Linux Device Driver Programming (unable to find headers)

arn_ml · 11-23-2009, 12:01 AM

Hi Everybody,
I am very new to device driver programming and for that i am referring to
O'Reilly's LDD Programming.
And I am doing this on Fedora Core 11 which i had got with a Linux magazine(Linux For You).

1)After writing my hello_world module i was unable to compile the module using gcc to get a ".ko" object file.
From the errors it showed it could be seen that it was unable to find
<linux/module.h>,<linux/init.h> and respective macros.

2)After searching on it a bit ,i installed the kernel-devel* and kernel-headers* packages which came along with the dvd.
Even after that i was unable to compile.

3)So, i decided to compile the kernel 2.6.27.39 manuallyhttp://www.kernel.org/

To compile the kernel i followed the instructions given in the sitehttp://www.cyberciti.biz/tips/compil...kernel-26.html

I replaced the /usr/src mentioned in the site to /usr/src/kernels, as all my kernels were listed in the directory.
I think every step were done without errors , but when i booted with that kernel the booting process hanged at the last stage and many things regarding SS,DS,ES were shown on the screen.

So, I am stuck with it.

Thanks in advance for any kind of help.

Anisha Kaul · 11-23-2009, 12:54 AM

Quote:

After writing my hello_world module i was unable to compile the module using gcc to get a ".ko" object file.

U can't compile a kernel module using gcc. U need to write a makefile for it. Below is an example of writing a makefile for a kernel module.

Code:

obj-m += moduleName.o

all:
        make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
        make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

Quote:

After searching on it a bit ,i installed the kernel-devel* and kernel-headers* packages which came along with the dvd.
Even after that i was unable to compile.

First u try to compile the kernel module through the above shown makefile, then tell us the errors generated.

And there is no need to compile the linux kernel yet ! Work on a normal pre-compiled kernel !

arn_ml · 11-23-2009, 01:26 AM

thanks for the reply.
I forgot to mention that i did make the Makefile.
<hello1>=
obj-m := hello.o

But since i didnt knew how to make it i tried it next with gcc(simple `make` command doesnt work)

The book which i refer says something about kernel-source tree and i have no idea of it.
I will paste a few lines from the book:

"Regardless of the origin of your kernel, building modules for 2.6.x requires that you have a configured and built kernel tree on your system. This requirement is a change from previous versions of the kernel, where a current set of header files was sufficient. 2.6 modules are linked against object files found in the kernel source tree; the result is a more robust module loader, but also the requirement that those object files be available. So your first order of business is to come up with a kernel source tree (either from the kernel.org network or your distributor's kernel source package), build a new kernel, and install it on your system. "

Can you explain this thing to me?
Again thanks for replying.

Anisha Kaul · 11-23-2009, 01:34 AM

First please tell me have u written the makefile exactly the way i told u. If not write it in that way and then tell me the results. Meanwhile I'll study the para u have copied from the book !

Kindly show all the code u are trying to compile !

arn_ml · 11-23-2009, 02:24 AM

I dont think i understood that correctly.I would be glad if you could link me up to a good tutorial for understanding makefiles.
Anyways the out put i got is:

bash: PWD: command not found
make: Entering directory `/usr/src/kernels/2.6.29.4-167.fc11.i586'
CHK include/linux/version.h
CHK include/linux/utsrelease.h
SYMLINK include/asm -> include/asm-x86
make[1]: *** No rule to make target `missing-syscalls'. Stop.
make: *** [prepare0] Error 2
make: Leaving directory `/usr/src/kernels/2.6.29.4-167.fc11.i586'

Anisha Kaul · 11-23-2009, 02:29 AM

Have u included tabs instead of spaces in u r makefile. Check it twice because it is required.

Secondly u have not shown u r device driver code.
Kindly show all codes including the makefile u have written!

filename: Makefile

Code:

obj-m += moduleName.o

all:
<TAB>make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
<TAB>make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

Quote:

(simple `make` command doesnt work)

make command executes the makefile, since u have not written it, it is not supposed to work !

arn_ml · 11-23-2009, 03:47 AM

Ok.i had earlier provided spaces instead of tab.Problem Solved.
Thank you very much madam.
It would be very nice if you could provide me with some tutorial so that i can understand what exactly does the above makefile do and how does make command resolve the dependencies.

Again,Thank You very much.

Anisha Kaul · 01-04-2010, 11:53 PM

Quote:

Originally Posted by arn_ml

It would be very nice if you could provide me with some tutorial so that i can understand what exactly does the above makefile do and how does make command resolve the dependencies.

Try the following links, see if they help u !

1. http://makepp.sourceforge.net/1.19/makepp_tutorial.html

2. http://www.cs.colby.edu/maxwell/cour...als/maketutor/

arn_ml · 01-10-2010, 07:12 AM

thank you.
i will surely go through these links.