if (!defined &_VM_MAP_) {
    eval 'sub _VM_MAP_ {1;}';
    eval 'sub min_offset { &header. &start;}';
    eval 'sub max_offset { &header. &end;}';
    eval 'sub vm_map_lock {
        local($map) = @_;
        eval "{  &lock_write(&($map)-> &lock); ($map)-> &timestamp++; }";
    }';
    eval 'sub vm_map_unlock {
        local($map) = @_;
        eval " &lock_write_done(&($map)-> &lock)";
    }';
    eval 'sub vm_map_lock_read {
        local($map) = @_;
        eval " &lock_read(&($map)-> &lock)";
    }';
    eval 'sub vm_map_unlock_read {
        local($map) = @_;
        eval " &lock_read_done(&($map)-> &lock)";
    }';
    eval 'sub vm_map_min {
        local($map) = @_;
        eval "(($map)-> &min_offset)";
    }';
    eval 'sub vm_map_max {
        local($map) = @_;
        eval "(($map)-> &max_offset)";
    }';
    eval 'sub vm_map_pmap {
        local($map) = @_;
        eval "(($map)-> &pmap)";
    }';
    eval 'sub MAX_KMAP {10;}';
    eval 'sub MAX_KMAPENT {500;}';
    if (defined &KERNEL) {
    }
}
1;