pauth_linux_aarch64.inline.hpp

/*
 * Copyright (c) 2021, Arm Limited. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */

#ifndef OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP
#define OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP

// Only the PAC instructions in the NOP space can be used. This ensures the
// binaries work on systems without PAC. Write these instructions using their
// alternate "hint" instructions to ensure older compilers can still be used.

#define XPACLRI "hint #0x7;"

inline address pauth_strip_pointer(address ptr) {
  register address result __asm__("x30") = ptr;
  asm (XPACLRI : "+r"(result));
  return result;
}

#undef XPACLRI

#endif // OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP