Armv8.3-A has another key used in pointer authentication called the
B-key (other than the A-key that is already supported). In order for
stack unwinders to work it is necessary to be able to identify frames
that have been signed with the B-key rather than the A-key and it was
felt that keeping this as an augmentation character in the CIE was the
best bet. The DWARF extensions for ARM therefore propose to add a new
augmentation character 'B' to the CIE augmentation string and the
corresponding cfi directive ".cfi_b_key_frame". I've made the relevant
changes to GAS and LD to add support for B-key unwinding, which required
modifying LD to check for 'B' in the augmentation string, adding the
".cfi_b_key_frame" directive to GAS and adding a "pauth_key" field to
GAS's fde_entry and cie_entry structs.
The pointer authentication instructions will behave as NOPs on
architectures that don't support them, and so a check for the
architecture being assembled for is not necessary since there will be no
behavioural difference between augmentation strings with and without the
'B' character on such architectures.
2018-12-05 Sam Tebbs <sam.tebbs@arm.com>
bfd/
* elf-eh-frame.c (_bfd_elf_parse_eh_frame): Add check for 'B'.
gas/
* dw2gencfi.c (struct cie_entry): Add tc_cie_entry_extras invocation.
(alloc_fde_entry): Add tc_fde_entry_init_extra invocation.
(output_cie): Add tc_output_cie_extra invocation.
(select_cie_for_fde): Add tc_cie_fde_equivalent_extra and
tc_cie_entry_init_extra invocation.
(frch_cfi_data, cfa_save_data): Move to dwgencfi.h.
* config/tc-aarch64.c (s_aarch64_cfi_b_key_frame): Declare.
(md_pseudo_table): Add "cfi_b_key_frame".
* config/tc-aarch64.h (tc_fde_entry_extras, tc_cie_entry_extras,
tc_fde_entry_init_extra, tc_output_cie_extra,
tc_cie_fde_equivalent_extra, tc_cie_entry_init_extra): Define.
* dw2gencfi.h (struct fde_entry): Add tc_fde_entry_extras invocation.
(pointer_auth_key): Define.
(frch_cfi_data, cfa_save_data): Move from dwgencfi.c.
* doc/c-aarch64.texi (.cfi_b_key_frame): Add documentation.
* testsuite/gas/aarch64/(pac_ab_key.d, pac_ab_key.s): New file.
Add asserts that reloc size matches encoding size, and tidy.
* dw2gencfi.c (encoding_size): Return unsigned int.
(emit_expr_encoded): Assert size matches reloc bitsize.
(output_fde): Use unsigned for offset_size and addr_size. Set
addr_size earlier and use in place of constant 4 and uses of
DWARF2_FDE_RELOC_SIZE. Assert it matches reloc bitsize.
The .cfi_sections directive can be safely used multiple times
with different sections named at any time unless the compact form
of exception handling is requested after CFI information has
been emitted. Only the compact form of CFI information changes
the way in which CFI is generated and therefore cannot be
retrospectively requested after generating CFI information.
gas/
PR gas/20648
* dw2gencfi.c (dot_cfi_sections): Refine the check for
inconsistent .cfi_sections to only consider compact vs non
compact forms.
* testsuite/gas/cfi/cfi-common-9.d: New file.
* testsuite/gas/cfi/cfi-common-9.s: New file.
* testsuite/gas/cfi/cfi.exp: Run new test.
This patch adds support for .cfi_val_offset GAS pseudo command which
maps to DW_CFA_val_offset and DW_CFA_val_offset_sf.
gas/ChangeLog:
2016-09-29 Andreas Krebbel <krebbel@linux.vnet.ibm.com>
* doc/as.texinfo: Add docu for .cfi_val_offset.
* dw2gencfi.c (cfi_add_CFA_val_offset): New function.
(dot_cfi): Add case for DW_CFA_val_offset.
(output_cfi_insn): Likewise.
(cfi_pseudo_table): Add entry for cfi_val_offset.
* dw2gencfi.h: Add prototype for cfi_add_CFA_val_offset.
* testsuite/gas/cfi/cfi-common-8.d: New test.
* testsuite/gas/cfi/cfi-common-8.s: New test.
* testsuite/gas/cfi/cfi.exp: Run cfi-common-8 testcase.
binutils/ChangeLog:
2016-09-29 Andreas Krebbel <krebbel@linux.vnet.ibm.com>
* dwarf.c (display_debug_frames): Adjust output line.
PR gas/19614
* dw2gencfi.c (cfi_sections_set): Delay setting this variable
until it is actually used.
(cfi_set_sections): Set cfi_sections_set to true.
(dot_cfi_startproc): Likewise.
(dot_cfi_endproc): Likewise.
(dot_cfi_fde_data): Likewise.
(cfi_finish): Likewise.
(dot_cfi_sections): Do not set cfi_sections_set.
* doc/as.texinfo (.cfi_sections): Note that targets can provide
their own cfi section name. Also note that the directive can be
reissued provided that CFI generation has not started.
* testsuite/gas/mips/compact-eh-err2.s: Add .cfi_startproc and
.cfi_endproc directives so that the redefinition of .cfi_sections
will trigger the generation of the error message.
* testsuite/gas/mips/compact-eh-err2.l: Update expected line
number of error message.
While actually starting to use that new directive, I noticed a few
oversights of the original commit.
gas/
2015-02-06 Jan Beulich <jbeulich@suse.com>
* dw2gencfi.c (select_cie_for_fde): Also bail on CFI_label.
(cfi_change_reg_numbers): Also do nothing for CFI_label.
(cfi_pseudo_table): Also handle .cfi_label when not supporting
CFI directives.
When runtime patching code (like e.g. done by the Linux kernel) there
may be cases where the set of stack frame alterations differs between
unpatched and patched code. Consequently the corresponding unwind data
needs patching too. Locating the right places within an FDE, however,
is rather cumbersome without a way to insert labels in the resulting
section. Hence this patch introduces a new directive, .cfi_label. Note
that with the way CFI data gets emitted currently (at the end of the
assembly process) this can't support local FB- and dollar-labels.
gas/
2015-01-12 Jan Beulich <jbeulich@suse.com>
* gas/dw2gencfi.c (cfi_add_label, dot_cfi_label): New.
(cfi_pseudo_table): Add "cfi_label".
(output_cfi_insn): Handle CFI_label.
(select_cie_for_fde): Als terminate CIE when encountering
CFI_label.
* dw2gencfi.h (cfi_add_label): Declare.
(struct cfi_insn_data): New member "sym_name".
(CFI_label): New.
* read.c (read_symbol_name): Drop "static".
* read.h (read_symbol_name): Declare.
gas/testsuite/
2015-01-12 Jan Beulich <jbeulich@suse.com>
gas/cfi/cfi-label.d, gas/cfi/cfi-label.s: New.
gas/cfi/cfi.exp: Run new tests.
* dw2gencfi.h (all_fde_data): Declare.
* config/tc-alpha.c (alpha_elf_md_end): Don't convert legacy unwind
info to cfi unwind info if the user already has supplied some.
Use throughout in place of #if SUPPORT_FRAME_LINKONCE.
(struct fde_entry): Rename cseg to cur_seg.
(cfi_change_reg_numbers): Remove ATTRIBUTE_UNUSED.
(get_cfi_seg): Likewise. Use if (SUPPORT_FRAME_LINKONCE) rather
that #if SUPPORT_FRAME_LINKONCE.
(cfi_finish): Likewise.
file to conditionally compile code added 2011-04-26.
(cfi_change_reg_numbers): Add ATTRIBUTE_UNUSED on params only used
when SUPPORT_FRAME_LINKONCE.
(get_cfi_seg): Likewise. Reintroduce old code for when not
SUPPORT_FRAME_LINKONCE.
(cfi_finish): Move get_cfi_seg calls out of loop when not
SUPPORT_FRAME_LINKONCE. Avoid unused var warning.
(dwcfi_hash): New static hash variable.
(get_debugseg_name): New.
(alloc_debugseg_item): New.
(make_debug_seg): New.
(dwcfi_hash_insert): New.
(dwcfi_hash_find): New.
(dwcfi_hash_find_or_make): New.
(cfi_insn_data): New member cur_seg.
(cie_entry): Likewise.
(fde_entry): New cseg and handled members.
(alloc_fde_entry): Initialize cseg member.
(alloc_cfi_insn_data): Initialize cur_seg member.
(dot_cfi_sections): Compare for beginning of
section names via strncmp.
(get_cfi_seg): New.
(cfi_finish): Treat link-once sections.
(is_now_linkonce_segment): New local helper.
(output_cie): Ignore cie entries not member of current
segment.
(output_fde): Likewise.
(select_cie_for_fde): Likewise.
(cfi_change_reg_numbers): Add new argument for current segment
and ignore insn elements, if not part of current segment.
* ehopt.c (get_cie_info): Use strncmp for
section name matching.
(heck_eh_frame): Likewise.
* coffcode.h (sec_to_styp_flags): Allow linkonce for
debugging sections.
* scripttempl/pe.sc: Handle .eh_frame($|.)* sections.
* scripttempl/pep.sc: Likewise.
* ld-pe/pe.exp: Add cfi/cfi32 tests.
* ld-pe/cfi.d: New.
* ld-pe/cfi32.d: New.
* ld-pe/cfia.s: New.
* ld-pe/cfib.s: New.
(output_fde): Use it. Make sure to fully init exp before using it.
testsuite/
* gas/cfi/cfi-common-1.d: Use objdump instead of readelf to dump.
* gas/cfi/cfi-common-2.d, gas/cfi/cfi-common-3.d,
gas/cfi/cfi-common-4.d, gas/cfi/cfi-common-6.d,
gas/cfi/cfi-common-7.d, gas/cfi/cfi-x86_64.d: Likewise.
* gas/cfi/cfi-x86_64.s: Remove .type directives.
* gas/cfi/cfi.exp: Run for pecoff objects too.
* gas/cfi/reloc-pe-i386.d, gas/cfi/reloc-pe-i386.s: New test.
* Makefile.in: Regenerated.
* ehopt.c: Include struc-symbol.h.
(check_eh_frame): For very small O_constant DW_CFA_advance_loc4
create correct DW_CFA_advance_loc. Handle O_subtract only
for code alignment factor 1, otherwise handle O_divide or
O_right_shift of O_subtract and O_constant.
(eh_frame_estimate_size_before_relax): Always divide by ca.
(eh_frame_convert_frag): Likewise.
* dw2gencfi.c (output_cfi_insn): Scale DW_CFA_advance_loc1,
DW_CFA_advance_loc2 and DW_CFA_advance_loc4 outputs.
(output_cie, output_fde): Use it.
(DWARF2_EH_FRAME_READ_ONLY): New.
(cfi_finish): Use it.
* config/tc-hppa.h (DWARF2_FDE_RELOC_SIZE): Set to 8 for 64-bit.
(DWARF2_CIE_DATA_ALIGNMENT): Change sign.
(DWARF2_EH_FRAME_READ_ONLY): New.
* config/tc-hppa.c (tc_gen_reloc): Generate pc-relative relocations
from the results of DIFF_EXPR_OK manipulation.
2008-02-13 Jan Beulich <jbeulich@novell.com>
* config/tc-i386.c (allow_pseudo_reg): New.
(parse_real_register): Check for NULL just once. Allow all
register table entries when allow_pseudo_reg is non-zero.
Don't allow any registers without type when allow_pseudo_reg
is zero.
(tc_x86_regname_to_dw2regnum): Replace with ...
(tc_x86_parse_to_dw2regnum): ... this.
(tc_x86_frame_initial_instructions): Adjust for above change.
* config/tc-i386.h (tc_regname_to_dw2regnum): Remove.
(tc_parse_to_dw2regnum): New.
(tc_x86_regname_to_dw2regnum): Replace with ...
(tc_x86_parse_to_dw2regnum): ... this.
* dw2gencfi.c (tc_parse_to_dw2regnum): New, broken out of ...
(cfi_parse_reg): ... this. Use tc_parse_to_dw2regnum. Adjust
error handling.
gas/testsuite/
2008-02-13 Jan Beulich <jbeulich@novell.com>
* gas/cfi/cfi-i386.s: Add code testing use of all registers.
Fix a few comments.
* gas/cfi/cfi-x86_64.s: Likewise.
* gas/cfi/cfi-i386.d, gas/cfi/cfi-x86_64.d: Adjust.
opcodes/
2008-02-13 Jan Beulich <jbeulich@novell.com>
* i386-gen.c (process_i386_registers): Process new fields.
* i386-opc.h (reg_entry): Shrink reg_flags and reg_num to
unsigned char. Add dw2_regnum and Dw2Inval.
* i386-reg.tbl: Provide initializers for dw2_regnum. Add pseudo
register names.
* i386-tbl.h: Re-generate.
personality and lsda.
(struct cie_entry): Add per_encoding, lsda_encoding and personality.
(alloc_fde_entry): Initialize per_encoding and lsda_encoding.
(cfi_pseudo_table): Handle .cfi_personality and .cfi_lsda.
(dot_cfi_personality, dot_cfi_lsda, encoding_size): New functions.
(output_cie): Output personality including its encoding and LSDA encoding.
(output_fde): Output LSDA.
(select_cie_for_fde): Don't share CIE if personality, its encoding or
LSDA encoding are different. Copy the 3 fields from fde_entry to
cie_entry.
* doc/as.texinfo (.cfi_personality, .cfi_lsda): Document.
* gas/cfi/cfi-common-6.d: New test.
* gas/cfi/cfi-common-6.s: New.
* gas/cfi/cfi.exp: Add cfi-common-6 test.
