From 4ae045d72d710a25ecdbe2c71499ac05f7bcfa47 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Wed, 28 Sep 2022 07:03:59 +0200
Subject: Add support for --arch-variant, --kernel-source

---
 bootstrap     | 120 ++++++++++++++++++++++++++++++++++++++++++----------------
 bootstrap.txt |   7 +++-
 buildos       |  10 ++++-
 3 files changed, 103 insertions(+), 34 deletions(-)

diff --git a/bootstrap b/bootstrap
index 773b379..5d560b7 100755
--- a/bootstrap
+++ b/bootstrap
@@ -28,8 +28,22 @@
 #   5 - create footfs
 #   6 - create kernel image and initrd
 #
+# --arch-variant
+#   Architecture variant, for example, m1 for aarch64-m1.
+#
+# --kernel-source
+#   Pre-configured Linux kernel source .tar.* archive. If unspecified, Debian
+#   source/configuration will be used.
+#
 usage="usage: $0"
 
+owd="$(pwd)"
+trap "{ cd '$owd'; exit 1; }" ERR
+set -o errtrace # Trap in functions.
+
+function info () { echo "$*" 1>&2; }
+function error () { info "$*"; exit 1; }
+
 id="$(id -un)"
 btrfs=/btrfs
 root="$btrfs/$id/buildos"
@@ -98,15 +112,12 @@ esac
 
 extra_pkgs=""
 
-owd="$(pwd)"
-trap "{ cd '$owd'; exit 1; }" ERR
-set -o errtrace # Trap in functions.
-
-function info () { echo "$*" 1>&2; }
-function error () { info "$*"; exit 1; }
-
-stage="1"
-stage_max="6"
+# Options.
+#
+stage=1
+stage_max=6
+arch_variant=
+kernel_source=
 
 while [ "$#" -gt 0 ]; do
   case "$1" in
@@ -115,6 +126,16 @@ while [ "$#" -gt 0 ]; do
       stage="$1"
       shift
       ;;
+    --arch-variant)
+      shift
+      arch_variant="$1"
+      shift
+      ;;
+    --kernel-source)
+      shift
+      kernel_source="$1"
+      shift
+      ;;
     -*)
       error "unknown option: $1"
       ;;
@@ -128,6 +149,11 @@ if [ "$stage" -lt "1" -o "$stage" -gt "$stage_max" ]; then
   error "invalid stage number $stage"
 fi
 
+arch_with_variant="$arch"
+if [ -n "$arch_variant" ]; then
+  arch_with_variant="$arch_with_variant-$arch_variant"
+fi
+
 # Extract version.
 #
 version="$(sed -n -re 's/^version: ([0-9]+\.[0-9]+\.[0-9]+).*$/\1/p' ./manifest)"
@@ -410,6 +436,12 @@ EOF
   subvol_delete "$root-3-kernel"
   subvol_snapshot "$root" "$root-3-kernel"
 
+  # Copy custom kernel source.
+  #
+  if [ -n "$kernel_source" ]; then
+    sudo install -m 644 "$kernel_source" "$root-3-kernel/usr/src/"
+  fi
+
   # Copy patches.
   #
   #sudo cp ./patches/tftp-hpa-partial-upload.patch "$root-3-kernel/bootstrap/"
@@ -450,20 +482,33 @@ fi
 # kernel with adjusted configuration. Taken from the Debian Kernel Handbook.
 #
 apt-get update
-apt-get install -y linux-source
+apt-get install -y bc
 apt-get install -y bison flex
 apt-get install -y libelf-dev
 apt-get install -y libssl-dev
-apt-get install -y rsync
+apt-get install -y cpio rsync
 apt-get install -y dwarves
+apt-get install -y device-tree-compiler
+
 cd /usr/src
-tar xf linux-source-*
-mv linux-source-*/ linux
-xzcat linux-config-*/config.${debian_arch}_none_${debian_arch}.xz >linux/.config
+
+if [ -z "$kernel_source" ]; then
+  apt-get install -y linux-source
+  tar xf linux-source-*
+  mv linux-source-*/ linux
+  xzcat linux-config-*/config.${debian_arch}_none_${debian_arch}.xz >linux/.config
+else
+  kernel_source=\$(basename $kernel_source)
+  tar xf \$kernel_source
+  mv \$(sed -re 's/(.+)\.tar\..+/\1/' <<<\$kernel_source) linux
+fi
+
 cd linux
 
 # Adjust configuration.
 #
+# Note that we do some of these even for the pre-configured kernel.
+#
 # Note that SECURITY_LOCKDOWN_LSM forces MODULE_SIG ('select' in Kconfig).
 #
 # Generally, if you disable an option but it still appears enabled after
@@ -487,25 +532,30 @@ scripts/config --disable DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
 #
 scripts/config --disable KCOV
 scripts/config --disable SHADOW_CALL_STACK
+scripts/config --disable ZERO_CALL_USED_REGS
 scripts/config --disable VIDEO_ADV7511
 
-# Disable sound subsystem/drivers.
-#
-sed -i -re '/^CONFIG_SND_.+/d' .config
-sed -i -re '/^CONFIG_SOUND_.+/d' .config
-scripts/config --disable CONFIG_SOUND
-scripts/config --disable CONFIG_SND
+if [ -z "$kernel_source" ]; then
 
-# Disable GPU subsystem/drivers.
-#
-# NOTE: this seems to have killed the high-resolution console.
-#
-sed -i -re '/^CONFIG_DRM_.+/d' .config
-scripts/config --disable CONFIG_DRM
+  # Disable sound subsystem/drivers.
+  #
+  sed -i -re '/^CONFIG_SND_.+/d' .config
+  sed -i -re '/^CONFIG_SOUND_.+/d' .config
+  scripts/config --disable CONFIG_SOUND
+  scripts/config --disable CONFIG_SND
 
-# Disable wireless network drivers.
-#
-scripts/config --disable CONFIG_WLAN
+  # Disable GPU subsystem/drivers.
+  #
+  # NOTE: this seems to have killed the high-resolution console.
+  #
+  sed -i -re '/^CONFIG_DRM_.+/d' .config
+  scripts/config --disable CONFIG_DRM
+
+  # Disable wireless network drivers.
+  #
+  scripts/config --disable CONFIG_WLAN
+
+fi
 
 # Adjust kernel command line size limit.
 #
@@ -690,6 +740,11 @@ if [ "$stage" -le "6" ]; then
   sudo ln -sf "$root/usr/lib/systemd/system/buildos.service" \
     "$root/etc/systemd/system/multi-user.target.wants/buildos.service"
 
+  # Patch in the arch variant.
+  #
+  sudo sed -i -e "s/^arch_variant=.*/arch_variant=$arch_variant/" \
+    "$root/usr/sbin/buildos"
+
   info "generating buildos-init.cpio.xz..."
 
   cd "$root"
@@ -703,12 +758,13 @@ etc/systemd/system/multi-user.target.wants/buildos.service
 EOF
   cd "$owd"
 
-  cat buildos-rootfs.cpio.xz buildos-init.cpio.xz >"buildos-initrd-$arch"
+  cat buildos-rootfs.cpio.xz \
+      buildos-init.cpio.xz >"buildos-initrd-$arch_with_variant"
 
   # Copy the kernel image next to the initramfs for convenience.
   #
-  cp "$root/vmlinuz" "buildos-image-$arch"
-  echo "$buildid" >"buildos-buildid-$arch"
+  cp "$root/vmlinuz" "buildos-image-$arch_with_variant"
+  echo "$buildid" >"buildos-buildid-$arch_with_variant"
 
   subvol_snapshot -r "$root" "$root-6"
 fi
diff --git a/bootstrap.txt b/bootstrap.txt
index e9963fa..d02088a 100644
--- a/bootstrap.txt
+++ b/bootstrap.txt
@@ -53,8 +53,13 @@
   Save the log for later comparison (might have to redo a from-stage-1
   bootstrap to get the complete log).
 
+  To bootstrap an architecture variant with a pre-configured kernel:
+
+  ./bootstrap --arch-variant m1 --kernel-source .../linux-asahi-5.19-5-1.tar.xz
+
 * Compare sizes to previous version for any abnormalities (if a lot larger,
-  check if GCC executables are stripped).
+  check if GCC executables are stripped or if the kernel is somewhy is now
+  built with debug info).
 
 * After deployment, test VM upload/removal scripts (there are often issues
   after upgrading to new btrfs-progs).
diff --git a/buildos b/buildos
index 221e781..9808719 100755
--- a/buildos
+++ b/buildos
@@ -29,7 +29,15 @@ function error ()
   exit 1
 }
 
+# Note: the arch variant is patched in by the bootstrap script.
+#
 arch="$(uname -m)"
+arch_variant=
+
+arch_with_variant="$arch"
+if [ -n "$arch_variant" ]; then
+  arch_with_variant="$arch_with_variant-$arch_variant"
+fi
 
 # Network timeouts: 60 seconds to connect, 10 minutes to complete, 4 retries
 # (5 attempts total). These are similar to bbot timeouts. Note that the
@@ -125,7 +133,7 @@ function restart ()
 }
 
 if [ -n "$buildid_url" ]; then
-  buildid_url="$buildid_url-$arch"
+  buildid_url="$buildid_url-$arch_with_variant"
 else
   info "no buildos.buildid_url specified, not monitoring for new os builds"
 fi
-- 
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