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 81F35ECDE43 for ; Mon, 22 Oct 2018 07:36:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3596120779 for ; Mon, 22 Oct 2018 07:36:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3596120779 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 S1727749AbeJVPyN (ORCPT ); Mon, 22 Oct 2018 11:54:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47032 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727350AbeJVPyN (ORCPT ); Mon, 22 Oct 2018 11:54:13 -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 087C399DB9; Mon, 22 Oct 2018 07:36:53 +0000 (UTC) Received: from localhost (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 366495D73F; Mon, 22 Oct 2018 07:36:49 +0000 (UTC) Date: Mon, 22 Oct 2018 15:36:46 +0800 From: Baoquan He To: Chao Fan Cc: dyoung@redhat.com, "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: <20181022073646.GM1885@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> <20181022060613.GK1885@192.168.1.4> <20181022073050.GB7641@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181022073050.GB7641@localhost.localdomain> 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 [10.5.110.38]); Mon, 22 Oct 2018 07:36:53 +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 03:30pm, Chao Fan wrote: > On Mon, Oct 22, 2018 at 02:06:13PM +0800, Baoquan He wrote: > >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? > > The second parameter of kstrtoull(), the 16 you mentioned means > hexadecimal, not the length. Yes, you are right. > I checked my host and guest, the value are ACPI20=0xbfbfa014, ACPI20=0xdb807000. > The length of memory is 8. Well the max memory address is 16, add > "0x" and '\0' is 19. So I set it as 20. > I am not sure whether 8 is enough for the address, if OK, 11 will > be enough, or 19 is OK. I am fine with 20. Thanks.