linux-kernel - Re: [PATCH 2/6] platform/x86/intel/tpmi: Don't create devices for disabled features

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <84eafa2c-27e3-1a55-39df-edb4a87f5eb1@linux.intel.com>
Date:   Thu, 30 Nov 2023 16:33:00 +0200 (EET)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
cc:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>, markgross@...nel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        platform-driver-x86@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] platform/x86/intel/tpmi: Don't create devices for
 disabled features

On Thu, 30 Nov 2023, srinivas pandruvada wrote:

> On Thu, 2023-11-30 at 14:26 +0200, Ilpo Järvinen wrote:
> > On Tue, 28 Nov 2023, Srinivas Pandruvada wrote:
> > 
> > > If some TPMI features are disabled, don't create auxiliary devices.
> > > In
> > > this way feature drivers will not load.
> > > 
> > > While creating auxiliary devices, call tpmi_read_feature_status()
> > > to
> > > check feature state and return if the feature is disabled without
> > > creating a device.
> > > 
> > > Signed-off-by: Srinivas Pandruvada
> > > <srinivas.pandruvada@...ux.intel.com>
> > > ---
> > >  drivers/platform/x86/intel/tpmi.c | 10 +++++++++-
> > >  1 file changed, 9 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/platform/x86/intel/tpmi.c
> > > b/drivers/platform/x86/intel/tpmi.c
> > > index c89aa4d14bea..4edaa182db04 100644
> > > --- a/drivers/platform/x86/intel/tpmi.c
> > > +++ b/drivers/platform/x86/intel/tpmi.c
> > > @@ -604,9 +604,17 @@ static int tpmi_create_device(struct
> > > intel_tpmi_info *tpmi_info,
> > >         struct intel_vsec_device *vsec_dev = tpmi_info->vsec_dev;
> > >         char feature_id_name[TPMI_FEATURE_NAME_LEN];
> > >         struct intel_vsec_device *feature_vsec_dev;
> > > +       struct tpmi_feature_state feature_state;
> > >         struct resource *res, *tmp;
> > >         const char *name;
> > > -       int i;
> > > +       int i, ret;
> > > +
> > > +       ret = tpmi_read_feature_status(tpmi_info, pfs-
> > > >pfs_header.tpmi_id, &feature_state);
> > > +       if (ret)
> > > +               return ret;
> > > +
> > > +       if (!feature_state.enabled)
> > > +               return -EOPNOTSUPP;
> > 
> > -ENODEV sounds more appropriate.  
>
> The -EOPNOTSUPP is returned matching the next return statement, which
> causes to continue to create devices which are supported and not
> disabled. Any other error is real device creation will causes driver
> modprobe to fail.

Oh, I see... I didn't look that deep into the code during my review
(perhaps note that down into the commit message?).

-- 
 i.