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+*****
+Tasks
+*****
+
+Tasks are units of execution for BitBake. Recipes (``.bb`` files) use
+tasks to complete configuring, compiling, and packaging software. This
+chapter provides a reference of the tasks defined in the OpenEmbedded
+build system.
+
+Normal Recipe Build Tasks
+=========================
+
+The following sections describe normal tasks associated with building a
+recipe. For more information on tasks and dependencies, see the
+"`Tasks <&YOCTO_DOCS_BB_URL;#tasks>`__" and
+"`Dependencies <&YOCTO_DOCS_BB_URL;#dependencies>`__" sections in the
+BitBake User Manual.
+
+.. _ref-tasks-build:
+
+``do_build``
+------------
+
+The default task for all recipes. This task depends on all other normal
+tasks required to build a recipe.
+
+.. _ref-tasks-compile:
+
+``do_compile``
+--------------
+
+Compiles the source code. This task runs with the current working
+directory set to ``${``\ ```B`` <#var-B>`__\ ``}``.
+
+The default behavior of this task is to run the ``oe_runmake`` function
+if a makefile (``Makefile``, ``makefile``, or ``GNUmakefile``) is found.
+If no such file is found, the ``do_compile`` task does nothing.
+
+.. _ref-tasks-compile_ptest_base:
+
+``do_compile_ptest_base``
+-------------------------
+
+Compiles the runtime test suite included in the software being built.
+
+.. _ref-tasks-configure:
+
+``do_configure``
+----------------
+
+Configures the source by enabling and disabling any build-time and
+configuration options for the software being built. The task runs with
+the current working directory set to ``${``\ ```B`` <#var-B>`__\ ``}``.
+
+The default behavior of this task is to run ``oe_runmake clean`` if a
+makefile (``Makefile``, ``makefile``, or ``GNUmakefile``) is found and
+```CLEANBROKEN`` <#var-CLEANBROKEN>`__ is not set to "1". If no such
+file is found or the ``CLEANBROKEN`` variable is set to "1", the
+``do_configure`` task does nothing.
+
+.. _ref-tasks-configure_ptest_base:
+
+``do_configure_ptest_base``
+---------------------------
+
+Configures the runtime test suite included in the software being built.
+
+.. _ref-tasks-deploy:
+
+``do_deploy``
+-------------
+
+Writes output files that are to be deployed to
+``${``\ ```DEPLOY_DIR_IMAGE`` <#var-DEPLOY_DIR_IMAGE>`__\ ``}``. The
+task runs with the current working directory set to
+``${``\ ```B`` <#var-B>`__\ ``}``.
+
+Recipes implementing this task should inherit the
+```deploy`` <#ref-classes-deploy>`__ class and should write the output
+to ``${``\ ```DEPLOYDIR`` <#var-DEPLOYDIR>`__\ ``}``, which is not to be
+confused with ``${DEPLOY_DIR}``. The ``deploy`` class sets up
+``do_deploy`` as a shared state (sstate) task that can be accelerated
+through sstate use. The sstate mechanism takes care of copying the
+output from ``${DEPLOYDIR}`` to ``${DEPLOY_DIR_IMAGE}``.
+
+.. note::
+
+   Do not write the output directly to
+   ${DEPLOY_DIR_IMAGE}
+   , as this causes the sstate mechanism to malfunction.
+
+The ``do_deploy`` task is not added as a task by default and
+consequently needs to be added manually. If you want the task to run
+after ```do_compile`` <#ref-tasks-compile>`__, you can add it by doing
+the following: addtask deploy after do_compile Adding ``do_deploy``
+after other tasks works the same way.
+
+.. note::
+
+   You do not need to add
+   before do_build
+   to the
+   addtask
+   command (though it is harmless), because the
+   base
+   class contains the following:
+   ::
+
+           do_build[recrdeptask] += "do_deploy"
+                      
+
+   See the "
+   Dependencies
+   " section in the BitBake User Manual for more information.
+
+If the ``do_deploy`` task re-executes, any previous output is removed
+(i.e. "cleaned").
+
+.. _ref-tasks-fetch:
+
+``do_fetch``
+------------
+
+Fetches the source code. This task uses the
+```SRC_URI`` <#var-SRC_URI>`__ variable and the argument's prefix to
+determine the correct `fetcher <&YOCTO_DOCS_BB_URL;#bb-fetchers>`__
+module.
+
+.. _ref-tasks-image:
+
+``do_image``
+------------
+
+Starts the image generation process. The ``do_image`` task runs after
+the OpenEmbedded build system has run the
+```do_rootfs`` <#ref-tasks-rootfs>`__ task during which packages are
+identified for installation into the image and the root filesystem is
+created, complete with post-processing.
+
+The ``do_image`` task performs pre-processing on the image through the
+```IMAGE_PREPROCESS_COMMAND`` <#var-IMAGE_PREPROCESS_COMMAND>`__ and
+dynamically generates supporting ``do_image_*`` tasks as needed.
+
+For more information on image creation, see the "`Image
+Generation <&YOCTO_DOCS_OM_URL;#image-generation-dev-environment>`__"
+section in the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-image-complete:
+
+``do_image_complete``
+---------------------
+
+Completes the image generation process. The ``do_image_complete`` task
+runs after the OpenEmbedded build system has run the
+```do_image`` <#ref-tasks-image>`__ task during which image
+pre-processing occurs and through dynamically generated ``do_image_*``
+tasks the image is constructed.
+
+The ``do_image_complete`` task performs post-processing on the image
+through the
+```IMAGE_POSTPROCESS_COMMAND`` <#var-IMAGE_POSTPROCESS_COMMAND>`__.
+
+For more information on image creation, see the "`Image
+Generation <&YOCTO_DOCS_OM_URL;#image-generation-dev-environment>`__"
+section in the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-install:
+
+``do_install``
+--------------
+
+Copies files that are to be packaged into the holding area
+``${``\ ```D`` <#var-D>`__\ ``}``. This task runs with the current
+working directory set to ``${``\ ```B`` <#var-B>`__\ ``}``, which is the
+compilation directory. The ``do_install`` task, as well as other tasks
+that either directly or indirectly depend on the installed files (e.g.
+```do_package`` <#ref-tasks-package>`__,
+```do_package_write_*`` <#ref-tasks-package_write_deb>`__, and
+```do_rootfs`` <#ref-tasks-rootfs>`__), run under
+`fakeroot <&YOCTO_DOCS_OM_URL;#fakeroot-and-pseudo>`__.
+
+.. note::
+
+   When installing files, be careful not to set the owner and group IDs
+   of the installed files to unintended values. Some methods of copying
+   files, notably when using the recursive ``cp`` command, can preserve
+   the UID and/or GID of the original file, which is usually not what
+   you want. The
+   ```host-user-contaminated`` <#insane-host-user-contaminated>`__ QA
+   check checks for files that probably have the wrong ownership.
+
+   Safe methods for installing files include the following:
+
+   -  The ``install`` utility. This utility is the preferred method.
+
+   -  The ``cp`` command with the "--no-preserve=ownership" option.
+
+   -  The ``tar`` command with the "--no-same-owner" option. See the
+      ``bin_package.bbclass`` file in the ``meta/classes`` directory of
+      the `Source Directory <#source-directory>`__ for an example.
+
+.. _ref-tasks-install_ptest_base:
+
+``do_install_ptest_base``
+-------------------------
+
+Copies the runtime test suite files from the compilation directory to a
+holding area.
+
+.. _ref-tasks-package:
+
+``do_package``
+--------------
+
+Analyzes the content of the holding area
+``${``\ ```D`` <#var-D>`__\ ``}`` and splits the content into subsets
+based on available packages and files. This task makes use of the
+```PACKAGES`` <#var-PACKAGES>`__ and ```FILES`` <#var-FILES>`__
+variables.
+
+The ``do_package`` task, in conjunction with the
+```do_packagedata`` <#ref-tasks-packagedata>`__ task, also saves some
+important package metadata. For additional information, see the
+```PKGDESTWORK`` <#var-PKGDESTWORK>`__ variable and the "`Automatically
+Added Runtime
+Dependencies <&YOCTO_DOCS_OM_URL;#automatically-added-runtime-dependencies>`__"
+section in the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-package_qa:
+
+``do_package_qa``
+-----------------
+
+Runs QA checks on packaged files. For more information on these checks,
+see the ```insane`` <#ref-classes-insane>`__ class.
+
+.. _ref-tasks-package_write_deb:
+
+``do_package_write_deb``
+------------------------
+
+Creates Debian packages (i.e. ``*.deb`` files) and places them in the
+``${``\ ```DEPLOY_DIR_DEB`` <#var-DEPLOY_DIR_DEB>`__\ ``}`` directory in
+the package feeds area. For more information, see the "`Package
+Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section in
+the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-package_write_ipk:
+
+``do_package_write_ipk``
+------------------------
+
+Creates IPK packages (i.e. ``*.ipk`` files) and places them in the
+``${``\ ```DEPLOY_DIR_IPK`` <#var-DEPLOY_DIR_IPK>`__\ ``}`` directory in
+the package feeds area. For more information, see the "`Package
+Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section in
+the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-package_write_rpm:
+
+``do_package_write_rpm``
+------------------------
+
+Creates RPM packages (i.e. ``*.rpm`` files) and places them in the
+``${``\ ```DEPLOY_DIR_RPM`` <#var-DEPLOY_DIR_RPM>`__\ ``}`` directory in
+the package feeds area. For more information, see the "`Package
+Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section in
+the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-package_write_tar:
+
+``do_package_write_tar``
+------------------------
+
+Creates tarballs and places them in the
+``${``\ ```DEPLOY_DIR_TAR`` <#var-DEPLOY_DIR_TAR>`__\ ``}`` directory in
+the package feeds area. For more information, see the "`Package
+Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__" section in
+the Yocto Project Overview and Concepts Manual.
+
+.. _ref-tasks-packagedata:
+
+``do_packagedata``
+------------------
+
+Saves package metadata generated by the
+```do_package`` <#ref-tasks-package>`__ task in
+```PKGDATA_DIR`` <#var-PKGDATA_DIR>`__ to make it available globally.
+
+.. _ref-tasks-patch:
+
+``do_patch``
+------------
+
+Locates patch files and applies them to the source code.
+
+After fetching and unpacking source files, the build system uses the
+recipe's ```SRC_URI`` <&YOCTO_DOCS_REF_URL;#var-SRC_URI>`__ statements
+to locate and apply patch files to the source code.
+
+.. note::
+
+   The build system uses the
+   FILESPATH
+   variable to determine the default set of directories when searching
+   for patches.
+
+Patch files, by default, are ``*.patch`` and ``*.diff`` files created
+and kept in a subdirectory of the directory holding the recipe file. For
+example, consider the
+```bluez5`` <&YOCTO_GIT_URL;/cgit/cgit.cgi/poky/tree/meta/recipes-connectivity/bluez5>`__
+recipe from the OE-Core layer (i.e. ``poky/meta``):
+poky/meta/recipes-connectivity/bluez5 This recipe has two patch files
+located here: poky/meta/recipes-connectivity/bluez5/bluez5
+
+In the ``bluez5`` recipe, the ``SRC_URI`` statements point to the source
+and patch files needed to build the package.
+
+.. note::
+
+   In the case for the
+   bluez5_5.48.bb
+   recipe, the
+   SRC_URI
+   statements are from an include file
+   bluez5.inc
+   .
+
+As mentioned earlier, the build system treats files whose file types are
+``.patch`` and ``.diff`` as patch files. However, you can use the
+"apply=yes" parameter with the ``SRC_URI`` statement to indicate any
+file as a patch file: SRC_URI = " \\ git://path_to_repo/some_package \\
+file://file;apply=yes \\ "
+
+Conversely, if you have a directory full of patch files and you want to
+exclude some so that the ``do_patch`` task does not apply them during
+the patch phase, you can use the "apply=no" parameter with the
+``SRC_URI`` statement: SRC_URI = " \\ git://path_to_repo/some_package \\
+file://path_to_lots_of_patch_files \\
+file://path_to_lots_of_patch_files/patch_file5;apply=no \\ " In the
+previous example, assuming all the files in the directory holding the
+patch files end with either ``.patch`` or ``.diff``, every file would be
+applied as a patch by default except for the patch_file5 patch.
+
+You can find out more about the patching process in the
+"`Patching <&YOCTO_DOCS_OM_URL;#patching-dev-environment>`__" section in
+the Yocto Project Overview and Concepts Manual and the "`Patching
+Code <&YOCTO_DOCS_DEV_URL;#new-recipe-patching-code>`__" section in the
+Yocto Project Development Tasks Manual.
+
+.. _ref-tasks-populate_lic:
+
+``do_populate_lic``
+-------------------
+
+Writes license information for the recipe that is collected later when
+the image is constructed.
+
+.. _ref-tasks-populate_sdk:
+
+``do_populate_sdk``
+-------------------
+
+Creates the file and directory structure for an installable SDK. See the
+"`SDK
+Generation <&YOCTO_DOCS_OM_URL;#sdk-generation-dev-environment>`__"
+section in the Yocto Project Overview and Concepts Manual for more
+information.
+
+.. _ref-tasks-populate_sysroot:
+
+``do_populate_sysroot``
+-----------------------
+
+Stages (copies) a subset of the files installed by the
+```do_install`` <#ref-tasks-install>`__ task into the appropriate
+sysroot. For information on how to access these files from other
+recipes, see the ```STAGING_DIR*`` <#var-STAGING_DIR_HOST>`__ variables.
+Directories that would typically not be needed by other recipes at build
+time (e.g. ``/etc``) are not copied by default.
+
+For information on what directories are copied by default, see the
+```SYSROOT_DIRS*`` <#var-SYSROOT_DIRS>`__ variables. You can change
+these variables inside your recipe if you need to make additional (or
+fewer) directories available to other recipes at build time.
+
+The ``do_populate_sysroot`` task is a shared state (sstate) task, which
+means that the task can be accelerated through sstate use. Realize also
+that if the task is re-executed, any previous output is removed (i.e.
+"cleaned").
+
+.. _ref-tasks-prepare_recipe_sysroot:
+
+``do_prepare_recipe_sysroot``
+-----------------------------
+
+Installs the files into the individual recipe specific sysroots (i.e.
+``recipe-sysroot`` and ``recipe-sysroot-native`` under
+``${``\ ```WORKDIR`` <#var-WORKDIR>`__\ ``}`` based upon the
+dependencies specified by ```DEPENDS`` <#var-DEPENDS>`__). See the
+"```staging`` <#ref-classes-staging>`__" class for more information.
+
+.. _ref-tasks-rm_work:
+
+``do_rm_work``
+--------------
+
+Removes work files after the OpenEmbedded build system has finished with
+them. You can learn more by looking at the
+"```rm_work.bbclass`` <#ref-classes-rm-work>`__" section.
+
+.. _ref-tasks-unpack:
+
+``do_unpack``
+-------------
+
+Unpacks the source code into a working directory pointed to by
+``${``\ ```WORKDIR`` <#var-WORKDIR>`__\ ``}``. The ```S`` <#var-S>`__
+variable also plays a role in where unpacked source files ultimately
+reside. For more information on how source files are unpacked, see the
+"`Source
+Fetching <&YOCTO_DOCS_OM_URL;#source-fetching-dev-environment>`__"
+section in the Yocto Project Overview and Concepts Manual and also see
+the ``WORKDIR`` and ``S`` variable descriptions.
+
+Manually Called Tasks
+=====================
+
+These tasks are typically manually triggered (e.g. by using the
+``bitbake -c`` command-line option):
+
+.. _ref-tasks-checkpkg:
+
+``do_checkpkg``
+---------------
+
+Provides information about the recipe including its upstream version and
+status. The upstream version and status reveals whether or not a version
+of the recipe exists upstream and a status of not updated, updated, or
+unknown.
+
+To check the upstream version and status of a recipe, use the following
+devtool commands: $ devtool latest-version $ devtool
+check-upgrade-status See the "```devtool`` Quick
+Reference <#ref-devtool-reference>`__" chapter for more information on
+``devtool``. See the "`Checking on the Upgrade Status of a
+Recipe <&YOCTO_DOCS_REF_URL;#devtool-checking-on-the-upgrade-status-of-a-recipe>`__"
+section for information on checking the upgrade status of a recipe.
+
+To build the ``checkpkg`` task, use the ``bitbake`` command with the
+"-c" option and task name: $ bitbake core-image-minimal -c checkpkg By
+default, the results are stored in ```$LOG_DIR`` <#var-LOG_DIR>`__ (e.g.
+``$BUILD_DIR/tmp/log``).
+
+.. _ref-tasks-checkuri:
+
+``do_checkuri``
+---------------
+
+Validates the ```SRC_URI`` <#var-SRC_URI>`__ value.
+
+.. _ref-tasks-clean:
+
+``do_clean``
+------------
+
+Removes all output files for a target from the
+```do_unpack`` <#ref-tasks-unpack>`__ task forward (i.e. ``do_unpack``,
+```do_configure`` <#ref-tasks-configure>`__,
+```do_compile`` <#ref-tasks-compile>`__,
+```do_install`` <#ref-tasks-install>`__, and
+```do_package`` <#ref-tasks-package>`__).
+
+You can run this task using BitBake as follows: $ bitbake -c clean
+recipe
+
+Running this task does not remove the
+`sstate <&YOCTO_DOCS_OM_URL;#shared-state-cache>`__ cache files.
+Consequently, if no changes have been made and the recipe is rebuilt
+after cleaning, output files are simply restored from the sstate cache.
+If you want to remove the sstate cache files for the recipe, you need to
+use the ```do_cleansstate`` <#ref-tasks-cleansstate>`__ task instead
+(i.e. ``bitbake -c cleansstate`` recipe).
+
+.. _ref-tasks-cleanall:
+
+``do_cleanall``
+---------------
+
+Removes all output files, shared state
+(`sstate <&YOCTO_DOCS_OM_URL;#shared-state-cache>`__) cache, and
+downloaded source files for a target (i.e. the contents of
+```DL_DIR`` <#var-DL_DIR>`__). Essentially, the ``do_cleanall`` task is
+identical to the ```do_cleansstate`` <#ref-tasks-cleansstate>`__ task
+with the added removal of downloaded source files.
+
+You can run this task using BitBake as follows: $ bitbake -c cleanall
+recipe
+
+Typically, you would not normally use the ``cleanall`` task. Do so only
+if you want to start fresh with the ```do_fetch`` <#ref-tasks-fetch>`__
+task.
+
+.. _ref-tasks-cleansstate:
+
+``do_cleansstate``
+------------------
+
+Removes all output files and shared state
+(`sstate <&YOCTO_DOCS_OM_URL;#shared-state-cache>`__) cache for a
+target. Essentially, the ``do_cleansstate`` task is identical to the
+```do_clean`` <#ref-tasks-clean>`__ task with the added removal of
+shared state (`sstate <&YOCTO_DOCS_OM_URL;#shared-state-cache>`__)
+cache.
+
+You can run this task using BitBake as follows: $ bitbake -c cleansstate
+recipe
+
+When you run the ``do_cleansstate`` task, the OpenEmbedded build system
+no longer uses any sstate. Consequently, building the recipe from
+scratch is guaranteed.
+
+.. note::
+
+   The
+   do_cleansstate
+   task cannot remove sstate from a remote sstate mirror. If you need to
+   build a target from scratch using remote mirrors, use the "-f" option
+   as follows:
+   ::
+
+           $ bitbake -f -c do_cleansstate target
+                      
+
+.. _ref-tasks-devpyshell:
+
+``do_devpyshell``
+-----------------
+
+Starts a shell in which an interactive Python interpreter allows you to
+interact with the BitBake build environment. From within this shell, you
+can directly examine and set bits from the data store and execute
+functions as if within the BitBake environment. See the "`Using a
+Development Python
+Shell <&YOCTO_DOCS_DEV_URL;#platdev-appdev-devpyshell>`__" section in
+the Yocto Project Development Tasks Manual for more information about
+using ``devpyshell``.
+
+.. _ref-tasks-devshell:
+
+``do_devshell``
+---------------
+
+Starts a shell whose environment is set up for development, debugging,
+or both. See the "`Using a Development
+Shell <&YOCTO_DOCS_DEV_URL;#platdev-appdev-devshell>`__" section in the
+Yocto Project Development Tasks Manual for more information about using
+``devshell``.
+
+.. _ref-tasks-listtasks:
+
+``do_listtasks``
+----------------
+
+Lists all defined tasks for a target.
+
+.. _ref-tasks-package_index:
+
+``do_package_index``
+--------------------
+
+Creates or updates the index in the `Package
+Feeds <&YOCTO_DOCS_OM_URL;#package-feeds-dev-environment>`__ area.
+
+.. note::
+
+   This task is not triggered with the
+   bitbake -c
+   command-line option as are the other tasks in this section. Because
+   this task is specifically for the
+   package-index
+   recipe, you run it using
+   bitbake package-index
+   .
+
+Image-Related Tasks
+===================
+
+The following tasks are applicable to image recipes.
+
+.. _ref-tasks-bootimg:
+
+``do_bootimg``
+--------------
+
+Creates a bootable live image. See the
+```IMAGE_FSTYPES`` <#var-IMAGE_FSTYPES>`__ variable for additional
+information on live image types.
+
+.. _ref-tasks-bundle_initramfs:
+
+``do_bundle_initramfs``
+-----------------------
+
+Combines an initial RAM disk (initramfs) image and kernel together to
+form a single image. The
+```CONFIG_INITRAMFS_SOURCE`` <#var-CONFIG_INITRAMFS_SOURCE>`__ variable
+has some more information about these types of images.
+
+.. _ref-tasks-rootfs:
+
+``do_rootfs``
+-------------
+
+Creates the root filesystem (file and directory structure) for an image.
+See the "`Image
+Generation <&YOCTO_DOCS_OM_URL;#image-generation-dev-environment>`__"
+section in the Yocto Project Overview and Concepts Manual for more
+information on how the root filesystem is created.
+
+.. _ref-tasks-testimage:
+
+``do_testimage``
+----------------
+
+Boots an image and performs runtime tests within the image. For
+information on automatically testing images, see the "`Performing
+Automated Runtime
+Testing <&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing>`__"
+section in the Yocto Project Development Tasks Manual.
+
+.. _ref-tasks-testimage_auto:
+
+``do_testimage_auto``
+---------------------
+
+Boots an image and performs runtime tests within the image immediately
+after it has been built. This task is enabled when you set
+```TESTIMAGE_AUTO`` <#var-TESTIMAGE_AUTO>`__ equal to "1".
+
+For information on automatically testing images, see the "`Performing
+Automated Runtime
+Testing <&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing>`__"
+section in the Yocto Project Development Tasks Manual.
+
+Kernel-Related Tasks
+====================
+
+The following tasks are applicable to kernel recipes. Some of these
+tasks (e.g. the ```do_menuconfig`` <#ref-tasks-menuconfig>`__ task) are
+also applicable to recipes that use Linux kernel style configuration
+such as the BusyBox recipe.
+
+.. _ref-tasks-compile_kernelmodules:
+
+``do_compile_kernelmodules``
+----------------------------
+
+Runs the step that builds the kernel modules (if needed). Building a
+kernel consists of two steps: 1) the kernel (``vmlinux``) is built, and
+2) the modules are built (i.e. ``make modules``).
+
+.. _ref-tasks-diffconfig:
+
+``do_diffconfig``
+-----------------
+
+When invoked by the user, this task creates a file containing the
+differences between the original config as produced by
+```do_kernel_configme`` <#ref-tasks-kernel_configme>`__ task and the
+changes made by the user with other methods (i.e. using
+(```do_kernel_menuconfig`` <#ref-tasks-kernel_menuconfig>`__). Once the
+file of differences is created, it can be used to create a config
+fragment that only contains the differences. You can invoke this task
+from the command line as follows: $ bitbake linux-yocto -c diffconfig
+For more information, see the "`Creating Configuration
+Fragments <&YOCTO_DOCS_KERNEL_DEV_URL;#creating-config-fragments>`__"
+section in the Yocto Project Linux Kernel Development Manual.
+
+.. _ref-tasks-kernel_checkout:
+
+``do_kernel_checkout``
+----------------------
+
+Converts the newly unpacked kernel source into a form with which the
+OpenEmbedded build system can work. Because the kernel source can be
+fetched in several different ways, the ``do_kernel_checkout`` task makes
+sure that subsequent tasks are given a clean working tree copy of the
+kernel with the correct branches checked out.
+
+.. _ref-tasks-kernel_configcheck:
+
+``do_kernel_configcheck``
+-------------------------
+
+Validates the configuration produced by the
+```do_kernel_menuconfig`` <#ref-tasks-kernel_menuconfig>`__ task. The
+``do_kernel_configcheck`` task produces warnings when a requested
+configuration does not appear in the final ``.config`` file or when you
+override a policy configuration in a hardware configuration fragment.
+You can run this task explicitly and view the output by using the
+following command: $ bitbake linux-yocto -c kernel_configcheck -f For
+more information, see the "`Validating
+Configuration <&YOCTO_DOCS_KERNEL_DEV_URL;#validating-configuration>`__"
+section in the Yocto Project Linux Kernel Development Manual.
+
+.. _ref-tasks-kernel_configme:
+
+``do_kernel_configme``
+----------------------
+
+After the kernel is patched by the ```do_patch`` <#ref-tasks-patch>`__
+task, the ``do_kernel_configme`` task assembles and merges all the
+kernel config fragments into a merged configuration that can then be
+passed to the kernel configuration phase proper. This is also the time
+during which user-specified defconfigs are applied if present, and where
+configuration modes such as ``--allnoconfig`` are applied.
+
+.. _ref-tasks-kernel_menuconfig:
+
+``do_kernel_menuconfig``
+------------------------
+
+Invoked by the user to manipulate the ``.config`` file used to build a
+linux-yocto recipe. This task starts the Linux kernel configuration
+tool, which you then use to modify the kernel configuration.
+
+.. note::
+
+   You can also invoke this tool from the command line as follows:
+   ::
+
+           $ bitbake linux-yocto -c menuconfig
+                      
+
+See the "`Using
+``menuconfig`` <&YOCTO_DOCS_KERNEL_DEV_URL;#using-menuconfig>`__"
+section in the Yocto Project Linux Kernel Development Manual for more
+information on this configuration tool.
+
+.. _ref-tasks-kernel_metadata:
+
+``do_kernel_metadata``
+----------------------
+
+Collects all the features required for a given kernel build, whether the
+features come from ```SRC_URI`` <#var-SRC_URI>`__ or from Git
+repositories. After collection, the ``do_kernel_metadata`` task
+processes the features into a series of config fragments and patches,
+which can then be applied by subsequent tasks such as
+```do_patch`` <#ref-tasks-patch>`__ and
+```do_kernel_configme`` <#ref-tasks-kernel_configme>`__.
+
+.. _ref-tasks-menuconfig:
+
+``do_menuconfig``
+-----------------
+
+Runs ``make menuconfig`` for the kernel. For information on
+``menuconfig``, see the
+"`Using  ``menuconfig`` <&YOCTO_DOCS_KERNEL_DEV_URL;#using-menuconfig>`__"
+section in the Yocto Project Linux Kernel Development Manual.
+
+.. _ref-tasks-savedefconfig:
+
+``do_savedefconfig``
+--------------------
+
+When invoked by the user, creates a defconfig file that can be used
+instead of the default defconfig. The saved defconfig contains the
+differences between the default defconfig and the changes made by the
+user using other methods (i.e. the
+```do_kernel_menuconfig`` <#ref-tasks-kernel_menuconfig>`__ task. You
+can invoke the task using the following command: $ bitbake linux-yocto
+-c savedefconfig
+
+.. _ref-tasks-shared_workdir:
+
+``do_shared_workdir``
+---------------------
+
+After the kernel has been compiled but before the kernel modules have
+been compiled, this task copies files required for module builds and
+which are generated from the kernel build into the shared work
+directory. With these copies successfully copied, the
+```do_compile_kernelmodules`` <#ref-tasks-compile_kernelmodules>`__ task
+can successfully build the kernel modules in the next step of the build.
+
+.. _ref-tasks-sizecheck:
+
+``do_sizecheck``
+----------------
+
+After the kernel has been built, this task checks the size of the
+stripped kernel image against
+```KERNEL_IMAGE_MAXSIZE`` <#var-KERNEL_IMAGE_MAXSIZE>`__. If that
+variable was set and the size of the stripped kernel exceeds that size,
+the kernel build produces a warning to that effect.
+
+.. _ref-tasks-strip:
+
+``do_strip``
+------------
+
+If ``KERNEL_IMAGE_STRIP_EXTRA_SECTIONS`` is defined, this task strips
+the sections named in that variable from ``vmlinux``. This stripping is
+typically used to remove nonessential sections such as ``.comment``
+sections from a size-sensitive configuration.
+
+.. _ref-tasks-validate_branches:
+
+``do_validate_branches``
+------------------------
+
+After the kernel is unpacked but before it is patched, this task makes
+sure that the machine and metadata branches as specified by the
+```SRCREV`` <#var-SRCREV>`__ variables actually exist on the specified
+branches. If these branches do not exist and
+```AUTOREV`` <#var-AUTOREV>`__ is not being used, the
+``do_validate_branches`` task fails during the build.
+
+Miscellaneous Tasks
+===================
+
+The following sections describe miscellaneous tasks.
+
+.. _ref-tasks-spdx:
+
+``do_spdx``
+-----------
+
+A build stage that takes the source code and scans it on a remote
+FOSSOLOGY server in order to produce an SPDX document. This task applies
+only to the ```spdx`` <#ref-classes-spdx>`__ class.