L4Linux LKM

karim.allah.ahmed at gmail.com karim.allah.ahmed at gmail.com
Wed Feb 3 14:57:22 CET 2016


Hello Nourhan,

You have to post kernel dmesg + the character device source code.

Regards.

On Wed, Feb 3, 2016 at 2:24 PM, Nourhan Mohamed
<nourhan.abdeltawab at gmail.com> wrote:
> Hi Karim,
>
> Worked really fine Thank you!
>
> I can use "open" to open the device. However I get a page fault whenever I
> attempt to write to the device. The device works properly on my ubuntu
> machine so I can't guess what can be the problem. Would really help if you
> have any suggestions.
>
> Thank you again
> BR,
> Nourhan
>
> On Wed, Feb 3, 2016 at 12:00 PM, karim.allah.ahmed at gmail.com
> <karim.allah.ahmed at gmail.com> wrote:
>>
>> Hello Nourhan,
>>
>> On Wed, Feb 3, 2016 at 11:47 AM, Nourhan Mohamed
>> <nourhan.abdeltawab at gmail.com> wrote:
>> > Dear all,
>> >
>> > I wanted to create a simple character device on L4Linux. I managed to
>> > cross-compile the module and run it on L4Linux on Versatile Express
>> > Realview
>> > Cortex-A15 ARM machine using the following command:
>> >
>> > make -C ~/l4re/obj/l4linux/arm-mp/ M=$PWD
>> > CROSS_COMPILE=/usr/bin/arm-linux-gnueabi- L4ARCH=arm CONFIG_TCG_TPM=m
>> > modules V=1
>> >
>> > When I try to insert the module using the insmod command I get the
>> > following
>> > printed out from the module:
>> > chardev: registered correctly with major number 254
>> > chardev: device class registered correctly
>> > chardev: device class created correctly
>> >
>> > With no failures in initializing the device printed at all. Also lsmod
>> > displays the device in the module list with status live.
>> >
>> > However, the device doesn't appear in the /dev/ directory and hence I
>> > can
>> > not access it using the file operations. Any ideas where is the device
>> > located or how can it be accessed on L4Linux?
>>
>> In linux systems, device nodes are not necessarily automatically
>> generated under /dev/.
>>
>> Use 'mknod' command-line to create a device node in user space that's
>> connected to this character device.
>>
>> Regards.
>>
>> >
>> >
>> > _______________________________________________
>> > l4-hackers mailing list
>> > l4-hackers at os.inf.tu-dresden.de
>> > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers
>> >
>>
>>
>>
>> --
>> Karim Allah Ahmed.
>
>



-- 
Karim Allah Ahmed.



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