From nobody Tue Dec 19 17:07:40 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 4Svjnf2XZRz54Z6r for ; Tue, 19 Dec 2023 17:08:22 +0000 (UTC) (envelope-from marietto2008@gmail.com) Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) (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 4Svjnc0HCpz3CjQ for ; Tue, 19 Dec 2023 17:08:20 +0000 (UTC) (envelope-from marietto2008@gmail.com) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20230601 header.b=XgaNmglk; spf=pass (mx1.freebsd.org: domain of marietto2008@gmail.com designates 2a00:1450:4864:20::636 as permitted sender) smtp.mailfrom=marietto2008@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-ej1-x636.google.com with SMTP id a640c23a62f3a-a2685675b6eso73992766b.1 for ; Tue, 19 Dec 2023 09:08:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1703005698; x=1703610498; 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=XAYgT2jNeVpzPjD39EIIMgS97rrRHtBAJD704cGdbq0=; b=XgaNmglkGD+hs+4LbiJ4pfS6TkKl+Z2h7MIz0ptug6lHz5/pHEFWZ8JTqSfSXUQJKQ HHs6PbqGwC+bQPzHWuRstNpJMiwaGvmY754qhz1vZmIyG9VGD8DGHcI6CQa3hQAYF35J 99V6K9lOnNN0t4VBS8V1UbG/Me224IBavP/FiGCsWkJKMKAVQTJVkYX3sNTkcsDg7qY4 WuPoRpeGlWvjxnlp5AzgpZmCa1S8sjqqDL26U86yK13NTRxCZoNlKQgeSVUpkb2JD+MX OA8YOoauZkoiQIaJXWQU9zYqmlwUIzpP/v2O5hCwq9I74iu/2Lua4YnbiPgLddsRZ8qB BfHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703005698; x=1703610498; 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=XAYgT2jNeVpzPjD39EIIMgS97rrRHtBAJD704cGdbq0=; b=cX2G2xmFekZtquZo47Ja2BPbh9yoJOF25okFiH1fq7xH+BOwtVgzRFTeg4kb/DJldf 4WfeBDefHqDauUFPYozQrDTexjMyxfoxjz9+tLHguJmjm6XcCxguFhDICTCA36L5Ktgp Rv25uit91Gp0j2pHqbQ/QTn3c0l/ZWjTQTLSsBSmM+8ous7BjewmddWCZYSZJYMjfNwp pAKieV5AD3+pFN1YG+xxEEB79sSlRvWmGB2Mo5NGcyUwbPnpB8OaK8unD51Lm5hncKSr JDC2DezUNUDmjkFHXvjmOItsHZ0LWkfTy2yr6kATChVF7elA5WU4fkusSwQxRZK1QxNS ExpQ== X-Gm-Message-State: AOJu0YwnJslt+YVPRidDpg3KWHaE/D90jYPdsnavc/DrjwbbRr53OaXd 7q3QCxVzFmmgef+Pgpmi1/x8Wsecxpj9f+EpKDQ= X-Google-Smtp-Source: AGHT+IF+zm7XepDWGiGAiueHx9EHODiFv9vuxWPM2PmTRkHWk7kWNVh6/lO4T4uE1TMMVJWpPKW7IkEeUleYZD6Enj0= X-Received: by 2002:a17:906:7247:b0:a23:5fa8:6ec1 with SMTP id n7-20020a170906724700b00a235fa86ec1mr1250003ejk.19.1703005697401; Tue, 19 Dec 2023 09:08:17 -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 18:07:40 +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 , Stefano Stabellini Cc: freebsd-arm@freebsd.org Content-Type: multipart/alternative; boundary="000000000000a4e847060cdfe9f8" X-Spamd-Result: default: False [-2.96 / 15.00]; URI_COUNT_ODD(1.00)[69]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.96)[-0.964]; 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]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-arm@freebsd.org]; ARC_NA(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::636:from]; DKIM_TRACE(0.00)[gmail.com:+]; MID_RHS_MATCH_FROMTLD(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; RCVD_TLS_LAST(0.00)[]; RCVD_COUNT_ONE(0.00)[1]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FROM_EQ_ENVFROM(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; MLMMJ_DEST(0.00)[freebsd-arm@freebsd.org] X-Rspamd-Queue-Id: 4Svjnc0HCpz3CjQ X-Spamd-Bar: -- --000000000000a4e847060cdfe9f8 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ....I see that some other interesting files have been produced by u-boot when I have compiled it : u-boot u-boot.lds u-boot.bin u-boot.map u-boot-nodtb.bin u-boot.dtb u-boot.srec u-boot-dtb.bin u-boot.sym So,maybe I should use a different u-boot* file for booting FreeBSD ? On Tue, Dec 19, 2023 at 4:28=E2=80=AFPM Mario Marietto wrote: > 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 : t= his > 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:Unabl= e > 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 ne= w >>> version of u-boot on the partition 2,I will recompile the u-boot custom= ized >>> version created by the virtual open system in 2014,that should be insta= lled >>> on the first partition ? It could work if there are no differences betw= een >>> the u-boot that should boot Linux and the u-boot that should boot FreeB= SD. >>> >>> 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?= usp=3Dsharing >>> >>> I need to understand if I can recompile it without problem so that it >>> can satisfy my needs (the ability of the file u-boot.bin to boot FreeBS= D as >>> domU under Xen,as explained by Stefano Stabellini,the xen developer tha= t >>> suggested to me what I could do to have FreeBSD virtualized under Xen o= n my >>> Arm Chromebook) ; otherwise the risk is to find later problems that wil= l >>> 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 ar= ndale_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.bi= n >>> 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 Chromebo= ok >>> (such as a lot of different patches needed to boot correctly Linux) wil= l be >>> broken ; anyway,since it works,I don't need to use an updated version o= f >>> 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-mast= er/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 kerne= l >>> and u-boot. In the past I tried to recompile u-boot,but I didn't have t= he >>> need to set up those parameters,so I don't know how to do it (but I kno= w >>> how to recompile a Linux kernel). >>> >>> >>> ---> I'm not sure that I'm getting you right, as I don't understand wha= t >>> you mean under "the first u-boot". >>> >>> >>> I'm talking about first u-boot because the whole procedure to boot Linu= x >>> 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 = the >>> introduction of the virtualization extensions), up until now all bootin= g >>> 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. >>> Fortunately, a chained u-boot mechanism can be used (i.e. starting anot= her >>> u-boot after the original). We can then enter hypervisor mode from our >>> custom iteration of u-boot and subsequently load our kernel and userspa= ce. >>> >>> 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 memor= y" , >>> that does not 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-h= ardware-architecture?lang=3Den >>>> >>>> I'm not sure, that I'm getting you right, as I don't understand what >>>> you 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-Archite= cture/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 = any >>>> resources, required to configure MPU, VA, etc. >>>> So, if you lucky to boot virtualizer, which is aware of target OS, tha= t >>>> maybe you can boot the kernel. Although, I doubt, that you need to boo= t >>>> 'second' u-boot to boot the kernel - there is simply ubldr, which you = can >>>> 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, i= n >>>> 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 sa= ying >>>> that when the control passes to the second u-boot,it will happen in se= cure >>>> mode,so that the bypass that happened loading the first u-boot,is annu= lled >>>> ? If this is true,maybe can I boot FreeBSD using the virtual-open-syst= em >>>> 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-boo= t >>>>> devoted to FreeBSD. It is a boot loader, whose mission to make basic >>>>> hardware initialization, read you kernel file from some media into RA= M 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_de= fconfig?ref_type=3Dheads) >>>>> and adopt it somehow. >>>>> >>>>> As per my experience, you have to respect these two options, compilin= g >>>>> u-boot for FreeBSD: >>>>> https://github.com/freebsd/freebsd-ports/blob/main/sysutils/u-boot-ma= ster/files/FreeBSD_Fragment >>>>> >>>>> As I understand, it makes sure, that u-boot keeps in secure mode >>>>> during boot and passes control to ubldr, which boots FreBSD kernel, i= n that >>>>> mode. 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 zImag= e >>>>> file. This could be accomplished applying this patch to a specific fi= le >>>>> that's on the source code of FreeBSD : >>>>> >>>>> >>>>> >>>>> https://xenbits.xen.org/gitweb/?p=3Dp...8;hb=3D0782e25d98cc1391472717= 035f986c979edef0c9 >>>>> >>>>> >>>>> >>>>> 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 kerne= l >>>>> 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 F= reeBSD >>>>> 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 abl= e 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 = Xen 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 >>>>> install a customized version of u-boot,created by virtual open >>>>> systems,because it is the only one that allows bypassing its bootload= er >>>>> protection. You can find more information here : >>>>> >>>>> >>>>> http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebo= ok/?vos=3Dtech >>>>> >>>>> This is the relevant section to read : >>>>> >>>>> >>>>> Bootloader : >>>>> >>>>> If you wish to skip this chapter you can download a pre-compiled >>>>> binary of 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 i= n >>>>> hypervisor mode. Because of this relatively recent requirement (due t= o the >>>>> introduction of the virtualization extensions), up until now all boot= ing >>>>> methods would boot the kernel in the standard Supervisor mode. For th= e 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. Fortunate= ly, a >>>>> chained u-boot mechanism can be used (i.e. starting another u-boot af= ter >>>>> the original). We can then enter hypervisor mode from our custom iter= ation >>>>> 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 preparin= g 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 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 firs= t >>>>> 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 ke= rnel >>>>> 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 t= he >>>>> boot medium on your workstation and carefully execute the following s= tep. >>>>> 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 b= y >>>>> 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 = 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 >>>>> 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 >>>>> the snow.h file of the custom u-boot created by VOS : >>>>> >>>>> >>>>> >>>>> https://github.com/virtualopensyste...18a39b6c177dff58a/include/confi= gs/snow.h#L101 >>>>> >>>>> >>>>> >>>>> and it needs to be recompiled because it should point to the partitio= n >>>>> 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/distfile= s/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 partitio= n 2.... >>>>> >>>>> >>>>> 5) the xen developer said that u-boot should be compiled enabling thi= s >>>>> 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. >> > > > -- > Mario. > --=20 Mario. --000000000000a4e847060cdfe9f8 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
..= ..I see that some other interesting files have been produced by u-boot when= I have compiled it :

u-boot
u-boot.lds
u-boot.bin
= u-boot.map
u-bo= ot-nodtb.bin
u-boot.dtb
u-boot.srec=
u-boot-dtb.bin
= u-boot.sym

So,maybe I sho= uld use a different u-boot* file for booting FreeBSD ?


=
On Tue, Dec 19, 2023 at 4:28=E2=80=AF= PM Mario Marietto <marietto200= 8@gmail.com> wrote:
Hello to everyone.
<= div>
I have compiled the needed u-boot.bin from scratch using= this procedure :

# cd u-boot
# ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make <= /span>snow_defconfig : 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

xl create freebsd.cfg
xl console freebsd

This is what happens when I launch the vm :

# ./start-freebsd
=C2=A0
Parsing config from freebsd.cfg
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)
<= br>

On Mon, Dec 18, 2023 at 12:39=E2=80=AFPM Mario M= arietto <mar= ietto2008@gmail.com> wrote:
So,ok,I should have said "the seco= nd u-boot" ; since the first u-boot binary is the "u-boot binary = located in the RO memory" of the Chromebook". Sorry for the confu= sion.

On Mon, Dec 18, 2023 at 12:35=E2=80=AFPM Mario Marietto <marietto2008@gmail.co= m> wrote:
---> There are no specific options in u-boot devo= ted 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 talking about first u-boot because the whole procedure to b= oot Linux on the ARM Chromebook,that's explained here :

http://www.virtualopensystems.com/en/solutions/guide= s/kvm-on-chromebook/


at some point they say :

To be able to run KVM on ARM platforms, the kernel has to be boote= d 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 kn= ow, that ARM has divided hardware into two worlds - Secure and Not-So, stri= ctly limiting any software, running in non-secure world with access to func= tions and resources.=C2=A0https://developer.arm.com/documentation/den0013/d/Security/TrustZone= -hardware-architecture?lang=3Den

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

As I understand, virtualization (HYP) is running= in non-secure world (https://developer.arm.com/docum= entation/ddi0406/c/System-Level-Architecture/The-System-Level-Programmers--= Model/The-Virtualization-Extensions), so my guess (only guess!!!), virt= ualization software has to prepare (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, t= hat 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 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, yo= u 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

Mario=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.

<= /div>
--
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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