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__)
15inline 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
42