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=-19.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 941D7C433FF for ; Mon, 12 Aug 2019 17:36:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F9512067D for ; Mon, 12 Aug 2019 17:36:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RsNkwjci" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726506AbfHLRgI (ORCPT ); Mon, 12 Aug 2019 13:36:08 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:41225 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726267AbfHLRgI (ORCPT ); Mon, 12 Aug 2019 13:36:08 -0400 Received: by mail-pg1-f196.google.com with SMTP id x15so39495221pgg.8 for ; Mon, 12 Aug 2019 10:36:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oZi4p9sU++IMNyLOoMu4O4MSpldoBC3la4O/D+JmVeE=; b=RsNkwjciAZJFroOX5ILBuBvMy8TWcIT9hJzrTA5xuOZfMYJaav94/bNa1G1AZHA/sx IqeuX0m5wrq1olWYnCUFdWcRs4HHNmD+fSaxGCDngxV9gs9hEaGvpwiel6l6FYROI+wM b2h/J/0MtTn4wk+24P+lye5PvT7SR216V5ztbRz1yijbJD2TeXZKy39Wwf+AkV8DYbM0 CP6fjXz/iairhkQqUorj+Ear31cpwrY8D8/ls28sODMfPbYKCYDBl2dAo83EtHCePTLH MGmTVzL/6+j8BOjr0vRr/sKO1HKHpXTj0Kqk+R5o3T3ezXSVTGqzUJFXtYU7FXUZdbq9 iK5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oZi4p9sU++IMNyLOoMu4O4MSpldoBC3la4O/D+JmVeE=; b=VrPlIDqgBj7VcqBkPZNhPa4lzAksthUTElJqJ00qyJbal581K9WOe2d+WeFe5cWE99 CAJugBqaOQMBHjVPC5VhZfmu/Hq5N+UNcwJuN+7aNmD9cpHc/gVSgmL8i9Sc4cefvT/n MbS3fivVmgdi34nmdiVD2Mp1o7Om1+gcFaTKG9Nmr42MUtWJxq087n9RZIG2aUhGeLQA qvtpXxAEF9U/D0NQkznUc4HCV6kaZSzQkJ1bV60l/FtbR4gHuY8tolkNxX0c5HfxQhms lGoxWo+L+Ch8MIrnJHz2vMe/r7VFzhs2nGemfLIhbxzqfzt8smm7NJQFIHGNaO5tQ7sm e7Og== X-Gm-Message-State: APjAAAW0rrap8Ylt82SebGa/C117x6QIG9DccZCpHlf9hxaHqG5Aac6M SOrq+qV6vyPecm/gfqP1M2Nq+QWSN/gHG+w0252xeA== X-Google-Smtp-Source: APXvYqy2zouhlUGYS7Kh1lajVcXBTrIvaZyDmn96K5pB0TaQUQP3OryMKFONA/xS83RgDSxvOsb01vVyUXq5xlXLvmE= X-Received: by 2002:a63:f94c:: with SMTP id q12mr30736518pgk.10.1565631367302; Mon, 12 Aug 2019 10:36:07 -0700 (PDT) MIME-Version: 1.0 References: <20190812023214.107817-1-natechancellor@gmail.com> In-Reply-To: <20190812023214.107817-1-natechancellor@gmail.com> From: Nick Desaulniers Date: Mon, 12 Aug 2019 10:35:56 -0700 Message-ID: Subject: Re: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp To: Nathan Chancellor Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev , LKML , clang-built-linux , "# 3.4.x" Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sun, Aug 11, 2019 at 7:42 PM Nathan Chancellor wrote: > > Commit aea447141c7e ("powerpc: Disable -Wbuiltin-requires-header when > setjmp is used") disabled -Wbuiltin-requires-header because of a warning > about the setjmp and longjmp declarations. > > r367387 in clang added another diagnostic around this, complaining that > there is no jmp_buf declaration. > > In file included from ../arch/powerpc/xmon/xmon.c:47: > ../arch/powerpc/include/asm/setjmp.h:10:13: error: declaration of > built-in function 'setjmp' requires the declaration of the 'jmp_buf' > type, commonly provided in the header . > [-Werror,-Wincomplete-setjmp-declaration] > extern long setjmp(long *); > ^ > ../arch/powerpc/include/asm/setjmp.h:11:13: error: declaration of > built-in function 'longjmp' requires the declaration of the 'jmp_buf' > type, commonly provided in the header . > [-Werror,-Wincomplete-setjmp-declaration] > extern void longjmp(long *, long); > ^ > 2 errors generated. > > Take the same approach as the above commit by disabling the warning for > the same reason, we provide our own longjmp/setjmp function. > > Cc: stable@vger.kernel.org # 4.19+ > Link: https://github.com/ClangBuiltLinux/linux/issues/625 > Link: https://github.com/llvm/llvm-project/commit/3be25e79477db2d31ac46493d97eca8c20592b07 > Signed-off-by: Nathan Chancellor Thanks for the patch, Nathan. Reviewed-by: Nick Desaulniers > --- > > It may be worth using -fno-builtin-setjmp and -fno-builtin-longjmp > instead as it makes it clear to clang that we are not using the builtin > longjmp and setjmp functions, which I think is why these warnings are > appearing (at least according to the commit that introduced this waring). > > Sample patch: > https://github.com/ClangBuiltLinux/linux/issues/625#issuecomment-519251372 > > However, this is the most conservative approach, as I have already had > someone notice this error when building LLVM with PGO on tip of tree > LLVM. > > arch/powerpc/kernel/Makefile | 5 +++-- > arch/powerpc/xmon/Makefile | 5 +++-- > 2 files changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index ea0c69236789..44e340ed4722 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -5,8 +5,9 @@ > > CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"' > > -# Disable clang warning for using setjmp without setjmp.h header > -CFLAGS_crash.o += $(call cc-disable-warning, builtin-requires-header) > +# Avoid clang warnings about longjmp and setjmp built-ins (inclusion of setjmp.h and declaration of jmp_buf type) > +CFLAGS_crash.o += $(call cc-disable-warning, builtin-requires-header) \ > + $(call cc-disable-warning, incomplete-setjmp-declaration) > > ifdef CONFIG_PPC64 > CFLAGS_prom_init.o += $(NO_MINIMAL_TOC) > diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile > index f142570ad860..53f341391210 100644 > --- a/arch/powerpc/xmon/Makefile > +++ b/arch/powerpc/xmon/Makefile > @@ -1,8 +1,9 @@ > # SPDX-License-Identifier: GPL-2.0 > # Makefile for xmon > > -# Disable clang warning for using setjmp without setjmp.h header > -subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header) > +# Avoid clang warnings about longjmp and setjmp built-ins (inclusion of setjmp.h and declaration of jmp_buf type) > +subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header) \ > + $(call cc-disable-warning, incomplete-setjmp-declaration) > > GCOV_PROFILE := n > KCOV_INSTRUMENT := n > -- > 2.23.0.rc2 > -- Thanks, ~Nick Desaulniers