build: separate generic ARM64 from Raspberry Pi kernel builds

Splits the ARM64 build into two tracks per docs/arm64-architecture.md:

Generic ARM64 (mainline kernel.org, UEFI, virtio, GRUB):
- New build/scripts/build-kernel-arm64.sh builds mainline LTS (6.12.x by default)
  from arm64 defconfig + shared container fragment + arm64-virt enables
  (VIRTIO_*, EFI_STUB, NVMe). Output: build/cache/kernel-arm64-generic/.
- New Makefile targets: kernel-arm64, rootfs-arm64 (now consumes the mainline
  kernel modules via TARGET_VARIANT=generic).
- versions.env: pin MAINLINE_KERNEL_VERSION=6.12.10, declare cdn.kernel.org URL
  and SHA256 placeholder.

Raspberry Pi (raspberrypi/linux fork, custom DTBs, autoboot.txt):
- build-kernel-arm64.sh (RPi-flavoured) renamed to build-kernel-rpi.sh; cache
  dir renamed from custom-kernel-arm64 to custom-kernel-rpi.
- New Makefile targets: kernel-rpi, rootfs-arm64-rpi (uses TARGET_VARIANT=rpi).
- rpi-image now depends on rootfs-arm64-rpi + kernel-rpi instead of the generic
  rootfs-arm64.
- create-rpi-image.sh + inject-kubesolo.sh updated to reference the new cache
  path. inject-kubesolo.sh now takes a TARGET_VARIANT env var (rpi|generic) to
  select which ARM64 kernel modules to consume.

Shared substrate:
- rpi-kernel-config.fragment renamed to kernel-container.fragment. The contents
  were never RPi-specific (cgroup, namespaces, AppArmor, netfilter) — just
  misnamed. Extended with extra subsystem disables (KVM, WLAN, CFG80211,
  INFINIBAND, PCMCIA, HAMRADIO, ISDN, ATM, INPUT_JOYSTICK, INPUT_TABLET, FPGA)
  and CONFIG_LSM=lockdown,yama,apparmor.
- build-kernel.sh (x86) refactored to apply the shared fragment via a generic
  apply_fragment function (two-pass for the TC stock config security dance),
  killing ~50 lines of inline config duplication.

Note: rename detection shows build-kernel-arm64.sh as 'modified' because the
new file at that path is the mainline build, while the old RPi-flavoured
content lives in build-kernel-rpi.sh (which appears as a new file). The git
log for build-kernel-rpi.sh is empty; the RPi history is preserved at the
original path until this commit.

No actual kernel build runs in this commit — that's Phase 3 work.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-14 10:30:11 -06:00
parent 19b99cf101
commit d51618badb
8 changed files with 402 additions and 169 deletions

View File

@@ -85,85 +85,49 @@ echo " Source dir: $(basename "$KERNEL_SRC_DIR")"
cd "$KERNEL_SRC_DIR"
# --- Apply stock config + enable CONFIG_CGROUP_BPF ---
# --- Apply stock config + shared container-config fragment ---
echo "==> Applying stock Tiny Core config..."
cp "$KERNEL_CFG" .config
echo "==> Enabling required kernel configs..."
./scripts/config --enable CONFIG_CGROUP_BPF
./scripts/config --enable CONFIG_DEVTMPFS
./scripts/config --enable CONFIG_DEVTMPFS_MOUNT
./scripts/config --enable CONFIG_MEMCG
./scripts/config --enable CONFIG_CFS_BANDWIDTH
CONFIG_FRAGMENT="$PROJECT_ROOT/build/config/kernel-container.fragment"
if [ ! -f "$CONFIG_FRAGMENT" ]; then
echo "ERROR: Config fragment not found: $CONFIG_FRAGMENT"
exit 1
fi
# --- Strip unnecessary subsystems for smallest footprint ---
# This is a headless K8s edge appliance — no sound, GPU, wireless, etc.
echo "==> Disabling unnecessary subsystems for minimal footprint..."
# Apply the fragment: each "CONFIG_X=v" line becomes the right scripts/config
# invocation; "# CONFIG_X is not set" comments become --disable.
apply_fragment() {
local fragment="$1"
while IFS= read -r line; do
case "$line" in
"# CONFIG_"*" is not set")
key=$(echo "$line" | sed -n 's/^# \(CONFIG_[A-Z0-9_]*\) is not set$/\1/p')
[ -n "$key" ] && ./scripts/config --disable "${key#CONFIG_}"
continue
;;
\#*|"") continue ;;
esac
key="${line%%=*}"
value="${line#*=}"
case "$value" in
y) ./scripts/config --enable "$key" ;;
m) ./scripts/config --module "$key" ;;
n) ./scripts/config --disable "${key#CONFIG_}" ;;
*) ./scripts/config --set-str "$key" "$value" ;;
esac
done < "$fragment"
}
# Sound subsystem (not needed on headless appliance)
./scripts/config --disable SOUND
# GPU/DRM (serial console only, no display)
./scripts/config --disable DRM
# KVM hypervisor (this IS the guest/bare metal, not a hypervisor)
./scripts/config --disable KVM
# Media/camera/TV/radio (not needed)
./scripts/config --disable MEDIA_SUPPORT
# Wireless networking (wired edge device)
./scripts/config --disable WIRELESS
./scripts/config --disable WLAN
./scripts/config --disable CFG80211
# Bluetooth (not needed)
./scripts/config --disable BT
# NFC (not needed)
./scripts/config --disable NFC
# Infiniband (not needed on edge)
./scripts/config --disable INFINIBAND
# PCMCIA (legacy, not needed)
./scripts/config --disable PCMCIA
# Amateur radio (not needed)
./scripts/config --disable HAMRADIO
# ISDN (not needed)
./scripts/config --disable ISDN
# ATM networking (not needed)
./scripts/config --disable ATM
# Joystick/gamepad (not needed)
./scripts/config --disable INPUT_JOYSTICK
./scripts/config --disable INPUT_TABLET
# FPGA (not needed)
./scripts/config --disable FPGA
# First pass: resolve base dependencies before adding security configs.
# The stock TC config has "# CONFIG_SECURITY is not set" which causes
# olddefconfig to strip security-related options if applied in a single pass.
# Two-pass apply: TC's stock config has CONFIG_SECURITY disabled, so olddefconfig
# strips the security subtree before its dependencies resolve. Re-applying the
# fragment after the first olddefconfig restores those entries.
echo "==> Applying kernel-container.fragment (pass 1)..."
apply_fragment "$CONFIG_FRAGMENT"
make olddefconfig
# Security: AppArmor LSM + Audit subsystem
# Applied AFTER first olddefconfig to ensure CONFIG_SECURITY dependencies
# (SYSFS, MULTIUSER) are resolved before enabling the security subtree.
echo "==> Enabling AppArmor + Audit kernel configs..."
./scripts/config --enable CONFIG_AUDIT
./scripts/config --enable CONFIG_AUDITSYSCALL
./scripts/config --enable CONFIG_SECURITY
./scripts/config --enable CONFIG_SECURITYFS
./scripts/config --enable CONFIG_SECURITY_NETWORK
./scripts/config --enable CONFIG_SECURITY_APPARMOR
./scripts/config --set-str CONFIG_LSM "lockdown,yama,apparmor"
./scripts/config --set-str CONFIG_DEFAULT_SECURITY "apparmor"
# Second pass: resolve security config dependencies
echo "==> Applying kernel-container.fragment (pass 2)..."
apply_fragment "$CONFIG_FRAGMENT"
make olddefconfig
# Verify critical configs are set