compiler-rt/lib/sanitizer_common/sanitizer_ptrauth.h

   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