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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 027DFC43387 for ; Mon, 7 Jan 2019 08:52:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD41A20881 for ; Mon, 7 Jan 2019 08:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726676AbfAGIw5 (ORCPT ); Mon, 7 Jan 2019 03:52:57 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:49181 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726572AbfAGIw5 (ORCPT ); Mon, 7 Jan 2019 03:52:57 -0500 X-IronPort-AV: E=Sophos;i="5.56,450,1539619200"; d="scan'208";a="51461993" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 07 Jan 2019 16:52:53 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id 6C3404B7EC74; Mon, 7 Jan 2019 16:52:50 +0800 (CST) Received: from [10.167.226.60] (10.167.226.60) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 7 Jan 2019 16:52:52 +0800 Subject: Re: [PATCH] x86/boot: drop memset from copy.S To: , , CC: , , References: <20190107074056.12532-1-caoj.fnst@cn.fujitsu.com> <000CE7C8-33F3-404A-9E7D-F2CCB0BA110E@zytor.com> From: Cao jin Message-ID: <28158fd7-8569-e0c1-75d0-c423330e256d@cn.fujitsu.com> Date: Mon, 7 Jan 2019 16:52:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <000CE7C8-33F3-404A-9E7D-F2CCB0BA110E@zytor.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.60] X-yoursite-MailScanner-ID: 6C3404B7EC74.A7781 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: caoj.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 1/7/19 3:59 PM, hpa@zytor.com wrote: > On January 6, 2019 11:40:56 PM PST, Cao jin wrote: >> According to objdump output of setup, function memset is not used in >> setup code. Currently, all usage of memset in setup come from macro >> definition of string.h. >> >> Signed-off-by: Cao jin >> --- >> Compiled and booted under x86_64; compiled under i386. >> >> Questions: now there is 2 definition of memcpy, one lies in copy.S, >> another lies in string.h which is mapped to gcc builtin function. Do we >> still need 2 definition? Could we move the content of copy.S to >> boot/string.c? >> >> At first glance, the usage of string.{c.h} of setup is kind of >> confusing, >> they are also used in compressed/ and purgatory/ >> >> arch/x86/boot/copy.S | 15 --------------- >> 1 file changed, 15 deletions(-) >> >> diff --git a/arch/x86/boot/copy.S b/arch/x86/boot/copy.S >> index 15d9f74b0008..5157d08b0ff2 100644 >> --- a/arch/x86/boot/copy.S >> +++ b/arch/x86/boot/copy.S >> @@ -33,21 +33,6 @@ GLOBAL(memcpy) >> retl >> ENDPROC(memcpy) >> >> -GLOBAL(memset) >> - pushw %di >> - movw %ax, %di >> - movzbl %dl, %eax >> - imull $0x01010101,%eax >> - pushw %cx >> - shrw $2, %cx >> - rep; stosl >> - popw %cx >> - andw $3, %cx >> - rep; stosb >> - popw %di >> - retl >> -ENDPROC(memset) >> - >> GLOBAL(copy_from_fs) >> pushw %ds >> pushw %fs > > This is dependent on both gcc version and flags. > Thanks for your info, but I still don't quite get your point. All files who has memset reference in setup will also #include "string.h", so how gcc version and flags will associate memset reference to the assembly function by force? Hope to get a little more details when you are convenient:)