cpu_poweroff
int cpu_poweroff(cpu_t *); /* take offline cpu to powered-off */
if (cpu_poweroff(cp) != 0) {
if (e = cpu_poweroff(cpu)) {
if (cpu_poweroff(cp) != 0) {
if ((error = cpu_poweroff(cpa)) != 0) {
if ((error = cpu_poweroff(cpb)) != 0) {
if ((rv = cpu_poweroff(cp)) != 0) {