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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 3E979C43381 for ; Fri, 22 Mar 2019 12:06:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 057E8206C0 for ; Fri, 22 Mar 2019 12:06:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256371; bh=EcaoYsmo0Lk9K3Kx6Xmj/CqTyIb+OlgpxwXJABRVifw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zn7KkH4X4E51EhQ512WCOSiz/jD03DnxIaMy0lLc+36gnvPBr4eakiy73EdM0os5/ X9c5+q1ZNMCHGeHePt0Um4CMsrVUCHNbvw9Heo8e5Odk9PIpFtlmk7koqkSl8vo/sD ji150FEp9D3rgT38KhaqY4I4H6HdsyvhvoI1zFuE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388894AbfCVMGK (ORCPT ); Fri, 22 Mar 2019 08:06:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:44554 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388096AbfCVMGF (ORCPT ); Fri, 22 Mar 2019 08:06:05 -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 95803206C0; Fri, 22 Mar 2019 12:06:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256365; bh=EcaoYsmo0Lk9K3Kx6Xmj/CqTyIb+OlgpxwXJABRVifw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F36xHZXJFmOQos1DE84lSatMilwD4Ig/01E+tam3T5eC3bFEnpvkc8MAG2qMUISne EGpf00HmZUv/WMyTYA/wbDj0rBIyW2DKRGsGc0DYMS+Ap2ti39E26+ksUjjvi/Pn5Q cxYHxhODMemwLiBFRZttjO3cCT0QTDc2ySCosSVk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Finn Thain , Geert Uytterhoeven Subject: [PATCH 4.19 167/280] m68k: Add -ffreestanding to CFLAGS Date: Fri, 22 Mar 2019 12:15:20 +0100 Message-Id: <20190322111323.730143530@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111306.356185024@linuxfoundation.org> References: <20190322111306.356185024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Finn Thain commit 28713169d879b67be2ef2f84dcf54905de238294 upstream. This patch fixes a build failure when using GCC 8.1: /usr/bin/ld: block/partitions/ldm.o: in function `ldm_parse_tocblock': block/partitions/ldm.c:153: undefined reference to `strcmp' This is caused by a new optimization which effectively replaces a strncmp() call with a strcmp() call. This affects a number of strncmp() call sites in the kernel. The entire class of optimizations is avoided with -fno-builtin, which gets enabled by -ffreestanding. This may avoid possible future build failures in case new optimizations appear in future compilers. I haven't done any performance measurements with this patch but I did count the function calls in a defconfig build. For example, there are now 23 more sprintf() calls and 39 fewer strcpy() calls. The effect on the other libc functions is smaller. If this harms performance we can tackle that regression by optimizing the call sites, ideally using semantic patches. That way, clang and ICC builds might benfit too. Cc: stable@vger.kernel.org Reference: https://marc.info/?l=linux-m68k&m=154514816222244&w=2 Signed-off-by: Finn Thain Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman --- arch/m68k/Makefile | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/m68k/Makefile +++ b/arch/m68k/Makefile @@ -58,7 +58,10 @@ cpuflags-$(CONFIG_M5206e) := $(call cc-o cpuflags-$(CONFIG_M5206) := $(call cc-option,-mcpu=5206,-m5200) KBUILD_AFLAGS += $(cpuflags-y) -KBUILD_CFLAGS += $(cpuflags-y) -pipe +KBUILD_CFLAGS += $(cpuflags-y) + +KBUILD_CFLAGS += -pipe -ffreestanding + ifdef CONFIG_MMU # without -fno-strength-reduce the 53c7xx.c driver fails ;-( KBUILD_CFLAGS += -fno-strength-reduce -ffixed-a2