From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: [PATCH 07/13] watchdog: kempld: fix gcc-4.3 build Date: Fri, 16 Dec 2016 11:56:28 +0100 Message-ID: <20161216105634.235457-8-arnd@arndb.de> References: <20161216105634.235457-1-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 0F01E405D6 for ; Fri, 16 Dec 2016 05:55:41 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nD2SCYrW9oBV for ; Fri, 16 Dec 2016 05:55:40 -0500 (EST) Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.73]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id B4066405E6 for ; Fri, 16 Dec 2016 05:55:39 -0500 (EST) In-Reply-To: <20161216105634.235457-1-arnd@arndb.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: linux-arch@vger.kernel.org Cc: Arnd Bergmann , kernel-build-reports@lists.linaro.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Russell King , Andrew Morton , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@vger.kernel.org List-Id: kvmarm@lists.cs.columbia.edu 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 --- drivers/watchdog/kempld_wdt.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c index 8e302d0e346c..3efa295ac627 100644 --- a/drivers/watchdog/kempld_wdt.c +++ b/drivers/watchdog/kempld_wdt.c @@ -140,12 +140,19 @@ static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data, 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; -- 2.9.0