From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4DAF7BEE for ; Wed, 25 Oct 2017 10:18:17 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id DBE144CC for ; Wed, 25 Oct 2017 10:18:16 +0000 (UTC) Date: Wed, 25 Oct 2017 13:18:13 +0300 From: Leon Romanovsky To: Bart Van Assche , "greg@kroah.com" Message-ID: <20171025101813.GP16127@mtr-leonro.local> References: <1508924843.4165.6.camel@wdc.com> <20171025095403.GA19080@kroah.com> <1508926018.4165.12.camel@wdc.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Sk71+Upln2BLuDmg" Content-Disposition: inline In-Reply-To: <1508926018.4165.12.camel@wdc.com> Cc: "ksummit-discuss@lists.linuxfoundation.org" Subject: Re: [Ksummit-discuss] [TECH TOPIC] How to encourage driver authors to annotate integer endianness properly List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --Sk71+Upln2BLuDmg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Oct 25, 2017 at 10:06:59AM +0000, Bart Van Assche wrote: > On Wed, 2017-10-25 at 11:54 +0200, Greg KH wrote: > > On Wed, Oct 25, 2017 at 09:47:25AM +0000, Bart Van Assche wrote: > > > Hello Ted, > > > > > > As you most likely know endianness annotations like __be32 can be verified > > > by the static source code analyzer called sparse. These annotations are a > > > big help to verify whether endianness conversions in drivers are correct > > > (e.g. be32_to_cpu()). However, many driver authors either are not familiar > > > with sparse or do not use it to verify their work. I think we need a way > > > to encourage driver authors to pay attention to endianness annotations, > > > e.g. by letting the zero-day kernel test infrastructure verify endianness > > > annotations. Please consider to add this topic to the kernel summit agenda. > > > > Driver subsystem maintainers should know this, and sparse reports should > > be simple to run and notice these issues. If you know of a subsystem > > that is not paying attention to this, please let those maintainers know > > and send patches to resolve the issues :) > > Hi Greg, > > A significant challenge is that for several drivers (e.g. drivers/scsi/qla2xxx > and drivers/infiniband/hw/nes) fixing the endianness annotations is so hard > that only the driver authors can make these drivers endianness clean. Three > challenges that have been encountered while trying to make drivers endianness > clean are: > - Some driver authors use a single variable to store both cpu-endian and big > endian data. > - Endianness bugs - using a big endian integer where a cpu endian number > should have been used or vice versa. > - The definitive resource for the endianness format is the firmware > documentation. For many kernel drivers the firmware documentation is either > not available or only available under NDA. It is e very appealing to fix the driver endianness issues without involving driver authors, but it is not feasible without their cooperation and it is not always possible especially for not-active drivers. Thanks > > Bart. > _______________________________________________ > Ksummit-discuss mailing list > Ksummit-discuss@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/ksummit-discuss --Sk71+Upln2BLuDmg Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAlnwZOUACgkQ5GN7iDZy WKcSfw/9FSPXgLLIKkOIr4mn7hJAxMi7LaZlAyoLs8w226rLtETbnqSjNSL4/Shd wngPnbDvNsca+xPIK75hScs/8h+BS/BQ0sHwuwPd8mSCMS3i60PzeVFo0vwacoyQ h5LoGN4+RLCK/3GGJ8FQexEfin5tiot+X3efNs5xhmLuGJeNJeV6zyuyu+ablu5C 4+CEVMaelp9sBwi6NjW0cX8qsylXERoGwwRslq18jCn/WbAakhj88TkpGBpw8CGl R34f89EtUdBLOxKkRCOG+c+XNblUHB+zSujMetVn1ylaECu4688B1vqiaNJ10dji neGxjmCeSwH2uLL4KnKQuR2TdIs/f/AmNda5kMTtLXTjv/GaeaDXGFTSRNS+rzYA Ln1Y9PPHc7TgKP0VewCW7DEHhoEiwPXllGdqL60TuVrSahd3vCZjOL2x98M0js34 w2msrTL0nEPZBAfwOGIJCSu/LVJbKg6Zi6xXBeT5WW2jYUsiVTqxBqKKc+B8QavU BGmGz2DJ0M+Lq8T/GLIeO6kjYN1rQitvwVsRVNeUyFS27A09u5/Cc0dP53/N8DRX 31OAriD6d22YLuFHeRGIGSs03yt7IQKzCIQlSroE7SsyY+oYlIhKVoQ2R++jTPSK brjlwoUE4HjNI8oI/bsylKwnhXAwzYh3UjXIyE8heRtiJehuCyA= =BjOT -----END PGP SIGNATURE----- --Sk71+Upln2BLuDmg--