/* * Copyright (c) Meta Platforms, Inc. and affiliates. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <folly/portability/SysMembarrier.h> #include <cassert> #include <cerrno> #include <folly/Portability.h> #include <folly/portability/SysSyscall.h> namespace folly { namespace detail { namespace { constexpr long linux_syscall_nr_(long nr, long def) { … } // __NR_membarrier or -1; always defined as v.s. __NR_membarrier #if defined(__NR_membarrier) constexpr long linux_syscall_nr_membarrier_ = __NR_membarrier; #else constexpr long linux_syscall_nr_membarrier_ = …; #endif #if defined(__aarch64__) constexpr long def_linux_syscall_nr_membarrier_ = …; #elif defined(__x86_64__) || defined(_M_X64) constexpr long def_linux_syscall_nr_membarrier_ = 324; #else constexpr long def_linux_syscall_nr_membarrier_ = -1; #endif // __NR_membarrier with hardcoded fallback where available or -1 constexpr long linux_syscall_nr_membarrier = …; // linux_membarrier_cmd // // Backport from the linux header, since older versions of the header may // define the enum but not all of the enum constants that we require. // // mimic: membarrier_cmd, linux/membarrier.h enum linux_membarrier_cmd { … }; FOLLY_ERASE int call_membarrier(int cmd, unsigned int flags = 0) { … } } // namespace bool sysMembarrierPrivateExpeditedAvailable() { … } int sysMembarrierPrivateExpedited() { … } } // namespace detail } // namespace folly