diff --git a/sys/kern/kern_subr.c b/sys/kern/kern_subr.c
index 2de9d776b84..931a893f002 100644
--- a/sys/kern/kern_subr.c
+++ b/sys/kern/kern_subr.c
@@ -448,7 +448,8 @@ uio_yield(void)
 }
 
 int
-copyinfrom(const void *src, void *dst, size_t len, int seg)
+copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
+    int seg)
 {
 	int error = 0;
 
@@ -466,7 +467,8 @@ copyinfrom(const void *src, void *dst, size_t len, int seg)
 }
 
 int
-copyinstrfrom(const void *src, void *dst, size_t len, size_t *copied, int seg)
+copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
+    size_t * __restrict copied, int seg)
 {
 	int error = 0;
 
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 5ecae0fac62..6c1f4b33b69 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -185,12 +185,16 @@ void	bzero(void *buf, size_t len) __nonnull(1);
 
 void	*memcpy(void *to, const void *from, size_t len) __nonnull(1) __nonnull(2);
 
-int	copystr(const void *kfaddr, void *kdaddr, size_t len,
-	    size_t *lencopied) __nonnull(1) __nonnull(2);
-int	copyinstr(const void *udaddr, void *kaddr, size_t len,
-	    size_t *lencopied) __nonnull(1) __nonnull(2);
-int	copyin(const void *udaddr, void *kaddr, size_t len) __nonnull(1) __nonnull(2);
-int	copyout(const void *kaddr, void *udaddr, size_t len) __nonnull(1) __nonnull(2);
+int	copystr(const void * __restrict kfaddr, void * __restrict kdaddr,
+	    size_t len, size_t * __restrict lencopied)
+	    __nonnull(1) __nonnull(2);
+int	copyinstr(const void * __restrict udaddr, void * __restrict kaddr,
+	    size_t len, size_t * __restrict lencopied)
+	    __nonnull(1) __nonnull(2);
+int	copyin(const void * __restrict udaddr, void * __restrict kaddr,
+	    size_t len) __nonnull(1) __nonnull(2);
+int	copyout(const void * __restrict kaddr, void * __restrict udaddr,
+	    size_t len) __nonnull(1) __nonnull(2);
 
 int	fubyte(const void *base);
 long	fuword(const void *base);
diff --git a/sys/sys/uio.h b/sys/sys/uio.h
index 3bcc42e8bcf..82c78ae3b42 100644
--- a/sys/sys/uio.h
+++ b/sys/sys/uio.h
@@ -89,9 +89,10 @@ void	uio_yield(void);
 int	uiomove(void *, int, struct uio *);
 int	uiomove_frombuf(void *buf, int buflen, struct uio *uio);
 int	uiomoveco(void *, int, struct uio *, struct vm_object *, int);
-int	copyinfrom(const void *src, void *dst, size_t len, int seg);
-int	copyinstrfrom(const void *src, void *dst, size_t len,
-	    size_t *copied, int seg);
+int	copyinfrom(const void * __restrict src, void * __restrict dst,
+	    size_t len, int seg);
+int	copyinstrfrom(const void * __restrict src, void * __restrict dst,
+	    size_t len, size_t * __restrict copied, int seg);
 
 #else /* !_KERNEL */