Using qemu syscall emulation with Debian.
Chapter 3 - Going further

3.1 Trouble-shooting

If qemu-arm fails mysteriously, try to run it under strace. It might tell you if it look for a file in the wrong place.

Note that qemu-arm will not run scripts. This is not really a limitation since script have a hard-coded path to the interpretor which will point to the native version.

Current qemu really does not like symlink to directories in the directory pointed by -L.

3.2 Installing extra packages

If you want to install more packages, you can download them with this variant of debget (that I will call debget-arm).

     #!/bin/bash -e
     
     for pkgspec in $*; do
       version=$(apt-get -q2 -s --reinstall install "$pkgspec" | grep ^Inst | sed -ne '$s/^.*\[\(.*\)\].*$/\1/p')
       echo "($pkgspec -> $version)"
       aptdata=$(apt-get -q2 --print-uris --reinstall install "$pkgspec" | tail -1|sed -e "s/_i386\.deb/_arm\.deb/g")
       echo $aptdata
       url=$(echo "$aptdata" | sed -e "s/^'\([^']*\)'.*$/\1/")
       file=$(echo "$aptdata" | sed -e "s/^'[^']*' \([^ ]*\).*$/\1/")
       echo $url
       echo $file
       curl "$url" > "$file"
     done

This script assume your first apt source is a Debian archive that include the arm architecture and the packages are in sync on arm. As an example I will try to get pari-gp running: I run

     mkdir debs; cd debs;
     debget-arm libpari1 libx11-6 libreadline4 pari-gp
     cd ..
     for pkg in debs/*; do \
     echo "Extracting $pkg..."; dpkg-deb -x $pkg ARM; done

To access libraries in ARM/usr/X11R6/lib, you need to change your LD_LIBRARY_PATH variable:

     export LD_LIBRARY_PATH=/scratch/qemu/ARM/usr/X11R6/lib

Now, you can try

     qemu-arm -L /scratch/qemu/ARM ARM/usr/bin/gp
     
                       GP/PARI CALCULATOR Version 2.1.6 (released)
                   arm running linux (C portable kernel) 32-bit version

As a comparaison of performance, debussy.debian.org runs the PARI/GP benchmark in 17246ms. A Athlon 1800+ running qemu-arm run the benchmark in 14730ms. The native binary run in 1340ms.

Using qemu syscall emulation with Debian.