[Clfs-dev] why there isn't any standard CLFS ARM Book?

[Andrew Bradford]

Hi Michele,

On Wed, Nov 21, 2018 at 7:10 PM Michele Bucca <michele.bucca at gmail.com> wrote:
> I was wondering why there wasn't a regular CLFS book for the ARM
> architecture. Yes, we have clfs-embedded but we don't have a regular
> CLFS Book. The only architectures supported are x86, x86_64, sparc,
> mips, but not ARM. Why?

There's no normal CLFS book for ARM because no one has taken the time
to create it.  I assume that if you did add to the existing CLFS book
to add the ARM architecture and send patches that someone would review
the patches and apply them, although this may take some time as no
CLFS book developers are very active these days.  But maybe your
updates to add ARM to CLFS would spurn a new round of interest?  Who
knows?

If you're interested in it, give it a try.  In the worst case you'll
learn something new.

> Nowadays there are a lot of ARM based Single Board Computers like the
> Raspberry Pi so I think that maybe the ARM community would benefit
> from a book like this.

Possibly.  Although I'd argue that CLFS itself isn't that popular for
any of the architectures it supports in any of the book guises these
days.  Enough "normal" distributions support ARM systems now that
getting desktop/server operation isn't all that hard any more and for
more embedded and resource constrained systems there are many
semi/fully automated build systems which are widely used and have
decently sized developer communities around them.

> I know that there's a PiLFS project out there, but it's not a book,
> rather a set of scripts that build LFS for the RPI. Still it's a
> pretty useful resource.
>
> I'm having trouble building a Cross-compiler for ARMv7 (soft float)
> using the latest packages used in LFS-8.3, glibc-2.28. I don't know if
> you're interested in helping me with my problem. I Tried to build a
> toolchain for ARMv5 (also soft float) and glibc builds fine if I
> disable werrors. The toolchain can build several packages such as
> busybox, binutils, make, GCC but it fails with *tar*.

For your failing package builds, have you looked at the patches which
are used to build those packages in Debian?
Debian supports ARM and everything builds for them so it can be a good
place to find patches, if any are needed.

> If I had a book maybe it would be easier for me to build a working
> toolchain without this kind of issues. Let me guess, ARM processors
> have too many differences between them and it is difficult to build a
> book that works for all of them, right? Let me know what you think. I
> really like the ARM architecture and it would be a shame for me to
> abandon it.

If you need a toolchain that works and want to rule that part out, why
not start by using an off the shelf toolchain and try to bootstrap
yourself?
For example, start with Debian's cross toolchains to build your base
system up enough that it can host its own toolchain and then go from
there.  Or if you're not interested in a glibc system, take one of the
off the shelf alternative libc toolchain tools (musl-cross works well:
https://github.com/GregorR/musl-cross) and start with that.

Thanks,
Andrew