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=-12.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 112DCC06511 for ; Tue, 2 Jul 2019 08:14:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF347206A2 for ; Tue, 2 Jul 2019 08:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562055298; bh=UHj+reTeQRaOFAHNyvjjTOieOnvPAd53doWoMIt3ixE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=p3v7JGti4rNoN32uwZIuo49LPtwqaoKYfx90fwItl6EvNGZ+i7GJLG6KOlCtxtT9O efBaN4J3nYBpsF44jgYtFxIBH8V15hSsYSxU4IP6KJ6uXi5JtPD2B2NdtW8ALGD6qi L1wXbkominqRgBMjRSmWNV53MFUy9zbXXXL08VOs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727771AbfGBIOx (ORCPT ); Tue, 2 Jul 2019 04:14:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:51968 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727177AbfGBIFo (ORCPT ); Tue, 2 Jul 2019 04:05:44 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2B68321841; Tue, 2 Jul 2019 08:05:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054742; bh=UHj+reTeQRaOFAHNyvjjTOieOnvPAd53doWoMIt3ixE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yxwORs356FDiGVF0JtNDdDj93Dyd3ax/qdbQ2qD+TPkE9VSMk6+PZToydHqGnY0CZ u9kvZa6Ppvr8fQixgYbosvonRhngWBLrt0wCkgWGJ5wrhE2fgtAWWPEfFxDocNu3Nr FAbKu95jJ6+gQc4LG1PlXCpJUH3wedqyVNSESZw8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qian Cai , Dave Martin , Nick Desaulniers , Nathan Chancellor , Will Deacon Subject: [PATCH 4.19 04/72] arm64: Dont unconditionally add -Wno-psabi to KBUILD_CFLAGS Date: Tue, 2 Jul 2019 10:01:05 +0200 Message-Id: <20190702080124.797142876@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.564652899@linuxfoundation.org> References: <20190702080124.564652899@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nathan Chancellor commit fa63da2ab046b885a7f70291aafc4e8ce015429b upstream. This is a GCC only option, which warns about ABI changes within GCC, so unconditionally adding it breaks Clang with tons of: warning: unknown warning option '-Wno-psabi' [-Wunknown-warning-option] and link time failures: ld.lld: error: undefined symbol: __efistub___stack_chk_guard >>> referenced by arm-stub.c:73 (/home/nathan/cbl/linux/drivers/firmware/efi/libstub/arm-stub.c:73) >>> arm-stub.stub.o:(__efistub_install_memreserve_table) in archive ./drivers/firmware/efi/libstub/lib.a These failures come from the lack of -fno-stack-protector, which is added via cc-option in drivers/firmware/efi/libstub/Makefile. When an unknown flag is added to KBUILD_CFLAGS, clang will noisily warn that it is ignoring the option like above, unlike gcc, who will just error. $ echo "int main() { return 0; }" > tmp.c $ clang -Wno-psabi tmp.c; echo $? warning: unknown warning option '-Wno-psabi' [-Wunknown-warning-option] 1 warning generated. 0 $ gcc -Wsometimes-uninitialized tmp.c; echo $? gcc: error: unrecognized command line option ‘-Wsometimes-uninitialized’; did you mean ‘-Wmaybe-uninitialized’? 1 For cc-option to work properly with clang and behave like gcc, -Werror is needed, which was done in commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to cc-option to support clang"). $ clang -Werror -Wno-psabi tmp.c; echo $? error: unknown warning option '-Wno-psabi' [-Werror,-Wunknown-warning-option] 1 As a consequence of this, when an unknown flag is unconditionally added to KBUILD_CFLAGS, it will cause cc-option to always fail and those flags will never get added: $ clang -Werror -Wno-psabi -fno-stack-protector tmp.c; echo $? error: unknown warning option '-Wno-psabi' [-Werror,-Wunknown-warning-option] 1 This can be seen when compiling the whole kernel as some warnings that are normally disabled (see below) show up. The full list of flags missing from drivers/firmware/efi/libstub are the following (gathered from diffing .arm64-stub.o.cmd): -fno-delete-null-pointer-checks -Wno-address-of-packed-member -Wframe-larger-than=2048 -Wno-unused-const-variable -fno-strict-overflow -fno-merge-all-constants -fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types -ffreestanding -fno-stack-protector Use cc-disable-warning so that it gets disabled for GCC and does nothing for Clang. Fixes: ebcc5928c5d9 ("arm64: Silence gcc warnings about arch ABI drift") Link: https://github.com/ClangBuiltLinux/linux/issues/511 Reported-by: Qian Cai Acked-by: Dave Martin Reviewed-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -51,7 +51,7 @@ endif KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -KBUILD_CFLAGS += -Wno-psabi +KBUILD_CFLAGS += $(call cc-disable-warning, psabi) KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) KBUILD_CFLAGS += $(call cc-option,-mabi=lp64)