Index: libunwind/src/DwarfInstructions.hpp =================================================================== --- libunwind/src/DwarfInstructions.hpp +++ libunwind/src/DwarfInstructions.hpp @@ -72,6 +72,10 @@ assert(0 && "getCFA(): unknown location"); __builtin_unreachable(); } +#if defined(_LIBUNWIND_TARGET_AARCH64) + static bool getRA_SIGN_STATE(A &addressSpace, R registers, pint_t cfa, + PrologInfo &prolog); +#endif }; template @@ -166,6 +170,21 @@ } _LIBUNWIND_ABORT("unsupported restore location for vector register"); } +#if defined(_LIBUNWIND_TARGET_AARCH64) +template +bool DwarfInstructions::getRA_SIGN_STATE(A &addressSpace, R registers, + pint_t cfa, PrologInfo &prolog) { + pint_t ra_sign_state; + auto regloc = prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE]; + if (regloc.location == CFI_Parser::kRegisterUnused) + ra_sign_state = regloc.value; + else + ra_sign_state = getSavedRegister(addressSpace, registers, cfa, regloc); + + // Only bit[0] is meaningful. + return ra_sign_state & 0x01; +} +#endif template int DwarfInstructions::stepWithDwarf(A &addressSpace, pint_t pc, @@ -235,7 +254,7 @@ // restored. autia1716 is used instead of autia as autia1716 assembles // to a NOP on pre-v8.3a architectures. if ((R::getArch() == REGISTERS_ARM64) && - prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE].value && + getRA_SIGN_STATE(addressSpace, registers, cfa, prolog) && returnAddress != 0) { #if !defined(_LIBUNWIND_IS_NATIVE_ONLY) return UNW_ECROSSRASIGNING; Index: libunwind/test/aarch64.ra_sign_state.pass.cpp =================================================================== --- /dev/null +++ libunwind/test/aarch64.ra_sign_state.pass.cpp @@ -0,0 +1,58 @@ +// -*- C++ -*- +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// REQUIRES: linux && target={{aarch64-.+}} + +#include + +__attribute__((noinline, target("branch-protection=pac-ret+leaf"))) +void bar(void) { + throw 1; +} + +__attribute__((noinline, target("branch-protection=none"))) +void foo(void) { + // Insted of .cfi_negate_ra_state the RA_SIGN_STATE pseudo register could be + // set directly set by a dwarf expression but the two can't be mixed. + asm volatile( + ".cfi_escape 0x16," //DW_CFA_val_expression + "34," //REG_34(RA_SIGN_STATE) + "1," //expression_length(1) + "0x31\n" //DW_OP_lit1 + "add sp, sp, 16\n" // Restore SP's value before the stack frame is + // created. + "paciasp\n" // Sign the LR. + "str lr, [sp, -0x8]\n" // Overwrite on the stack. + "mov sp, x29\n" // Re-Restore lr from fp. + ); + bar(); + _Exit(-1); +} + +__attribute__((noinline, target("branch-protection=pac-ret"))) +void bazz(void) { + // ".cfi_negate_ra_state" is emitted by the compiler. + try { + foo(); + } catch (int i) { + if (i == 1) + throw i; + throw 2; + } +} + +int main(int, char **) { + try { + bazz(); + } catch (int i) { + if (i == 1) + _Exit(0); + } + return -1; +}