Tag Archives: Raspberry Pi

From 0 to Raspberry Pi Linux in 45 Minutes

I thought it would be cool to see how long it takes to make a boot-able Raspberry Pi disk using ELLCC. This is a timed experiment. In the end we’ll have an SD card that can be booted on the Pi. First, get a binary ELLCC release:

[~/ellcc-release] dev% mkdir test
[~/ellcc-release] dev% cd test
[~/test] dev% wget http://ellcc.org/releases/ellcc-x86_64-linux-eng-0.1.27.tgz
--2016-01-12 22:00:19--  http://ellcc.org/releases/ellcc-x86_64-linux-eng-0.1.27.tgz
Resolving ellcc.org (ellcc.org)... 174.102.201.124
Connecting to ellcc.org (ellcc.org)|174.102.201.124|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 650187071 (620M) [application/x-gzip]
Saving to: ‘ellcc-x86_64-linux-eng-0.1.27.tgz’

ellcc-x86_64-linux-e 100%[=====================>] 620.07M  11.0MB/s   in 56s    

2016-01-12 22:01:15 (11.1 MB/s) - ‘ellcc-x86_64-linux-eng-0.1.27.tgz’ saved [650187071/650187071]
[~/test] dev% tar xvfp ellcc-x86_64-linux-eng-0.1.27.tgz

Second, check what the options are:

[~/test] dev% cd ellcc/libecc/ecclinux/
[~/test/ellcc/libecc/ecclinux] dev% ./build 
usage: ./build [options] target
  options:
    -packages 'packag1 package2 ...'    Specific packages to build
    -exclude  'packag1 package2 ...'    Specific packages to exclude
    -extras                             Include additional packages
    -clean                              Clean up a previous build
  targets:
    help                                This message
    bcmrpi                              Raspberry Pi    (ARMv6)
    bcm2709                             Raspberry Pi 2  (ARMv7)
  available packages:
    kernel sinit sbase ubase smdev nldev nlmon svc sdhcp loksh
          ntfs3g iproute2 e2fsprogs vim dropbear
  extra packages:
    ellcc
  packages not buildable on the Mac:
    uboot iproute2 e2fsprogs vim

Third, build an image for the Pi 2 that includes the ELLCC tool chain (-extras):

[~/test/ellcc/libecc/ecclinux] dev% ./build -extras bcm2709j
...

Fourth, insert an SD card and install:

[~/test/ellcc/libecc/ecclinux] dev% su
Password: 
[root@dev ecclinux]# ./install
Warning! This command will destroy all data on /dev/sdc.
Continue? [yes/no] yes
...

Put the SD in the Pi and boot. Voila!

Cross Building Linux With ELLCC: Part 5 – Making an SD Card to Boot the Pi.

UPDATE: A more streamlined version of this process is available: From 0 to Raspberry Pi Linux in 45 Minutes

In previous posts I’ve described building the Linux kernel using ELLCC, building Linux for a Raspberry Pi B+, building Linux for the Pi 2, and building Linux on a Mac. In this post we’ll build enough userland and create an SD card that will boot on the Raspberry Pi 2. I just got it to boot this evening and it only gets to the login prompt where I can log in as root, but I think it is pretty cool nonetheless.

I mentioned the ellcc/libecc/ecclinux directory that is in the ELLCC source tree and is included in the ELLCC binary distributions. In this directory, there is a little script that will get sources for the Linux kernel from kernel.org, and a bunch of userland programs from suckless.org and other places. The script will then patch the sources if necessary and build them.

These are the steps I took to create a boot-able SD card. I happened to have a 32 Gig SD card lying around, so I decided to use it. On my Linux box, an SD card shows up as /dev/sdc* so the following commands reflect that. Your system may assign different name. You should verify the name by using df, or something similar, to determine what a newly inserted SD card is.

I’m going to go into a bit of detail here because it is the first time I did this for Linux and I want to keep a detailed record.

UPDATE: I made a little script that populates the SD card. It is in the source repository. The script replaces/enhances the rest of this post.

The first thing I did was to remove the old partitions on the card.

  sudo parted /dev/sdc print
    Model: Generic- SD/MMC (scsi)
    Disk /dev/sdc: 32.1GB
    Sector size (logical/physical): 512B/512B
    Partition Table: msdos
    Disk Flags: 

    Number  Start   End     Size    Type     File system  Flags
     1      512B    62.9MB  62.9MB  primary
     2      62.9MB  67.1MB  4209kB  primary

My card had 2 partitions that I got rid of:

  sudo parted /dev/sdc rm 1
    Information: You may need to update /etc/fstab.

  sudo parted /dev/sdc rm 2
    Information: You may need to update /etc/fstab.

  sudo parted /dev/sdc print                                       
    Model: Generic- SD/MMC (scsi)
    Disk /dev/sdc: 32.1GB
    Sector size (logical/physical): 512B/512B
    Partition Table: msdos
    Disk Flags: 

    Number  Start  End  Size  Type  File system  Flags

Now that the old partitions are gone, we can make new partitions for the Pi. The Pi boots using two partitions, one is in MS-DOS or FAT format, the other is in Linux ext4 format. The Pi has an interesting boot sequence, which is nicely described on this page, but basically the GPU starts up first and executes a first and second stage boot loader, which is really the GPU’s OS, before the ARM is brought up and the Linux kernel is booted. The FAT partition is used by the GPU and contains all the files it needs. The ext4 partition contains the rest of the Linux userland. The FAT partition os mounted as /boot after the ext4 partition is mounted as /.So the next step is to create these two partitions. First the FAT partition:

sudo parted -a optimal /dev/sdc unit chs mkpart primary 0,130,2 8,40,31
sudo parted /dev/sdc set 1 lba on

Now we can fill the rest of the disk with the ext4 partition:

sudo parted -a optimal /dev/sdc mkpart primary 67.1MB 100%

Now we’ll format the file systems:

  sudo mkfs -t fat /dev/sdc1
    mkfs.fat 3.0.27 (2014-11-12)

Then the ext4 partition:

  sudo mkfs -t ext4 /dev/sdc2
    mke2fs 1.42.12 (29-Aug-2014)
    Creating filesystem with 7820288 4k blocks and 1957888 inodes
    Filesystem UUID: 3823b7f5-66b6-4e9f-a10e-4a6658d6469f
    Superblock backups stored on blocks: 
            32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
            4096000

    Allocating group tables: done                            
    Writing inode tables: done                            
    Creating journal (32768 blocks): done
    Writing superblocks and filesystem accounting information: done   

We have to mark the first partition as the boot partition:

  sudo parted /dev/sdc set 1 lba on
    Information: You may need to update /etc/fstab.

  sudo parted /dev/sdc print
    Model: Generic- SD/MMC (scsi)
    Disk /dev/sdc: 32.1GB
    Sector size (logical/physical): 512B/512B
    Partition Table: msdos
    Disk Flags: 

    Number  Start   End     Size    Type     File system  Flags
     1      4194kB  67.1MB  62.9MB  primary  fat16        lba
     2      67.1MB  32.1GB  32.0GB  primary  ext4

Now we can populate the card. First, build everything using the script. If you run the script with no arguments, it will give you a hint about how to run it:

[~] dev% cd ellcc/libecc/ecclinux
[~/ellcc/libecc/ecclinux] dev% ./build 
usage: ./build [options] target
  options:
    -packages 'packag1 package2 ...'    Specific packages to build
    -exclude  'packag1 package2 ...'    Specific packages to exclude
    -clean                              Clean up a previous build
  targets:
    help                                This message
    bcmrpi                              Raspberry Pi    (ARMv6)
    bcm2709                             Raspberry Pi 2  (ARMv7)
  available packages:
    uboot kernel sinit sbase ubase smdev nldev nlmon svc sdhcp loksh
          ntfs3g iproute2 e2fsprogs vim ellcc
  packages not buildable on the Mac:
    uboot iproute2 e2fsprogs vim

In this case I’ll build for the Raspberry Pi 2:

[~/ellcc/libecc/ecclinux] dev% ./build bcm2709
  CHK     include/config/kernel.release
  GEN     ./Makefile
  CHK     include/generated/uapi/linux/version.h
  CHK     include/generated/utsrelease.h
  Using /home/rich/ellcc/libecc/ecclinux/linux-4.1.15 as source for kernel
...

The SD card can be populated after the build completes:

 
  mkdir boot root
  sudo mount /dev/sdc1 boot
  sudo mount /dev/sdc2 root
  cp -r image/arm-linux-engeabihf/bcm2709/* boot
  sudo cp boot/vmlinuz-4.1.15-v7 boot/kernel7.img
  cd image/arm-linux-engeabihf/
  tar cvfp - bin etc lib sbin usr var | (cd ../../root; sudo tar xfp -)
  cd cm2709/
  rm -fr *.old
  tar cvfp - * | ( cd ../../../boot ; sudo tar xfp - )
  cd ../../..
  cd etc
  chmod oug+x rc.*
  cp * ../root/etc/
  cd ../sbin
  tar cvfp - * | ( cd ../root/sbin/ ; sudo tar xf - )
  cd ../bin
  chmod oug+x *
  tar cvfp - * | ( cd ../root/bin/ ; sudo tar xf - )
  sudo cp boot.rpi/* boot/
  cd root
  sudo mkdir root proc sys var/run
  sudo mknod dev/tty0 c 4 0
  cd ..
  sudo umount boot root

I popped the SD card into my Pi 2 and finally got the login: prompt. The initial root password is empty.

This has been a busy weekend. I got a boot, the Packers won, and it is late Sunday night and I have to work early tomorrow. I will be making the SD create steps into a script soon, but for now I’ll put up a new binary release of ELLCC, version 0.1.26, that has all the changes if you want to try this out.

Cross Building Linux With ELLCC: Part 3 – Other Flavors of Pi

Update: Cross Building Linux With ELLCC: Part 4 – Building Linux on the Mac
In my last post I described using ELLCC to build Linux for the Raspberry Pi B+. In ELLCC version 0.1.24 I added a script to build Linux for both the Pi B+ and the Pi 2. As a bonus, the script also builds a bunch of userland programs

First grab the latest binary release:

[~] dev% wget http://ellcc.org/releases/ellcc-x86_64-linux-eng-0.1.24.tgz
[~] dev% tar xvfp ellcc-x86_64-linux-eng-0.1.24.tgz

Now decide what target to build:

[~] dev% cd ellcc/libecc/ecclinux/
[~/ellcc/libecc/ecclinux] dev% ls
00_rpilinux-4.1.15.patch   bin/    etc/            makefile      sbin/
99_llvmlinux-4.1.15.patch  build*  iproute2.patch  ntfs3g.patch  sinit/
[~/ellcc/libecc/ecclinux] dev% ./build 
usage: ./build [options] target
  options:
    -nokernel           Don't build the Linux kernel
    -clean              Clean up a previous build
  targets:
    help                This message
    bcmrpi              Raspberry Pi    (ARMv6)
    bcm2709             Raspberry Pi 2  (ARMv7)
[~/ellcc/libecc/ecclinux] dev%

Run the build command again, with the board you need as an argument (I’m going to time the build with time):

[~/ellcc/libecc/ecclinux] dev% time ./build bcm2709
... (lots of output removed)
4984.143u 435.744s 22:52.57 394.8%      0+0k 704+4154968io 2pf+0w
[~/ellcc/libecc/ecclinux] dev% 

As SpongeBob would say, “23 minutes later.” When the build is finished, the ecclinux directory looks like this:

[~/ellcc/libecc/ecclinux] dev% ls
00_rpilinux-4.1.15.patch   bin/       etc/            linux-4.1.15/  sbin/
99_llvmlinux-4.1.15.patch  build*     image/          makefile       sinit/
arm-linux-engeabihf/       download/  iproute2.patch  ntfs3g.patch
[~/ellcc/libecc/ecclinux] dev%

There are three new directories: download/ contains tar files that have been downloaded in case you need them again, arm-linux-engeabihf/ is where the build was made for the ARMv7, and image/ is where the binaries were installed. Let’s take a look at image/arm-linux-engeabihf/:

[~/ellcc/libecc/ecclinux] dev% ls image/arm-linux-engeabihf/
bcm2709/  bin/  etc/  lib/  sbin/  usr/  var/
[~/ellcc/libecc/ecclinux] dev% 

The bcm2709/ directory is what will be in the /boot directory in the final Raspberry Pi 2 SD image. It has Pi 2 specific files in it, including the kernel:

[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev% ls bcm2709/
dtbs/  System.map-4.1.15-v7  vmlinuz-4.1.15-v7
[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev%

Here’s what the bin and sbin directories look like:

[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev% ls bin/ sbin/ 
bin/:
[*           ed*           ksh*         nltrigger*   sha256sum*    tty*
basename*    eject*        last*        nohup*       sha512sum*    umount*
cal*         env*          lastlog*     od*          sleep*        uname*
cat*         ex@           link*        pagesize*    smdev*        unexpand*
chattr*      expand*       ln*          passwd*      sort*         uniq*
chgrp*       expr*         logger*      paste*       split*        unlink*
chmod*       fallocate*    login*       pidof*       sponge*       unshare*
chown*       false*        logname*     pivot_root*  stat*         uptime*
chroot*      find*         ls*          printenv*    strings*      uudecode*
chvt*        flock*        lsattr*      printf*      su*           uuencode*
cksum*       fold*         lsmod*       ps*          swaplabel*    uuidgen*
clear*       free*         lsusb*       pwd*         swapoff*      view@
cmp*         freeramdisk*  md5sum*      readahead*   swapon*       vim*
cols*        fsfreeze*     mesg*        readlink*    switch_root*  vimdiff@
comm*        getconf*      mkdir*       renice*      sync*         vimtutor*
cp*          getty*        mkfifo*      respawn*     sysctl*       vtallow*
cron*        grep*         mknod*       rm*          tail*         watch*
ctrlaltdel*  halt*         mkswap*      rmdir*       tar*          wc*
cut*         head*         mktemp*      rmmod*       tee*          which*
date*        hostname*     mount*       run_nldev*   test*         who*
dd*          hwclock*      mountpoint*  rview@       tftp*         whoami*
df*          id*           mv*          rvim@        time*         xargs*
dirname*     insmod*       nice*        sed*         touch*        xxd*
dmesg*       join*         nl*          seq*         tr*           yes*
du*          kill*         nldev*       setsid*      true*
echo*        killall5*     nlmon*       sha1sum*     truncate*

sbin/:
badblocks*   findfs@        mke2fs*            ntfs-3g.secaudit*  resize2fs*
blkid*       fsck*          mkfs.ext2@         ntfs-3g.usermap*   routef*
bridge*      fsck.ext2@     mkfs.ext3@         ntfscat*           routel*
ctstat@      fsck.ext3@     mkfs.ext4@         ntfsclone*         rtacct*
debugfs*     fsck.ext4@     mkfs.ext4dev@      ntfscluster*       rtmon*
dumpe2fs*    fsck.ext4dev@  mkfs.ntfs@         ntfscmp*           rtpr*
e2freefrag*  genl*          mklost+found*      ntfscp*            rtstat@
e2fsck*      ifcfg*         mkntfs*            ntfsfix*           sdhcp*
e2image*     ifstat*        mount.lowntfs-3g@  ntfsinfo*          sinit*
e2label@     ip*            mount.ntfs-3g@     ntfslabel*         ss*
e2undo*      lnstat*        nstat*             ntfsls*            tune2fs*
e4defrag*    logsave*       ntfs-3g*           ntfsresize*        uuidd*
filefrag*    lowntfs-3g*    ntfs-3g.probe*     ntfsundelete*
[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev%

Not bad for 23 minutes of work!

If you want to try the kernel on your Pi 2, you need to copy vmlinuz-4.1.15-v7 to the Rasbian /boot directory as kernel7.img. In my case, my Pi 2 is at 192.124.43.100 so I can do this:

[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev% scp bcm2709/vmlinuz-4.1.15-v7 root@192.124.43.100:/boot/kernel7.img
root@192.124.43.100's password: 
vmlinuz-4.1.15-v7                              100% 4355KB   4.3MB/s   00:00    
[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev%

After a reboot:

[rich@dev ~]$ ssh root@192.124.43.100
root@192.124.43.100's password: 

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Fri Jan  1 17:28:43 2016 from 192.124.43.2
root@raspberrypi:~# dmesg | less
[    0.000000] Booting Linux on physical CPU 0xf00
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 4.1.15-v7 (rich@dev) (ecc 0.1.24 based on clang version 3.8.0 (trunk) (based on LLVM 3.8.0svn)) #1 SMP Mon Jan 4 20:45:34 CST 2016

Not bad. To complete the kernel update you’ll also want to update the kernel modules:

[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev% ls lib/modules/4.1.15-v7/
kernel/            modules.builtin      modules.dep.bin  modules.softdep
modules.alias      modules.builtin.bin  modules.devname  modules.symbols
modules.alias.bin  modules.dep          modules.order    modules.symbols.bin
[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev% scp -r lib/modules/4.1.15-v7/ root@192.124.43.100:/lib/modules
root@192.124.43.100's password: 
Permission denied, please try again.
root@192.124.43.100's password: 
modules.symbols                                100%  146KB 146.2KB/s   00:00    
modules.dep                                    100%  131KB 131.1KB/s   00:00  
...
modules.builtin.bin                            100% 5903     5.8KB/s   00:00    
modules.builtin                                100% 4341     4.2KB/s   00:00    
[~/ellcc/libecc/ecclinux/image/arm-linux-engeabihf] dev%

Reboot again and even the mouse and keyboard work.

In Part 4, I’ll show how to make the SD image and use the userland programs that we’ve built. In the mean time you can copy them to the Pi’s SD card and use them.

Cross Building Linux With ELLCC: Part 2 – Raspberry Pi B+

Update: Cross Building Linux With ELLCC: Part 3 – Other Flavors of Pi
In a previous post I tested the waters to see how close ELLCC is to cross compiling the Linux kernel. That post was mostly a theoretical exercise to see what it would take. Over the holidays I decided that I needed to do something a little more concrete. My son, a 10 year old obsessed with Minecraft, got a Raspberry Pi for Christmas. My nefarious plan is to divert his attention away from Minecraft at least long enough to make his Pi and camera module into something he can use to spy on the family. My other nefarious plan is to use ELLCC to build the Linux kernel that we’ll be running on his Pi.

In the previous post I used the source from the LLVMLinux site. This time I started with the kernel source for the Raspberry Pi. The good news is that the source can be built for the Pi. The bad news is that it doesn’t have all the patches need to compile with a clang based compiler. It turned out that the build wasn’t too bad: I had Christmas Eve and Day off and in between family events and Santa preparations I was able to massage the source enough to boot the kernel on our Pi.

To get started I followed the instructions on Linux From Scratch on the Raspberry Pi.
Here are the exact steps I took. First I created a new directory to hold the ELLCC tool chain and the Raspberry Linux kernel source, then I downloaded and untar’d both:

mkdir ecclinux
cd ecclinux
wget http://ellcc.org/releases/ellcc-x86_64-linux-eng-0.1.23.tgz
tar xvfp ellcc-x86_64-linux-eng-0.1.23.tgz
wget https://github.com/raspberrypi/linux/archive/rpi-4.1.y.tar.gz
tar xvfp rpi-4.1.y.tar.gz

I had to change the kernel sources slightly during my build. I saved a patch
file, here’s how to apply it:

patch -p0 < ellcc/libecc/llvmlinux/ecc-rpi-4.1.y.patch

There is a special little 'm' makefile that helps with the build. Copy
it into the top level of the kernel source directory:

cd linux-rpi-4.1.y/
cp ../ellcc/libecc/llvmlinux/makefile .

Now the actual build is easy:

make bcmrpi_defconfig
make

I have my Raspberry Pi on my home network at 192.124.43.98. I also allowed ssh
and scp root access by follwoing the instructions here. This lets me
just copy the new kernel to my Pi:

scp ./arch/arm/boot/zImage root@192.124.43.98:/boot/kernel.img

Now I can ssh to the Pi and reboot:

[~] dev% ssh root@192.124.43.98
root@192.124.43.98's password: 

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
root@raspberrypi:~# reboot
Connection to 192.124.43.98 closed by remote host.
Connection to 192.124.43.98 closed.
[~] dev%

I ping the Pi until it reboots and log in again:

[~] dev% ssh root@192.124.43.98
root@192.124.43.98's password: 

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sat Dec 26 20:27:15 2015 from 192.124.43.2
root@raspberrypi:~# dmesg | less
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 4.1.15 (rich@dev) (ecc 0.1.23 based on clang version 3.8.0 (trunk) (based on LLVM 3.8.0svn)) #1 Sat Dec 26 11:32:33 CST 2015
[    0.000000] CPU: ARMv6-compatible processor [410fb767] revision 7 (ARMv7), cr=00c5387d
...

Very nice!