commit 6835d019b22a4b643189d4ace2f8cae375ce89e5
author Tamas Petz <tamas.petz@arm.com> Wed Jan 22 14:22:41 2020 +0100
committer Elliott Hughes <enh@google.com> Tue Jul 14 13:31:59 2020 -0700
tree f74b0068e4b55e61d0f0d48952efb8fd26d0495b
parent 7ca7680ec579ecc9bff2237edc2148db606cc6a7

libunwindstack: support for Armv8.3-A Pointer Authentication

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

libunwindstack/tests/VerifyBionicTerminationTest.cpp

diff --git a/libunwindstack/tests/VerifyBionicTerminationTest.cpp b/libunwindstack/tests/VerifyBionicTerminationTest.cpp
index 6a3e91a..eb2b01d 100644
--- a/libunwindstack/tests/VerifyBionicTerminationTest.cpp
+++ b/libunwindstack/tests/VerifyBionicTerminationTest.cpp
@@ -55,7 +55,7 @@
     return DWARF_LOCATION_INVALID;
   }
   dwarf_loc_regs_t regs;
-  if (!section->GetCfaLocationInfo(rel_pc, fde, &regs)) {
+  if (!section->GetCfaLocationInfo(rel_pc, fde, &regs, ARCH_UNKNOWN)) {
     return DWARF_LOCATION_INVALID;
   }