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 652F6C43334 for ; Tue, 7 Jun 2022 21:11:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357507AbiFGVLx (ORCPT ); Tue, 7 Jun 2022 17:11:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379872AbiFGVLI (ORCPT ); Tue, 7 Jun 2022 17:11:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 829D012B006; Tue, 7 Jun 2022 11:52:19 -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 ams.source.kernel.org (Postfix) with ESMTPS id 1389FB81FE1; Tue, 7 Jun 2022 18:52:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C6CEC385A2; Tue, 7 Jun 2022 18:52:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654627936; bh=g7XB8B2hXhx0t6vm3lGhWMstRlw7oJH8/lHkhtWU6kk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rRT0vJ+c/XgHqfFioQALDmDfPJpEYcoO34K63Knr5Z0lKOV/L2dqkv5f8ooku/pO1 QcWxiPXHLoOkN1STlmnmf8Ee8Jmt3uYXptWaBkuiXEQWOtX5t4K+xOTFzZc7v9h0Hq RpG1QIqNzSWsSzeXdVQTbRoLtdi+ZvQowG6iZTGI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Richter , Sven Schnelle , Heiko Carstens , Sasha Levin Subject: [PATCH 5.18 146/879] s390/preempt: disable __preempt_count_add() optimization for PROFILE_ALL_BRANCHES Date: Tue, 7 Jun 2022 18:54:24 +0200 Message-Id: <20220607165006.941950313@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607165002.659942637@linuxfoundation.org> References: <20220607165002.659942637@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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 d9d5350cc3ec..bf15da0fedbc 100644 --- a/arch/s390/include/asm/preempt.h +++ b/arch/s390/include/asm/preempt.h @@ -46,10 +46,17 @@ 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