L2_TRUNC_BLOCK
pmapboot_protect(L2_TRUNC_BLOCK(kernstart),
L2_TRUNC_BLOCK(data_start), VM_PROT_WRITE);
kernstart_l2 = L2_TRUNC_BLOCK(kernstart);
const vaddr_t fva = L2_TRUNC_BLOCK(kernstart);
#define L2_ROUND_BLOCK(x) L2_TRUNC_BLOCK((x) + L2_SIZE - 1)