quest-kexec/docs/build.md

Building

There are two kernels involved:

1. Android kernel currently running on the headset. It is used only to build quest_kexec.ko; source, configuration, release suffix and Module.symvers must match the device exactly.
2. Target kernel entered by kexec. It is the Meta Quest Pro kernel with the patches in kernel/patches/ (or branch qkx-kexec in the companion fork).

Android loader ABI tree

For OS build 51503870024400340, use Meta commit fa2e480a85..., copy the headset's /proc/config.gz to the output .config, disable CONFIG_LOCALVERSION_AUTO, and build Image modules with local version -g49638c7a8637. A full module build is required to produce correct symbol CRCs in Module.symvers.

The vendor audio tree needs its pinctrl include directory in KCFLAGS:

SRC=/path/to/meta-kernel-at-fa2e480a85
OUT=/path/to/android-out
adb exec-out 'su -c "zcat /proc/config.gz"' > "$OUT/.config"
$SRC/scripts/config --file "$OUT/.config" --disable LOCALVERSION_AUTO
make -C "$SRC" O="$OUT" ARCH=arm64 CC=clang LD=ld.lld HOSTCC=clang \
  CROSS_COMPILE=aarch64-linux-gnu- CLANG_TRIPLE=aarch64-linux-gnu- \
  LOCALVERSION=-g49638c7a8637 olddefconfig
make -C "$SRC" O="$OUT" ARCH=arm64 CC=clang LD=ld.lld HOSTCC=clang \
  CROSS_COMPILE=aarch64-linux-gnu- CLANG_TRIPLE=aarch64-linux-gnu- \
  LOCALVERSION=-g49638c7a8637 KCFLAGS=-I$SRC/drivers/pinctrl -j8 Image modules
make module KDIR="$OUT" LOCALVERSION=-g49638c7a8637
modinfo -F vermagic module/quest_kexec.ko

The reported vermagic must begin with the output of adb shell uname -r.

Target kernel

Clone YusufOzmen01/oculus-linux-kernel, then check out qkx-kexec. Or apply all patches in order to upstream Quest Pro commit 42dc87a978:

git am /path/to/quest-pro-kexec/kernel/patches/*.patch

Start from the device config and make these configuration changes:

CONFIG_LOCALVERSION_AUTO=n
CONFIG_ION_POOL_AUTO_REFILL=n
CONFIG_USB_CONFIGFS_ECM=y
CONFIG_DEVTMPFS=y
CONFIG_PRINTK_TIME=y
CONFIG_LOG_BUF_SHIFT=20

Build a raw ARM64 Image. The repository's staging layout requires text offset 0x80000, a relocatable little-endian 4 KiB-page image, maximum memory size 0x2f80000, and maximum initramfs/DTB size 2 MiB each.

BusyBox/initramfs

make initramfs

initramfs/busybox.sh downloads BusyBox 1.36.1 from busybox.net, verifies its published SHA-256, then cross-builds it static. initramfs/build.py verifies the binary is static ARM64 and generates deterministic gzip/newc output.