Index: kern/kern_mib.c
===================================================================
--- kern/kern_mib.c	(revision 258815)
+++ kern/kern_mib.c	(working copy)
@@ -261,6 +261,13 @@
 SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD,
     NULL, 0, sysctl_hw_machine_arch, "A", "System architecture");
 
+SYSCTL_STRING(_kern, OID_AUTO, supported_abis, CTLFLAG_RD|CTLFLAG_MPSAFE,
+#ifdef COMPAT_FREEBSD32
+    MACHINE_ARCH " " MACHINE_ARCH32, 0, "List of supported ABIs");
+#else
+    MACHINE_ARCH, 0, "List of supported ABIs");
+#endif
+
 static int
 sysctl_hostname(SYSCTL_HANDLER_ARGS)
 {