33 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#include <stdlib.h>3#if defined(__i386__) || defined(__x86_64__)4#define barrier() asm volatile("" ::: "memory")5#define virt_mb() __sync_synchronize()6#define virt_rmb() barrier()7#define virt_wmb() barrier()8/* Atomic store should be enough, but gcc generates worse code in that case. */9#define virt_store_mb(var, value) do { \10 typeof(var) virt_store_mb_value = (value); \11 __atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \12 __ATOMIC_SEQ_CST); \13 barrier(); \14} while (0);15/* Weak barriers should be used. If not - it's a bug */16# define mb() abort()17# define dma_rmb() abort()18# define dma_wmb() abort()19#elif defined(__aarch64__)20#define dmb(opt) asm volatile("dmb " #opt : : : "memory")21#define virt_mb() __sync_synchronize()22#define virt_rmb() dmb(ishld)23#define virt_wmb() dmb(ishst)24#define virt_store_mb(var, value) do { WRITE_ONCE(var, value); dmb(ish); } while (0)25/* Weak barriers should be used. If not - it's a bug */26# define mb() abort()27# define dma_rmb() abort()28# define dma_wmb() abort()29#else30#error Please fill in barrier macros31#endif32 33