Re: Proposal, again: Disable autoload of compat_xyz modules

["Thomas Mueller" <mueller6725%twc.com@localhost>]

from Kamil Rytarowski:

> My primary motivation is running LTP kernel regression tests for
> compat_linux and integrate them into ATF (src/tests).

> With musl it is posible to get cross-toolchain for the same CPU
> configuration as host without building customized gcc/clang.

> >>> Did you cross-compile from NetBSD to get the cross-toolchain, or did =
> you need some Linux stuff already compiled?

> >> I compiled everything natively on NetBSD, from NetBSD. No Linux stuff
> >> precompiled.

> > Did you not need Linux compat at this stage?


> No. It was needed only to test hello-world example.

> Such musl-gcc approach to build non-trivial applications will most
> likely fail as we will still be detected as NetBSD and this will affect
> the end result.

I guess I need to go to musl-libc.org website and their git site.

I remember seeing something about cross-compiling, also saw some bad links.

> For building applications with dependencies we will need to do it at
> least in chroot.

Applications would be built and installed into a separate sysroot.

Question is whether such a sysroot could run mounted on /emul/linux, as well as in its own partition or USB stick.

> However.. getting this setup to build larger packages with plain
> musl-gcc is viable. It's a matter of cost vs benefit here.

I am still not sure whether I do better with musl as opposed to glibc.

> > How does the compiler at NetBSD end know what OS to compile for?  Is it=
>  a matter of the appropriate tuple or triplet?

> ELF is similar on NetBSD and Linux, the are few differences that are
> handled with musl-gcc GCC script.

> However it would involve some work to build non-trivial applications.

> >>> But I believe you would need Linux kernel headers in any case.

> >> This might be the case that the Linux kernel headers needed that are
> >> GPLv2. If so, it will be easier and quicker to get
> >> MUSL+LTP+GMAKE+LINUX_HEADERS|(+BASH+....) as a package in pkgsrc.

> > I found musl, uclibc and glibc in pkgsrc/wip .  One is not likely to ge=
> t far building packages with pkgsrc, or FreeBSD with ports, without gmake=
>  and bash.

> > Linux headers would not have to be built, but it would be necessary to =
> configure and build the Linux kernel.


> Building the Linux kernel with musl-gcc can be more tricky as there are
> certainly hacks assuming uname=3DLinux.

> However... it should be doable.

> > Perhaps, musl could be downloaded from their website and compiled.

> I was wondering whether there would be a use-case for integration of
> MUSL into src/?

> >> Implementing everything as a part of src/ is possible, but needs more
> >> work and more GPL code around.

> >>> Where do you get musl-gcc, or is it built as part of the light cross-=
> toolchain?

> It is part of the musl git repo.

> https://git.musl-libc.org/cgit/musl/

> There is need to build musl-gcc.specs.sh and musl-gcc

> https://git.musl-libc.org/cgit/musl/tree/Makefile

> I had to run "gmake musl-gcc" "gmake musl-gcc.specs" or similar. I would
> need to reproduce it or package to recall the exact commands.

> I had to install musl into /usr/local + the ELF leader link into
> /lib/ld-musl*.


Tom