From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30950C433EF for ; Mon, 30 May 2022 14:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242512AbiE3OhY (ORCPT ); Mon, 30 May 2022 10:37:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242326AbiE3OSr (ORCPT ); Mon, 30 May 2022 10:18:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21FD61207DA; Mon, 30 May 2022 06:49:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3122160F14; Mon, 30 May 2022 13:48:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DE54C36AE7; Mon, 30 May 2022 13:48:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653918515; bh=1oaoX4ok9yeMVtkHfkvusLYM5Kis7pHtPy11PUfzcqY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UZr5hZZkwh1MBLbeC5nBcAe+Vdj/LdnYJi3bVQNkzZEeLgvLa1Ko2jWT11JSSZq9V 9LIUJx+d46Fwr7rSejc+cdBw/t6ib5kX8sB0xqoVY+0/4/8O2t14GcbovPpU4Qky/I GNFqR3p+uCdOl/Vu/NLc3IcnL3iAgbfAqV9+b76cfQI5jgpk2PhVjdth4d0Jw5Nyn9 bYW158sW0pAuHHFbNzX8lNBdcWyLfbBEJT22//9Z0b+cEYs8hnMAGJW/U+Gg37+TbC At/D05VAjXXBo0X9bLpLIw5nR7ON0Xyuktsm3L1naIw+5aHos1CXDXUOnSIEzVEhcA +DOTO2DMXd5CQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Heiko Carstens , Thomas Richter , Sven Schnelle , Sasha Levin , gor@linux.ibm.com, agordeev@linux.ibm.com, vschneid@redhat.com, linux-s390@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 35/55] s390/preempt: disable __preempt_count_add() optimization for PROFILE_ALL_BRANCHES Date: Mon, 30 May 2022 09:46:41 -0400 Message-Id: <20220530134701.1935933-35-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220530134701.1935933-1-sashal@kernel.org> References: <20220530134701.1935933-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Heiko Carstens [ Upstream commit 63678eecec57fc51b778be3da35a397931287170 ] gcc 12 does not (always) optimize away code that should only be generated if parameters are constant and within in a certain range. This depends on various obscure kernel config options, however in particular PROFILE_ALL_BRANCHES can trigger this compile error: In function ‘__atomic_add_const’, inlined from ‘__preempt_count_add.part.0’ at ./arch/s390/include/asm/preempt.h:50:3: ./arch/s390/include/asm/atomic_ops.h:80:9: error: impossible constraint in ‘asm’ 80 | asm volatile( \ | ^~~ Workaround this by simply disabling the optimization for PROFILE_ALL_BRANCHES, since the kernel will be so slow, that this optimization won't matter at all. Reported-by: Thomas Richter Reviewed-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/include/asm/preempt.h | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/s390/include/asm/preempt.h b/arch/s390/include/asm/preempt.h index b5ea9e14c017..3dcd8ab3db73 100644 --- a/arch/s390/include/asm/preempt.h +++ b/arch/s390/include/asm/preempt.h @@ -52,10 +52,17 @@ static inline bool test_preempt_need_resched(void) static inline void __preempt_count_add(int val) { - if (__builtin_constant_p(val) && (val >= -128) && (val <= 127)) - __atomic_add_const(val, &S390_lowcore.preempt_count); - else - __atomic_add(val, &S390_lowcore.preempt_count); + /* + * With some obscure config options and CONFIG_PROFILE_ALL_BRANCHES + * enabled, gcc 12 fails to handle __builtin_constant_p(). + */ + if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES)) { + if (__builtin_constant_p(val) && (val >= -128) && (val <= 127)) { + __atomic_add_const(val, &S390_lowcore.preempt_count); + return; + } + } + __atomic_add(val, &S390_lowcore.preempt_count); } static inline void __preempt_count_sub(int val) -- 2.35.1