1. Get toolchains from CodeSourcery (Choose ARM GNU/Linux and IA32 GNU/Linux).
2. Get kernl source code from here.
3. Deploy toolcains and kernel source and enter in the kernel source tree.
$ mkdir -p android
$ cd android
$ tar xjvf ../arm-2007q3-51-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
$ tar xzvf ../linux-2.6.23-android-m3-rc20.tar.gz
$ cd kernel
4. Get the config.gz from the running emulator by the following way.
$ adb pull /proc/config.gz .
5. Decommpress the config.gz and rename it as .config
$ gunzip config.gz
$ mv config .config
6. Specify CROSS_COMPILE in the Makefile.
CROSS_COMPILE=../arm-2007q3/bin/arm-none-linux-gnueabi-
7. Comment out LDFLAGS_BUILD_ID[*1] in the same Makefile.
#LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
$(call ld-option, -Wl$(comma)--build-id,))
8. Make the kernel
$ make
9. Check zImage is created and the size is nearly same as the kernel-qemu in the Andorid SDK.
$ ls -l arch/arm/boot/zImage
-rwxrwxr-x 1 motz motz 1234712 2007-12-01 18:06 arch/arm/boot/zImage
$ ls -l $SDK/tools/lib/images/kernel-qemu
-rwxrwxr-x 1 motz motz 1245836 2007-11-12 5:59 ...sdk/tools/lib/images/kernel-qemu
10. Run emulator with the created kernel.
$ emulator -kernel arch/arm/boot/zImage
[*1]: The LDFLAGS_BUILD_ID enables --build-id option of ld if available. The --build-id option is relatively new. The current emulator does not seem to support the kernel linked with this option. See here if you are interested in the detail of this option.
