From nobody Tue Dec 19 15:28:47 2023 X-Original-To: freebsd-arm@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4SvgbY0FhWz54QLV for ; Tue, 19 Dec 2023 15:29:29 +0000 (UTC) (envelope-from marietto2008@gmail.com) Received: from mail-ej1-x62d.google.com (mail-ej1-x62d.google.com [IPv6:2a00:1450:4864:20::62d]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4SvgbW4l6Vz4ZdQ for ; Tue, 19 Dec 2023 15:29:27 +0000 (UTC) (envelope-from marietto2008@gmail.com) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20230601 header.b=TXZi4UCo; spf=pass (mx1.freebsd.org: domain of marietto2008@gmail.com designates 2a00:1450:4864:20::62d as permitted sender) smtp.mailfrom=marietto2008@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-ej1-x62d.google.com with SMTP id a640c23a62f3a-a2370535060so263615566b.1 for ; Tue, 19 Dec 2023 07:29:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702999765; x=1703604565; darn=freebsd.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=uZTibxYoVXyZHPrL/nU7tAAF4GnSbtnveYq8sdS6ZzI=; b=TXZi4UCo+ECR251BsWbyxb2lF8hyT7y589uz3akQ986mOW4QR+7rTjod4DarEQ/GmX wfU6P+2U/b1qdKfGF1tCYFzLcNbYyXUOhUJiwP2LKIc07OU3vrtXPkqrpZzlM+74aPCW 9fblFGl/hlBVS8XVBWWp6HoLpZawAALTPDj4L1tkbRbOIikdEnbFf0lpWzoq7Lb3cANX 2UFAjqes1GIAKZER73gy9nirtuFgI0wF+U8x/ZXi+A2aMbqLpxaCMK9ZXX4RwrTfCVVZ Ip32Wej5wWucjBJ/dtp2AluRAY1XHBo6XQstSoSddQi3rYtiecvA3YZ0VrPRjTzT5PRX P07g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702999765; x=1703604565; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=uZTibxYoVXyZHPrL/nU7tAAF4GnSbtnveYq8sdS6ZzI=; b=h3C9TzzAnEJzStznWSTcxI+tbcHtbMmjW9fu5Unr6Mp/sQ8m3EiLftco+7QrTnXgtD MC9T+l8fB55V7xg9Stdh0Nl61dz8EDET0K+kfnCUkMOGUiUzKa8OYHivR/CmRhVX+Z8P GZoVJFfIUA3SYpXJTSqS8RDlniQoSuBXI9IXgKC++36hAdOE9laf4Z9oFAhGWElgGKf5 BXnfvDF8rq1bEHC9Bg9rVhGFdtXuW0G4SYvugBxrkJUdtWr5LjxOgMiijzy+xP3f7jXZ xRSgYrYj7CmrvX0X6KaAaPPXh6z0CCX0zndTglovSxofFOMhANBup9omdSKLAMnLMz/P JCZw== X-Gm-Message-State: AOJu0Yzsm5J6eY8tUbTxw2Pvu0fBIWRaLWO3rL3oey5Pk14C+Y4G8feH aGW1vY7hOzLqie0f7QsNc5wnwHKMRSI7oXlDHrPeapl1TOA= X-Google-Smtp-Source: AGHT+IFsayR6t7I2kBDKEW3prJWkRaTwdXpt7p3hrYKQDThl3p7klUCGTQg2aScpzGktRLrCk8yNKVi4Q4QnSDuSC44= X-Received: by 2002:a17:906:f9c4:b0:a23:49ec:9bad with SMTP id lj4-20020a170906f9c400b00a2349ec9badmr1132099ejb.77.1702999764638; Tue, 19 Dec 2023 07:29:24 -0800 (PST) List-Id: Porting FreeBSD to ARM processors List-Archive: https://lists.freebsd.org/archives/freebsd-arm List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arm@freebsd.org MIME-Version: 1.0 References: <97aa980b9b44.6eb7f9d5c54e7@mailgate.us> In-Reply-To: From: Mario Marietto Date: Tue, 19 Dec 2023 16:28:47 +0100 Message-ID: Subject: Re: How to boot FreeBSD for arm 32 bit as DomU with u-boot on my ARM Chromebook To: Stanislav Silnicki Cc: freebsd-arm@freebsd.org Content-Type: multipart/alternative; boundary="000000000000062155060cde8899" X-Spamd-Result: default: False [-3.00 / 15.00]; URI_COUNT_ODD(1.00)[69]; NEURAL_HAM_SHORT(-1.00)[-1.000]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20230601]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-arm@freebsd.org]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_TLS_LAST(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::62d:from]; DKIM_TRACE(0.00)[gmail.com:+]; MID_RHS_MATCH_FROMTLD(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCPT_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_ONE(0.00)[1]; MIME_TRACE(0.00)[0:+,1:+,2:~]; MLMMJ_DEST(0.00)[freebsd-arm@freebsd.org] X-Rspamd-Queue-Id: 4SvgbW4l6Vz4ZdQ X-Spamd-Bar: -- --000000000000062155060cde8899 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hello to everyone. I have compiled the needed u-boot.bin from scratch using this procedure : # git clone https://github.com/u-boot/u-boot.git # cd u-boot # ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make snow_defconfig : thi= s line generates the file .config # nano .config and I've added these parameters : CONFIG_ARMV7_NONSEC=3Dn CONFIG_EFI_GRUB_ARM32_WORKAROUND=3Dy the uboot-bin file is generated with this command : # ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make At this point,I took a look inside the .config file and I saw that the parameter "CONFIG_ARMV7_NONSEC=3Dn" has been removed. So,for some reason,it is not accepted and this could be a problem.... These are the xen config files that I've used : nano freebsd.cfg name=3D"test" kernel=3D"u-boot.bin" extra =3D "console=3Dhvc0" memory=3D256 vcpus=3D1 disk =3D [ 'FreeBSD-13.2-RELEASE-armv7.img,raw,xvda' ] nano start-freebsd xl create freebsd.cfg xl console freebsd This is what happens when I launch the vm : # ./start-freebsd Parsing config from freebsd.cfg xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader found: Invalid kernel libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image failed libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 1:cannot (re-)build domain: -3 libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 1:Non-existent domain libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 1:Unable to destroy guest libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 1:Destruction of domain failed freebsd is an invalid domain identifier (rc=3D-6) On Mon, Dec 18, 2023 at 12:39=E2=80=AFPM Mario Marietto wrote: > So,ok,I should have said "the second u-boot" ; since the first u-boot > binary is the "u-boot binary located in the RO memory" of the Chromebook"= . > Sorry for the confusion. > > On Mon, Dec 18, 2023 at 12:35=E2=80=AFPM Mario Marietto > wrote: > >> ---> There are no specific options in u-boot devoted to FreeBSD >> >> This is an important factor. So,what about if,instead of compiling a new >> version of u-boot on the partition 2,I will recompile the u-boot customi= zed >> version created by the virtual open system in 2014,that should be instal= led >> on the first partition ? It could work if there are no differences betwe= en >> the u-boot that should boot Linux and the u-boot that should boot FreeBS= D. >> >> Can you give a look at the u-boot source code created by virtual open >> systems ? You can find it on my google drive : >> >> >> https://drive.google.com/file/d/1eAaZMfd6CU0xiqQfH7sq5wGVzzO09BRm/view?u= sp=3Dsharing >> >> I need to understand if I can recompile it without problem so that it ca= n >> satisfy my needs (the ability of the file u-boot.bin to boot FreeBSD as >> domU under Xen,as explained by Stefano Stabellini,the xen developer that >> suggested to me what I could do to have FreeBSD virtualized under Xen on= my >> Arm Chromebook) ; otherwise the risk is to find later problems that will >> make me troubles and that I will not able to fix. >> >> I gave a look at the virtual open system u-boot and I didn't see any arn= dale_defconfig >> inside. So,If I have understood correctly,I should put that file inside = the >> root of the u-boot source code,let's say here : >> >> marietto:/home/marietto/Desktop/Files/u-boot_FreeBSD/u-boot-vos # ls >> >> .checkpatch.conf README doc >> net >> .git api drivers >> onenand_ipl >> .gitignore arch dts >> post >> COPYING board examples >> rules.mk >> CREDITS boards.cfg fs >> scripts >> MAINTAINERS common include >> snapshot.commit >> MAKEALL config.mk lib >> spl >> Makefile cros mkconfig >> test >> PRESUBMIT.cfg disk nand_spl >> tools >> >> and I should do : make and make install ? and the file I need,u-boot.bin >> will be generated ? >> >> I didn't find any pre made configuration file inside : >> >> u-boot-vos # find . -type f -name "exynos*" >> >> ./include/exynos-fb.h >> ./include/configs/exynos5-common.h >> ./doc/device-tree-bindings/spi/exynos-spi.txt >> ./doc/device-tree-bindings/usb/exynos-usb.txt >> ./drivers/power/exynos-tmu.c >> ./drivers/power/exynos-cpufreq.c >> ./drivers/video/exynos-fb.c >> ./drivers/spi/exynos_spi.c >> ./board/samsung/dts/exynos5250-spring.dts >> ./board/samsung/dts/exynos5250-smdk5250.dts >> ./board/samsung/dts/exynos5250-snow.dts >> ./board/samsung/dts/exynos5250-daisy.dts >> ./arch/arm/include/asm/arch-exynos5/exynos-cpufreq.h >> ./arch/arm/include/asm/arch-exynos5/exynos-tmu.h >> ./arch/arm/dts/exynos5250.dtsi >> ./arch/arm/dts/exynos-periph-id.dtsi >> ./arch/arm/cpu/armv7/exynos5/exynos_cache.c >> >> u-boot-vos # find . -type f -name "arndale*" >> >> For sure I can't use a newer version of u-boot because otherwise the >> patches needed to bypass the bootloader protections of the Arm Chromeboo= k >> (such as a lot of different patches needed to boot correctly Linux) will= be >> broken ; anyway,since it works,I don't need to use an updated version of >> u-boot. >> >> ----> As per my experience, you have to respect these two options, >> compiling u-boot for FreeBSD: >> https://github.com/freebsd/freebsd-ports/blob/main/sysutils/u-boot-maste= r/files/FreeBSD_Fragment >> >> It says that I should use these parameters : >> >> CONFIG_ARMV7_NONSEC=3Dn >> CONFIG_EFI_GRUB_ARM32_WORKAROUND=3Dy >> >> These are the parameters used to configure a Linux kernel. I don't >> understand what's the relation between the compilation of a linux kernel >> and u-boot. In the past I tried to recompile u-boot,but I didn't have th= e >> need to set up those parameters,so I don't know how to do it (but I know >> how to recompile a Linux kernel). >> >> >> ---> I'm not sure that I'm getting you right, as I don't understand what >> you mean under "the first u-boot". >> >> >> I'm talking about first u-boot because the whole procedure to boot Linux >> on the ARM Chromebook,that's explained here : >> >> http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/ >> >> >> at some point they say : >> >> >> To be able to run KVM on ARM platforms, the kernel has to be booted in >> hypervisor mode. Because of this relatively recent requirement (due to t= he >> introduction of the virtualization extensions), up until now all booting >> methods would boot the kernel in the standard Supervisor mode. >> >> For the ARM Chromebook the default boot procedure doesn't allow us to >> boot in hypervisor mode. Although the laptop's boot mechanism is based o= n >> the frequently used u-boot, the binary is located in RO memory. >> Fortunately, a chained u-boot mechanism can be used (i.e. starting anoth= er >> u-boot after the original). We can then enter hypervisor mode from our >> custom iteration of u-boot and subsequently load our kernel and userspac= e. >> >> So,the first u-boot is the u-boot provided by virtual open systems,that'= s >> able to chainload the "u-boot binary located in RO memory" , that does n= ot >> boot Chrome OS in hypervisor mode. We don't need it if we want to boot >> Linux with kvm or xen enabled. >> >> On Sun, Dec 17, 2023 at 1:28=E2=80=AFAM Stanislav Silnicki < >> stanislav.silnicki@mailgate.us> wrote: >> >>> I'm not an expert in the topic, I only know, that ARM has divided >>> hardware into two worlds - Secure and Not-So, strictly limiting any >>> software, running in non-secure world with access to functions and >>> resources. >>> https://developer.arm.com/documentation/den0013/d/Security/TrustZone-ha= rdware-architecture?lang=3Den >>> >>> I'm not sure, that I'm getting you right, as I don't understand what yo= u >>> mean under "the first u-boot". >>> >>> As I understand, virtualization (HYP) is running in non-secure world ( >>> https://developer.arm.com/documentation/ddi0406/c/System-Level-Architec= ture/The-System-Level-Programmers--Model/The-Virtualization-Extensions), >>> so my guess (only guess!!!), virtualization software has to prepare >>> (configure) HW platform in the way, that FreeBSD kernel will not lack a= ny >>> resources, required to configure MPU, VA, etc. >>> So, if you lucky to boot virtualizer, which is aware of target OS, that >>> maybe you can boot the kernel. Although, I doubt, that you need to boot >>> 'second' u-boot to boot the kernel - there is simply ubldr, which you c= an >>> hook somehow from virtualizer.... >>> >>> Stan >>> >>> >>> >>> Mario Marietto wrote: >>> >>> >>> ---> As I understand, it makes sure that u-boot keeps in secure mode >>> during boot and passes control to ubldr, which boots FreeBSD kernel, in >>> that mode. >>> >>> Can you elaborate your sentence more ? I know that the bootloader secur= e >>> mode is bypassed by the virtual open systems u-boot. Are you saying tha= t >>> when the control passes to the second u-boot,it will happen in secure >>> mode,so that the bypass that happened loading the first u-boot,is annul= led >>> ? If this is true,maybe can I boot FreeBSD using the virtual-open-syste= m >>> custom u-boot ? Is this compatible with FreeBSD ? Where can I find the >>> u-boot.bin that the xen developer talked about ? thanks bro'. >>> >>> >>> >>> On Sun, Dec 17, 2023 at 12:35=E2=80=AFAM Stanislav Silnicki < >>> stanislav.silnicki@mailgate.us> wrote: >>> >>>> Hi Mario, >>>> >>>> U-Boot beast is hiding in this den: >>>> https://source.denx.de/u-boot/u-boot.git >>>> I took a brief look at your post and it seems to me, that option >>>> CONFIG_CMO_BY_VA_ONLY is irrelevant to your target armv7 32 bit >>>> platform: >>>> https://source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/cpu/armv8/= Kconfig?ref_type=3Dheads#L3 >>>> >>>> As for compiling the u-boot, it is a doable task, given that you >>>> understand what you are doing. There are no specific options in u-boot >>>> devoted to FreeBSD. It is a boot loader, whose mission to make basic >>>> hardware initialization, read you kernel file from some media into RAM= and >>>> then pass it control. >>>> >>>> Basically, you can grab some defconfig, prepared for any other >>>> Exynos5250 based board (say, this one: >>>> https://source.denx.de/u-boot/u-boot/-/blob/master/configs/arndale_def= config?ref_type=3Dheads) >>>> and adopt it somehow. >>>> >>>> As per my experience, you have to respect these two options, compiling >>>> u-boot for FreeBSD: >>>> https://github.com/freebsd/freebsd-ports/blob/main/sysutils/u-boot-mas= ter/files/FreeBSD_Fragment >>>> >>>> As I understand, it makes sure, that u-boot keeps in secure mode durin= g >>>> boot and passes control to ubldr, which boots FreBSD kernel, in that m= ode. >>>> Otherwise, there a lot of surprises you may realize. >>>> >>>> Hope, this will help to progress you tasks >>>> Stan >>>> >>>> Mario Marietto wrote: >>>> >>>> >>>> Hello. >>>> >>>> I'm trying to boot FreeBSD for arm32 bit as DomU on my ARM Chromebook. >>>> Basically there are two ways to accomplish this task : >>>> >>>> 1) to write a patch that allows the FreeBSD kernel to boot as a zImage >>>> file. This could be accomplished applying this patch to a specific fil= e >>>> that's on the source code of FreeBSD : >>>> >>>> >>>> >>>> https://xenbits.xen.org/gitweb/?p=3Dp...8;hb=3D0782e25d98cc13914727170= 35f986c979edef0c9 >>>> >>>> >>>> >>>> This patch was written by Julien Grall a lot of time ago and now it >>>> does not work anymore. This is the reason : >>>> >>>> >>>> It appears FreeBSD-CURRENT removed the last step converting the kernel >>>> file to kernel.bin. The patch can be readily rebased, but without >>>> kernel.bin that doesn't do too much. >>>> >>>> >>>> >>>> So,without a rebase of that patch the first option is not applicable. >>>> And I'm not able to fix it. >>>> >>>> 2) booting FreeBSD using U-Boot,as explained to me by a xen developer = : >>>> >>>> >>>> I was trying to explain why and how Julien's patch works so that you >>>> could be the one to re-do something similar or fix the patch on the Fr= eeBSD >>>> kernel that you are working with. I am happy to help review and write >>>> patches but I don't work with the FreeBSD kernel so I wouldn't be able= to >>>> help you quickly. However, I might have a suggestion. Do you know if >>>> FreeBSD can be booted by U-Boot ? Because U-Boot definitely boots as X= en on >>>> ARM guest firmware/bootloader. You should be able to build U-Boot and = use >>>> the U-Boot binary as Xen guest kernel, then U-Boot could load FreeBSD = from >>>> disk or network and start it. For instance as domU config file: >>>> >>>> kernel=3D"/home/petalinux/u-boot.bin" >>>> disk =3D [ '/home/petalinux/test.img,raw,xvda' ] >>>> >>>> I know it is important to build u-boot with the following config to >>>> make it work on Xen. >>>> >>>> CONFIG_CMO_BY_VA_ONLY=3Dy >>>> >>>> >>>> >>>> This option seems more doable to me according to my knowledge. But I >>>> need to understand how to do it. >>>> >>>> Well,let's say that on the ARM Chromebook I'm forced to use and instal= l >>>> a customized version of u-boot,created by virtual open systems,because= it >>>> is the only one that allows bypassing its bootloader protection. You c= an >>>> find more information here : >>>> >>>> >>>> http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromeboo= k/?vos=3Dtech >>>> >>>> This is the relevant section to read : >>>> >>>> >>>> Bootloader : >>>> >>>> If you wish to skip this chapter you can download a pre-compiled binar= y >>>> of the bootloader: >>>> >>>> >>>> $ wget >>>> http://www.virtualopensystems.com/downloads/guides/kvm_on_chromebook/n= v_u-boot-snow.kpart >>>> >>>> >>>> To be able to run KVM on ARM platforms, the kernel has to be booted in >>>> hypervisor mode. Because of this relatively recent requirement (due to= the >>>> introduction of the virtualization extensions), up until now all booti= ng >>>> methods would boot the kernel in the standard Supervisor mode. For the= ARM >>>> Chromebook the default boot procedure doesn't allow us to boot in >>>> hypervisor mode. Although the laptop's boot mechanism is based on the >>>> frequently used u-boot, the binary is located in RO memory. Fortunatel= y, a >>>> chained u-boot mechanism can be used (i.e. starting another u-boot aft= er >>>> the original). We can then enter hypervisor mode from our custom itera= tion >>>> of u-boot and subsequently load our kernel and userspace. >>>> >>>> Checkout the needed u-boot code : >>>> >>>> >>>> $ git clone git://github.com/virtualopensystems/u-boot.git$ cd u-boot$ >>>> ./scripts/build.sh >>>> >>>> >>>> If successful, a message about how to copy the bootloader on the USB >>>> flash disk or SD card will appear. We will use it later when preparing= the >>>> boot medium to start our system. If you have followed the Setting up t= he >>>> boot medium chapter and you have a prepared boot device, then you can >>>> update u-boot by running : >>>> >>>> >>>> $ sudo dd if=3Dnv_uboot-snow.kpart of=3D/dev/sdX1 >>>> >>>> >>>> >>>> so,the needed u-boot that we must use should be installed on the first >>>> partition of the sd card. >>>> >>>> There is another relevant section to read : >>>> >>>> >>>> Setting up the boot medium >>>> >>>> Now it is time to copy all the relevant files that we created in the >>>> previous chapters,and use them to boot Chromebook with a different ker= nel >>>> and OS. In all these examples the device /dev/sdX is used. Take extra = care >>>> to change the examples to the device that you have attached. Insert th= e >>>> boot medium on your workstation and carefully execute the following st= ep. >>>> First we need to properly format the boot medium. >>>> >>>> In the uboot source directory : >>>> >>>> >>>> $ sudo ./scripts/sdcard.sh /dev/sdX >>>> >>>> >>>> This will erase all data and create 4 partitions in the medium, along >>>> with copying the u-boot binary to the first partition: >>>> >>>> >>>> Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot) >>>> Partition 2 =3D not used >>>> Partition 3 =3D EXT2 partition for u-boot files (uImage and >>>> exynos5250-snow.dtb) >>>> Partition 4 =3D EXT4 partition for userspace files >>>> >>>> >>>> With u-boot being copied, next is the kernel image and DTB file. From >>>> the kernel source execute : >>>> >>>> >>>> $ mkdir ../mnt/ >>>> $ sudo mount /dev/sdX3 ../mnt/ >>>> $ sudo cp arch/arm/boot/uImage ../mnt/ >>>> $ sudo cp arch/arm/boot/dts/exynos5250-snow.dtb ../mnt/ >>>> $ sudo umount /dev/sdX3 >>>> >>>> >>>> Finally, we have to copy the Ubuntu userspace filesystem that we >>>> created earlier: >>>> >>>> >>>> $ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./precise/* mnt/$ sudo umount >>>> /dev/sdX4 >>>> >>>> >>>> >>>> Now,my idea is to chainload the already chain loaded u-boot created by >>>> V.O.S to the new u-boot that we need for booting FreeBSD and that can = be >>>> installed in the partition n.2,as shown in this scheme,because it is n= ot >>>> used : >>>> >>>> >>>> Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot) >>>> Partition 2 =3D not used (maybe we can install the u-boot for arm 32 >>>> bit,compatible with FreeBSD on this partition) >>>> Partition 3 =3D EXT2 partition for u-boot files (uImage and >>>> exynos5250-snow.dtb) >>>> Partition 4 =3D EXT4 partition for userspace files >>>> >>>> >>>> Take in consideration that default boot string is hardcoded here,in th= e >>>> snow.h file of the custom u-boot created by VOS : >>>> >>>> >>>> >>>> https://github.com/virtualopensyste...18a39b6c177dff58a/include/config= s/snow.h#L101 >>>> >>>> >>>> >>>> and it needs to be recompiled because it should point to the partition >>>> n.2,where I will install the u-boot files as explained here : >>>> >>>> >>>> https://wiki.freebsd.org/arm/Chromebook >>>> >>>> >>>> I have some questions to ask before I start working on this. >>>> >>>> 1) The xen developer said : >>>> >>>> >>>> You should be able to build U-Boot and use the U-Boot binary as Xen >>>> guest kernel... >>>> >>>> >>>> >>>> where is the u-boot binary,according to this document ? >>>> >>>> https://wiki.freebsd.org/arm/Chromebook >>>> >>>> I don't see it. >>>> >>>> >>>> 2) where is the source code of the file that I can get here : >>>> >>>> >>>> http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles= /nv_uboot-snow-simplefb.kpart.bz2 >>>> >>>> I need the source code if I want to recompile u-boot so that it can >>>> point to the partition 4. >>>> >>>> Maybe it can be found on this link : >>>> >>>> http://linux-exynos.org/dist/chromebook/nv_uboot/ >>>> >>>> but it can't be opened.... >>>> >>>> >>>> 3) in this specific scenario the source code of u-boot should run on >>>> arm 32 bit,not on arm 64,because I have the Samsung Chromebook "SNOW" = model >>>> XE303C12,that's powered by a Samsung Exynos 5250 (ARMv7 32 bit Cortex = A15) >>>> Soc. >>>> >>>> >>>> 4) I'm not sure if I can chainload the customized u-boot created by >>>> V.O.S that should be installed on the first partition with the u-boot >>>> tailored for booting FreeBSD that should be installed on the partition= 2.... >>>> >>>> >>>> 5) the xen developer said that u-boot should be compiled enabling this >>>> option : >>>> >>>> >>>> Code: >>>> >>>> CONFIG_CMO_BY_VA_ONLY=3Dy >>>> >>>> >>>> >>>> Well,can you provide some good source that can help me to understand >>>> how I can recompile u-boot for FreeBSD ? thanks. >>>> >>>> -- >>>> Mario. >>>> >>>> >>> >>> -- >>> Mario. >>> >>> >> >> -- >> Mario. >> > > > -- > Mario. > --=20 Mario. --000000000000062155060cde8899 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hello to everyone.

I have compiled the needed u-boot.bin from scratch using this proce= dure :

# git clone <= a href=3D"https://github.com/u-boot/u-boot.git" target=3D"_blank">https://g= ithub.com/u-boot/u-boot.git
# cd u-boot
# ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make snow_de= fconfig : this line generates the file .config
# nano .config and I've= added these parameters :

CONFIG= _ARMV7_NONSEC=3Dn
CONFIG_EFI_GRUB_ARM32_WORKAROUND=3Dy

the uboot-bin file is generated with this command :

<= div># ARCH=3Darm CROSS_COMPILE=3Darm-linux-gn= ueabihf- make

At this point,I took a look inside the .config file and I saw that the=20 parameter "CONFIG_ARMV7_NONSEC=3Dn" has been removed. So,for some= =20 reason,it is not accepted and this could be a problem....
These are the xen config files that I've used :

nano freebsd.cfg

name=3D"test"
kernel=3D"u-boot.bin"
extra =3D "console=3Dhvc0"
memory=3D256
vcpus=3D1
disk =3D [ 'FreeBSD-13.2-RELEASE-armv7.img,raw,xvda' ]

nano start-freebsd

<= /span>
xl create freebsd.cfg
xl console freebsd

This is what happens when I launch the vm :

# ./start-freebsd
=C2=A0
Parsing config from freebsd.c= fg
xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader foun= d: Invalid kernel
libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image fail= ed
libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain= 1:cannot (re-)build domain: -3
libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 1:Non-ex= istent domain
libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 1:Una= ble to destroy guest
libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 1:Destructi= on of domain failed
freebsd is an invalid domain identifier (rc=3D= -6)


On Mon, Dec 18, 2023 at 12:39=E2=80=AFPM Mario Marietto = <marietto2008@gmail.com>= ; wrote:
So,ok,I should have said "the second u-boot" ; since th= e first u-boot binary is the "u-boot binary located in the RO memory&q= uot; of the Chromebook". Sorry for the confusion.

On Mon, Dec 18, 2= 023 at 12:35=E2=80=AFPM Mario Marietto <marietto2008@gmail.com> wrote:
=
---= > There are no specific options in u-boot devoted to=20 FreeBSD

This is an important factor. So,what = about if,instead of compiling a new version of u-boot on the partition 2,I = will recompile the u-boot customized version created by the virtual open sy= stem in 2014,that should be installed on the first partition ? It could wor= k if there are no differences between the u-boot that should boot Linux and= the u-boot that should boot FreeBSD.

Can you give= a look at the u-boot source code created by virtual open systems ? You can= find it on my google drive :


I need to un= derstand if I can recompile it without problem so that it can satisfy my ne= eds (the ability of the file u-boot.bin to boot FreeBSD as domU under Xen,a= s explained by Stefano Stabellini,the xen developer that suggested to me wh= at I could do to have FreeBSD virtualized under Xen on my Arm Chromebook) ;= otherwise the risk is to find later problems that will make me troubles an= d that I will not able to fix.

I gave a look = at the virtual open system u-boot and I didn't see any arndale_de= fconfig inside. So,If I have understood correctly,I should put that file in= side the root of the u-boot source code,let's say here :

marietto:/home/marietto/Desktop/Files/u-boot_FreeBSD/u-boot-vos # l= s
= =C2=A0
.checkpatch.conf =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0README =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0doc =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0net
.git =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0api =C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0drivers =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0onenand_ipl
.gitignore =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0arch =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0dts =C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0post
COPYING =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0board =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0exa= mples =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0rules.mk=
CREDITS =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0boards.cfg =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0fs =C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0scripts
MAINTAINERS =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0common =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0include =C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0snapshot.commit
MAKEALL =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0config.mk =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0lib =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0spl
Makefile =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0cros =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= mkconfig =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0test
PRESUBMIT.cfg =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0disk =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0nand_spl =C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0too= ls

and I should do : make and make install ? and the file I need,u-boot.bi= n will be generated ?=C2=A0

I didn't find any pre made configuration f= ile inside :

u-boot-vos # find . -type f -name "exynos*"=C2=A0

./include/exynos-fb.h
./include/configs/exynos5-common.h
./doc/device-tree-bindings/spi/exynos-spi.txt
./doc/device-tree-bindings/usb/exynos-usb.txt
./drivers/power/exynos-tmu.c
./drivers/power/exynos-cpufreq.c
./drivers/video/exynos-fb.c
./drivers/spi/exynos_spi.c
./board/samsung/dts/exynos5250-spring.dts
./board/samsung/dts/exynos5250-smdk5250.dts
./board/samsung/dts/exynos5250-snow.dts
./board/samsung/dts/exynos5250-daisy.dts
./arch/arm/include/asm/arch-exynos5/exynos-cpufreq.h
./arch/arm/include/asm/arch-exynos5/exynos-tmu.h
./arch/arm/dts/exynos5250.dtsi
./arch/arm/dts/exynos-periph-id.dtsi
./arch/arm/cpu/armv7/exynos5/exynos_cache.c=C2=A0

u-boot-vos # find . -type f -name "a= rndale*"

For sure I can't use a newer version of u-boot because otherwise the= patches needed to bypass the bootloader protections of the Arm Chromebook = (such as a lot of different patches needed to boot correctly Linux) will be= broken ; anyway,since it works,I don't need to use an updated version = of u-boot.

----> As per= my experience, you have to respect=20 these two options, compiling u-boot for FreeBSD:=C2=A0https://github.com/freebsd/freebsd-ports/blo= b/main/sysutils/u-boot-master/files/FreeBSD_Fragment

<= font size=3D"4">
<= div>It says that I should use these parameters :

C= ONFIG_ARMV7_NONSEC=3Dn
CONFIG_EFI_GRUB_ARM32_WORKAROUND=3Dy

These are the parameters used to configure a Linux kernel. I don'= ;t understand what's the relation between the compilation of a linux ke= rnel and u-boot. In the past I tried to recompile u-boot,but I didn't h= ave the need to set up those parameters,so I don't know how to do it (b= ut I know how to recompile a Linux kernel).


---> I'm = not sure that I'm getting you right, as I don't understand what you= mean under "the first u-boot".


I'm talki= ng about first u-boot because the whole procedure to boot Linux on the ARM = Chromebook,that's explained here :

http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/<= /a>


at some point they say :


To be able t= o run KVM on ARM platforms, the kernel has to be booted in hypervisor mode. Because of this relatively recent requirement (due to=20 the introduction of the virtualization extensions), up until now all=20 booting methods would boot the kernel in the standard Supervisor mode.

For the ARM Chromebook the default boot procedure doesn't allow us t= o boot in hypervisor mode. Although the laptop's boot mechanism is based= =20 on the frequently used u-boot, the binary is located in RO memory.=20 Fortunately, a chained u-boot mechanism can be used (i.e. starting=20 another u-boot after the original). We can then enter hypervisor mode=20 from our custom iteration of u-boot and subsequently load our kernel and userspace.

So,the first u-boot is the u-boot provided by virtual= open systems,that's able to chainload the "u-boot binary located = in RO memory" , that does not boot Chrome OS in hypervisor mode. We do= n't need it if we want to boot Linux with kvm or xen enabled.

=

On Sun, Dec 17, 2023 at 1:28=E2=80=AFAM Stanislav Silnicki <stanislav.sil= nicki@mailgate.us> wrote:
=20 =20 =20 =20 =20 =20 =20
I'm not an expert in the topic, I only know, that ARM has div= ided hardware into two worlds - Secure and Not-So, strictly limiting any so= ftware, running in non-secure world with access to functions and resources.= =C2=A0https://devel= oper.arm.com/documentation/den0013/d/Security/TrustZone-hardware-architectu= re?lang=3Den
I'm not sure, = that I'm getting you right, as I don't understand what you mean und= er "the first u-boot".

As= I understand, virtualization (HYP) is running in non-secure world (https://developer.arm.com/documentation/ddi0406/c/System-Lev= el-Architecture/The-System-Level-Programmers--Model/The-Virtualization-Exte= nsions), so my guess (only guess!!!), virtualization software has to pr= epare (configure) HW platform in the way, that FreeBSD kernel will not lack= any resources, required to configure MPU, VA, etc.
So, if you lucky to boot virtualizer, which= is aware of target OS, that maybe you can boot the kernel. Although, I dou= bt, that you need to boot 'second' u-boot to boot the kernel - ther= e is simply ubldr, which you can hook somehow from virtualizer....

Stan

Mario Marietto wrote:


=
--->= ; As=20 I understand, it makes sure that u-boot keeps in secure mode during boot=20 and passes control to ubldr, which boots FreeBSD kernel, in that mode.

Can you elaborate your sentence more ? I know that the= bootloader secure mode is bypassed by the virtual open systems u-boot. Are= you saying that when the control passes to the second u-boot,it will happe= n in secure mode,so that the bypass that happened loading the first u-boot,= is annulled ? If this is true,maybe can I boot FreeBSD using the virtual-op= en-system custom u-boot ? Is this compatible with FreeBSD ? Where can I fin= d the u-boot.bin that the xen developer talked about ? thanks bro'.



On Sun, Dec 17, 2023 at 12:35=E2=80=AFAM S= tanislav Silnicki <stanislav.silnicki@mailgate.us> wrote:
=20 =20 =20 =20 =20 =20 =20
=20 =20 =20 =20 =20 =20 =20
Hi=20 Mario,

U-Boot=C2=A0 beas= t is=20 hiding in this den: https://source.denx.de/u-boot/u-boot.git
I took a brief look at your post and it seems to me, that=20 option=C2=A0CONFIG_CMO_BY_VA_ONLY=C2=A0is irrelevant to=20 your target armv7 32 bit=20 platform:=C2=A0https:/= /source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/cpu/armv8/Kconfig?ref_= type=3Dheads#L3

As=20 for compiling the u-boot, it is a doable task, given that you understand=20 what you are doing. There are no specific options in u-boot devoted to=20 FreeBSD. It is a boot loader, whose mission to make basic hardware=20 initialization, read you kernel file from some media into RAM and then pass= =20 it control.

Basically, you can grab some defconfig,=20 prepared for any other Exynos5250 based board=C2=A0 (say, this one: https://source.denx.de/u-boot/u-= boot/-/blob/master/configs/arndale_defconfig?ref_type=3Dheads)=20 and adopt it somehow.

As per my experience, you have to respect=20 these two options, compiling u-boot for FreeBSD:=C2=A0https://github.com/freebsd/freebsd-ports/blo= b/main/sysutils/u-boot-master/files/FreeBSD_Fragment

As=20 I understand, it makes sure, that u-boot keeps in secure mode during boot= =20 and passes control to ubldr, which boots FreBSD kernel, in that mode.=20 Otherwise, there a lot of surprises you may realize.

Hope, this=20 will help to progress you tasks
Stan

Ma= rio=20 Marietto wrote:


Hello.

I'm trying to boot FreeBSD for arm32 bit as DomU on my ARM Chromebook.= =20 Basically there are two ways to accomplish this task :

1) to write a patch that allows the FreeBSD kernel to boot as a zImage=20 file. This could be accomplished applying this patch to a specific file=20 that's on the source code of FreeBSD :


https://xenbits.xen.org/gitweb/?p=3Dp...8;hb= =3D0782e25d98cc1391472717035f986c979edef0c9


This patch was written by Julien Grall a lot of time ago and now it does=20 not work anymore. This is the reason :


=09
=09
It appears FreeBSD-CURRENT removed the last step converting the=20 kernel file to kernel.bin. The patch can be readily rebased, but without kernel.bin that doesn't do too much.
=09


So,without a rebase of that patch the first option is not applicable. And= =20 I'm not able to fix it.

2) booting FreeBSD using U-Boot,as explained to me by a xen developer :


=09
=09
I was trying to explain why and how Julien's patch works so that you= =20 could be the one to re-do something similar or fix the patch on the=20 FreeBSD kernel that you are working with. I am happy to help review and=20 write patches but I don't work with the FreeBSD kernel so I wouldn'= t be=20 able to help you quickly. However, I might have a suggestion. Do you=20 know if FreeBSD can be booted by U-Boot ? Because U-Boot definitely=20 boots as Xen on ARM guest firmware/bootloader. You should be able to=20 build U-Boot and use the U-Boot binary as Xen guest kernel, then U-Boot=20 could load FreeBSD from disk or network and start it. For instance as=20 domU config file:

kernel=3D"/home/petalinux/u-boot.bin"
disk =3D [ '/home/petalinux/test.img,raw,xvda' ]

I know it is important to build u-boot with the following config to make it= =20 work on Xen.

CONFIG_CMO_BY_VA_ONLY=3Dy
=09


This option seems more doable to me according to my knowledge. But I need= =20 to understand how to do it.

Well,let's say that on the ARM Chromebook I'm forced to use and ins= tall a customized version of u-boot,created by virtual open systems,because it is the only one that allows bypassing its bootloader protection. You=20 can find more information here :

http:/= /www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/?vos=3Dte= ch

This is the relevant section to read :


=09
=09
Bootloader :

If you wish to skip this chapter you can download a pre-compiled binary of= =20 the bootloader:


$ wget http://www.virtualopensystems.com/downloads/guides/kvm_on_chromebook= /nv_u-boot-snow.kpart


To be able to run KVM on ARM platforms, the kernel has to be booted in=20 hypervisor mode. Because of this relatively recent requirement (due to=20 the introduction of the virtualization extensions), up until now all=20 booting methods would boot the kernel in the standard Supervisor mode.=20 For the ARM Chromebook the default boot procedure doesn't allow us to= =20 boot in hypervisor mode. Although the laptop's boot mechanism is based= =20 on the frequently used u-boot, the binary is located in RO memory.=20 Fortunately, a chained u-boot mechanism can be used (i.e. starting=20 another u-boot after the original). We can then enter hypervisor mode=20 from our custom iteration of u-boot and subsequently load our kernel and userspace.

Checkout the needed u-boot code :


$ git clone git://github.com/virtualopensystems/u-boot.git$ c= d=20 u-boot$ ./scripts/build.sh


If successful, a message about how to copy the bootloader on the USB=20 flash disk or SD card will appear. We will use it later when preparing=20 the boot medium to start our system. If you have followed the Setting up the boot medium chapter and you have a prepared boot device, then you=20 can update u-boot by running :


$ sudo dd if=3Dnv_uboot-snow.kpart of=3D/dev/sdX1
=09


so,the needed u-boot that we must use should be installed on the first=20 partition of the sd card.

There is another relevant section to read :


=09
=09
Setting up the boot medium

Now it is time to copy all the relevant files that we created in the=20 previous chapters,and use them to boot Chromebook with a different=20 kernel and OS. In all these examples the device /dev/sdX is used. Take=20 extra care to change the examples to the device that you have attached.=20 Insert the boot medium on your workstation and carefully execute the=20 following step. First we need to properly format the boot medium.

In the uboot source directory :


$ sudo ./scripts/sdcard.sh /dev/sdX


This will erase all data and create 4 partitions in the medium, along with= =20 copying the u-boot binary to the first partition:


Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot)
Partition 2 =3D not used
Partition 3 =3D EXT2 partition for u-boot files (uImage and=20 exynos5250-snow.dtb)
Partition 4 =3D EXT4 partition for userspace files


With u-boot being copied, next is the kernel image and DTB file. From the= =20 kernel source execute :


$ mkdir ../mnt/
$ sudo mount /dev/sdX3 ../mnt/
$ sudo cp arch/arm/boot/uImage ../mnt/
$ sudo cp arch/arm/boot/dts/exynos5250-snow.dtb ../mnt/
$ sudo umount /dev/sdX3


Finally, we have to copy the Ubuntu userspace filesystem that we created=20 earlier:


$ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./precise/* mnt/$ sudo umount=20 /dev/sdX4
=09


Now,my idea is to chainload the already chain loaded u-boot created by=20 V.O.S to the new u-boot that we need for booting FreeBSD and that can be installed in the partition n.2,as shown in this scheme,because it is=20 not used :


Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot)
Partition 2 =3D not used (maybe we can install the u-boot for arm 32=20 bit,compatible with FreeBSD on this partition)
Partition 3 =3D EXT2 partition for u-boot files (uImage and=20 exynos5250-snow.dtb)
Partition 4 =3D EXT4 partition for userspace files


Take in consideration that default boot string is hardcoded here,in the=20 snow.h file of the custom u-boot created by VOS :


https://github.com/virtualopensyste...18a39b6c= 177dff58a/include/configs/snow.h#L101


and it needs to be recompiled because it should point to the partition=20 n.2,where I will install the u-boot files as explained here :


https://wiki.freebsd.org/arm/Chromebook


I have some questions to ask before I start working on this.

1) The xen developer said :


=09
=09
You should be able to build U-Boot and use the U-Boot binary as Xen=20 guest kernel...
=09


where is the u-boot binary,according to this document ?

https://wiki.freebsd.org/arm/Chromebook

I don't see it.


2) where is the source code of the file that I can get here :

http://commondatastorage.googleapis.com/chromeos-localmirror/dist= files/nv_uboot-snow-simplefb.kpart.bz2

I need the source code if I want to recompile u-boot so that it can point= =20 to the partition 4.

Maybe it can be found on this link :

http://linux-exynos.org/dist/chromebook/nv_= uboot/

but it can't be opened....


3) in this specific scenario the source code of u-boot should run on arm 32 bit,not on arm 64,because I have the Samsung Chromebook "SNOW&quo= t; model XE303C12,that's powered by a Samsung Exynos 5250 (ARMv7 32 bit Cortex= =20 A15) Soc.


4) I'm not sure if I can chainload the customized u-boot created by=20 V.O.S that should be installed on the first partition with the u-boot=20 tailored for booting FreeBSD that should be installed on the partition=20 2....


5) the xen developer said that u-boot should be compiled enabling this=20 option :


=09 =09
Code: 

CONFIG_CMO_BY_VA_ONLY=3Dy


Well,can you provide some good source that can help me to understand how I= =20 can recompile u-boot for FreeBSD ?=20 thanks.
=

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Mario.
=20 =20 =20
=20 =20


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Mario.
=20 =20 =20

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Mario.


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Mario.


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Mario.
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