diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1e753cd3f70..79f5357d548 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2017-12-27  Stafford Horne  <shorne@gmail.com>
+
+	* reggroups.c (reggroups_init): Change to depend only on
+	obstack rather than gdbarch.
+	(reggroup_add): Remove logic for forcing premature init.
+	(_initialize_reggroup): Set `reggroups_data` with
+	gdbarch_data_register_pre_init() rather than
+	gdbarch_data_register_post_init().
+
 2017-12-27  Stafford Horne  <shorne@gmail.com>
 
 	* infcmd.c (_initialize_infcmd): Add help for info reg $reggroup
diff --git a/gdb/reggroups.c b/gdb/reggroups.c
index 2ecd0b494f7..5d5e33f2a35 100644
--- a/gdb/reggroups.c
+++ b/gdb/reggroups.c
@@ -26,6 +26,7 @@
 #include "regcache.h"
 #include "command.h"
 #include "gdbcmd.h"		/* For maintenanceprintlist.  */
+#include "gdb_obstack.h"
 
 /* Individual register groups.  */
 
@@ -76,10 +77,9 @@ struct reggroups
 static struct gdbarch_data *reggroups_data;
 
 static void *
-reggroups_init (struct gdbarch *gdbarch)
+reggroups_init (struct obstack *obstack)
 {
-  struct reggroups *groups = GDBARCH_OBSTACK_ZALLOC (gdbarch,
-						     struct reggroups);
+  struct reggroups *groups = OBSTACK_ZALLOC (obstack, struct reggroups);
 
   groups->last = &groups->first;
   return groups;
@@ -105,13 +105,6 @@ reggroup_add (struct gdbarch *gdbarch, struct reggroup *group)
   struct reggroups *groups
     = (struct reggroups *) gdbarch_data (gdbarch, reggroups_data);
 
-  if (groups == NULL)
-    {
-      /* ULGH, called during architecture initialization.  Patch
-         things up.  */
-      groups = (struct reggroups *) reggroups_init (gdbarch);
-      deprecated_set_gdbarch_data (gdbarch, reggroups_data, groups);
-    }
   add_group (groups, group,
 	     GDBARCH_OBSTACK_ZALLOC (gdbarch, struct reggroup_el));
 }
@@ -298,7 +291,7 @@ struct reggroup *const restore_reggroup = &restore_group;
 void
 _initialize_reggroup (void)
 {
-  reggroups_data = gdbarch_data_register_post_init (reggroups_init);
+  reggroups_data = gdbarch_data_register_pre_init (reggroups_init);
 
   /* The pre-defined list of groups.  */
   add_group (&default_groups, general_reggroup, XNEW (struct reggroup_el));