Index: sys/riscv/riscv/pmap.c
===================================================================
--- sys/riscv/riscv/pmap.c
+++ sys/riscv/riscv/pmap.c
@@ -486,8 +486,13 @@
 	struct pmap *user_pmap;
 	pd_entry_t *l1;
 
-	/* Distribute new kernel L1 entry to all the user pmaps */
-	if (pmap != kernel_pmap)
+	/*
+	 * Distribute new kernel L1 entry to all the user pmaps.  This is only
+	 * necessary with three-level paging configured: with four-level paging
+	 * the kernel's half of the top-level page table page is static and can
+	 * simply be copied at pmap initialization time.
+	 */
+	if (pmap != kernel_pmap || pmap_mode != PMAP_MODE_SV39)
 		return;
 
 	mtx_lock(&allpmaps_lock);
@@ -1278,11 +1283,15 @@
 
 	CPU_ZERO(&pmap->pm_active);
 
-	mtx_lock(&allpmaps_lock);
-	LIST_INSERT_HEAD(&allpmaps, pmap, pm_list);
-	mtx_unlock(&allpmaps_lock);
+	if (pmap_mode == PMAP_MODE_SV39) {
+		mtx_lock(&allpmaps_lock);
+		LIST_INSERT_HEAD(&allpmaps, pmap, pm_list);
+		mtx_unlock(&allpmaps_lock);
 
-	memcpy(pmap->pm_top, kernel_pmap->pm_top, PAGE_SIZE);
+		memcpy(pmap->pm_top, kernel_pmap->pm_top, PAGE_SIZE);
+	} else {
+		memcpy(pmap->pm_top, kernel_pmap->pm_top, PAGE_SIZE);
+	}
 
 	vm_radix_init(&pmap->pm_root);
 
@@ -1472,9 +1481,11 @@
 	KASSERT(CPU_EMPTY(&pmap->pm_active),
 	    ("releasing active pmap %p", pmap));
 
-	mtx_lock(&allpmaps_lock);
-	LIST_REMOVE(pmap, pm_list);
-	mtx_unlock(&allpmaps_lock);
+	if (pmap_mode == PMAP_MODE_SV39) {
+		mtx_lock(&allpmaps_lock);
+		LIST_REMOVE(pmap, pm_list);
+		mtx_unlock(&allpmaps_lock);
+	}
 
 	m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)pmap->pm_top));
 	vm_page_unwire_noq(m);