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 #else 30 #error Please fill in barrier macros 31 #endif 32 33