Re: [Qemu-devel] ANN: DetaolB v0.4 is released

[Rob Landley <rob@landley.net>]

On Saturday 30 June 2007 13:15:44 Blue Swirl wrote:
> On 6/30/07, Thiemo Seufer <ths@networkno.de> wrote:
> > Johannes Schindelin wrote:
> > > Hi,
> > >
> > > On Sat, 30 Jun 2007, Blue Swirl wrote:
> > > > On 6/30/07, Christian MICHON <christian.michon@gmail.com> wrote:
> > > > > DetaolB aimed to be a "much-less-than-a-floppy" x86 linux live
> > > > > distro. Now, it's evolving more into "a-la-slax" type of distro.
> > > >
> > > > As the number of Sparc32 distributions keeps approaching zero, could
> > > > you consider porting DetaolB to non-x86 CPUs?
> > >
> > > Yes, please!
> >
> > The reason why distributions drop sparc32 is the unmaintained kernel.
> > Nobody stepped up for Linux kernel maintenance in the last years.
> > Debian managed to keep up a sort-of working kernel for the last
> > release, the people who put their time into it are disinclined to
> > repeat this exercise.
>
> But there is a difference in maintaining a kernel suitable for high
> quality distribution with over 18733 packages working in different
> real hardware, versus a test/evaluation distribution with <30 packages
> running on Qemu. I'd see that as an "enhanced qemu-tests.tar.gz".

Just FYI, Firmware Linux builds for sparc and has for months now.

http://landley.net/code/firmware

Go "./build.sh sparc", and wait a bit.  It even generates a run-sparc.sh in 
the build directory that'll invoke qemu against the kernel and ext2 image it 
generated.

That creates a sparc cross compiler, uses it to build a root filesystem 
containing a native toolchain for sparc, and packages it into an ext2 image.  
Over on arm I've built binutils and gcc natively inside the emulator.

The sparc platform has a problem that if I boot with init as a "hello world" 
program everything behaves as expected (there are two in the image for 
testing purposes, /tools/bin/hello-dynamic and /tools/bin/hello-static).  But 
if you boot with init=/tools/bin/bash it hangs.  And so do the busybox 
shells.

I think it's a uClibc bug on sparc, but haven't made time to track it down.  
Either that or the kernel needs something _weird_ for console initialization.  
(The cross-compiler and kernel seem to be working fine...)

You can try it out yourself by downloading all the *sparc* files from 
http://landley.net/code/firmware/downloads/images and then running:

qemu-system-sparc -nographic -no-reboot -hda image-sparc.ext2 -kernel \
  zImage-sparc -append 'rw init=/tools/bin/hello-dynamic panic=1 \
  PATH=/tools/bin root=/dev/sda console=ttyS0'

That prints "Hello world!", panics, and exits.

./run-sparc.sh does the exact same command line with "init=/tools/bin/sh" 
(bash 2.05b), which hangs.  Note that init=/tools/bin/ash (busybox ash) does 
the same thing.  Haven't debugged beyond that yet...

Rob

P.S.  I gave a tutorial about this system at OLS, and my lecture notes are at 
http://landley.net/ols/ols2007/tutorial.txt
-- 
"One of my most productive days was throwing away 1000 lines of code."
  - Ken Thompson.