ustack             32 kernel/exec.c    uint64 argc, sz = 0, sp, ustack[MAXARG], stackbase;
ustack            108 kernel/exec.c      ustack[argc] = sp;
ustack            110 kernel/exec.c    ustack[argc] = 0;
ustack            117 kernel/exec.c    if (copyout(pagetable, sz, sp, (char *)ustack, (argc + 1) * sizeof(uint64)) <