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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 D76CBC2B9F4 for ; Sat, 19 Jun 2021 06:23:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC161611CC for ; Sat, 19 Jun 2021 06:23:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231737AbhFSGZ7 (ORCPT ); Sat, 19 Jun 2021 02:25:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229851AbhFSGZ7 (ORCPT ); Sat, 19 Jun 2021 02:25:59 -0400 Received: from mail-oi1-x230.google.com (mail-oi1-x230.google.com [IPv6:2607:f8b0:4864:20::230]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52AF4C061767 for ; Fri, 18 Jun 2021 23:23:47 -0700 (PDT) Received: by mail-oi1-x230.google.com with SMTP id s23so13256687oiw.9 for ; Fri, 18 Jun 2021 23:23:47 -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=g86XYumTkqevhSftkAkowJoLhtGajRxQu1ICRJSfKts=; b=AiAri9rbrByHK1bVXqA5i4n0sG+9/HzQeQlxk47cWkrzB91qDsqgXEWXwqRfR/qmI5 O7J3kWdV9NTf2pj30dkdsnelW1snTjbKgAQbYOLuRWGRvaUWltWVMs1VzHVZPWluXyQi 5aPlTiYluh+hpW27Q00Uhj9j6GhpPOJJLXr1wZhtNkUjEhGReif0cNTC1pNThtEcwjle 3j3oMGbJVF0aUGKMYxSyHbmrO09K91xJfjwbNcMlItXJEM7EC7w04IzHUc37Q81vIPgs lytLMs+QRpzm9Jt+2bt5zhDWoABcGCs6z0Jls9mKdEJPpIc15MiOU0P36iLsuBrdpEOM QKNw== 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=g86XYumTkqevhSftkAkowJoLhtGajRxQu1ICRJSfKts=; b=mDybRnQO2L+rvk53Okw8iNd0+M4R/jTtADrYCZeCtNSk0aX3iZ2ZQWVHfQM85oZe5L eBlZcZpj1p5cwGJxyu0R0jyVdJk3qINkx93AuF0+N55OtPH7kyMOqH+s/tPbDworEIa8 QL/7N7CebZXKVk16I2tpeRmn5lzglcNmwRe2HjYDZ4olW9hnSPbhCp0SNLy0lANTbr8T CgA1skEqb6UOSiqf/2mVS7Py2x7XzI93ZAmYQbYkNfuaq3mFNEvdMcTYxwyldmu+xxYv +ZXORovuHW2pZjF0LecGgGQwtb77wrGarT3PPo4Js9N4Sa2z8uAqWKHw+9yUD0vB5knT S4Ng== X-Gm-Message-State: AOAM5325grSphgfkA8LvyJJkjgq5ZAE2sFnpuX9q8xBt4JJtSbjNs+dJ GFMtYyEDl5J27QwuIKi/3s/DBWeJ+/rOQDxK9DXoJL9V8FruOg== X-Google-Smtp-Source: ABdhPJzFUFNpegpIeES3PrgNs0oQAYXu9Zv+u3+jjIWrBmz2eX3sDR9vbpC4yUPQd/zVVMKtGRueFOAVUjoCXlPod9Y= X-Received: by 2002:aca:ba06:: with SMTP id k6mr9924648oif.70.1624083815429; Fri, 18 Jun 2021 23:23:35 -0700 (PDT) MIME-Version: 1.0 References: <20210618233023.1360185-1-ndesaulniers@google.com> <20210618233023.1360185-3-ndesaulniers@google.com> In-Reply-To: <20210618233023.1360185-3-ndesaulniers@google.com> From: Marco Elver Date: Sat, 19 Jun 2021 08:23:23 +0200 Message-ID: Subject: Re: [PATCH 2/2] Kconfig: CC_HAS_NO_PROFILE_FN_ATTR, depend on for GCOV and PGO To: Nick Desaulniers Cc: Kees Cook , Peter Zijlstra , Bill Wendling , Sami Tolvanen , Peter Oberparleiter , Masahiro Yamada , Miguel Ojeda , Nathan Chancellor , Luc Van Oostenryck , Ard Biesheuvel , Will Deacon , Arnd Bergmann , Andrew Morton , Rasmus Villemoes , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, x86@kernel.org, Borislav Petkov , Martin Liska , Jonathan Corbet , Fangrui Song , linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, Dmitry Vyukov , johannes.berg@intel.com, linux-toolchains@vger.kernel.org, Mark Rutland Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Sat, 19 Jun 2021 at 01:30, Nick Desaulniers wrote: > > We don't want compiler instrumentation to touch noinstr functions, which > are annotated with the no_profile function attribute. Add a Kconfig test > for this and make PGO and GCOV depend on it. > > Cc: Masahiro Yamada > Cc: Peter Oberparleiter > Link: https://lore.kernel.org/lkml/YMTn9yjuemKFLbws@hirez.programming.kicks-ass.net/ > Link: https://lore.kernel.org/lkml/YMcssV%2Fn5IBGv4f0@hirez.programming.kicks-ass.net/ > Suggested-by: Peter Zijlstra > Signed-off-by: Nick Desaulniers > --- > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 3 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/init/Kconfig b/init/Kconfig > index 1ea12c64e4c9..540f862b40c6 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -83,6 +83,9 @@ config TOOLS_SUPPORT_RELR > config CC_HAS_ASM_INLINE > def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) > > +config CC_HAS_NO_PROFILE_FN_ATTR > + def_bool $(success,echo '__attribute__((no_profile)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) > + > config CONSTRUCTORS > bool > > diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig > index 58f87a3092f3..19facd4289cd 100644 > --- a/kernel/gcov/Kconfig > +++ b/kernel/gcov/Kconfig > @@ -5,6 +5,7 @@ config GCOV_KERNEL > bool "Enable gcov-based kernel profiling" > depends on DEBUG_FS > depends on !CC_IS_CLANG || CLANG_VERSION >= 110000 > + depends on !X86 || (X86 && CC_HAS_NO_PROFILE_FN_ATTR) [+Cc Mark] arm64 is also starting to rely on noinstr working properly. This should probably be a 'select ARCH_HAS_GCOV_PROFILE_ALL if CC_HAS_NO_PROFILE_FN_ATTR' in the relevant arch/../Kconfig. Alternatively, using: https://lkml.kernel.org/r/YMcssV/n5IBGv4f0@hirez.programming.kicks-ass.net But I'd probably not overcomplicate things at this point and just use ARCH_HAS_GCOV_PROFILE_ALL, because GCOV seems to be a) rarely used, and b) if someone decides to selectively instrument stuff like entry code, we can just say it's user error. > select CONSTRUCTORS > default n > help > diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig > index d2053df1111c..26f75ac4c6c1 100644 > --- a/kernel/pgo/Kconfig > +++ b/kernel/pgo/Kconfig > @@ -8,7 +8,8 @@ config PGO_CLANG > bool "Enable clang's PGO-based kernel profiling" > depends on DEBUG_FS > depends on ARCH_SUPPORTS_PGO_CLANG > - depends on CC_IS_CLANG && CLANG_VERSION >= 120000 > + depends on CC_IS_CLANG > + depends on CC_HAS_NO_PROFILE_FN_ATTR > help > This option enables clang's PGO (Profile Guided Optimization) based > code profiling to better optimize the kernel. > -- > 2.32.0.288.g62a8d224e6-goog >