From owner-freebsd-arm@freebsd.org Tue Jun 14 16:15:49 2016 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 27BD1B6A5C7 for ; Tue, 14 Jun 2016 16:15:49 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from outbound1a.eu.mailhop.org (outbound1a.eu.mailhop.org [52.58.109.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 8E31C2E10 for ; Tue, 14 Jun 2016 16:15:48 +0000 (UTC) (envelope-from ian@freebsd.org) X-MHO-User: 42ef3389-324b-11e6-ac92-3142cfe117f2 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 73.34.117.227 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [73.34.117.227]) by outbound1.eu.mailhop.org (Halon Mail Gateway) with ESMTPSA; Tue, 14 Jun 2016 16:15:50 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.14.9) with ESMTP id u5EGFfad001402; Tue, 14 Jun 2016 10:15:41 -0600 (MDT) (envelope-from ian@freebsd.org) Message-ID: <1465920941.1188.150.camel@freebsd.org> Subject: Re: A possible solution to booting from another USB stick From: Ian Lepore To: Russell Haley Cc: freebsd-arm , Lou Katz Date: Tue, 14 Jun 2016 10:15:41 -0600 In-Reply-To: References: <20160610071928.GA75585@metron.com> <1465864289.1188.140.camel@freebsd.org> Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.16.5 FreeBSD GNOME Team Port Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Jun 2016 16:15:49 -0000 On Tue, 2016-06-14 at 08:46 -0700, Russell Haley wrote: > On Mon, Jun 13, 2016 at 5:31 PM, Ian Lepore wrote: > > On Fri, 2016-06-10 at 00:19 -0700, Lou Katz wrote: > > > It occurred to me that as long as I had the same version of > > > FreeBSD > > > on the > > > bootable card and in a USB adapter I could boot normally, then > > > mount > > > the system on the adapter card and do a chroot. > > > > > > A quicky and dirty test indicates that might work for what I want > > > to > > > do, > > > which is to: > > > a. modify an application > > > b. add or subtract data files > > > and as a freebie, I seem to get > > > c. ability to change things without rebooting. > > > > > > I will report back after I try this in earnest. > > > > > > Thanks for the feedback. > > > > > > > I apparently missed the first round of this question. > > > > In uboot, you need to do a "usb start", then do "usb dev" and see > > if it > > recognizes your disk device. If so, you're in business, tell ubldr > > to > > load the kernel from it instead of sdcard by doing: > > > > setenv loaderdev disk1 > > > > If there are multiple disks you might need disk2, disk3, whatever. > > If > > there are multiple partitions involved you might need, for example, > > disk1:2 to boot from partition 2. > > So does that mean there are three possible answers? > > 1) Create a new kernel and set ROOTDEVNAME" > > options ROOTDEVNAME=\"ufs:mmcsd0s2\" > The ROOTDEVNAME from kernel config is used as a fallback if no vfs.root.mountfrom is set. It's generally useful only when you bypass ubldr and load the kernel directly from uboot. > > 2) If you have a good image with a kernel and rootfs on USB use a > u-boot environment variable: > > uboot> setenv loaderdev disk1 > This is the way to get the kernel and the root filesystem to come from the same alternate disk device/partition. > > 3) If you can set the loader.conf file and want to run kernel on a > default image (sdcard) and rootfs on USB: > > /boot/loader.conf > > (on the sd-card root) has > > vfs.root.mountfrom="ufs:/dev/ufs/bsd11" If you have this in loader.conf, it will override ubldr's logic that automatically sets it from what it finds in /etc/fstab. You'd get the effect of the kernel coming from sdcard, and the rootfs from another device. -- Ian