1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #if defined(__i386__) || defined(__x86_64__) 3 #define barrier() asm volatile("" ::: "memory") 4 #define virt_mb() __sync_synchronize() 5 #define virt_rmb() barrier() 6 #define virt_wmb() barrier() 7 /* Atomic store should be enough, but gcc generates worse code in that case. */ 8 #define virt_store_mb(var, value) do { \ 9 typeof(var) virt_store_mb_value = (value); \ 10 __atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \ 11 __ATOMIC_SEQ_CST); \ 12 barrier(); \ 13 } while (0); 14 /* Weak barriers should be used. If not - it's a bug */ 15 # define mb() abort() 16 # define rmb() abort() 17 # define wmb() abort() 18 #else 19 #error Please fill in barrier macros 20 #endif 21 22