Re: How to boot FreeBSD for arm 32 bit as DomU with u-boot on my ARM Chromebook

From: Mario Marietto <marietto2008_at_gmail.com>
Date: Thu, 28 Dec 2023 16:25:30 UTC
Hello.

I'm trying to compile u-boot-2017.05 (because it can boot a 32-bit ARM
board. It is an out-of-tree u-boot build that can execute the ubldr to
boot FreeBSD. I found it here :

https://src.fedoraproject.org/repo/pkgs/uboot-tools/u-boot-2017.05.tar.bz2/sha512/be270f9242a72b05463092a022bbabd54996762de1ff23bf7575124ac02e62f49572a4e2f6f571a5019047d40027e56e35593b5cc373c4a5a39b100c3377ba93/

It has been suggested to me by the U-Boot Xen maintainers. Infact one
of them said :


Yes, it can boot a 32-bit ARM board. I'm not a FreeBSD person, but
I've helped a FreeBSD user booting a 32-bit ARM box with u-boot
(GoFlexHome Marvell Kirkwood 6281). The u-boot version was 2017.05.
I used an out-of-tree u-boot build. This u-boot executed the ubldr to
boot FreeBSD. Please see here :
https://forum.doozan.com/read.php?3,49039,82059#msg-82059


So. I tried to compile it directly on my ARM Chromebook,but it failed.
And it also fails if compiled with "ARCH=arm
CROSS_COMPILE=arm-linux-gnueabihf-" on my Ubuntu 23.04 x86_64
workstation :


/Chromebook/freebsd-xen/domU-freebsd/bootloaders/u-boot-2017.05# make
snow_defconfig

 HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
#
# configuration written to .config
#


/Chromebook/freebsd-xen/domU-freebsd/bootloaders/u-boot-2017.05# make

scripts/kconfig/conf  --silentoldconfig Kconfig
  CHK     include/config.h
  CFG     u-boot.cfg
  GEN     include/autoconf.mk
  GEN     include/autoconf.mk.dep
  CFG     spl/u-boot.cfg
  GEN     spl/include/autoconf.mk
  CHK     include/config/uboot.release
  CHK     include/generated/version_autogenerated.h
  UPD     include/generated/version_autogenerated.h
  CHK     include/generated/timestamp_autogenerated.h
  UPD     include/generated/timestamp_autogenerated.h
  CC      lib/asm-offsets.s
gcc: error: unrecognized -march target: armv5
gcc: note: valid arguments are: armv4 armv4t armv5t armv5te armv5tej
armv6 armv6j armv6k armv6z armv6kz armv6zk armv6t2 armv6-m armv6s-m
armv7 armv7-a armv7ve armv7-r armv7-m armv7e-m armv8-a armv8.1-a
armv8.2-a armv8.3-a armv8.4-a
armv8.5-a armv8.6-a armv8-m.base armv8-m.main armv8-r armv8.1-m.main
armv9-a iwmmxt iwmmxt2 native; did you mean ‘armv4’?
gcc: error: missing argument to ‘-march=’
make[1]: *** [Kbuild:44: lib/asm-offsets.s] Errore 1
make: *** [Makefile:1287: prepare0] Errore 2

What should I do to compile it succesfully ?

On Sat, Dec 23, 2023 at 7:36 PM Mario Marietto <marietto2008@gmail.com> wrote:
>
> I've added this parameter to bootxen.source :
>
> guest_loglvl=all
>
> bootxen.source :
>
> mmc dev 1
> ext2load mmc 1:3 0x42000000 zImage-5.4.261-iommu-dma-on-xen
> ext2load mmc 1:3 0x51000000 xen-4.17-armhf-armmp-0x51004000.ub
> ext2load mmc 1:3 0x5ffec000 exynos5250-snow.dtb
> fdt addr 0x5ffec000
> fdt resize 1024
> fdt set /chosen \#address-cells <0x2>
> fdt set /chosen \#size-cells <0x2>
> fdt set /chosen xen,xen-bootargs "console=dtuart dtuart=serial0 dom0_mem=1152M dom0_max_vcpus=2 bootscrub=0 vwfi=native guest_loglvl=all"
> fdt mknod /chosen dom0
> fdt set /chosen/dom0 compatible  "xen,linux-zimage" "xen,multiboot-module" "multiboot,module"
> fdt set /chosen/dom0 reg <0x0 0x42000000 0x0 0x49F9A8 >
> fdt set /chosen xen,dom0-bootargs "console=tty1 root=/dev/mmcblk1p4 rw rootwait clk_ignore_unused --no-log"
> bootm 0x51000000 - 0x5ffec000
>
>
> but when I try to boot FreeBSD I don't get more informations than usual :
>
> root@devuan-bunsen:/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen# ./start-freebsd
>
> Parsing config from freebsd.cfg
> xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader found: Invalid kernel
> libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image failed
> libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 1:cannot (re-)build domain: -3
> libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 1:Non-existent domain
> libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 1:Unable to destroy guest
> libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 1:Destruction of domain failed
> freebsd is an invalid domain identifier (rc=-6)
>
> Are you aware about a new parameter that I can use to have more detailed debug information ?
>
> On Wed, Dec 20, 2023 at 5:52 AM Warner Losh <imp@bsdimp.com> wrote:
>>
>> I'd think you'd need the right virtualization loader. I'm not entirely sure the u-boot.bin you've been creating is for a dom-u..
>> If I misunderstood, then the below isn't good advice. Chain booting the u-boot, the first u-boot initializes things so you want
>> to start with stage after the SPL. But the different error messages suggest that it's trying to reboot with kexec, which
>> isn't supported on armv7 at the moment.
>>
>> If you could boot in kvm, I think that the following would work....  Though I'm not entirely sure how to
>> specify the two .fd files in your setup. The use of qemu is to have an easy env to debug things... I don't
>> have a chromebook to try...
>>
>> My first instinct would be to try qemu on x86 (this is the first step of many to get to your destination).
>>
>> If you could boot the GENERIC_SD image that we produce using qemu + edk2-arm-code.fd that would
>> be a huge first step. This will give you the boot loader, I believe, to boot in the VM that you need better
>> than going via the u-boot route. Since you are booting in a virtualized environment, I think it wouldn't
>> matter which one :).
>>
>> So, I did the following to boot the virtualized armv7 FreeBSD environment, following a post on the forums I found and knew to have the right recipe:
>> https://forums.freebsd.org/threads/run-boot-freebsd-arm-32bit-image-in-qemu.80765/
>>
>> 1. pkg install qemu
>> 2. mkdir qemu-armv7-env
>> 3. cd qemu-armv7-env
>> 4. fetch https://download.freebsd.org/releases/arm/armv7/ISO-IMAGES/14.0/FreeBSD-14.0-RELEASE-arm-armv7-GENERICSD.img.xz
>> 5. xz -d -T 0 FreeBSD-14.0-RELEASE-arm-armv7-GENERICSD.img.xz
>> 6. dd if=/dev/zero of=pflash0.img bs=1m count=64
>> 7. dd if=/dev/zero of=pflash1.img bs=1m count=64
>> 8. dd if=/usr/local/share/qemu/edk2-arm-code.fd of=pflash0.img conv=notrunc
>> 9. dd if=/usr/local/share/qemu/edk2-arm-vars.fd of=pflash1.img conv=notrunc
>> 10. cat > start-freebsd-arm.sh
>> #!/bin/sh
>> qemu-system-arm \
>>   -M virt \
>>   -m 1024 \
>>   -drive file=pflash0.img,format=raw,if=pflash,readonly=on \
>>   -drive file=pflash1.img,format=raw,if=pflash \
>>   -drive file=$1.img,if=virtio,cache=writethrough \
>>   -nographic \
>>   -serial mon:stdio
>> ^D
>> 11. chmod +x start-freebsd-arm.sh
>> 12. ./start-freebsd-arm.sh FreeBSD-14.0-RELEASE-arm-armv7-GENERICSD
>>
>> But I hit a snag with this on qemu 8.1.2 and 8.1.3 with both 13.2 and 14.0:
>>
>> Starting devd.
>> Starting dhclient.
>> DHCPDISCOVER on vtnet0 to 255.255.255.255 port 67 interval 7
>> Fatal kernel mode data abort: 'Alignment Fault' on read
>> trapframe: 0xc4b36a60
>> FSR=00000001, FAR=dd96701a, spsr=20000013
>> r0 =00000000, r1 =00000001, r2 =00000001, r3 =c4b36b4c
>> r4 =00000014, r5 =d6618800, r6 =dd96702e, r7 =0000022c
>> r8 =00000000, r9 =0000022c, r10=dd96701a, r11=c4b36b90
>> r12=4300ffff, ssp=c4b36af0, slr=c04a9728, pc =c04a9750
>>
>> panic: Fatal abort
>> cpuid = 0
>> time = 1680843057
>> KDB: stack backtrace:
>> #0 0xc035786c at kdb_backtrace+0x48
>> #1 0xc02fdd20 at vpanic+0x140
>> #2 0xc02fdbe0 at vpanic+0
>> #3 0xc06304ac at abort_align+0
>> #4 0xc063052c at abort_align+0x80
>> #5 0xc063017c at abort_handler+0x480
>> #6 0xc060f480 at exception_exit+0
>> #7 0xc04a9750 at udp_input+0x288
>> #8 0xc0473f54 at ip_input+0x1e0
>> #9 0xc04447c0 at netisr_dispatch_src+0xf8
>> #10 0xc043bf2c at ether_demux+0x1a4
>> #11 0xc043d5e4 at ether_nh_input+0x480
>> #12 0xc04447c0 at netisr_dispatch_src+0xf8
>> #13 0xc043c404 at ether_input+0x50
>> #14 0xc01c0838 at vtnet_rx_vq_process+0x880
>> #15 0xc01b70d0 at vtpci_intx_intr+0xac
>> #16 0xc02b87f0 at ithread_loop+0x2ec
>> #17 0xc02b465c at fork_exit+0xc0
>> Uptime: 19s
>>
>> I don't know if this is a problem with qemu or FreeBSD's kernel...
>>
>> Warner
>>
>> On Tue, Dec 19, 2023 at 3:25 PM Mario Marietto <marietto2008@gmail.com> wrote:
>>>
>>> I've asked some help on the channel #arm on Reddit and someone replied :
>>>
>>> https://www.reddit.com/r/arm/comments/18mcir8/i_cant_boot_freebsd_for_arm32_bit_as_domu_with/
>>>
>>> Maybe his answer can be useful to understand why it does not work.
>>>
>>> On Tue, Dec 19, 2023 at 8:33 PM Stefano Stabellini <sstabellini@kernel.org> wrote:
>>>>
>>>> +Michal
>>>>
>>>> Hi Mario,
>>>>
>>>> I am not sure about booting FreeBSD, but I am certain that u-boot works
>>>> fine as DomU kernel on ARMv8 (not sure about ARMv7). With this config
>>>> file:
>>>>
>>>> name="test"
>>>> kernel="u-boot.bin"
>>>> extra = "console=hvc0"
>>>> memory=256
>>>> vcpus=1
>>>> disk = [ 'FreeBSD-13.2-RELEASE-armv7.img,raw,xvda' ]
>>>>
>>>> I don't know for sure if you can boot FreeBSD but you should definitely
>>>> be able to see the u-boot command line prompt. The fact that you are
>>>> getting this message:
>>>>
>>>> xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader found: Invalid kernel
>>>>
>>>> Means that something is not right in the u-boot configuration or u-boot
>>>> build. Michal and Artem (CCed) might know more. From what I recall,
>>>> there was nothing special required to get u-boot.bin to boot as domU
>>>> kernel, so now I wonder if it is an ARMv7 vs. ARMv8 issue.
>>>>
>>>> Cheers,
>>>>
>>>> Stefano
>>>>
>>>>
>>>> On Tue, 19 Dec 2023, Mario Marietto wrote:
>>>> > ....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 PM Mario Marietto <marietto2008@gmail.com> 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=arm CROSS_COMPILE=arm-linux-gnueabihf- make snow_defconfig : this line generates the file .config
>>>> > # nano .config and I've added these parameters :
>>>> >
>>>> > CONFIG_ARMV7_NONSEC=n
>>>> > CONFIG_EFI_GRUB_ARM32_WORKAROUND=y
>>>> >
>>>> > the uboot-bin file is generated with this command :
>>>> >
>>>> > # ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make
>>>> >
>>>> > At this point,I took a look inside the .config file and I saw that the parameter "CONFIG_ARMV7_NONSEC=n" 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="test"
>>>> > kernel="u-boot.bin"
>>>> > extra = "console=hvc0"
>>>> > memory=256
>>>> > vcpus=1
>>>> > disk = [ 'FreeBSD-13.2-RELEASE-armv7.img,raw,xvda' ]
>>>> >
>>>> > nano start-freebsd
>>>> >
>>>> > xl create freebsd.cfg
>>>> > xl console freebsd
>>>> >
>>>> > This is what happens when I launch the vm :
>>>> >
>>>> > # ./start-freebsd
>>>> >
>>>> > Parsing config from freebsd.cfg
>>>> > xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader found: Invalid kernel
>>>> > libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image failed
>>>> > libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 1:cannot (re-)build domain: -3
>>>> > libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 1:Non-existent domain
>>>> > libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 1:Unable to destroy guest
>>>> > libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 1:Destruction of domain failed
>>>> > freebsd is an invalid domain identifier (rc=-6)
>>>> >
>>>> >
>>>> > On Mon, Dec 18, 2023 at 12:39 PM Mario Marietto <marietto2008@gmail.com> 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 PM Mario Marietto <marietto2008@gmail.com> 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 should 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 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 :
>>>> >
>>>> > https://drive.google.com/file/d/1eAaZMfd6CU0xiqQfH7sq5wGVzzO09BRm/view?usp=sharing
>>>> >
>>>> > 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 as domU under Xen,as explained by Stefano Stabellini,the xen developer that suggested to me
>>>> > what I could do to have FreeBSD virtualized under Xen on my Arm Chromebook) ; otherwise the risk is to find later
>>>> > problems that will make me troubles and that I will not able to fix.
>>>> >
>>>> > I gave a look at the virtual open system u-boot and I didn't see any arndale_defconfig inside. So,If I have understood
>>>> > correctly,I should put that file inside the root of the u-boot source code,let's say here :
>>>> >
>>>> > marietto:/home/marietto/Desktop/Files/u-boot_FreeBSD/u-boot-vos # ls
>>>> >
>>>> > .checkpatch.conf        README                  doc                     net
>>>> > .git                    api                     drivers                 onenand_ipl
>>>> > .gitignore              arch                    dts                     post
>>>> > COPYING                 board                   examples                rules.mk
>>>> > CREDITS                 boards.cfg              fs                      scripts
>>>> > MAINTAINERS             common                  include                 snapshot.commit
>>>> > MAKEALL                 config.mk               lib                     spl
>>>> > Makefile                cros                    mkconfig                test
>>>> > PRESUBMIT.cfg           disk                    nand_spl                tools
>>>> >
>>>> > and I should do : make and make install ? and the file I need,u-boot.bin will be generated ?
>>>> >
>>>> > I didn't find any pre made configuration file inside :
>>>> >
>>>> > u-boot-vos # find . -type f -name "exynos*"
>>>> >
>>>> > ./include/exynos-fb.h
>>>> > ./include/configs/exynos5-common.h
>>>> > ./doc/device-tree-bindings/spi/exynos-spi.txt
>>>> > ./doc/device-tree-bindings/usb/exynos-usb.txt
>>>> > ./drivers/power/exynos-tmu.c
>>>> > ./drivers/power/exynos-cpufreq.c
>>>> > ./drivers/video/exynos-fb.c
>>>> > ./drivers/spi/exynos_spi.c
>>>> > ./board/samsung/dts/exynos5250-spring.dts
>>>> > ./board/samsung/dts/exynos5250-smdk5250.dts
>>>> > ./board/samsung/dts/exynos5250-snow.dts
>>>> > ./board/samsung/dts/exynos5250-daisy.dts
>>>> > ./arch/arm/include/asm/arch-exynos5/exynos-cpufreq.h
>>>> > ./arch/arm/include/asm/arch-exynos5/exynos-tmu.h
>>>> > ./arch/arm/dts/exynos5250.dtsi
>>>> > ./arch/arm/dts/exynos-periph-id.dtsi
>>>> > ./arch/arm/cpu/armv7/exynos5/exynos_cache.c
>>>> >
>>>> > u-boot-vos # find . -type f -name "arndale*"
>>>> >
>>>> > For sure I can't use a newer version of u-boot because otherwise the patches needed to bypass the bootloader protections
>>>> > of the Arm 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 these two options, compiling u-boot for
>>>> > FreeBSD: https://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=n
>>>> > CONFIG_EFI_GRUB_ARM32_WORKAROUND=y
>>>> >
>>>> > These are the parameters used to configure a Linux kernel. I don't understand what's the relation between the compilation
>>>> > of a linux kernel and u-boot. In the past I tried to recompile u-boot,but I didn't have 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't understand what you mean under "the first u-boot".
>>>> >
>>>> >
>>>> > I'm talking about first u-boot because the whole procedure to boot Linux on the ARM Chromebook,that's explained here :
>>>> >
>>>> > http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/
>>>> >
>>>> >
>>>> > at some point they say :
>>>> >
>>>> >
>>>> > To be able to run KVM on ARM platforms, the kernel has to be booted in hypervisor mode. Because of this relatively recent
>>>> > requirement (due to the introduction of the virtualization extensions), up until now all booting methods would boot the
>>>> > kernel in the standard Supervisor mode.
>>>> >
>>>> > For the ARM Chromebook the default boot procedure doesn't allow us to boot in hypervisor mode. Although the laptop's boot
>>>> > mechanism is based 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
>>>> > 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 don't need it if we want to boot Linux with kvm or xen
>>>> > enabled.
>>>> >
>>>> >
>>>> > On Sun, Dec 17, 2023 at 1:28 AM 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=en
>>>> >
>>>> > 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-Architecture/The-System-Level-Programmers--Model/The-Virtualization-Extens
>>>> > ions), 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, 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, 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 happen 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-open-system 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 AM 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=heads#L3
>>>> >
>>>> > As for compiling the u-boot, it is a doable task, given that you understand what you are doing. There
>>>> > are no specific options in u-boot devoted to FreeBSD. It is a boot loader, whose mission to make basic
>>>> > hardware initialization, read you kernel file from some media into RAM and then pass it control.
>>>> >
>>>> > Basically, you can grab some defconfig, prepared for any other Exynos5250 based board  (say, this one:
>>>> > https://source.denx.de/u-boot/u-boot/-/blob/master/configs/arndale_defconfig?ref_type=heads) 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-master/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 specific file that's on the source code of FreeBSD :
>>>> >
>>>> >
>>>> >       https://xenbits.xen.org/gitweb/?p=p...8;hb=0782e25d98cc1391472717035f986c979edef0c9
>>>> >
>>>> >
>>>> >       This patch was written by Julien Grall a lot of time ago and now it does not work anymore.
>>>> >       This is the reason :
>>>> >
>>>> >
>>>> >             It appears FreeBSD-CURRENT removed the last step converting the kernel file to
>>>> >             kernel.bin. The patch can be readily rebased, but without kernel.bin that
>>>> >             doesn't do too much
>>>> >
>>>> >
>>>> >
>>>> > So,without a rebase of that patch the first option is not applicable. And I'm not able to fix it.
>>>> >
>>>> > 2) booting FreeBSD using U-Boot,as explained to me by a xen developer :
>>>> >
>>>> >
>>>> >       I was trying to explain why and how Julien's patch works so that you could be the one
>>>> >       to re-do something similar or fix the patch on the FreeBSD kernel that you are
>>>> >       working with. I am happy to help review and write patches but I don't work with the
>>>> >       FreeBSD kernel so I wouldn't be able to help you quickly. However, I might have a
>>>> >       suggestion. Do you know if FreeBSD can be booted by U-Boot ? Because U-Boot
>>>> >       definitely boots as 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="/home/petalinux/u-boot.bin"
>>>> >       disk = [ '/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=y
>>>> >
>>>> >
>>>> >
>>>> > 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
>>>> > bootloader protection. You can find more information here :
>>>> >
>>>> > http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/?vos=tech
>>>> >
>>>> > 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 (due to the introduction of the
>>>> >       virtualization extensions), up until now all booting methods would boot the kernel in
>>>> >       the standard Supervisor mode. For the ARM Chromebook the default boot procedure
>>>> >       doesn't allow us to boot in hypervisor mode. Although the laptop's boot mechanism is
>>>> >       based 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 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$ cd u-boot$
>>>> >       ./scripts/build.sh
>>>> >
>>>> >
>>>> >       If successful, a message about how to copy the bootloader on the USB flash disk or SD
>>>> >       card will appear. We will use it later when preparing the boot medium to start our
>>>> >       system. If you have followed the Setting up the boot medium chapter and you have a
>>>> >       prepared boot device, then you can update u-boot by running :
>>>> >
>>>> >
>>>> >       $ sudo dd if=nv_uboot-snow.kpart of=/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 kernel 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 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, along with copying
>>>> >       the u-boot binary to the first partition:
>>>> >
>>>> >
>>>> >       Partition 1 = ChromeOS signed binary (V.O.S chained u-boot)
>>>> >       Partition 2 = not used
>>>> >       Partition 3 = EXT2 partition for u-boot files (uImage and exynos5250-snow.dtb)
>>>> >       Partition 4 = EXT4 partition for userspace files
>>>> >
>>>> >
>>>> >       With u-boot being copied, next is the kernel image and DTB file. From the kernel
>>>> >       source execute :
>>>> >
>>>> >
>>>> >       $ mkdir ../mnt/
>>>> >       $ sudo mount /dev/sdX3 ../mnt/
>>>> >       $ sudo cp arch/arm/boot/uImage ../mnt/
>>>> >       $ sudo cp arch/arm/boot/dts/exynos5250-snow.dtb ../mnt/
>>>> >       $ sudo umount /dev/sdX3
>>>> >
>>>> >
>>>> >       Finally, we have to copy the Ubuntu userspace filesystem that we created earlier:
>>>> >
>>>> >
>>>> >       $ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./precise/* mnt/$ sudo umount /dev/sdX4
>>>> >
>>>> >
>>>> >
>>>> > Now,my idea is to chainload the already chain loaded u-boot created by V.O.S to the new u-boot
>>>> > that we need for booting FreeBSD and that can be installed in the partition n.2,as shown in this
>>>> > scheme,because it is not used :
>>>> >
>>>> >
>>>> > Partition 1 = ChromeOS signed binary (V.O.S chained u-boot)
>>>> > Partition 2 = not used (maybe we can install the u-boot for arm 32 bit,compatible with FreeBSD on
>>>> > this partition)
>>>> > Partition 3 = EXT2 partition for u-boot files (uImage and exynos5250-snow.dtb)
>>>> > Partition 4 = 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 point to the partition n.2,where I will install
>>>> > the u-boot files as explained here :
>>>> >
>>>> >
>>>> > https://wiki.freebsd.org/arm/Chromebook
>>>> >
>>>> >
>>>> > I have some questions to ask before I start working on this.
>>>> >
>>>> > 1) The xen developer said :
>>>> >
>>>> >
>>>> >       You should be able to build U-Boot and use the U-Boot binary as Xen guest kernel...
>>>> >
>>>> >
>>>> >
>>>> > where is the u-boot binary,according to this document ?
>>>> >
>>>> > https://wiki.freebsd.org/arm/Chromebook
>>>> >
>>>> > I don't see it.
>>>> >
>>>> >
>>>> > 2) where is the source code of the file that I can get here :
>>>> >
>>>> > http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow-simplefb.kpart.bz2
>>>> >
>>>> > I need the source code if I want to recompile u-boot so that it can point to the partition 4.
>>>> >
>>>> > Maybe it can be found on this link :
>>>> >
>>>> > http://linux-exynos.org/dist/chromebook/nv_uboot/
>>>> >
>>>> > but it can't be opened....
>>>> >
>>>> >
>>>> > 3) in this specific scenario the source code of u-boot should run on arm 32 bit,not on arm
>>>> > 64,because I have the Samsung Chromebook "SNOW" model XE303C12,that's powered by a Samsung Exynos
>>>> > 5250 (ARMv7 32 bit Cortex A15) Soc.
>>>> >
>>>> >
>>>> > 4) I'm not sure if I can chainload the customized u-boot created by V.O.S that should be
>>>> > installed on the first partition with the u-boot tailored for booting FreeBSD that should be
>>>> > installed on the partition 2....
>>>> >
>>>> >
>>>> > 5) the xen developer said that u-boot should be compiled enabling this option :
>>>> >
>>>> >
>>>> > Code:
>>>> >
>>>> > CONFIG_CMO_BY_VA_ONLY=y
>>>> >
>>>> >
>>>> > 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.
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > Mario.
>>>> >
>>>> >
>>>
>>>
>>>
>>> --
>>> Mario.
>
>
>
> --
> Mario.



--
Mario.