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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A85D7C48BE5 for ; Mon, 21 Jun 2021 23:45:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85E0161289 for ; Mon, 21 Jun 2021 23:45:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231937AbhFUXsI (ORCPT ); Mon, 21 Jun 2021 19:48:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:41562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231569AbhFUXsI (ORCPT ); Mon, 21 Jun 2021 19:48:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 25BEA60FE9; Mon, 21 Jun 2021 23:45:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624319153; bh=diaiwAvN8QgNQIX3GIs2NJUIKQAsbDwsiFGinAjrQ34=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=V8BryDAVDTIMQPVGpUUTubRgwnW5TfmAmKm3zBdQE9xtGWlmtoj8t13tnrxDfXa6Z 8jroe7JygyrNu37Xk8xoL+EKymmY5AT82BlAbjgQgBXhQLriY3B6Izjg8MTtWdSu0t xp6+pnROcXocKlZ4iPuR5E4jbn0YW3Eyd7E9xLf0gIR1QZ5R7JZ9RBkSGdU2gJR2uq mi0qkzj1dXm/YQwg01ayz8v3Q0H8NM1MBFFykmQOu0cZDOISFo4RWoYXScg4uKY/2D 4FKdQQqyvQXUysv1iGlKffT83j7FZeMpla13bkNphZzVzCE+IadL6vPjDhDooiU96/ W0sKl8M2qY3ig== Subject: Re: [PATCH v2 3/3] Kconfig: add ARCH_WANTS_NO_INSTR+CC_HAS_NO_PROFILE_FN_ATTR, depend on for GCOV and PGO To: Nick Desaulniers , Kees Cook Cc: Peter Zijlstra , Bill Wendling , Sami Tolvanen , Peter Oberparleiter , Masahiro Yamada , Miguel Ojeda , 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 , Marco Elver , 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, Heiko Carstens , Vasily Gorbik , Christian Borntraeger , linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas References: <20210621231822.2848305-1-ndesaulniers@google.com> <20210621231822.2848305-4-ndesaulniers@google.com> From: Nathan Chancellor Message-ID: Date: Mon, 21 Jun 2021 16:45:50 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210621231822.2848305-4-ndesaulniers@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On 6/21/2021 4:18 PM, 'Nick Desaulniers' via Clang Built Linux wrote: > We don't want compiler instrumentation to touch noinstr functions, which > are annotated with the no_profile_instrument_function function > attribute. Add a Kconfig test for this and make PGO and GCOV depend on > it. > > If an architecture is using noinstr, it should denote that via this > Kconfig value. That makes Kconfigs that depend on noinstr able to > express dependencies in an architecturally agnostic way. > > 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: Nathan Chancellor > Suggested-by: Peter Zijlstra > Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Small nit below. > --- > Changes V1 -> V2: > * Add ARCH_WANTS_NO_INSTR > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > rather than list architectures explicitly, as per Nathan. > * s/no_profile/no_profile_instrument_function/ > > arch/Kconfig | 7 +++++++ > arch/arm64/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/x86/Kconfig | 1 + > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 7 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 2b4109b0edee..2113c6b3b801 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -285,6 +285,13 @@ config ARCH_THREAD_STACK_ALLOCATOR > config ARCH_WANTS_DYNAMIC_TASK_STRUCT > bool > > +config ARCH_WANTS_NO_INSTR > + bool > + help > + An architecure should select this if the noinstr macro is being used on Architecture > + functions to denote that the toolchain should avoid instrumenting such > + functions and is required for correctness. > + > config ARCH_32BIT_OFF_T > bool > depends on !64BIT > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 9f1d8566bbf9..39bf982b06f8 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -93,6 +93,7 @@ config ARM64 > select ARCH_WANT_FRAME_POINTERS > select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) > select ARCH_WANT_LD_ORPHAN_WARN > + select ARCH_WANTS_NO_INSTR > select ARCH_HAS_UBSAN_SANITIZE_ALL > select ARM_AMBA > select ARM_ARCH_TIMER > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index b4c7c34069f8..bd60310f33b9 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -117,6 +117,7 @@ config S390 > select ARCH_USE_BUILTIN_BSWAP > select ARCH_USE_CMPXCHG_LOCKREF > select ARCH_WANTS_DYNAMIC_TASK_STRUCT > + select ARCH_WANTS_NO_INSTR > select ARCH_WANT_DEFAULT_BPF_JIT > select ARCH_WANT_IPC_PARSE_VERSION > select BUILDTIME_TABLE_SORT > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index da43fd046149..7d6a44bb9b0e 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -114,6 +114,7 @@ config X86 > select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 > select ARCH_WANTS_DYNAMIC_TASK_STRUCT > + select ARCH_WANTS_NO_INSTR > select ARCH_WANT_HUGE_PMD_SHARE > select ARCH_WANT_LD_ORPHAN_WARN > select ARCH_WANTS_THP_SWAP if X86_64 > diff --git a/init/Kconfig b/init/Kconfig > index 1ea12c64e4c9..31397a7a45fb 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_instrument_function)) 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..053447183ac5 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 !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > select CONSTRUCTORS > default n > help > diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig > index d2053df1111c..ce7fe04f303d 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 !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > help > This option enables clang's PGO (Profile Guided Optimization) based > code profiling to better optimize the kernel. >