get_pcb_td
thread0.td_pcb = get_pcb_td(&thread0);
td2->td_pcb = pcb2 = get_pcb_td(td2);
td->td_pcb = pcb = get_pcb_td(td);
thread0.td_pcb = get_pcb_td(&thread0);
pcb2 = get_pcb_td(td2);
td->td_pcb = pcb = get_pcb_td(td);
(total) = (vm_offset_t)get_pcb_td(td) - td->td_kstack; \
(used) = (vm_offset_t)get_pcb_td(td) - (vm_offset_t)&td; \
va + len <= (vm_offset_t)get_pcb_td(td));
struct pcb *get_pcb_td(struct thread *td);