PHYSTOP            30 kernel/kalloc.c   freerange(end, (void *)PHYSTOP);
PHYSTOP            51 kernel/kalloc.c   if (((uint64)pa % PGSIZE) != 0 || (char *)pa < end || (uint64)pa >= PHYSTOP)
PHYSTOP            42 kernel/vm.c      kvmmap(kpgtbl, (uint64)etext, (uint64)etext, PHYSTOP - (uint64)etext,