From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754603AbdJSNyg (ORCPT ); Thu, 19 Oct 2017 09:54:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48842 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754499AbdJSNyd (ORCPT ); Thu, 19 Oct 2017 09:54:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Guenter Roeck , Sasha Levin Subject: [PATCH 3.18 15/27] watchdog: kempld: fix gcc-4.3 build Date: Thu, 19 Oct 2017 15:49:21 +0200 Message-Id: <20171019134845.642289135@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171019134844.523725420@linuxfoundation.org> References: <20171019134844.523725420@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann [ Upstream commit 3736d4eb6af37492aeded7fec0072dedd959c842 ] gcc-4.3 can't decide whether the constant value in kempld_prescaler[PRESCALER_21] is built-time constant or not, and gets confused by the logic in do_div(): drivers/watchdog/kempld_wdt.o: In function `kempld_wdt_set_stage_timeout': kempld_wdt.c:(.text.kempld_wdt_set_stage_timeout+0x130): undefined reference to `__aeabi_uldivmod' This adds a call to ACCESS_ONCE() to force it to not consider it to be constant, and leaves the more efficient normal case in place for modern compilers, using an #ifdef to annotate why we do this hack. Signed-off-by: Arnd Bergmann Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/watchdog/kempld_wdt.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/watchdog/kempld_wdt.c +++ b/drivers/watchdog/kempld_wdt.c @@ -140,12 +140,19 @@ static int kempld_wdt_set_stage_timeout( unsigned int timeout) { struct kempld_device_data *pld = wdt_data->pld; - u32 prescaler = kempld_prescaler[PRESCALER_21]; + u32 prescaler; u64 stage_timeout64; u32 stage_timeout; u32 remainder; u8 stage_cfg; +#if GCC_VERSION < 40400 + /* work around a bug compiling do_div() */ + prescaler = READ_ONCE(kempld_prescaler[PRESCALER_21]); +#else + prescaler = kempld_prescaler[PRESCALER_21]; +#endif + if (!stage) return -EINVAL;