From nobody Wed Dec 20 18:26:06 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 4SwMTh5PpWz55CnZ for ; Wed, 20 Dec 2023 18:26:48 +0000 (UTC) (envelope-from marietto2008@gmail.com) Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) (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 4SwMTg2CxNz3C6H for ; Wed, 20 Dec 2023 18:26:47 +0000 (UTC) (envelope-from marietto2008@gmail.com) Authentication-Results: mx1.freebsd.org; none Received: by mail-ed1-x52a.google.com with SMTP id 4fb4d7f45d1cf-5533ca9cc00so5682152a12.2 for ; Wed, 20 Dec 2023 10:26:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1703096805; x=1703701605; 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=aMWXI25JlXGCWFl4dQxmcQI9big3lNe9jqDk4SHcohs=; b=e4aOLWPIXRvdMN41c+DehmqzPJyVqmHwZM7uQoCfbbZ7UFvdpfeLjvzQ8PW2GM87i7 sScH5Z4kxPbqOiReD/uAaDbU8cfGRpCGBe4igA/8GEWVnmFW3G4TFuJjpuAhcWhjm1ct vyNMtY8LQRNO5iZhO+//YcQJ/+DJ5PJOwml+69jOQ62Ouro5rJ/4gL58VVUxMrdCZUnq ejCXUlUxQoWWDRPsX0wyzXa/jNq8veykiQCV/uFli9BgezT+YO89OLUKP3kC2LnMVR5G wLu0QA/OaMgw+owKseewS5PEI9QkRq2/Iaz5h/vtqlya7OzLy6+ZhpkSy6mucm0Kq7z/ T6JQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703096805; x=1703701605; 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=aMWXI25JlXGCWFl4dQxmcQI9big3lNe9jqDk4SHcohs=; b=rTBwViDtfEeZadkgyG1oJAx186i0Di1L9orpCSrRlEgB3cO/ui8Yw3zAIU34cgmFZs SE0NBEq+Idb5MyuBRiW2YhVzZgRKwcQughD/s181ZKZC3U/4uRmad4VknuFaq2y5780h lKUnFYOBLcYhCp9M/XNc7qKpv0u2PfgC0RRL4FMPX6ZD5OOMPp1ZHTQiIiqYiq90Qh0L VJRrskqf3M5OaCSiXdocp0dak75XTmh0ygkCb+Hyft5NOhLA3BKX/RH0gMphKK2BNdH/ sLO+ANXV3HsYP8AWmWoKWloMi/+3g67GUIkYRMF4ed5nrcpNwCfwb3bCyCXv77SOfSkV 5SGA== X-Gm-Message-State: AOJu0YxTwjjvmubDVfWyayLS7U4IKrBb+YfcD7AHuSOPG1kOT/a2HSPc t5Ll8cD+KZy92ovv8hpTgOfDkADz6UJlUB0xwgE= X-Google-Smtp-Source: AGHT+IHQB2dbUu9rzwymoPiGnkxccwWTbjyR12ZBIOUfVCWuN4HLHeoNPJ48mVqTx4X7nL2JQmvBLcgORoHf4xa0Ack= X-Received: by 2002:a17:907:970e:b0:a23:49ec:e09b with SMTP id jg14-20020a170907970e00b00a2349ece09bmr4095247ejc.18.1703096804650; Wed, 20 Dec 2023 10:26:44 -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> <54b70672-9ea4-40e2-b346-b579536c0e5c@mailgate.us> In-Reply-To: <54b70672-9ea4-40e2-b346-b579536c0e5c@mailgate.us> From: Mario Marietto Date: Wed, 20 Dec 2023 19:26:06 +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="0000000000000f32f8060cf520da" X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US] X-Spamd-Bar: ---- X-Rspamd-Queue-Id: 4SwMTg2CxNz3C6H --0000000000000f32f8060cf520da Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ---> Mario, you can not edit .config by hand. You have to consider these options in some _defconfig and then reconfigure / recompile ok. I did as you have suggested,but I've got the same exact error. I've added the parameter "CONFIG_ARMV7_NONSEC=3Dn" inside the file snow_defconfi= g and then : # ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make snow_defconfig # ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make The u-boot.bin file generated has a different size than that generated before,but the error when I try to boot FreeBSD is the same. On Wed, Dec 20, 2023 at 6:00=E2=80=AFPM Stanislav Silnicki < stanislav.silnicki@mailgate.us> wrote: > Mario, you can not edit .config byhand. You have to consider these option= s > in some _defconfig and then reconfigure/tecompile > > Get BlueMail for Android > On Dec 19, 2023, at 5:29 PM, 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 : = 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 : >> >> # 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 faile= d >> libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 1:canno= t >> (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:Destructio= n >> 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 Chromeboo= k". >>> 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 >>>> customized version created by the virtual open system in 2014,that sho= uld >>>> be installed on the first partition ? It could work if there are no >>>> differences between the u-boot that should boot Linux and the u-boot t= hat >>>> 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 : >>>> >>>> >>>> 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 FreeB= SD as >>>> domU under Xen,as explained by Stefano Stabellini,the xen developer th= at >>>> 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 wi= ll >>>> 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 a= rndale_defconfig >>>> inside. So,If I have understood correctly,I should put that file insid= e 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 Chromeb= ook >>>> (such as a lot of different patches needed to boot correctly Linux) wi= ll 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-mas= ter/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 kern= el >>>> and u-boot. In the past I tried to recompile u-boot,but I didn't have = the >>>> need to set up those parameters,so I don't know how to do it (but I kn= ow >>>> 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-chromeboo= k/ >>>> >>>> >>>> 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 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. >>>> Fortunately, a chained u-boot mechanism can be used (i.e. starting ano= ther >>>> u-boot after the original). We can then enter hypervisor mode from our >>>> custom iteration of u-boot and subsequently load our kernel and usersp= ace. >>>> >>>> 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 memo= ry" , >>>> that does not boot Chrome OS in hypervisor mode. We don't need it if w= e >>>> 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-= 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/documentation/ddi0406/c/System-Level-Archit= ecture/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, >>>>> 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, whic= h 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, = 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 s= aying >>>>> that when the control passes to the second u-boot,it will happen in s= ecure >>>>> mode,so that the bypass that happened loading the first u-boot,is ann= ulled >>>>> ? If this is true,maybe can I boot FreeBSD using the virtual-open-sys= tem >>>>> custom u-boot ? Is this compatible with FreeBSD ? Where can I find th= e >>>>> 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/armv= 8/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-bo= ot >>>>>> devoted to FreeBSD. It is a boot loader, whose mission to make basic >>>>>> hardware initialization, read you kernel file from some media into R= AM 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_d= efconfig?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-m= aster/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, = in 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 >>>>>> zImage file. This could be accomplished applying this patch to a spe= cific >>>>>> file that's on the source code of FreeBSD : >>>>>> >>>>>> >>>>>> >>>>>> https://xenbits.xen.org/gitweb/?p=3Dp...8;hb=3D0782e25d98cc139147271= 7035f986c979edef0c9 >>>>>> >>>>>> >>>>>> >>>>>> 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 wit= hout >>>>>> 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 develope= r >>>>>> : >>>>>> >>>>>> >>>>>> 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 = FreeBSD >>>>>> kernel that you are working with. I am happy to help review and writ= e >>>>>> patches but I don't work with the FreeBSD kernel so I wouldn't be ab= le 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 an= d use >>>>>> the U-Boot binary as Xen guest kernel, then U-Boot could load FreeBS= D 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 bootloa= der >>>>>> protection. You can find more information here : >>>>>> >>>>>> >>>>>> http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromeb= ook/?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 >>>>>> in hypervisor mode. Because of this relatively recent requirement (d= ue to >>>>>> the introduction of the virtualization extensions), up until now all >>>>>> booting methods would boot the kernel in the standard Supervisor mod= e. For >>>>>> the ARM Chromebook the default boot procedure doesn't allow us to bo= ot in >>>>>> hypervisor mode. Although the laptop's boot mechanism is based on th= e >>>>>> frequently used u-boot, the binary is located in RO memory. Fortunat= ely, a >>>>>> chained u-boot mechanism can be used (i.e. starting another u-boot a= fter >>>>>> the original). We can then enter hypervisor mode from our custom ite= ration >>>>>> 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 prepari= ng 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 ca= n >>>>>> 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 k= ernel >>>>>> and OS. In all these examples the device /dev/sdX is used. Take extr= a care >>>>>> to change the examples to the device that you have attached. Insert = the >>>>>> boot medium on your workstation and carefully execute the 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, alon= g >>>>>> 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. Fro= m >>>>>> 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 umoun= t >>>>>> /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= 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/conf= igs/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 her= e : >>>>>> >>>>>> >>>>>> 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/distfil= es/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 Corte= x 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-boo= t >>>>>> tailored for booting FreeBSD that should be installed on the partiti= on >>>>>> 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. >>> >> >> >> -- >> Mario. >> > --=20 Mario. --0000000000000f32f8060cf520da Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
---> Mario, you can not edit .config b= y hand. You have to consider these options in some _defconfig and then reco= nfigure / recompile

ok. I did as you have suggeste= d,but I've got the same exact error. I've added the parameter "= ;CONFIG_ARMV7_NONSEC=3Dn" inside the file snow_defconfig and then :

# ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make snow_defconfig
# ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnueabihf- make

The u-boot.bin file generated has a diffe= rent size than that generated before,but the error when I try to boot FreeB= SD is the same.

On Wed, Dec 20, 2023 at 6:00=E2=80=AFPM Stani= slav Silnicki <stanisl= av.silnicki@mailgate.us> wrote:
Mario, you can not edit .conf= ig byhand. You have to consider these options in some _defconfig and then r= econfigure/tecompile

On Dec 19, 2023, at 5:29 PM, Mario Marietto <= marietto2008@gm= ail.com> wrote:
Hello to everyone.

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

# cd u-boot
# ARCH=3Darm CROSS_COMPILE=3Darm-linux-gnu= eabihf- make snow_defconfig : this line generates the file .config
# nano .config and I've added these pa= rameters :

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-gnu= eabihf- make

At this point,I took a look inside the .config file and I saw that the p= arameter "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=3Dhvc= 0"
memory=3D256
vcpus=3D1
disk =3D [ 'FreeBSD-13.2-RELEASE-armv7.img,ra= w,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 fou= nd: Invalid kernel
libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image fai= led
libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Do= main 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&g= t; 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 <marietto2008@gmail.com= > wrote:
---> There are no specific options in u-boot devoted to FreeBSD=20

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 custom= ized version created by the virtual open system in 2014,that should be inst= alled on the first partition ? It could work if there are no differences be= tween the u-boot that should boot Linux and the u-boot that should boot Fre= eBSD.

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 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 FreeBSD a= s 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 m= ake me troubles and that I will not able to fix.=20

I gave a look at the virtual open system u-boot and I didn't see = any arndale_defconfig inside. So,If I have understood correctly,I sho= uld put that file inside the root of the u-boot source code,let's say h= ere :

marietto:/home/mari= etto/Desktop/Files/u-boot_FreeBSD/u-boot-vos # ls
=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=A0= examples =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= =A0mkconfig =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=A0= tools

and I should = do : make and make install ? and the file I need,u-boot.bin will be generat= ed ?=C2=A0

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

u-boot-vos # find . -type f -name "exynos*<= /span>"=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 . -typ= e f -name "arndale*"=

For sure I ca= n'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 o= f 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:=C2=A0https://github.com/freebsd/freebsd-ports/blob/main/sysutils/u= -boot-master/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 k= ernel. I don't understand what's the relation between the compilati= on of a linux kernel and u-boot. In the past I tried to recompile u-boot,bu= t I didn't have the 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= 9;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 boot= ed in 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 the ARM Chromebook the default boot procedure doesn't all= ow 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 another= u-boot after the original). We can then enter hypervisor mode from our cus= tom iteration of u-boot and subsequently load our kernel and userspace.

So,the first u-boot is the u-boot provided by virtual open system= s,that's able to chainload the "u-boot binary located in RO memory= " , 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.sil= nicki@mailgate.us> wrote:
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 under "the first u-boot".

As I understand, virtualization (HYP) is running in non-secure wo= rld (https://developer.arm.com/documentation/ddi0406/= c/System-Level-Architecture/The-System-Level-Programmers--Model/The-Virtual= ization-Extensions), so my guess (only guess!!!), virtualization softwa= re has to prepare (configure) HW platform in the way, that FreeBSD kernel w= ill 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 doubt, that you need to b= oot 'second' u-boot to boot the kernel - there is simply ubldr, whi= ch you can hook somehow from virtualizer....

Stan



Mario Marietto wrote:


---> As I understand, it makes sure that u-boot keeps in sec= ure mode during boot and passes control to ubldr, which boots FreeBSD kerne= l, in that mode.

Can you elaborate your sentence more ? I know that the bootload= er secure mode is bypassed by the virtual open systems u-boot. Are you sayi= ng that when the control passes to the second u-boot,it will happen in secu= re mode,so that the bypass that happened loading the first u-boot,is annull= ed ? If this is true,maybe can I boot FreeBSD using the virtual-open-system= custom u-boot ? Is this compatible with FreeBSD ? Where can I find the u-b= oot.bin that the xen developer talked about ? thanks bro'.



On Sun, Dec 17, 2023 at 12:35=E2=80=AFAM Stanislav Silnicki <= ;stanis= lav.silnicki@mailgate.us> wrote:
Hi Mario,

U-Boot=C2=A0 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=C2=A0CONFIG_CMO_BY_VA_ONLY=C2=A0is irrelevant to your target armv7= 32 bit platform:=C2=A0https://source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/cpu/armv8/Kcon= fig?ref_type=3Dheads#L3

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

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

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

As I understand, it makes sure, that u-boot keeps in secur= e mode during boot and passes control to ubldr, which boots FreBSD kernel, = in 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 Do= mU on my ARM Chromebook. Basically there are two ways to accomplish this ta= sk :

1) to write a patch that allows the FreeBSD kernel= to boot as a zImage file. This could be accomplished applying this patch t= o a specific file that's on the source code of FreeBSD :


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


This patch was written by Julien Grall a lot of ti= me 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 FreeBSD kernel that you are working with. I am happy to h= elp review and write patches but I don't work with the FreeBSD kernel s= o I wouldn't be able to help you quickly. However, I might have a sugge= stion. Do you know if FreeBSD can be booted by U-Boot ? Because U-Boot defi= nitely 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 co= uld load FreeBSD from disk or network and start it. For instance as domU co= nfig file:

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

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 m= y knowledge. But I need to understand how to do it.

Well,let's say that on the ARM Chromebook I= 9;m forced to use and install a customized version of u-boot,created by vir= tual open systems,because it is the only one that allows bypassing its boot= loader protection. You can find more information here :

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

This is the relevant section to read :


Bootloader :

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


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


To be able to run KVM on ARM platforms, the ker= nel 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 booting methods would boot the kernel in the standard Supervi= sor mode. For the ARM Chromebook the default boot procedure doesn't all= ow 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 another= u-boot after the original). We can then enter hypervisor mode from our cus= tom 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$ cd u-boot$ ./scripts/b= uild.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 lat= er when preparing 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/sd= X1


so,the needed u-boot that we must use should be in= stalled 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 t= hat we created in the previous chapters,and use them to boot Chromebook wit= h a different kernel and OS. In all these examples the device /dev/sdX is u= sed. Take extra care to change the examples to the device that you have att= ached. Insert the boot medium on your workstation and carefully execute the= 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 partition= s in the medium, along with copying the u-boot binary to the first partitio= n:


Partition 1 =3D ChromeOS signed binary (V.O.S c= hained 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 fi= les


With u-boot being copied, next is the kernel im= age 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 f= ilesystem that we created earlier:


$ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./preci= se/* mnt/$ sudo umount /dev/sdX4


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


Partition 1 =3D ChromeOS signed binary (V.O.S chai= ned 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 (u= Image 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/configs/snow.h#L101


and it needs to be recompiled because it should po= int 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 workin= g 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 docum= ent ?

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://commo= ndatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow-si= mplefb.kpart.bz2

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

Maybe it can be found on this link :

http://lin= ux-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 Chro= mebook "SNOW" model XE303C12,that's powered by a Samsung Exyn= os 5250 (ARMv7 32 bit Cortex A15) Soc.


4) I'm not sure if I can chainload the customi= zed 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 t= he partition 2....


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


Code:=20 

CONFIG_CMO_BY_VA_ONLY=3Dy<=
/code>


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

--
Mario.


--
Mario.


--
Mario.


--
Mario.


--
Mario.


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Mario.
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