slotspace_rand
va = slotspace_rand(SLAREA_MAIN, NKL4_MAX_ENTRIES * NBPD_L4,
va = slotspace_rand(SLAREA_PTE, NBPD_L4, NBPD_L4, randhole, randva);
vaddr_t slotspace_rand(int, size_t, size_t, size_t, vaddr_t);
startva = slotspace_rand(SLAREA_DMAP, lastpa, NBPD_L2,