PMAP_L2_SIZE
((vaddr_t) kernel_pm_entries + l1 * PMAP_L2_SIZE);
kmem_free(l2tbl, PMAP_L2_SIZE);
#define PMAP_L2_NENTRY (PMAP_L2_SIZE / sizeof(struct pv_entry *))
l2tbl = pmap->pm_l1[l1] = kmem_zalloc(PMAP_L2_SIZE, KM_SLEEP);