L4Linux LKM

Nourhan Mohamed nourhan.abdeltawab at gmail.com
Wed Feb 3 14:24:33 CET 2016


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.
>
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