Hi Kent,

no, I didn't changed the implementation of the poke module, just modified
the string to be printed.

Hugo,

El jue., 1 jul. 2021 9:26, Kent Mcleod <[email protected]> escribió:

> On Thu, Jun 24, 2021 at 8:03 PM Hugo V.C. <[email protected]> wrote:
> >
> > Hi,
> >
> > just a simple question: why this tutorial:
> >
> > https://docs.sel4.systems/Tutorials/camkes-vm-linux.html
> >
> > shows this output:
> >
> > Welcome to Buildroot
> > buildroot login: root
> > Password:
> > # grep poke /proc/devices        # figure out the major number of our
> driver
> > 244 poke
> > # mknod /dev/poke c 244 0        # create the special file
> > # echo > /dev/poke               # write to the file
> > [ 57.389643] hi
> > -sh: write error: Bad address    # the shell complains, but our module
> > is being invoked!
> >
> >
> > I'm not getting the shell complain error, just this:
> >
> > # grep poke /proc/devices
> > 247 poke
> > # mknod /dev/poke c 247 0
> > # echo > /dev/poke
> > [  138.946905] TOC TOC NEO...
> > #
> >
> > FYI: my kernel is a custom compiled one but same version as the
> > pre-compiled you provide:
> >
> > # uname -a
> > Linux buildroot 4.9.189 #4 SMP Thu Jun 24 00:16:49 CEST 2021 aarch64
> > GNU/Linux
> >
> > Any hint?
>
> Have you changed the implementation of poke_write?  By the end of the
> tutorial there isn't a write error in the example shell output.  I
> think if the kernel module returns a different length result than what
> was requested the shell interprets this as a write error.  If you
> return the correct length that was requested then there would be no
> error.  (This is a guess though)
>
> Kent.
>
>
>
> > Cheers,
> > _______________________________________________
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>
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