1  //===-- sanitizer_ptrauth.h -------------------------------------*- C++ -*-===//
       2  //
       3  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
       4  // See https://llvm.org/LICENSE.txt for license information.
       5  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
       6  //
       7  //===----------------------------------------------------------------------===//
       8  
       9  #ifndef SANITIZER_PTRAUTH_H
      10  #define SANITIZER_PTRAUTH_H
      11  
      12  #if __has_feature(ptrauth_calls)
      13  #include <ptrauth.h>
      14  #elif defined(__ARM_FEATURE_PAC_DEFAULT) && !defined(__APPLE__)
      15  inline unsigned long ptrauth_strip(void* __value, unsigned int __key) {
      16    // On the stack the link register is protected with Pointer
      17    // Authentication Code when compiled with -mbranch-protection.
      18    // Let's stripping the PAC unconditionally because xpaclri is in
      19    // the NOP space so will do nothing when it is not enabled or not available.
      20    unsigned long ret;
      21    asm volatile(
      22        "mov x30, %1\n\t"
      23        "hint #7\n\t"  // xpaclri
      24        "mov %0, x30\n\t"
      25        : "=r"(ret)
      26        : "r"(__value)
      27        : "x30");
      28    return ret;
      29  }
      30  #define ptrauth_auth_data(__value, __old_key, __old_data) __value
      31  #define ptrauth_string_discriminator(__string) ((int)0)
      32  #else
      33  // Copied from <ptrauth.h>
      34  #define ptrauth_strip(__value, __key) __value
      35  #define ptrauth_auth_data(__value, __old_key, __old_data) __value
      36  #define ptrauth_string_discriminator(__string) ((int)0)
      37  #endif
      38  
      39  #define STRIP_PAC_PC(pc) ((uptr)ptrauth_strip(pc, 0))
      40  
      41  #endif // SANITIZER_PTRAUTH_H