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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B0D81ECDE43 for ; Mon, 22 Oct 2018 06:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7380020779 for ; Mon, 22 Oct 2018 06:06:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7380020779 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727650AbeJVOXY (ORCPT ); Mon, 22 Oct 2018 10:23:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57688 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727322AbeJVOXY (ORCPT ); Mon, 22 Oct 2018 10:23:24 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2E868307D846; Mon, 22 Oct 2018 06:06:20 +0000 (UTC) Received: from localhost (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E24F5D73F; Mon, 22 Oct 2018 06:06:16 +0000 (UTC) Date: Mon, 22 Oct 2018 14:06:13 +0800 From: Baoquan He To: "Fan, Chao" , dyoung@redhat.com Cc: "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "linux-efi@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "bp@alien8.de" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "keescook@chromium.org" , "msys.mizuma@gmail.com" , "Indoh, Takao" , "Cao, Jin" Subject: Re: [PATCH v9 5/8] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec Message-ID: <20181022060613.GK1885@192.168.1.4> References: <20181017102012.872-1-fanc.fnst@cn.fujitsu.com> <20181017102012.872-6-fanc.fnst@cn.fujitsu.com> <20181021022650.GI1885@192.168.1.4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 22 Oct 2018 06:06:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/18 at 05:30am, Fan, Chao wrote: > >> +static void get_acpi_rsdp(acpi_physical_address *rsdp_addr) > >> +{ > >> +#ifdef CONFIG_KEXEC > >> + unsigned long long res; > >> + int len = 0; > >> + char *val; > >> + > >> + val = malloc(20); > > > >Why is the length 20? Defined a macro? > > > > Not a calculation, if it's enough to store the address, that will be OK. Sorry, I didn't catch. It's 16 in setup_acpi_rsdp() of drivers/acpi/osl.c . What does 'that' mean? Wondering why not making it 200, it's also enough to store the address.