From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (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 BBF3372 for ; Tue, 24 Aug 2021 02:27:29 +0000 (UTC) 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> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Transfer-Encoding: 8bit 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 --- 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) -- 2.33.0