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=ham 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 5C051C433DF for ; Tue, 13 Oct 2020 23:47:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28C9F21D7F for ; Tue, 13 Oct 2020 23:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602632859; bh=v47zWnOifkArdyDkaoIzDw+kDVLIkz/Iee4au+yhT9s=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=wo9dSSQOS6pcxUKAr1h+r202KW6vks0GMfS79h6qaCiOsyMIbzLCRrEgcGXLEeuPG /KXm1L1bKvO3/GhS+l9VhpaBh+/kzolZe9Gaxr7uS1sJxAa1pFpFvWzPIZN+OR6lR0 7h8qfPN0Llghvqa5ulv8dGOJflSV6ZK0TrsvWgcM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389019AbgJMXri (ORCPT ); Tue, 13 Oct 2020 19:47:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:58732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389017AbgJMXri (ORCPT ); Tue, 13 Oct 2020 19:47:38 -0400 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 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org 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,) _