diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 1e5df3ccdd5c..a1ee1a760c3e 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -44,6 +44,7 @@
  * the optimal version — two calls, each with their own speculation
  * trap should their return address end up getting used, in a loop.
  */
+#ifdef CONFIG_X86_64
 #define __FILL_RETURN_BUFFER(reg, nr, sp)	\
 	mov	$(nr/2), reg;			\
 771:						\
@@ -64,6 +65,19 @@
 	add	$(BITS_PER_LONG/8) * nr, sp;	\
 	/* barrier for jnz misprediction */	\
 	lfence;
+#else
+/*
+ * i386 doesn't unconditionally have LFENCE, as such it can't
+ * do a loop.
+ */
+#define __FILL_RETURN_BUFFER(reg, nr, sp)	\
+	.rept nr;				\
+	call	772f;				\
+	int3;					\
+772:;						\
+	.endr;					\
+	add	$(BITS_PER_LONG/8) * nr, sp;
+#endif
 
 #define __ISSUE_UNBALANCED_RET_GUARD(sp)	\
 	call	881f;				\