From owner-freebsd-acpi@FreeBSD.ORG Fri Jul 12 21:12:02 2013 Return-Path: Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 01F74B0F; Fri, 12 Jul 2013 21:12:02 +0000 (UTC) (envelope-from rathaval@uci.edu) Received: from mda2.es.uci.edu (mda2.es.uci.edu [128.200.80.5]) by mx1.freebsd.org (Postfix) with ESMTP id D3EE91F2E; Fri, 12 Jul 2013 21:12:01 +0000 (UTC) Received: from esmtp1.es.uci.edu (esmtp1.es.uci.edu [128.195.153.131]) by mda2.es.uci.edu (8.13.8/8.13.8) with ESMTP id r6CLB6Tu224366; Fri, 12 Jul 2013 14:11:06 -0700 Received: from mail-wg0-f49.google.com (mail-wg0-f49.google.com [74.125.82.49]) (authenticated bits=0) by esmtp1.es.uci.edu (8.13.8/8.13.8) with ESMTP id r6CLAvHx926285 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT); Fri, 12 Jul 2013 14:10:59 -0700 X-UCInetID: rathaval Received: by mail-wg0-f49.google.com with SMTP id a12so8404024wgh.4 for ; Fri, 12 Jul 2013 14:10:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=GNjlvdAF1lC1jBODs5BOt83TP++iMYREegT8mq7HDUw=; b=fZCtUB0eGMbwwnXJIrQOyDpso/vX9XHIDGOgssv2651kibQcKWpgHdBYWZGlQ1JSCS 7PHWNiGM7LgwM9f59CkEJtKBGVOy0/2g5yLf3FjW8/lWcz/avQhXPGaBIPAHtQ6guye8 9/bQ6oLa+w3a1EwOFHwyp8e0vKxpXo4+I2x4FBoTRsxvuVXmDX80zvacLs2VlRMMG8sP EhvaAKrV/cqQjaEYykUfnsE2kwHdYSOMiJa7ptReMG9S1A8RZqIYxaF49jMcOcNV+CPh tLkse1CEA0jPPX+C87CdlvO1ZU1Tkx9qx8QSSSZgBtdvCOALbvn9G2xNmFfZwgJVQoYv dOuA== X-Received: by 10.180.211.233 with SMTP id nf9mr2690761wic.41.1373663456692; Fri, 12 Jul 2013 14:10:56 -0700 (PDT) MIME-Version: 1.0 Received: by 10.194.9.165 with HTTP; Fri, 12 Jul 2013 14:10:36 -0700 (PDT) In-Reply-To: <201307121650.41701.jhb@freebsd.org> References: <201307121650.41701.jhb@freebsd.org> From: Rohit Athavale Date: Fri, 12 Jul 2013 14:10:36 -0700 Message-ID: Subject: Re: ACPI MADT BSP Details To: John Baldwin Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: freebsd-acpi@freebsd.org X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Jul 2013 21:12:02 -0000 Thanks John. After reading into details of the ACPI spec, it is also said in the spec that the first processor APIC entry also happens to be the BSP . It is expected the BSP always be kept the first entry in processor APIC's. Best Regards, Rohit *A*thavale On Fri, Jul 12, 2013 at 1:50 PM, John Baldwin wrote: > On Wednesday, July 10, 2013 7:48:42 pm Rohit Athavale wrote: > > Hi Folks, > > > > I have two questions about discovering the processors from the MADT > table. > > > > Firstly, > > Can we find out which processor is the BSP from the MADT tables? > > When comparing the userland mptable binary's output versus acpidump's > > output I noticed that mptable informs us about which processor is the BSP > > and which are AP's . > > However I did not see this in the MADT tables. > > Is there a way to find out which processor is the BSP by means of any of > > the ACPI tables. > > Nope. You can read the local APIC ID of the current CPU during your > bootstrap > though. > > > Secondly, > > Can we write into /dev/mem to say update the contents of MPTable with > > values that are non -default. I plan to read some values from the ACPI > > tables and update the MP tables. > > Is the /dev/mem/ file composed of physical addresses for user space > memory > > ? I know this may not qualify as the correct place to ask,but I guess > acpi > > list might have an answer to this. > > Yes, you can likely do this. > > -- > John Baldwin >