From owner-freebsd-arch@FreeBSD.ORG Wed Feb 5 22:13:06 2014 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 042C3955; Wed, 5 Feb 2014 22:13:06 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id CBFCF10BD; Wed, 5 Feb 2014 22:13:05 +0000 (UTC) Received: from ralph.baldwin.cx (pool-173-70-85-31.nwrknj.fios.verizon.net [173.70.85.31]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id C0BADB99A; Wed, 5 Feb 2014 17:13:04 -0500 (EST) From: John Baldwin To: Ian Lepore Subject: Re: Malloc alignment in libstand / loader(8) Date: Wed, 05 Feb 2014 15:38:34 -0500 Message-ID: <2263843.rxdRK42Wk4@ralph.baldwin.cx> User-Agent: KMail/4.10.5 (FreeBSD/10.0-STABLE; KDE/4.10.5; amd64; ; ) In-Reply-To: <1391630829.1196.31.camel@revolution.hippie.lan> References: <1391576134.1196.21.camel@revolution.hippie.lan> <2882663.sRzekugaiD@ralph.baldwin.cx> <1391630829.1196.31.camel@revolution.hippie.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Wed, 05 Feb 2014 17:13:04 -0500 (EST) Cc: freebsd-arch@freebsd.org X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Feb 2014 22:13:06 -0000 On Wednesday, February 05, 2014 01:07:09 PM Ian Lepore wrote: > On Wed, 2014-02-05 at 08:29 -0500, John Baldwin wrote: > > On Tuesday, February 04, 2014 09:55:34 PM Ian Lepore wrote: > > > On newer ARM chips, the device drivers used by loader(8) require that > > > I/O buffers be aligned on cache line sized boundaries. The drivers are > > > part of u-boot which serves as a sort of load-time bios. > > > > > > Attached is a patch that sets the malloc alignment in libstand to 64 > > > bytes when compiled on ARM, and leaves it at 16 bytes for all other > > > platforms. If there are no objections I'd like to commit this soon. > > > > > > I've tested this on ARM, but have no way to test it on other platforms. > > > The changes should be a no-op on other platforms. > > > > I think this looks fine, but perhaps use CTASSERT() instead of rolling > > your > > own? (I would say to use _Static_assert(), but I don't think that works > > with our old GCC) > > I wasn't sure if it's a good idea to #include in the libstand > environment, since it has declarations for a lot of stuff. I looked at > what's in systm.h and then hand-replicated what seemed like the most > generic of the choices. That's fair. -- John Baldwin