Troubles with Cross Compiling and portage

MarkCu · n00b Joined: 28 Nov 2012 Posts: 19

All,

Some background - I'm trying to prepare for a gentoo install on a Raspberry Pi 3, per the instructions here:
https://wiki.gentoo.org/wiki/Raspberry_Pi

I'm trying to follow the "Cross Compile" options instead of using QEMU/chroot.

(My background - I understand cross compiling environments quite well. I'm a mediocre portage user. I'm able to maintain my various gentoo boxes - both real and virtual - without too much fumbling about. I understand at a high level well portage is doing, but don't get into the nitty gritty details all too often. I've hacked an ebuild once or twice successfully)

The cross-compiled environment is setup, and seems to work - (cross toolchain installed, and tested).

I'm moving on to doing my first cross-compile emerge, per the instructions. I've setup my CBUILD, CHOST, ROOT, and PORTAGE_CONFIGROOT are all set. I run the emerge and it fails quickly:

Mr. T. · Guru Joined: 26 Dec 2016 Posts: 477

Hello MarkCu!

NeddySeagoon · Posted: Sat Oct 21, 2017 10:59 am Post subject:

MarkCu,

This guide covers fetching, building and installing the kernel for a Raspberry Pi 3 in 64 bit mode.

Where that guide says

NeddySeagoon · Posted: Sat Oct 21, 2017 10:59 am Post subject:

Moved from Portage & Programming to Gentoo on ARM.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Mr. T. · Guru Joined: 26 Dec 2016 Posts: 477

It seems that the migration to git-r3 (eclass) broke the ebuilds.

MarkCu · n00b Joined: 28 Nov 2012 Posts: 19

After realizing the ebuild didn't work even in my normal X86 hosts - I just ended up using git to manually pull down the Raspberry Pi sources, and manually installing them under /usr/src/linux. From my (very novice) read of the ebuild - I don't think it's applying any patches - just doing the git download.

@NeddySeagoon - thanks for the pointer to the 64-bit mode guide. However, I followed the advice in the header of that guide - noting that this should all be considered unstable. My thinking was that the 32-bit support should be more stable, and require less hacking on my part. (And nothing that I'm going to do with my first instance of the Pi would justify the need for 64-bit). I'm quickly learning that whatever solution I end with - will require (perhaps significant) hacking.

I have bootable (32-bit) image now running gentoo on the Pi. But am still having a devil of a time getting everything up at the moment. No specific show-stoppers that I don't think I can handle. It's just taken quite a bit more hacking that I imagined. Biggest problem is I can't get portage to build gcc. It's not worked in crossdev, qemu/chroot, nor NATIVELY on the Pi. I've had to add the --exclude gcc to many emerge operations.

But I'm hacking through things.

Thanks for the help.

--Mark

NeddySeagoon · Posted: Mon Oct 23, 2017 5:54 pm Post subject:

MarkCu,

Cross compiling gcc itself can be a challenge but it should build on the Pi.
You will probably need MAKEOPTS="-j1" and no Xorg running or you are likely to trigger the OOM manager, which will kill a compile job.
Look in dmesg ... you won't miss it there.

The build log will say something about job ... killed.

Homework: Portage can manage per package MAKEOPTS settings, and many others too.
Set up your system to build gcc without setting MAKEOPTS either in make.conf or on the command line.
You will need this approach for a number of packages.

64 bit mostly works on the Pi. The biggest problem is that you don't know until you try it as a lot of things are not keyworded.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.