diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -1112,15 +1112,18 @@
 #endif
 
 /*
- * General init routine used by the MTX_SYSINIT() macro.
+ * General init and uninit routines used by the MTX_SYSINIT() macro.
  */
 void
-mtx_sysinit(void *arg)
+mtx_sysinit(const struct mtx_args *margs)
 {
-	struct mtx_args *margs = arg;
+	mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
+}
 
-	mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL,
-	    margs->ma_opts);
+void
+mtx_sysuninit(const struct mtx_args *margs)
+{
+	mtx_destroy(margs->ma_mtx);
 }
 
 /*
diff --git a/sys/kern/kern_rmlock.c b/sys/kern/kern_rmlock.c
--- a/sys/kern/kern_rmlock.c
+++ b/sys/kern/kern_rmlock.c
@@ -339,14 +339,17 @@
 }
 
 void
-rm_sysinit(void *arg)
+rm_sysinit(const struct rm_args *args)
 {
-	struct rm_args *args;
-
-	args = arg;
 	rm_init_flags(args->ra_rm, args->ra_desc, args->ra_flags);
 }
 
+void
+rm_sysuninit(const struct rm_args *args)
+{
+	rm_destroy(args->ra_rm);
+}
+
 static __noinline int
 _rm_rlock_hard(struct rmlock *rm, struct rm_priotracker *tracker, int trylock)
 {
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c
--- a/sys/kern/kern_rwlock.c
+++ b/sys/kern/kern_rwlock.c
@@ -254,13 +254,15 @@
 }
 
 void
-rw_sysinit(void *arg)
+rw_sysinit(const struct rw_args *args)
 {
-	struct rw_args *args;
+	rw_init_flags(args->ra_rw, args->ra_desc, args->ra_flags);
+}
 
-	args = arg;
-	rw_init_flags((struct rwlock *)args->ra_rw, args->ra_desc,
-	    args->ra_flags);
+void
+rw_sysuninit(const struct rw_args *args)
+{
+	rw_destroy(args->ra_rw);
 }
 
 int
diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c
--- a/sys/kern/kern_sx.c
+++ b/sys/kern/kern_sx.c
@@ -225,13 +225,17 @@
 #endif
 
 void
-sx_sysinit(void *arg)
+sx_sysinit(const struct sx_args *sargs)
 {
-	struct sx_args *sargs = arg;
-
 	sx_init_flags(sargs->sa_sx, sargs->sa_desc, sargs->sa_flags);
 }
 
+void
+sx_sysuninit(const struct sx_args *sargs)
+{
+	sx_destroy(sargs->sa_sx);
+}
+
 void
 sx_init_flags(struct sx *sx, const char *description, int opts)
 {
diff --git a/sys/sys/mutex.h b/sys/sys/mutex.h
--- a/sys/sys/mutex.h
+++ b/sys/sys/mutex.h
@@ -45,6 +45,8 @@
 #include <machine/atomic.h>
 #include <machine/cpufunc.h>
 
+struct mtx_args;
+
 /*
  * Mutex types and options passed to mtx_init().  MTX_QUIET and MTX_DUPOK
  * can also be passed in.
@@ -92,7 +94,8 @@
 void	_mtx_init(volatile uintptr_t *c, const char *name, const char *type,
 	    int opts);
 void	_mtx_destroy(volatile uintptr_t *c);
-void	mtx_sysinit(void *arg);
+void	mtx_sysinit(const struct mtx_args *);
+void	mtx_sysuninit(const struct mtx_args *);
 int	_mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF);
 int	_mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file,
 	    int line);
@@ -519,13 +522,13 @@
 #endif
 
 struct mtx_args {
-	void		*ma_mtx;
+	struct mtx 	*ma_mtx;
 	const char 	*ma_desc;
 	int		 ma_opts;
 };
 
 #define	MTX_SYSINIT(name, mtx, desc, opts)				\
-	static struct mtx_args name##_args = {				\
+	static const struct mtx_args name##_args = {			\
 		(mtx),							\
 		(desc),							\
 		(opts)							\
@@ -533,7 +536,7 @@
 	SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    mtx_sysinit, &name##_args);					\
 	SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
-	    _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
+	    mtx_sysuninit, &name##_args);
 
 /*
  * The INVARIANTS-enabled mtx_assert() functionality.
diff --git a/sys/sys/rmlock.h b/sys/sys/rmlock.h
--- a/sys/sys/rmlock.h
+++ b/sys/sys/rmlock.h
@@ -50,11 +50,14 @@
 #define	RM_NEW		0x00000008
 #define	RM_DUPOK	0x00000010
 
+struct rm_args;
+
 void	rm_init(struct rmlock *rm, const char *name);
 void	rm_init_flags(struct rmlock *rm, const char *name, int opts);
 void	rm_destroy(struct rmlock *rm);
 int	rm_wowned(const struct rmlock *rm);
-void	rm_sysinit(void *arg);
+void	rm_sysinit(const struct rm_args *);
+void	rm_sysuninit(const struct rm_args *);
 
 void	_rm_wlock_debug(struct rmlock *rm, const char *file, int line);
 void	_rm_wunlock_debug(struct rmlock *rm, const char *file, int line);
@@ -107,7 +110,7 @@
 };
 
 #define	RM_SYSINIT_FLAGS(name, rm, desc, flags)				\
-	static struct rm_args name##_args = {				\
+	static const struct rm_args name##_args = {			\
 		(rm),							\
 		(desc),							\
 		(flags),						\
@@ -115,7 +118,7 @@
 	SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    rm_sysinit, &name##_args);					\
 	SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
-	    rm_destroy, (rm))
+	    rm_sysuninit, &name##_args)
 
 #define	RM_SYSINIT(name, rm, desc)	RM_SYSINIT_FLAGS(name, rm, desc, 0)
 
diff --git a/sys/sys/rwlock.h b/sys/sys/rwlock.h
--- a/sys/sys/rwlock.h
+++ b/sys/sys/rwlock.h
@@ -76,6 +76,8 @@
 
 #ifdef _KERNEL
 
+struct rw_args;
+
 #define	rw_recurse	lock_object.lo_data
 
 #define	RW_READ_VALUE(x)	((x)->rw_lock)
@@ -130,7 +132,8 @@
  */
 void	_rw_init_flags(volatile uintptr_t *c, const char *name, int opts);
 void	_rw_destroy(volatile uintptr_t *c);
-void	rw_sysinit(void *arg);
+void	rw_sysinit(const struct rw_args *);
+void	rw_sysuninit(const struct rw_args *);
 int	_rw_wowned(const volatile uintptr_t *c);
 void	_rw_wlock_cookie(volatile uintptr_t *c, const char *file, int line);
 int	__rw_try_wlock_int(struct rwlock *rw LOCK_FILE_LINE_ARG_DEF);
@@ -247,13 +250,13 @@
 #define	rw_initialized(rw)	lock_initialized(&(rw)->lock_object)
 
 struct rw_args {
-	void		*ra_rw;
+	struct rwlock 	*ra_rw;
 	const char 	*ra_desc;
 	int		ra_flags;
 };
 
 #define	RW_SYSINIT_FLAGS(name, rw, desc, flags)				\
-	static struct rw_args name##_args = {				\
+	static const struct rw_args name##_args = {			\
 		(rw),							\
 		(desc),							\
 		(flags),						\
@@ -261,7 +264,7 @@
 	SYSINIT(name##_rw_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    rw_sysinit, &name##_args);					\
 	SYSUNINIT(name##_rw_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
-	    _rw_destroy, __DEVOLATILE(void *, &(rw)->rw_lock))
+	    rw_sysuninit, &name##_args)
 
 #define	RW_SYSINIT(name, rw, desc)	RW_SYSINIT_FLAGS(name, rw, desc, 0)
 
diff --git a/sys/sys/sx.h b/sys/sys/sx.h
--- a/sys/sys/sx.h
+++ b/sys/sys/sx.h
@@ -90,6 +90,8 @@
 
 #ifdef _KERNEL
 
+struct sx_args;
+
 #define	sx_recurse	lock_object.lo_data
 
 #define	SX_READ_VALUE(sx)	((sx)->sx_lock)
@@ -101,7 +103,8 @@
  * Function prototipes.  Routines that start with an underscore are not part
  * of the public interface and are wrappered with a macro.
  */
-void	sx_sysinit(void *arg);
+void	sx_sysinit(const struct sx_args *);
+void	sx_sysuninit(const struct sx_args *);
 #define	sx_init(sx, desc)	sx_init_flags((sx), (desc), 0)
 void	sx_init_flags(struct sx *sx, const char *description, int opts);
 void	sx_destroy(struct sx *sx);
@@ -135,7 +138,7 @@
 };
 
 #define	SX_SYSINIT_FLAGS(name, sxa, desc, flags)			\
-	static struct sx_args name##_args = {				\
+	static const struct sx_args name##_args = {			\
 		(sxa),							\
 		(desc),							\
 		(flags)							\
@@ -143,7 +146,7 @@
 	SYSINIT(name##_sx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    sx_sysinit, &name##_args);					\
 	SYSUNINIT(name##_sx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
-	    sx_destroy, (sxa))
+	    sx_sysuninit, &name##_args)
 
 #define	SX_SYSINIT(name, sxa, desc)	SX_SYSINIT_FLAGS(name, sxa, desc, 0)