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_intrinsics)
13#  include <ptrauth.h>
14#elif defined(__ARM_FEATURE_PAC_DEFAULT) && !defined(__APPLE__)
15// On the stack the link register is protected with Pointer
16// Authentication Code when compiled with -mbranch-protection.
17// Let's stripping the PAC unconditionally because xpaclri is in
18// the NOP space so will do nothing when it is not enabled or not available.
19#  define ptrauth_strip(__value, __key) \
20    ({                                  \
21      __typeof(__value) ret;            \
22      asm volatile(                     \
23          "mov x30, %1\n\t"             \
24          "hint #7\n\t"                 \
25          "mov %0, x30\n\t"             \
26          "mov x30, xzr\n\t"            \
27          : "=r"(ret)                   \
28          : "r"(__value)                \
29          : "x30");                     \
30      ret;                              \
31    })
32#  define ptrauth_auth_data(__value, __old_key, __old_data) __value
33#  define ptrauth_string_discriminator(__string) ((int)0)
34#else
35// Copied from <ptrauth.h>
36#  define ptrauth_strip(__value, __key) __value
37#  define ptrauth_auth_data(__value, __old_key, __old_data) __value
38#  define ptrauth_string_discriminator(__string) ((int)0)
39#endif
40
41#define STRIP_PAC_PC(pc) ((uptr)ptrauth_strip(pc, 0))
42
43#endif // SANITIZER_PTRAUTH_H