From patchwork Tue Aug 24 02:26:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 12453827 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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 C88B6C432BE for ; Tue, 24 Aug 2021 02:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACF0D61406 for ; Tue, 24 Aug 2021 02:27:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233657AbhHXC2T (ORCPT ); Mon, 23 Aug 2021 22:28:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:36948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232147AbhHXC2S (ORCPT ); Mon, 23 Aug 2021 22:28:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2B58F6101C; Tue, 24 Aug 2021 02:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629772049; bh=aJDo0HVHGoQr0fB3L9Ko8UYHdW/Y7I5d2sHOlNYTD7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uXps/PBHE4jMq8jSFhDw/ROwedp7lnbAkneniMWv9TRWiie4rJPjUdwpkNV2JT79l oUbOboMUbaqd/fth2dvV6jWYAJ9WRFA79loTXG6kAjFxNuJkTKd2RA9O1/iEN7OAnK utAvXGZ+jzyWNZCqseT8+A7Up6cAfNN984liuU3GDDkjQLgZsOW9PQpgQ4fG8Ptjrr ptwJyEjgRiGwGaOH56WKPMvgR8fFl+V8HUdb2CVLR2Fx5IYMlfWdUydg+KFdvudaR0 HrW531bl76/DeSmmIqAyWZM1NJc+7Q7uD9xAZ7W6/lsQ2oD0nJ99wzf9PSajPa+jW6 ACnL+np9S8uXw== From: Nathan Chancellor To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Masahiro Yamada Cc: "H. Peter Anvin" , Nick Desaulniers , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, llvm@lists.linux.dev, Nathan Chancellor , kernel test robot Subject: [PATCH 1/2] x86: Do not add -falign flags unconditionally for clang Date: Mon, 23 Aug 2021 19:26:39 -0700 Message-Id: <20210824022640.2170859-2-nathan@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210824022640.2170859-1-nathan@kernel.org> References: <20210824022640.2170859-1-nathan@kernel.org> MIME-Version: 1.0 X-Patchwork-Bot: notify Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org 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/ Reported-by: kernel test robot Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Acked-by: Borislav Petkov --- 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 cd3056759880..e8c65f990afd 100644 --- a/arch/x86/Makefile_32.cpu +++ b/arch/x86/Makefile_32.cpu @@ -10,6 +10,12 @@ else tune = $(call cc-option,-mcpu=$(1),$(2)) endif +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 @@ -25,11 +31,11 @@ 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) From patchwork Tue Aug 24 02:26:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 12453825 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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 4C29AC4320A for ; Tue, 24 Aug 2021 02:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F134613D2 for ; Tue, 24 Aug 2021 02:27:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233602AbhHXC2T (ORCPT ); Mon, 23 Aug 2021 22:28:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:37032 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233477AbhHXC2S (ORCPT ); Mon, 23 Aug 2021 22:28:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EBDEF613D5; Tue, 24 Aug 2021 02:27:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629772053; bh=NOvJGCvW1HVdaDqhCUnwbbyYfhSHjlfgYPzYKkOiPeI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sVo8kH14HV4YMJUOa/sFGqFKMlYvaRHWnjrvEpgstLxyWfoE1UaForX7zQQFkmpBb Geep8/Zqy1BvWYK0RIAGXu6dEpxEz/49ho/U/ehCqyXPkV6wZ0P4DPwe56qFFYhfkQ aYsarl6rdNXIFELz7+lEKIKNA21PmggLbrFWwmJmPVabnpAtAIlY7OSPmDfZCUb8zV chWdq/uS+UWzJ6Etm0OD8q7/0gzafwogKdqUygQ48muscUfP9iCwxaUwjwVvqH5nOf 7o2M2apdEIejOD0GG69EhgZOchV9AKwNyIzaze5VLDP4UmF1TlrxWdIDnN4UQgb/y8 aR7u/vij+whEg== From: Nathan Chancellor To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Masahiro Yamada Cc: "H. Peter Anvin" , Nick Desaulniers , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, llvm@lists.linux.dev, Nathan Chancellor Subject: [PATCH 2/2] kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGS Date: Mon, 23 Aug 2021 19:26:40 -0700 Message-Id: <20210824022640.2170859-3-nathan@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210824022640.2170859-1-nathan@kernel.org> References: <20210824022640.2170859-1-nathan@kernel.org> MIME-Version: 1.0 X-Patchwork-Bot: notify Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Similar to commit 589834b3a009 ("kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS"). Clang ignores certain GCC flags that it has not implemented, only emitting a warning: $ echo | clang -fsyntax-only -falign-jumps -x c - clang-14: warning: optimization flag '-falign-jumps' is not supported [-Wignored-optimization-argument] When one of these flags gets added to KBUILD_CFLAGS unconditionally, all subsequent cc-{disable-warning,option} calls fail because -Werror was added to these invocations to turn the above warning and the equivalent -W flag warning into errors. To catch the presence of these flags earlier, turn -Wignored-optimization-argument into an error so that the flags can either be implemented or ignored via cc-option and there are no more weird errors. Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers --- scripts/Makefile.clang | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 4cce8fd0779c..2fe38a9fdc11 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -29,7 +29,11 @@ CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) else CLANG_FLAGS += -fintegrated-as endif +# By default, clang only warns on unknown warning or optimization flags +# Make it behave more like gcc by erroring when these flags are encountered +# so they can be implemented or wrapped in cc-option. CLANG_FLAGS += -Werror=unknown-warning-option +CLANG_FLAGS += -Werror=ignored-optimization-argument KBUILD_CFLAGS += $(CLANG_FLAGS) KBUILD_AFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS