ZONE(9): Enable per-processor cache for SMP

This prevents a potential deadlock via the Giant lock and is a
performance benefit.

freebsd/sys/sys/systm.h

@@ -209,13 +209,13 @@ void	critical_exit(void);
 static __inline void
 critical_enter(void)
 {
-	_Thread_Disable_dispatch();
+	_Thread_Dispatch_disable();
 }
 
 static __inline void
 critical_exit(void)
 {
-	_Thread_Enable_dispatch();
+	_Thread_Dispatch_enable(_Per_CPU_Get());
 }
 #endif /* __rtems__ */
 void	init_param1(void);

freebsd/sys/vm/uma_core.c

@@ -89,6 +89,18 @@ __FBSDID("$FreeBSD$");
 #include <vm/uma_dbg.h>
 
 #include <ddb/ddb.h>
+#ifdef __rtems__
+  #ifdef RTEMS_SMP
+    /*
+     * It is essential that we have a per-processor cache, otherwise the
+     * critical_enter()/critical_exit() protection would be insufficient.
+     */
+    #undef curcpu
+    #define curcpu rtems_get_current_processor()
+    #undef mp_maxid
+    #define mp_maxid rtems_get_processor_count()
+  #endif
+#endif /* __rtems__ */
 
 /*
  * This is the zone and keg from which all zones are spawned.  The idea is that