NetBSD does not have a <sys/module.h>, but it does have a <sys/lkm.h>
   that FreeBSD lacks.  Is anyone familiar enough with these two interfaces
   to explain what (generally) needs to be converted?

netbsd's LKM's are a subset of what freebsd provides, though there is
some level of compatibility due to having the same heritage.  hmm,
i thought there was a manual or tutorial but i can't find one.  there
are a lot of examples in netbsd src/sys/lkm.
   
   * #include <vm/vm.h>                                                                           
     #include <vm/vm_param.h>                                                                     
     #include <vm/vm_extern.h>                                                                    
     #include <vm/pmap.h>                                                                         
     #include <vm/vm_map.h>                                                                       
     #include <vm/vm_kern.h>                                                                      
     #include <vm/vm_page.h>
   
   This interface is used to control memory mapping, AFAICT.  Is there an
   equivalent interface in NetBSD?

see <uvm/uvm_extern.h> and uvm(9) manual, which should have everything
you need.


.mrg.