From patchwork Tue Jan 23 22:59:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 13528251 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BFD114120C; Tue, 23 Jan 2024 23:00:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706050809; cv=none; b=J54IA522C4isH8kSPm0GYWuv1Qom0MNGYpbPM6ZUbp4KT+e0BC80g/QHHOOehAxmaskzSHnoX6Qub8I4vDxdIGCfFvyfawE5Th6a+wnrtotn1cXekdIiKXH3F7ppQ7juBtXN+nrbz1Om2mcHtyrdiG6TZVGUeKuZ0QxfcctWsZg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706050809; c=relaxed/simple; bh=pqpVjk8HX7VL6g1Q9EMOtXMob1urEAYYXk6Z618rEPA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=PEIXlOWOETGhcbka0hnatUv8Wsdqf1FfXxAHgSyvl8RNu048mLdUJ/+gbK3NidnuHvtedtApbcgNTA8DbrNZ9Fotn2D2ixvSjj7roc0wPrEGYkBSFIZ3wQlOvrt6/8+7ibqL0NJ1swqGkJ1zn4Mdr2vb4Ismmn2uJq5LWR+4UDM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jAoxWhCq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jAoxWhCq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82FB9C43394; Tue, 23 Jan 2024 23:00:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706050809; bh=pqpVjk8HX7VL6g1Q9EMOtXMob1urEAYYXk6Z618rEPA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=jAoxWhCqM5qLtmyVk4cFQP+mwISnNe7n35p8T8gpypm9mTTinatigBB7ExR4Leip1 NlBgIXN/o57qF02Nlgzjhc9A4U29nI+WaBA2+106uaUNxOC/3peQfnK0SuPW1l5eQe 2jUZPdMPCWw0cdApKB0gFZfGIq/YDbuM64Kc5HYJqNnmtyaH2GMfZ2ktOk3hps396f KswJ0c1mdynLwJtjI0aVlGgzhhNz2xfijdT96AxkTqrmVP2drGZphoapXsQ6uaigZV CqluqWEP5y8HIwNOTWOVcKSlBaxnhiEljVPYj3UXiJxSxHwZObVdnOhGXKEoC3Zo3V 1mlJJfZ0m3Dqg== From: Nathan Chancellor Date: Tue, 23 Jan 2024 15:59:54 -0700 Subject: [PATCH 1/2] um: Fix adding '-no-pie' for clang Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240123-fix-uml-clang-18-v1-1-efc095519cf9@kernel.org> References: <20240123-fix-uml-clang-18-v1-0-efc095519cf9@kernel.org> In-Reply-To: <20240123-fix-uml-clang-18-v1-0-efc095519cf9@kernel.org> To: richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, masahiroy@kernel.org Cc: nathan@kernel.org, nicolas@fjasle.eu, ndesaulniers@google.com, morbo@google.com, justinstitt@google.com, linux-um@lists.infradead.org, linux-kbuild@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev, stable@vger.kernel.org X-Mailer: b4 0.13-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=2539; i=nathan@kernel.org; h=from:subject:message-id; bh=pqpVjk8HX7VL6g1Q9EMOtXMob1urEAYYXk6Z618rEPA=; b=owGbwMvMwCUmm602sfCA1DTG02pJDKkbXL7XGN+6vvxLxcGMT3k7ljcENiwJYw3IvCTmpN86I aXyyepNHaUsDGJcDLJiiizVj1WPGxrOOct449QkmDmsTCBDGLg4BWAi8vmMDKvCe0V5P8XUOZQW 83F9CenJOti0NvmYwTbR/1OnbHJ9cI+R4e25yU9n6x1e5bO/96HZW+fVgYtuXZ/ZmFjz6vmT3Zd cTzAAAA== X-Developer-Key: i=nathan@kernel.org; a=openpgp; fpr=2437CB76E544CB6AB3D9DFD399739260CB6CB716 The kernel builds with -fno-PIE, so commit 883354afbc10 ("um: link vmlinux with -no-pie") added the compiler linker flag '-no-pie' via cc-option because '-no-pie' was only supported in GCC 6.1.0 and newer. While this works for GCC, this does not work for clang because cc-option uses '-c', which stops the pipeline right before linking, so '-no-pie' is unconsumed and clang warns, causing cc-option to fail just as it would if the option was entirely unsupported: $ clang -Werror -no-pie -c -o /dev/null-x c /dev/null clang-16: error: argument unused during compilation: '-no-pie' [-Werror,-Wunused-command-line-argument] A recent version of clang exposes this because it generates a relocation under '-mcmodel=large' that is not supported in PIE mode: /usr/sbin/ld: init/main.o: relocation R_X86_64_32 against symbol `saved_command_line' can not be used when making a PIE object; recompile with -fPIE /usr/sbin/ld: failed to set dynamic section sizes: bad value clang: error: linker command failed with exit code 1 (use -v to see invocation) Remove the cc-option check altogether. It is wasteful to invoke the compiler to check for '-no-pie' because only one supported compiler version does not support it, GCC 5.x (as it is supported with the minimum version of clang and GCC 6.1.0+). Use a combination of the gcc-min-version macro and CONFIG_CC_IS_CLANG to unconditionally add '-no-pie' with CONFIG_LD_SCRIPT_DYN=y, so that it is enabled with all compilers that support this. Furthermore, using gcc-min-version can help turn this back into LINK-$(CONFIG_LD_SCRIPT_DYN) += -no-pie when the minimum version of GCC is bumped past 6.1.0. Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/1982 Signed-off-by: Nathan Chancellor --- arch/um/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/um/Makefile b/arch/um/Makefile index 82f05f250634..34957dcb88b9 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -115,7 +115,9 @@ archprepare: $(Q)$(MAKE) $(build)=$(HOST_DIR)/um include/generated/user_constants.h LINK-$(CONFIG_LD_SCRIPT_STATIC) += -static -LINK-$(CONFIG_LD_SCRIPT_DYN) += $(call cc-option, -no-pie) +ifdef CONFIG_LD_SCRIPT_DYN +LINK-$(call gcc-min-version, 60100)$(CONFIG_CC_IS_CLANG) += -no-pie +endif LINK-$(CONFIG_LD_SCRIPT_DYN_RPATH) += -Wl,-rpath,/lib CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) \