From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 20 Feb 2008 13:04:07 +1100 From: David Gibson To: Jerry Van Baren Subject: Re: libfdt: More tests of NOP handling behaviour Message-ID: <20080220020407.GC18944@localhost.localdomain> References: <20080218050925.GH29975@localhost.localdomain> <47BB7FDB.3050809@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <47BB7FDB.3050809@gmail.com> Cc: linuxppc-dev@ozlabs.org, Jon Loeliger List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Feb 19, 2008 at 08:18:19PM -0500, Jerry Van Baren wrote: > Jon Loeliger wrote: > > So, like, the other day David Gibson mumbled: > >> In light of the recently discovered bug with NOP handling, this adds > >> some more testcases for NOP handling. Specifically, it adds a helper > >> program which will add a NOP tag after every existing tag in a dtb, > >> and runs the standard battery of tests over trees mangled in this way. > >> > >> For now, this does not add a NOP at the very beginning of the > >> structure block. This causes problems for libfdt at present, because > >> we assume in many places that the root node's BEGIN_NODE tag is at > >> offset 0. I'm still contemplating what to do about this (with one > >> option being simply to declare such dtbs invalid). > >> > >> Signed-off-by: David Gibson > > > > Applied. > > > > BTW, declaring DTBs with BEGIN_NODES not at offset 0 > > as invalid seems like a fine choice to me. > > > > jdl > > FWIIW, I vote ditto on declaring DTBs with BEGIN_NODES not at offset 0 > as invalid. The root being at offset 0 assumption is pretty well > entrenched and I cannot think of any reason to change it that would be > worth the effort. Well, it's actually not that hard to deal with. I've already been planning to add a helper function/macro which validates a node offset (something currently open-coded in a whole bunch of places). It would be fairly easy to make it skip over nops as well. But, likewise I can think of no reason that NOPs before the root node would be useful or likely to occur in practice. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson