gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/vdso/barrier.h (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  #ifndef VDSO_BARRIER_H_
    16  #define VDSO_BARRIER_H_
    17  
    18  namespace vdso {
    19  
    20  // Compiler Optimization barrier.
    21  inline void barrier(void) { __asm__ __volatile__("" ::: "memory"); }
    22  
    23  #if __x86_64__
    24  
    25  inline void memory_barrier(void) {
    26    __asm__ __volatile__("mfence" ::: "memory");
    27  }
    28  inline void read_barrier(void) { barrier(); }
    29  inline void write_barrier(void) { barrier(); }
    30  
    31  #elif __aarch64__
    32  
    33  inline void memory_barrier(void) {
    34    __asm__ __volatile__("dmb ish" ::: "memory");
    35  }
    36  inline void read_barrier(void) {
    37    __asm__ __volatile__("dmb ishld" ::: "memory");
    38  }
    39  inline void write_barrier(void) {
    40    __asm__ __volatile__("dmb ishst" ::: "memory");
    41  }
    42  
    43  #else
    44  #error "unsupported architecture"
    45  #endif
    46  
    47  }  // namespace vdso
    48  
    49  #endif  // VDSO_BARRIER_H_