在ubuntu上编译rasbian kernel(for raspberry pi 1)

raspberry pi官网的编译手册写的简洁有力，照着操作即可

https://www.raspberrypi.org/documentation/linux/kernel/building.md

CROSS-COMPILING

First you are going to require a suitable Linux cross-compilation host. We tend to use Ubuntu; since Raspbian is also a Debian distribution it means using similar command lines and so on.

You can either do this using VirtualBox (or VMWare) on Windows, or install it directly onto your computer. For reference you can follow instructions online at Wikihow.
INSTALL TOOLCHAIN

Use the following command:

git clone https://github.com/raspberrypi/tools

You can then copy the toolchain to a common location such as/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian, and add/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin to your $PATH in the .bashrc in your home directory. For 64-bit host systems, use /tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin. While this step is not strictly necessary, it does make it easier for later command lines!
GET SOURCES

To get the sources, refer to the original GitHub repository for the various branches.

$ git clone --depth=1 https://github.com/raspberrypi/linux

BUILD SOURCES

To build the sources for cross-compilation there may be extra dependencies beyond those you've installed by default with Ubuntu. If you find you need other things please submit a pull request to change the documentation.

Enter the following commands to build the sources and Device Tree files.

For Pi 1 or Compute Module:

cd linux
KERNEL=kernel
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcmrpi_defconfig

For Pi 2/3:

cd linux
KERNEL=kernel7
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcm2709_defconfig

Then for both:

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- zImage modules dtbs

Note: To speed up compilation on multiprocessor systems, and get some improvement on single processor ones, use -j n where n is number of processors * 1.5. Alternatively, feel free to experiment and see what works!

中间碰到了一点小麻烦：

arm-linux-gnueabihf-gcc: error while loading shared libraries: 
     libstdc++.so.6: cannot open shared object file: No such file or directory

解决方案也不难：

sudo apt-get install libc6-i386 lib32z1 lib32stdc++6