The changes to reorder sections for better relro protection on powerpc64,
3e2b0f31, 23283c1b, and 5ad18f16, run into a problem with xlc.
xlc -qdatalocal puts global variables into .toc, which means that .toc
must be writable. The simplest way to accomplish this is to edit the
linker script to remove .toc sections from .got on detecting xlc object
files.
bfd/
* elf64-ppc.h (struct ppc64_elf_params): Add "object_in_toc".
* elf64-ppc.c (ppc64_elf_add_symbol_hook): Assume that global symbols
in .toc indicate xlc compiled code that might require a rw .toc.
ld/
* emulparams/elf64ppc.sh (INITIAL_READWRITE_SECTIONS): Define.
* emultempl/ppc64elf.em (params): Init new field.
(ppc_after_open): New function.
(LDEMUL_AFTER_OPEN): Define.
* ldlang.c (lang_final): Whitespace fix.
ld/testsuite/
* ld-powerpc/tocvar.d, * ld-powerpc/tocvar.s: New test.
* ld-powerpc/tocnovar.d, * ld-powerpc/tocnovar.s: New test.
* ld-powerpc/powerpc.exp: Run tocvar and tocnovar.
This patch allows the user to override powerpc64-ld's default for
providing linker generated register save and restore functions as used
by gcc -Os code. Normally these are not provided by ld -r, so Linux
kernel modules have needed to include their own copies.
bfd/
* 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.
ld/
* emultempl/ppc64elf.em (params): Init new field.
(ppc_create_output_section_statements): Set params.save_restore_funcs
default.
(PARSE_AND_LIST_*): Add support for --save-restore-funcs and
--no-save-restore-funcs.
Moves assorted variables used to communicate between ld and bfd into
a struct, hooks it into the bfd link_hash_table early, and removes
all other places where such variables were passed piecemeal.
bfd/
* 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".
ld/
* emultemps/ppc64elf.em (params): New static struct replacing
various other static vars. Adjust code throughout file.
* elf64-ppc.h (ppc64_elf_toc): Delete.
(ppc64_elf_set_toc): Declare.
* elf64-ppc.c (ppc64_elf_toc_reloc): Replace call to ppc64_elf_toc
with call the ppc64_elf_set_toc.
(ppc64_elf_toc_ha_reloc, ppc64_elf_toc64_reloc): Likewise.
(ppc64_elf_start_multitoc_partition): Likewise.
(struct ppc_link_hash_table): Delete dot_toc_dot. Replace all uses
with elf.hgot.
(ppc64_elf_process_dot_syms): Don't make a fake function descriptor
for ".TOC.".
(ppc64_elf_check_relocs): Mark sections with a reference to .TOC.
as needing a toc pointer.
(ppc64_elf_size_stubs): Don't set dot_toc_dot here.
(ppc64_elf_set_toc): Rename from ppc64_elf_toc. Add info param.
Set elf.hgot value.
ld/
* emultempl/ppc64elf.em: (ppc_layout_sections_again): Call
ppc64_elf_set_toc rather than ppc64_elf_toc/_bfd_set_gp_value.
(gld${EMULATION_NAME}_after_allocation): Likewise.
* elf64-ppc.c: Define more insns used in plt call stubs.
(ppc64_elf_brtaken_reloc): Assume isa version 2 or above.
(ppc64_elf_relocate_section): Likewise.
(enum ppc_stub_type): Add ppc_stub_plt_call_r2save.
(struct ppc_link_hash_table): Increase size of stub_count array.
Add plt_stub_align and plt_thread_safe.
(ALWAYS_USE_FAKE_DEP, ALWAYS_EMIT_R2SAVE): Define.
(plt_stub_size, plt_stub_pad): New functions.
(build_plt_stub): Emit barriers for power7 thread safety. Don't
emit needless save of r2.
(build_tls_get_addr_stub): Adjust params.
(ppc_build_one_stub): Handle ppc_stub_plt_call_r2save and aligning
plt stubs. Adjust build_*plt_stub calls.
(ppc_size_one_stub): Similarly.
(ppc64_elf_size_stubs): Accept plt_thread_safe and plt_stub_align
params. Choose default for plt_thread_safe based on existence of
calls to thread creation functions. Modify plt_call to
plt_call_r2save when no tocsave reloc found. Align tail of stub
sections.
(ppc64_elf_build_stubs): Align tail of stub sections. Adjust
output of stub statistics.
(ppc64_elf_relocate_section): Handle ppc_stub_plt_call_r2save.
* elf64-ppc.h (ppc64_elf_size_stubs): Update prototype.
ld/
* emultempl/ppc64elf.em (PARSE_AND_LIST_PROLOGUE,
PARSE_AND_LIST_LONGOPTS, PARSE_AND_LIST_OPTIONS,
PARSE_AND_LIST_ARGS_CASES): Handle --{no-,}plt-thread-safe and
--{no-,}plt-align.
(plt_thread_safe, plt_stub_align): New vars.
(gld${EMULATION_NAME}_after_allocation): Pass them to
ppc64_elf_size_stubs. Align stub sections according to plt_stub_align.
* ld.texinfo: Document new command line options, and an old
undocumented option.
PR ld/11378
* elf64-ppc.h (ppc64_elf_check_init_fini): Declare.
* elf64-ppc.c (call_check_done): Define.
(ppc64_elf_add_symbol_hook): Substitute bfd_get_section_name macro.
(ppc64_elf_check_relocs, ppc64_elf_size_dynamic_sections): Likewise.
(ppc64_elf_finish_multitoc_partition): Remove unnecessary check.
(toc_adjusting_stub_needed): Use call_check_done rather than toc_off.
Simplify return logic. Iterate over all .init and .fini fragments
by recursion. Set makes_toc_func_call here..
(ppc64_elf_next_input_section): ..rather than here.
(check_pasted_section, ppc64_elf_check_init_fini): New functions.
ld/
PR ld/11378
* emultempl/ppc64elf.em (gld${EMULATION_NAME}_after_allocation): Call
ppc64_elf_check_init_fini and warn if .init/.fini use different TOCs.
* elf64-ppc.c (struct plt_entry): Move earlier in file.
(struct got_entry): Likewise. Add is_indirect and got.ent fields.
(struct ppc64_elf_obj_tdata): Change tlsld_got to be a struct got_entry.
Update all uses.
(struct ppc_link_hash_table): Add got_reli_size and second_toc_pass.
Remove no_multi_toc.
(update_local_sym_info, ppc64_elf_check_relocs): Clear is_indirect
when allocating a new struct got_entry.
(allocate_got): New function, extracted from..
(allocate_dynrelocs): ..here. Abort on got entry in non-ppc64 bfd.
(ppc64_elf_size_dynamic_sections): Track got relocs allocated in
.reliplt by got_reli_size. Set owner on ppc64_tlsld_got entries.
(ppc64_elf_setup_section_lists): Remove output_bfd param and
no_multi_toc, add add_stub_section and layout_sections_again. Stash
new params in htab. Extract some code to..
(ppc64_elf_start_multitoc_partition): ..here. New function.
(ppc64_elf_next_toc_section): Check for linker script errors. Handle
second pass toc scan.
(merge_got_entries, merge_global_got, reallocate_got): New functions.
(ppc64_elf_reinit_toc): Rename to..
(ppc64_elf_finish_multitoc_partition): ..this.
(ppc64_elf_layout_multitoc): New function.
(ppc64_elf_size_stubs): Delete output_bfd, add_stub_section and
layout_sections_again params.
(ppc64_elf_relocate_section): Handle indirect got entries.
* elf64-ppc.h: Update prototypes. Declare new functions.
ld/
* emultempl/ppc64elf.em (build_toc_list): Report errors from
ppc64_elf_next_toc_section.
(after_allocation): Update for changed function names and params.
Run second pass of multitoc partitioning.
PR 5604
* elf-bfd.h (struct elf_backend_data): Add gc_keep. Remove param
names from others.
(_bfd_elf_gc_keep): Declare.
* elfxx-target.h (elf_backend_gc_keep): Define.
(elfNN_bed): Init new field.
* elflink.c (_bfd_elf_gc_keep): New function.
(bfd_elf_gc_sections): Call gc_keep.
* elf64-ppc.c (elf_backend_gc_keep): Define.
(struct _ppc64_elf_section_data): Move .opd related fields to
a struct so they don't occupy the same storage. Adjust accesses
throughout file.
(ppc64_elf_gc_keep): New function, split out from..
(ppc64_elf_gc_mark_hook): ..here. Don't call _bfd_elf_gc_mark
to mark .opd section, just set gc_mark.
(ppc64_elf_edit_opd): Remove no_opd_opt parm. Don't set opd->adjust
unless we are changing .opd. Test non-NULL opd->adjust at all
accesses throughout file.
* elf64-ppc.h (ppc64_elf_edit_opd): Update prototype.
ld/
PR 5604
* ldlang.c (lang_gc_sections): Move code to set SEC_KEEP on entry
syms to _bfd_elf_gc_keep.
* emultempl/ppc64elf.em (ppc_before_allocation): Don't call
ppc64_elf_edit_opd if no_opd_opt.
* elf-bfd.h (_bfd_elf_gc_mark): Declare.
* elflink.c (elf_link_input_bfd): Formatting.
(_bfd_elf_gc_mark): Rename from elf_gc_mark and make global. Adjust
all callers.
* elf64-ppc.c (struct ppc_link_hash_entry): Remove is_entry.
(link_hash_newfunc): Don't set it.
(ppc64_elf_copy_indirect_symbol): Nor copy it.
(ppc64_elf_mark_entry_syms): Delete.
(ppc64_elf_gc_mark_hook): Mark entry syms here. Also mark opd
sections. Use get_opd_info.
* elf64-ppc.h (ppc64_elf_mark_entry_syms): Delete.
ld/
* emultempl/ppc64elf.em (ppc_after_open): Delete.
(LDEMUL_AFTER_OPEN): Don't define.
(ppc64_elf_next_input_section): Use it here to set has_gp_reloc.
Return error condition.
(ppc64_elf_size_stubs): Restrict toc adjusting stubs to sections
that have has_gp_reloc set.
(struct ppc_link_hash_table): Add stub_count.
(ppc_build_one_stub): Increment it.
(ppc64_elf_link_hash_table_create): zmalloc rather than clearing
individual fields.
* elf64-ppc.h (ppc64_elf_next_input_section): Update prototype.
(TLS_GD): ..define this instead and update all uses.
(TLS_TPRELGD): Define.
(ppc64_elf_link_hash_table_create): Tweak initialization of
init_refcount and init_offset.
(ppc64_elf_check_relocs): Add one extra element to t_symndx array.
Mark second slot of GD or LD toc entries.
(get_tls_type): Return an int. Distinguish toc GD and LD entries
from other tls types.
(ppc64_elf_tls_setup): New function, split out from..
(ppc64_elf_tls_optimize): ..here. Don't optimize when symbols are
defined in a dynamic object. Fix LD optimization. Don't set TLS_TPREL
on GD->IE optimization, use TLS_TPRELGD instead. Use get_tls_type
return value to properly decide whether toc GD and LD entries can
optimize away __tls_get_addr call. Check next reloc after DTPMOD64
to determine GD or LD rather than looking at TLS_LD flag. Don't
attempt to adjust got entry tls_type here..
(allocate_dynrelocs): ..instead, adjust got entry tls_type here, and
look for possible merges.
(ppc64_elf_size_dynamic_sections): Adjust local got entries for
optimization.
(ppc64_elf_size_stubs): Tweak __tls_get_addr fudge.
(ppc64_elf_relocate_section): Rename some vars to better reflect usage.
Make use of return value from get_tls_type to properly detect GD and
LD optimizations. Split tlsld/gd hi/ha from lo/ds case. Don't
handle tls_get_addr removal when looking at REL24 relocs, do it when
looking at the previous reloc. Check reloc after DTPMOD64 to determine
GD or LD.
* elf64-ppc.h (ppc64_elf_tls_setup): Declare.
* libbfd.h: Regenerate.
* bfd-in2.h: Regenerate.
* elf64-ppc.c (TP_OFFSET, DTP_OFFSET): Declare.
(ppc64_elf_howto_raw): Add TLS howto's. Adjust R_PPC64_NONE to be
against a 32 bit field.
(ppc64_elf_reloc_type_lookup): Handle TLS relocs.
(_ppc64_elf_section_data): Add t_symndx and comments.
(ppc64_elf_section_data): Use elf_section_data macro.
(ppc64_elf_new_section_hook): American spelling.
(struct got_entry, struct plt_entry): New.
(MUST_BE_DYN_RELOC): Rename from IS_ABSOLUTE_RELOC.
(struct ppc_stub_hash_entry): Add "addend" field.
(struct ppc_link_hash_entry): Add "tls_type".
(TLS_TLS, TLS_GD_LD, TLS_LD, TLS_TPREL, TLS_DTPREL,
TLS_EXPLICIT): Define.
(struct ppc_link_hash_table): Add tls_sec, tls_get_addr, tlsld_got.
(link_hash_newfunc): Init new fields.
(ppc64_elf_link_hash_table_create): Likewise. Set init_relcount and
init_offset to NULL.
(ppc64_elf_copy_indirect_symbol): Copy got and plt info. Don't call
_bfd_elf_link_hash_copy_indirect, rather insert relevant code from
there.
(update_local_sym_info, update_plt_info): New functions.
(ppc64_elf_check_relocs): Use them. Handle TLS relocs. Adjust GOT
handling to use got.glist rather than got.refcount. Likewise for PLT.
(ppc64_elf_gc_sweep_hook): Handle TLS relocs, new GOT and PLT lists.
(func_desc_adjust): Adjust for new PLT list.
(ppc64_elf_adjust_dynamic_symbol): Likewise.
(get_sym_h, get_tls_type): New functions.
(ppc64_elf_edit_opd): Remove unused variable. Use get_sym_h.
(ppc64_elf_tls_optimize): New function.
(allocate_dynrelocs): Adjust for new PLT and GOT lists. Allocate
TLS relocs.
(ppc64_elf_size_dynamic_sections): Likewise.
(ppc_type_of_stub): Adjust for new PLT list.
(ppc_build_one_stub): Likewise.
(ppc64_elf_size_stubs): Likewise. Use get_sym_h. Treat __tls_get_addr
calls specially.
(ppc64_elf_relocate_section): Adjust for new GOT and PLT lists. Handle
TLS relocs. Report local syms using bfd_elf_local_sym_name. Don't
init GOT entries that have a reloc. Generate GOT relocs here..
(ppc64_elf_finish_dynamic_symbol): ..not here. Adjust for PLT list.
* elf64-ppc.h (ppc64_elf_tls_optimize): Declare.
relocatable link too.
(elf_link_input_bfd): When emitting relocs, adjust offsets for
eh_frame and stab sections. Zap deleted relocs.
(elf_reloc_symbol_deleted_p): Return true for zero r_symndx.
(elf_bfd_discard_info): Run for relocatable link too.
* elf64-ppc.c (ppc64_elf_edit_opd): Rename from edit_opd. Make global.
Handle ld -r case.
(ppc64_elf_size_dynamic_sections): Don't call edit_opd from here.
* elf64-ppc.h (ppc64_elf_edit_opd): Declare.
(ppc64_elf_ha_reloc): New function.
(ppc64_elf_brtaken_reloc): New function.
(ppc64_elf_sectoff_reloc): New function.
(ppc64_elf_sectoff_ha_reloc): New function.
(ppc64_elf_toc_reloc): New function.
(ppc64_elf_toc_ha_reloc): New function.
(ppc64_elf_toc64_reloc): New function.
(ppc64_elf_unhandled_reloc): New function.
(ppc64_elf_howto_raw): Use the above.
<R_PPC64_RELATIVE>: Mark pc_relative, pcrel_offset.
<R_PPC64_SECTOFF>: Not pc_relative or pcrel_offset. Fix dst_mask.
<R_PPC64_SECTOFF_DS>: Likewise.
(IS_ABSOLUTE_RELOC): Update.
(struct ppc_link_hash_table): Add have_undefweak.
(ppc64_elf_link_hash_table_create): Init.
(func_desc_adjust): Set have_undefweak.
(ppc64_elf_func_desc_adjust): Call func_desc_adjust earlier. Only
add the .sfpr blr when have_undefweak.
(ppc64_elf_setup_section_lists): Check hash table flavour.
(ppc64_elf_next_input_section): Move output_section->owner test to
ppc64elf.em.
(ppc64_elf_set_toc): Rename to ppc64_elf_toc, remove info param
and relocatable test. Return TOCstart and don't set elf_gp.
(ppc64_elf_relocate_section): Correct BRTAKEN/BRNTAKEN branch
offset calculation. Add assert on weak sym branch tweaks.
* elf64-ppc.h (ppc64_elf_set_toc): Delete.
(ppc64_elf_toc): Declare.
(ppc64_elf_next_input_section): Update.
* emultempl/ppc64elf.em (gld${EMULATION_NAME}_after_allocation):
Adjust for ppc64_elf_set_toc change. #include libbfd.h.
(build_section_lists): Do output_section tests here.
(ppc64_elf_relocate_section): Use them. Don't look for plt calls
on R_PPC64_ADDR24 relocs. Require a nop or no link reg on plt
call branches. Correct undefined weak destination.
(ppc64_elf_func_desc_adjust): Always create at least one blr in
.sfpr, and correct case where either only savef* or restf* is
needed.
Long branch stubs, multiple stub sections.
* elf64-ppc.h (ppc64_elf_setup_section_lists): Declare.
(ppc64_elf_next_input_section): Declare.
* elf64-ppc.c: Move linker-only prototypes.
(STUB_SUFFIX): Define.
(enum ppc_stub_type): New.
(struct ppc_stub_hash_entry): New.
(struct ppc_branch_hash_entry): New.
(struct ppc_link_hash_entry): Add stub_cache, oh.
(struct ppc_link_hash_table): Add stub_hash_table etc. Remove
sstub. Add sbrlt, srelbrlt, has_14bit_branch, stub_iteration.
Rename plt_overflow to stub_error.
(ppc_stub_hash_lookup): Define.
(ppc_branch_hash_lookup): Define.
(stub_hash_newfunc): New function.
(branch_hash_newfunc): New function.
(link_hash_newfunc): Init new fields.
(ppc64_elf_link_hash_table_create): Likewise.
(ppc64_elf_link_hash_table_free): New function.
(ppc_stub_name): New function.
(ppc_get_stub_entry): New function.
(ppc_add_stub): New function.
(create_linkage_sections): Use bfd_make_section_anyway. Create
.branch_lt and .rela.branch_lt sections. Don't create .stub.
(ppc64_elf_check_relocs): Set has_14bit_branch on R_PPC64_REL14*,
and set up for plt call stubs. Link func and func desc syms.
(ppc64_elf_gc_sweep_hook): Handle REL14* as per REL24.
(func_desc_adjust): Avoid hash lookup when func desc sym available
via shortcut, and set links when processing.
(ppc64_elf_hide_symbol): Likewise.
(allocate_dynrelocs): Don't allocate stub section here.
(ppc64_elf_size_dynamic_sections): Handle sbrlt and srelbrlt.
Remove sstub code.
(ppc_type_of_stub): New function.
(build_one_stub): Delete.
(ppc_build_one_stub): New function.
(ppc_size_one_stub): New function.
(ppc64_elf_setup_section_lists): New function.
(ppc64_elf_next_input_section): New function.
(group_sections): New function.
(get_local_syms): New function.
(ppc64_elf_size_stubs): Rewrite.
(ppc64_elf_build_stubs): Rewrite.
(ppc64_elf_relocate_section): Look up stub entry for REL24
relocs. Don't propagate REL14* to dynamic objects. Look for long
branch stubs if REL14* or REL24 relocs won't reach.
(bfd_elf64_bfd_link_hash_table_free): Define.
