quest-kexec/HOW_TO_BUILD.md

Build guide

This project currently has tested settings only for Meta Quest Pro.

Two kernel trees are used:

1. The Android kernel tree builds quest_kexec.ko for the kernel currently running on the headset.
2. The target kernel tree builds the custom kernel entered by kexec.

Requirements

Install:

• Clang and LLD
• aarch64-linux-gnu- GCC/binutils
• adb
• Python 3
• dtc and fdtput
• curl, make and standard build tools

Android kernel and loader module

Check the running version:

adb shell uname -r

Use matching source and save the device config:

mkdir -p android-out
adb exec-out 'su -c "zcat /proc/config.gz"' > android-out/.config

For the tested Quest Pro release, the source commit is:

fa2e480a85c6adbcc73dfc4f0ab0728781e14584

Build the kernel and modules so that Module.symvers contains the correct symbol CRCs:

SRC=/path/to/android-kernel-source
OUT=$PWD/android-out
LOCAL=-g49638c7a8637

$SRC/scripts/config --file "$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="$LOCAL" 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="$LOCAL" KCFLAGS=-I$SRC/drivers/pinctrl \
  -j"$(nproc)" Image modules

Build the kexec and log modules:

make module KDIR="$OUT" LOCALVERSION="$LOCAL"

Verify the result:

modinfo -F vermagic module/quest_kexec.ko
adb shell uname -r

The release strings must match.

Target kernel

For the tested Quest Pro kernel:

git clone https://github.com/YusufOzmen01/oculus-linux-kernel
cd oculus-linux-kernel
git checkout oculus-quest-pro-kernel-master

Build a raw ARM64 Image using the headset config. Required options include:

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

For another Quest model or kernel release, see HOW_TO_PORT.md.

Initramfs

From this repository:

make initramfs

This downloads and verifies BusyBox 1.36.1, cross-builds it statically for ARM64 and writes:

out/initramfs.gz