How To Make A Custom Kernel

This sourced from: http://www.webos-internals.org/wiki/Custom_Kernels

Contents 1 Toolchain 2 Environment 3 mkimage 4 Build the kernel 5 See More

Toolchain

Download the 2009q1 ARM toolchain

tar xjvf arm-2009q1-203-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
sudo mv arm-2009q1 /usr/local/arm

Environment

Create a file: /usr/local/pre/setup-env:

export PRETOOL_DIR="/usr/local/arm"
(echo "$PATH" | grep -q "${PRETOOL_DIR}") || export PATH="${PRETOOL_DIR}/bin:${PATH}"
export STRIP="arm-none-linux-gnueabi-strip"
export LD="arm-none-linux-gnueabi-ld"
export CC="arm-none-linux-gnueabi-gcc -march=armv4t -mtune=arm920t"
export CPPFLAGS="-isystem${PRETOOL_DIR}/arm/arm-none-linux-gnueabi/include"
export RANLIB="arm-none-linux-gnueabi-ranlib"
export CXX="arm-none-linux-gnueabi-g++ -march=armv4t -mtune=arm920t"
export OBJCOPY="arm-none-linux-gnueabi-objcopy"
export PKG_CONFIG_PATH="${PRETOOL_DIR}/usr/local/lib/pkgconfig"
export PKG_CONFIG_SYSROOT_DIR="${PRETOOL_DIR}/arm/arm-none-linux-gnueabi"
#export LDFLAGS="-L${PRETOOL_DIR}/usr/local/lib -Wl,-rpath-link,${PRETOOL_DIR}/arm/arm-none-linux-gnueabi/lib -Wl,-O1"
export CCLD="arm-none-linux-gnueabi-gcc -march=armv4t -mtune=arm920t"
export MAKE="make"
export CFLAGS="-isystem${PRETOOL_DIR}/usr/local/include -fexpensive-optimizations -fomit-frame-pointer -frename-registers -Os"
export CXXFLAGS="-isystem${PRETOOL_DIR}/arm/arm-none-linux-gnueabi/include -fexpensive-optimizations -fomit-frame-pointer -frename-registers -Os -fpermissive -fvisibility-inlines-hidden"
export F77="arm-none-linux-gnueabi-g77 -march=armv4t -mtune=arm920t"
export AS="arm-none-linux-gnueabi-as"
export AR="arm-none-linux-gnueabi-ar"
export CPP="arm-none-linux-gnueabi-gcc -E"
export OBJDUMP="arm-none-linux-gnueabi-objdump"
export CONFIG_SITE="${PRETOOL_DIR}/arm/site-config"

Run

. /usr/local/pre/setup-env

to set up your environment.

mkimage

mkimage is part of u-boot and is required to build a kernel image. On ubuntu you can install the uboot-mkimage package. Other dists may have similar packages. To build it from source:

1. Create compiler symlinks

cd /usr/local/arm/bin
ln -s arm-none-linux-gnueabi-gcc arm-linux-gcc
ln -s arm-none-linux-gnueabi-ar arm-linux-ar
ln -s arm-none-linux-gnueabi-ld arm-linux-ld
ln -s arm-none-linux-gnueabi-objcopy arm-linux-objcopy
ln -s arm-none-linux-gnueabi-objdump arm-linux-objdump
ln -s arm-none-linux-gnueabi-nm arm-linux-nm

1. Download the u-boot tarball.
2. Extract the tarball and cd into u-boot-2009.06
3. Compile

   make omap3_beagle_config && make 

4. mkimage is in the tools subdirectory. Copy it into /usr/local/bin

Build the kernel

1. Download the prepatched kernel sources. (These are now superseded by the sources available at [http://goo.gl/NZQ7z this link, thanks to jonpry>
2. Download the config and put it in the linux-2.6.35 directory and name it .config (this is superseded - run "make tenderloin_defconfig" to generate the config file)
3. Run make

make && make uImage

1. Optional Flags for Optimization: -march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=softfp

See More

http://www.webos-internals.org/wiki/Research_Pre_Boot_Process