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=-11.8 required=3.0 tests=BAYES_00,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 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 BD31AC433DF for ; Tue, 13 Oct 2020 23:47:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3C56D21D7F for ; Tue, 13 Oct 2020 23:47:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="eHSI7R7Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C56D21D7F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C7F286B0068; Tue, 13 Oct 2020 19:47:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C2CE16B006E; Tue, 13 Oct 2020 19:47:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ACE236B0070; Tue, 13 Oct 2020 19:47:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0221.hostedemail.com [216.40.44.221]) by kanga.kvack.org (Postfix) with ESMTP id 77A106B0068 for ; Tue, 13 Oct 2020 19:47:40 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0385E180AD807 for ; Tue, 13 Oct 2020 23:47:40 +0000 (UTC) X-FDA: 77368541880.17.care16_3d0f9e027207 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id DF43E180D0184 for ; Tue, 13 Oct 2020 23:47:39 +0000 (UTC) X-HE-Tag: care16_3d0f9e027207 X-Filterd-Recvd-Size: 3852 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 23:47:38 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 87A3021D81; Tue, 13 Oct 2020 23:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602632858; bh=v47zWnOifkArdyDkaoIzDw+kDVLIkz/Iee4au+yhT9s=; h=Date:From:To:Subject:In-Reply-To:From; b=eHSI7R7Z4rUWlVr9ZJH+DnHwxCupaf3aNDe2CZhJ9J/9cB5xsqXNDDIdBXf6Szu0j kxq4607KyaefWCCzqRCHzvVeXEekMRKjZdo129xuALnYtuSH4wwcKTWtgeX5m2ARjB qh22e+qhQMYOgJlElhcWp2sbcuBHDZNSzFnhQ/8c= Date: Tue, 13 Oct 2020 16:47:37 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, ast@kernel.org, daniel@iogearbox.net, elver@google.com, keescook@chromium.org, linux-mm@kvack.org, masahiroy@kernel.org, maskray@google.com, miguel.ojeda.sandonis@gmail.com, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, sedat.dilek@gmail.com, torvalds@linux-foundation.org, vincenzo.frascino@arm.com, will@kernel.org Subject: [patch 002/181] Revert "kbuild: disable clang's default use of -fmerge-all-constants" Message-ID: <20201013234737.IguEuP9Se%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Nick Desaulniers Subject: Revert "kbuild: disable clang's default use of -fmerge-all-constants" This reverts commit 87e0d4f0f37fb0c8c4aeeac46fff5e957738df79. -fno-merge-all-constants has been the default since clang-6; the minimum supported version of clang in the kernel is clang-10 (10.0.1). Link: https://lkml.kernel.org/r/20200902225911.209899-3-ndesaulniers@google.com Link: https://reviews.llvm.org/rL329300. Link: https://github.com/ClangBuiltLinux/linux/issues/9 Signed-off-by: Nick Desaulniers Suggested-by: Nathan Chancellor Tested-by: Sedat Dilek Reviewed-by: Fangrui Song Reviewed-by: Nathan Chancellor Reviewed-by: Sedat Dilek Reviewed-by: Kees Cook Cc: Andrey Konovalov Cc: Marco Elver Cc: Miguel Ojeda Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Masahiro Yamada Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton --- Makefile | 9 --------- 1 file changed, 9 deletions(-) --- a/Makefile~revert-kbuild-disable-clangs-default-use-of-fmerge-all-constants +++ a/Makefile @@ -921,15 +921,6 @@ KBUILD_CFLAGS += $(call cc-disable-warni # disable invalid "can't wrap" optimizations for signed / pointers KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) -# clang sets -fmerge-all-constants by default as optimization, but this -# is non-conforming behavior for C and in fact breaks the kernel, so we -# need to disable it here generally. -KBUILD_CFLAGS += $(call cc-option,-fno-merge-all-constants) - -# for gcc -fno-merge-all-constants disables everything, but it is fine -# to have actual conforming behavior enabled. -KBUILD_CFLAGS += $(call cc-option,-fmerge-constants) - # Make sure -fstack-check isn't enabled (like gentoo apparently did) KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,) _