#if defined(__i386__) || defined(__x86_64__)
#define barrier() asm volatile("" ::: "memory")
-#define mb() __sync_synchronize()
-
-#define smp_mb() mb()
-# define dma_rmb() barrier()
-# define dma_wmb() barrier()
-# define smp_rmb() barrier()
-# define smp_wmb() barrier()
+#define virt_mb() __sync_synchronize()
+#define virt_rmb() barrier()
+#define virt_wmb() barrier()
+/* Atomic store should be enough, but gcc generates worse code in that case. */
+#define virt_store_mb(var, value) do { \
+ typeof(var) virt_store_mb_value = (value); \
+ __atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \
+ __ATOMIC_SEQ_CST); \
+ barrier(); \
+} while (0);
/* Weak barriers should be used. If not - it's a bug */
-# define rmb() abort()
-# define wmb() abort()
+# define mb() abort()
+# define rmb() abort()
+# define wmb() abort()
#else
#error Please fill in barrier macros
#endif
--- /dev/null
+#ifndef LINUX_COMPILER_H
+#define LINUX_COMPILER_H
+
+#define WRITE_ONCE(var, val) \
+ (*((volatile typeof(val) *)(&(var))) = (val))
+
+#define READ_ONCE(var) (*((volatile typeof(val) *)(&(var))))
+
+#endif