function): Treat STT_IFUNC in the same way as STT_FUNC.
(_bfd_elf_is_function_type): Likewise.
* elf32-arm.c (arm_elf_find_function): Likewise.
(elf32_arm_adjust_dynamic_symbol): Likewise.
(elf32_arm_swap_symbol_in): Likewise.
(elf32_arm_additional_program_headers): Likewise.
* elf32-i386.c (is_indirect_symbol): New function.
(elf_i386_check_relocs): Also generate dynamic relocs for
relocations against STT_IFUNC symbols.
(allocate_dynrelocs): Likewise.
(elf_i386_relocate_section): Likewise.
* elf64-x86-64.c (is_indirect_symbol): New function.
(elf64_x86_64_check_relocs): Also generate dynamic relocs for
relocations against STT_IFUNC symbols.
(allocate_dynrelocs): Likewise.
(elf64_x86_64_relocate_section): Likewise.
* elfcode.h (elf_slurp_symbol_table): Translate STT_IFUNC into
BSF_INDIRECT_FUNCTION.
* elflink.c (_bfd_elf_adjust_dynamic_reloc_section): Add support
for STT_IFUNC symbols.
(get_ifunc_reloc_section_name): New function.
(_bfd_elf_make_ifunc_reloc_section): New function.
* elf-bfd.h (struct bfd_elf_section_data): Add indirect_relocs field.
* bfd-in2.h: Regenerate.
gas/
* config/obj-elf.c (obj_elf_type): Add support for STT_IFUNC type.
* doc/as.texinfo: Document new feature.
* NEWS: Mention new feature.
gas/testsuite/
* gas/elf/type.s: Add test of STT_IFUNC symbol type.
* gas/elf/type.e: Update expected disassembly.
* gas/elf/elf.exp: Update grep of symbol types.
ld/
* NEWS: Mention new feature.
* pe-dll.c (process_def_file): Replace use of redundant
BFD_FORT_COMM_DEFAULT_VALUE with 0.
* scripttempl/elf.sc: Add .rel.ifunc.dyn and .rela.ifunc.dyn
sections.
ld/testsuite/
* ld-mips-elf/reloc-1-n32.d: Updated expected output for reloc
descriptions.
* ld-mips-elf/reloc-1-n64.d: Likewise.
* ld-i386/ifunc.d: New test.
* ld-i386/ifunc.s: Source file for the new test.
* ld-i386/i386.exp: Run the new test.
* ld-arm/vxworks1.ld: Swap .bss and .data.
* ld-arm/vxworks1-lib.rd: Update accordingly.
* ld-arm/vxworks1-lib.td: New test.
* ld-arm/arm-elf.exp: Run it.
* ld-i386/vxworks1.ld: Swap .bss and .data.
* ld-i386/vxworks1-lib.rd: Update accordingly.
* ld-i386/vxworks1-lib.td: New test.
* ld-i386/i386.exp: Run it.
* ld-mips-elf/vxworks1.ld: Swap .bss and .data.
* ld-mips-elf/vxworks1-lib.rd: Update accordingly.
* ld-mips-elf/vxworks1.rd: Likewise.
* ld-powerpc/vxworks1.ld: Swap .bss and .data.
* ld-powerpc/vxworks1-lib.rd: Update accordingly.
* ld-powerpc/vxworks1-lib.td: New test.
* ld-powerpc/powerpc.exp: Run it.
* ld-sh/vxworks1.ld: Swap .bss and .data.
* ld-sh/vxworks1-lib.rd: Update accordingly.
* ld-sh/vxworks1-lib.td: New test.
* ld-sh/sh-vxworks.exp: Run it.
* ld-sparc/vxworks1.ld: Swap .bss and .data.
* ld-sparc/vxworks1-lib.rd: Update accordingly.
* ld-sparc/vxworks1-lib.td: New test.
* ld-sparc/sparc.exp: Run it.
