Date: Sun, 17 Dec 2023 00:56:41 +0100 From: Mario Marietto <marietto2008@gmail.com> To: Stanislav Silnicki <stanislav.silnicki@mailgate.us> Cc: freebsd-arm@freebsd.org Subject: Re: How to boot FreeBSD for arm 32 bit as DomU with u-boot on my ARM Chromebook Message-ID: <CA%2B1FSiheSwrO7Tz3F3Nmu4vcC2E=ONRX8nF3bhQGV0UDOFTrww@mail.gmail.com> In-Reply-To: <97aa980b9b44.6eb7f9d5c54e7@mailgate.us> References: <CA%2B1FSiit5NJ_W7f5mssivkGGLevXh_XmSB7ZxZbQe1dgev0_Pg@mail.gmail.com> <97aa980b9b44.6eb7f9d5c54e7@mailgate.us>
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--000000000000daf264060ca946b2 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ---> 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=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/Kco= nfig?ref_type=3Dheads#L3 > > As for compiling the u-boot, it is a doable task, given that you > understand what you are doing. There are no specific options in u-boot > devoted to FreeBSD. It is a boot loader, whose mission to make basic > hardware initialization, read you kernel file from some media into RAM an= d > 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_defcon= fig?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-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=3Dp...8;hb=3D0782e25d98cc1391472717035f= 986c979edef0c9 > <https://xenbits.xen.org/gitweb/?p=3Dpeople/julieng/freebsd.git;a=3Dblob_= plain;f=3Dsys/arm/conf/XENVIRT;h=3Dff6433392e6fc2d5fa7c1ad1f7c40155003af9a8= ;hb=3D0782e25d98cc1391472717035f986c979edef0c9> > > > 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 coul= d > 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 fro= m > 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 i= s > the only one that allows bypassing its bootloader protection. You can fin= d > 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 download a pre-compiled binary o= f > 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 th= e > introduction of the virtualization extensions), up until now all booting > methods would boot the kernel in the standard Supervisor mode. For the AR= M > 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 iteratio= n > 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 flas= h > 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=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 kernel > and OS. In all these examples the device /dev/sdX is used. Take extra car= e > 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 wit= h > copying the u-boot binary to the first partition: > > > Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot) > Partition 2 =3D not used > Partition 3 =3D EXT2 partition for u-boot files (uImage and > exynos5250-snow.dtb) > Partition 4 =3D EXT4 partition for userspace files > > > With u-boot being copied, next is the kernel image and DTB file. From the > kernel source execute : > > > $ mkdir ../mnt/ > $ sudo mount /dev/sdX3 ../mnt/ > $ sudo cp arch/arm/boot/uImage ../mnt/ > $ sudo cp arch/arm/boot/dts/exynos5250-snow.dtb ../mnt/ > $ sudo umount /dev/sdX3 > > > Finally, we have to copy the Ubuntu userspace filesystem that we created > earlier: > > > $ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./precise/* mnt/$ sudo umount > /dev/sdX4 > > > > Now,my idea is to chainload the already chain loaded u-boot created by > V.O.S to the new u-boot that we need for booting FreeBSD and that can be > installed in the partition n.2,as shown in this scheme,because it is 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/configs/s= now.h#L101 > <https://github.com/virtualopensystems/u-boot/blob/eecfeb578e296ef3b739ac= 918a39b6c177dff58a/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=3Dy > > > > Well,can you provide some good source that can help me to understand how = I > can recompile u-boot for FreeBSD ? thanks. > > -- > Mario. > > --=20 Mario. --000000000000daf264060ca946b2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div>---> 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.</div= ><div><br></div><div>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'. </d= iv><div><br></div><div><br></div></div><br><div class=3D"gmail_quote"><div = dir=3D"ltr" class=3D"gmail_attr">On Sun, Dec 17, 2023 at 12:35=E2=80=AFAM S= tanislav Silnicki <<a href=3D"mailto:stanislav.silnicki@mailgate.us">sta= nislav.silnicki@mailgate.us</a>> wrote:<br></div><blockquote class=3D"gm= ail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,= 204,204);padding-left:1ex"><div><div>=20 =20 =20 =20 =20 =20 =20 <div> =20 =20 =20 =20 =20 =20 =20 <div id=3D"m_5085590471051268986compose-body-wrapper" dir=3D"auto"= ><div dir=3D"auto">Hi=20 Mario,</div><div dir=3D"auto"><br></div><div dir=3D"auto">U-Boot=C2=A0 beas= t is=20 hiding in this den: <a href=3D"https://source.denx.de/u-boot/u-boot.git" ta= rget=3D"_blank">https://source.denx.de/u-boot/u-boot.git</a></div><div dir= =3D"auto">I took a brief look at your post and it seems to me, that=20 option=C2=A0<span style=3D"font-family:SFMono-Regular,Menlo,Monaco,Consolas= ,"Liberation Mono","Courier New",monospace;font-size:in= herit">CONFIG_CMO_BY_VA_ONLY</span>=C2=A0is irrelevant to=20 your target armv7 32 bit=20 platform:=C2=A0<a href=3D"https://source.denx.de/u-boot/u-boot/-/blob/maste= r/arch/arm/cpu/armv8/Kconfig?ref_type=3Dheads#L3" target=3D"_blank">https:/= /source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/cpu/armv8/Kconfig?ref_= type=3Dheads#L3</a></div><div dir=3D"auto" id=3D"m_5085590471051268986tmjah= _g_1299"><br></div><div dir=3D"auto" id=3D"m_5085590471051268986tmjah_g_129= 9">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. </div><div dir=3D"auto" id=3D"m_5085590471051268986tmjah_g_1299= "><br></div><div dir=3D"auto" id=3D"m_5085590471051268986tmjah_g_1299">Basi= cally, you can grab some defconfig,=20 prepared for any other Exynos5250 based board=C2=A0 (say, this one: <a href= =3D"https://source.denx.de/u-boot/u-boot/-/blob/master/configs/arndale_defc= onfig?ref_type=3Dheads)" target=3D"_blank">https://source.denx.de/u-boot/u-= boot/-/blob/master/configs/arndale_defconfig?ref_type=3Dheads)</a>=20 and adopt it somehow.</div><div dir=3D"auto" id=3D"m_5085590471051268986tmj= ah_g_1299"><br></div><div dir=3D"auto" id=3D"m_5085590471051268986tmjah_g_1= 299">As per my experience, you have to respect=20 these two options, compiling u-boot for FreeBSD:=C2=A0<a href=3D"https://gi= thub.com/freebsd/freebsd-ports/blob/main/sysutils/u-boot-master/files/FreeB= SD_Fragment" target=3D"_blank">https://github.com/freebsd/freebsd-ports/blo= b/main/sysutils/u-boot-master/files/FreeBSD_Fragment</a></div><div dir=3D"a= uto" id=3D"m_5085590471051268986tmjah_g_1299"><br></div><div dir=3D"auto" i= d=3D"m_5085590471051268986tmjah_g_1299">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.</div><div dir=3D"auto"= id=3D"m_5085590471051268986tmjah_g_1299"><br></div><div dir=3D"auto" id=3D= "m_5085590471051268986tmjah_g_1299">Hope, this=20 will help to progress you tasks</div><div dir=3D"auto" id=3D"m_508559047105= 1268986tmjah_g_1299">Stan</div><div dir=3D"auto" id=3D"m_508559047105126898= 6tmjah_g_1299"><br></div></div><div dir=3D"auto">Mario=20 Marietto wrote:</div><br><br><div><blockquote type=3D"cite" style=3D"margin= :0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"= ><div dir=3D"ltr"><div><div><div><div id=3D"m_5085590471051268986gmail-:1fg= "><div id=3D"m_5085590471051268986gmail-:1ay"><div dir=3D"ltr">Hello.<br> <br> 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 :<br> <br> 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 :<br> <br> <br> <a href=3D"https://xenbits.xen.org/gitweb/?p=3Dpeople/julieng/freebsd.git;a= =3Dblob_plain;f=3Dsys/arm/conf/XENVIRT;h=3Dff6433392e6fc2d5fa7c1ad1f7c40155= 003af9a8;hb=3D0782e25d98cc1391472717035f986c979edef0c9" rel=3D"nofollow ugc= noopener" target=3D"_blank">https://xenbits.xen.org/gitweb/?p=3Dp...8;hb= =3D0782e25d98cc1391472717035f986c979edef0c9</a><br> <br> <br> This patch was written by Julien Grall a lot of time ago and now it does=20 not work anymore. This is the reason :<br> <br> <br> <blockquote> =09 <div> =09 <div> 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. </div> =09 </div> </blockquote><br> <br> So,without a rebase of that patch the first option is not applicable. And= =20 I'm not able to fix it.<br> <br> 2) booting FreeBSD using U-Boot,as explained to me by a xen developer :<br> <br> <br> <blockquote> =09 <div> =09 <div> 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:<br> <br> kernel=3D"/home/petalinux/u-boot.bin"<br> disk =3D [ '/home/petalinux/test.img,raw,xvda' ]<br> <br> I know it is important to build u-boot with the following config to make it= =20 work on Xen.<br> <br> CONFIG_CMO_BY_VA_ONLY=3Dy </div> =09 </div> </blockquote><br> <br> This option seems more doable to me according to my knowledge. But I need= =20 to understand how to do it.<br> <br> 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 :<br> <br> <a href=3D"http://www.virtualopensystems.com/en/solutions/guides/kvm-on-chr= omebook/?vos=3Dtech" rel=3D"nofollow ugc noopener" target=3D"_blank">http:/= /www.virtualopensystems.com/en/solutions/guides/kvm-on-chromebook/?vos=3Dte= ch</a><br> <br> This is the relevant section to read :<br> <br> <br> <blockquote> =09 <div> =09 <div> Bootloader :<br> <br> If you wish to skip this chapter you can download a pre-compiled binary of= =20 the bootloader:<br> <br> <br> $ wget <a href=3D"http://www.virtualopensystems.com/downloads/guides/kvm_on= _chromebook/nv_u-boot-snow.kpart" rel=3D"nofollow ugc noopener" target=3D"_= blank">http://www.virtualopensystems.com/downloads/guides/kvm_on_chromebook= /nv_u-boot-snow.kpart</a><br> <br> <br> 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.<br> <br> Checkout the needed u-boot code :<br> <br> <br> $ git clone git://<a href=3D"http://github.com/virtualopensystems/u-boot.gi= t$" rel=3D"nofollow ugc=20 noopener" target=3D"_blank">github.com/virtualopensystems/u-boot.git$</a> c= d=20 u-boot$ ./scripts/build.sh<br> <br> <br> 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 :<br> <br> <br> $ sudo dd if=3Dnv_uboot-snow.kpart of=3D/dev/sdX1 </div> =09 </div> </blockquote><br> <br> so,the needed u-boot that we must use should be installed on the first=20 partition of the sd card.<br> <br> There is another relevant section to read :<br> <br> <br> <blockquote> =09 <div> =09 <div> Setting up the boot medium<br> <br> 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.<br> <br> In the uboot source directory :<br> <br> <br> $ sudo ./scripts/sdcard.sh /dev/sdX<br> <br> <br> This will erase all data and create 4 partitions in the medium, along with= =20 copying the u-boot binary to the first partition:<br> <br> <br> Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot)<br> Partition 2 =3D not used<br> Partition 3 =3D EXT2 partition for u-boot files (uImage and=20 exynos5250-snow.dtb)<br> Partition 4 =3D EXT4 partition for userspace files<br> <br> <br> With u-boot being copied, next is the kernel image and DTB file. From the= =20 kernel source execute :<br> <br> <br> $ mkdir ../mnt/<br> $ sudo mount /dev/sdX3 ../mnt/<br> $ sudo cp arch/arm/boot/uImage ../mnt/<br> $ sudo cp arch/arm/boot/dts/exynos5250-snow.dtb ../mnt/<br> $ sudo umount /dev/sdX3<br> <br> <br> Finally, we have to copy the Ubuntu userspace filesystem that we created=20 earlier:<br> <br> <br> $ sudo mount /dev/sdX4 mnt/$ sudo cp -a ./precise/* mnt/$ sudo umount=20 /dev/sdX4 </div> =09 </div> </blockquote><br> <br> 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 :<br> <br> <br> Partition 1 =3D ChromeOS signed binary (V.O.S chained u-boot)<br> Partition 2 =3D not used (maybe we can install the u-boot for arm 32=20 bit,compatible with FreeBSD on this partition)<br> Partition 3 =3D EXT2 partition for u-boot files (uImage and=20 exynos5250-snow.dtb)<br> Partition 4 =3D EXT4 partition for userspace files<br> <br> <br> Take in consideration that default boot string is hardcoded here,in the=20 snow.h file of the custom u-boot created by VOS :<br> <br> <br> <a href=3D"https://github.com/virtualopensystems/u-boot/blob/eecfeb578e296e= f3b739ac918a39b6c177dff58a/include/configs/snow.h#L101" rel=3D"nofollow ugc= noopener" target=3D"_blank">https://github.com/virtualopensyste...18a39b6c= 177dff58a/include/configs/snow.h#L101</a><br> <br> <br> 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 :<br> <br> <br> <a href=3D"https://wiki.freebsd.org/arm/Chromebook" rel=3D"nofollow ugc=20 noopener" target=3D"_blank">https://wiki.freebsd.org/arm/Chromebook</a><br>; <br> <br> I have some questions to ask before I start working on this.<br> <br> 1) The xen developer said :<br> <br> <br> <blockquote> =09 <div> =09 <div> You should be able to build U-Boot and use the U-Boot binary as Xen=20 guest kernel... </div> =09 </div> </blockquote><br> <br> where is the u-boot binary,according to this document ?<br> <br> <a href=3D"https://wiki.freebsd.org/arm/Chromebook" rel=3D"nofollow ugc=20 noopener" target=3D"_blank">https://wiki.freebsd.org/arm/Chromebook</a><br>; <br> I don't see it.<br> <br> <br> 2) where is the source code of the file that I can get here :<br> <br> <a rel=3D"nofollow ugc=20 noopener">http://commondatastorage.googleapis.com/chromeos-localmirror/dist= files/nv_uboot-snow-simplefb.kpart.bz2</a><br> <br> I need the source code if I want to recompile u-boot so that it can point= =20 to the partition 4.<br> <br> Maybe it can be found on this link :<br> <br> <a href=3D"http://linux-exynos.org/dist/chromebook/nv_uboot/" rel=3D"nofoll= ow=20 ugc noopener" target=3D"_blank">http://linux-exynos.org/dist/chromebook/nv_= uboot/</a><br> <br> but it can't be opened....<br> <br> <br> 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.<br> <br> <br> 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....<br> <br> <br> 5) the xen developer said that u-boot should be compiled enabling this=20 option :<br> <br> <br> =09 =09 <div> <div> Code: <br></div><div><br></div> <div dir=3D"ltr"> <pre dir=3D"ltr"><code>CONFIG_CMO_BY_VA_ONLY=3Dy</code></pre> </div> </div><br> <br> 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></div></div></div></div></div><div><div><div><div id=3D"m_5085= 590471051268986gmail-:1fh"><table role=3D"presentation"><tbody><tr><td><br>= </td><td></td></tr></tbody></table></div></div></div></div><span class=3D"g= mail_signature_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_signat= ure">Mario.<br></div></div></blockquote></div> =20 =20 =20 </div> =20 =20 </div></div></blockquote></div><br clear=3D"all"><br><span class=3D"gmai= l_signature_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_signature= ">Mario.<br></div> --000000000000daf264060ca946b2--
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