#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
#define wmb() __asm__ __volatile__ ("sync" : : : "memory")
-#ifdef __SUBARCH_HAS_LWSYNC
+/* The sub-arch has lwsync */
+#if defined(__powerpc64__) || defined(CONFIG_PPC_E500MC)
# define SMPWMB LWSYNC
#else
# define SMPWMB eieio
#define smp_mb__before_spinlock() smp_mb()
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * Prevent execution of subsequent instructions until preceding branches have
+ * been fully resolved and are no longer executing speculatively.
+ */
+#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; nop
+
+// This also acts as a compiler barrier due to the memory clobber.
+#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
+
+#else /* !CONFIG_PPC_BOOK3S_64 */
+#define barrier_nospec_asm
+#define barrier_nospec()
+#endif
+
#include <asm-generic/barrier.h>
#endif /* _ASM_POWERPC_BARRIER_H */