From owner-freebsd-arm@FreeBSD.ORG  Sun Mar  8 21:09:09 2015
Return-Path: <owner-freebsd-arm@FreeBSD.ORG>
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 A4D26EF1
 for <freebsd-arm@freebsd.org>; Sun,  8 Mar 2015 21:09:09 +0000 (UTC)
Received: from phabric-backend.isc.freebsd.org
 (phabric-backend.isc.freebsd.org [IPv6:2001:4f8:3:ffe0:406a:0:50:2])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 7CDC9836
 for <freebsd-arm@freebsd.org>; Sun,  8 Mar 2015 21:09:09 +0000 (UTC)
Received: from phabric-backend.isc.freebsd.org
 (phabric-backend.isc.freebsd.org [127.0.1.5])
 by phabric-backend.isc.freebsd.org (8.14.9/8.14.9) with ESMTP id
 t28L99Cr013036
 for <freebsd-arm@freebsd.org>; Sun, 8 Mar 2015 21:09:09 GMT
 (envelope-from root@phabric-backend.isc.freebsd.org)
Received: (from root@localhost)
 by phabric-backend.isc.freebsd.org (8.14.9/8.14.9/Submit) id t28L99L2013035;
 Sun, 8 Mar 2015 21:09:09 GMT (envelope-from root)
Date: Sun, 8 Mar 2015 21:09:09 +0000
To: freebsd-arm@freebsd.org
From: "imp (Warner Losh)" <phabric-noreply@FreeBSD.org>
Subject: [Differential] [Updated] D2017: Allow to disable alignment faults in
 the kernel configuration file
Message-ID: <3cec6b9b22f43a47f04341ad94bed44c@localhost.localdomain>
X-Priority: 3
Thread-Topic: D2017: Allow to disable alignment faults in the kernel
 configuration file
X-Herald-Rules: none
X-Phabricator-To: <PHID-USER-6m5mo2kjikkzyd33ld4n>
X-Phabricator-To: <PHID-USER-yhwnadxnjthofqelhkdx>
X-Phabricator-To: <PHID-USER-pns6zgllnr6ze4h7ms3o>
X-Phabricator-To: <PHID-USER-q5lmute3rwskeizvu5gf>
X-Phabricator-Cc: <PHID-MLST-stsrni3uozki6w7zubvy>
In-Reply-To: <differential-rev-PHID-DREV-phrk75eo7uo5meyd5xay-req@FreeBSD.org>
References: <differential-rev-PHID-DREV-phrk75eo7uo5meyd5xay-req@FreeBSD.org>
Thread-Index: M2IwYjY0ZDAxMWY3ZTNlM2Y4OWM0M2JjYjUzIFT8unU=
X-Phabricator-Sent-This-Message: Yes
X-Mail-Transport-Agent: MetaMTA
X-Auto-Response-Suppress: All
X-Phabricator-Mail-Tags: <differential-reviewers>, <differential-comment>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset="utf-8"
X-BeenThere: freebsd-arm@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: "Porting FreeBSD to ARM processors." <freebsd-arm.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-arm>,
 <mailto:freebsd-arm-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arm/>
List-Post: <mailto:freebsd-arm@freebsd.org>
List-Help: <mailto:freebsd-arm-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arm>,
 <mailto:freebsd-arm-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 08 Mar 2015 21:09:09 -0000

imp added a comment.

>>! In D2017#6, @ian wrote:
> I think if this option is set we may need to notice that and set __NO_STRICT_ALIGNMENT accordingly (I'm not sure how/where that gets set).

__NO_STRICT_ALIGNMENT gets set in machine/_types.h right now.

However, it can not be set based on kernel options because it is shared with user land. It is supposed
to describe all users of the architecture. Since we have no clue what kernel will be used, we'd have
to assume all or nothing based on, say, the architecture level.

I'm not familiar enough with all the implications at the hardware level to know what ARM32_DISABLE_ALIGNMENT_FAULTS would really do, so I can't say if making it default is a good idea or not.

REVISION DETAIL
  https://reviews.freebsd.org/D2017

To: zbb, ian, andrew, imp
Cc: freebsd-arm