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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 6EBDEC43387 for ; Fri, 11 Jan 2019 03:40:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D2B02133F for ; Fri, 11 Jan 2019 03:40:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730498AbfAKDkj (ORCPT ); Thu, 10 Jan 2019 22:40:39 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:6470 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726531AbfAKDki (ORCPT ); Thu, 10 Jan 2019 22:40:38 -0500 X-IronPort-AV: E=Sophos;i="5.56,463,1539619200"; d="scan'208";a="51761711" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 11 Jan 2019 11:40:37 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id F15044BAD909; Fri, 11 Jan 2019 11:40:36 +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; Fri, 11 Jan 2019 11:40:35 +0800 Subject: Re: [PATCH] x86/boot: drop memset from copy.S From: Cao jin To: , CC: , , , References: <20190107074056.12532-1-caoj.fnst@cn.fujitsu.com> <4bb8f61a-f93c-4b30-9990-ecf5a8ddc998@cn.fujitsu.com> Message-ID: <1b9db13b-ebe9-70f7-bc79-b608d8906a4b@cn.fujitsu.com> Date: Fri, 11 Jan 2019 11:40:53 +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: <4bb8f61a-f93c-4b30-9990-ecf5a8ddc998@cn.fujitsu.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: F15044BAD909.A7C5A 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 On 1/8/19 4:46 PM, Cao jin wrote: > One more question: in compressed/, for mem*(), it seems we both use the > macros of boot/string.h, and the functions of compressed/string.c. Is > that what we want? > > compressed/ is compiled with -O2, so it cannot be told by objdump -d, > but still can be confirmed by nm <*.o>, for example: > > $nm arch/x86/boot/compressed/eboot.o > U memcpy > U memset > > $nm arch/x86/boot/compressed/pgtable_64.o > # No entry of mem*() > > both of eboot.c and pgtable_64.c #include "../string.h", and use some of > mem*(), it is counter-intuitive to me. Very appreciate it someone can > leave a hint. > Well, I think HPA's previous answer is also suitable for this question, with -O2, sometimes __builtin_mem*() is optimized as inline code, while sometimes just emit a call to corresponding self-defined mem*() functions. -- Sincerely, Cao jin