Disable networking at runtime with lkmc_nonet cli instead of build

This is necessary because qemu and gem5 now use the same build folder.

Separate ./run -e and -f for kernel options before and after the ' - '.
This was already the better thing to do when -E was introduced,
but lkmc_nonet prompted me to do it nicer now.

Use the common script to find the out_dir on every toplevel script.

Include usage man pages on README.

README.adoc

@@ -1017,10 +1017,10 @@ but why not just use your super simple and effective `/poweroff.out` and be done
 
 === Run command at the end of BusyBox init
 
-If you rely on something that BusyBox' init set up for you like networking, you caould do:
+If you rely on something that BusyBox' init set up for you like networking, you could do:
 
 ....
-./run -e '- lkmc_eval="insmod /hello.ko;wget -S google.com;poweroff.out;"'
+./run -f 'lkmc_eval="insmod /hello.ko;wget -S google.com;poweroff.out;"'
 ....
 
 The `lkmc_eval` option gets evaled by our default `S98` startup script if present.
@@ -1073,16 +1073,10 @@ Finally, the docs are lying, arguments with dots that come after `-` are still t
 
 The default BusyBox init scripts enable networking, and there is a 15 second timeout in case your network is down or if your kernel / emulator setup does not support it.
 
-To disable networking, use:
+We have hacked it up so that you can disable networking with:
 
 ....
-./build -p -n
+./run -f 'lkmc_nonet=y'
-....
-
-To restore it, run:
-
-....
-./build -- initscripts-reconfigure
 ....
 
 == KVM
@@ -2951,7 +2945,7 @@ which is very close to the end of the boot. Increasing the memory from 256M to 5
 === gem5 limitations
 
 * networking not working. We currently just disable it from `inittab` by default to prevent waiting at startup
-* `gdbserver`: https://stackoverflow.com/questions/48941494/how-to-do-port-forwarding-from-guest-to-host-in-gem5
+* could not do port forwarding from host to guest, and therefore use `gdbserver`: https://stackoverflow.com/questions/48941494/how-to-do-port-forwarding-from-guest-to-host-in-gem5
 
 ==== gem5 x86_64 limitations
 
@@ -2962,7 +2956,6 @@ which is very close to the end of the boot. Increasing the memory from 256M to 5
 [    0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns
 ....
 
-
 == Insane action
 
 === Run on host
@@ -3309,6 +3302,16 @@ include::rootfs_overlay/README.adoc[]
 
 :leveloffset: -3
 
+=== Script man pages
+
+:leveloffset: +3
+
+include::build-usage.adoc[]
+
+include::run-usage.adoc[]
+
+:leveloffset: -3
+
 :leveloffset: +2
 
 include::CONTRIBUTING.adoc[]

br2

@@ -28,6 +28,9 @@ BR2_TOOLCHAIN_BUILDROOT_CXX=y
 BR2_TOOLCHAIN_BUILDROOT_FORTRAN=y
 BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
 
+# We use our own to turn it on and off at runtime.
+BR2_PACKAGE_IFUPDOWN_SCRIPTS=n
+
 # lscpu: TODO not installing?
 BR2_PACKAGE_UTIL_LINUX=y
 BR2_PACKAGE_UTIL_LINUX_BINARIES=y

build

@@ -76,7 +76,7 @@ BR2_TARGET_ROOTFS_INITRAMFS=n
 done
 shift $(($OPTIND - 1))
 extra_make_args="$extra_make_args $@"
-set_common_vars "$arch"
+set_common_vars "$arch" "$gem5"
 case "$arch" in
   x86_64)
     defconfig=qemu_x86_64_defconfig
@@ -91,9 +91,7 @@ case "$arch" in
     defconfig=qemu_mips64r6_malta_defconfig
   ;;
 esac
-if "$gem5"; then
+if ! "$gem5"; then
-  post_script_args="$post_script_args -n"
-else
   config_fragments="$config_fragments br2_qemu"
 fi
 config_fragments="$config_fragments br2_cli.gitignore"

common

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set_common_vars() {
   arch="$1"
+  gem5="$2"
   root_dir="$(pwd)"
   buildroot_dir="${root_dir}/buildroot"
   arch_dir="$arch"

count-boot-instructions

@@ -1,7 +1,17 @@
 #!/usr/bin/env bash
-set -e
+set -eu
-time ./run -n -e 'init=/poweroff.out' -- -trace exec_tb,file=trace
+. common
-time ./qemu/scripts/simpletrace.py buildroot/output.x86_64~/build/host-qemu-custom/trace-events-all trace >trace.txt
+arch=x86_64
+while getopts a: OPT; do
+  case "$OPT" in
+    a)
+      arch="$OPTARG"
+      ;;
+  esac
+done
+set_common_vars "$arch" false
+time ./run -a "$arch" -n -e 'init=/poweroff.out' -- -trace exec_tb,file=trace
+time ./qemu/scripts/simpletrace.py "${out_dir}/build/host-qemu-custom/trace-events-all" trace >trace.txt
 wc -l trace.txt
 sed '/0x1000000/q' trace.txt >trace-boot.txt
 wc -l trace-boot.txt

rootfs_overlay/etc/init.d/S40network

@@ -0,0 +1,44 @@
+#!/bin/sh
+
+# Copied from: package/ifupdown-scripts/S40network at
+# 8ce27bb9fee80a406a4199657ef90e3c315e7457
+#
+# We then just added this line to turn it off at runtime.
+#
+# We also considered copying the file at build to / and then
+# sourcing it from S98 to be a bit DRYer, but it wouldn't work
+# very well if some S50 requires networking to work.
+#
+# This became necessary nitially when aarch64 qemu and gem5
+# started using the same Buildroot output directory.
+[ -n "$lkmc_nonet" ] && exit 0
+
+#
+# Start the network....
+#
+
+# Debian ifupdown needs the /run/network lock directory
+mkdir -p /run/network
+
+case "$1" in
+  start)
+	printf "Starting network: "
+	/sbin/ifup -a
+	[ $? = 0 ] && echo "OK" || echo "FAIL"
+	;;
+  stop)
+	printf "Stopping network: "
+	/sbin/ifdown -a
+	[ $? = 0 ] && echo "OK" || echo "FAIL"
+	;;
+  restart|reload)
+	"$0" stop
+	"$0" start
+	;;
+  *)
+	echo "Usage: $0 {start|stop|restart}"
+	exit 1
+esac
+
+exit $?
+

rootfs_post_build_script

@@ -5,19 +5,6 @@
 # To test it out, arguments can be passed with:
 #     make BR2_ROOTFS_POST_SCRIPT_ARGS="asdf qwer"
 target_dir="$1"
-shift
-net=true
-while getopts 'n' OPT; do
-  case "$OPT" in
-    n)
-      net=false
-    ;;
-  esac
-done
-shift $(($OPTIND - 1))
-if ! "$net"; then
-  rm -f "${target_dir}/etc/init.d/"S*network
-fi
 mkdir -p \
   "${target_dir}/mnt/9p" \
   "${target_dir}/mnt/out" \

run

@@ -13,6 +13,7 @@ kvm=false
 # nokaslr: https://unix.stackexchange.com/questions/397939/turning-off-kaslr-to-debug-linux-kernel-using-qemu-and-gdb
 #   Turned on by default since v4.12
 extra_append='nokaslr norandmaps printk.devkmsg=on printk.time=y'
+extra_append_after_dash=''
 extra_flags=''
 extra_flags_qemu=''
 gem5=false
@@ -23,7 +24,7 @@ initramfs=false
 memory=256M
 nographic=false
 root=''
-while getopts a:c:DdE:e:G:gIiKkm:nt:x OPT; do
+while getopts a:c:DdE:e:f:G:gIiKkm:nt:x OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
@@ -43,6 +44,9 @@ while getopts a:c:DdE:e:G:gIiKkm:nt:x OPT; do
     e)
       extra_append="$extra_append $OPTARG"
       ;;
+    f)
+      extra_append_after_dash="$extra_append_after_dash $OPTARG"
+      ;;
     K)
       kvm=true
       ;;
@@ -79,7 +83,7 @@ while getopts a:c:DdE:e:G:gIiKkm:nt:x OPT; do
 done
 shift "$(($OPTIND - 1))"
 extra_flags="$extra_flags $@"
-set_common_vars "$arch"
+set_common_vars "$arch" "$gem5"
 if "$initrd" || "$initramfs"; then
   ramfs=true
 else
@@ -91,12 +95,19 @@ if [ -n "$lkmc_eval" ]; then
   else
     initarg="init"
   fi
-  extra_append="${extra_append} ${initarg}=/eval_base64.sh - lkmc_eval=\"$(printf "$lkmc_eval" | base64)\""
+  extra_append="${extra_append} ${initarg}=/eval_base64.sh"
+  extra_append_after_dash="${extra_append_after_dash} lkmc_eval=\"$(printf "$lkmc_eval" | base64)\""
 fi
 if "$nographic" && [ "$arch" = x86_64 ]; then
   extra_append="$extra_append console=ttyS0"
   extra_flags_qemu="$extra_flags_qemu -nographic"
 fi
+if "$gem5"; then
+  extra_append_after_dash="${extra_append_after_dash} lkmc_nonet=y"
+fi
+if [ -n "$extra_append_after_dash" ]; then
+  extra_append="${extra_append} - ${extra_append_after_dash}"
+fi
 
 if "$gem5"; then
   build_dir="${out_dir}/build/gem5-1.0"
@@ -125,15 +136,16 @@ ${gem5opts} \
     if "$kvm"; then
       extra_flags="$extra_flags --cpu-type=X86KvmCPU"
     fi
-    cmd="${gem5_common} \
+    cmd="\
---command-line='earlyprintk=ttyS0 console=ttyS0 lpj=7999923 root=/dev/hda $extra_append' \
+${gem5_common} \
-$extra_flags \
+--command-line='earlyprintk=ttyS0 console=ttyS0 lpj=7999923 root=/dev/hda ${extra_append}' \
+${extra_flags} \
 "
   elif [ "$arch" = arm ] || [ "$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 $extra_append' \
+--command-line='earlyprintk=pl011,0x1c090000 console=ttyAMA0 lpj=19988480 rw loglevel=8 mem=${memory} root=/dev/sda ${extra_append}' \
 --dtb-file='${gem5_dir}/system/arm/dt/$([ "$arch" = arm ] && echo "armv7_gem5_v1_${cpus}cpu" || echo "armv8_gem5_v1_${cpus}cpu").dtb' \
 --machine-type=VExpress_GEM5_V1 \
 ${extra_flags} \
@@ -157,19 +169,22 @@ ${debug_vm} \
   if "$initrd"; then
     extra_flags="${extra_flags} -initrd '${images_dir}/rootfs.cpio'"
   fi
+  if "$ramfs"; then
+    # TODO why is this needed, and why any string works.
+    root='root=/dev/anything'
+  fi
   # The base QEMU commands are found under board/qemu/*/readme.tx
   case "$arch" in
     x86_64)
       if "$kgdb"; then
         extra_append="${extra_append} kgdboc=ttyS0,115200"
       fi
-      if "$ramfs"; then
+      if ! "$ramfs"; then
-        root='root=/dev/anything'
-      else
         root='root=/dev/vda'
         extra_flags="${extra_flags} -drive file='${images_dir}/rootfs.ext2.qcow2,if=virtio,format=qcow2'"
       fi
-      cmd="${qemu_common} \
+      cmd="\
+${qemu_common} \
 -M pc \
 -append '${root} nopat ${extra_append}' \
 -device edu \
@@ -183,13 +198,12 @@ ${extra_flags} \
       if "$kgdb"; then
         extra_append="${extra_append} kgdboc=ttyAMA0,115200"
       fi
-      if "$ramfs"; then
+      if ! "$ramfs"; then
-        root='root=/dev/anything'
-      else
         extra_flags="${extra_flags} -drive file='${images_dir}/rootfs.ext2.qcow2,if=scsi,format=qcow2'"
         root='root=/dev/sda'
       fi
-      cmd="$qemu_common \
+      cmd="\
+$qemu_common \
 -M versatilepb \
 -append '${root} ${extra_append}' \
 -device rtl8139,netdev=net0 \
@@ -203,13 +217,12 @@ $extra_flags \
       if "$kgdb"; then
         extra_append="${extra_append} kgdboc=ttyAMA0,115200"
       fi
-      if "$ramfs"; then
+      if ! "$ramfs"; then
-        root='root=/dev/anything'
-      else
         root='root=/dev/vda'
         extra_flags="${extra_flags} -drive file='${images_dir}/rootfs.ext2.qcow2,if=virtio,format=qcow2'"
       fi
-      cmd="${qemu_common} \
+      cmd="\
+${qemu_common} \
 -M virt \
 -append '${root} ${extra_append}' \
 -cpu cortex-a57 \
@@ -221,13 +234,12 @@ ${extra_flags} \
 "
     ;;
     mips64)
-      if "$ramfs"; then
+      if ! "$ramfs"; then
-        root='root=/dev/anything'
-      else
         root='root=/dev/hda'
         extra_flags="${extra_flags} -drive file='${images_dir}/rootfs.ext2.qcow2,format=qcow2'"
       fi
-      cmd="${qemu_common} \
+      cmd="\
+${qemu_common} \
 -M malta \
 -append '${root} ${extra_append}' \
 -cpu I6400 \

run-usage.adoc

@@ -14,8 +14,17 @@
 |`-E` |`CMDSTR`             | Replace the normal init with a minimal init that just evals
                               with given `CMDSTR` bash command string. Example:
                               `-E 'insmod /hello.ko;'`
-|`-e` |`CLI_OPTIONS`        | Pass an extra Linux kernel command line options.
+|`-e` |`CLI_OPTIONS`        | Pass an extra Linux kernel command line options,
+                              and place them before the dash separator `-`.
+                              Only options that come before the `-`, i.e. "standard"
+                              options, should be passed with this option.
                               Example: `./run -a arm -e 'init=/poweroff.out'`
+|`-f` |`CLI_OPTIONS`        | Pass an extra Linux kernel command line options,
+                              add a dash `-` separator, and place the options after the dash.
+                              Intended for custom options understood by our `init` scripts,
+                              most of which are prefixed by `lkmc_`, e.g.:
+                              `./run -f 'lkmc_eval="wget google.com" lkmc_nonet=y'`
+                              Mnenomic: comes after `-e`.
 |`-K` |                     | Use KVM. Only works if guest arch == host arch.
 |`-k` |                     | Enable KGDB.
 |`-G` |                     | Pass extra options to the gem5 executable.

rungdb

@@ -1,7 +1,6 @@
 #!/usr/bin/env bash
-
+set -eu
-set -e
+. common
-
 arch='x86_64'
 bdfore=''
 gem5=false
@@ -39,17 +38,16 @@ else
   arch_dir="$arch"
   port=1234
 fi
-
+set_common_vars "$arch" "$gem5"
-buildroot_out_dir="$(pwd)/buildroot/output.${arch_dir}~"
+gdb="${out_dir}/host/usr/bin/${arch}-linux-gdb $before"
-gdb="${buildroot_out_dir}/host/usr/bin/${arch}-linux-gdb $before"
+cd "${out_dir}/build/linux-custom/"
-cd "${buildroot_out_dir}/build/linux-custom/"
 if "$kgdb"; then
     cmd="$gdb \
-      -q \
+-q \
-      -ex 'add-auto-load-safe-path $(pwd)' \
+-ex 'add-auto-load-safe-path $(pwd)' \
-      -ex 'file vmlinux' \
+-ex 'file vmlinux' \
-      -ex 'target remote localhost:$port'
+-ex 'target remote localhost:$port'
-    "
+"
 else
   case "$arch" in
     'x86_64')

rungdb-user

@@ -1,12 +1,17 @@
 #!/usr/bin/env bash
-set -e
+set -eu
+. common
 usage="$0 <exec-relative-path> [<brk-symbol>]"
 arch='x86_64'
-while getopts a:h OPT; do
+gem5=false
+while getopts a:gh OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
       ;;
+    g)
+      gem5=true
+      ;;
     h)
       echo "$usage"
       exit 0
@@ -22,9 +27,9 @@ if [ "$#" -gt 0 ]; then
 else
   brk=''
 fi
-buildroot_out_dir="$(pwd)/buildroot/output.${arch}~"
+set_common_vars "$arch" "$gem5"
-executable="${buildroot_out_dir}/build/${executable_rel}"
+executable="${out_dir}/build/${executable_rel}"
-readelf="${buildroot_out_dir}/host/usr/bin/${arch}-linux-readelf"
+readelf="${out_dir}/host/usr/bin/${arch}-linux-readelf"
 addr="$("$readelf" -h "$executable" | awk '/Entry/{ print $NF }' )"
 ex="-ex \"add-symbol-file $executable $addr\""
 # Twice because lx-symbols overrides our add-symbol-file commands.

rungdbserver

@@ -1,20 +1,26 @@
-#!/bin/sh
+#!/usr/bin/env bash
+set -eu
+. common
 arch='x86_64'
-while getopts a:k OPT; do
+gem5=false
+while getopts a:g OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
       ;;
+    g)
+      gem5=true
+      ;;
   esac
 done
 shift "$(($OPTIND - 1))"
 executable="$1"
-buildroot_out_dir="$(pwd)/buildroot/output.${arch}~"
+set_common_vars "$arch" "$gem5"
-"${buildroot_out_dir}/host/usr/bin/${arch}-linux-gdb" \
+"${out_dir}/host/usr/bin/${arch}-linux-gdb" \
-    -q \
+  -q \
-    -ex "set sysroot ${buildroot_out_dir}/staging" \
+  -ex "set sysroot ${out_dir}/staging" \
-    -ex 'target remote localhost:45455' \
+  -ex 'target remote localhost:45455' \
-    -ex 'tb main' \
+  -ex 'tb main' \
-    -ex 'c' \
+  -ex 'c' \
-    "${buildroot_out_dir}/build/${executable}" \
+  "${out_dir}/build/${executable}" \
 ;