[Arm-dev] Work in progress ARM v7 port

Robert Moskowitz rgm at htt-consult.com
Tue Feb 17 19:17:08 UTC 2015

Great to see this.

You could be using the Fedora 21 arm builds and source for your starting 
point.  It has direct installation on a number of cards. You have to dig 
a bit on the Fedora download site to find them, but they are there.

Or go with F22 beta that is just starting.  This has the advantage of a 
newer uboot and 3.19 kernel; both give better support for a number of 
boards, including work on the Banana Pi R1 (makes a great router).

F22 can be gotten from 

Now I use the Cubieboards.  These have sata, so you can have even better 
performance and safety than working with an SD card.  I have a number 
running both Redsleeve 6 and Fedora 21.  Anything with the Allwinner 
SoC, you want F22 uboot and kernel to get video support (I am having 
problems with the usb disconnecting and waiting for a fix on that).

Raspberry Pi 2 work is also being done with F22 (well Rawhide until 
today when F22 build got approved for beta).

Check out the Fedora-arm list for what has been going on there.

But great to see this post.

On 02/17/2015 01:48 PM, Howard Johnson wrote:
> Hello all.  Recently I've been having a bit of fun trying to port 
> CentOS 7 to ARMv7, and I thought I'd share info on what I've been 
> doing with the list.
> As a long-time Red Hat family distribution user, I've been interested 
> in a CentOS build for ARM since the release of the originally 
> Raspberry Pi.  However, it's only with the release of RHEL 7 that a 
> source code base that largely works on ARM has been available to 
> CentOS [1].  The announcement and release of the new, faster, 
> quad-core ARMv7-based Raspberry Pi 2 sounded like an ideal reason to 
> have a go at making a CentOS-like RHEL rebuild for ARM, so I ordered a 
> couple of Pi 2s, and started having a think about how I'd go about 
> building EL7.
> Having been on the periphery of the CentOS project for quite a while, 
> I knew how CentOS 7 was built: the RHEL 7 sources were rebuilt 
> multiple times; first against the public RHEL 7 beta, then against the 
> results of this build, then against then those results, and so on.  
> Ideally, a similar process could be used to built EL7 for ARM, but of 
> course there has never been a RHEL 7 release for ARM of any sort.  
> Fortunately, Fedora 19, which RHEL 7 was forked from, does have a 
> public (and functional) ARM release. So an EL7 ARM port can be 
> bootstrapped from the Fedora binary RPMs.
> Of course, before I could start rebuilding CentOS sources, I'd need an 
> OS image to rebuild on.  Fortunately, the Raspberry Pi's bootloader 
> system is pretty simple: the Pi's firmware looks for specifically 
> named files in the VFAT-formatted first partition of the SD card.  The 
> Fedora 19 Minimal image has an ext4 /boot partition which is easily 
> reformatted, and populated with the contents of /boot from the Pi 2 
> Rasbian image, and the kernel modules to go with the Rasbian-shipped 
> kernel copied to the ext4 / filesystem.  A quick (not really) dd of 
> the image to an SD card, and I had a booting Pi 2.  The next step was 
> to test out running mock to build Fedora 19 chroots ready to build 
> packages in. Testing showed that it took the Pi roughly 8m30s to 
> create a basic F19 mock chroot on the SD card.
> At the same time as starting out working with the Pi 2, a friend 
> pointed me at the ODROID C1 [2], a Pi-like small ARM board.  The C1 
> has a couple of advantages over even the Pi 2: it has a somewhat 
> faster CPU [3], but, more importantly, it has on-SoC gigabit ethernet 
> [4].  The ODROID is designed and manufactured by Hardkernel in South 
> Korea. The ODROID is a bit more expensive (£33 from a UK supplier [5] 
> versus the £25 Pi 2), but still quite affordable. Realising that 
> building RPMs on a Pi on the SD card or over the network would be very 
> slow, I ordered a C1 to try.
> I was really rather pleased with the C1 when it arrived.  After trying 
> and failing to modify the Fedora 19 ARM Minimal image with an 
> ODROID-specific kernel [6], I ended up grabbing an F21 image made by 
> one of the ODROID forum members [7].  The (one of the) nice thing(s) 
> about building RPMs in mock is that as long as the host OS can run 
> mock, it doesn't really matter what the host OS is, so a Fedora 21 OS 
> for the C1s is fine.
> Of course, even the ODROID wouldn't be able to make mock chroots very 
> quickly on their SD card, but the built-in gigabit ethernet makes 
> another option quite sensible: iSCSI.  By mounting a block device [8] 
> from a server over iSCSI, the C1 can create an F19 chroot in about 
> 2m40s.  Having decided the C1 was better for the builder job than the 
> Pi 2, I borrowed another C1 from my friend, and put an order in for 
> two more.
> In the meantime, I made a start on building packages using the C1. The 
> sensible starting point was building the C7 versions of the packages 
> that go into the basic mock build chroot.  The basic idea here is that 
> the sooner that the set of packages used to build all packages is 
> replaced with the C7 versions, the closer the OS will be to a "true" 
> C7 OS [9]. Once this base set was built, the order of the remaining 
> 1000+ SRPMs is a bit less critical, and more at the mercy of my random 
> whims [10].  I should also note that I'm concentrating on building the 
> CentOS 7 GA package set, not any of the updates.  Once I have a C7 GA 
> package set I'm happy with, then I'll look at all the package updates 
> from GA to current.
> I was originally planning to knock up a script or two to wrap mock and 
> do createrepo runs.  Instead I decided to dust off Plague, the old 
> build system Seth Vidal and co wrote for Fedora Extras. Plague takes 
> care of managing a queue of SRPMs to distribute to multiple builders, 
> running builds, collecting resulting logs and RPMs, and making yum 
> repos.  Plague is a tad old, and needed a few code changes to support 
> ARM architectures.  It's also a bit... tempremental at times, as the 
> central manager process has issues spotting when builders come and go, 
> but overall it's done quite well.
> So what's the current status of the rebuild effort?  Of the 2481 SRPMs 
> in CentOS 7.0.1406 (the GA C7 release), 1125 don't need to be rebuilt 
> for ARM, either because they're entirely noarch packages [11], or 
> because they're listed as either "exclusivearch", which means they 
> should only be built on a specific list of architectures [12].  Of the 
> remaining 1356 packages, 943 have been successfully rebuilt, 62 have 
> failed to build, and 351 haven't been attempted yet.  Thus far only 
> two RPMs have needed to be modified: centos-release had to be altered 
> to not conflict with the Fedora 19 systemd (both packages contain 
> /usr/lib/systemd/system-preset/90-default.preset), but is now replaced 
> with the stock C7 version, and elfutils has had its test suite 
> disabled [13].  Very much on the positive side, after a 36 hour build, 
> the third build attempt of libreoffice completed successfully [14].
> The other thing that's worth saying is that I've not yet looked at any 
> ARM-specific "special" stuff, like an ARM kernel build, or any 
> bootloader support.  That's potentially hard stuff, and will take some 
> thinking about [15].
> I'm planning to put the various hacky scripts I'm using into a github 
> repo or similar, and I'll be posting status updates in the future with 
> how I get on.
> Cheers!
> [1] RHEL6's Fedora 12/13-derived codebase largely predates the Fedora 
> ARM effort, whereas the Fedora 19 base of RHEL 7 had an actively 
> maintained ARM secondary architecture; fixes to Fedora packages for 
> ARM were incorporated into Fedora proper, and RHEL 7 inherited these 
> fixes.
> [2] 
> http://www.hardkernel.com/main/products/prdt_info.php?g_code=G141578608433
> [3] Four 1.5GHz cores versus the Pi 2's four 900MHz cores.
> [4] Contrasting with the Pi's fast ethernet adapter wired to the 
> onboard USB hub.
> [5] http://www.lilliputdirect.com/odroid-c1-quad-core-computer
> [6] Not helped by me not having bought a serial cable, so I couldn't 
> watch the bootloader messages.
> [7] http://forum.odroid.com/viewtopic.php?f=114&t=8872
> [8] SSD backed, using a Samsung EVO 850 SATA SSD.
> [9] To the point where it might save an entire OS rebuild cycle, which 
> will be a not inconsiderate amount of effort.
> [10] For example, one night I queued up all SRPMs with names starting 
> with "lib"; unfortunately I forgot that that would include libreoffice...
> [11] So we can use the C7 builds unmodified.
> [12] Packages in this group are generally platform-specific packages 
> like efibootmgr or dmidecode which make no sense on ARMv7 platforms.
> [13] Due to a single failing test that wasn't run in the Fedora 19 
> elfutils build.
> [14] The first died when the C1 ran out of RAM, which made me add 
> iSCSI-backed swap to all the builders, while the second ended when I 
> found that the libreoffice build requires more than 16GB of space; on 
> the bright side I found out that the iSCSI LUNs can be resized 
> entirely online.
> [15] Apologies for all the footnotes, I like them.

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