diff --git a/sim/bfin/ChangeLog b/sim/bfin/ChangeLog
index 196725175c3..539313888b2 100644
--- a/sim/bfin/ChangeLog
+++ b/sim/bfin/ChangeLog
@@ -1,3 +1,7 @@
+2015-06-12  Mike Frysinger  <vapier@gentoo.org>
+
+	* interp.c: Expand comment on CB_SYS_xxx defines.
+
 2015-06-12  Mike Frysinger  <vapier@gentoo.org>
 
 	* configure: Regenerate.
diff --git a/sim/bfin/interp.c b/sim/bfin/interp.c
index bed7564cc14..69b5e96d627 100644
--- a/sim/bfin/interp.c
+++ b/sim/bfin/interp.c
@@ -36,7 +36,9 @@
 
 #include "targ-vals.h"
 
-/* The numbers here do not matter.  They just need to be unique.  */
+/* The numbers here do not matter.  They just need to be unique.  They also
+   need not be static across releases -- they're used internally only.  The
+   mapping from the Linux ABI to the CB values is in linux-targ-map.h.  */
 #define CB_SYS_ioctl        201
 #define CB_SYS_mmap2        202
 #define CB_SYS_munmap       203