./run -g almost fully ported in theory, not extensively tested

2026-01-25 19:21:35 +01:00 · 2018-08-27 00:26:43 +01:00
parent 561c08a286
commit 17c38b0c81
3 changed files with 184 additions and 216 deletions
--- a/README.adoc
+++ b/README.adoc
@@ -9,7 +9,7 @@
 :toclevels: 6
 :toc-title:

-Run one command, get a QEMU or gem5 Buildroot BusyBox virtual machine built from source with several minimal Linux kernel 4.18 module development example tutorials with GDB and KGDB step debugging and minimal educational hardware device models. "Tested" in x86, ARM and MIPS guests, Ubuntu 18.04 host.
+Run one command, get a QEMU or gem5 Buildroot BusyBox virtual machine built from source with several minimal Linux kernel 4.18 module development example tutorials with GDB and KGDB step debugging and minimal educational hardware device models. "Tested" in x86, ARM, Ubuntu 18.04 host.

 toc::[]

@@ -2392,8 +2392,6 @@ We also have one letter shorthand names for the architectures:
 ./run -a A
 # arm
 ./run -a a
-# mips64
-./run -a m
 # x86_64
 ./run -a x
 ....
@@ -2470,27 +2468,11 @@ but it fails with:
 a.out: line 1: syntax error: unexpected word (expecting ")")
 ....

-=== mips64
+=== MIPS

-Keep in mind that MIPS has the worst support compared to our other architectures due to the smaller community. Patches welcome as usual.
+We used to "support" it until f8c0502bb2680f2dbe7c1f3d7958f60265347005 (it booted) but dropped since one was testing it often.

-TODOs:
-
-* networking is not working. See also:
-** https://stackoverflow.com/questions/21496449/networking-is-not-working-on-qemu-guest-malta-mips
-** https://unix.stackexchange.com/questions/208266/setting-up-qemu-and-mipsel-networking-trouble
-** https://unix.stackexchange.com/questions/354127/qemu-mips-and-debian
-* <<gdb>> does not work properly, does not find `start_kernel`
-
-==== mips64 X11
-
-Haven't tried it, doubt it will work out of the box! :-)
-
-Maybe: https://stackoverflow.com/questions/47857023/booting-a-graphical-mips-qemu-machine
-
-==== mips64 gem5
-
-Haven't tried.
+If you want to revive and maintain it, send a pull request.

 == init

@@ -6462,8 +6444,6 @@ Source: link:rootfs_overlay/gpio.sh[]

 Buildroot's Linux tools package provides some GPIO CLI tools: `lsgpio`, `gpio-event-mon`, `gpio-hammer`, TODO document them here.

-Those broke MIPS build in 2017-02: https://bugs.busybox.net/show_bug.cgi?id=10276 and so we force disable them in our MIPS build currently.
-
 ==== LEDs

 TODO: broken when `arm`  moved to `-M virt`, same as <<gpio>>.
--- a/common.py
+++ b/common.py
@@ -113,11 +113,13 @@ def setup(parser):
    if args.arch in this.arch_map:
        args.arch = this.arch_map[args.arch]
    if args.arch == 'arm':
-        gem5_arch = 'ARM'
+        this.armv = 7
+        this.gem5_arch = 'ARM'
    elif args.arch == 'aarch64':
-        gem5_arch = 'ARM'
+        this.armv = 8
+        this.gem5_arch = 'ARM'
    elif args.arch == 'x86_64':
-        gem5_arch = 'X86'
+        this.gem5_arch = 'X86'
    this.buildroot_dir = os.path.join(root_dir, 'buildroot')
    this.arch_dir = args.arch
    if args.suffix is not None:
@@ -136,6 +138,7 @@ def setup(parser):
    this.qemu_guest_custom_dir = os.path.join(this.build_dir, 'qemu-custom')
    this.host_dir = os.path.join(this.buildroot_out_dir, 'host')
    this.images_dir = os.path.join(this.buildroot_out_dir, 'images')
+    this.ext2_file = os.path.join(this.images_dir, 'rootfs.ext2')
    this.qcow2_file = os.path.join(this.images_dir, 'rootfs.ext2.qcow2')
    this.staging_dir = os.path.join(this.buildroot_out_dir, 'staging')
    this.target_dir = os.path.join(this.buildroot_out_dir, 'target')
--- a/363
+++ b/363
@@ -1,8 +1,19 @@
 #!/usr/bin/env python3
+
+import base64
+
 import common
+import os
+import shlex
+import subprocess
+import sys
+
+# Argparse.
 parser = common.get_argparse(
    description='Run Linux on an emulator'
 )
+init_group = parser.add_mutually_exclusive_group()
+kvm_group = parser.add_mutually_exclusive_group()
 parser.add_argument(
    '-c', '--cpus', default=1, type=int,
    help='Number of guest CPUs to emulate. Default: %(default)s'
@@ -11,7 +22,7 @@ parser.add_argument(
    '-D', '--debug-vm', default=False, action='store_true',
    help='Run GDB on the emulator itself.'
 )
-parser.add_argument(
+kvm_group.add_argument(
    '-d', '--debug', default=False, action='store_true',
    help='Wait for GDB to connect before starting execution'
 )
@@ -49,7 +60,7 @@ Mnenomic: comes after `-e`.
 """
 )
 parser.add_argument(
-    '-G', '--gem5-exe-args',
+    '-G', '--gem5-exe-args', default='',
    help="""\
 Pass extra options to the gem5 executable.
 Do not confuse with the arguments passed to config scripts,
@@ -60,16 +71,15 @@ parser.add_argument(
    '--gem5-biglittle', default=False, action='store_true',
    help='Use fs_bigLITTLE.py instead of fs.py'
 )
-group = parser.add_mutually_exclusive_group()
-group.add_argument(
+init_group.add_argument(
    '-I', '--initramfs', default=False, action='store_true',
    help='Use initramfs instead of a root filesystem'
 )
-group.add_argument(
+init_group.add_argument(
    '-i', '--initrd', default=False, action='store_true',
    help='Use initrd instead of a root filesystem'
 )
-parser.add_argument(
+kvm_group.add_argument(
    '-K', '--kvm', default=False, action='store_true',
    help='Use KVM. Only works if guest arch == host arch'
 )
@@ -142,131 +152,121 @@ Run QEMU with VNC instead of the default SDL. Connect to it with:
 """
 )
 parser.add_argument(
-    'extra_emulator_args', nargs='?',
+    'extra_emulator_args', nargs='*',
    help='Extra options to append at the end of the emulator command line'
 )
 args = common.setup(parser)

-#if args.debug_vm:
-#    debug_vm="gdb -q -ex start --args"
-#if args.debug:
-#    extra_flags_qemu="${extra_flags_qemu} -S"
-#F)
-#    extra_append_after_dash="${extra_append_after_dash} lkmc_eval_base64=\"$(printf "${OPTARG}" | base64)\""
-#    ;;
-#f)
-#    extra_append_after_dash="${extra_append_after_dash} ${OPTARG}"
-#    ;;
-#if args.kgdb:
-#    extra_append="$extra_append kgdbwait"
-#if args.vnc:
-#    vnc = ['-vnc', ':0']
-#
-## nokaslr:
-## - https://unix.stackexchange.com/questions/397939/turning-off-kaslr-to-debug-linux-kernel-using-qemu-and-gdb
-## - https://stackoverflow.com/questions/44612822/unable-to-debug-kernel-with-qemu-gdb/49840927#49840927
-##   Turned on by default since v4.12
-#extra_append='console_msg_format=syslog nokaslr norandmaps panic=-1 printk.devkmsg=on printk.time=y'
-#
-## A dummy value that is already turned on by default and does not produce large output,
-## just to prevent QEMU from emitting a warning that '' is not valid.
-#trace_type=pr_manager_run
-#
-#
-#if "$debug" && "$kvm"; then
-#  echo 'error: -d and -K are incompatible' 1>&2
-#  exit 1
-#fi
-#if "$initrd" || "$initramfs"; then
-#  ramfs=true
+# nokaslr:
+# * https://unix.stackexchange.com/questions/397939/turning-off-kaslr-to-debug-linux-kernel-using-qemu-and-gdb
+# * https://stackoverflow.com/questions/44612822/unable-to-debug-kernel-with-qemu-gdb/49840927#49840927
+#   Turned on by default since v4.12
+kernel_cli_extra = 'console_msg_format=syslog nokaslr norandmaps panic=-1 printk.devkmsg=on printk.time=y'
+if args.kernel_cli_extra is not None:
+    kernel_cli_extra += ' {}'.format(args.kernel_cli_extra)
+
+# Common qemu / gem5 logic.
+env = os.environ.copy()
+kernel_cli_extra_after_dash = ''
+extra_args_qemu = []
+if args.debug_vm:
+    debug_vm = ['gdb', '-q', '-ex', 'start', '--args']
+else:
+    debug_vm = []
+if args.debug:
+    extra_args_qemu.append('-S')
+if args.kernel_cli_extra_after_dash_base64 is not None:
+    kernel_cli_extra_after_dash += ' lkmc_eval_base64="{}"'.format(base64.b64encode(args.kernel_cli_extra_after_dash_base64))
+if args.kernel_cli_extra_after_dash is not None:
+    kernel_cli_extra_after_dash += ' {}'.format(args.kernel_cli_extra_after_dash)
+if args.kgdb:
+    kernel_cli_extra += " kgdbwait"
+if args.vnc:
+    vnc = ['-vnc', ':0']
+if args.initrd or args.initramfs:
+    ramfs = True
+else:
+    ramfs = False
+if args.eval is not None:
+    if ramfs:
+        initarg = 'rdinit'
+    else:
+        initarg = 'init'
+    kernel_cli_extra += '{}=/eval_base64.sh'.format(initarg)
+    kernel_cli_extra_after_dash += ' lkmc_eval="{}"'.format(base64.b64encode(args.eval))
+if not args.graphic:
+    if args.arch == 'x86_64':
+        kernel_cli_extra += ' console=ttyS0'
+    extra_args_qemu.append('-nographic')
+if kernel_cli_extra_after_dash:
+    kernel_cli_extra += " - {}".format(kernel_cli_extra_after_dash)
+
+kernel_cli_extra_after_dash
+
+# A dummy value that is already turned on by default and does not produce large output,
+# just to prevent QEMU from emitting a warning that '' is not valid.
+trace_type = 'pr_manager_run'
+
+if args.gem5:
+    memory = '{}B'.format(args.memory)
+    gem5_exe_args = shlex.split(args.gem5_exe_args)
+    if args.trace is not None:
+        gem5_exe_args.append('--debug-flags={}'.format(args.trace))
+    env['M5_PATH'] = common.gem5_system_dir
+    cmd = (
+        debug_vm +
+        [
+            common.executable,
+            '--debug-file=trace.txt',
+        ] +
+        gem5_exe_args +
+        [
+            '-d', common.m5out_dir
+        ]
+    )
+    if args.gem5_biglittle:
+        # TODO port
+        # if args.gem5_restore_last_checkpoint is not None:
+        #     cmd += [
+        #         '--restore-from='${common.m5out_dir}/$(ls -crt "common.m5out_dir" | grep -E "common.gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1
+        #     ]
+        cmd += [
+            os.path.join(common.gem5_src_dir, 'configs', 'example', 'arm', 'fs_bigLITTLE.py'),
+            '--big-cpus', '2',
+            '--cpu-type', 'atomic',
+            '--disk', common.ext2_file,
+            '--dtb', os.path.join(common.gem5_system_dir, 'arm', 'dt', 'armv8_gem5_v1_big_little_2_2.dtb'),
+            '--kernel', common.vmlinux,
+            '--little-cpus', '2'
+        ]
+    else:
+        # TODO port
+        #if [ -n "$gem5_restore_last_checkpoint" ]; then
+        #    latest_cpt_basename="$(ls -crt "common.m5out_dir" | grep -E "common.gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1)"
+        #    n="$(ls -1 "common.m5out_dir" | grep -E "common.gem5_cpt_pref" | sort -k 2 -n -t . | grep -n "$latest_cpt_basename" | cut -d : -f 1)"
+        #    cmd += -r ${n} \\
+        cmd += [
+            os.path.join(common.gem5_src_dir, 'configs', 'example', 'fs.py'),
+            '--disk-image', common.ext2_file,
+            '--kernel', common.vmlinux,
+            '--mem-size', memory,
+            '--num-cpus', str(args.cpus),
+            '--script', common.gem5_readfile_file,
+        ]
+        if args.arch == 'x86_64':
+            if args.kvm:
+                cmd += ['--cpu-type', 'X86KvmCPU']
+            cmd += ['--command-line', 'earlyprintk=ttyS0 console=ttyS0 lpj=7999923 root=/dev/sda {}'.format(kernel_cli_extra)]
+        elif args.arch == 'arm' or args.arch == 'aarch64':
+            # TODO why is it mandatory to pass mem= here? Not true for QEMU.
+            # Anything smaller than physical blows up as expected, but why can't it auto-detect the right value?
+            cmd += [
+                '--command-line', 'earlyprintk=pl011,0x1c090000 console=ttyAMA0 lpj=19988480 rw loglevel=8 mem={} root=/dev/sda {}'.format(memory, kernel_cli_extra),
+                '--dtb-file', os.path.join(common.gem5_system_dir, 'arm', 'dt', 'armv{}_gem5_v1_{}cpu.dtb'.format(common.armv, args.cpus)),
+                '--machine-type', 'VExpress_GEM5_V1',
+            ]
 #else
-#  ramfs=false
-#fi
-#if [ -n "$lkmc_eval" ]; then
-#  if "$ramfs"; then
-#    initarg="rdinit"
-#  else
-#    initarg="init"
-#  fi
-#  extra_append="${extra_append} ${initarg}=/eval_base64.sh"
-#  extra_append_after_dash="${extra_append_after_dash} lkmc_eval=\"$(printf "$lkmc_eval" | base64)\""
-#fi
-#if "$nographic"; then
-#  if [ "$common_arch" = x86_64 ]; then
-#    extra_append="${extra_append} console=ttyS0"
-#  fi
-#  extra_flags_qemu="${extra_flags_qemu}-nographic \\
-#"
-#fi
-#if [ -n "$extra_append_after_dash" ]; then
-#  extra_append="${extra_append} - ${extra_append_after_dash}"
-#fi
-#
-#if "$common_gem5"; then
-#  memory="${memory}B"
-#  if "$trace_enabled"; then
-#    gem5opts="${gem5opts} --debug-flags='${trace_type}' \\
-#"
-#  fi
-#  gem5_common="\
-#M5_PATH='${common_gem5_system_dir}' \\
-#${debug_vm}\
-#'${common_executable}' \\
-#--debug-file=trace.txt \\
-#${gem5opts}\
-#-d '${common_m5out_dir}' \\
-#"
-#  if "$gem5_fsbiglittle"; then
-#    if [ -n "$gem5_restore_last_checkpoint" ]; then
-#      extra_flags="${extra_flags}\
-#--restore-from='${common_m5out_dir}/$(ls -crt "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1)' \\
-#"
-#    fi
-#    cmd="${gem5_common}\
-#"${common_gem5_default_src_dir}/configs/example/arm/fs_bigLITTLE.py" \\
-#--big-cpus=2 \\
-#--cpu-type=atomic \\
-#--disk="${common_images_dir}/rootfs.ext2" \\
-#--dtb "${common_gem5_system_dir}/arm/dt/armv8_gem5_v1_big_little_2_2.dtb" \\
-#--kernel="${common_vmlinux}" \\
-#--little-cpus=2 \\
-#"
-#  else
-#    if [ -n "$gem5_restore_last_checkpoint" ]; then
-#      latest_cpt_basename="$(ls -crt "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1)"
-#      n="$(ls -1 "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | sort -k 2 -n -t . | grep -n "$latest_cpt_basename" | cut -d : -f 1)"
-#      extra_flags="${extra_flags}-r ${n} \\
-#"
-#    fi
-#    gem5_common="\
-#${gem5_common}\
-#'${common_gem5_src_dir}/configs/example/fs.py' \\
-#--disk-image='${common_images_dir}/rootfs.ext2' \\
-#--kernel='${common_vmlinux}' \\
-#--mem-size='${memory}' \\
-#--num-cpus='${cpus}' \\
-#--script='${common_gem5_readfile_file}' \\
-#"
-#    if [ "$common_arch" = x86_64 ]; then
-#      if "$kvm"; then
-#        extra_flags="${extra_flags} --cpu-type=X86KvmCPU"
-#      fi
-#      cmd="\
-#${gem5_common}\
-#--command-line='earlyprintk=ttyS0 console=ttyS0 lpj=7999923 root=/dev/sda ${extra_append}' \\
-#"
-#    elif [ "$common_arch" = arm ] || [ "$common_arch" = aarch64 ]; then
-#      # TODO why is it mandatory to pass mem= here? Not true for QEMU.
-#      # Anything smaller than physical blows up as expected, but why can't it auto-detect the right value?
-#      cmd="${gem5_common}\
-#--command-line='earlyprintk=pl011,0x1c090000 console=ttyAMA0 lpj=19988480 rw loglevel=8 mem=${memory} root=/dev/sda ${extra_append}' \\
-#--dtb-file='${common_gem5_system_dir}/arm/dt/$([ "$common_arch" = arm ] && echo "armv7_gem5_v1_${cpus}cpu" || echo "armv8_gem5_v1_${cpus}cpu").dtb' \\
-#--machine-type=VExpress_GEM5_V1 \\
-#"
-#    fi
-#  fi
-#else
-#  mkdir -p "$common_qemu_run_dir"
+#  mkdir -p "common.run_dir"
 #  if [ -z "$debug_vm" ]; then
 #    serial_monitor="-serial mon:stdio \\
 #"
@@ -274,11 +274,11 @@ args = common.setup(parser)
 #    serial_monitor=
 #  fi
 #  if "$kvm"; then
-#    extra_flags="${extra_flags}-enable-kvm \\
+#    extra_args="${extra_args}-enable-kvm \\
 #"
 #  fi
 #  if "$kgdb"; then
-#    extra_flags_qemu="${extra_flags_qemu}-serial 'tcp::${common_gdb_port},server,nowait' \\
+#    extra_args_qemu="${extra_args_qemu}-serial 'tcp::${common_gdb_port},server,nowait' \\
 #"
 #  fi
 #  if "$prebuilt"; then
@@ -287,7 +287,7 @@ args = common.setup(parser)
 #  else
 #    qemu_executable="${common_qemu_exec}"
 #  fi
-#  extra_flags="${extra_flags_qemu}${extra_flags}"
+#  extra_args="${extra_args_qemu}${extra_args}"
 #  qemu_common="\
 #${debug_vm}\
 #${qemu_executable} \\
@@ -300,12 +300,12 @@ args = common.setup(parser)
 #-no-reboot \\
 #${serial_monitor}\
 #-smp '${cpus}' \\
-#-trace 'enable=${trace_type},file=${common_qemu_run_dir}/trace.bin' \\
+#-trace 'enable=${trace_type},file=${common_run_dir}/trace.bin' \\
 #-virtfs 'local,path=${common_9p_dir},mount_tag=host_scratch,security_model=mapped,id=host_scratch' \\
 #-virtfs 'local,path=${common_buildroot_out_dir}/build,mount_tag=host_out,security_model=mapped,id=host_out' \\
 #${vnc}"
 #  if "$initrd"; then
-#    extra_flags="${extra_flags} -initrd '${common_images_dir}/rootfs.cpio' \\
+#    extra_args="${extra_args} -initrd '${common_images_dir}/rootfs.cpio' \\
 #"
 #  fi
 #
@@ -314,31 +314,29 @@ args = common.setup(parser)
 #    # TODO why is this needed, and why any string works.
 #    root='root=/dev/anything'
 #  else
-#    if [ ! "$common_arch" = mips64 ]; then
-#      if [ -n "$rr" ]; then
-#        driveif=none
-#        rrid=',id=img-direct'
-#        root='root=/dev/sda'
-#        snapshot=
-#      else
-#        driveif=virtio
-#        root='root=/dev/vda'
-#        rrid=
-#        snapshot=,snapshot
-#      fi
-#      extra_flags="${extra_flags}-drive 'file=${common_qcow2_file},format=qcow2,if=${driveif}${snapshot}${rrid}' \\
+#    if [ -n "$rr" ]; then
+#      driveif=none
+#      rrid=',id=img-direct'
+#      root='root=/dev/sda'
+#      snapshot=
+#    else
+#      driveif=virtio
+#      root='root=/dev/vda'
+#      rrid=
+#      snapshot=,snapshot
+#    fi
+#    extra_args="${extra_args}-drive 'file=${common_qcow2_file},format=qcow2,if=${driveif}${snapshot}${rrid}' \\
 #"
-#      if [ -n "$rr" ]; then
-#        extra_flags="${extra_flags}\
+#    if [ -n "$rr" ]; then
+#      extra_args="${extra_args}\
 #-drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \\
 #-device ide-hd,drive=img-blkreplay \\
 #"
-#      fi
 #    fi
 #  fi
 #
 #  if [ -n "$rr" ]; then
-#    extra_flags="${extra_flags}\
+#    extra_args="${extra_args}\
 #-object filter-replay,id=replay,netdev=net0 \\
 #-icount 'shift=7,rr=${rr},rrfile=${common_qemu_rrfile}' \\
 #"
@@ -347,23 +345,23 @@ args = common.setup(parser)
 #    virtio_gpu_pci="-device virtio-gpu-pci \\
 #"
 #  fi
-#  case "$common_arch" in
+#  case "args.arch" in
 #    x86_64)
 #      if "$kgdb"; then
-#        extra_append="${extra_append} kgdboc=ttyS0,115200"
+#        kernel_cli_extra="${kernel_cli_extra} kgdboc=ttyS0,115200"
 #      fi
 #      cmd="\
 #${qemu_common}\
 #-M pc \\
-#-append '${root} nopat ${extra_append}' \\
+#-append '${root} nopat ${kernel_cli_extra}' \\
 #-device edu \\
 #"
 #    ;;
 #    arm|aarch64)
 #      if "$kgdb"; then
-#        extra_append="${extra_append} kgdboc=ttyAMA0,115200"
+#        kernel_cli_extra="${kernel_cli_extra} kgdboc=ttyAMA0,115200"
 #      fi
-#      if [  "$common_arch" = arm ]; then
+#      if [  "args.arch" = arm ]; then
 #        cpu=cortex-a15
 #      else
 #        cpu=cortex-a57
@@ -373,39 +371,28 @@ args = common.setup(parser)
 #      cmd="\
 #${qemu_common}\
 #-M virt,highmem=off \\
-#-append '${root} ${extra_append}' \\
+#-append '${root} ${kernel_cli_extra}' \\
 #-cpu "$cpu" \\
 #${virtio_gpu_pci}\
 #"
 #    ;;
-#    mips64)
-#      if ! "$ramfs"; then
-#        root='root=/dev/hda'
-#        extra_flags="${extra_flags}-drive 'file=${common_qcow2_file},format=qcow2${snapshot}' \\
-#"
-#      fi
-#      cmd="\
-#${qemu_common}\
-#-M malta \\
-#-append '${root} ${extra_append}' \\
-#-cpu I6400 \\
-#"
-#    ;;
 #  esac
 #fi
-#if "$tmux"; then
-#  if "$common_gem5"; then
-#    eval "./tmu 'sleep 2;./gem5-shell -n ${common_run_id} ${tmux_args};'"
-#  elif "$debug"; then
-#    eval "./tmu ./rungdb -a '${common_arch} -L ${common_linux_variant}' -n ${common_run_id} ${tmux_args}"
-#  fi
-#fi
+
+print(' \\\n'.join(cmd))
+subprocess.check_output(cmd, env=env)
+
+#if args.tmux:
+#    if args.gem5:
+#        eval "./tmu 'sleep 2;./gem5-shell -n ${common_run_id} ${tmux_args};'"
+#    elif args.debug:
+#        eval "./tmu ./rungdb -a '${common_arch} -L ${common_linux_variant}' -n ${common_run_id} ${tmux_args}"
 #if [ -n "${1:-}" ]; then
-#  extra_flags="${extra_flags}${@} \\
+#  extra_args="${extra_args}${@} \\
 #"
 #fi
 #cmd="time \\
-#${cmd}${extra_flags}"
+#${cmd}${extra_args}"
 #if [ -z "$debug_vm" ]; then
 #  cmd="${cmd}\
 #|& tee >(ts -s %.s > ${common_termout_file})\
@@ -416,17 +403,15 @@ args = common.setup(parser)
 #if [ "$cmd_out" -ne 0 ]; then
 #  exit "$cmd_out"
 #fi
-#
+
+# TODO
 ## Check if guest panicked.
-#if "$common_gem5"; then
-#  # We have to do some parsing here because gem5 exits with status 0 even when panic happens.
-#  #
-#  # Grepping for '^panic: ' does not work because some errors don't show that message
-#  panic_msg='--- BEGIN LIBC BACKTRACE ---$'
-#else
-#  panic_msg='Kernel panic - not syncing'
-#fi
-#if grep -E -e "$panic_msg" -q "$common_termout_file"; then
-#  echo 'Simulation error detected by parsing logs. Exiting with status 1.'
-#  exit 1
-#fi
+#if args.gem5:
+#    # We have to do some parsing here because gem5 exits with status 0 even when panic happens.
+#    # Grepping for '^panic: ' does not work because some errors don't show that message.
+#    panic_msg = '--- BEGIN LIBC BACKTRACE ---$'
+#else:
+#    panic_msg = 'Kernel panic - not syncing'
+#if grep -E -e "$panic_msg" -q "common.termout_file"; then
+#    print('Simulation error detected by parsing logs. Exiting with status 1.', file=sys.stderr)
+#    sys.exit(1)