From owner-freebsd-arm@FreeBSD.ORG Thu Feb 12 18:44:55 2015 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 610E21DD for ; Thu, 12 Feb 2015 18:44:55 +0000 (UTC) Received: from anacreon.physics.berkeley.edu (anacreon.Physics.Berkeley.EDU [128.32.117.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "anacreon.physics.wisc.edu", Issuer "anacreon.physics.wisc.edu" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 21437AFB for ; Thu, 12 Feb 2015 18:44:54 +0000 (UTC) Received: from anacreon.physics.berkeley.edu (localhost [127.0.0.1]) by anacreon.physics.berkeley.edu (8.14.9/8.14.9) with ESMTP id t1CIirsi071863; Thu, 12 Feb 2015 10:44:53 -0800 (PST) (envelope-from nwhitehorn@freebsd.org) Message-ID: <54DCF4A5.2020305@freebsd.org> Date: Thu, 12 Feb 2015 10:44:53 -0800 From: Nathan Whitehorn User-Agent: Mozilla/5.0 (X11; FreeBSD powerpc; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Warner Losh Subject: Re: FreeBSD/arm64 MACHINE/MACHINE_ARCH identification References: <607BF592-A09B-4DB4-9872-C9E63066AB57@bsdimp.com> <71E9C1B9-F819-420B-90A5-A36D58E71817@bsdimp.com> <228428CC-4042-4902-90A4-E7040F4BFFF5@bsdimp.com> <54DCE9B5.8040203@freebsd.org> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: freebsd-arm@freebsd.org X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Feb 2015 18:44:55 -0000 On 02/12/15 10:37, Warner Losh wrote: > >> On Feb 12, 2015, at 10:58 AM, Nathan Whitehorn >> wrote: >> >> On 02/12/15 09:15, Ed Maste wrote: >>>>> Oh - I don't care what directory Linux puts the kernel source >>>>> in, only what's reported by uname. As far as I can tell that >>>>> has always been aarch64 for uname -m. >>>> >>>> Traditionally in Linux, they have been a matched set. >>> >>> Ok, it appears they may have abandoned this. >>> >>>>> We might decide that "uname -m" has to be aarch64 to match >>>>> expectations of third-party software set by other operating >>>>> systems. If that in turn means we have to move the kernel >>>>> source, so be it. >>>> >>>> This one I’m not on board with. You’ve not made a compelling >>>> case for it yet. >>> >>> That's why I said "we might decide" -- I'm not sure myself. >>> >>> However, there's no backwards compatibility concern here, we've >>> never had a FreeBSD release that reports "arm64" for "uname -m". >>> There's no reason for us to prefer "arm64" if everyone else uses >>> "aarch64." Also, having arm64 for uname -m and aarch64 for uname >>> -p seems a bit odd. >> >> I would assume uname -m would be "arm", not "arm64". Unless there >> are fundamental platform differences you are baking in somehow, >> which I don't know. > > arm would be a pleasing outcome, but looking at his WIP tree, it > looks like it would be possible, but rather inconvenient to merge the > arm64 bits back under arm and make them conditional. > > Warner > > That's unfortunate. Among other things, it precludes easy use of cc -m32. So what is the long-term plan here? Is the new ARM port a new, legacy-free, version that should grow separate 32-bit support for new armv7 systems and then we abandon sys/arm to the ARMv5 stuff? Or are 32-bit and 64-bit ARM just going to live separate lives forever? -Nathan