Compilation for Chrome OS devices

[JLIT0]

Would it be possible to make a compilation target for ARM-based Chromebooks running the included Linux runtime?

[ptitSeb]

Yes, sure. What would be the CFLAGS parameters tu use (and LDFLAGS also maybe?)

[JLIT0]

About half of the Chrome OS ARM devices are using the Rockchip RK3399, which has the following cflags:

CFLAGS="--target=aarch64-unknown-linux-gnu -O3 -pipe -march=armv8-a+crc+simd+crypto -mcpu=cortex-a72+crc+simd+crypto"

Roughly the other half uses the MediaTek MT8173C, which I don't know the cflags for.

[ptitSeb]

ok, but don't forget box86 is a 32bits apps, and need a 32bits chroot/multiarch/whetever to run on aarch64 linux. That may change at least the --target no?

[JLIT0]

Yep, so we can substitute aarch64 for armhf

I've just quickly tested, and the Crostini runtime does allow you to add the armhf architecture and run packages within 64-bit Chrome OS on an RK3399, so it shouldn't be an issue.

[ptitSeb]

I have added support for RK3399 in the CMakeList now. Does the support is enough for this ticket to be closed?

[Maccraft123]

ChromeOS laptops have regular ARM CPUs that shouldn't be under one "chromeos" device I think it'd be a better idea to just add RK3288, RK3399, MT8183 options. There isn't really anything special in ARM chromebooks to not have them under same umbrella as "regular" ARM SBCs

[kaosushijin]

I'm failing to build with the MT8183. The RK3399 build appears to succeed, but the resulting binary is non-operable.

[ptitSeb]

MT8183 seems to be Cortex-A73/-A53. How the RK3399 is non-operable? What kind of error do you get?

[kaosushijin]

jinx@penguin:~/box86/build$ sudo make install
Consolidate compiler generated dependencies of target dynarec_arm
[  3%] Built target dynarec_arm
[  3%] Built target WRAPPERS
Consolidate compiler generated dependencies of target arm_pass0
[ 11%] Built target arm_pass0
Consolidate compiler generated dependencies of target arm_pass1
[ 19%] Built target arm_pass1
Consolidate compiler generated dependencies of target arm_pass2
[ 27%] Built target arm_pass2
Consolidate compiler generated dependencies of target arm_pass3
[ 35%] Built target arm_pass3
[ 36%] Built target dynarec
[ 36%] Built target PRINTER
Consolidate compiler generated dependencies of target box86
[100%] Built target box86
Install the project...
-- Install configuration: "RelWithDebInfo"
-- Installing: /usr/local/bin/box86
-- Installing: /etc/binfmt.d/box86.conf
-- Installing: /usr/lib/i386-linux-gnu/libstdc++.so.6
-- Installing: /usr/lib/i386-linux-gnu/libstdc++.so.5
-- Installing: /usr/lib/i386-linux-gnu/libgcc_s.so.1
jinx@penguin:~/box86/build$ cd
jinx@penguin:~$ sudo systemctl restart systemd-binfmt
Job for systemd-binfmt.service failed because the control process exited with error code.
See "systemctl status systemd-binfmt.service" and "journalctl -xeu systemd-binfmt.service" for details.
jinx@penguin:~$ box86 -v
-bash: /usr/local/bin/box86: No such file or directory
jinx@penguin:~$ box86 --help
-bash: /usr/local/bin/box86: No such file or directory
jinx@penguin:~$ 

[ptitSeb]

Ah ok. You are missing the "armhf" multiarch. If you are on debian/armbian/ubuntu, use "sudo dpk --add-architeture armhf && sudo apt update && sudo apt install libc6:armhf" at least to have box86 running. On other OS, you need to use chroot or something similar...

[kaosushijin]

Success! Something about the compile instructions gave me the impression that multiarch wouldn't be necessary. Now to fiddle with i386 wine to see if I can get Avernum going. It would be a huge add to this Chromebook. Thanks!

[ptitSeb]

Good :)

You will need a few more armhf libs for wine, like x11 and many other. Unfortunatly, I don't have the list.

[nhobson99]

I followed similar instructions to build, but used the Snapdragon 845 target since my Chromebook uses a Snapdragon 7C (which I assume is close enough, it's all ARM64). I did indeed have to enable the armhf architecture.

However, for some reason it doesn't seem to have proper binfmt support.

pirouette@penguin:~/box86/build$ sudo update-binfmts --display
box86.conf (disabled):
     package = box86
        type = magic
      offset = 0
       magic = \x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff
        mask = 
 interpreter = /usr/local/bin/box86
    detector = 
python3.10 (enabled):
     package = python3.10
        type = magic
      offset = 0
       magic = \x6f\x0d\x0d\x0a
        mask = 
 interpreter = /usr/bin/python3.10
    detector = 

This is after manually copying the box86.conf file into /usr/share/binfmts/box86.conf as per #419 , accounting for the differing format since I'm using a Ubuntu 22.04 container on Chrome OS (the default container they give you is Debian Bullseye).

I also had to manually enable mounting namespaces in Chrome OS, which I had to search for as well. OP can be found here, but the necessary component is:

1. vmc start termina
2. From a separate shell-  vmc container termina giraffe --privileged true

Now, if I try to enable binfmt support, I'm shown the following:

pirouette@penguin:~/box86/build$ sudo update-binfmts --enable
update-binfmts: warning: unable to close /proc/sys/fs/binfmt_misc/register: Invalid argument
update-binfmts: exiting due to previous errors

Unfortunately I'm stuck here. Without binfmt support, anything that fork/execs doesn't want to work. Is there something I'm missing?

[nhobson99]

I was able to partially fix this issue by doing a few additional things:

From Crosh

• Enter termina (vmc launch termina)
• Inside termina:
  • lxc config set security.nesting true
  • lxc config set security.virtualization true
• Exit termina, reboot Chrome OS

After modifying lxc configs, it takes a little longer for the virtual machine to start up. Wait a few minutes to finish updating (it should give you a notification that the virtual machine is being updated), then launch Terminal as usual.

Now, back in Terminal, update /usr/share/binfmts/box86.conf to read as follows:

package box86
interpreter /usr/local/bin/box86
magic \x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00
mask \xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff

Then sudo update-binfmts --import box86.conf and sudo update-binfmts --enable should just work. Finally after all that work, I receive the following:

pirouette@penguin:~$ sudo update-binfmts --display
box86.conf (enabled):
     package = box86
        type = magic
      offset = 0
       magic = \x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00
        mask = \xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff
 interpreter = /usr/local/bin/box86
    detector = 

However, trying to actually run anything just results in box86 not working. Example:

pirouette@penguin:~$ sudo apt install hello:i386
pirouette@penguin:~$ hello
-bash: /usr/bin/hello: No such file or directory

Trying to run Box86 without binfmt does not seem to work either:

pirouette@penguin:~$ box86 /usr/bin/hello 
-bash: /usr/local/bin/box86: No such file or directory

I'll keep digging through GitHub and Chrome OS issues to see if I can find anything, but I'm definitely running out of ideas.

...

Additional (important) information: I gave up on Ubuntu 22.04 for the sole reason that it doesn't natively support side-by-side multiarch, meaning I couldn't install libc6:i386 alongside libc6:arm64. I'm now running a custom container with Debian Bookworm (arm64) installed, which is basically just a more up to date version of the default Bullseye container that Terminal sets up by default. If you want to follow along with Ubuntu, you'll need a chroot or proot setup. I'm no expert at that, but there are guides that are relatively easy to follow. You'll still need nesting and virtualization enabled for this to work, as far as I can tell.

(For those curious, I wanted a variable sized virtual machine, so I had to build the container myself anyway, and I figured I might as well update to Bookworm while I was at it.)

[nhobson99]

Ok, partial success after looking at #465 . I completely forgot to install the armhf version of libc6, which as I understand is the interpreter responsible for loading and running 32 bit arm executables (even on arm64).

I feel very close now to getting this fully working on Crostini. I can run simple text based programs now, still yet to run graphical programs. I'm surely only missing one small piece of the puzzle now.

Sorry for the... triple post at this point, but I think documenting my experience is worthwhile, and I can make a full writeup when I'm successful in my end goal of launching Steam.