Compile external module against linux source and use functionality in linux source

[Paul Bolle]

On Thu, 2014-09-25 at 12:30 +0530, Arjun Pandey wrote:
> On Thu, Sep 25, 2014 at 12:28 PM, Paul Bolle <pebolle at tiscali.nl> wrote:
> > On Thu, 2014-09-25 at 12:24 +0530, Arjun Pandey wrote:
> >> I tried moving the module to kernel tree as well. Ideally this will be
> >> out of tree module. That still didn't work.
> >> I have included a header file with the extern function declaration in
> >> the source file that i modified.
> >> That didn't help either.

Building a module built-in requires a bit more: changes to a kernel tree
Kconfig file and a Makefile. There must be a lot of documentation on
this. But I would do something like
    git grep -w tristate $(git ls-files "net/*Kconfig*")

and pick a few Kconfig symbols (ie, the things with lines reading
"config EXAMPLE"). The grep the tree again for their macros:
    git grep -w "CONFIG_EXAMPLE" net/

and figure out how things all fit together.

(My guess, of course, is that your linker error disappears when you
manege to build the module built-in. Once we know that, we can look
whether it's actually possible to achieve what you want to do with an
external module.)

Hope this helps.


Paul Bolle