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author | Sam Tebbs <sam.tebbs@arm.com> | 2018-12-05 18:27:23 +0000 |
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committer | Thomas Preud'homme <thomas.preudhomme@linaro.org> | 2018-12-05 18:30:08 +0000 |
commit | 3a67e1a6b4430374f3073e51bb19347d4c421cfe (patch) | |
tree | 6a75b3b1a27561b0e395dc69889051b71e67eff5 /bfd | |
parent | 90af06793e9d391c0aa33994f21bba6971d084f7 (diff) | |
download | gdb-3a67e1a6b4430374f3073e51bb19347d4c421cfe.zip gdb-3a67e1a6b4430374f3073e51bb19347d4c421cfe.tar.gz gdb-3a67e1a6b4430374f3073e51bb19347d4c421cfe.tar.bz2 |
[aarch64] Add support for pointer authentication B key
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.
Diffstat (limited to 'bfd')
-rw-r--r-- | bfd/ChangeLog | 4 | ||||
-rw-r--r-- | bfd/elf-eh-frame.c | 2 |
2 files changed, 6 insertions, 0 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 618126f..de468a4 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,7 @@ +2018-12-05 Sam Tebbs <sam.tebbs@arm.com> + + * elf-eh-frame.c (_bfd_elf_parse_eh_frame): Add check for 'B'. + 2018-12-04 H.J. Lu <hongjiu.lu@intel.com> PR ld/23372 diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c index 12f06ef..b76a657 100644 --- a/bfd/elf-eh-frame.c +++ b/bfd/elf-eh-frame.c @@ -797,6 +797,8 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info, while (*aug != '\0') switch (*aug++) { + case 'B': + break; case 'L': REQUIRE (read_byte (&buf, end, &cie->lsda_encoding)); ENSURE_NO_RELOCS (buf); |