Hi... I could share something ... hopefully... On Mon, Oct 27, 2008 at 4:13 PM, nidhi mittal <nidhimittal19@xxxxxxxxx> wrote: > hi when i compiled a kernel module > i get two files a.o and a.ko file the .o file is individual object file, while the .ko is the result of linking every .o files to form the final kernel modules. > now my ques is .. > what is difference between two files.. > why two object files are created and actually makefile can be told to directly create the final .ko, but that way if you change single .c file (the source code) you have to repeat all the compilation process. That would slow down your compilation into some degree. But compiling each .c files into separate .o files, if you chance single .c file, only one .o file needs to be recompiled while the rest stay still. > then i read smwhere that when we do insmod all symbols used in code are > linked with kernel symbol table.... correct....the external symbols. > then 2nd place i read is insmod does loading of module linking is already > done while making .ko file ... resolving and linking symbols happens during the loading of kernel module . It's the same when you run a binary that relies on dynamic shared libraries. > and last is i have learnt writing makefile for kernel module but dont > understand why do they reuire first > > make -C <kernel makefile path> M = <my module makefile path> modules > i read abt it in LDD too but cd nt understand > as to why do we make it first reach to kernel make file then to our makefile > and what modules target specify... AFAIK, it is done that way so you don't have to specify things like library path, CFLAGS and so on. Everything is already defined in main kernel source's Makefile. So, you get advantage that your Makefile looks cleaner and more portable. regards, Mulyadi. -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
