From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [GIT PULL] Device tree updates for v3.12 Date: Tue, 10 Sep 2013 18:19:39 -0400 Message-ID: <20130910221939.GC11063@thunk.org> References: <522F97EF.5050303@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <522F97EF.5050303@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: Linus Torvalds , Tim Bird , Grant Likely , Linux Kernel Mailing List , "devicetree@vger.kernel.org" , Anton Blanchard List-Id: devicetree@vger.kernel.org On Tue, Sep 10, 2013 at 05:06:39PM -0500, Rob Herring wrote: > > If I recall correctly, somebody said that things like ethernet MAC > > addresses etc sometimes come from DT. Is my memory going, or is that > > true but very rare? > > It is true and fairly common. You can also have serial numbers in the > DT, but that is more rare. The bootloader will also add the kernel > command line, initrd start and end addresses. Stuff which is common across a large number of devices is rather less useful to merge in. Is there some fixed way that things like serial numbers and MAC addresses are tagged as such in the device tree? Those are really the interesting bits to pass to add_device_randomness(). What we want is stuff which is unique to the device --- SP 800-90 (the NIST SPEC on Secure Random Number Generators) refers to this as "personalization strings". - Ted