> -----Original Message----- > From: Andy Shevchenko [mailto:andy.shevchenko@xxxxxxxxx] > Sent: Monday, September 25, 2017 1:04 PM > To: Pali Rohár <pali.rohar@xxxxxxxxx> > Cc: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; dvhart@xxxxxxxxxxxxx; > LKML <linux-kernel@xxxxxxxxxxxxxxx>; Platform Driver <platform-driver- > x86@xxxxxxxxxxxxxxx>; quasisec@xxxxxxxxxx > Subject: Re: [PATCH 06/12] platform/x86: dell-wmi-smbios: Add a sysfs interface > for SMBIOS tokens > > On Mon, Sep 25, 2017 at 7:23 PM, Pali Rohár <pali.rohar@xxxxxxxxx> wrote: > > On Thursday 21 September 2017 08:57:11 Mario Limonciello wrote: > >> Currently userspace tools can access system tokens via the dcdbas > >> kernel module and a SMI call that will cause the platform to execute > >> SMM code. > >> > >> With a goal in mind of deprecating the dcdbas kernel module a different > >> method for accessing these tokens from userspace needs to be created. > >> > >> This is intentionally marked to only be readable as root as it can > >> contain sensitive information about the platform's configuration. > > > > Darren, Andy, any comments? I'm not quite sure if such API is suitable > > for long term in kernel. > > I would try to avoid sysfs interfaces for some particular devices. > Besides we are creating a character device. Would it be suitable there? If the character device having 2 different ioctls for different needs is acceptable I'm happy to adjust the series to do this instead. > > > Basically tokens are list of tuples <id, location, value> with > > possibility to active them, right? > > I didn't add a way to activate them through this, it was only for reading purpose. Activating them should be possible through the SMBIOS calling interface though. > > Does not kernel have some better API for it? > > I think the best what kernel may provide is a CSV-like format with or > without title line and different delimiter (TAB/space/etc). > > > > > Also, keep in mind security aspect of tokens. They represent e.g. boot > > order priority or enable/disable some machine peripheral. > > For IOCTLs we may use capabilities. > In sysfs case we may zero output based on capabilities or some other factors. > Can you recommend what capabilities you would prefer to see this based upon?
