/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ /* Copyright (c) 2019 Facebook */ #ifndef __LIBBPF_LIBBPF_UTIL_H #define __LIBBPF_LIBBPF_UTIL_H #include <stdbool.h> #ifdef __cplusplus extern "C" { #endif /* Use these barrier functions instead of smp_[rw]mb() when they are * used in a libbpf header file. That way they can be built into the * application that uses libbpf. */ #if defined(__i386__) || defined(__x86_64__) # define libbpf_smp_rmb() asm volatile("" : : : "memory") # define libbpf_smp_wmb() asm volatile("" : : : "memory") # define libbpf_smp_mb() \ asm volatile("lock; addl $0,-4(%%rsp)" : : : "memory", "cc") /* Hinders stores to be observed before older loads. */ # define libbpf_smp_rwmb() asm volatile("" : : : "memory") #elif defined(__aarch64__) # define libbpf_smp_rmb() asm volatile("dmb ishld" : : : "memory") # define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") # define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") # define libbpf_smp_rwmb() libbpf_smp_mb() #elif defined(__arm__) /* These are only valid for armv7 and above */ # define libbpf_smp_rmb() asm volatile("dmb ish" : : : "memory") # define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") # define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") # define libbpf_smp_rwmb() libbpf_smp_mb() #else /* Architecture missing native barrier functions. */ # define libbpf_smp_rmb() __sync_synchronize() # define libbpf_smp_wmb() __sync_synchronize() # define libbpf_smp_mb() __sync_synchronize() # define libbpf_smp_rwmb() __sync_synchronize() #endif #ifdef __cplusplus } /* extern "C" */ #endif #endif