[ECOS] Re: Linux synthetic target build errors

[Grant Edwards <grant dot b dot edwards at gmail dot com>]

On 2010-05-01, Aziz Bodal <azizbodal@gmail.com> wrote:

> I am writing a paper for a Real-time OS class on comparing the
> scheduling algorithms of two real-time operating systems. The RTOS
> systems I am comparing are eCOS and FreeRTOS. I need to run a
> multi-threaded application and compare some statistics.
>
> I am a newbie at this so please excuse my ignorance. I am looking for
> a good emulator so that I can compare these two operating systems.

Qemu works nicely for eCos.

I found the easiest way to to it was to create a bootable CD ISO image
and then tell Qemu to boot from that.

Build your application using "grub" startup mode.

Then you can use the shellscript below to run it.  The script creates
the bootable CD containing the grub bootloader and the eCos
application specified on the commandline.  Then it runs Qemu using
that CD image.

------------------------------runit.sh------------------------------
#!/bin/bash
#set -x

# a shell script to run in the Qemu PC emulator an eCos
# application that's been built with "Grub" startup mode for the
# pc_rltk8239 target.
#
# The program to be run is $1.  It runs Qemu with the no-graphics
# option and with a single serial port connected to a telnet
# server socket.
#
# An instance of the "aterm" X11 terminal emulator is started with
# telnet command to connect to that virtual serial port.
#
# TUN/TAP networking is used to create a point-to-point Ethernet link
# to the virtual machine.  The host end is 172.16.0.1, so you should
# configure the eCos build to use a static 172.16.0.x network address.
#
# The script could be modified to bridge the virtual TAP interface 
# with a physcial interface if you want to make the virtual machine
# accessible from other hosts.  Or you could start a DHCP server on 
# the TAP interface so that you don't have to build apps with static
# IP configurations.

# set this to point to your grub el torito stage 2 file
ElToritoStage2=/lib/grub/i386-pc/stage2_eltorito

function StartQemu {
  # create a TAP interface belonging to the user
  User=$USER
  TAP=$(sudo /usr/bin/tunctl -b -u $User)
  sudo /sbin/ifconfig $TAP 172.16.0.1 promisc up
  # try to load the kqemu module to speed up emulation
  sudo /sbin/modprobe kqemu
  # start the emulator using the TAP interface we created above
  qemu -net nic,model=rtl8139  -net tap,ifname=$TAP,script=no -nographic $*
  # remove the TAP interface
  sudo /usr/bin/tunctl -d $TAP
  }

test -f $ElToritoStage2 || { echo "grub el torito stage 2 file not found"; exit 1; }

test -z "$TEMP" && TEMP=/tmp

# create a bootable ISO image with Grub configured to load the program

ProgPath="$1"
Prog=$(basename "$ProgPath")
Iso=$TEMP/grub-$$.iso
Tree=$TEMP/grub-$$-tree

# we want to end up with an ISO image with this structure:
#
# /
# |-- boot
# |   `-- grub
# |       |-- menu.lst
# |       `-- stage2_eltorito
# `-- eCosApplication

# create the empty directry "tree" (only has the one branch)
mkdir -p $Tree/boot/grub

# copy Grub stage2 file
cp $ElToritoStage2 $Tree/boot/grub

# create Grub configuration file that loads program
cat >$Tree/boot/grub/menu.lst <<EOF
serial --unit=0 --speed=115200
terminal --timeout=2 serial console
default 0
timeout 1
title  /$Prog
kernel /$Prog
EOF

# application goes in "root" directory, and stripping it will
# speed up loading
cp $ProgPath $Tree
strip $Tree/$Prog 

# create the bootable ISO9660 image
mkisofs -quiet -R -b boot/grub/stage2_eltorito -no-emul-boot \
   -boot-load-size 4 -boot-info-table -o $Iso $Tree
   
# done with the tree
rm -rf $Tree

# start a terminal that will telnet to the virtual machine's serial port
(sleep 0.5; aterm -title "eCos Serial 0" -name "eCos Serial 0" -e telnet localhost 9876)&

# start the emulator
StartQemu -boot cdrom -cdrom $Iso -serial telnet:localhost:9876,server

# clean up
rm -rf $Iso
--------------------------------------------------------------------


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