From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from condef-04.nifty.com (condef-04.nifty.com [202.248.20.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B62831856 for ; Sat, 2 Apr 2022 13:38:12 +0000 (UTC) Received: from conssluserg-02.nifty.com ([10.126.8.81])by condef-04.nifty.com with ESMTP id 232DW1sM023341 for ; Sat, 2 Apr 2022 22:32:01 +0900 Received: from mail-pf1-f174.google.com (mail-pf1-f174.google.com [209.85.210.174]) (authenticated) by conssluserg-02.nifty.com with ESMTP id 232DVpXO010107 for ; Sat, 2 Apr 2022 22:31:52 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-02.nifty.com 232DVpXO010107 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1648906312; bh=xOOUq32hUTZwQ6PgJmve8CWFa41o5uzRkpcTqar04RU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=vCXu70nRSHY2Lv6Bw5iUYKQi4NgIBNGXSOv3tNAM7uIraCCo4LTa/ywLh+ye+shXb nyeay6O+48FKit5/DNX5BWey6iI40BfoR2CRvJ9EJ5+1MXt/oOmH7AiGeFkXQ0CPLj overa1Km8ueTLcpp80BLIQS5+ythR9TwB7nORO0unED0bJyMNbIeDnSvXjmiPGLNNy rtWiVaxJCRfc+6O8PQvVYCjXyi9cVfCo2OyOiU1mPuDeADIf6nNevP14XZ80czHeJc j3n6MCL+YEvGPHblicFd6wB/EgXap3UVRfAnQwGa7ymZI7mzsiAUubppy7IoR+dbuJ oanKvBFDQVSfg== X-Nifty-SrcIP: [209.85.210.174] Received: by mail-pf1-f174.google.com with SMTP id p8so4968314pfh.8 for ; Sat, 02 Apr 2022 06:31:51 -0700 (PDT) X-Gm-Message-State: AOAM530FzKGI/HgZGfQ1HLAjQ+n5YCDLQ3d8Y3hceOvWk9r8lDd+uAhE xPHZTkm/pjonyWxW2XND7qHTgCyy5HViT5eKQ0A= X-Google-Smtp-Source: ABdhPJx4YYmusrB0Z5GeyAsnegUTZrEgkZTlTfMYeabO5lynAPEH3l4SbNCZnBVbE/nGUhMGQfWBqXQSL4kqhRfqwvQ= X-Received: by 2002:a63:ec47:0:b0:382:692a:dc04 with SMTP id r7-20020a63ec47000000b00382692adc04mr18906915pgj.352.1648906311008; Sat, 02 Apr 2022 06:31:51 -0700 (PDT) Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20220401201916.1487500-1-samitolvanen@google.com> <20220401201916.1487500-2-samitolvanen@google.com> In-Reply-To: <20220401201916.1487500-2-samitolvanen@google.com> From: Masahiro Yamada Date: Sat, 2 Apr 2022 22:31:03 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 1/3] kbuild: Change CFI_CLANG to depend on __builtin_function_start To: Sami Tolvanen Cc: Kees Cook , Catalin Marinas , Mark Rutland , Nathan Chancellor , Nick Desaulniers , Will Deacon , linux-arm-kernel , Linux Kernel Mailing List , llvm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, Apr 2, 2022 at 5:19 AM Sami Tolvanen wrot= e: > > Clang 14 added support for the __builtin_function_start() > built-in function, which allows us to implement function_nocfi() > without architecture-specific inline assembly. This patch changes > CONFIG_CFI_CLANG to depend on the built-in and effectively upgrades > the minimum supported compiler version for CFI to Clang 14. >From this description, I think the straight-forward change would be: depends on CLANG_VERSION >=3D 120000 --> depends on CLANG_VERSION >=3D 140000 Any reason to avoid this? > > Signed-off-by: Sami Tolvanen > --- > arch/Kconfig | 5 +---- > init/Kconfig | 3 +++ > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 29b0167c088b..eecfc2809781 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -723,10 +723,7 @@ config ARCH_SUPPORTS_CFI_CLANG > config CFI_CLANG > bool "Use Clang's Control Flow Integrity (CFI)" > depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG > - # Clang >=3D 12: > - # - https://bugs.llvm.org/show_bug.cgi?id=3D46258 > - # - https://bugs.llvm.org/show_bug.cgi?id=3D47479 > - depends on CLANG_VERSION >=3D 120000 > + depends on CC_HAS_BUILTIN_FUNCTION_START > select KALLSYMS > help > This option enables Clang=E2=80=99s forward-edge Control Flow I= ntegrity > diff --git a/init/Kconfig b/init/Kconfig > index ddcbefe535e9..f024fd353373 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -86,6 +86,9 @@ config CC_HAS_ASM_INLINE > config CC_HAS_NO_PROFILE_FN_ATTR > def_bool $(success,echo '__attribute__((no_profile_instrument_fun= ction)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) > > +config CC_HAS_BUILTIN_FUNCTION_START > + def_bool $(success,echo 'void f(void) {}; void *p =3D __builtin_f= unction_start(f);' | $(CC) -x c - -c -o /dev/null) > + > config PAHOLE_VERSION > int > default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) > -- > 2.35.0 > -- Best Regards Masahiro Yamada 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2C9D0C433EF for ; Sat, 2 Apr 2022 13:33:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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