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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80E78C433EF for ; Sun, 19 Sep 2021 02:02:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F9D2610CF for ; Sun, 19 Sep 2021 02:02:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232470AbhISCDj (ORCPT ); Sat, 18 Sep 2021 22:03:39 -0400 Received: from conssluserg-04.nifty.com ([210.131.2.83]:42446 "EHLO conssluserg-04.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230377AbhISCDi (ORCPT ); Sat, 18 Sep 2021 22:03:38 -0400 Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) (authenticated) by conssluserg-04.nifty.com with ESMTP id 18J220fs028187; Sun, 19 Sep 2021 11:02:00 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-04.nifty.com 18J220fs028187 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1632016920; bh=Z/gNxIq+bDVsIzi7WYm/lUdYSrE6EljYQaYBdU/xrxE=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=HSEPVfsG+udftoyE19f0nHM6NcHFPq3gJIVhvRXtqThMQF59ggtQO/HCzqlZZIgQ0 oS9mYGl27M82beRh2ss3EhHJY8s+bdjmaY9+sA7+N1NbCJ8uUFsHFKY+t5yXZ0HA45 aTuZFxlAVsbwcdEFOLA1j7Joj3K+nI9LwO2ZZVXbwiALu3vriYus+vN/SKqFfeIlj2 /+q0UqMQhQF72czXeO5W+vCGcjqu0458hfjSf6fA2JctXzGdqY+UsQNhcy7748DLNe SP/VGOWifGlzki8rHDPTwD9waoprKyZbNv3gmwx13uH/I4rHD55YBTsDBH6kPx6rpz N93MZqSUjdmJg== X-Nifty-SrcIP: [209.85.215.169] Received: by mail-pg1-f169.google.com with SMTP id q68so13733502pga.9; Sat, 18 Sep 2021 19:02:00 -0700 (PDT) X-Gm-Message-State: AOAM530y+i/HLAcAWyAxYytwz/6wz+BPfyK3/MvIX/znb2BiymxDiIBL DGN/iK58aVWi12OCy1qLklFBS389xivYei2b88Q= X-Google-Smtp-Source: ABdhPJyw1BAb4i9nakU7J7GTQ5NMugRyYo7+seI20mR/j8MquU+znpaVKlN6fnF1fNFhjEZHUIOU3jifNrszBT+QZVo= X-Received: by 2002:a65:40c4:: with SMTP id u4mr17266657pgp.186.1632016919668; Sat, 18 Sep 2021 19:01:59 -0700 (PDT) MIME-Version: 1.0 References: <20210916184017.1881473-1-nathan@kernel.org> <20210916184017.1881473-2-nathan@kernel.org> In-Reply-To: <20210916184017.1881473-2-nathan@kernel.org> From: Masahiro Yamada Date: Sun, 19 Sep 2021 11:01:22 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 1/2] x86/build: Do not add -falign flags unconditionally for clang To: Nathan Chancellor Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , X86 ML , "H. Peter Anvin" , Nick Desaulniers , Linux Kernel Mailing List , Linux Kbuild mailing list , llvm@lists.linux.dev, kernel test robot , Borislav Petkov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Fri, Sep 17, 2021 at 3:42 AM Nathan Chancellor wrote: > > clang does not support -falign-jumps and only recently gained support > for -falign-loops. When one of the configuration options that adds these > flags is enabled, clang warns and all cc-{disable-warning,option} that > follow fail because -Werror gets added to test for the presence of this > warning: > > clang-14: warning: optimization flag '-falign-jumps=0' is not supported > [-Wignored-optimization-argument] > > To resolve this, add a couple of cc-option calls when building with > clang; gcc has supported these options since 3.2 so there is no point in > testing for their support. -falign-functions was implemented in clang-7, > -falign-loops was implemented in clang-14, and -falign-jumps has not > been implemented yet. > > Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/ > Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/ > Reported-by: kernel test robot > Reviewed-by: Nick Desaulniers > Acked-by: Borislav Petkov > Signed-off-by: Nathan Chancellor > --- > arch/x86/Makefile_32.cpu | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu > index e7355f8b51c2..94834c4b5e5e 100644 > --- a/arch/x86/Makefile_32.cpu > +++ b/arch/x86/Makefile_32.cpu > @@ -4,6 +4,12 @@ > > tune = $(call cc-option,-mtune=$(1),$(2)) > > +ifdef CONFIG_CC_IS_CLANG > +align := -falign-functions=0 $(call cc-option,-falign-jumps=0) $(call cc-option,-falign-loops=0) > +else > +align := -falign-functions=0 -falign-jumps=0 -falign-loops=0 > +endif > + > cflags-$(CONFIG_M486SX) += -march=i486 > cflags-$(CONFIG_M486) += -march=i486 > cflags-$(CONFIG_M586) += -march=i586 > @@ -19,11 +25,11 @@ cflags-$(CONFIG_MK6) += -march=k6 > # They make zero difference whatsosever to performance at this time. > cflags-$(CONFIG_MK7) += -march=athlon > cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon) > -cflags-$(CONFIG_MCRUSOE) += -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0 > -cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0 > +cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align) > +cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align) > cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586) > cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586) > -cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) -falign-functions=0 -falign-jumps=0 -falign-loops=0 > +cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align) > cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686) > cflags-$(CONFIG_MVIAC7) += -march=i686 > cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2) > > base-commit: a9086b878b7fd65894eb8cb1fa395dd469970566 > -- > 2.33.0 > Applied to linux-kbuild. Thanks. -- Best Regards Masahiro Yamada