[PATCH] staging: comedi: ni_mio_common: protect register write overflow

[Spencer Olson]

On Tue, Oct 2, 2018 at 11:32 AM Greg Kroah-Hartman
<gregkh at linuxfoundation.org> wrote:
>
> On Wed, Sep 19, 2018 at 10:17:19AM -0600, Spencer E. Olson wrote:
> > Fixes two problems introduced as early as
> > commit 03aef4b6dc12  ("Staging: comedi: add ni_mio_common code"):
> > (1) Ensures that the last four bits of NISTC_RTSI_TRIGB_OUT_REG register is
> >     not unduly overwritten on e-series devices.  On e-series devices, the
> >     first three of the last four bits are reserved.  The last bit defines
> >     the output selection of the RGOUT0 pin, otherwise known as
> >     RTSI_Sub_Selection.  For m-series devices, these last four bits are
> >     indeed used as the output selection of the RTSI7 pin (and the
> >     RTSI_Sub_Selection bit for the RGOUT0 pin is moved to the
> >     RTSI_Trig_Direction register.
> > (2) Allows all 4 RTSI_BRD lines to be treated as valid sources for RTSI
> >     lines.
> >
> > This patch also cleans up the ni_get_rtsi_routing command for readability.
> >
> > Fixes: 03aef4b6dc12  ("Staging: comedi: add ni_mio_common code")
> > Signed-off-by: Spencer E. Olson <olsonse at umich.edu>
> > Reviewed-by: Ian Abbott <abbotti at mev.co.uk>
> > Cc: stable <stable at vger.kernel.org>
> > ---
> > I thought I had already submitted this patch a while ago...  Whoops.
> >  .../staging/comedi/drivers/ni_mio_common.c    | 24 +++++++++++++------
> >  1 file changed, 17 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
> > index 4dee2fc37aed..4d0d0621780e 100644
> > --- a/drivers/staging/comedi/drivers/ni_mio_common.c
> > +++ b/drivers/staging/comedi/drivers/ni_mio_common.c
> > @@ -4980,7 +4980,10 @@ static int ni_valid_rtsi_output_source(struct comedi_device *dev,
> >       case NI_RTSI_OUTPUT_G_SRC0:
> >       case NI_RTSI_OUTPUT_G_GATE0:
> >       case NI_RTSI_OUTPUT_RGOUT0:
> > -     case NI_RTSI_OUTPUT_RTSI_BRD_0:
> > +     case NI_RTSI_OUTPUT_RTSI_BRD(0):
> > +     case NI_RTSI_OUTPUT_RTSI_BRD(1):
> > +     case NI_RTSI_OUTPUT_RTSI_BRD(2):
> > +     case NI_RTSI_OUTPUT_RTSI_BRD(3):
> >               return 1;
> >       case NI_RTSI_OUTPUT_RTSI_OSC:
> >               return (devpriv->is_m_series) ? 1 : 0;
> > @@ -5001,11 +5004,18 @@ static int ni_set_rtsi_routing(struct comedi_device *dev,
> >               devpriv->rtsi_trig_a_output_reg |= NISTC_RTSI_TRIG(chan, src);
> >               ni_stc_writew(dev, devpriv->rtsi_trig_a_output_reg,
> >                             NISTC_RTSI_TRIGA_OUT_REG);
> > -     } else if (chan < 8) {
> > +     } else if (chan < NISTC_RTSI_TRIG_NUM_CHAN(devpriv->is_m_series)) {
> >               devpriv->rtsi_trig_b_output_reg &= ~NISTC_RTSI_TRIG_MASK(chan);
> >               devpriv->rtsi_trig_b_output_reg |= NISTC_RTSI_TRIG(chan, src);
> >               ni_stc_writew(dev, devpriv->rtsi_trig_b_output_reg,
> >                             NISTC_RTSI_TRIGB_OUT_REG);
> > +     } else if (chan != NISTC_RTSI_TRIG_OLD_CLK_CHAN) {
> > +             /* probably should never reach this, since the
> > +              * ni_valid_rtsi_output_source above errors out if chan is too
> > +              * high
> > +              */
> > +             dev_err(dev->class_dev, "%s: unknown rtsi channel\n", __func__);
>
> This patch breaks the build very badly.  Always test-build your patches
> at the very least :(
>
> greg k-h

I have been test building this with at least a fairly recent
staging-next rebase (rebase a week or two ago).  I'll rebase again and
check this out....