gem5: integrate fs_bigLITTLE.py into run

README.adoc

@@ -6390,9 +6390,9 @@ The out of build tree is required, because otherwise Buildroot would copy the ou
 
 === gem5 fs_bigLITTLE
 
-TODO integrate into `run`. There is no way to pass command line arguments except by hacking the script, this is a pre-requisite for good integration.
+By default, we use `configs/example/fs.py` script.
 
-This system is more representative of ARM, which almost always has the big little cluster.
+The `-X-b` option enables the alternative `configs/example/arm/fs_bigLITTLE.py` script instead.
 
 First apply:
 
@@ -6418,14 +6418,20 @@ index 7d66c03a6..d71e714fe 100644
 then:
 
 ....
-./fs-biglittle
+./run -aA -g -X-b
 ....
 
-Source: link:fs-biglittle[]
+Advantages over `fs.py`:
 
-Boot messages start at 5 minutes, boot finishes at 10 minutes and gives a shell.
+* more representative of mobile ARM SoCs, which almost always have  big little cluster
+* simpler than `fs.py`, and therefore easier to understand and modify
 
-`cat /proc/cpuinfo` shows 4 identical CPUs instead of 2 of two different types, likely because gem5 does not expose some informational register much like the caches: https://www.mail-archive.com/gem5-users@gem5.org/msg15426.html `config.ini` does show that the two big ones are `DerivO3CPU` and the small ones are `MinorCPU`.
+Disadvantages over `fs.py`:
+
+* only works for ARM, not other archs
+* not as many configuration options as `fs.py`, many things are hardcoded
+
+We setup 2 big and 2 small CPUs, but `cat /proc/cpuinfo` shows 4 identical CPUs instead of 2 of two different types, likely because gem5 does not expose some informational register much like the caches: https://www.mail-archive.com/gem5-users@gem5.org/msg15426.html `config.ini` does show that the two big ones are `DerivO3CPU` and the small ones are `MinorCPU`.
 
 TODO: why is the `--dtb` required despite `fs_bigLITTLE.py` having a DTB generation capability? Without it, nothing shows on terminal, and the simulation terminates with `simulate() limit reached  @  18446744073709551615`. The magic `vmlinux.vexpress_gem5_v1.20170616` works however without a DTB.
 

fs-biglittle

@@ -1,13 +0,0 @@
-#!/usr/bin/env bash
-. common
-set_common_vars -L "${common_linux_variant}" -M "${common_gem5_variant}" aarch64 true
-M5_PATH="${common_gem5_system_dir}" \
-  "${common_gem5_build_dir}/ARM/gem5.opt" \
-  "${common_gem5_default_src_dir}/configs/example/arm/fs_bigLITTLE.py" \
-  --big-cpus=2 \
-  --caches \
-  --disk="${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 \
-;

run

@@ -18,8 +18,10 @@ extra_append='console_msg_format=syslog nokaslr norandmaps printk.devkmsg=on pri
 extra_append_after_dash=
 extra_flags=
 extra_flags_qemu=
+extra_opts=
 gem5=false
 gem5opts=
+gem5_fsbiglittle=false
 lkmc_eval=
 initrd=false
 initramfs=false
@@ -34,7 +36,7 @@ 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:m:n:PT:U:uVx OPT; do
+while getopts a:c:DdE:e:F:f:G:ghIiKkL:M:m:n:PT:U:uVX:x OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
@@ -114,6 +116,9 @@ while getopts a:c:DdE:e:F:f:G:ghIiKkL:M:m:n:PT:U:uVx OPT; do
     u)
       tmux=true
       ;;
+    X)
+      extra_opts="${extra_opts} ${OPTARG}"
+      ;;
     x)
       nographic=false
       ;;
@@ -128,6 +133,17 @@ while getopts a:c:DdE:e:F:f:G:ghIiKkL:M:m:n:PT:U:uVx OPT; do
 done
 shift "$(($OPTIND - 1))"
 extra_flags="$extra_flags $@"
+OPTIND=1
+while getopts b OPT "$extra_opts"; do
+  case "$OPT" in
+    b)
+      gem5_fsbiglittle=true
+      ;;
+    ?)
+      exit 2
+      ;;
+  esac
+done
 set_common_vars -L "$common_linux_variant" -M "$common_gem5_variant" -n "$common_run_id" "$arch" "$gem5"
 if "$debug" && "$kvm"; then
   echo 'error: -d and -K are incompatible' 1>&2
@@ -176,6 +192,21 @@ ${debug_vm} \
 --debug-file=trace.txt \\
 ${gem5opts} \
 -d '${common_m5out_dir}' \\
+"
+  if "$gem5_fsbiglittle"; then
+      cmd="${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 \\
+${extra_flags} \\
+"
+  else
+    gem5_common="\
+${gem5_common} \
 '${common_gem5_src_dir}/configs/example/fs.py' \\
 --disk-image='${common_images_dir}/rootfs.ext2' \\
 --kernel='${common_vmlinux}' \\
@@ -202,6 +233,7 @@ ${extra_flags} \
 ${extra_flags} \
 "
     fi
+  fi
 else
   mkdir -p "$common_qemu_run_dir"
   if [ -z "$debug_vm" ]; then

run-usage.adoc

@@ -58,5 +58,10 @@
                         ** if on gem5, the gem5 terminal
 |`-V`   |              |Run QEMU with VNC instead of the default SDL.
                         Connect to it with: `vinagre localhost:5900`.
+|`-X`   |`EXTRA_OPTS`  |Extra options that did not fit into `A-z`!
+                        This string is parsed by `getopt` on a separate parse step with different
+                        meanings for each flag.
+|`-X-b` |              |Use `fs_bigLITTLE.py` instead of `fs.py` on gem5 simulation.
+                       Ignored by QEMU.
 |`-x`   |              |Run in graphic mode. Mnemonic: X11.
 |===