gem5: support variants

run

@@ -34,7 +34,7 @@ trace_enabled=false
 # just to prevent QEMU from emitting a warning that '' is not valid.
 trace_type=pr_manager_run
 vnc=
-while getopts a:c:DdE:e:F:f:G:ghIiKkL:m:PT:U:uVx OPT; do
+while getopts a:c:DdE:e:F:f:G:ghIiKkL:M:m:PT:U:uVx OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
@@ -94,6 +94,9 @@ while getopts a:c:DdE:e:F:f:G:ghIiKkL:m:PT:U:uVx OPT; do
     L)
       common_linux_variant="$OPTARG"
       ;;
+    M)
+      common_gem5_variant="$OPTARG"
+      ;;
     m)
       memory="$OPTARG"
       ;;
@@ -124,8 +127,7 @@ while getopts a:c:DdE:e:F:f:G:ghIiKkL:m:PT:U:uVx OPT; do
 done
 shift "$(($OPTIND - 1))"
 extra_flags="$extra_flags $@"
-set_common_vars -L "$common_linux_variant" "$arch" "$gem5"
-images_dir="${buildroot_out_dir}/images"
+set_common_vars -L "$common_linux_variant" -M "$common_gem5_variant" "$arch" "$gem5"
 if "$debug" && "$kvm"; then
   echo 'error: -d and -K are incompatible' 1>&2
   exit 1
@@ -156,9 +158,6 @@ if [ -n "$extra_append_after_dash" ]; then
 fi
 
 if "$gem5"; then
-  gem5_build_dir="${buildroot_out_dir}/build/gem5-1.0"
-  gem5_src_dir="${root_dir}/gem5/gem5"
-  gem5_system_dir="${gem5_out_dir}/system"
   memory="${memory}B"
   if [ "$arch" = x86_64 ]; then
     gem5_arch=X86
@@ -170,14 +169,14 @@ if "$gem5"; then
 "
   fi
   gem5_common="\
-M5_PATH='${gem5_system_dir}' \\
+M5_PATH='${common_gem5_system_dir}' \\
 ${debug_vm} \
-'${gem5_out_dir}/build/${gem5_arch}/gem5.opt' \\
+'${common_gem5_build_dir}/${gem5_arch}/gem5.opt' \\
 --debug-file=trace.txt \\
 ${gem5opts} \
--d '${m5out_dir}' \\
-'${gem5_src_dir}/configs/example/fs.py' \\
---disk-image='${images_dir}/rootfs.ext2' \\
+-d '${common_m5out_dir}' \\
+'${common_gem5_src_dir}/configs/example/fs.py' \\
+--disk-image='${common_images_dir}/rootfs.ext2' \\
 --kernel='${common_vmlinux}' \\
 --mem-size='${memory}' \\
 --num-cpus='${cpus}' \\
@@ -197,7 +196,7 @@ ${extra_flags} \
     # Anything smaller than physical blows up as expected, but why can't it auto-detect the right value?
     cmd="${gem5_common} \
 --command-line='earlyprintk=pl011,0x1c090000 console=ttyAMA0 lpj=19988480 rw loglevel=8 mem=${memory} root=/dev/sda ${extra_append}' \\
---dtb-file='${gem5_system_dir}/arm/dt/$([ "$arch" = arm ] && echo "armv7_gem5_v1_${cpus}cpu" || echo "armv8_gem5_v1_${cpus}cpu").dtb' \\
+--dtb-file='${common_gem5_system_dir}/arm/dt/$([ "$arch" = arm ] && echo "armv7_gem5_v1_${cpus}cpu" || echo "armv8_gem5_v1_${cpus}cpu").dtb' \\
 --machine-type=VExpress_GEM5_V1 \\
 ${extra_flags} \
 "
@@ -235,7 +234,7 @@ ${serial_monitor} \
 -virtfs 'local,path=${buildroot_out_dir}/build,mount_tag=host_out,security_model=mapped,id=host_out' \\
 ${vnc}"
   if "$initrd"; then
-    extra_flags="${extra_flags} -initrd '${images_dir}/rootfs.cpio' \\
+    extra_flags="${extra_flags} -initrd '${common_images_dir}/rootfs.cpio' \\
 "
   fi
   if "$ramfs"; then
@@ -243,7 +242,7 @@ ${vnc}"
     root='root=/dev/anything'
   else
     if [ ! "$arch" = mips64 ]; then
-      extra_flags="${extra_flags} -drive 'file=${images_dir}/rootfs.ext2.qcow2,format=qcow2,if=virtio,snapshot' \\
+      extra_flags="${extra_flags} -drive 'file=${common_images_dir}/rootfs.ext2.qcow2,format=qcow2,if=virtio,snapshot' \\
 "
       root='root=/dev/vda'
     fi
@@ -291,14 +290,14 @@ ${qemu_common} \
 -append '${root} ${extra_append}' \\
 -cpu cortex-a57 \\
 -device virtio-gpu-pci \\
--kernel '${images_dir}/Image' \\
+-kernel '${common_images_dir}/Image' \\
 ${extra_flags} \
 "
     ;;
     mips64)
       if ! "$ramfs"; then
         root='root=/dev/hda'
-        extra_flags="${extra_flags} -drive 'file=${images_dir}/rootfs.ext2.qcow2,format=qcow2,snapshot' \\
+        extra_flags="${extra_flags} -drive 'file=${common_images_dir}/rootfs.ext2.qcow2,format=qcow2,snapshot' \\
 "
       fi
       cmd="\