diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ea262b0..c001766 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -45,7 +45,9 @@
 #define BPF_EXIT	0x90	/* function return */
 
 /* atomic op type fields (stored in immediate) */
-#define BPF_FETCH	0x01	/* fetch previous value into src reg */
+#define BPF_FETCH	0x01	/* not an opcode on its own, used to build others */
+#define BPF_XCHG	(0xe0 | BPF_FETCH)	/* atomic exchange */
+#define BPF_CMPXCHG	(0xf0 | BPF_FETCH)	/* atomic compare-and-write */
 
 /* Register numbers */
 enum {