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Commit af271f68 authored by Mark Yoder's avatar Mark Yoder
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Updated Cross Compiling

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    books/beaglebone-cookbook/07kernel/kernel.rst
    + 50
    − 102
    View file @ af271f68
    ......@@ -265,14 +265,18 @@ To download and compile the kernel, follow these steps:
    .. note::
    If you are using a 64 bit Bone, **git checkout ti-linux-arm64-5.10.y**
    1. The first command clones a repository with the tools to build the kernel for the Bone.
    2. When you know which kernel to try, use *git checkout* to check it out.
    This command checks out branch *ti-linux-5.10.y*.
    3. *build_deb.sh* is the master builder. If needed, it will download the cross compilers
    needed to compile the kernel (`gcc <https://gcc.gnu.org/>`_ is the current cross compiler).
    If there is a kernel at ``~/linux-dev``, it will use it; otherwise,
    it will download a copy to ``ti-linux-kernel-dev/ignore/linux-src``.
    It will then patch the kernel so that it will run on the Bone.
    .. annotations::
    <1> The first command clones a repository with the tools to build the kernel for the Bone.
    <2> When you know which kernel to try, use *git checkout* to check it out.
    This command checks out branch *ti-linux-5.10.y*.
    <3> *build_deb.sh* is the master builder. If needed, it will download the cross compilers
    needed to compile the kernel (`gcc <https://gcc.gnu.org/>`_ is the current cross compiler).
    If there is a kernel at ``~/linux-dev``, it will use it; otherwise,
    it will download a copy to ``ti-linux-kernel-dev/ignore/linux-src``.
    It will then patch the kernel so that it will run on the Bone.
    .. note::
    *build_deb.sh* may ask you to install additional files. Just run **sudo apt install *files*** to
    ......@@ -392,116 +396,58 @@ Reboot and test out the new kernel.
    .. _kernel_using_cross_compiler:
    Using the Installed Cross Compiler
    ===================================
    .. todo
    This should be removed
    Installin a Cross Compiler
    ==========================
    Problem
    --------
    You have followed the instructions in :ref:`kernel_compiling`
    and want to use the cross compiler it has downloaded.
    .. tip::
    You can cross-compile without installing the
    entire kernel source by running the following:
    .. code-block:: bash
    host$ sudo apt install gcc-arm-linux-gnueabihf
    Then skip down to :ref:`kernel_skip_to_here`.
    You want to compile on your host computer and run on the Beagle.
    Solution
    ---------
    :ref:`kernel_compiling` installs a cross compiler, but you need to set up a
    couple of things so that it can be found. :ref:`kernel_compiling` installed the
    kernel and other tools in a directory called ``ti-linux-kernel-dev``. Run the
    following commands to find the path to the cross compiler:
    .. code-block:: bash
    host$ cd ti-linux-kernel-dev/dl
    host$ ls
    gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux
    gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.xz
    Here, the path to the cross compiler contains the version number
    of the compiler. Yours might be different from mine. *cd* into it:
    .. code-block:: bash
    host$ cd gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux
    host$ ls
    20130415-gcc-linaro-arm-linux-gnueabihf bin libexec
    arm-linux-gnueabihf lib share
    At this point, we are interested in what's in ``bin``:
    .. code-block:: bash
    host$ cd bin
    host$ ls
    arm-linux-gnueabihf-addr2line arm-linux-gnueabihf-gfortran
    arm-linux-gnueabihf-ar arm-linux-gnueabihf-gprof
    arm-linux-gnueabihf-as arm-linux-gnueabihf-ld
    arm-linux-gnueabihf-c+* arm-linux-gnueabihf-ld.bfd
    arm-linux-gnueabihf-c++filt arm-linux-gnueabihf-ldd
    arm-linux-gnueabihf-cpp arm-linux-gnueabihf-ld.gold
    arm-linux-gnueabihf-ct-ng.config arm-linux-gnueabihf-nm
    arm-linux-gnueabihf-elfedit arm-linux-gnueabihf-objcopy
    arm-linux-gnueabihf-g+* arm-linux-gnueabihf-objdump
    arm-linux-gnueabihf-gcc arm-linux-gnueabihf-pkg-config
    arm-linux-gnueabihf-gcc-4.7.3 arm-linux-gnueabihf-pkg-config-real
    arm-linux-gnueabihf-gcc-ar arm-linux-gnueabihf-ranlib
    arm-linux-gnueabihf-gcc-nm arm-linux-gnueabihf-readelf
    arm-linux-gnueabihf-gcc-ranlib arm-linux-gnueabihf-size
    arm-linux-gnueabihf-gcov arm-linux-gnueabihf-strings
    arm-linux-gnueabihf-gdb arm-linux-gnueabihf-strip
    What you see are all the cross-development tools. You need to add this directory
    to the *$PATH* the shell uses to find the commands it runs:
    Run the following:
    .. code-block:: bash
    .. tabs::
    host$ pwd
    /home/yoder/BeagleBoard/ti-linux-kernel-dev/dl/\
    gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin
    host$ echo $PATH
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:\
    /usr/games:/usr/local/games
    .. group-tab:: 32-bit
    .. code-block:: bash
    The first command displays the path to the directory where the cross-development
    tools are located. The second shows which directories are searched to find commands
    to be run. Currently, the cross-development tools are not in the *$PATH*. Let's add it:
    host$ sudo apt install gcc-arm-linux-gnueabihf
    .. code-block:: bash
    .. group-tab:: 64-bit
    host$ export PATH=`pwd`:$PATH
    host$ echo $PATH
    /home/yoder/BeagleBoard/ti-linux-kernel-dev/dl/\
    gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin:\
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:\
    /usr/games:/usr/local/games
    .. code-block:: bash
    host$ sudo apt install gcc-aarch64-linux-gnu
    .. note::
    Those are backtick characters (left of the "1" key on your keyboard) around *pwd*.
    From now on use **arm** if you are using a 32-bit machine and
    **aarch64** if you are using a 64-bit machine.
    This installs a cross compiler, but you need to set up a
    couple of things so that it can be found. At the command prompt,
    enter **arm-<TAB><TAB>** to see what was installed.
    The second line shows the *$PATH* now contains the directory with the cross-development tools.
    .. code-block:: bash
    .. _kernel_skip_to_here:
    host$ arm-<TAB><TAB>
    arm-linux-gnueabihf-addr2line arm-linux-gnueabihf-gcc-nm arm-linux-gnueabihf-ld.bfd
    arm-linux-gnueabihf-ar arm-linux-gnueabihf-gcc-nm-11 arm-linux-gnueabihf-ld.gold
    arm-linux-gnueabihf-as arm-linux-gnueabihf-gcc-ranlib arm-linux-gnueabihf-lto-dump-11
    arm-linux-gnueabihf-c++filt arm-linux-gnueabihf-gcc-ranlib-11 arm-linux-gnueabihf-nm
    arm-linux-gnueabihf-cpp arm-linux-gnueabihf-gcov arm-linux-gnueabihf-objcopy
    arm-linux-gnueabihf-cpp-11 arm-linux-gnueabihf-gcov-11 arm-linux-gnueabihf-objdump
    arm-linux-gnueabihf-dwp arm-linux-gnueabihf-gcov-dump arm-linux-gnueabihf-ranlib
    arm-linux-gnueabihf-elfedit arm-linux-gnueabihf-gcov-dump-11 arm-linux-gnueabihf-readelf
    arm-linux-gnueabihf-gcc arm-linux-gnueabihf-gcov-tool arm-linux-gnueabihf-size
    arm-linux-gnueabihf-gcc-11 arm-linux-gnueabihf-gcov-tool-11 arm-linux-gnueabihf-strings
    arm-linux-gnueabihf-gcc-ar arm-linux-gnueabihf-gprof arm-linux-gnueabihf-strip
    arm-linux-gnueabihf-gcc-ar-11 arm-linux-gnueabihf-ld
    What you see are all the cross-development tools.
    Setting Up Variables
    =====================
    ......@@ -513,15 +459,15 @@ Now, set up a couple of variables to know which compiler you are using:
    host$ export ARCH=arm
    host$ export CROSS_COMPILE=arm-linux-gnueabihf-
    These lines set up the standard environmental variables so that you can determine which cross-development
    tools to use. Test the cross compiler by adding :ref:`kernel_helloWorld` to a file named _helloWorld.c_.
    .. _kernel_helloWorld:
    .. literalinclude:: ../code/07kernel/helloWorld.c
    :caption: Simple helloWorld.c to test cross compiling (helloWorld.c)
    :linenos:
    :language: c
    :caption: Simple helloWorld.c to test cross compiling (helloWorld.c)
    :linenos:
    :download:`helloWorld.c <../code/07kernel/helloWorld.c>`
    ......@@ -535,9 +481,11 @@ You can then cross-compile by using the following commands:
    dynamically linked (uses shared libs), for GNU/Linux 2.6.31,
    BuildID[sha1]=0x10182364352b9f3cb15d1aa61395aeede11a52ad, not stripped
    The *file* command shows that *a.out* was compiled for an ARM processor.
    .. todo
    Need to install libc.
    .. _kernel_patches:
    Applying Patches
    ......
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