diff --git a/sys/uvm/uvm_extern.h b/sys/uvm/uvm_extern.h
index 40bc23157934..8568f8e3dc53 100644
--- a/sys/uvm/uvm_extern.h
+++ b/sys/uvm/uvm_extern.h
@@ -699,10 +699,14 @@ int			uvm_io(struct vm_map *, struct uio *, int);
 /* uvm_km.c */
 vaddr_t			uvm_km_alloc(struct vm_map *, vsize_t, vsize_t,
 			    uvm_flag_t);
+int			uvm_km_allocjit(struct vm_map *, vaddr_t *, vaddr_t *,
+			    vsize_t, vsize_t, uvm_flag_t);
 int			uvm_km_protect(struct vm_map *, vaddr_t, vsize_t,
 			    vm_prot_t);
 void			uvm_km_free(struct vm_map *, vaddr_t, vsize_t,
 			    uvm_flag_t);
+void			uvm_km_freejit(struct vm_map *, vaddr_t, vaddr_t,
+			    vsize_t, uvm_flag_t);
 
 struct vm_map		*uvm_km_suballoc(struct vm_map *, vaddr_t *,
 			    vaddr_t *, vsize_t, int, bool,
diff --git a/sys/uvm/uvm_km.c b/sys/uvm/uvm_km.c
index e5a06fec87ea..5d6dd2c8abad 100644
--- a/sys/uvm/uvm_km.c
+++ b/sys/uvm/uvm_km.c
@@ -721,6 +721,64 @@ uvm_km_alloc(struct vm_map *map, vsize_t size, vsize_t align, uvm_flag_t flags)
 	return(kva);
 }
 
+/*
+ * uvm_km_allocjit: allocate an area of kernel JIT memory.
+ *
+ * => NOTE: we can return 0 even if we can wait if there is not enough
+ *	free VM space in the map... caller should be prepared to handle
+ *	this case.
+ * => We return writable KVA of memory allocated in data and executable
+ *    in code. On a successful allocation, return 0.
+ */
+
+int
+uvm_km_allocjit(struct vm_map *map, vaddr_t *rdata, vaddr_t *rcode,
+	vsize_t size, vsize_t align, uvm_flag_t flags)
+{
+	struct pmap *pmap;
+	vaddr_t data, code;
+	vaddr_t kva, end;
+	paddr_t pa;
+
+	KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED);
+	KASSERT(map == kernel_map);
+
+	data = uvm_km_alloc(map, size, align, flags);
+	if (data == 0)
+		return -1;
+
+	code = uvm_km_alloc(map, size, align, UVM_KMF_VAONLY);
+	if (code == 0) {
+		uvm_km_free(map, data, size, UVM_KMF_WIRED);
+		return -1;
+	}
+
+	pmap = map->pmap;
+	for (kva = code, end = code + size; kva < end; kva += PAGE_SIZE) {
+		if (!pmap_extract(pmap, kva, &pa)) {
+			return fail;
+		}
+		pmap_kenter_pa(kva, pa, VM_PROT_READ | VM_PROT_EXECUTE,
+			       PMAP_WIRED);
+	}
+	pmap_update(pmap);
+
+	if (rdata)
+		*rdata = data;
+	if (rcode)
+		*rcode = code;
+	return 0;
+
+fail:
+	if (kva > code) {
+		pmap_kremove(code, kva - code);
+		pmap_update(pmap);
+	}
+	uvm_km_free(map, data, size, UVM_KMF_VAONLY);
+	uvm_km_free(map, code, size, UVM_KMF_WIRED);
+	return -1;
+}
+
 /*
  * uvm_km_protect: change the protection of an allocated area
  */
@@ -766,6 +824,25 @@ uvm_km_free(struct vm_map *map, vaddr_t addr, vsize_t size, uvm_flag_t flags)
 	uvm_unmap1(map, addr, addr + size, UVM_FLAG_VAONLY);
 }
 
+/*
+ * uvm_km_freejit: free a JIT area of kernel memory
+ */
+
+void
+uvm_km_freejit(struct vm_map *map, vaddr_t data, vaddr_t code, vsize_t size,
+	uvm_flag_t flags)
+{
+
+	KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED);
+	KASSERT(map == kernel_map);
+
+	pmap_kremove(code, size);
+	pmap_update(map->pmap);
+
+	uvm_km_free(map, data, size, UVM_KMF_VAONLY);
+	uvm_km_free(map, code, size, UVM_KMF_WIRED);
+}
+
 /* Sanity; must specify both or none. */
 #if (defined(PMAP_MAP_POOLPAGE) || defined(PMAP_UNMAP_POOLPAGE)) && \
     (!defined(PMAP_MAP_POOLPAGE) || !defined(PMAP_UNMAP_POOLPAGE))