This patch adds support for handling return addresses signed with
pointer authentication. It simply strips the authentication code
without verifying its correctness, and thus works with both A and B
keys and through key-change boundaries.
Additons:
* DW_CFA_AARCH64_negate_ra_state: new CFA operation.
* RA_SIGN_STATE: new pseudo register.
* Pass the arch to DwarfCfa so that the new op is only executed
on aarch64.
The stripping uses the xpaclri instruction. This is a hint space
instruction which is compatible with pre Armv8.3-A devices. For cases
where it cannot be used, a mask can be set instead.
Test: libunwindstack_test
Without this patch all UnwindTest.* testcases should fail if
compiled with Pointer Authentication.
The tests should be executed with both -mbranch-protection=pac-ret and
pac-ret+leaf flags so that either some or all functions have pointer
authentication instructions.
Change-Id: Id7c3f1d0e2fc7fccb19bd1430826264405a9df7c
Add a specific test that __libc_init is the last frame in a stack
when run on device. In addition, it verifies that the return address
register is marked as undefined given the unwind.
Bug: 140008396
Test: New unit test passes on arm/arm64 (taimen device).
Test: New unit test passes on x86 (cuttlefish).
Test: New unit test passes on x86_64 (modified bionic/tests/run-on-host.sh)
Change-Id: Iefc151a7dbf52ab083c2bb78bad3d38b4e9e1254
