Hi,

I'm doing some webassembly things. I was trying to register webassembly
as a miscellaneous binary format so that we can run wasm files like a
regular binary. There's a guide
<https://docs.kernel.org/admin-guide/binfmt-misc.html> online about how to
do that but I was stuck on the first step: mounting binfmt_misc.

After some digging we found that in kernel modules
<https://git.alpinelinux.org/aports/tree/main/linux-lts/lts.x86_64.config>
CONFIG_BINFMT_MISC is set to 'm', but I found that some other
architectures<https://github.com/search?q=repo%3Atorvalds%2Flinux+CONFIG_BINFMT_MISC&type=code>
set it to 'y', does this change things? How do I configure my machine to be
able to add a miscellaneous binary format? I've tried googling but none of
the results have a clear solution to this. Any help would be appreciated,
thanks in advance.

Mathu Xu

On Thu, 2024-09-12 at 15:32 -0400, Mathu Xu wrote:
> After some digging we found that in kernel modules
> <https://git.alpinelinux.org/aports/tree/main/linux-lts/lts.x86_64.config>
> CONFIG_BINFMT_MISC is set to 'm', but I found that some other
> architectures<https://github.com/search?q=repo%3Atorvalds%2Flinux+CONFIG_BINFMT_MISC&type=code>
> set it to 'y', does this change things?

Hi,

"m" is for a loadable module
"y" is for the module build into the kernel

You can load the module on demand by running

# modprobe module_name

or at startup.

"/etc/init.d/modules loads all modules specified in /etc/modules and
/(etc|run|usr/lib|lib)/modules-load.d/*.conf"
  - https://wiki.alpinelinux.org/wiki/Architecture#Boot_Process

Regards,
Ralf