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Diffstat (limited to 'poky/documentation/kernel-dev/common.rst')
| -rw-r--r-- | poky/documentation/kernel-dev/common.rst | 300 |
1 files changed, 117 insertions, 183 deletions
diff --git a/poky/documentation/kernel-dev/common.rst b/poky/documentation/kernel-dev/common.rst index 56217b9d3..de62df5b1 100644 --- a/poky/documentation/kernel-dev/common.rst +++ b/poky/documentation/kernel-dev/common.rst @@ -54,8 +54,7 @@ section: 1. *Initialize the BitBake Environment:* Before building an extensible SDK, you need to initialize the BitBake build environment by sourcing - the build environment script (i.e. :ref:`structure-core-script`): - :: + the build environment script (i.e. :ref:`structure-core-script`):: $ cd poky $ source oe-init-build-env @@ -71,7 +70,7 @@ section: :term:`MACHINE` variable is set to "qemux86-64", which is fine if you are building for the QEMU emulator in 64-bit mode. However, if you are not, you need to set the - ``MACHINE`` variable appropriately in your ``conf/local.conf`` file + :term:`MACHINE` variable appropriately in your ``conf/local.conf`` file found in the :term:`Build Directory` (i.e. ``poky/build`` in this example). @@ -83,16 +82,14 @@ section: In this example we wish to build for qemux86 so we must set the ``MACHINE`` variable to "qemux86" and also add the "kernel-modules". - As described we do this by appending to ``conf/local.conf``: - :: + As described we do this by appending to ``conf/local.conf``:: MACHINE = "qemux86" MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules" 3. *Create a Layer for Patches:* You need to create a layer to hold patches created for the kernel image. You can use the - ``bitbake-layers create-layer`` command as follows: - :: + ``bitbake-layers create-layer`` command as follows:: $ cd poky/build $ bitbake-layers create-layer ../../meta-mylayer @@ -116,8 +113,7 @@ section: 4. *Inform the BitBake Build Environment About Your Layer:* As directed when you created your layer, you need to add the layer to the :term:`BBLAYERS` variable in the - ``bblayers.conf`` file as follows: - :: + ``bblayers.conf`` file as follows:: $ cd poky/build $ bitbake-layers add-layer ../../meta-mylayer @@ -125,16 +121,14 @@ section: $ 5. *Build the Extensible SDK:* Use BitBake to build the extensible SDK - specifically for use with images to be run using QEMU: - :: + specifically for use with images to be run using QEMU:: $ cd poky/build $ bitbake core-image-minimal -c populate_sdk_ext Once the build finishes, you can find the SDK installer file (i.e. - ``*.sh`` file) in the following directory: - :: + ``*.sh`` file) in the following directory:: poky/build/tmp/deploy/sdk @@ -143,8 +137,7 @@ section: 6. *Install the Extensible SDK:* Use the following command to install the SDK. For this example, install the SDK in the default - ``poky_sdk`` directory: - :: + ``poky_sdk`` directory:: $ cd poky/build/tmp/deploy/sdk $ ./poky-glibc-x86_64-core-image-minimal-i586-toolchain-ext-&DISTRO;.sh @@ -172,8 +165,7 @@ section: BitBake shell used to build the installer. After opening a new shell, run the SDK environment setup script as - directed by the output from installing the SDK: - :: + directed by the output from installing the SDK:: $ source poky_sdk/environment-setup-i586-poky-linux "SDK environment now set up; additionally you may now run devtool to perform development tasks. @@ -186,8 +178,7 @@ section: 8. *Build the Clean Image:* The final step in preparing to work on the kernel is to build an initial image using ``devtool`` in the new - terminal you just set up and initialized for SDK work: - :: + terminal you just set up and initialized for SDK work:: $ devtool build-image Parsing recipes: 100% |##########################################| Time: 0:00:05 @@ -257,7 +248,7 @@ section: :term:`MACHINE` variable is set to "qemux86-64", which is fine if you are building for the QEMU emulator in 64-bit mode. However, if you are not, you need to set the - ``MACHINE`` variable appropriately in your ``conf/local.conf`` file + :term:`MACHINE` variable appropriately in your ``conf/local.conf`` file found in the :term:`Build Directory` (i.e. ``poky/build`` in this example). @@ -269,16 +260,14 @@ section: In this example we wish to build for qemux86 so we must set the ``MACHINE`` variable to "qemux86" and also add the "kernel-modules". - As described we do this by appending to ``conf/local.conf``: - :: + As described we do this by appending to ``conf/local.conf``:: MACHINE = "qemux86" MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules" 3. *Create a Layer for Patches:* You need to create a layer to hold patches created for the kernel image. You can use the - ``bitbake-layers create-layer`` command as follows: - :: + ``bitbake-layers create-layer`` command as follows:: $ cd poky/build $ bitbake-layers create-layer ../../meta-mylayer @@ -301,8 +290,7 @@ section: 4. *Inform the BitBake Build Environment About Your Layer:* As directed when you created your layer, you need to add the layer to the :term:`BBLAYERS` variable in the - ``bblayers.conf`` file as follows: - :: + ``bblayers.conf`` file as follows:: $ cd poky/build $ bitbake-layers add-layer ../../meta-mylayer @@ -350,8 +338,7 @@ section: the ``yocto-4.12`` branch. The following commands show how to create a local copy of the - ``yocto-kernel-cache`` and be in the ``yocto-4.12`` branch: - :: + ``yocto-kernel-cache`` and switch to the ``yocto-4.12`` branch:: $ cd ~ $ git clone git://git.yoctoproject.org/yocto-kernel-cache --branch yocto-4.12 @@ -394,8 +381,7 @@ following section describes how to create a layer without the aid of tools. These steps assume creation of a layer named ``mylayer`` in your home directory: -1. *Create Structure*: Create the layer's structure: - :: +1. *Create Structure*: Create the layer's structure:: $ mkdir meta-mylayer $ mkdir meta-mylayer/conf @@ -409,8 +395,7 @@ home directory: 2. *Create the Layer Configuration File*: Move to the ``meta-mylayer/conf`` directory and create the ``layer.conf`` file as - follows: - :: + follows:: # We have a conf and classes directory, add to BBPATH BBPATH .= ":${LAYERDIR}" @@ -429,8 +414,7 @@ home directory: ``meta-mylayer/recipes-kernel/linux`` directory and create the kernel's append file. This example uses the ``linux-yocto-4.12`` kernel. Thus, the name of the append file is - ``linux-yocto_4.12.bbappend``: - :: + ``linux-yocto_4.12.bbappend``:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" @@ -483,17 +467,15 @@ The append file should initially extend the :term:`FILESPATH` search path by prepending the directory that contains your files to the :term:`FILESEXTRAPATHS` -variable as follows: -:: +variable as follows:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" The path ``${``\ :term:`THISDIR`\ ``}/${``\ :term:`PN`\ ``}`` expands to "linux-yocto" in the current directory for this example. If you add any new files that modify the kernel recipe and you have -extended ``FILESPATH`` as described above, you must place the files in -your layer in the following area: -:: +extended :term:`FILESPATH` as described above, you must place the files in +your layer in the following area:: your-layer/recipes-kernel/linux/linux-yocto/ @@ -509,7 +491,7 @@ As an example, consider the following append file used by the BSPs in meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend -The following listing shows the file. Be aware that the actual commit ID +Here are the contents of this file. Be aware that the actual commit ID strings in this example listing might be different than the actual strings in the file from the ``meta-yocto-bsp`` layer upstream. :: @@ -571,7 +553,7 @@ the append file. For example, suppose you had some configuration options in a file called ``network_configs.cfg``. You can place that file inside a directory -named ``linux-yocto`` and then add a ``SRC_URI`` statement such as the +named ``linux-yocto`` and then add a :term:`SRC_URI` statement such as the following to the append file. When the OpenEmbedded build system builds the kernel, the configuration options are picked up and applied. :: @@ -581,9 +563,8 @@ the kernel, the configuration options are picked up and applied. To group related configurations into multiple files, you perform a similar procedure. Here is an example that groups separate configurations specifically for Ethernet and graphics into their own -files and adds the configurations by using a ``SRC_URI`` statement like -the following in your append file: -:: +files and adds the configurations by using a :term:`SRC_URI` statement like +the following in your append file:: SRC_URI += "file://myconfig.cfg \ file://eth.cfg \ @@ -597,7 +578,7 @@ recipe is processed. .. note:: - Other methods exist to accomplish grouping and defining configuration + There are other ways of grouping and defining configuration options. For example, if you are working with a local clone of the kernel repository, you could checkout the kernel's ``meta`` branch, make your changes, and then push the changes to the local bare clone @@ -608,8 +589,8 @@ recipe is processed. In general, however, the Yocto Project maintainers take care of moving the ``SRC_URI``-specified configuration options to the - kernel's ``meta`` branch. Not only is it easier for BSP developers to - not have to worry about putting those configurations in the branch, + kernel's ``meta`` branch. Not only is it easier for BSP developers + not to have to put those configurations in the branch, but having the maintainers do it allows them to apply 'global' knowledge about the kinds of common configuration options multiple BSPs in the tree are typically using. This allows for promotion of @@ -627,8 +608,7 @@ reference them in :term:`SRC_URI` statements. For example, you can apply a three-patch series by adding the following -lines to your linux-yocto ``.bbappend`` file in your layer: -:: +lines to your linux-yocto ``.bbappend`` file in your layer:: SRC_URI += "file://0001-first-change.patch" SRC_URI += "file://0002-second-change.patch" @@ -658,19 +638,27 @@ If you have a complete, working Linux kernel ``.config`` file you want to use for the configuration, as before, copy that file to the appropriate ``${PN}`` directory in your layer's ``recipes-kernel/linux`` directory, and rename the copied file to "defconfig". Then, add the -following lines to the linux-yocto ``.bbappend`` file in your layer: -:: +following lines to the linux-yocto ``.bbappend`` file in your layer:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" SRC_URI += "file://defconfig" -The ``SRC_URI`` tells the build system how to search +The :term:`SRC_URI` tells the build system how to search for the file, while the :term:`FILESEXTRAPATHS` extends the :term:`FILESPATH` variable (search directories) to include the ``${PN}`` directory you created to hold the configuration changes. +You can also use a regular ``defconfig`` file, as generated by the +:ref:`ref-tasks-savedefconfig` +task instead of a complete ``.config`` file. This only specifies the +non-default configuration values. You need to additionally set +:term:`KCONFIG_MODE` +in the linux-yocto ``.bbappend`` file in your layer:: + + KCONFIG_MODE = "alldefconfig" + .. note:: The build system applies the configurations from the ``defconfig`` @@ -685,8 +673,7 @@ Generally speaking, the preferred approach is to determine the incremental change you want to make and add that as a configuration fragment. For example, if you want to add support for a basic serial console, create a file named ``8250.cfg`` in the ``${PN}`` directory -with the following content (without indentation): -:: +with the following content (without indentation):: CONFIG_SERIAL_8250=y CONFIG_SERIAL_8250_CONSOLE=y @@ -697,9 +684,8 @@ with the following content (without indentation): CONFIG_SERIAL_CORE_CONSOLE=y Next, include this -configuration fragment and extend the ``FILESPATH`` variable in your -``.bbappend`` file: -:: +configuration fragment and extend the :term:`FILESPATH` variable in your +``.bbappend`` file:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" SRC_URI += "file://8250.cfg" @@ -718,8 +704,7 @@ It might be desirable to have kernel configuration fragment support through a ``defconfig`` file that is pulled from the kernel source tree for the configured machine. By default, the OpenEmbedded build system looks for ``defconfig`` files in the layer used for Metadata, which is -"out-of-tree", and then configures them using the following: -:: +"out-of-tree", and then configures them using the following:: SRC_URI += "file://defconfig" @@ -732,16 +717,14 @@ append files, you can direct the OpenEmbedded build system to use a ``defconfig`` file that is "in-tree". To specify an "in-tree" ``defconfig`` file, use the following statement -form: -:: +form:: KBUILD_DEFCONFIG_KMACHINE ?= "defconfig_file" Here is an example -that assigns the ``KBUILD_DEFCONFIG`` variable based on "raspberrypi2" +that assigns the :term:`KBUILD_DEFCONFIG` variable based on "raspberrypi2" and provides the path to the "in-tree" ``defconfig`` file to be used for -a Raspberry Pi 2, which is based on the Broadcom 2708/2709 chipset: -:: +a Raspberry Pi 2, which is based on the Broadcom 2708/2709 chipset:: KBUILD_DEFCONFIG_raspberrypi2 ?= "bcm2709_defconfig" @@ -751,7 +734,7 @@ Aside from modifying your kernel recipe and providing your own a kernel's ``linux-``\ `machine`\ ``.inc`` file). In other words, if the build system detects a statement that identifies an "out-of-tree" ``defconfig`` file, that statement will override your -``KBUILD_DEFCONFIG`` variable. +:term:`KBUILD_DEFCONFIG` variable. See the :term:`KBUILD_DEFCONFIG` @@ -792,15 +775,14 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" section for more information. - Use the following ``devtool`` command to check out the code: - :: + Use the following ``devtool`` command to check out the code:: $ devtool modify linux-yocto .. note:: - During the checkout operation, a bug exists that could cause - errors such as the following to appear: + During the checkout operation, there is a bug that could cause + errors such as the following: .. code-block:: none @@ -819,14 +801,12 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se noted where you can find the source files (e.g. ``poky_sdk/workspace/sources/linux-yocto``). Change to where the kernel source code is before making your edits to the - ``calibrate.c`` file: - :: + ``calibrate.c`` file:: $ cd poky_sdk/workspace/sources/linux-yocto 2. *Edit the source file*: Edit the ``init/calibrate.c`` file to have - the following changes: - :: + the following changes:: void calibrate_delay(void) { @@ -846,8 +826,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se . 3. *Build the Updated Kernel Source:* To build the updated kernel - source, use ``devtool``: - :: + source, use ``devtool``:: $ devtool build linux-yocto @@ -872,8 +851,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se using QEMU to verify your changes: 1. *Boot the image*: Boot the modified image in the QEMU emulator - using this command: - :: + using this command:: $ runqemu qemux86 @@ -891,8 +869,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se 6. *Stage and commit your changes*: Within your eSDK terminal, change your working directory to where you modified the ``calibrate.c`` file - and use these Git commands to stage and commit your changes: - :: + and use these Git commands to stage and commit your changes:: $ cd poky_sdk/workspace/sources/linux-yocto $ git status @@ -921,8 +898,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se image that includes your kernel patches. Execute the following command from your :term:`Build Directory` in the terminal - set up to run BitBake: - :: + set up to run BitBake:: $ cd poky/build $ bitbake core-image-minimal @@ -966,14 +942,12 @@ Section. 1. *Change the working directory*: You need to locate the source files in the local copy of the kernel Git repository. Change to where the kernel source code is before making your edits to the - ``calibrate.c`` file: - :: + ``calibrate.c`` file:: $ cd ~/linux-yocto-4.12/init 2. *Edit the source file*: Edit the ``calibrate.c`` file to have the - following changes: - :: + following changes:: void calibrate_delay(void) { @@ -993,8 +967,7 @@ Section. . 2. *Stage and Commit Your Changes:* Use standard Git commands to stage - and commit the changes you just made: - :: + and commit the changes you just made:: $ git add calibrate.c $ git commit -m "calibrate.c - Added some printk statements" @@ -1009,13 +982,11 @@ Section. updated kernel source files. Add :term:`SRC_URI` and :term:`SRCREV` statements similar - to the following to your ``local.conf``: - :: + to the following to your ``local.conf``:: $ cd poky/build/conf - Add the following to the ``local.conf``: - :: + Add the following to the ``local.conf``:: SRC_URI_pn-linux-yocto = "git:///path-to/linux-yocto-4.12;protocol=file;name=machine;branch=standard/base; \ git:///path-to/yocto-kernel-cache;protocol=file;type=kmeta;name=meta;branch=yocto-4.12;destsuffix=${KMETA}" @@ -1031,16 +1002,14 @@ Section. 4. *Build the Image:* With the source modified, your changes staged and committed, and the ``local.conf`` file pointing to the kernel files, - you can now use BitBake to build the image: - :: + you can now use BitBake to build the image:: $ cd poky/build $ bitbake core-image-minimal 5. *Boot the image*: Boot the modified image in the QEMU emulator using this command. When prompted to login to the QEMU console, use "root" - with no password: - :: + with no password:: $ cd poky/build $ runqemu qemux86 @@ -1059,8 +1028,7 @@ Section. 7. *Generate the Patch File:* Once you are sure that your patch works correctly, you can generate a ``*.patch`` file in the kernel source - repository: - :: + repository:: $ cd ~/linux-yocto-4.12/init $ git format-patch -1 @@ -1073,8 +1041,7 @@ Section. ``meta-mylayer``. When the layer was created using the ``yocto-create`` script, no additional hierarchy was created to support patches. Before moving the patch file, you need to add - additional structure to your layer using the following commands: - :: + additional structure to your layer using the following commands:: $ cd ~/meta-mylayer $ mkdir recipes-kernel @@ -1083,8 +1050,7 @@ Section. Once you have created this hierarchy in your layer, you can move the patch file using the - following command: - :: + following command:: $ mv ~/linux-yocto-4.12/init/0001-calibrate.c-Added-some-printk-statements.patch ~/meta-mylayer/recipes-kernel/linux/linux-yocto @@ -1093,8 +1059,7 @@ Section. the OpenEmbedded build system to find the patch. The append file needs to be in your layer's ``recipes-kernel/linux`` directory and it must be named ``linux-yocto_4.12.bbappend`` and have the following - contents: - :: + contents:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" SRC_URI_append = "file://0001-calibrate.c-Added-some-printk-statements.patch" @@ -1113,8 +1078,7 @@ Section. To build ``core-image-minimal`` again and see the effects of your patch, you can essentially eliminate the temporary source files saved in ``poky/build/tmp/work/...`` and residual effects of the build by entering - the following sequence of commands: - :: + the following sequence of commands:: $ cd poky/build $ bitbake -c cleanall yocto-linux @@ -1160,8 +1124,7 @@ environment, you must do the following: - You must be sure of the state of your build's configuration in the :term:`Source Directory`. -- Your build host must have the following two packages installed: - :: +- Your build host must have the following two packages installed:: libncurses5-dev libtinfo-dev @@ -1169,8 +1132,7 @@ environment, you must do the following: The following commands initialize the BitBake environment, run the :ref:`ref-tasks-kernel_configme` task, and launch ``menuconfig``. These commands assume the Source -Directory's top-level folder is ``poky``: -:: +Directory's top-level folder is ``poky``:: $ cd poky $ source oe-init-build-env @@ -1232,8 +1194,7 @@ the ``.config`` file would be: Within the ``.config`` file, you can see the kernel settings. For example, the following entry shows that symmetric multi-processor -support is not set: -:: +support is not set:: # CONFIG_SMP is not set @@ -1274,8 +1235,7 @@ your layer's ``recipes-kernel/linux`` directory, and rename the copied file to "defconfig" (e.g. ``~/meta-mylayer/recipes-kernel/linux/linux-yocto/defconfig``). Then, add the following lines to the linux-yocto ``.bbappend`` file in your -layer: -:: +layer:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" SRC_URI += "file://defconfig" @@ -1323,8 +1283,7 @@ appear in the ``.config`` file, which is in the :term:`Build Directory`. It is simple to create a configuration fragment. One method is to use shell commands. For example, issuing the following from the shell creates a configuration fragment file named ``my_smp.cfg`` that enables -multi-processor support within the kernel: -:: +multi-processor support within the kernel:: $ echo "CONFIG_SMP=y" >> my_smp.cfg @@ -1342,18 +1301,16 @@ To create a configuration fragment using this method, follow these steps: 1. *Complete a Build Through Kernel Configuration:* Complete a build at - least through the kernel configuration task as follows: - :: + least through the kernel configuration task as follows:: $ bitbake linux-yocto -c kernel_configme -f This step ensures that you create a - ``.config`` file from a known state. Because situations exist where + ``.config`` file from a known state. Because there are situations where your build state might become unknown, it is best to run this task prior to starting ``menuconfig``. -2. *Launch menuconfig:* Run the ``menuconfig`` command: - :: +2. *Launch menuconfig:* Run the ``menuconfig`` command:: $ bitbake linux-yocto -c menuconfig @@ -1361,8 +1318,7 @@ steps: to prepare a configuration fragment. The resulting file ``fragment.cfg`` is placed in the ``${``\ :term:`WORKDIR`\ ``}`` - directory: - :: + directory:: $ bitbake linux-yocto -c diffconfig @@ -1387,18 +1343,16 @@ options in a file called ``myconfig.cfg``. If you put that file inside a directory named ``linux-yocto`` that resides in the same directory as the kernel's append file within your layer and then add the following statements to the kernel's append file, those configuration options will -be picked up and applied when the kernel is built: -:: +be picked up and applied when the kernel is built:: FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:" SRC_URI += "file://myconfig.cfg" As mentioned earlier, you can group related configurations into multiple -files and name them all in the ``SRC_URI`` statement as well. For +files and name them all in the :term:`SRC_URI` statement as well. For example, you could group separate configurations specifically for Ethernet and graphics into their own files and add those by using a -``SRC_URI`` statement like the following in your append file: -:: +:term:`SRC_URI` statement like the following in your append file:: SRC_URI += "file://myconfig.cfg \ file://eth.cfg \ @@ -1409,8 +1363,7 @@ Validating Configuration You can use the :ref:`ref-tasks-kernel_configcheck` -task to provide configuration validation: -:: +task to provide configuration validation:: $ bitbake linux-yocto -c kernel_configcheck -f @@ -1537,8 +1490,7 @@ To streamline the configuration, do the following: successfully. Use this configuration file as your baseline. 2. *Run Configure and Check Tasks:* Separately run the - ``do_kernel_configme`` and ``do_kernel_configcheck`` tasks: - :: + ``do_kernel_configme`` and ``do_kernel_configcheck`` tasks:: $ bitbake linux-yocto -c kernel_configme -f $ bitbake linux-yocto -c kernel_configcheck -f @@ -1572,8 +1524,7 @@ Expanding Variables Sometimes it is helpful to determine what a variable expands to during a build. You can examine the values of variables by examining the output of the ``bitbake -e`` command. The output is long and is more -easily managed in a text file, which allows for easy searches: -:: +easily managed in a text file, which allows for easy searches:: $ bitbake -e virtual/kernel > some_text_file @@ -1585,20 +1536,18 @@ Working with a "Dirty" Kernel Version String ============================================ If you build a kernel image and the version string has a "+" or a -"-dirty" at the end, uncommitted modifications exist in the kernel's +"-dirty" at the end, it means there are uncommitted modifications in the kernel's source directory. Follow these steps to clean up the version string: 1. *Discover the Uncommitted Changes:* Go to the kernel's locally cloned Git repository (source directory) and use the following Git command - to list the files that have been changed, added, or removed: - :: + to list the files that have been changed, added, or removed:: $ git status 2. *Commit the Changes:* You should commit those changes to the kernel source tree regardless of whether or not you will save, export, or - use the changes: - :: + use the changes:: $ git add $ git commit -s -a -m "getting rid of -dirty" @@ -1633,8 +1582,7 @@ linux-yocto custom recipe (``linux-yocto-custom.bb``) that uses ``kernel.org`` sources and the Yocto Project Linux kernel tools for managing kernel Metadata. You can find this recipe in the ``poky`` Git repository of the Yocto Project :yocto_git:`Source Repository <>` -at: -:: +at:: poky/meta-skeleton/recipes-kernel/linux/linux-yocto-custom.bb @@ -1655,8 +1603,7 @@ Here are some basic steps you can use to work with your own sources: ``defconfig`` file or configuration fragment files in your layer. When you use the ``linux-yocto-custom.bb`` recipe, you must specify a configuration. If you do not have a ``defconfig`` file, you can run - the following: - :: + the following:: $ make defconfig @@ -1668,7 +1615,7 @@ Here are some basic steps you can use to work with your own sources: Running the ``make defconfig`` command results in the default configuration for your architecture as defined by your kernel. - However, no guarantee exists that this configuration is valid for + However, there is no guarantee that this configuration is valid for your use case, or that your board will even boot. This is particularly true for non-x86 architectures. @@ -1681,11 +1628,11 @@ Here are some basic steps you can use to work with your own sources: appropriate for your project: - :term:`SRC_URI`: The - ``SRC_URI`` should specify a Git repository that uses one of the + :term:`SRC_URI` should specify a Git repository that uses one of the supported Git fetcher protocols (i.e. ``file``, ``git``, ``http``, - and so forth). The ``SRC_URI`` variable should also specify either + and so forth). The :term:`SRC_URI` variable should also specify either a ``defconfig`` file or some configuration fragment files. The - skeleton recipe provides an example ``SRC_URI`` as a syntax + skeleton recipe provides an example :term:`SRC_URI` as a syntax reference. - :term:`LINUX_VERSION`: @@ -1703,17 +1650,16 @@ Here are some basic steps you can use to work with your own sources: indicate to the OpenEmbedded build system that the recipe has changed. - - :term:`PV`: The default ``PV`` + - :term:`PV`: The default :term:`PV` assignment is typically adequate. It combines the - ``LINUX_VERSION`` with the Source Control Manager (SCM) revision + :term:`LINUX_VERSION` with the Source Control Manager (SCM) revision as derived from the :term:`SRCPV` variable. The combined results are a string with the following - form: - :: + form:: 3.19.11+git1+68a635bf8dfb64b02263c1ac80c948647cc76d5f_1+218bd8d2022b9852c60d32f0d770931e3cf343e2 - While lengthy, the extra verbosity in ``PV`` helps ensure you are + While lengthy, the extra verbosity in :term:`PV` helps ensure you are using the exact sources from which you intend to build. - :term:`COMPATIBLE_MACHINE`: @@ -1723,8 +1669,7 @@ Here are some basic steps you can use to work with your own sources: triggers an explicit build failure. You must change it to match a list of the machines that your new recipe supports. For example, to support the ``qemux86`` and ``qemux86-64`` machines, use the - following form: - :: + following form:: COMPATIBLE_MACHINE = "qemux86|qemux86-64" @@ -1807,8 +1752,7 @@ Typically, you will need to set the following variables: Depending on the build system used by the module sources, you might need to make some adjustments. For example, a typical module ``Makefile`` -looks much like the one provided with the ``hello-mod`` template: -:: +looks much like the one provided with the ``hello-mod`` template:: obj-m := hello.o @@ -1829,7 +1773,7 @@ information to build modules. If your module ``Makefile`` uses a different variable, you might want to override the :ref:`ref-tasks-compile` step, or create a patch to the ``Makefile`` to work with the more typical -``KERNEL_SRC`` or ``KERNEL_PATH`` variables. +:term:`KERNEL_SRC` or :term:`KERNEL_PATH` variables. After you have prepared your recipe, you will likely want to include the module in your images. To do this, see the documentation for the @@ -1845,8 +1789,7 @@ them appropriately for your machine configuration file: - :term:`MACHINE_EXTRA_RRECOMMENDS` Modules are often not required for boot and can be excluded from certain -build configurations. The following allows for the most flexibility: -:: +build configurations. The following allows for the most flexibility:: MACHINE_EXTRA_RRECOMMENDS += "kernel-module-mymodule" @@ -1895,26 +1838,22 @@ branch. $ git whatchanged origin/standard/base..origin/standard/emenlow -To see short, one line summaries of changes use the ``git log`` command: -:: +To see short, one line summaries of changes use the ``git log`` command:: $ git log --oneline origin/standard/base..origin/standard/emenlow -Use this command to see code differences for the changes: -:: +Use this command to see code differences for the changes:: $ git diff origin/standard/base..origin/standard/emenlow Use this command to see the commit log messages and the text -differences: -:: +differences:: $ git show origin/standard/base..origin/standard/emenlow Use this command to create individual patches for each change. Here is an example that creates patch files for each commit and places them -in your ``Documents`` directory: -:: +in your ``Documents`` directory:: $ git format-patch -o $HOME/Documents origin/standard/base..origin/standard/emenlow @@ -1923,15 +1862,13 @@ Showing a Particular Feature or Branch Change Tags in the Yocto Project kernel tree divide changes for significant features or branches. The ``git show`` tag command shows changes based -on a tag. Here is an example that shows ``systemtap`` changes: -:: +on a tag. Here is an example that shows ``systemtap`` changes:: $ git show systemtap You can use the ``git branch --contains`` tag command to show the branches that contain a particular feature. This command shows -the branches that contain the ``systemtap`` feature: -:: +the branches that contain the ``systemtap`` feature:: $ git branch --contains systemtap @@ -1949,23 +1886,23 @@ build stops. Kernel features are the last elements processed for configuring and patching the kernel. Therefore, adding features in this manner is a way to enforce specific features are present and enabled without needing to do a full audit of any other layer's additions to the -``SRC_URI`` statement. +:term:`SRC_URI` statement. You add a kernel feature by providing the feature as part of the -``KERNEL_FEATURES`` variable and by providing the path to the feature's +:term:`KERNEL_FEATURES` variable and by providing the path to the feature's ``.scc`` file, which is relative to the root of the kernel Metadata. The OpenEmbedded build system searches all forms of kernel Metadata on the -``SRC_URI`` statement regardless of whether the Metadata is in the +:term:`SRC_URI` statement regardless of whether the Metadata is in the "kernel-cache", system kernel Metadata, or a recipe-space Metadata (i.e. part of the kernel recipe). See the ":ref:`kernel-dev/advanced:kernel metadata location`" section for additional information. -When you specify the feature's ``.scc`` file on the ``SRC_URI`` +When you specify the feature's ``.scc`` file on the :term:`SRC_URI` statement, the OpenEmbedded build system adds the directory of that ``.scc`` file along with all its subdirectories to the kernel feature search path. Because subdirectories are searched, you can reference a -single ``.scc`` file in the ``SRC_URI`` statement to reference multiple +single ``.scc`` file in the :term:`SRC_URI` statement to reference multiple kernel features. Consider the following example that adds the "test.scc" feature to the @@ -1973,7 +1910,7 @@ build. 1. *Create the Feature File:* Create a ``.scc`` file and locate it just as you would any other patch file, ``.cfg`` file, or fetcher item you - specify in the ``SRC_URI`` statement. + specify in the :term:`SRC_URI` statement. .. note:: @@ -1986,8 +1923,7 @@ build. searched during the build as potential feature directories. Continuing with the example, suppose the "test.scc" feature you are - adding has a ``test.scc`` file in the following directory: - :: + adding has a ``test.scc`` file in the following directory:: my_recipe | @@ -2001,8 +1937,7 @@ build. a similarly named configuration fragment file ``test.cfg``. 2. *Add the Feature File to SRC_URI:* Add the ``.scc`` file to the - recipe's ``SRC_URI`` statement: - :: + recipe's :term:`SRC_URI` statement:: SRC_URI_append = " file://test.scc" @@ -2010,9 +1945,8 @@ build. appended to the existing path. 3. *Specify the Feature as a Kernel Feature:* Use the - ``KERNEL_FEATURES`` statement to specify the feature as a kernel - feature: - :: + :term:`KERNEL_FEATURES` statement to specify the feature as a kernel + feature:: KERNEL_FEATURES_append = " test.scc" |