Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752870AbbBYRDB (ORCPT ); Wed, 25 Feb 2015 12:03:01 -0500 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:34859 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751852AbbBYRDA (ORCPT ); Wed, 25 Feb 2015 12:03:00 -0500 Date: Wed, 25 Feb 2015 17:02:50 +0000 From: Russell King - ARM Linux To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Pranith Kumar , open list Subject: Re: [RFC PATCH] arm: asm/cmpxchg.h: Add support half-word xchg() Message-ID: <20150225170250.GD8656@n2100.arm.linux.org.uk> References: <1424878581-11701-1-git-send-email-bobby.prani@gmail.com> <3465519.0ga9zC7F7b@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3465519.0ga9zC7F7b@wuerfel> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1642 Lines: 35 On Wed, Feb 25, 2015 at 04:58:35PM +0100, Arnd Bergmann wrote: > On Wednesday 25 February 2015 10:36:20 Pranith Kumar wrote: > > This patch adds support for a half-word xchg() for ARM using ldrexh/strexh > > instructions. It also fixes an asm comment for __cmpxchg2. > > > > Currently using a half-word xchg() results in the following splat on an ARMv7 > > machine. > > > > [ 45.833303] xchg: bad data size: pc 0xbe806020, ptr 0xeb18deee, size 2 > > [ 45.833324] ------------[ cut here ]------------ > > [ 45.837939] kernel BUG at /dvs/git/dirty/git-master_linux/kernel/arch/arm/kernel/traps.c:727! > > > > Signed-off-by: Pranith Kumar > > Unfortunately, the BUG message seems incomplete, can you reproduce this > with CONFIG_DEBUG_BUGVERBOSE enabled? That isn't because CONFIG_DEBUG_BUGVERBOSE isn't set. It's because the message author decided that the remainder of the kernel bug message wasn't useful to report. After all, it's just a load of hex numbers and symbolic information. Who would want that junk. (Some people really don't get this: we print stuff from the kernel because it gives _us_ useful information to debug problems like this, but because they don't understand it themselves, they decide they can omit it from their bug reports...) -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/