From patchwork Tue Apr 28 22:14:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 11515741 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BD9A092C for ; Tue, 28 Apr 2020 22:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A21F220731 for ; Tue, 28 Apr 2020 22:14:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Iti+Hequ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726955AbgD1WOv (ORCPT ); Tue, 28 Apr 2020 18:14:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726884AbgD1WOr (ORCPT ); Tue, 28 Apr 2020 18:14:47 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEA90C03C1AC; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id 72so35653389otu.1; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=D5XPjNeCefGZdrfYepQszWv1EoAyH1SJYjMY9egLiRQ=; b=Iti+HequGOL2PRuJbXnmbHCjiKuiBfJAzPaw8pDrLBFUO76wVbANTBmENBrQptVY+X FBumW6Q8M+cJTNNXqkgRIn/BpEW8C4gKFGoOESrw47zC2a6WrAzQH6qGn9YY1yOhQ67K EMVmi6vrNlI4Ug3rb/6YM1mmA9JQwUBotIlqKLfQAl7rKtBO/H7s0FurgDgDdqR/7Pdn byjVkaxjygBHj5EPMqqJRwqwdiN5qa4UJeWxCq8HnLKu8gG7oYy4IU2lUpV4fGn+fM18 vozwJ5GyPiHVyoBoWclyp9cS6to49xOt0mHwaou1wH+RgEcXp37H+5yOM3sNf7jGCsbP 3fAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=D5XPjNeCefGZdrfYepQszWv1EoAyH1SJYjMY9egLiRQ=; b=clg0EzYuGYbeXL+48/jJkgshIL46NOiQMJ1wyYZ5aTMul3ihPuG1CebRh7/ZioU1zG f3UNaFyZH81J/dDuezwmtfvV8WLfUIf9yxmdy+ciSBGGEOyzGbdYyFn4F3WKuEBn74G4 wMe3LXHabmgHb6mXC49tCIc1r5R6OCKF53tcvUC59Yi2lMOzys+L7/dpUo/QRUSsL4TL lrE/UQO9u34rvnMErwpg/ISPIz02vCnXE41LY0niB9DKvTQEA+QDH61JGWYgLMGweug7 mMtFNOcXWwUXubnRqhq8vOALChZsLsTzQF/tRm+c+6y301wTvQNPHXB26v7K4wFrvZxh NVdQ== X-Gm-Message-State: AGi0Pub2QSjtOkZpvil/SgvRSCVBYvPxjWXYJ/opwtXIlZn8QSKoOYxG tQT4hJXfZ3ZSCdy6Yxh1tEM= X-Google-Smtp-Source: APiQypJKBJEUubwCVk6BCR1txO0tCzVgiFwxHfcCK5o8MX1rilWMul+BWNV6kI1sscPSPp8xdpLWng== X-Received: by 2002:a05:6830:1ac6:: with SMTP id r6mr1353744otc.311.1588112085030; Tue, 28 Apr 2020 15:14:45 -0700 (PDT) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 186sm5267476ooi.30.2020.04.28.15.14.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 15:14:44 -0700 (PDT) From: Nathan Chancellor To: Thomas Bogendoerfer , Masahiro Yamada Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, Nick Desaulniers , Fangrui Song , Sami Tolvanen , Dmitry Golovin , Sedat Dilek , Nathan Chancellor Subject: [PATCH v4 3/5] MIPS: Unconditionally specify '-EB' or '-EL' Date: Tue, 28 Apr 2020 15:14:17 -0700 Message-Id: <20200428221419.2530697-4-natechancellor@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428221419.2530697-1-natechancellor@gmail.com> References: <20200423171807.29713-1-natechancellor@gmail.com> <20200428221419.2530697-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org This was all done to work around a GCC bug that has been fixed after 4.2. The kernel requires GCC 4.6 or newer so remove all of these hacks and just use the traditional flags. $ mips64-linux-gcc --version | head -n1 mips64-linux-gcc (GCC) 4.6.3 $ mips64-linux-gcc -EB -dM -E -C -x c /dev/null | grep MIPSE #define MIPSEB 1 #define __MIPSEB__ 1 #define _MIPSEB 1 #define __MIPSEB 1 $ mips64-linux-gcc -EL -dM -E -C -x c /dev/null | grep MIPSE #define __MIPSEL__ 1 #define MIPSEL 1 #define _MIPSEL 1 #define __MIPSEL 1 This is necessary when converting the MIPS VDSO to use $(LD) instead of $(CC) to link because the OUTPUT_FORMAT is defaulted to little endian and only flips to big endian when '-EB' is set on the command line. There is no issue currently because the compiler explicitly passes '-EB' or '-EL' to the linker regardless of whether or not it was provided by the user. Passing '-v' to VDSO_LDFLAGS shows: /libexec/gcc/mips64-linux/9.3.0/collect2 ... -EB ... even though '-EB' is nowhere to be found in KBUILD_CFLAGS. The VDSO Makefile already supports getting '-EB' or '-EL' from KBUILD_CFLAGS through a filter directive but '-EB' or '-EL' is not always present. If we do not do this, we will see the following error when compiling for big endian: $ make -j$(nproc) ARCH=mips CROSS_COMPILE=mips64-linux- \ 64r2el_defconfig arch/mips/vdso/ ... mips64-linux-ld: arch/mips/vdso/elf.o: compiled for a big endian system and target is little endian mips64-linux-ld: arch/mips/vdso/elf.o: endianness incompatible with that of the selected emulation mips64-linux-ld: failed to merge target specific data of file arch/mips/vdso/elf.o ... Remove this legacy hack and just use '-EB' and '-EL' unconditionally. Reported-by: Thomas Bogendoerfer Signed-off-by: Nathan Chancellor --- v3 -> v4: * New patch. arch/mips/Makefile | 25 ------------------------- 1 file changed, 25 deletions(-) diff --git a/arch/mips/Makefile b/arch/mips/Makefile index e1c44aed81565..301efb90b51ed 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -116,33 +116,8 @@ endif cflags-y += -ffreestanding -# -# We explicitly add the endianness specifier if needed, this allows -# to compile kernels with a toolchain for the other endianness. We -# carefully avoid to add it redundantly because gcc 3.3/3.4 complains -# when fed the toolchain default! -# -# Certain gcc versions up to gcc 4.1.1 (probably 4.2-subversion as of -# 2006-10-10 don't properly change the predefined symbols if -EB / -EL -# are used, so we kludge that here. A bug has been filed at -# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29413. -# -# clang doesn't suffer from these issues and our checks against -dumpmachine -# don't work so well when cross compiling, since without providing --target -# clang's output will be based upon the build machine. So for clang we simply -# unconditionally specify -EB or -EL as appropriate. -# -ifdef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_BIG_ENDIAN) += -EB cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -EL -else -undef-all += -UMIPSEB -U_MIPSEB -U__MIPSEB -U__MIPSEB__ -undef-all += -UMIPSEL -U_MIPSEL -U__MIPSEL -U__MIPSEL__ -predef-be += -DMIPSEB -D_MIPSEB -D__MIPSEB -D__MIPSEB__ -predef-le += -DMIPSEL -D_MIPSEL -D__MIPSEL -D__MIPSEL__ -cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' && echo -EB $(undef-all) $(predef-be)) -cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' || echo -EL $(undef-all) $(predef-le)) -endif cflags-$(CONFIG_SB1XXX_CORELIS) += $(call cc-option,-mno-sched-prolog) \ -fno-omit-frame-pointer