[Bug target/94514] aarch64: unwinding across mixed pac-ret and non-pac-ret frames is broken

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94514

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Szabolcs Nagy <nsz@gcc.gnu.org>:

https://gcc.gnu.org/g:6173489dbfe5828b2c4082d7a450a766779f87c7

commit r9-8592-g6173489dbfe5828b2c4082d7a450a766779f87c7
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Fri Apr 3 09:35:41 2020 +0000

    aarch64, libgcc: Fix unwinding from pac-ret to normal frames [PR94514]

    With -mbranch-protection=pac-ret the debug info toggles the
    signedness state of the return address so the unwinder knows when
    the return address needs pointer authentication.

    The unwind context flags were not updated according to the dwarf
    frame info.

    This causes unwinding across frames that were built without pac-ret
    to incorrectly authenticate the return address wich corrupts the
    return address on a system where PAuth is enabled.

    Note: This even affects systems where all code use pac-ret because
    unwinding across a signal frame the return address is not signed.

    gcc/testsuite/ChangeLog:

            Backport from mainline.
            2020-04-23  Szabolcs Nagy  <szabolcs.nagy@arm.com>

            PR target/94514
            * g++.target/aarch64/pr94514.C: Require lp64.
            * gcc.target/aarch64/pr94514.c: Likewise.

            Backport from mainline.
            2020-04-21  Szabolcs Nagy  <szabolcs.nagy@arm.com>

            PR target/94514
            * g++.target/aarch64/pr94514.C: New test.
            * gcc.target/aarch64/pr94514.c: New test.

    libgcc/ChangeLog:

            Backport from mainline.
            2020-04-21  Szabolcs Nagy  <szabolcs.nagy@arm.com>

            PR target/94514
            * config/aarch64/aarch64-unwind.h (aarch64_frob_update_context):
            Update context->flags accroding to the frame state.