From owner-freebsd-ia32@FreeBSD.ORG Mon Sep 22 22:29:36 2008 Return-Path: Delivered-To: freebsd-ia32@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AC1CD10657A4 for ; Mon, 22 Sep 2008 22:29:36 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (bigknife-pt.tunnel.tserv9.chi1.ipv6.he.net [IPv6:2001:470:1f10:75::2]) by mx1.freebsd.org (Postfix) with ESMTP id 2F1548FC1A for ; Mon, 22 Sep 2008 22:29:36 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from localhost.corp.yahoo.com (john@localhost [IPv6:::1]) (authenticated bits=0) by server.baldwin.cx (8.14.2/8.14.2) with ESMTP id m8MMTNqB064204; Mon, 22 Sep 2008 18:29:30 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: freebsd-ia32@freebsd.org Date: Mon, 22 Sep 2008 18:06:25 -0400 User-Agent: KMail/1.9.7 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200809221806.25680.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [IPv6:::1]); Mon, 22 Sep 2008 18:29:30 -0400 (EDT) X-Virus-Scanned: ClamAV 0.93.1/8310/Mon Sep 22 14:58:13 2008 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,NO_RELAYS autolearn=ham version=3.1.3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on server.baldwin.cx Cc: Subject: Re: Suspicious physical memory map from BIOS X-BeenThere: freebsd-ia32@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: FreeBSD on the IA-32 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Sep 2008 22:29:36 -0000 On Sunday 21 September 2008 11:08:27 pm questions wrote: > Hi, > > I am sorry if this isn't the correct mailing list to ask my question. > Actually, I posted this on freebsd-questions list but didn't get any reply. > I couldn't find any better mailing list to post this question on. > > I have some problem with physical memory being getting reported incorrectly > on Freebsd 6.3. I have a Xeon series 5300 CPU with 4GB of RAM installed but > BIOS call actually returns following usable physical memory map - > > base address = 0, length = 640K > base address = 1M, length = 2.5G > base address = 4G, length = 5.5G > > How am I getting this third segment? The 2.5g -> 4g window of address space is used for non-memory things like APICs (local APICs and I/O APICs), PCI memio, etc. > Also, in function getmemsize() in machdep.c, why the variable 'Maxmem' is > set to 'Maxmem*4' when hw.physmem and the > highest page number obtained from physical memory map don't match? It's not set to that, it is used for a printf. Maxmem is a count of pages. Each page on i386 holds 4K. The printf wants to print out the number of kilobytes, so it uses 'Maxmem * 4' to convert from number of 4k pages, to number of K. -- John Baldwin