User Tools

Site Tools


developersguide:crosscompiling

Crosscompiling MINIX with build.sh

Build compatibility

Host platform Buildable MINIX architectures
Ubuntu x86 32-bit x86 32-bit / ARMv7
Ubuntu x86 64-bit x86 32-bit / ARMv7
Arch Linux x86 32-bit x86 32-bit
Arch Linux x86 64-bit x86 32-bit / ARMv7
Mac OS X Lion x86 64-bit x86 32-bit / ARMv7
FreeBSD 10-CURRENT x86 32-bit x86 32-bit / ARMv7
FreeBSD 10-CURRENT x86 64-bit x86 32-bit / ARMv7

NetBSD

The first step to crosscompile MINIX is to obtain the sources and build the crosscompilation tools. MINIX has adopted NetBSD's build.sh script to create the crosscompiler. There are some wrapper scripts that will build a ready-to-boot system from scratch (i.e. just the minix source tree) for either x86 or ARM.

First fetch the sources:

$ git clone git://git.minix3.org/minix minixsrc
$ cd minixsrc

Crossbuilding for x86

The wrapper script for x86 generates a harddisk image ready to boot - except that it currently relies on an outside multiboot implementation. KVM provides this. It's very convenient also for passing args from the outside into the VM. The script produces a lot of output and will take a long time the first time - it generates a cross-toolchain from scratch based on LLVM.

$ bash ./releasetools/x86_hdimage.sh 
[..]
Writing Minix filesystem images
 - ROOT
 - USR
 - HOME
Part     First         Last         Base      Size       Kb
  0      0/000/00     0/000/07         0         8        4
  1      0/000/08    64/000/07         8    131072    65536
  2     64/000/08  1856/000/07    131080   3670016  1835008
  3   1856/000/08  1984/000/07   3801096    262144   131072
To boot this image on kvm:
[..]

The printed kvm command line loads all the boot modules in the right order, sets the right variables (minix needs to know the rootdevname) and sets the console for serial.

Crossbuilding for ARM

A similar procedure exists for ARM. Please see MinixOnARM for much more information.

Using build.sh directly

From a source directory:

$ sh build.sh -mi386 -O ../build tools

Please note that by default, the build.sh script will output the built objects to /usr/obj, so make sure it exists. Alternatively, use as above the “-O” option to redirect the output to somewhere else. When this process is completed, you'll have a ../build/tooldir.<something> directory. The <something> is roughly equivalent to

$ echo ''uname -s''-''uname -r''-''uname -m''

Among the tools that are built are gcc, binutils, and gmake. The sources for these tools are not provided by us. Instead, they are downloaded on-the-fly as tarballs from the minix webserver

Note: For Cross compiling on Ubuntu , an extra library is to be installed , i.e the zlibc To install it run the following command :

$ sudo apt-get install zlibc zlib1g zlib1g-dev

Note: Also on Ubuntu, if you get an error stating that “'/lib/cpp' fails sanity check”, you need to install the GNU C++ compiler:

$ sudo apt-get install g++

Building world

The next step is to actually build MINIX:

$ sh build.sh -mi386 -O ../build -U distribution

This process will create a ../build/destdir.i386 directory that holds the built distribution of MINIX.

Other useful options for qemu are -monitor telnet::4444,server,nowait (to access some interesting internal state by telnet) and -serial stdio - for convenient debug output over 'serial.'

Compiling things without build.sh

To run make in the cross-environment, i.e. to rebuild a tool (host target) or minix item (minix target), without running the full build.sh procedure all over again, use nbmake-i386, a make wrapper that sets all the right environment. First expand your $PATH to include it:

$ PATH=$PATH:OBJDIR/tooldir.OS-VERSION-ARCH/bin/
$ cd SRCDIR/tools
$ nbmake-i386 clean
$ nbmake-i386

will rebuild all the tools. After that you can e.g.

$ cd zic
$ nbmake-i386 clean
$ nbmake-i386

to just rebuild zic. As you can tell if you set MAKEVERBOSE=2, tools/zic/ will invoke cc (to run on the host platform), whereas nbmake-i386 will invoke i486–netbsdelf-gcc from your tools dir if you run it in usr.sbin/zic/, so a Minix-targeted binary is produced.

Caveats

The build.sh is tailored towards NetBSD and as such not all features make sense for MINIX. For example, we don't have a kernel configuration file. Also, you can't use build.sh for native builds on MINIX at the time of this writing. You can consult build.sh's documentation by invoking:

$ sh build.sh

But know that not all operations and options are supported. For example, we only support the distribution build operation. You can't generate iso images with the build.sh script.

Build flags for build.sh

It is possible to tweak the build using build flags. Here are some you might find useful.

Option name value example Description
COPTS c flags COPTS=-g c compiler opttions

Build flags for nbmake

It is also possible to tweak when building separate components using nbmake-i386

Option name value example Description
MAKEVERBOSE [1] MAKEVERBOSE=2 Instruct make to be more verbose

Mounting a MINIX disk image on Linux

1. Load the loop kernel module, or adapt kernel commandline:

$ modprobe loop max_part=15

or add to your kernel commandline : max_part=15

2. Setup a loopback device to point to your disk image:

$ losetup /dev/loop0 minix.img

3. (Optional) list the available partitions:

$ dmesg | tail

or use

$ ls /dev/loop0*

4. Mount the desired partition somwhere

$ mount /dev/loop0p5 /mnt
developersguide/crosscompiling.txt · Last modified: 2014/11/12 11:20 by lionelsambuc