From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60299 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751803AbbLJLJz (ORCPT ); Thu, 10 Dec 2015 06:09:55 -0500 Date: Thu, 10 Dec 2015 12:08:02 +0100 From: Stanislaw Gruszka To: Arnd Bergmann Cc: Kalle Valo , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, nico@linaro.org Subject: Re: [PATCH] iwlegacy: mark il_adjust_beacon_interval as noinline Message-ID: <20151210110801.GA2010@redhat.com> (sfid-20151210_121104_396493_D596562D) References: <36263581.L8412YxJjp@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <36263581.L8412YxJjp@wuerfel> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Dec 09, 2015 at 05:42:41PM +0100, Arnd Bergmann wrote: > With the new optimized do_div() code, some versions of gcc > produce obviously incorrect code that leads to a link error > in iwlegacy/common.o: > > drivers/built-in.o: In function `il_send_rxon_timing': > :(.text+0xa6b4d4): undefined reference to `____ilog2_NaN' > :(.text+0xa6b4f0): undefined reference to `__aeabi_uldivmod' > > In a few thousand randconfig builds, I have seen this problem > a couple of times in this file, but never anywhere else in the > kernel, so we can try to work around this in the only file > that shows the behavior, by marking the il_adjust_beacon_interval > function as noinline, which convinces gcc to use the unoptimized > do_div() all the time. I don't think this is good way to "fix" the issue, but also have nothing against to this particular change. Acked-by: Stanislaw Gruszka