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I wonder if WSL will support the i386 (32 bit) program running later? #2468

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@erikaemma

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@erikaemma

I just want to run arm-linux-gcc 4.4.3 :}

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get dist-upgrade

sudo apt-get install g++-multilib
sudo apt-get install libncurses5:i386
sudo apt-get install libc6:i386 libgcc1:i386 gcc-4.8-base:i386 libstdc++5:i386 libstdc++6:i386
sudo apt-get install lib32z1 lib32ncurses5 lib32ncursesw5 lib32ncursesw5-dev 

Activity

therealkenc

therealkenc commented on Sep 3, 2017

@therealkenc

The User Voice was opened back up. If the embedded people were as organised as university students taking Machine Learning courses it would have a better chance.

poizan42

poizan42 commented on Sep 4, 2017

@poizan42

@plgkm6 That is quite an old gcc, do you need it for binary compatibility? Can't you just use 4.4.7? It is my understanding that gcc never breaks binary compatibility in minor releases. I believe you can just install the amd64 versions of the cross compiler from an older ubuntu version - you can find the softfloat version here and hardfloat version here. Select the amd64 built, you'll need the gcc-..._base_..., cpp-... and gcc-... packages at least.

For c++ support you will also need the g++-... and libstdc++6-4.4-dev-... packages.

If you really need gcc 4.4.3 then you could build a version for a 64-bit host yourself, there are plenty of guides on how to build gcc cross compilers.

therealkenc

therealkenc commented on Sep 4, 2017

@therealkenc

I was going to mention using the amd64 cross; but didn't because it isn't the root of (some of) the embedded guys' difficulty. The problem is many of their platform's supported build toolchains are stuck on 32-bit. Most notably Android, but also other embedded scenarios. Ref #1687, #1771, et al

MikeGitb

MikeGitb commented on Sep 6, 2017

@MikeGitb

Disclaimer: I'm a x64 zealot and I'm programming embedded systems down to 8bit microcontroller, but have almost no experience with Android development.

My hope would be that without 32 support, the tool vendors get more pressure to update their toolchains and I'd much rather see some progress on their side than resources being wasted on backwards compatibility on the WSL side.

therealkenc

therealkenc commented on Sep 6, 2017

@therealkenc

I'm a x64 zealot

Yeah, me too a little. That said, you'd think Microsoft would be more sympathetic. My Visual Studio 2017 (August preview) is 32-bit, almost 15 years after Opteron was released. If the implication here is that Microsoft should encourage tool vendors like say Google to update, an obvious retort would be: "Whatever dude. You first."

Funny story if you are a 64-bit zealot.... The new ARM-powered Windows 10 laptops that are supposedly coming this Christmas have a 32-bit x86 emulator only. The laptops won't run amd64 apps. On a 64-bit Snapdragon. [I understand the reason; I just think it is funny.]

No word yet on whether they'll support WSL. 😉

fpqc

fpqc commented on Sep 6, 2017

@fpqc

@therealkenc I sorta wonder if they could actually leverage what they already have with WSL to ARM64. If I remember correctly, ADSS was originally designed to emulate Android on Windows phone (running on an ARM). Ubuntu has an ARM port, and that kind of userspace would be a natural thing to use in a WSL for ARM64. I guess I'm saying that it's interesting since part of the work seems like it's already done!

therealkenc

therealkenc commented on Sep 6, 2017

@therealkenc

@fpqc - [Squarely in discussion tag territory] Yeah I yanked Ben's chain on that in #1769 (message). It would be fun to see for the amusement value, but my (sometimes flawed) powers of deductive reasoning say "nah". Ubuntu userland isn't the problem. The kernel is technically feasible. The problem is the target platform is the cheapest of cheap laptops. Not exactly a 'development use case scenario'. There's only 7-8 people on the team, and they need another target platform to support like they need a bullet in the head. Maybe I am jaded by the fact that I have seen this show before, and the ending is always the same. No not Windows 10 RT. I am old enough to have seen Windows NT 3.1 on MIPS. "This too will pass". Or, maybe I'm wrong. Maybe someone upstairs will tell the team different. Carry the OneCore torch and all that. Or maybe they'll do it for the amusement value. Or... maybe developers will run out in droves to buy Snapdraggon powered laptops this Christmas.

poizan42

poizan42 commented on Sep 6, 2017

@poizan42

32-bit support could be fixed for probably 99% of programs by making a custom glibc, which anyone who feels up for it could do:

You can in fact run 32-bit code in WSL land. If you do a far jump to segment 0x23 then you are executing code in compatibility mode (i.e. 32-bit mode) - do a far jump to 0x33 to get back in 64-bit land. The problem is that WSL only supports 64-bit syscalls, so 32-bit code attempting to make syscalls won't work (and you can't trap them either, see #1655). I have a small demonstration that this is possible here: https://gist.github.com/poizan42/8ff01d3df80b1663afef775ca812b699

So if someone feel up for it then it should be possible to port glibc to "lol64" (Linux on Linux 64) that jumps to 64-bit mode to perform all the syscalls, and it should work for everything except fully static binaries and the rare stuff that makes syscalls without going through glibc (some emulation software possibly)

therealkenc

therealkenc commented on Sep 7, 2017

@therealkenc

rare stuff that makes syscalls without going through glibc (some emulation software possibly)

Rare stuff, like gdb. Very cool hack though. #1655 was a good bug report by the way. I hope it gets addressed on the merits, nevermind the use case. Maybe ping a name-drop over there at some point. Good issue posts get lost/forgotten sometimes in all the noise.

MikeGitb

MikeGitb commented on Sep 7, 2017

@MikeGitb

[I understand the reason;

Actually I don't - That is, I can speculate, but if you have any actual information on this I would be thankful if you could share

therealkenc

therealkenc commented on Sep 7, 2017

@therealkenc

Well since you qualified the question, nope. I do not work at Microsoft, and even if I did, I couldn't share actual information like that. But I understand the reason.

MikeGitb

MikeGitb commented on Sep 8, 2017

@MikeGitb

@therealkenc: Just to be clear, with "actual" information I didn't mean "official" information, but more like "knowledge / reasonable assumptions I gathered from other posts or experience".

As I said, I myself can only speculate that it has to do with performance or reuse of code, but that is not even an educated guess, because I have no knowledge about where the pain points are when trying to run x86 or x64 code on an arm system or how Microsoft does it.

therealkenc

therealkenc commented on Sep 8, 2017

@therealkenc

There is never a single reason a company makes a decision. But my guess, for the price you've paid for it, is that it has at least partially to do with not running amok of instruction set patents with their emulator. 32-bit x86 is a smaller surface for Intel’s lawyers to attack, because most if not all of the juicy 32-bit x86 patents have expired. This makes the MSFT lawyer's jobs easier, and since these are low end battery optimised 4GB notebooks anyway, there is not a strong reason to make their lawyer’s jobs harder. It doesn't matter whether Intel has a legal leg to stand on, or not, of course. It would cost more for the in-house legal analysis, let alone risk a fight, than the entire engineering effort of the port.

My basis for this hypothesis is that Microsoft, Qualcomm, Lenovo, and the rest don't want to have to advertise the 32-bit limitation any more than you want to hear it. Whatever the technical challenges of doing an amd64 emulator, which I suspect are marginal in the scheme, they are not high enough to justify having to explain to customers and all the Arstechnicas and Engadgets of the world that the machines don't run x64/amd64 binaries. Thus, I think the reasons are at least in part non-technical.

I could be wrong, IANAL, and all that.....

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Zypp

Zypp commented on Sep 18, 2018

@Zypp

Based on some tinkering I was doing with qemu for some ARM dev, I think I may have found a technique to allow general 32-bit support in WSL. Hat-tip to @therealkenc for the concept 😁

Edit: requires "Fall Creators Update", 1709, build 16299 or newer (I think)

Presuming a fresh Ubuntu WSL instance, you'll need to install the qemu-user-static package, add the i386 binfmt, enable the i386 architecture, update your package lists, and install some i386 packages:

Install qemu and binfmt

sudo apt update
sudo apt install qemu-user-static
sudo update-binfmts --install i386 /usr/bin/qemu-i386-static --magic '\x7fELF\x01\x01\x01\x03\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x03\x00\x01\x00\x00\x00' --mask '\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xf8\xff\xff\xff\xff\xff\xff\xff'

[Edit: whoops, need to update package lists, added sudo apt update]

This will activate i386 support by causing them to be executed through qemu-i386-static, and drop a config file into /var/lib/binfmts/ for future reactivation.

You will need to reactivate this every time you restart WSL and want i386 support:

sudo service binfmt-support start

Enable i386 architecture and packages

sudo dpkg --add-architecture i386
sudo apt update
sudo apt install gcc:i386

Try it out

$ file /usr/bin/gcc-5
/usr/bin/gcc-5: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=2637bb7cb85f8f12b40f03cd015d404930c3c790, stripped

$ /usr/bin/gcc-5 --version
gcc-5 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc helloworld.c -o helloworld

$ ./helloworld
Hello, world!

$ file helloworld
helloworld: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=3a0c7be5c6a8d45613e4ef2b7b3474df6224a5da, not stripped

Proof

And to prove it really was working, disable i386 support and try again:

$ sudo service binfmt-support stop
 * Disabling additional executable binary formats binfmt-support [ OK ]

$ ./helloworld
-bash: ./helloworld: cannot execute binary file: Exec format error

This works like a charm, until I try to run my 32 bit executables in valgrind. My question already got shot down on stackoverflow for not being about programming. When I run valgrind I get qemu: uncaught target signal 11 (Segmentation fault) - core dumped. Is there a fix or alternative method? My valgrind supports 32 bit, I verified this like in the answers here.

drolevar

drolevar commented on Sep 27, 2018

@drolevar

I'm trying to launch java from openjdk-8-jre, and the java laucher cannot stat("/usr/lib/jvm/java-8-openjdk-i386/jre/lib/i386/server/libjvm.so"), which doesn't return 0.
But the file itself exists.
I guess it has something to do with qemu, but so far I had no luck figuring it out.

ad-on-is

ad-on-is commented on Oct 6, 2018

@ad-on-is

I'm trying to use an ARM-crosscompiler. Unfortunatelly, I get these errors:

/d/Projects/SamsungTV/arm/bin/arm-v7a8v4r3-linux-gnueabi-gcc AmbiLight.c hook.c -fPIC -O2 -std=gnu99 -I../include -ldl -shared -Wl,-soname,/d/Projects/SamsungTV/libAmbiLight/out-/libAmbiLight.so -o /d/Projects/SamsungTV/libAmbiLight/out-/libAmbiLight.so
/d/Projects/SamsungTV/arm/bin/../lib/gcc/arm-v7a8v4r3-linux-gnueabi/4.7.4/../../../../arm-v7a8v4r3-linux-gnueabi/bin/ld:/d/Projects/SamsungTV/arm/bin/../arm-v7a8v4r3-linux-gnueabi/sys-root/usr/lib/libdl.so: file format not recognized; treating as linker script
/d/Projects/SamsungTV/arm/bin/../lib/gcc/arm-v7a8v4r3-linux-gnueabi/4.7.4/../../../../arm-v7a8v4r3-linux-gnueabi/bin/ld:/d/Projects/SamsungTV/arm/bin/../arm-v7a8v4r3-linux-gnueabi/sys-root/usr/lib/libdl.so:1: syntax error
collect2: error: ld returned 1 exit status
Makefile:15: recipe for target '/d/Projects/SamsungTV/libAmbiLight/out-/libAmbiLight.so' failed
make: *** [/d/Projects/SamsungTV/libAmbiLight/out-/libAmbiLight.so] Error 1

EDIT:
Nevermind, this was caused due to the fact that I migrated from macOS to Windows, which messed up the symlinks. After downloading and extracting the toolchain in WSL, everything worked fine ;-)

yanygm

yanygm commented on Nov 4, 2018

@yanygm

基于一些修补,我正在使用qemu为一些ARM开发,我想我可能已经找到了一种技术来允许WSL中的一般32位支持。帽子提示@therealkenc的概念

编辑:需要“Fall Creators Update”,1709,build 16299或更新版(我认为)

假设一个新的Ubuntu WSL实例,您需要安装qemu-user-static软件包,添加i386 binfmt,启用i386架构,更新软件包列表,以及安装一些i386软件包:

安装qemu和binfmt

sudo apt update
sudo apt install qemu-user-static
sudo update-binfmts --install i386 /usr/bin/qemu-i386-static --magic '\x7fELF\x01\x01\x01\x03\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x03\x00\x01\x00\x00\x00' --mask '\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xf8\xff\xff\xff\xff\xff\xff\xff'

[编辑:哎呀,需要更新包列表,添加sudo apt update]

这将激活i386支持,使其通过qemu-i386-static执行,并删除配置文件/var/lib/binfmts/以备将来重新激活。

每次重新启动WSL并希望获得i386支持时,您都需要重新激活它:

sudo service binfmt-support start

启用i386架构和软件包

sudo dpkg --add-architecture i386
sudo apt update
sudo apt install gcc:i386

试试看

$ file /usr/bin/gcc-5
/usr/bin/gcc-5: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=2637bb7cb85f8f12b40f03cd015d404930c3c790, stripped

$ /usr/bin/gcc-5 --version
gcc-5 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc helloworld.c -o helloworld

$ ./helloworld
Hello, world!

$ file helloworld
helloworld: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=3a0c7be5c6a8d45613e4ef2b7b3474df6224a5da, not stripped

证明

要证明它确实有效,请禁用i386支持并再试一次:

$ sudo service binfmt-support stop
 * Disabling additional executable binary formats binfmt-support [ OK ]

$ ./helloworld
-bash: ./helloworld: cannot execute binary file: Exec format error

I hope to get 32-bit support on CentOS, what should I do?
image

Xinmudotmoe

Xinmudotmoe commented on Nov 5, 2018

@Xinmudotmoe

@yanygm

中文

update-binfmts本质是调用了Linux内核,而binfmt_misc属于Linux内核功能。

你可以在centos上编译binfmt-support,或者使用向/proc/sys/fs/binfmt_misc/register写入数据获得与update-binfmts相似的功能。

$ mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc 
 # 如果上一行执行后显示错误信息为already mounted,别管就行了。
$ echo :i386:M::'\x7fELF\x01\x01\x01\x03\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x03\x00\x01\x00\x00\x00':'\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xf8\xff\xff\xff\xff\xff\xff\xff':/usr/bin/qemu-i386-static: > /proc/sys/fs/binfmt_misc/register
 # 按照:name:type:offset:magic:mask:interpreter:flags的格式写入到/proc/sys/fs/binfmt_misc/register即可完成增加你想增加的binfmt_misc功能
$ echo 1 > /proc/sys/fs/binfmt_misc/status
 # 开启binfmt_misc功能(无论是否开启)
 # 现在 尝试运行32位程序应该没什么问题了

English translation

The essence of update-binfmts is to call the Linux kernel, and binfmt_misc is a Linux kernel feature.

You can compile binfmt-support on centos, or use the ability to write data to /proc/sys/fs/binfmt_misc/register to get similar functionality to update-binfmts.

$ mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc 
 # If the error message is displayed as always `mounted after` the previous line is executed, ignore it.
$ echo :i386:M::'\x7fELF\x01\x01\x01\x03\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x03\x00\x01\x00\x00\x00':'\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xf8\xff\xff\xff\xff\xff\xff\xff':/usr/bin/qemu-i386-static: > /proc/sys/fs/binfmt_misc/register
 # Write to /proc/sys/fs/binfmt_misc/register in the format:name:type:offset:magic:mask:interpreter:flags to increase the binfmt_misc feature you want to add.
$ echo 1 > /proc/sys/fs/binfmt_misc/status
 # Turn on the binfmt_misc function (whether or not it is enabled)
 # Now it’s okay to try to run a 32-Bit elf program.

image

Reference: Kernel Support for miscellaneous (your favourite) Binary Formats v1.1 — The Linux Kernel documentation
Reference: #2468 (comment)

Biswa96

Biswa96 commented on Nov 5, 2018

@Biswa96

@zhang1813023404 Does it retain after restarting WSL?

Xinmudotmoe

Xinmudotmoe commented on Nov 5, 2018

@Xinmudotmoe

@Biswa96 When you reboot the operating system, or restart WSL, the configuration will be invalidated. If you want to maintain state, you may need to configure the $HOME/.bashrc file.

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          I wonder if WSL will support the i386 (32 bit) program running later? · Issue #2468 · microsoft/WSL