diff --git a/poky/documentation/kernel-dev/history.rst b/poky/documentation/kernel-dev/history.rst
index 761b506..3ffb7ea 100644
--- a/poky/documentation/kernel-dev/history.rst
+++ b/poky/documentation/kernel-dev/history.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 ***********************
 Manual Revision History
diff --git a/poky/documentation/kernel-dev/kernel-dev-advanced.rst b/poky/documentation/kernel-dev/kernel-dev-advanced.rst
index eeb8f87..36133ca 100644
--- a/poky/documentation/kernel-dev/kernel-dev-advanced.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-advanced.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 *******************************************************
 Working with Advanced Metadata (``yocto-kernel-cache``)
diff --git a/poky/documentation/kernel-dev/kernel-dev-advanced.xml b/poky/documentation/kernel-dev/kernel-dev-advanced.xml
new file mode 100644
index 0000000..3717796
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-advanced.xml
@@ -0,0 +1,1257 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='kernel-dev-advanced'>
+<title>Working with Advanced Metadata (<filename>yocto-kernel-cache</filename>)</title>
+
+<section id='kernel-dev-advanced-overview'>
+    <title>Overview</title>
+
+    <para>
+        In addition to supporting configuration fragments and patches, the
+        Yocto Project kernel tools also support rich
+        <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink> that you can
+        use to define complex policies and Board Support Package (BSP) support.
+        The purpose of the Metadata and the tools that manage it is
+        to help you manage the complexity of the configuration and sources
+        used to support multiple BSPs and Linux kernel types.
+    </para>
+
+    <para>
+        Kernel Metadata exists in many places.
+        One area in the Yocto Project
+        <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+        is the <filename>yocto-kernel-cache</filename> Git repository.
+        You can find this repository grouped under the "Yocto Linux Kernel"
+        heading in the
+        <ulink url='&YOCTO_GIT_URL;'>Yocto Project Source Repositories</ulink>.
+    </para>
+
+    <para>
+        Kernel development tools ("kern-tools") exist also in the Yocto
+        Project Source Repositories under the "Yocto Linux Kernel" heading
+        in the <filename>yocto-kernel-tools</filename> Git repository.
+        The recipe that builds these tools is
+        <filename>meta/recipes-kernel/kern-tools/kern-tools-native_git.bb</filename>
+        in the
+        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+        (e.g. <filename>poky</filename>).
+    </para>
+</section>
+
+<section id='using-kernel-metadata-in-a-recipe'>
+    <title>Using Kernel Metadata in a Recipe</title>
+
+    <para>
+        As mentioned in the introduction, the Yocto Project contains kernel
+        Metadata, which is located in the
+        <filename>yocto-kernel-cache</filename> Git repository.
+        This Metadata defines Board Support Packages (BSPs) that
+        correspond to definitions in linux-yocto recipes for corresponding BSPs.
+        A BSP consists of an aggregation of kernel policy and enabled
+        hardware-specific features.
+        The BSP can be influenced from within the linux-yocto recipe.
+        <note>
+            A Linux kernel recipe that contains kernel Metadata (e.g.
+            inherits from the <filename>linux-yocto.inc</filename> file)
+            is said to be a "linux-yocto style" recipe.
+        </note>
+    </para>
+
+    <para>
+        Every linux-yocto style recipe must define the
+        <ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>
+        variable.
+        This variable is typically set to the same value as the
+        <filename>MACHINE</filename> variable, which is used by
+        <ulink url='&YOCTO_DOCS_REF_URL;#bitbake-term'>BitBake</ulink>.
+        However, in some cases, the variable might instead refer to the
+        underlying platform of the <filename>MACHINE</filename>.
+    </para>
+
+    <para>
+        Multiple BSPs can reuse the same <filename>KMACHINE</filename>
+        name if they are built using the same BSP description.
+        Multiple Corei7-based BSPs could share the same "intel-corei7-64"
+        value for <filename>KMACHINE</filename>.
+        It is important to realize that <filename>KMACHINE</filename> is
+        just for kernel mapping, while <filename>MACHINE</filename>
+        is the machine type within a BSP Layer.
+        Even with this distinction, however, these two variables can hold
+        the same value.
+        See the <link linkend='bsp-descriptions'>BSP Descriptions</link>
+        section for more information.
+    </para>
+
+    <para>
+        Every linux-yocto style recipe must also indicate the Linux kernel
+        source repository branch used to build the Linux kernel.
+        The <ulink url='&YOCTO_DOCS_REF_URL;#var-KBRANCH'><filename>KBRANCH</filename></ulink>
+        variable must be set to indicate the branch.
+        <note>
+            You can use the <filename>KBRANCH</filename> value to define an
+            alternate branch typically with a machine override as shown here
+            from the <filename>meta-yocto-bsp</filename> layer:
+            <literallayout class='monospaced'>
+     KBRANCH_edgerouter = "standard/edgerouter"
+            </literallayout>
+        </note>
+    </para>
+
+    <para>
+        The linux-yocto style recipes can optionally define the following
+        variables:
+        <literallayout class='monospaced'>
+     KERNEL_FEATURES
+     LINUX_KERNEL_TYPE
+        </literallayout>
+    </para>
+
+    <para>
+        <ulink url='&YOCTO_DOCS_REF_URL;#var-LINUX_KERNEL_TYPE'><filename>LINUX_KERNEL_TYPE</filename></ulink>
+        defines the kernel type to be
+        used in assembling the configuration.
+        If you do not specify a <filename>LINUX_KERNEL_TYPE</filename>,
+        it defaults to "standard".
+        Together with <filename>KMACHINE</filename>,
+        <filename>LINUX_KERNEL_TYPE</filename> defines the search
+        arguments used by the kernel tools to find the
+        appropriate description within the kernel Metadata with which to
+        build out the sources and configuration.
+        The linux-yocto recipes define "standard", "tiny", and "preempt-rt"
+        kernel types.
+        See the "<link linkend='kernel-types'>Kernel Types</link>" section
+        for more information on kernel types.
+    </para>
+
+    <para>
+        During the build, the kern-tools search for the BSP description
+        file that most closely matches the <filename>KMACHINE</filename>
+        and <filename>LINUX_KERNEL_TYPE</filename> variables passed in from the
+        recipe.
+        The tools use the first BSP description it finds that match
+        both variables.
+        If the tools cannot find a match, they issue a warning.
+    </para>
+
+    <para>
+        The tools first search for the <filename>KMACHINE</filename> and
+        then for the <filename>LINUX_KERNEL_TYPE</filename>.
+        If the tools cannot find a partial match, they will use the
+        sources from the <filename>KBRANCH</filename> and any configuration
+        specified in the
+        <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>.
+    </para>
+
+    <para>
+        You can use the
+        <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_FEATURES'><filename>KERNEL_FEATURES</filename></ulink>
+        variable
+        to include features (configuration fragments, patches, or both) that
+        are not already included by the <filename>KMACHINE</filename> and
+        <filename>LINUX_KERNEL_TYPE</filename> variable combination.
+        For example, to include a feature specified as
+        "features/netfilter/netfilter.scc",
+        specify:
+        <literallayout class='monospaced'>
+     KERNEL_FEATURES += "features/netfilter/netfilter.scc"
+        </literallayout>
+        To include a feature called "cfg/sound.scc" just for the
+        <filename>qemux86</filename> machine, specify:
+        <literallayout class='monospaced'>
+     KERNEL_FEATURES_append_qemux86 = " cfg/sound.scc"
+        </literallayout>
+        The value of the entries in <filename>KERNEL_FEATURES</filename>
+        are dependent on their location within the kernel Metadata itself.
+        The examples here are taken from the
+        <filename>yocto-kernel-cache</filename> repository.
+        Each branch of this repository contains "features" and "cfg"
+        subdirectories at the top-level.
+        For more information, see the
+        "<link linkend='kernel-metadata-syntax'>Kernel Metadata Syntax</link>"
+        section.
+    </para>
+</section>
+
+<section id='kernel-metadata-syntax'>
+    <title>Kernel Metadata Syntax</title>
+
+    <para>
+        The kernel Metadata consists of three primary types of files:
+        <filename>scc</filename>
+        <footnote>
+            <para>
+                <filename>scc</filename> stands for Series Configuration
+                Control, but the naming has less significance in the
+                current implementation of the tooling than it had in the
+                past.
+                Consider <filename>scc</filename> files to be description files.
+            </para>
+        </footnote>
+        description files, configuration fragments, and patches.
+        The <filename>scc</filename> files define variables and include or
+        otherwise reference any of the three file types.
+        The description files are used to aggregate all types of kernel
+        Metadata into
+        what ultimately describes the sources and the configuration required
+        to build a Linux kernel tailored to a specific machine.
+    </para>
+
+    <para>
+        The <filename>scc</filename> description files are used to define two
+        fundamental types of kernel Metadata:
+        <itemizedlist>
+            <listitem><para>Features</para></listitem>
+            <listitem><para>Board Support Packages (BSPs)</para></listitem>
+        </itemizedlist>
+    </para>
+
+    <para>
+        Features aggregate sources in the form of patches and configuration
+        fragments into a modular reusable unit.
+        You can use features to implement conceptually separate kernel
+        Metadata descriptions such as pure configuration fragments,
+        simple patches, complex features, and kernel types.
+        <link linkend='kernel-types'>Kernel types</link> define general
+        kernel features and policy to be reused in the BSPs.
+    </para>
+
+    <para>
+        BSPs define hardware-specific features and aggregate them with kernel
+        types to form the final description of what will be assembled and built.
+    </para>
+
+    <para>
+        While the kernel Metadata syntax does not enforce any logical
+        separation of configuration fragments, patches, features or kernel
+        types, best practices dictate a logical separation of these types
+        of Metadata.
+        The following Metadata file hierarchy is recommended:
+        <literallayout class='monospaced'>
+     <replaceable>base</replaceable>/
+        bsp/
+        cfg/
+        features/
+        ktypes/
+        patches/
+        </literallayout>
+    </para>
+
+    <para>
+        The <filename>bsp</filename> directory contains the
+        <link linkend='bsp-descriptions'>BSP descriptions</link>.
+        The remaining directories all contain "features".
+        Separating <filename>bsp</filename> from the rest of the structure
+        aids conceptualizing intended usage.
+    </para>
+
+    <para>
+        Use these guidelines to help place your <filename>scc</filename>
+        description files within the structure:
+        <itemizedlist>
+            <listitem><para>If your file contains
+                only configuration fragments, place the file in the
+                <filename>cfg</filename> directory.</para></listitem>
+            <listitem><para>If your file contains
+                only source-code fixes, place the file in the
+                <filename>patches</filename> directory.</para></listitem>
+            <listitem><para>If your file encapsulates
+                a major feature, often combining sources and configurations,
+                place the file in <filename>features</filename> directory.
+                </para></listitem>
+            <listitem><para>If your file aggregates
+                non-hardware configuration and patches in order to define a
+                base kernel policy or major kernel type to be reused across
+                multiple BSPs, place the file in <filename>ktypes</filename>
+                directory.
+                </para></listitem>
+        </itemizedlist>
+    </para>
+
+    <para>
+        These distinctions can easily become blurred - especially as
+        out-of-tree features slowly merge upstream over time.
+        Also, remember that how the description files are placed is
+        a purely logical organization and has no impact on the functionality
+        of the kernel Metadata.
+        There is no impact because all of <filename>cfg</filename>,
+        <filename>features</filename>, <filename>patches</filename>, and
+        <filename>ktypes</filename>, contain "features" as far as the kernel
+        tools are concerned.
+    </para>
+
+    <para>
+        Paths used in kernel Metadata files are relative to
+        <replaceable>base</replaceable>, which is either
+        <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+        if you are creating Metadata in
+        <link linkend='recipe-space-metadata'>recipe-space</link>,
+        or the top level of
+        <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/yocto-kernel-cache/tree/'><filename>yocto-kernel-cache</filename></ulink>
+        if you are creating
+        <link linkend='metadata-outside-the-recipe-space'>Metadata outside of the recipe-space</link>.
+    </para>
+
+    <section id='configuration'>
+        <title>Configuration</title>
+
+        <para>
+            The simplest unit of kernel Metadata is the configuration-only
+            feature.
+            This feature consists of one or more Linux kernel configuration
+            parameters in a configuration fragment file
+            (<filename>.cfg</filename>) and a <filename>.scc</filename> file
+            that describes the fragment.
+        </para>
+
+        <para>
+            As an example, consider the Symmetric Multi-Processing (SMP)
+            fragment used with the <filename>linux-yocto-4.12</filename>
+            kernel as defined outside of the recipe space (i.e.
+            <filename>yocto-kernel-cache</filename>).
+            This Metadata consists of two files: <filename>smp.scc</filename>
+            and <filename>smp.cfg</filename>.
+            You can find these files in the <filename>cfg</filename> directory
+            of the <filename>yocto-4.12</filename> branch in the
+            <filename>yocto-kernel-cache</filename> Git repository:
+            <literallayout class='monospaced'>
+     cfg/smp.scc:
+        define KFEATURE_DESCRIPTION "Enable SMP for 32 bit builds"
+        define KFEATURE_COMPATIBILITY all
+
+        kconf hardware smp.cfg
+
+     cfg/smp.cfg:
+        CONFIG_SMP=y
+        CONFIG_SCHED_SMT=y
+        # Increase default NR_CPUS from 8 to 64 so that platform with
+        # more than 8 processors can be all activated at boot time
+        CONFIG_NR_CPUS=64
+        # The following is needed when setting NR_CPUS to something
+        # greater than 8 on x86 architectures, it should be automatically
+        # disregarded by Kconfig when using a different arch
+        CONFIG_X86_BIGSMP=y
+            </literallayout>
+            You can find general information on configuration fragment files in
+            the
+            "<link linkend='creating-config-fragments'>Creating Configuration Fragments</link>"
+            section.
+        </para>
+
+        <para>
+            Within the <filename>smp.scc</filename> file, the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-KFEATURE_DESCRIPTION'><filename>KFEATURE_DESCRIPTION</filename></ulink>
+            statement provides a short description of the fragment.
+            Higher level kernel tools use this description.
+        </para>
+
+        <para>
+            Also within the <filename>smp.scc</filename> file, the
+            <filename>kconf</filename> command includes the
+            actual configuration fragment in an <filename>.scc</filename>
+            file, and the "hardware" keyword identifies the fragment as
+            being hardware enabling, as opposed to general policy,
+            which would use the "non-hardware" keyword.
+            The distinction is made for the benefit of the configuration
+            validation tools, which warn you if a hardware fragment
+            overrides a policy set by a non-hardware fragment.
+            <note>
+                The description file can include multiple
+                <filename>kconf</filename> statements, one per fragment.
+            </note>
+        </para>
+
+        <para>
+            As described in the
+            "<link linkend='validating-configuration'>Validating Configuration</link>"
+            section, you can use the following BitBake command to audit your
+            configuration:
+            <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c kernel_configcheck -f
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='patches'>
+        <title>Patches</title>
+
+        <para>
+            Patch descriptions are very similar to configuration fragment
+            descriptions, which are described in the previous section.
+            However, instead of a <filename>.cfg</filename> file, these
+            descriptions work with source patches (i.e.
+            <filename>.patch</filename> files).
+        </para>
+
+        <para>
+            A typical patch includes a description file and the patch itself.
+            As an example, consider the build patches used with the
+            <filename>linux-yocto-4.12</filename> kernel as defined outside of
+            the recipe space (i.e. <filename>yocto-kernel-cache</filename>).
+            This Metadata consists of several files:
+            <filename>build.scc</filename> and a set of
+            <filename>*.patch</filename> files.
+            You can find these files in the <filename>patches/build</filename>
+            directory of the <filename>yocto-4.12</filename> branch in the
+            <filename>yocto-kernel-cache</filename> Git repository.
+        </para>
+
+        <para>
+            The following listings show the <filename>build.scc</filename>
+            file and part of the
+            <filename>modpost-mask-trivial-warnings.patch</filename> file:
+            <literallayout class='monospaced'>
+     patches/build/build.scc:
+        patch arm-serialize-build-targets.patch
+        patch powerpc-serialize-image-targets.patch
+        patch kbuild-exclude-meta-directory-from-distclean-processi.patch
+
+        # applied by kgit
+        # patch kbuild-add-meta-files-to-the-ignore-li.patch
+
+        patch modpost-mask-trivial-warnings.patch
+        patch menuconfig-check-lxdiaglog.sh-Allow-specification-of.patch
+
+     patches/build/modpost-mask-trivial-warnings.patch:
+        From bd48931bc142bdd104668f3a062a1f22600aae61 Mon Sep 17 00:00:00 2001
+        From: Paul Gortmaker &lt;paul.gortmaker@windriver.com&gt;
+        Date: Sun, 25 Jan 2009 17:58:09 -0500
+        Subject: [PATCH] modpost: mask trivial warnings
+
+        Newer HOSTCC will complain about various stdio fcns because
+                          .
+                          .
+                          .
+ 	        char *dump_write = NULL, *files_source = NULL;
+ 	        int opt;
+        --
+        2.10.1
+
+        generated by cgit v0.10.2 at 2017-09-28 15:23:23 (GMT)
+            </literallayout>
+            The description file can include multiple patch statements where
+            each statement handles a single patch.
+            In the example <filename>build.scc</filename> file, five patch
+            statements exist for the five patches in the directory.
+        </para>
+
+        <para>
+            You can create a typical <filename>.patch</filename> file using
+            <filename>diff -Nurp</filename> or
+            <filename>git format-patch</filename> commands.
+            For information on how to create patches, see the
+            "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+            and
+            "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+            sections.
+        </para>
+    </section>
+
+    <section id='features'>
+        <title>Features</title>
+
+        <para>
+            Features are complex kernel Metadata types that consist
+            of configuration fragments, patches, and possibly other feature
+            description files.
+            As an example, consider the following generic listing:
+            <literallayout class='monospaced'>
+     features/<replaceable>myfeature</replaceable>.scc
+        define KFEATURE_DESCRIPTION "Enable <replaceable>myfeature</replaceable>"
+
+        patch 0001-<replaceable>myfeature</replaceable>-core.patch
+        patch 0002-<replaceable>myfeature</replaceable>-interface.patch
+
+        include cfg/<replaceable>myfeature</replaceable>_dependency.scc
+        kconf non-hardware <replaceable>myfeature</replaceable>.cfg
+            </literallayout>
+            This example shows how the <filename>patch</filename> and
+            <filename>kconf</filename> commands are used as well as
+            how an additional feature description file is included with
+            the <filename>include</filename> command.
+        </para>
+
+        <para>
+            Typically, features are less granular than configuration
+            fragments and are more likely than configuration fragments
+            and patches to be the types of things you want to specify
+            in the <filename>KERNEL_FEATURES</filename> variable of the
+            Linux kernel recipe.
+            See the "<link linkend='using-kernel-metadata-in-a-recipe'>Using Kernel Metadata in a Recipe</link>"
+            section earlier in the manual.
+        </para>
+    </section>
+
+    <section id='kernel-types'>
+        <title>Kernel Types</title>
+
+        <para>
+            A kernel type defines a high-level kernel policy by
+            aggregating non-hardware configuration fragments with
+            patches you want to use when building a Linux kernel of a
+            specific type (e.g. a real-time kernel).
+            Syntactically, kernel types are no different than features
+            as described in the "<link linkend='features'>Features</link>"
+            section.
+            The
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-LINUX_KERNEL_TYPE'><filename>LINUX_KERNEL_TYPE</filename></ulink>
+            variable in the kernel recipe selects the kernel type.
+            For example, in the <filename>linux-yocto_4.12.bb</filename>
+            kernel recipe found in
+            <filename>poky/meta/recipes-kernel/linux</filename>, a
+            <ulink url='&YOCTO_DOCS_BB_URL;#require-inclusion'><filename>require</filename></ulink>
+            directive includes the
+            <filename>poky/meta/recipes-kernel/linux/linux-yocto.inc</filename>
+            file, which has the following statement that defines the default
+            kernel type:
+            <literallayout class='monospaced'>
+     LINUX_KERNEL_TYPE ??= "standard"
+            </literallayout>
+        </para>
+
+        <para>
+            Another example would be the real-time kernel (i.e.
+            <filename>linux-yocto-rt_4.12.bb</filename>).
+            This kernel recipe directly sets the kernel type as follows:
+            <literallayout class='monospaced'>
+     LINUX_KERNEL_TYPE = "preempt-rt"
+            </literallayout>
+            <note>
+                You can find kernel recipes in the
+                <filename>meta/recipes-kernel/linux</filename> directory of the
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                (e.g. <filename>poky/meta/recipes-kernel/linux/linux-yocto_4.12.bb</filename>).
+                See the "<link linkend='using-kernel-metadata-in-a-recipe'>Using Kernel Metadata in a Recipe</link>"
+                section for more information.
+            </note>
+        </para>
+
+        <para>
+            Three kernel types ("standard", "tiny", and "preempt-rt") are
+            supported for Linux Yocto kernels:
+            <itemizedlist>
+                <listitem><para>"standard":
+                    Includes the generic Linux kernel policy of the Yocto
+                    Project linux-yocto kernel recipes.
+                    This policy includes, among other things, which file
+                    systems, networking options, core kernel features, and
+                    debugging and tracing options are supported.
+                    </para></listitem>
+                <listitem><para>"preempt-rt":
+                    Applies the <filename>PREEMPT_RT</filename>
+                    patches and the configuration options required to
+                    build a real-time Linux kernel.
+                    This kernel type inherits from the "standard" kernel type.
+                    </para></listitem>
+                <listitem><para>"tiny":
+                    Defines a bare minimum configuration meant to serve as a
+                    base for very small Linux kernels.
+                    The "tiny" kernel type is independent from the "standard"
+                    configuration.
+                    Although the "tiny" kernel type does not currently include
+                    any source changes, it might in the future.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            For any given kernel type, the Metadata is defined by the
+            <filename>.scc</filename> (e.g. <filename>standard.scc</filename>).
+            Here is a partial listing for the <filename>standard.scc</filename>
+            file, which is found in the <filename>ktypes/standard</filename>
+            directory of the <filename>yocto-kernel-cache</filename> Git
+            repository:
+            <literallayout class='monospaced'>
+     # Include this kernel type fragment to get the standard features and
+     # configuration values.
+
+     # Note: if only the features are desired, but not the configuration
+     #       then this should be included as:
+     #             include ktypes/standard/standard.scc nocfg
+     #       if no chained configuration is desired, include it as:
+     #             include ktypes/standard/standard.scc nocfg inherit
+
+
+
+     include ktypes/base/base.scc
+     branch standard
+
+     kconf non-hardware standard.cfg
+
+     include features/kgdb/kgdb.scc
+                .
+                .
+                .
+
+     include cfg/net/ip6_nf.scc
+     include cfg/net/bridge.scc
+
+     include cfg/systemd.scc
+
+     include features/rfkill/rfkill.scc
+            </literallayout>
+        </para>
+
+        <para>
+            As with any <filename>.scc</filename> file, a
+            kernel type definition can aggregate other
+            <filename>.scc</filename> files with
+            <filename>include</filename> commands.
+            These definitions can also directly pull in
+            configuration fragments and patches with the
+            <filename>kconf</filename> and <filename>patch</filename>
+            commands, respectively.
+        </para>
+
+        <note>
+            It is not strictly necessary to create a kernel type
+            <filename>.scc</filename> file.
+            The Board Support Package (BSP) file can implicitly define
+            the kernel type using a <filename>define
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-KTYPE'>KTYPE</ulink> myktype</filename>
+            line.
+            See the "<link linkend='bsp-descriptions'>BSP Descriptions</link>"
+            section for more information.
+        </note>
+    </section>
+
+    <section id='bsp-descriptions'>
+        <title>BSP Descriptions</title>
+
+        <para>
+            BSP descriptions (i.e. <filename>*.scc</filename> files)
+            combine kernel types with hardware-specific features.
+            The hardware-specific Metadata is typically defined
+            independently in the BSP layer, and then aggregated with each
+            supported kernel type.
+            <note>
+                For BSPs supported by the Yocto Project, the BSP description
+                files are located in the <filename>bsp</filename> directory
+                of the
+                <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/yocto-kernel-cache/tree/bsp'><filename>yocto-kernel-cache</filename></ulink>
+                repository organized under the "Yocto Linux Kernel" heading
+                in the
+                <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi'>Yocto Project Source Repositories</ulink>.
+            </note>
+        </para>
+
+        <para>
+            This section overviews the BSP description structure, the
+            aggregation concepts, and presents a detailed example using
+            a BSP supported by the Yocto Project (i.e. BeagleBone Board).
+            For complete information on BSP layer file hierarchy, see the
+            <ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support Package (BSP) Developer's Guide</ulink>.
+        </para>
+
+        <section id='bsp-description-file-overview'>
+            <title>Overview</title>
+
+            <para>
+                For simplicity, consider the following root BSP layer
+                description files for the BeagleBone board.
+                These files employ both a structure and naming convention
+                for consistency.
+                The naming convention for the file is as follows:
+                <literallayout class='monospaced'>
+     <replaceable>bsp_root_name</replaceable>-<replaceable>kernel_type</replaceable>.scc
+                </literallayout>
+                Here are some example root layer BSP filenames for the
+                BeagleBone Board BSP, which is supported by the Yocto Project:
+                <literallayout class='monospaced'>
+     beaglebone-standard.scc
+     beaglebone-preempt-rt.scc
+                </literallayout>
+                Each file uses the root name (i.e "beaglebone") BSP name
+                followed by the kernel type.
+            </para>
+
+            <para>
+                Examine the <filename>beaglebone-standard.scc</filename>
+                file:
+                <literallayout class='monospaced'>
+     define KMACHINE beaglebone
+     define KTYPE standard
+     define KARCH arm
+
+     include ktypes/standard/standard.scc
+     branch beaglebone
+
+     include beaglebone.scc
+
+     # default policy for standard kernels
+     include features/latencytop/latencytop.scc
+     include features/profiling/profiling.scc
+                </literallayout>
+                Every top-level BSP description file should define the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>,
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KTYPE'><filename>KTYPE</filename></ulink>,
+                and <ulink url='&YOCTO_DOCS_REF_URL;#var-KARCH'><filename>KARCH</filename></ulink>
+                variables.
+                These variables allow the OpenEmbedded build system to identify
+                the description as meeting the criteria set by the recipe being
+                built.
+                This example supports the "beaglebone" machine for the
+                "standard" kernel and the "arm" architecture.
+            </para>
+
+            <para>
+                Be aware that a hard link between the
+                <filename>KTYPE</filename> variable and a kernel type
+                description file does not exist.
+                Thus, if you do not have the kernel type defined in your kernel
+                Metadata as it is here, you only need to ensure that the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-LINUX_KERNEL_TYPE'><filename>LINUX_KERNEL_TYPE</filename></ulink>
+                variable in the kernel recipe and the
+                <filename>KTYPE</filename> variable in the BSP description
+                file match.
+            </para>
+
+            <para>
+                To separate your kernel policy from your hardware configuration,
+                you include a kernel type (<filename>ktype</filename>), such as
+                "standard".
+                In the previous example, this is done using the following:
+                <literallayout class='monospaced'>
+     include ktypes/standard/standard.scc
+                </literallayout>
+                This file aggregates all the configuration fragments, patches,
+                and features that make up your standard kernel policy.
+                See the "<link linkend='kernel-types'>Kernel Types</link>"
+                section for more information.
+            </para>
+
+            <para>
+                To aggregate common configurations and features specific to the
+                kernel for <replaceable>mybsp</replaceable>, use the following:
+                <literallayout class='monospaced'>
+     include <replaceable>mybsp</replaceable>.scc
+                </literallayout>
+                You can see that in the BeagleBone example with the following:
+                <literallayout class='monospaced'>
+     include beaglebone.scc
+                </literallayout>
+                For information on how to break a complete
+                <filename>.config</filename> file into the various
+                configuration fragments, see the
+                "<link linkend='creating-config-fragments'>Creating Configuration Fragments</link>"
+                section.
+            </para>
+
+            <para>
+                Finally, if you have any configurations specific to the
+                hardware that are not in a <filename>*.scc</filename> file,
+                you can include them as follows:
+                <literallayout class='monospaced'>
+     kconf hardware <replaceable>mybsp</replaceable>-<replaceable>extra</replaceable>.cfg
+                </literallayout>
+                The BeagleBone example does not include these types of
+                configurations.
+                However, the Malta 32-bit board does ("mti-malta32").
+                Here is the <filename>mti-malta32-le-standard.scc</filename>
+                file:
+                <literallayout class='monospaced'>
+     define KMACHINE mti-malta32-le
+     define KMACHINE qemumipsel
+     define KTYPE standard
+     define KARCH mips
+
+     include ktypes/standard/standard.scc
+     branch mti-malta32
+
+     include mti-malta32.scc
+     kconf hardware mti-malta32-le.cfg
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='bsp-description-file-example-minnow'>
+            <title>Example</title>
+
+            <para>
+                Many real-world examples are more complex.
+                Like any other <filename>.scc</filename> file, BSP
+                descriptions can aggregate features.
+                Consider the Minnow BSP definition given the
+                <filename>linux-yocto-4.4</filename> branch of the
+                <filename>yocto-kernel-cache</filename> (i.e.
+                <filename>yocto-kernel-cache/bsp/minnow/minnow.scc</filename>):
+                <note>
+                    Although the Minnow Board BSP is unused, the Metadata
+                    remains and is being used here just as an example.
+                </note>
+                <literallayout class='monospaced'>
+         include cfg/x86.scc
+         include features/eg20t/eg20t.scc
+         include cfg/dmaengine.scc
+         include features/power/intel.scc
+         include cfg/efi.scc
+         include features/usb/ehci-hcd.scc
+         include features/usb/ohci-hcd.scc
+         include features/usb/usb-gadgets.scc
+         include features/usb/touchscreen-composite.scc
+         include cfg/timer/hpet.scc
+         include features/leds/leds.scc
+         include features/spi/spidev.scc
+         include features/i2c/i2cdev.scc
+         include features/mei/mei-txe.scc
+
+         # Earlyprintk and port debug requires 8250
+         kconf hardware cfg/8250.cfg
+
+         kconf hardware minnow.cfg
+         kconf hardware minnow-dev.cfg
+                </literallayout>
+            </para>
+
+            <para>
+                The <filename>minnow.scc</filename> description file includes
+                a hardware configuration fragment
+                (<filename>minnow.cfg</filename>) specific to the Minnow
+                BSP as well as several more general configuration
+                fragments and features enabling hardware found on the
+                machine.
+                This <filename>minnow.scc</filename> description file is then
+                included in each of the three
+                "minnow" description files for the supported kernel types
+                (i.e. "standard", "preempt-rt", and "tiny").
+                Consider the "minnow" description for the "standard" kernel
+                type (i.e. <filename>minnow-standard.scc</filename>:
+                <literallayout class='monospaced'>
+         define KMACHINE minnow
+         define KTYPE standard
+         define KARCH i386
+
+         include ktypes/standard
+
+         include minnow.scc
+
+         # Extra minnow configs above the minimal defined in minnow.scc
+         include cfg/efi-ext.scc
+         include features/media/media-all.scc
+         include features/sound/snd_hda_intel.scc
+
+         # The following should really be in standard.scc
+         # USB live-image support
+         include cfg/usb-mass-storage.scc
+         include cfg/boot-live.scc
+
+         # Basic profiling
+         include features/latencytop/latencytop.scc
+         include features/profiling/profiling.scc
+
+         # Requested drivers that don't have an existing scc
+         kconf hardware minnow-drivers-extra.cfg
+                </literallayout>
+                The <filename>include</filename> command midway through the file
+                includes the <filename>minnow.scc</filename> description that
+                defines all enabled hardware for the BSP that is common to
+                all kernel types.
+                Using this command significantly reduces duplication.
+            </para>
+
+            <para>
+                Now consider the "minnow" description for the "tiny" kernel
+                type (i.e. <filename>minnow-tiny.scc</filename>):
+                <literallayout class='monospaced'>
+        define KMACHINE minnow
+        define KTYPE tiny
+        define KARCH i386
+
+        include ktypes/tiny
+
+        include minnow.scc
+                </literallayout>
+                As you might expect, the "tiny" description includes quite a
+                bit less.
+                In fact, it includes only the minimal policy defined by the
+                "tiny" kernel type and the hardware-specific configuration
+                required for booting the machine along with the most basic
+                functionality of the system as defined in the base "minnow"
+                description file.
+            </para>
+
+            <para>
+                Notice again the three critical variables:
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>,
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KTYPE'><filename>KTYPE</filename></ulink>,
+                and
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KARCH'><filename>KARCH</filename></ulink>.
+                Of these variables, only <filename>KTYPE</filename>
+                has changed to specify the "tiny" kernel type.
+            </para>
+        </section>
+    </section>
+</section>
+
+<section id='kernel-metadata-location'>
+    <title>Kernel Metadata Location</title>
+
+    <para>
+        Kernel Metadata always exists outside of the kernel tree either
+        defined in a kernel recipe (recipe-space) or outside of the recipe.
+        Where you choose to define the Metadata depends on what you want
+        to do and how you intend to work.
+        Regardless of where you define the kernel Metadata, the syntax used
+        applies equally.
+    </para>
+
+    <para>
+        If you are unfamiliar with the Linux kernel and only wish
+        to apply a configuration and possibly a couple of patches provided to
+        you by others, the recipe-space method is recommended.
+        This method is also a good approach if you are working with Linux kernel
+        sources you do not control or if you just do not want to maintain a
+        Linux kernel Git repository on your own.
+        For partial information on how you can define kernel Metadata in
+        the recipe-space, see the
+        "<link linkend='modifying-an-existing-recipe'>Modifying an Existing Recipe</link>"
+        section.
+    </para>
+
+    <para>
+        Conversely, if you are actively developing a kernel and are already
+        maintaining a Linux kernel Git repository of your own, you might find
+        it more convenient to work with kernel Metadata kept outside the
+        recipe-space.
+        Working with Metadata in this area can make iterative development of
+        the Linux kernel more efficient outside of the BitBake environment.
+    </para>
+
+    <section id='recipe-space-metadata'>
+        <title>Recipe-Space Metadata</title>
+
+        <para>
+            When stored in recipe-space, the kernel Metadata files reside in a
+            directory hierarchy below
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>.
+            For a linux-yocto recipe or for a Linux kernel recipe derived
+            by copying and modifying
+            <filename>oe-core/meta-skeleton/recipes-kernel/linux/linux-yocto-custom.bb</filename>
+            to a recipe in your layer, <filename>FILESEXTRAPATHS</filename>
+            is typically set to
+            <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-THISDIR'><filename>THISDIR</filename></ulink><filename>}/${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>.
+            See the "<link linkend='modifying-an-existing-recipe'>Modifying an Existing Recipe</link>"
+            section for more information.
+        </para>
+
+        <para>
+            Here is an example that shows a trivial tree of kernel Metadata
+            stored in recipe-space within a BSP layer:
+            <literallayout class='monospaced'>
+     meta-<replaceable>my_bsp_layer</replaceable>/
+     `-- recipes-kernel
+         `-- linux
+             `-- linux-yocto
+                 |-- bsp-standard.scc
+                 |-- bsp.cfg
+                 `-- standard.cfg
+            </literallayout>
+        </para>
+
+        <para>
+            When the Metadata is stored in recipe-space, you must take
+            steps to ensure BitBake has the necessary information to decide
+            what files to fetch and when they need to be fetched again.
+            It is only necessary to specify the <filename>.scc</filename>
+            files on the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>.
+            BitBake parses them and fetches any files referenced in the
+            <filename>.scc</filename> files by the <filename>include</filename>,
+            <filename>patch</filename>, or <filename>kconf</filename> commands.
+            Because of this, it is necessary to bump the recipe
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
+            value when changing the content of files not explicitly listed
+            in the <filename>SRC_URI</filename>.
+        </para>
+
+        <para>
+            If the BSP description is in recipe space, you cannot simply list
+            the <filename>*.scc</filename> in the <filename>SRC_URI</filename>
+            statement.
+            You need to use the following form from your kernel append file:
+            <literallayout class='monospaced'>
+     SRC_URI_append_<replaceable>myplatform</replaceable> = " \
+        file://<replaceable>myplatform</replaceable>;type=kmeta;destsuffix=<replaceable>myplatform</replaceable> \
+        "
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='metadata-outside-the-recipe-space'>
+        <title>Metadata Outside the Recipe-Space</title>
+
+        <para>
+            When stored outside of the recipe-space, the kernel Metadata
+            files reside in a separate repository.
+            The OpenEmbedded build system adds the Metadata to the build as
+            a "type=kmeta" repository through the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+            variable.
+            As an example, consider the following <filename>SRC_URI</filename>
+            statement from the <filename>linux-yocto_4.12.bb</filename>
+            kernel recipe:
+            <literallayout class='monospaced'>
+     SRC_URI = "git://git.yoctoproject.org/linux-yocto-4.12.git;name=machine;branch=${KBRANCH}; \
+                git://git.yoctoproject.org/yocto-kernel-cache;type=kmeta;name=meta;branch=yocto-4.12;destsuffix=${KMETA}"
+            </literallayout>
+            <filename>${KMETA}</filename>, in this context, is simply used to
+            name the directory into which the Git fetcher places the Metadata.
+            This behavior is no different than any multi-repository
+            <filename>SRC_URI</filename> statement used in a recipe (e.g.
+            see the previous section).
+        </para>
+
+        <para>
+            You can keep kernel Metadata in a "kernel-cache", which is a
+            directory containing configuration fragments.
+            As with any Metadata kept outside the recipe-space, you simply
+            need to use the <filename>SRC_URI</filename> statement with the
+            "type=kmeta" attribute.
+            Doing so makes the kernel Metadata available during the
+            configuration phase.
+        </para>
+
+        <para>
+            If you modify the Metadata, you must not forget to update the
+            <filename>SRCREV</filename> statements in the kernel's recipe.
+            In particular, you need to update the
+            <filename>SRCREV_meta</filename> variable to match the commit in
+            the <filename>KMETA</filename> branch you wish to use.
+            Changing the data in these branches and not updating the
+            <filename>SRCREV</filename> statements to match will cause the
+            build to fetch an older commit.
+        </para>
+    </section>
+</section>
+
+<section id='organizing-your-source'>
+    <title>Organizing Your Source</title>
+
+    <para>
+        Many recipes based on the <filename>linux-yocto-custom.bb</filename>
+        recipe use Linux kernel sources that have only a single
+        branch - "master".
+        This type of repository structure is fine for linear development
+        supporting a single machine and architecture.
+        However, if you work with multiple boards and architectures,
+        a kernel source repository with multiple branches is more
+        efficient.
+        For example, suppose you need a series of patches for one board to boot.
+        Sometimes, these patches are works-in-progress or fundamentally wrong,
+        yet they are still necessary for specific boards.
+        In these situations, you most likely do not want to include these
+        patches in every kernel you build (i.e. have the patches as part of
+        the lone "master" branch).
+        It is situations like these that give rise to multiple branches used
+        within a Linux kernel sources Git repository.
+    </para>
+
+    <para>
+        Repository organization strategies exist that maximize source reuse,
+        remove redundancy, and logically order your changes.
+        This section presents strategies for the following cases:
+        <itemizedlist>
+            <listitem><para>Encapsulating patches in a feature description
+                and only including the patches in the BSP descriptions of
+                the applicable boards.</para></listitem>
+            <listitem><para>Creating a machine branch in your
+                kernel source repository and applying the patches on that
+                branch only.</para></listitem>
+            <listitem><para>Creating a feature branch in your
+                kernel source repository and merging that branch into your
+                BSP when needed.</para></listitem>
+        </itemizedlist>
+    </para>
+
+    <para>
+        The approach you take is entirely up to you
+        and depends on what works best for your development model.
+    </para>
+
+    <section id='encapsulating-patches'>
+        <title>Encapsulating Patches</title>
+
+        <para>
+            if you are reusing patches from an external tree and are not
+            working on the patches, you might find the encapsulated feature
+            to be appropriate.
+            Given this scenario, you do not need to create any branches in the
+            source repository.
+            Rather, you just take the static patches you need and encapsulate
+            them within a feature description.
+            Once you have the feature description, you simply include that into
+            the BSP description as described in the
+            "<link linkend='bsp-descriptions'>BSP Descriptions</link>"
+            section.
+        </para>
+
+        <para>
+            You can find information on how to create patches and BSP
+            descriptions in the "<link linkend='patches'>Patches</link>" and
+            "<link linkend='bsp-descriptions'>BSP Descriptions</link>"
+            sections.
+        </para>
+    </section>
+
+    <section id='machine-branches'>
+        <title>Machine Branches</title>
+
+        <para>
+            When you have multiple machines and architectures to support,
+            or you are actively working on board support, it is more
+            efficient to create branches in the repository based on
+            individual machines.
+            Having machine branches allows common source to remain in the
+            "master" branch with any features specific to a machine stored
+            in the appropriate machine branch.
+            This organization method frees you from continually reintegrating
+            your patches into a feature.
+        </para>
+
+        <para>
+            Once you have a new branch, you can set up your kernel Metadata
+            to use the branch a couple different ways.
+            In the recipe, you can specify the new branch as the
+            <filename>KBRANCH</filename> to use for the board as
+            follows:
+            <literallayout class='monospaced'>
+     KBRANCH = "mynewbranch"
+            </literallayout>
+            Another method is to use the <filename>branch</filename> command
+            in the BSP description:
+            <literallayout class='monospaced'>
+     mybsp.scc:
+        define KMACHINE mybsp
+        define KTYPE standard
+        define KARCH i386
+        include standard.scc
+
+        branch mynewbranch
+
+        include mybsp-hw.scc
+            </literallayout>
+        </para>
+
+        <para>
+            If you find yourself with numerous branches, you might consider
+            using a hierarchical branching system similar to what the
+            Yocto Linux Kernel Git repositories use:
+            <literallayout class='monospaced'>
+     <replaceable>common</replaceable>/<replaceable>kernel_type</replaceable>/<replaceable>machine</replaceable>
+            </literallayout>
+        </para>
+
+        <para>
+            If you had two kernel types, "standard" and "small" for
+            instance, three machines, and <replaceable>common</replaceable>
+            as <filename>mydir</filename>, the branches in your
+            Git repository might look like this:
+            <literallayout class='monospaced'>
+     mydir/base
+     mydir/standard/base
+     mydir/standard/machine_a
+     mydir/standard/machine_b
+     mydir/standard/machine_c
+     mydir/small/base
+     mydir/small/machine_a
+            </literallayout>
+        </para>
+
+        <para>
+            This organization can help clarify the branch relationships.
+            In this case, <filename>mydir/standard/machine_a</filename>
+            includes everything in <filename>mydir/base</filename> and
+            <filename>mydir/standard/base</filename>.
+            The "standard" and "small" branches add sources specific to those
+            kernel types that for whatever reason are not appropriate for the
+            other branches.
+            <note>
+                The "base" branches are an artifact of the way Git manages
+                its data internally on the filesystem: Git will not allow you
+                to use <filename>mydir/standard</filename> and
+                <filename>mydir/standard/machine_a</filename> because it
+                would have to create a file and a directory named "standard".
+            </note>
+        </para>
+    </section>
+
+    <section id='feature-branches'>
+        <title>Feature Branches</title>
+
+        <para>
+            When you are actively developing new features, it can be more
+            efficient to work with that feature as a branch, rather than
+            as a set of patches that have to be regularly updated.
+            The Yocto Project Linux kernel tools provide for this with
+            the <filename>git merge</filename> command.
+        </para>
+
+        <para>
+            To merge a feature branch into a BSP, insert the
+            <filename>git merge</filename> command after any
+            <filename>branch</filename> commands:
+            <literallayout class='monospaced'>
+     mybsp.scc:
+        define KMACHINE mybsp
+        define KTYPE standard
+        define KARCH i386
+        include standard.scc
+
+        branch mynewbranch
+        git merge myfeature
+
+        include mybsp-hw.scc
+            </literallayout>
+        </para>
+    </section>
+</section>
+
+<section id='scc-reference'>
+    <title>SCC Description File Reference</title>
+
+    <para>
+        This section provides a brief reference for the commands you can use
+        within an SCC description file (<filename>.scc</filename>):
+        <itemizedlist>
+            <listitem><para>
+                <filename>branch [ref]</filename>:
+                Creates a new branch relative to the current branch
+                (typically <filename>${KTYPE}</filename>) using
+                the currently checked-out branch, or "ref" if specified.
+                </para></listitem>
+            <listitem><para>
+                <filename>define</filename>:
+                Defines variables, such as
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>,
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KTYPE'><filename>KTYPE</filename></ulink>,
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KARCH'><filename>KARCH</filename></ulink>,
+                and
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KFEATURE_DESCRIPTION'><filename>KFEATURE_DESCRIPTION</filename></ulink>.
+                </para></listitem>
+            <listitem><para>
+                <filename>include SCC_FILE</filename>:
+                Includes an SCC file in the current file.
+                The file is parsed as if you had inserted it inline.
+                </para></listitem>
+            <listitem><para>
+                <filename>kconf [hardware|non-hardware] CFG_FILE</filename>:
+                Queues a configuration fragment for merging into the final
+                Linux <filename>.config</filename> file.</para></listitem>
+            <listitem><para>
+                <filename>git merge GIT_BRANCH</filename>:
+                Merges the feature branch into the current branch.
+                </para></listitem>
+            <listitem><para>
+                <filename>patch PATCH_FILE</filename>:
+                Applies the patch to the current Git branch.
+                </para></listitem>
+        </itemizedlist>
+    </para>
+</section>
+
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-common.rst b/poky/documentation/kernel-dev/kernel-dev-common.rst
index 64235f3..d4b60a9 100644
--- a/poky/documentation/kernel-dev/kernel-dev-common.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-common.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 ************
 Common Tasks
diff --git a/poky/documentation/kernel-dev/kernel-dev-common.xml b/poky/documentation/kernel-dev/kernel-dev-common.xml
new file mode 100644
index 0000000..8e8a6db
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-common.xml
@@ -0,0 +1,2730 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='kernel-dev-common'>
+<title>Common Tasks</title>
+
+    <para>
+        This chapter presents several common tasks you perform when you
+        work with the Yocto Project Linux kernel.
+        These tasks include preparing your host development system for
+        kernel development, preparing a layer, modifying an existing recipe,
+        patching the kernel, configuring the kernel, iterative development,
+        working with your own sources, and incorporating out-of-tree modules.
+        <note>
+            The examples presented in this chapter work with the Yocto Project
+            2.4 Release and forward.
+        </note>
+    </para>
+
+    <section id='preparing-the-build-host-to-work-on-the-kernel'>
+        <title>Preparing the Build Host to Work on the Kernel</title>
+
+        <para>
+            Before you can do any kernel development, you need to be
+            sure your build host is set up to use the Yocto Project.
+            For information on how to get set up, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#dev-preparing-the-build-host'>Preparing the Build Host</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+            Part of preparing the system is creating a local Git
+            repository of the
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+            (<filename>poky</filename>) on your system.
+            Follow the steps in the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#cloning-the-poky-repository'>Cloning the <filename>poky</filename> Repository</ulink>"
+            section in the Yocto Project Development Tasks Manual to set up your
+            Source Directory.
+            <note>
+                Be sure you check out the appropriate development branch or
+                you create your local branch by checking out a specific tag
+                to get the desired version of Yocto Project.
+                See the
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#checking-out-by-branch-in-poky'>Checking Out by Branch in Poky</ulink>"
+                and
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#checkout-out-by-tag-in-poky'>Checking Out by Tag in Poky</ulink>"
+                sections in the Yocto Project Development Tasks Manual for more
+                information.
+            </note>
+        </para>
+
+        <para>
+            Kernel development is best accomplished using
+            <ulink url='&YOCTO_DOCS_SDK_URL;#using-devtool-in-your-sdk-workflow'><filename>devtool</filename></ulink>
+            and not through traditional kernel workflow methods.
+            The remainder of this section provides information for both
+            scenarios.
+        </para>
+
+        <section id='getting-ready-to-develop-using-devtool'>
+            <title>Getting Ready to Develop Using <filename>devtool</filename></title>
+
+            <para>
+                Follow these steps to prepare to update the kernel image using
+                <filename>devtool</filename>.
+                Completing this procedure leaves you with a clean kernel image
+                and ready to make modifications as described in the
+                "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+                section:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Initialize the BitBake Environment:</emphasis>
+                        Before building an extensible SDK, you need to
+                        initialize the BitBake build environment by sourcing the
+                        build environment script
+                        (i.e. <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>):
+                        <literallayout class='monospaced'>
+     $ cd ~/poky
+     $ source oe-init-build-env
+                        </literallayout>
+                        <note>
+                            The previous commands assume the
+                            <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+                            (i.e. <filename>poky</filename>) have been cloned
+                            using Git and the local repository is named
+                            "poky".
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Prepare Your <filename>local.conf</filename> File:</emphasis>
+                        By default, the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        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
+                        <filename>MACHINE</filename> variable appropriately in
+                        your <filename>conf/local.conf</filename> file found in
+                        the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                        (i.e. <filename>~/poky/build</filename> in this
+                        example).</para>
+
+                        <para>Also, since you are preparing to work on the
+                        kernel image, you need to set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</filename></ulink>
+                        variable to include kernel modules.</para>
+
+                        <para>In this example we wish to build for qemux86 so
+                        we must set the <filename>MACHINE</filename> variable
+                        to "qemux86" and also add the "kernel-modules". As described
+                        we do this by appending to <filename>conf/local.conf</filename>:
+                        <literallayout class='monospaced'>
+     MACHINE = "qemux86"
+     MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Layer for Patches:</emphasis>
+                        You need to create a layer to hold patches created
+                        for the kernel image.
+                        You can use the
+                        <filename>bitbake-layers create-layer</filename>
+                        command as follows:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake-layers create-layer ../../meta-mylayer
+     NOTE: Starting bitbake server...
+     Add your new layer with 'bitbake-layers add-layer ../../meta-mylayer'
+     $
+                        </literallayout>
+                        <note>
+                            For background information on working with
+                            common and BSP layers, see the
+                            "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>"
+                            section in the Yocto Project Development Tasks
+                            Manual and the
+                            "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>"
+                            section in the Yocto Project Board Support (BSP)
+                            Developer's Guide, respectively.
+                            For information on how to use the
+                            <filename>bitbake-layers create-layer</filename>
+                            command to quickly set up a layer, see the
+                            "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-a-general-layer-using-the-bitbake-layers-script'>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</ulink>"
+                            section in the Yocto Project Development Tasks
+                            Manual.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Inform the BitBake Build Environment About
+                        Your Layer:</emphasis>
+                        As directed when you created your layer, you need to
+                        add the layer to the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'><filename>BBLAYERS</filename></ulink>
+                        variable in the <filename>bblayers.conf</filename> file
+                        as follows:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake-layers add-layer ../../meta-mylayer
+     NOTE: Starting bitbake server...
+     $
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the Extensible SDK:</emphasis>
+                        Use BitBake to build the extensible SDK specifically
+                        for use with images to be run using QEMU:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake core-image-minimal -c populate_sdk_ext
+                        </literallayout>
+                        Once the build finishes, you can find the SDK installer
+                        file (i.e. <filename>*.sh</filename> file) in the
+                        following directory:
+                        <literallayout class='monospaced'>
+     ~/poky/build/tmp/deploy/sdk
+                        </literallayout>
+                        For this example, the installer file is named
+                        <filename>poky-glibc-x86_64-core-image-minimal-i586-toolchain-ext-&DISTRO;.sh</filename>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Install the Extensible SDK:</emphasis>
+                        Use the following command to install the SDK.
+                        For this example, install the SDK in the default
+                        <filename>~/poky_sdk</filename> directory:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build/tmp/deploy/sdk
+     $ ./poky-glibc-x86_64-core-image-minimal-i586-toolchain-ext-&DISTRO;.sh
+     Poky (Yocto Project Reference Distro) Extensible SDK installer version &DISTRO;
+     ============================================================================
+     Enter target directory for SDK (default: ~/poky_sdk):
+     You are about to install the SDK to "/home/scottrif/poky_sdk". Proceed [Y/n]? Y
+     Extracting SDK......................................done
+     Setting it up...
+     Extracting buildtools...
+     Preparing build system...
+     Parsing recipes: 100% |#################################################################| Time: 0:00:52
+     Initializing tasks: 100% |############## ###############################################| Time: 0:00:04
+     Checking sstate mirror object availability: 100% |######################################| Time: 0:00:00
+     Parsing recipes: 100% |#################################################################| Time: 0:00:33
+     Initializing tasks: 100% |##############################################################| Time: 0:00:00
+     done
+     SDK has been successfully set up and is ready to be used.
+     Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g.
+      $ . /home/scottrif/poky_sdk/environment-setup-i586-poky-linux
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para id='setting-up-the-esdk-terminal'>
+                        <emphasis>Set Up a New Terminal to Work With the
+                        Extensible SDK:</emphasis>
+                        You must set up a new terminal to work with the SDK.
+                        You cannot use the same BitBake shell used to build the
+                        installer.</para>
+
+                        <para>After opening a new shell, run the SDK environment
+                        setup script as directed by the output from installing
+                        the SDK:
+                        <literallayout class='monospaced'>
+     $ source ~/poky_sdk/environment-setup-i586-poky-linux
+     "SDK environment now set up; additionally you may now run devtool to perform development tasks.
+     Run devtool --help for further details.
+                        </literallayout>
+                        <note>
+                            If you get a warning about attempting to use the
+                            extensible SDK in an environment set up to run
+                            BitBake, you did not use a new shell.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Build the Clean Image:</emphasis>
+                        The final step in preparing to work on the kernel is to
+                        build an initial image using
+                        <filename>devtool</filename> in the new terminal you
+                        just set up and initialized for SDK work:
+                        <literallayout class='monospaced'>
+     $ devtool build-image
+     Parsing recipes: 100% |##########################################| Time: 0:00:05
+     Parsing of 830 .bb files complete (0 cached, 830 parsed). 1299 targets, 47 skipped, 0 masked, 0 errors.
+     WARNING: No packages to add, building image core-image-minimal unmodified
+     Loading cache: 100% |############################################| Time: 0:00:00
+     Loaded 1299 entries from dependency cache.
+     NOTE: Resolving any missing task queue dependencies
+     Initializing tasks: 100% |#######################################| Time: 0:00:07
+     Checking sstate mirror object availability: 100% |###############| Time: 0:00:00
+     NOTE: Executing SetScene Tasks
+     NOTE: Executing RunQueue Tasks
+     NOTE: Tasks Summary: Attempted 2866 tasks of which 2604 didn't need to be rerun and all succeeded.
+     NOTE: Successfully built core-image-minimal. You can find output files in /home/scottrif/poky_sdk/tmp/deploy/images/qemux86
+                        </literallayout>
+                        If you were building for actual hardware and not for
+                        emulation, you could flash the image to a USB stick
+                        on <filename>/dev/sdd</filename> and boot your device.
+                        For an example that uses a Minnowboard, see the
+                        <ulink url='https://wiki.yoctoproject.org/wiki/TipsAndTricks/KernelDevelopmentWithEsdk'>TipsAndTricks/KernelDevelopmentWithEsdk</ulink>
+                        Wiki page.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                At this point you have set up to start making modifications to
+                the kernel by using the extensible SDK.
+                For a continued example, see the
+                "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+                section.
+            </para>
+        </section>
+
+        <section id='getting-ready-for-traditional-kernel-development'>
+            <title>Getting Ready for Traditional Kernel Development</title>
+
+            <para>
+                Getting ready for traditional kernel development using the Yocto
+                Project involves many of the same steps as described in the
+                previous section.
+                However, you need to establish a local copy of the kernel source
+                since you will be editing these files.
+            </para>
+
+            <para>
+                Follow these steps to prepare to update the kernel image using
+                traditional kernel development flow with the Yocto Project.
+                Completing this procedure leaves you ready to make modifications
+                to the kernel source as described in the
+                "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+                section:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Initialize the BitBake Environment:</emphasis>
+                        Before you can do anything using BitBake, you need to
+                        initialize the BitBake build environment by sourcing the
+                        build environment script
+                        (i.e. <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>).
+                        Also, for this example, be sure that the local branch
+                        you have checked out for <filename>poky</filename> is
+                        the Yocto Project &DISTRO_NAME; branch.
+                        If you need to checkout out the &DISTRO_NAME; branch,
+                        see the
+                        "<ulink url='&YOCTO_DOCS_DEV_URL;#checking-out-by-branch-in-poky'>Checking out by Branch in Poky</ulink>"
+                        section in the Yocto Project Development Tasks Manual.
+                        <literallayout class='monospaced'>
+     $ cd ~/poky
+     $ git branch
+     master
+     * &DISTRO_NAME;
+     $ source oe-init-build-env
+                        </literallayout>
+                        <note>
+                            The previous commands assume the
+                            <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+                            (i.e. <filename>poky</filename>) have been cloned
+                            using Git and the local repository is named
+                            "poky".
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Prepare Your <filename>local.conf</filename>
+                        File:</emphasis>
+                        By default, the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
+                        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
+                        <filename>MACHINE</filename> variable appropriately in
+                        your <filename>conf/local.conf</filename> file found
+                        in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                        (i.e. <filename>~/poky/build</filename> in this
+                        example).</para>
+
+                        <para>Also, since you are preparing to work on the
+                        kernel image, you need to set the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</filename></ulink>
+                        variable to include kernel modules.</para>
+
+                        <para>In this example we wish to build for qemux86 so
+                        we must set the <filename>MACHINE</filename> variable
+                        to "qemux86" and also add the "kernel-modules". As described
+                        we do this by appending to <filename>conf/local.conf</filename>:
+                        <literallayout class='monospaced'>
+     MACHINE = "qemux86"
+     MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules"
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Layer for Patches:</emphasis>
+                        You need to create a layer to hold patches created
+                        for the kernel image.
+                        You can use the
+                        <filename>bitbake-layers create-layer</filename>
+                        command as follows:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake-layers create-layer ../../meta-mylayer
+     NOTE: Starting bitbake server...
+     Add your new layer with 'bitbake-layers add-layer ../../meta-mylayer'
+                        </literallayout>
+                        <note>
+                            For background information on working with
+                            common and BSP layers, see the
+                            "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>"
+                            section in the Yocto Project Development Tasks
+                            Manual and the
+                            "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-layers'>BSP Layers</ulink>"
+                            section in the Yocto Project Board Support (BSP)
+                            Developer's Guide, respectively.
+                            For information on how to use the
+                            <filename>bitbake-layers create-layer</filename>
+                            command to quickly set up a layer, see the
+                            "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-a-general-layer-using-the-bitbake-layers-script'>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</ulink>"
+                            section in the Yocto Project Development Tasks
+                            Manual.
+                        </note>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Inform the BitBake Build Environment About
+                        Your Layer:</emphasis>
+                        As directed when you created your layer, you need to add
+                        the layer to the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'><filename>BBLAYERS</filename></ulink>
+                        variable in the <filename>bblayers.conf</filename> file
+                        as follows:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake-layers add-layer ../../meta-mylayer
+     NOTE: Starting bitbake server ...
+     $
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Local Copy of the Kernel Git
+                        Repository:</emphasis>
+                        You can find Git repositories of supported Yocto Project
+                        kernels organized under "Yocto Linux Kernel" in the
+                        Yocto Project Source Repositories at
+                        <ulink url='&YOCTO_GIT_URL;'></ulink>.
+                        </para>
+
+                        <para>
+                        For simplicity, it is recommended that you create your
+                        copy of the kernel Git repository outside of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>,
+                        which is usually named <filename>poky</filename>.
+                        Also, be sure you are in the
+                        <filename>standard/base</filename> branch.
+                        </para>
+
+                        <para>
+                        The following commands show how to create a local copy
+                        of the <filename>linux-yocto-4.12</filename> kernel and
+                        be in the <filename>standard/base</filename> branch.
+                        <note>
+                            The <filename>linux-yocto-4.12</filename> kernel
+                            can be used with the Yocto Project 2.4 release
+                            and forward.
+                            You cannot use the
+                            <filename>linux-yocto-4.12</filename> kernel with
+                            releases prior to Yocto Project 2.4:
+                        </note>
+                        <literallayout class='monospaced'>
+     $ cd ~
+     $ git clone git://git.yoctoproject.org/linux-yocto-4.12 --branch standard/base
+     Cloning into 'linux-yocto-4.12'...
+     remote: Counting objects: 6097195, done.
+     remote: Compressing objects: 100% (901026/901026), done.
+     remote: Total 6097195 (delta 5152604), reused 6096847 (delta 5152256)
+     Receiving objects: 100% (6097195/6097195), 1.24 GiB | 7.81 MiB/s, done.
+     Resolving deltas: 100% (5152604/5152604), done.
+     Checking connectivity... done.
+     Checking out files: 100% (59846/59846), done.
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create a Local Copy of the Kernel Cache Git
+                        Repository:</emphasis>
+                        For simplicity, it is recommended that you create your
+                        copy of the kernel cache Git repository outside of the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>,
+                        which is usually named <filename>poky</filename>.
+                        Also, for this example, be sure you are in the
+                        <filename>yocto-4.12</filename> branch.
+                        </para>
+
+                        <para>
+                        The following commands show how to create a local copy
+                        of the <filename>yocto-kernel-cache</filename> and
+                        be in the <filename>yocto-4.12</filename> branch:
+                        <literallayout class='monospaced'>
+     $ cd ~
+     $ git clone git://git.yoctoproject.org/yocto-kernel-cache --branch yocto-4.12
+     Cloning into 'yocto-kernel-cache'...
+     remote: Counting objects: 22639, done.
+     remote: Compressing objects: 100% (9761/9761), done.
+     remote: Total 22639 (delta 12400), reused 22586 (delta 12347)
+     Receiving objects: 100% (22639/22639), 22.34 MiB | 6.27 MiB/s, done.
+     Resolving deltas: 100% (12400/12400), done.
+     Checking connectivity... done.
+                        </literallayout>
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                At this point, you are ready to start making modifications to
+                the kernel using traditional kernel development steps.
+                For a continued example, see the
+                "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+                section.
+            </para>
+        </section>
+    </section>
+
+    <section id='creating-and-preparing-a-layer'>
+        <title>Creating and Preparing a Layer</title>
+
+        <para>
+            If you are going to be modifying kernel recipes, it is recommended
+            that you create and prepare your own layer in which to do your
+            work.
+            Your layer contains its own
+            <ulink url='&YOCTO_DOCS_REF_URL;#bitbake-term'>BitBake</ulink>
+            append files (<filename>.bbappend</filename>) and provides a
+            convenient mechanism to create your own recipe files
+            (<filename>.bb</filename>) as well as store and use kernel
+            patch files.
+            For background information on working with layers, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+            <note><title>Tip</title>
+                The Yocto Project comes with many tools that simplify
+                tasks you need to perform.
+                One such tool is the
+                <filename>bitbake-layers create-layer</filename>
+                command, which simplifies creating a new layer.
+                See the
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-a-general-layer-using-the-bitbake-layers-script'>Creating a General Layer Using the <filename>bitbake-layers</filename> Script</ulink>"
+                section in the Yocto Project Development Tasks Manual for
+                information on how to use this script to quick set up a
+                new layer.
+            </note>
+        </para>
+
+        <para>
+            To better understand the layer you create for kernel development,
+            the following section describes how to create a layer
+            without the aid of tools.
+            These steps assume creation of a layer named
+            <filename>mylayer</filename> in your home directory:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Create Structure</emphasis>:
+                    Create the layer's structure:
+                    <literallayout class='monospaced'>
+     $ cd $HOME
+     $ mkdir meta-mylayer
+     $ mkdir meta-mylayer/conf
+     $ mkdir meta-mylayer/recipes-kernel
+     $ mkdir meta-mylayer/recipes-kernel/linux
+     $ mkdir meta-mylayer/recipes-kernel/linux/linux-yocto
+                    </literallayout>
+                    The <filename>conf</filename> directory holds your
+                    configuration files, while the
+                    <filename>recipes-kernel</filename> directory holds your
+                    append file and eventual patch files.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Create the Layer Configuration File</emphasis>:
+                    Move to the <filename>meta-mylayer/conf</filename>
+                    directory and create the <filename>layer.conf</filename>
+                    file as follows:
+                    <literallayout class='monospaced'>
+     # We have a conf and classes directory, add to BBPATH
+     BBPATH .= ":${LAYERDIR}"
+
+     # We have recipes-* directories, add to BBFILES
+     BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
+                 ${LAYERDIR}/recipes-*/*/*.bbappend"
+
+     BBFILE_COLLECTIONS += "mylayer"
+     BBFILE_PATTERN_mylayer = "^${LAYERDIR}/"
+     BBFILE_PRIORITY_mylayer = "5"
+                    </literallayout>
+                    Notice <filename>mylayer</filename> as part of the last
+                    three statements.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Create the Kernel Recipe Append File</emphasis>:
+                    Move to the
+                    <filename>meta-mylayer/recipes-kernel/linux</filename>
+                    directory and create the kernel's append file.
+                    This example uses the
+                    <filename>linux-yocto-4.12</filename> kernel.
+                    Thus, the name of the append file is
+                    <filename>linux-yocto_4.12.bbappend</filename>:
+                    <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+
+     SRC_URI_append = " file://<replaceable>patch-file-one</replaceable>"
+     SRC_URI_append = " file://<replaceable>patch-file-two</replaceable>"
+     SRC_URI_append = " file://<replaceable>patch-file-three</replaceable>"
+                    </literallayout>
+                    The
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    statements enable the OpenEmbedded build system to find
+                    patch files.
+                    For more information on using append files, see the
+                    "<ulink url='&YOCTO_DOCS_DEV_URL;#using-bbappend-files'>Using .bbappend Files in Your Layer</ulink>"
+                    section in the Yocto Project Development Tasks Manual.
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id='modifying-an-existing-recipe'>
+        <title>Modifying an Existing Recipe</title>
+
+        <para>
+            In many cases, you can customize an existing linux-yocto recipe to
+            meet the needs of your project.
+            Each release of the Yocto Project provides a few Linux
+            kernel recipes from which you can choose.
+            These are located in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+            in <filename>meta/recipes-kernel/linux</filename>.
+        </para>
+
+        <para>
+            Modifying an existing recipe can consist of the following:
+            <itemizedlist>
+                <listitem><para>Creating the append file</para></listitem>
+                <listitem><para>Applying patches</para></listitem>
+                <listitem><para>Changing the configuration</para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            Before modifying an existing recipe, be sure that you have created
+            a minimal, custom layer from which you can work.
+            See the
+            "<link linkend='creating-and-preparing-a-layer'>Creating and Preparing a Layer</link>"
+            section for information.
+        </para>
+
+        <section id='creating-the-append-file'>
+            <title>Creating the Append File</title>
+
+            <para>
+                You create this file in your custom layer.
+                You also name it accordingly based on the linux-yocto recipe
+                you are using.
+                For example, if you are modifying the
+                <filename>meta/recipes-kernel/linux/linux-yocto_4.12.bb</filename>
+                recipe, the append file will typically be located as follows
+                within your custom layer:
+                <literallayout class='monospaced'>
+     <replaceable>your-layer</replaceable>/recipes-kernel/linux/linux-yocto_4.12.bbappend
+                </literallayout>
+                The append file should initially extend the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                search path by prepending the directory that contains your
+                files to the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                variable as follows:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+                </literallayout>
+                The path <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-THISDIR'><filename>THISDIR</filename></ulink><filename>}/${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
+                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 <filename>FILESPATH</filename> as
+                described above, you must place the files in your layer in the
+                following area:
+                <literallayout class='monospaced'>
+     <replaceable>your-layer</replaceable>/recipes-kernel/linux/linux-yocto/
+                </literallayout>
+                <note>If you are working on a new machine Board Support Package
+                    (BSP), be sure to refer to the
+                    <ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support Package (BSP) Developer's Guide</ulink>.
+                </note>
+            </para>
+
+            <para>
+                As an example, consider the following append file
+                used by the BSPs in <filename>meta-yocto-bsp</filename>:
+                <literallayout class='monospaced'>
+     meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend
+                </literallayout>
+                The following listing shows the 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 <filename>meta-yocto-bsp</filename>
+                layer upstream.
+                <literallayout class='monospaced'>
+     KBRANCH_genericx86  = "standard/base"
+     KBRANCH_genericx86-64  = "standard/base"
+
+     KMACHINE_genericx86 ?= "common-pc"
+     KMACHINE_genericx86-64 ?= "common-pc-64"
+     KBRANCH_edgerouter = "standard/edgerouter"
+     KBRANCH_beaglebone = "standard/beaglebone"
+
+     SRCREV_machine_genericx86    ?= "d09f2ce584d60ecb7890550c22a80c48b83c2e19"
+     SRCREV_machine_genericx86-64 ?= "d09f2ce584d60ecb7890550c22a80c48b83c2e19"
+     SRCREV_machine_edgerouter ?= "b5c8cfda2dfe296410d51e131289fb09c69e1e7d"
+     SRCREV_machine_beaglebone ?= "b5c8cfda2dfe296410d51e131289fb09c69e1e7d"
+
+
+     COMPATIBLE_MACHINE_genericx86 = "genericx86"
+     COMPATIBLE_MACHINE_genericx86-64 = "genericx86-64"
+     COMPATIBLE_MACHINE_edgerouter = "edgerouter"
+     COMPATIBLE_MACHINE_beaglebone = "beaglebone"
+
+     LINUX_VERSION_genericx86 = "4.12.7"
+     LINUX_VERSION_genericx86-64 = "4.12.7"
+     LINUX_VERSION_edgerouter = "4.12.10"
+     LINUX_VERSION_beaglebone = "4.12.10"
+                </literallayout>
+                This append file contains statements used to support
+                several BSPs that ship with the Yocto Project.
+                The file defines machines using the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-COMPATIBLE_MACHINE'><filename>COMPATIBLE_MACHINE</filename></ulink>
+                variable and uses the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KMACHINE'><filename>KMACHINE</filename></ulink>
+                variable to ensure the machine name used by the OpenEmbedded
+                build system maps to the machine name used by the Linux Yocto
+                kernel.
+                The file also uses the optional
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KBRANCH'><filename>KBRANCH</filename></ulink>
+                variable to ensure the build process uses the
+                appropriate kernel branch.
+            </para>
+
+            <para>
+                Although this particular example does not use it, the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_FEATURES'><filename>KERNEL_FEATURES</filename></ulink>
+                variable could be used to enable features specific to
+                the kernel.
+                The append file points to specific commits in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
+                Git repository and the <filename>meta</filename> Git repository
+                branches to identify the exact kernel needed to build the
+                BSP.
+            </para>
+
+            <para>
+                One thing missing in this particular BSP, which you will
+                typically need when developing a BSP, is the kernel
+                configuration file (<filename>.config</filename>) for your BSP.
+                When developing a BSP, you probably have a kernel configuration
+                file or a set of kernel configuration files that, when taken
+                together, define the kernel configuration for your BSP.
+                You can accomplish this definition by putting the configurations
+                in a file or a set of files inside a directory located at the
+                same level as your kernel's append file and having the same
+                name as the kernel's main recipe file.
+                With all these conditions met, simply reference those files in
+                the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                statement in the append file.
+            </para>
+
+            <para>
+                For example, suppose you had some configuration options
+                in a file called <filename>network_configs.cfg</filename>.
+                You can place that file inside a directory named
+                <filename>linux-yocto</filename> and then add
+                a <filename>SRC_URI</filename> 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.
+                <literallayout class='monospaced'>
+     SRC_URI += "file://network_configs.cfg"
+                </literallayout>
+            </para>
+
+            <para>
+                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
+                <filename>SRC_URI</filename> statement like the following
+                in your append file:
+                <literallayout class='monospaced'>
+     SRC_URI += "file://myconfig.cfg \
+                 file://eth.cfg \
+                 file://gfx.cfg"
+                </literallayout>
+            </para>
+
+            <para>
+                Another variable you can use in your kernel recipe append
+                file is the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                variable.
+                When you use this statement, you are extending the locations
+                used by the OpenEmbedded system to look for files and
+                patches as the recipe is processed.
+            </para>
+
+            <note>
+                <para>
+                    Other methods exist to accomplish 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
+                    <filename>meta</filename> branch, make your changes, and
+                    then push the changes to the local bare clone of the
+                    kernel.
+                    The result is that you directly add configuration options
+                    to the <filename>meta</filename> branch for your BSP.
+                    The configuration options will likely end up in that
+                    location anyway if the BSP gets added to the Yocto Project.
+                </para>
+
+                <para>
+                    In general, however, the Yocto Project maintainers take
+                    care of moving the <filename>SRC_URI</filename>-specified
+                    configuration options to the kernel's
+                    <filename>meta</filename> branch.
+                    Not only is it easier for BSP developers to not have to
+                    worry about putting 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 common configurations into
+                    common features.
+                </para>
+            </note>
+        </section>
+
+        <section id='applying-patches'>
+            <title>Applying Patches</title>
+
+            <para>
+                If you have a single patch or a small series of patches
+                that you want to apply to the Linux kernel source, you
+                can do so just as you would with any other recipe.
+                You first copy the patches to the path added to
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                in your <filename>.bbappend</filename> file as described in
+                the previous section, and then reference them in
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                statements.
+            </para>
+
+            <para>
+                For example, you can apply a three-patch series by adding the
+                following lines to your linux-yocto
+                <filename>.bbappend</filename> file in your layer:
+                <literallayout class='monospaced'>
+     SRC_URI += "file://0001-first-change.patch"
+     SRC_URI += "file://0002-second-change.patch"
+     SRC_URI += "file://0003-third-change.patch"
+                </literallayout>
+                The next time you run BitBake to build the Linux kernel,
+                BitBake detects the change in the recipe and fetches and
+                applies the patches before building the kernel.
+            </para>
+
+            <para>
+                For a detailed example showing how to patch the kernel using
+                <filename>devtool</filename>, see the
+                "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+                and
+                "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+                sections.
+            </para>
+        </section>
+
+        <section id='changing-the-configuration'>
+            <title>Changing the Configuration</title>
+
+            <para>
+                You can make wholesale or incremental changes to the final
+                <filename>.config</filename> file used for the eventual
+                Linux kernel configuration by including a
+                <filename>defconfig</filename> file and by specifying
+                configuration fragments in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                to be applied to that file.
+            </para>
+
+            <para>
+                If you have a complete, working Linux kernel
+                <filename>.config</filename>
+                file you want to use for the configuration, as before, copy
+                that file to the appropriate <filename>${PN}</filename>
+                directory in your layer's
+                <filename>recipes-kernel/linux</filename> directory,
+                and rename the copied file to "defconfig".
+                Then, add the following lines to the linux-yocto
+                <filename>.bbappend</filename> file in your layer:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+     SRC_URI += "file://defconfig"
+                </literallayout>
+                The <filename>SRC_URI</filename> tells the build system how to
+                search for the file, while the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                extends the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                variable (search directories) to include the
+                <filename>${PN}</filename> directory you created to hold the
+                configuration changes.
+            </para>
+
+            <note>
+                The build system applies the configurations from the
+                <filename>defconfig</filename> file before applying any
+                subsequent configuration fragments.
+                The final kernel configuration is a combination of the
+                configurations in the <filename>defconfig</filename> file and
+                any configuration fragments you provide.
+                You need to realize that if you have any configuration
+                fragments, the build system applies these on top of and
+                after applying the existing <filename>defconfig</filename>
+                file configurations.
+            </note>
+
+            <para>
+                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 <filename>8250.cfg</filename> in
+                the <filename>${PN}</filename> directory with the following
+                content (without indentation):
+                <literallayout class='monospaced'>
+     CONFIG_SERIAL_8250=y
+     CONFIG_SERIAL_8250_CONSOLE=y
+     CONFIG_SERIAL_8250_PCI=y
+     CONFIG_SERIAL_8250_NR_UARTS=4
+     CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+     CONFIG_SERIAL_CORE=y
+     CONFIG_SERIAL_CORE_CONSOLE=y
+                </literallayout>
+                Next, include this configuration fragment and extend the
+                <filename>FILESPATH</filename> variable in your
+                <filename>.bbappend</filename> file:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+     SRC_URI += "file://8250.cfg"
+                </literallayout>
+                The next time you run BitBake to build the Linux kernel, BitBake
+                detects the change in the recipe and fetches and applies the
+                new configuration before building the kernel.
+            </para>
+
+            <para>
+                For a detailed example showing how to configure the kernel,
+                see the
+                "<link linkend='configuring-the-kernel'>Configuring the Kernel</link>"
+                section.
+            </para>
+        </section>
+
+        <section id='using-an-in-tree-defconfig-file'>
+            <title>Using an "In-Tree"&nbsp;&nbsp;<filename>defconfig</filename> File</title>
+
+            <para>
+                It might be desirable to have kernel configuration fragment
+                support through a <filename>defconfig</filename> file that
+                is pulled from the kernel source tree for the configured
+                machine.
+                By default, the OpenEmbedded build system looks for
+                <filename>defconfig</filename> files in the layer used for
+                Metadata, which is "out-of-tree", and then configures them
+                using the following:
+                <literallayout class='monospaced'>
+     SRC_URI += "file://defconfig"
+                </literallayout>
+                If you do not want to maintain copies of
+                <filename>defconfig</filename> files in your layer but would
+                rather allow users to use the default configuration from the
+                kernel tree and still be able to add configuration fragments
+                to the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                through, for example, append files, you can direct the
+                OpenEmbedded build system to use a
+                <filename>defconfig</filename> file that is "in-tree".
+            </para>
+
+            <para>
+                To specify an "in-tree" <filename>defconfig</filename> file,
+                use the following statement form:
+                <literallayout class='monospaced'>
+     KBUILD_DEFCONFIG_<replaceable>KMACHINE</replaceable> ?= <replaceable>defconfig_file</replaceable>
+                </literallayout>
+                Here is an example that assigns the
+                <filename>KBUILD_DEFCONFIG</filename> variable based on
+                "raspberrypi2" and provides the path to the "in-tree"
+                <filename>defconfig</filename> file
+                to be used for a Raspberry Pi 2,
+                which is based on the Broadcom 2708/2709 chipset:
+                <literallayout class='monospaced'>
+     KBUILD_DEFCONFIG_raspberrypi2 ?= "bcm2709_defconfig"
+                </literallayout>
+            </para>
+
+            <para>
+                Aside from modifying your kernel recipe and providing your own
+                <filename>defconfig</filename> file, you need to be sure no
+                files or statements set <filename>SRC_URI</filename> to use a
+                <filename>defconfig</filename> other than your "in-tree"
+                file (e.g. a kernel's
+                <filename>linux-</filename><replaceable>machine</replaceable><filename>.inc</filename>
+                file).
+                In other words, if the build system detects a statement
+                that identifies an "out-of-tree"
+                <filename>defconfig</filename> file, that statement
+                will override your
+                <filename>KBUILD_DEFCONFIG</filename> variable.
+            </para>
+
+            <para>
+                See the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KBUILD_DEFCONFIG'><filename>KBUILD_DEFCONFIG</filename></ulink>
+                variable description for more information.
+            </para>
+        </section>
+    </section>
+
+    <section id="using-devtool-to-patch-the-kernel">
+        <title>Using <filename>devtool</filename> to Patch the Kernel</title>
+
+        <para>
+            The steps in this procedure show you how you can patch the
+            kernel using the extensible SDK and <filename>devtool</filename>.
+            <note>
+                Before attempting this procedure, be sure you have performed
+                the steps to get ready for updating the kernel as described
+                in the
+                "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using <filename>devtool</filename></link>"
+                section.
+            </note>
+        </para>
+
+        <para>
+            Patching the kernel involves changing or adding configurations
+            to an existing kernel, changing or adding recipes to the kernel
+            that are needed to support specific hardware features, or even
+            altering the source code itself.
+        </para>
+
+        <para>
+            This example creates a simple patch by adding some QEMU emulator
+            console output at boot time through <filename>printk</filename>
+            statements in the kernel's <filename>calibrate.c</filename> source
+            code file.
+            Applying the patch and booting the modified image causes the added
+            messages to appear on the emulator's console.
+            The example is a continuation of the setup procedure found in
+            the
+            "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using <filename>devtool</filename></link>"
+            Section.
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Check Out the Kernel Source Files:</emphasis>
+                    First you must use <filename>devtool</filename> to checkout
+                    the kernel source code in its workspace.
+                    Be sure you are in the terminal set up to do work
+                    with the extensible SDK.
+                    <note>
+                        See this
+                        <link linkend='setting-up-the-esdk-terminal'>step</link>
+                        in the
+                        "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using <filename>devtool</filename></link>"
+                        section for more information.
+                    </note>
+                    Use the following <filename>devtool</filename> command
+                    to check out the code:
+                    <literallayout class='monospaced'>
+     $ devtool modify linux-yocto
+                    </literallayout>
+                    <note>
+                        During the checkout operation, a bug exists that could
+                        cause errors such as the following to appear:
+                        <literallayout class='monospaced'>
+     ERROR: Taskhash mismatch 2c793438c2d9f8c3681fd5f7bc819efa versus
+            be3a89ce7c47178880ba7bf6293d7404 for
+            /path/to/esdk/layers/poky/meta/recipes-kernel/linux/linux-yocto_4.10.bb.do_unpack
+                        </literallayout>
+                        You can safely ignore these messages.
+                        The source code is correctly checked out.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Edit the Source Files</emphasis>
+                    Follow these steps to make some simple changes to the source
+                    files:
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>Change the working directory</emphasis>:
+                            In the previous step, the output noted where you can find
+                            the source files (e.g.
+                            <filename>~/poky_sdk/workspace/sources/linux-yocto</filename>).
+                            Change to where the kernel source code is before making
+                            your edits to the <filename>calibrate.c</filename> file:
+                            <literallayout class='monospaced'>
+     $ cd ~/poky_sdk/workspace/sources/linux-yocto
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Edit the source file</emphasis>:
+                            Edit the <filename>init/calibrate.c</filename> file to have
+                            the following changes:
+                            <literallayout class='monospaced'>
+     void calibrate_delay(void)
+     {
+         unsigned long lpj;
+         static bool printed;
+         int this_cpu = smp_processor_id();
+
+         printk("*************************************\n");
+         printk("*                                   *\n");
+         printk("*        HELLO YOCTO KERNEL         *\n");
+         printk("*                                   *\n");
+         printk("*************************************\n");
+
+     	if (per_cpu(cpu_loops_per_jiffy, this_cpu)) {
+               .
+               .
+               .
+                            </literallayout>
+                            </para></listitem>
+                    </orderedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Build the Updated Kernel Source:</emphasis>
+                    To build the updated kernel source, use
+                    <filename>devtool</filename>:
+                    <literallayout class='monospaced'>
+     $ devtool build linux-yocto
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Create the Image With the New Kernel:</emphasis>
+                    Use the <filename>devtool build-image</filename> command
+                    to create a new image that has the new kernel.
+                    <note>
+                        If the image you originally created resulted in a Wic
+                        file, you can use an alternate method to create the new
+                        image with the updated kernel.
+                        For an example, see the steps in the
+                        <ulink url='https://wiki.yoctoproject.org/wiki/TipsAndTricks/KernelDevelopmentWithEsdk'>TipsAndTricks/KernelDevelopmentWithEsdk</ulink>
+                        Wiki Page.
+                    </note>
+                    <literallayout class='monospaced'>
+     $ cd ~
+     $ devtool build-image core-image-minimal
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Test the New Image:</emphasis>
+                    For this example, you can run the new image using QEMU
+                    to verify your changes:
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>Boot the image</emphasis>:
+                            Boot the modified image in the QEMU emulator
+                            using this command:
+                            <literallayout class='monospaced'>
+     $ runqemu qemux86
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Verify the changes</emphasis>:
+                            Log into the machine using <filename>root</filename>
+                            with no password and then use the following shell
+                            command to scroll through the console's boot output.
+                            <literallayout class='monospaced'>
+     # dmesg | less
+                            </literallayout>
+                            You should see the results of your
+                            <filename>printk</filename> statements
+                            as part of the output when you scroll down the
+                            console window.
+                            </para></listitem>
+                    </orderedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Stage and commit your changes</emphasis>:
+                    Within your eSDK terminal, change your working directory to
+                    where you modified the <filename>calibrate.c</filename>
+                    file and use these Git commands to stage and commit your
+                    changes:
+                    <literallayout class='monospaced'>
+     $ cd ~/poky_sdk/workspace/sources/linux-yocto
+     $ git status
+     $ git add init/calibrate.c
+     $ git commit -m "calibrate: Add printk example"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Export the Patches and Create an Append File:</emphasis>
+                    To export your commits as patches and create a
+                    <filename>.bbappend</filename> file, use the following
+                    command in the terminal used to work with the extensible
+                    SDK.
+                    This example uses the previously established layer named
+                    <filename>meta-mylayer</filename>.
+                    <note>
+                        See Step 3 of the
+                        "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using devtool</link>"
+                        section for information on setting up this layer.
+                    </note>
+                    <literallayout class='monospaced'>
+     $ devtool finish linux-yocto ~/meta-mylayer
+                    </literallayout>
+                    Once the command finishes, the patches and the
+                    <filename>.bbappend</filename> file are located in the
+                    <filename>~/meta-mylayer/recipes-kernel/linux</filename>
+                    directory.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Build the Image With Your Modified Kernel:</emphasis>
+                    You can now build an image that includes your kernel
+                    patches.
+                    Execute the following command from your
+                    <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+                    in the terminal set up to run BitBake:
+                    <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake core-image-minimal
+                    </literallayout>
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id="using-traditional-kernel-development-to-patch-the-kernel">
+        <title>Using Traditional Kernel Development to Patch the Kernel</title>
+
+        <para>
+            The steps in this procedure show you how you can patch the
+            kernel using traditional kernel development (i.e. not using
+            <filename>devtool</filename> and the extensible SDK as
+            described in the
+            "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+            section).
+            <note>
+                Before attempting this procedure, be sure you have performed
+                the steps to get ready for updating the kernel as described
+                in the
+                "<link linkend='getting-ready-for-traditional-kernel-development'>Getting Ready for Traditional Kernel Development</link>"
+                section.
+            </note>
+        </para>
+
+        <para>
+            Patching the kernel involves changing or adding configurations
+            to an existing kernel, changing or adding recipes to the kernel
+            that are needed to support specific hardware features, or even
+            altering the source code itself.
+        </para>
+
+        <para>
+            The example in this section creates a simple patch by adding some
+            QEMU emulator console output at boot time through
+            <filename>printk</filename> statements in the kernel's
+            <filename>calibrate.c</filename> source code file.
+            Applying the patch and booting the modified image causes the added
+            messages to appear on the emulator's console.
+            The example is a continuation of the setup procedure found in
+            the
+            "<link linkend='getting-ready-for-traditional-kernel-development'>Getting Ready for Traditional Kernel Development</link>"
+            Section.
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Edit the Source Files</emphasis>
+                    Prior to this step, you should have used Git to create a
+                    local copy of the repository for your kernel.
+                    Assuming you created the repository as directed in the
+                    "<link linkend='getting-ready-for-traditional-kernel-development'>Getting Ready for Traditional Kernel Development</link>"
+                    section, use the following commands to edit the
+                    <filename>calibrate.c</filename> file:
+                    <orderedlist>
+                        <listitem><para>
+                            <emphasis>Change the working directory</emphasis>:
+                            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 <filename>calibrate.c</filename> file:
+                            <literallayout class='monospaced'>
+     $ cd ~/linux-yocto-4.12/init
+                            </literallayout>
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Edit the source file</emphasis>:
+                            Edit the <filename>calibrate.c</filename> file to have
+                            the following changes:
+                            <literallayout class='monospaced'>
+     void calibrate_delay(void)
+     {
+         unsigned long lpj;
+         static bool printed;
+         int this_cpu = smp_processor_id();
+
+         printk("*************************************\n");
+         printk("*                                   *\n");
+         printk("*        HELLO YOCTO KERNEL         *\n");
+         printk("*                                   *\n");
+         printk("*************************************\n");
+
+     	if (per_cpu(cpu_loops_per_jiffy, this_cpu)) {
+               .
+               .
+               .
+                            </literallayout>
+                            </para></listitem>
+                    </orderedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Stage and Commit Your Changes:</emphasis>
+                    Use standard Git commands to stage and commit the changes
+                    you just made:
+                    <literallayout class='monospaced'>
+     $ git add calibrate.c
+     $ git commit -m "calibrate.c - Added some printk statements"
+                    </literallayout>
+                    If you do not stage and commit your changes, the OpenEmbedded
+                    Build System will not pick up the changes.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Update Your <filename>local.conf</filename> File
+                    to Point to Your Source Files:</emphasis>
+                    In addition to your <filename>local.conf</filename> file
+                    specifying to use "kernel-modules" and the "qemux86"
+                    machine, it must also point to the updated kernel source
+                    files.
+                    Add
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>
+                    statements similar to the following to your
+                    <filename>local.conf</filename>:
+                    <literallayout class='monospaced'>
+     $ cd ~/poky/build/conf
+                    </literallayout>
+                    Add the following to the <filename>local.conf</filename>:
+                    <literallayout class='monospaced'>
+     SRC_URI_pn-linux-yocto = "git:///<replaceable>path-to</replaceable>/linux-yocto-4.12;protocol=file;name=machine;branch=standard/base; \
+                               git:///<replaceable>path-to</replaceable>/yocto-kernel-cache;protocol=file;type=kmeta;name=meta;branch=yocto-4.12;destsuffix=${KMETA}"
+     SRCREV_meta_qemux86 = "${AUTOREV}"
+     SRCREV_machine_qemux86 = "${AUTOREV}"
+                    </literallayout>
+                    <note>
+                        Be sure to replace
+                        <replaceable>path-to</replaceable> with the pathname
+                        to your local Git repositories.
+                        Also, you must be sure to specify the correct branch
+                        and machine types.
+                        For this example, the branch is
+                        <filename>standard/base</filename> and the machine is
+                        "qemux86".
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Build the Image:</emphasis>
+                    With the source modified, your changes staged and
+                    committed, and the <filename>local.conf</filename> file
+                    pointing to the kernel files, you can now use BitBake to
+                    build the image:
+                    <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake core-image-minimal
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Boot the image</emphasis>:
+                    Boot the modified image in the QEMU emulator
+                    using this command.
+                    When prompted to login to the QEMU console, use "root"
+                    with no password:
+                    <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ runqemu qemux86
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Look for Your Changes:</emphasis>
+                    As QEMU booted, you might have seen your changes rapidly
+                    scroll by.
+                    If not, use these commands to see your changes:
+                    <literallayout class='monospaced'>
+     # dmesg | less
+                    </literallayout>
+                    You should see the results of your
+                    <filename>printk</filename> statements
+                    as part of the output when you scroll down the
+                    console window.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Generate the Patch File:</emphasis>
+                    Once you are sure that your patch works correctly, you
+                    can generate a <filename>*.patch</filename> file in the
+                    kernel source repository:
+                    <literallayout class='monospaced'>
+     $ cd ~/linux-yocto-4.12/init
+     $ git format-patch -1
+     0001-calibrate.c-Added-some-printk-statements.patch
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Move the Patch File to Your Layer:</emphasis>
+                    In order for subsequent builds to pick up patches, you
+                    need to move the patch file you created in the previous
+                    step to your layer <filename>meta-mylayer</filename>.
+                    For this example, the layer created earlier is located
+                    in your home directory as <filename>meta-mylayer</filename>.
+                    When the layer was created using the
+                    <filename>yocto-create</filename> 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:
+                    <literallayout class='monospaced'>
+     $ cd ~/meta-mylayer
+     $ mkdir recipes-kernel
+     $ mkdir recipes-kernel/linux
+     $ mkdir recipes-kernel/linux/linux-yocto
+                    </literallayout>
+                    Once you have created this hierarchy in your layer, you can
+                    move the patch file using the following command:
+                    <literallayout class='monospaced'>
+     $ mv ~/linux-yocto-4.12/init/0001-calibrate.c-Added-some-printk-statements.patch ~/meta-mylayer/recipes-kernel/linux/linux-yocto
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Create the Append File:</emphasis>
+                    Finally, you need to create the
+                    <filename>linux-yocto_4.12.bbappend</filename> file and
+                    insert statements that allow the OpenEmbedded build
+                    system to find the patch.
+                    The append file needs to be in your layer's
+                    <filename>recipes-kernel/linux</filename>
+                    directory and it must be named
+                    <filename>linux-yocto_4.12.bbappend</filename> and have
+                    the following contents:
+                    <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+
+     SRC_URI_append = " file://0001-calibrate.c-Added-some-printk-statements.patch"
+                    </literallayout>
+                    The
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                    and
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    statements enable the OpenEmbedded build system to find
+                    the patch file.</para>
+
+                    <para>For more information on append files and patches,
+                    see the
+                    "<link linkend='creating-the-append-file'>Creating the Append File</link>"
+                    and
+                    "<link linkend='applying-patches'>Applying Patches</link>"
+                    sections.
+                    You can also see the
+                    "<ulink url='&YOCTO_DOCS_DEV_URL;#using-bbappend-files'>Using .bbappend Files in Your Layer"</ulink>"
+                    section in the Yocto Project Development Tasks Manual.
+                    <note>
+                        To build <filename>core-image-minimal</filename>
+                        again and see the effects of your patch, you can
+                        essentially eliminate the temporary source files
+                        saved in <filename>poky/build/tmp/work/...</filename>
+                        and residual effects of the build by entering the
+                        following sequence of commands:
+                        <literallayout class='monospaced'>
+     $ cd ~/poky/build
+     $ bitbake -c cleanall yocto-linux
+     $ bitbake core-image-minimal -c cleanall
+     $ bitbake core-image-minimal
+     $ runqemu qemux86
+                        </literallayout>
+                    </note>
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id='configuring-the-kernel'>
+        <title>Configuring the Kernel</title>
+
+        <para>
+            Configuring the Yocto Project kernel consists of making sure the
+            <filename>.config</filename> file has all the right information
+            in it for the image you are building.
+            You can use the <filename>menuconfig</filename> tool and
+            configuration fragments to make sure your
+            <filename>.config</filename> file is just how you need it.
+            You can also save known configurations in a
+            <filename>defconfig</filename> file that the build system can use
+            for kernel configuration.
+        </para>
+
+        <para>
+            This section describes how to use <filename>menuconfig</filename>,
+            create and use configuration fragments, and how to interactively
+            modify your <filename>.config</filename> file to create the
+            leanest kernel configuration file possible.
+        </para>
+
+        <para>
+            For more information on kernel configuration, see the
+            "<link linkend='changing-the-configuration'>Changing the Configuration</link>"
+            section.
+        </para>
+
+        <section id='using-menuconfig'>
+            <title>Using&nbsp;&nbsp;<filename>menuconfig</filename></title>
+
+            <para>
+                The easiest way to define kernel configurations is to set
+                them through the <filename>menuconfig</filename> tool.
+                This tool provides an interactive method with which
+                to set kernel configurations.
+                For general information on <filename>menuconfig</filename>, see
+                <ulink url='http://en.wikipedia.org/wiki/Menuconfig'></ulink>.
+            </para>
+
+            <para>
+                To use the <filename>menuconfig</filename> tool in the Yocto
+                Project development environment, you must do the following:
+                <itemizedlist>
+                    <listitem><para>
+                        Because you launch <filename>menuconfig</filename>
+                        using BitBake, you must be sure to set up your
+                        environment by running the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>
+                        script found in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        You must be sure of the state of your build's
+                        configuration in the
+                        <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
+                        </para></listitem>
+                    <listitem><para>
+                        Your build host must have the following two packages
+                        installed:
+                        <literallayout class='monospaced'>
+     libncurses5-dev
+     libtinfo-dev
+                        </literallayout>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                The following commands initialize the BitBake environment,
+                run the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-kernel_configme'><filename>do_kernel_configme</filename></ulink>
+                task, and launch <filename>menuconfig</filename>.
+                These commands assume the Source Directory's top-level folder
+                is <filename>~/poky</filename>:
+                <literallayout class='monospaced'>
+     $ cd poky
+     $ source oe-init-build-env
+     $ bitbake linux-yocto -c kernel_configme -f
+     $ bitbake linux-yocto -c menuconfig
+                </literallayout>
+                Once <filename>menuconfig</filename> comes up, its standard
+                interface allows you to interactively examine and configure
+                all the kernel configuration parameters.
+                After making your changes, simply exit the tool and save your
+                changes to create an updated version of the
+                <filename>.config</filename> configuration file.
+                <note>
+                    You can use the entire <filename>.config</filename> file
+                    as the <filename>defconfig</filename> file.
+                    For information on <filename>defconfig</filename> files,
+                    see the
+                    "<link linkend='changing-the-configuration'>Changing the Configuration</link>",
+                    "<link linkend='using-an-in-tree-defconfig-file'>Using an In-Tree <filename>defconfig</filename> File</link>,
+                    and
+                    "<link linkend='creating-a-defconfig-file'>Creating a <filename>defconfig</filename> File</link>"
+                    sections.
+                </note>
+            </para>
+
+            <para>
+                Consider an example that configures the "CONFIG_SMP" setting
+                for the <filename>linux-yocto-4.12</filename> kernel.
+                <note>
+                    The OpenEmbedded build system recognizes this kernel as
+                    <filename>linux-yocto</filename> through Metadata (e.g.
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-PREFERRED_VERSION'><filename>PREFERRED_VERSION</filename></ulink><filename>_linux-yocto ?= "12.4%"</filename>).
+                </note>
+                Once <filename>menuconfig</filename> launches, use the
+                interface to navigate through the selections to find the
+                configuration settings in which you are interested.
+                For this example, you deselect "CONFIG_SMP" by clearing the
+                "Symmetric Multi-Processing Support" option.
+                Using the interface, you can find the option under
+                "Processor Type and Features".
+                To deselect "CONFIG_SMP", use the arrow keys to
+                highlight "Symmetric Multi-Processing Support" and enter "N"
+                to clear the asterisk.
+                When you are finished, exit out and save the change.
+            </para>
+
+            <para>
+                Saving the selections updates the <filename>.config</filename>
+                configuration file.
+                This is the file that the OpenEmbedded build system uses to
+                configure the kernel during the build.
+                You can find and examine this file in the Build Directory in
+                <filename>tmp/work/</filename>.
+                The actual <filename>.config</filename> is located in the
+                area where the specific kernel is built.
+                For example, if you were building a Linux Yocto kernel based
+                on the <filename>linux-yocto-4.12</filename> kernel and you
+                were building a QEMU image targeted for
+                <filename>x86</filename> architecture, the
+                <filename>.config</filename> file would be:
+                <literallayout class='monospaced'>
+     poky/build/tmp/work/qemux86-poky-linux/linux-yocto/4.12.12+gitAUTOINC+eda4d18...
+     ...967-r0/linux-qemux86-standard-build/.config
+                </literallayout>
+                <note>
+                    The previous example directory is artificially split and
+                    many of the characters in the actual filename are omitted
+                    in order to make it more readable.
+                    Also, depending on the kernel you are using, the exact
+                    pathname might differ.
+                </note>
+            </para>
+
+            <para>
+                Within the <filename>.config</filename> file, you can see the
+                kernel settings.
+                For example, the following entry shows that symmetric
+                multi-processor support is not set:
+                <literallayout class='monospaced'>
+     # CONFIG_SMP is not set
+                </literallayout>
+            </para>
+
+            <para>
+                A good method to isolate changed configurations is to use a
+                combination of the <filename>menuconfig</filename> tool and
+                simple shell commands.
+                Before changing configurations with
+                <filename>menuconfig</filename>, copy the existing
+                <filename>.config</filename> and rename it to something else,
+                use <filename>menuconfig</filename> to make as many changes as
+                you want and save them, then compare the renamed configuration
+                file against the newly created file.
+                You can use the resulting differences as your base to create
+                configuration fragments to permanently save in your kernel
+                layer.
+                <note>
+                    Be sure to make a copy of the <filename>.config</filename>
+                    file and do not just rename it.
+                    The build system needs an existing
+                    <filename>.config</filename> file from which to work.
+                </note>
+            </para>
+        </section>
+
+        <section id='creating-a-defconfig-file'>
+            <title>Creating a&nbsp;&nbsp;<filename>defconfig</filename> File</title>
+
+            <para>
+                A <filename>defconfig</filename> file in the context of
+                the Yocto Project is often a <filename>.config</filename>
+                file that is copied from a build or a
+                <filename>defconfig</filename> taken from the kernel tree
+                and moved into recipe space.
+                You can use a <filename>defconfig</filename> file
+                to retain a known set of kernel configurations from which the
+                OpenEmbedded build system can draw to create the final
+                <filename>.config</filename> file.
+                <note>
+                    Out-of-the-box, the Yocto Project never ships a
+                    <filename>defconfig</filename> or
+                    <filename>.config</filename> file.
+                    The OpenEmbedded build system creates the final
+                    <filename>.config</filename> file used to configure the
+                    kernel.
+                </note>
+            </para>
+
+            <para>
+                To create a <filename>defconfig</filename>, start with a
+                complete, working Linux kernel <filename>.config</filename>
+                file.
+                Copy that file to the appropriate
+                <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
+                directory in your layer's
+                <filename>recipes-kernel/linux</filename> directory, and rename
+                the copied file to "defconfig" (e.g.
+                <filename>~/meta-mylayer/recipes-kernel/linux/linux-yocto/defconfig</filename>).
+                Then, add the following lines to the linux-yocto
+                <filename>.bbappend</filename> file in your layer:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+     SRC_URI += "file://defconfig"
+                </literallayout>
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                tells the build system how to search for the file, while the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESEXTRAPATHS'><filename>FILESEXTRAPATHS</filename></ulink>
+                extends the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-FILESPATH'><filename>FILESPATH</filename></ulink>
+                variable (search directories) to include the
+                <filename>${PN}</filename> directory you created to hold the
+                configuration changes.
+                <note>
+                    The build system applies the configurations from the
+                    <filename>defconfig</filename> file before applying any
+                    subsequent configuration fragments.
+                    The final kernel configuration is a combination of the
+                    configurations in the <filename>defconfig</filename>
+                    file and any configuration fragments you provide.
+                    You need to realize that if you have any configuration
+                    fragments, the build system applies these on top of and
+                    after applying the existing defconfig file configurations.
+                </note>
+                For more information on configuring the kernel, see the
+                "<link linkend='changing-the-configuration'>Changing the Configuration</link>"
+                section.
+            </para>
+        </section>
+
+        <section id='creating-config-fragments'>
+            <title>Creating Configuration Fragments</title>
+
+            <para>
+                Configuration fragments are simply kernel options that
+                appear in a file placed where the OpenEmbedded build system
+                can find and apply them.
+                The build system applies configuration fragments after
+                applying configurations from a <filename>defconfig</filename>
+                file.
+                Thus, the final kernel configuration is a combination of the
+                configurations in the <filename>defconfig</filename>
+                file and then any configuration fragments you provide.
+                The build system applies fragments on top of and
+                after applying the existing defconfig file configurations.
+            </para>
+
+            <para>
+                Syntactically, the configuration statement is identical to
+                what would appear in the <filename>.config</filename> file,
+                which is in the
+                <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
+                <note>
+                    For more information about where the
+                    <filename>.config</filename> file is located, see the
+                    example in the
+                    "<link linkend='using-menuconfig'>Using <filename>menuconfig</filename></link>"
+                    section.
+                </note>
+            </para>
+
+            <para>
+                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
+                <filename>my_smp.cfg</filename> that enables multi-processor
+                support within the kernel:
+                <literallayout class='monospaced'>
+     $ echo "CONFIG_SMP=y" >> my_smp.cfg
+                </literallayout>
+                <note>
+                    All configuration fragment files must use the
+                    <filename>.cfg</filename> extension in order for the
+                    OpenEmbedded build system to recognize them as a
+                    configuration fragment.
+                </note>
+            </para>
+
+            <para>
+                Another method is to create a configuration fragment using the
+                differences between two configuration files: one previously
+                created and saved, and one freshly created using the
+                <filename>menuconfig</filename> tool.
+            </para>
+
+            <para>
+                To create a configuration fragment using this method, follow
+                these steps:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Complete a Build Through Kernel Configuration:</emphasis>
+                        Complete a build at least through the kernel
+                        configuration task as follows:
+                        <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c kernel_configme -f
+                        </literallayout>
+                        This step ensures that you create a
+                        <filename>.config</filename> file from a known state.
+                        Because situations exist where your build state might
+                        become unknown, it is best to run this task prior
+                        to starting <filename>menuconfig</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Launch <filename>menuconfig</filename>:</emphasis>
+                        Run the <filename>menuconfig</filename> command:
+                        <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c menuconfig
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Create the Configuration Fragment:</emphasis>
+                        Run the <filename>diffconfig</filename>
+                        command to prepare a configuration fragment.
+                        The resulting file <filename>fragment.cfg</filename>
+                        is placed in the
+                        <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-WORKDIR'><filename>WORKDIR</filename></ulink><filename>}</filename> directory:
+                        <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c diffconfig
+                        </literallayout>
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                The <filename>diffconfig</filename> command creates a file
+                that is a list of Linux kernel <filename>CONFIG_</filename>
+                assignments.
+                See the "<link linkend='changing-the-configuration'>Changing the Configuration</link>"
+                section for additional information on how to use the output
+                as a configuration fragment.
+                <note>
+                    You can also use this method to create configuration
+                    fragments for a BSP.
+                    See the "<link linkend='bsp-descriptions'>BSP Descriptions</link>"
+                    section for more information.
+                </note>
+            </para>
+
+            <para>
+                Where do you put your configuration fragment files?
+                You can place these files in an area pointed to by
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                as directed by your <filename>bblayers.conf</filename> file,
+                which is located in your layer.
+                The OpenEmbedded build system picks up the configuration and
+                adds it to the kernel's configuration.
+                For example, suppose you had a set of configuration options
+                in a file called <filename>myconfig.cfg</filename>.
+                If you put that file inside a directory named
+                <filename>linux-yocto</filename> 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:
+                <literallayout class='monospaced'>
+     FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+     SRC_URI += "file://myconfig.cfg"
+                </literallayout>
+            </para>
+
+            <para>
+                As mentioned earlier, you can group related configurations
+                into multiple files and name them all in the
+                <filename>SRC_URI</filename> 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 <filename>SRC_URI</filename> statement
+                like the following in your append file:
+                <literallayout class='monospaced'>
+     SRC_URI += "file://myconfig.cfg \
+            file://eth.cfg \
+            file://gfx.cfg"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='validating-configuration'>
+            <title>Validating Configuration</title>
+
+            <para>
+                You can use the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-kernel_configcheck'><filename>do_kernel_configcheck</filename></ulink>
+                task to provide configuration validation:
+                <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c kernel_configcheck -f
+                </literallayout>
+                Running this task produces warnings for when a
+                requested configuration does not appear in the final
+                <filename>.config</filename> file or when you override a
+                policy configuration in a hardware configuration fragment.
+            </para>
+
+            <para>
+                In order to run this task, you must have an existing
+                <filename>.config</filename> file.
+                See the
+                "<link linkend='using-menuconfig'>Using <filename>menuconfig</filename></link>"
+                section for information on how to create a configuration file.
+            </para>
+
+            <para>
+                Following is sample output from the
+                <filename>do_kernel_configcheck</filename> task:
+                <literallayout class='monospaced'>
+     Loading cache: 100% |########################################################| Time: 0:00:00
+     Loaded 1275 entries from dependency cache.
+     NOTE: Resolving any missing task queue dependencies
+
+     Build Configuration:
+         .
+         .
+         .
+
+     NOTE: Executing SetScene Tasks
+     NOTE: Executing RunQueue Tasks
+     WARNING: linux-yocto-4.12.12+gitAUTOINC+eda4d18ce4_16de014967-r0 do_kernel_configcheck:
+         [kernel config]: specified values did not make it into the kernel's final configuration:
+
+     ---------- CONFIG_X86_TSC -----------------
+     Config: CONFIG_X86_TSC
+     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc-cpu.cfg
+     Requested value:  CONFIG_X86_TSC=y
+     Actual value:
+
+
+     ---------- CONFIG_X86_BIGSMP -----------------
+     Config: CONFIG_X86_BIGSMP
+     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
+           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
+     Requested value:  # CONFIG_X86_BIGSMP is not set
+     Actual value:
+
+
+     ---------- CONFIG_NR_CPUS -----------------
+     Config: CONFIG_NR_CPUS
+     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
+           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc.cfg
+           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
+     Requested value:  CONFIG_NR_CPUS=8
+     Actual value:     CONFIG_NR_CPUS=1
+
+
+     ---------- CONFIG_SCHED_SMT -----------------
+     Config: CONFIG_SCHED_SMT
+     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
+           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
+     Requested value:  CONFIG_SCHED_SMT=y
+     Actual value:
+
+
+
+     NOTE: Tasks Summary: Attempted 288 tasks of which 285 didn't need to be rerun and all succeeded.
+
+     Summary: There were 3 WARNING messages shown.
+                </literallayout>
+                <note>
+                    The previous output example has artificial line breaks
+                    to make it more readable.
+                </note>
+            </para>
+
+            <para>
+                The output describes the various problems that you can
+                encounter along with where to find the offending configuration
+                items.
+                You can use the information in the logs to adjust your
+                configuration files and then repeat the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-kernel_configme'><filename>do_kernel_configme</filename></ulink>
+                and
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-kernel_configcheck'><filename>do_kernel_configcheck</filename></ulink>
+                tasks until they produce no warnings.
+            </para>
+
+            <para>
+                For more information on how to use the
+                <filename>menuconfig</filename> tool, see the
+                "<link linkend='using-menuconfig'>Using <filename>menuconfig</filename></link>"
+                section.
+            </para>
+        </section>
+
+        <section id='fine-tuning-the-kernel-configuration-file'>
+            <title>Fine-Tuning the Kernel Configuration File</title>
+
+            <para>
+                You can make sure the <filename>.config</filename> file is as
+                lean or efficient as possible by reading the output of the
+                kernel configuration fragment audit, noting any issues, making
+                changes to correct the issues, and then repeating.
+            </para>
+
+            <para>
+                As part of the kernel build process, the
+                <filename>do_kernel_configcheck</filename> task runs.
+                This task validates the kernel configuration by checking the
+                final <filename>.config</filename> file against the input
+                files.
+                During the check, the task produces warning messages for the
+                following issues:
+                <itemizedlist>
+                    <listitem><para>
+                        Requested options that did not make the final
+                        <filename>.config</filename> file.
+                        </para></listitem>
+                    <listitem><para>
+                        Configuration items that appear twice in the same
+                        configuration fragment.
+                        </para></listitem>
+                    <listitem><para>
+                        Configuration items tagged as "required" that were
+                        overridden.
+                        </para></listitem>
+                    <listitem><para>
+                        A board overrides a non-board specific option.
+                        </para></listitem>
+                    <listitem><para>
+                        Listed options not valid for the kernel being
+                        processed.
+                        In other words, the option does not appear anywhere.
+                        </para></listitem>
+                </itemizedlist>
+                <note>
+                    The <filename>do_kernel_configcheck</filename> task can
+                    also optionally report if an option is overridden during
+                    processing.
+                </note>
+            </para>
+
+            <para>
+                For each output warning, a message points to the file
+                that contains a list of the options and a pointer to the
+                configuration fragment that defines them.
+                Collectively, the files are the key to streamlining the
+                configuration.
+            </para>
+
+            <para>
+                To streamline the configuration, do the following:
+                <orderedlist>
+                    <listitem><para>
+                        <emphasis>Use a Working Configuration:</emphasis>
+                        Start with a full configuration that you
+                        know works.
+                        Be sure the configuration builds and boots
+                        successfully.
+                        Use this configuration file as your baseline.
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Run Configure and Check Tasks:</emphasis>
+                        Separately run the
+                        <filename>do_kernel_configme</filename> and
+                        <filename>do_kernel_configcheck</filename> tasks:
+                        <literallayout class='monospaced'>
+     $ bitbake linux-yocto -c kernel_configme -f
+     $ bitbake linux-yocto -c kernel_configcheck -f
+                        </literallayout>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Process the Results:</emphasis>
+                        Take the resulting list of files from the
+                        <filename>do_kernel_configcheck</filename> task
+                        warnings and do the following:
+                        <itemizedlist>
+                            <listitem><para>
+                                Drop values that are redefined in the fragment
+                                but do not change the final
+                                <filename>.config</filename> file.
+                                </para></listitem>
+                            <listitem><para>
+                                Analyze and potentially drop values from the
+                                <filename>.config</filename> file that override
+                                required configurations.
+                                </para></listitem>
+                            <listitem><para>
+                                Analyze and potentially remove non-board
+                                specific options.
+                                </para></listitem>
+                            <listitem><para>
+                                Remove repeated and invalid options.
+                                </para></listitem>
+                        </itemizedlist>
+                        </para></listitem>
+                    <listitem><para>
+                        <emphasis>Re-Run Configure and Check Tasks:</emphasis>
+                        After you have worked through the output of the kernel
+                        configuration audit, you can re-run the
+                        <filename>do_kernel_configme</filename> and
+                        <filename>do_kernel_configcheck</filename> tasks to
+                        see the results of your changes.
+                        If you have more issues, you can deal with them as
+                        described in the previous step.
+                        </para></listitem>
+                </orderedlist>
+            </para>
+
+            <para>
+                Iteratively working through steps two through four eventually
+                yields a minimal, streamlined configuration file.
+                Once you have the best <filename>.config</filename>, you can
+                build the Linux Yocto kernel.
+            </para>
+        </section>
+    </section>
+
+    <section id='expanding-variables'>
+        <title>Expanding Variables</title>
+
+        <para>
+            Sometimes it is helpful to determine what a variable expands
+            to during a build.
+            You can do examine the values of variables by examining the
+            output of the <filename>bitbake -e</filename> command.
+            The output is long and is more easily managed in a text file,
+            which allows for easy searches:
+            <literallayout class='monospaced'>
+     $ bitbake -e virtual/kernel > <replaceable>some_text_file</replaceable>
+            </literallayout>
+            Within the text file, you can see exactly how each variable is
+            expanded and used by the OpenEmbedded build system.
+        </para>
+    </section>
+
+    <section id='working-with-a-dirty-kernel-version-string'>
+        <title>Working with a "Dirty" Kernel Version String</title>
+
+        <para>
+            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 source directory.
+            Follow these steps to clean up the version string:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Discover the Uncommitted Changes:</emphasis>
+                    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:
+                    <literallayout class='monospaced'>
+     $ git status
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Commit the Changes:</emphasis>
+                    You should commit those changes to the kernel source
+                    tree regardless of whether or not you will save,
+                    export, or use the changes:
+                    <literallayout class='monospaced'>
+     $ git add
+     $ git commit -s -a -m "getting rid of -dirty"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Rebuild the Kernel Image:</emphasis>
+                    Once you commit the changes, rebuild the kernel.</para>
+
+                    <para>Depending on your particular kernel development
+                    workflow, the commands you use to rebuild the
+                    kernel might differ.
+                    For information on building the kernel image when
+                    using <filename>devtool</filename>, see the
+                    "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+                    section.
+                    For information on building the kernel image when
+                    using Bitbake, see the
+                    "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+                    section.
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id='working-with-your-own-sources'>
+        <title>Working With Your Own Sources</title>
+
+        <para>
+            If you cannot work with one of the Linux kernel
+            versions supported by existing linux-yocto recipes, you can
+            still make use of the Yocto Project Linux kernel tooling by
+            working with your own sources.
+            When you use your own sources, you will not be able to
+            leverage the existing kernel
+            <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink> and
+            stabilization work of the linux-yocto sources.
+            However, you will be able to manage your own Metadata in the same
+            format as the linux-yocto sources.
+            Maintaining format compatibility facilitates converging with
+            linux-yocto on a future, mutually-supported kernel version.
+        </para>
+
+        <para>
+            To help you use your own sources, the Yocto Project provides a
+            linux-yocto custom recipe
+            (<filename>linux-yocto-custom.bb</filename>) that uses
+            <filename>kernel.org</filename> sources
+            and the Yocto Project Linux kernel tools for managing
+            kernel Metadata.
+            You can find this recipe in the
+            <filename>poky</filename> Git repository of the
+            Yocto Project <ulink url='&YOCTO_GIT_URL;'>Source Repository</ulink>
+            at:
+            <literallayout class="monospaced">
+     poky/meta-skeleton/recipes-kernel/linux/linux-yocto-custom.bb
+            </literallayout>
+        </para>
+
+        <para>
+            Here are some basic steps you can use to work with your own
+            sources:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Create a Copy of the Kernel Recipe:</emphasis>
+                    Copy the <filename>linux-yocto-custom.bb</filename>
+                    recipe to your layer and give it a meaningful name.
+                    The name should include the version of the Yocto Linux
+                    kernel you are using (e.g.
+                    <filename>linux-yocto-myproject_4.12.bb</filename>,
+                    where "4.12" is the base version of the Linux kernel
+                    with which you would be working).
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Create a Directory for Your Patches:</emphasis>
+                    In the same directory inside your layer, create a matching
+                    directory to store your patches and configuration files
+                    (e.g. <filename>linux-yocto-myproject</filename>).
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Ensure You Have Configurations:</emphasis>
+                    Make sure you have either a <filename>defconfig</filename>
+                    file or configuration fragment files in your layer.
+                    When you use the <filename>linux-yocto-custom.bb</filename>
+                    recipe, you must specify a configuration.
+                    If you do not have a <filename>defconfig</filename> file,
+                    you can run the following:
+                    <literallayout class='monospaced'>
+     $ make defconfig
+                    </literallayout>
+                    After running the command, copy the resulting
+                    <filename>.config</filename> file to the
+                    <filename>files</filename> directory in your layer
+                    as "defconfig" and then add it to the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                    variable in the recipe.</para>
+
+                    <para>Running the <filename>make defconfig</filename>
+                    command results in the default configuration for your
+                    architecture as defined by your kernel.
+                    However, no guarantee exists that this configuration is
+                    valid for your use case, or that your board will even boot.
+                    This is particularly true for non-x86 architectures.</para>
+
+                    <para>To use non-x86 <filename>defconfig</filename> files,
+                    you need to be more specific and find one that matches your
+                    board (i.e. for arm, you look in
+                    <filename>arch/arm/configs</filename> and use the one that
+                    is the best starting point for your board).
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Edit the Recipe:</emphasis>
+                    Edit the following variables in your recipe as appropriate
+                    for your project:
+                    <itemizedlist>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>:
+                            The <filename>SRC_URI</filename> should specify
+                            a Git repository that uses one of the supported Git
+                            fetcher protocols (i.e. <filename>file</filename>,
+                            <filename>git</filename>, <filename>http</filename>,
+                            and so forth).
+                            The <filename>SRC_URI</filename> variable should
+                            also specify either a <filename>defconfig</filename>
+                            file or some configuration fragment files.
+                            The skeleton recipe provides an example
+                            <filename>SRC_URI</filename> as a syntax reference.
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-LINUX_VERSION'><filename>LINUX_VERSION</filename></ulink>:
+                            The Linux kernel version you are using (e.g.
+                            "4.12").
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-LINUX_VERSION_EXTENSION'><filename>LINUX_VERSION_EXTENSION</filename></ulink>:
+                            The Linux kernel
+                            <filename>CONFIG_LOCALVERSION</filename> that is
+                            compiled into the resulting kernel and visible
+                            through the <filename>uname</filename> command.
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCREV'><filename>SRCREV</filename></ulink>:
+                            The commit ID from which you want to build.
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>:
+                            Treat this variable the same as you would in any
+                            other recipe.
+                            Increment the variable to indicate to the
+                            OpenEmbedded build system that the recipe has
+                            changed.
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>:
+                            The default <filename>PV</filename> assignment is
+                            typically adequate.
+                            It combines the <filename>LINUX_VERSION</filename>
+                            with the Source Control Manager (SCM) revision
+                            as derived from the
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRCPV'><filename>SRCPV</filename></ulink>
+                            variable.
+                            The combined results are a string with the
+                            following form:
+                            <literallayout class='monospaced'>
+     3.19.11+git1+68a635bf8dfb64b02263c1ac80c948647cc76d5f_1+218bd8d2022b9852c60d32f0d770931e3cf343e2
+                            </literallayout>
+                            While lengthy, the extra verbosity in
+                            <filename>PV</filename> helps ensure you are using
+                            the exact sources from which you intend to build.
+                            </para></listitem>
+                        <listitem><para>
+                            <ulink url='&YOCTO_DOCS_REF_URL;#var-COMPATIBLE_MACHINE'><filename>COMPATIBLE_MACHINE</filename></ulink>:
+                            A list of the machines supported by your new recipe.
+                            This variable in the example recipe is set
+                            by default to a regular expression that matches
+                            only the empty string, "(^$)".
+                            This default setting 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
+                            <filename>qemux86</filename> and
+                            <filename>qemux86-64</filename> machines, use
+                            the following form:
+                            <literallayout class='monospaced'>
+     COMPATIBLE_MACHINE = "qemux86|qemux86-64"
+                            </literallayout>
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Customize Your Recipe as Needed:</emphasis>
+                    Provide further customizations to your recipe
+                    as needed just as you would customize an existing
+                    linux-yocto recipe.
+                    See the
+                    "<link linkend='modifying-an-existing-recipe'>Modifying an Existing Recipe</link>"
+                    section for information.
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+
+    <section id='working-with-out-of-tree-modules'>
+        <title>Working with Out-of-Tree Modules</title>
+
+        <para>
+            This section describes steps to build out-of-tree modules on
+            your target and describes how to incorporate out-of-tree modules
+            in the build.
+        </para>
+
+        <section id='building-out-of-tree-modules-on-the-target'>
+            <title>Building Out-of-Tree Modules on the Target</title>
+
+            <para>
+                While the traditional Yocto Project development model would be
+                to include kernel modules as part of the normal build
+                process, you might find it useful to build modules on the
+                target.
+                This could be the case if your target system is capable
+                and powerful enough to handle the necessary compilation.
+                Before deciding to build on your target, however, you should
+                consider the benefits of using a proper cross-development
+                environment from your build host.
+            </para>
+
+            <para>
+                If you want to be able to build out-of-tree modules on
+                the target, there are some steps you need to take
+                on the target that is running your SDK image.
+                Briefly, the <filename>kernel-dev</filename> package
+                is installed by default on all
+                <filename>*.sdk</filename> images and the
+                <filename>kernel-devsrc</filename> package is installed
+                on many of the <filename>*.sdk</filename> images.
+                However, you need to create some scripts prior to
+                attempting to build the out-of-tree modules on the target
+                that is running that image.
+            </para>
+
+            <para>
+                Prior to attempting to build the out-of-tree modules,
+                you need to be on the target as root and you need to
+                change to the <filename>/usr/src/kernel</filename> directory.
+                Next, <filename>make</filename> the scripts:
+                <literallayout class='monospaced'>
+     # cd /usr/src/kernel
+     # make scripts
+                </literallayout>
+                Because all SDK image recipes include
+                <filename>dev-pkgs</filename>, the
+                <filename>kernel-dev</filename> packages will be installed
+                as part of the SDK image and the
+                <filename>kernel-devsrc</filename> packages will be installed
+                as part of applicable SDK images.
+                The SDK uses the scripts when building out-of-tree
+                modules.
+                Once you have switched to that directory and created the
+                scripts, you should be able to build your out-of-tree modules
+                on the target.
+            </para>
+        </section>
+
+        <section id='incorporating-out-of-tree-modules'>
+            <title>Incorporating Out-of-Tree Modules</title>
+
+            <para>
+                While it is always preferable to work with sources integrated
+                into the Linux kernel sources, if you need an external kernel
+                module, the <filename>hello-mod.bb</filename> recipe is
+                available as a template from which you can create your
+                own out-of-tree Linux kernel module recipe.
+            </para>
+
+            <para>
+                This template recipe is located in the
+                <filename>poky</filename> Git repository of the
+                Yocto Project <ulink url='&YOCTO_GIT_URL;'>Source Repository</ulink>
+                at:
+                <literallayout class="monospaced">
+     poky/meta-skeleton/recipes-kernel/hello-mod/hello-mod_0.1.bb
+                </literallayout>
+            </para>
+
+            <para>
+                To get started, copy this recipe to your layer and give it a
+                meaningful name (e.g. <filename>mymodule_1.0.bb</filename>).
+                In the same directory, create a new directory named
+                <filename>files</filename> where you can store any source files,
+                patches, or other files necessary for building
+                the module that do not come with the sources.
+                Finally, update the recipe as needed for the module.
+                Typically, you will need to set the following variables:
+                <itemizedlist>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-DESCRIPTION'><filename>DESCRIPTION</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE*</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Depending on the build system used by the module sources,
+                you might need to make some adjustments.
+                For example, a typical module <filename>Makefile</filename>
+                looks much like the one provided with the
+                <filename>hello-mod</filename> template:
+                <literallayout class='monospaced'>
+     obj-m := hello.o
+
+     SRC := $(shell pwd)
+
+     all:
+         $(MAKE) -C $(KERNEL_SRC) M=$(SRC)
+
+     modules_install:
+         $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install
+     ...
+                </literallayout>
+            </para>
+
+            <para>
+                The important point to note here is the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_SRC'><filename>KERNEL_SRC</filename></ulink>
+                variable.
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-module'><filename>module</filename></ulink>
+                class sets this variable and the
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_PATH'><filename>KERNEL_PATH</filename></ulink>
+                variable to
+                <filename>${<ulink url='&YOCTO_DOCS_REF_URL;#var-STAGING_KERNEL_DIR'><filename>STAGING_KERNEL_DIR</filename></ulink>}</filename>
+                with the necessary Linux kernel build information to build
+                modules.
+                If your module <filename>Makefile</filename> uses a different
+                variable, you might want to override the
+                <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-compile'><filename>do_compile</filename></ulink>
+                step, or create a patch to
+                the <filename>Makefile</filename> to work with the more typical
+                <filename>KERNEL_SRC</filename> or
+                <filename>KERNEL_PATH</filename> variables.
+            </para>
+
+            <para>
+                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 following variables in
+                the Yocto Project Reference Manual and set one of them
+                appropriately for your machine configuration file:
+                <itemizedlist>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RDEPENDS'><filename>MACHINE_EXTRA_RDEPENDS</filename></ulink>
+                        </para></listitem>
+                    <listitem><para><ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RRECOMMENDS'><filename>MACHINE_EXTRA_RRECOMMENDS</filename></ulink>
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+
+            <para>
+                Modules are often not required for boot and can be excluded from
+                certain build configurations.
+                The following allows for the most flexibility:
+                <literallayout class='monospaced'>
+     MACHINE_EXTRA_RRECOMMENDS += "kernel-module-mymodule"
+                </literallayout>
+                The value is derived by appending the module filename without
+                the <filename>.ko</filename> extension to the string
+                "kernel-module-".
+            </para>
+
+            <para>
+                Because the variable is
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>
+                and not a
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>
+                variable, the build will not fail if this module is not
+                available to include in the image.
+            </para>
+        </section>
+    </section>
+
+
+    <section id='inspecting-changes-and-commits'>
+        <title>Inspecting Changes and Commits</title>
+
+        <para>
+            A common question when working with a kernel is:
+            "What changes have been applied to this tree?"
+            Rather than using "grep" across directories to see what has
+            changed, you can use Git to inspect or search the kernel tree.
+            Using Git is an efficient way to see what has changed in the tree.
+        </para>
+
+        <section id='what-changed-in-a-kernel'>
+            <title>What Changed in a Kernel?</title>
+
+            <para>
+                Following are a few examples that show how to use Git
+                commands to examine changes.
+                These examples are by no means the only way to see changes.
+                <note>
+                    In the following examples, unless you provide a commit
+                    range, <filename>kernel.org</filename> history is blended
+                    with Yocto Project kernel changes.
+                    You can form ranges by using branch names from the
+                    kernel tree as the upper and lower commit markers with
+                    the Git commands.
+                    You can see the branch names through the web interface
+                    to the Yocto Project source repositories at
+                    <ulink url='&YOCTO_GIT_URL;'></ulink>.
+                </note>
+                To see a full range of the changes, use the
+                <filename>git whatchanged</filename> command and specify a
+                commit range for the branch
+                (<replaceable>commit</replaceable><filename>..</filename><replaceable>commit</replaceable>).
+            </para>
+
+            <para>
+                Here is an example that looks at what has changed in the
+                <filename>emenlow</filename> branch of the
+                <filename>linux-yocto-3.19</filename> kernel.
+                The lower commit range is the commit associated with the
+                <filename>standard/base</filename> branch, while
+                the upper commit range is the commit associated with the
+                <filename>standard/emenlow</filename> branch.
+                <literallayout class='monospaced'>
+     $ git whatchanged origin/standard/base..origin/standard/emenlow
+                </literallayout>
+            </para>
+
+            <para>
+                To see short, one line summaries of changes use the
+                <filename>git log</filename> command:
+                <literallayout class='monospaced'>
+     $ git log --oneline origin/standard/base..origin/standard/emenlow
+                </literallayout>
+            </para>
+
+            <para>
+                Use this command to see code differences for the changes:
+                <literallayout class='monospaced'>
+     $ git diff origin/standard/base..origin/standard/emenlow
+                </literallayout>
+            </para>
+
+            <para>
+                Use this command to see the commit log messages and the
+                text differences:
+                <literallayout class='monospaced'>
+     $ git show origin/standard/base..origin/standard/emenlow
+                </literallayout>
+            </para>
+
+            <para>
+                Use this command to create individual patches for
+                each change.
+                Here is an example that that creates patch files for each
+                commit and places them in your <filename>Documents</filename>
+                directory:
+                <literallayout class='monospaced'>
+     $ git format-patch -o $HOME/Documents origin/standard/base..origin/standard/emenlow
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='showing-a-particular-feature-or-branch-change'>
+            <title>Showing a Particular Feature or Branch Change</title>
+
+            <para>
+                Tags in the Yocto Project kernel tree divide changes for
+                significant features or branches.
+                The <filename>git show</filename>&nbsp;<replaceable>tag</replaceable>
+                command shows changes based on a tag.
+                Here is an example that shows <filename>systemtap</filename>
+                changes:
+                <literallayout class='monospaced'>
+     $ git show systemtap
+                </literallayout>
+                You can use the
+                <filename>git branch --contains</filename>&nbsp;<replaceable>tag</replaceable>
+                command to show the branches that contain a particular feature.
+                This command shows the branches that contain the
+                <filename>systemtap</filename> feature:
+                <literallayout class='monospaced'>
+     $ git branch --contains systemtap
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='adding-recipe-space-kernel-features'>
+        <title>Adding Recipe-Space Kernel Features</title>
+
+        <para>
+            You can add kernel features in the
+            <link linkend='recipe-space-metadata'>recipe-space</link> by
+            using the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_FEATURES'><filename>KERNEL_FEATURES</filename></ulink>
+            variable and by specifying the feature's <filename>.scc</filename>
+            file path in the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+            statement.
+            When you add features using this method, the OpenEmbedded build
+            system checks to be sure the features are present.
+            If the features are not present, the 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 <filename>SRC_URI</filename> statement.
+        </para>
+
+        <para>
+            You add a kernel feature by providing the feature as part of the
+            <filename>KERNEL_FEATURES</filename> variable and by providing the
+            path to the feature's <filename>.scc</filename> file, which is
+            relative to the root of the kernel Metadata.
+            The OpenEmbedded build system searches all forms of kernel
+            Metadata on the <filename>SRC_URI</filename> 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
+            "<link linkend='kernel-metadata-location'>Kernel Metadata Location</link>"
+            section for additional information.
+        </para>
+
+        <para>
+            When you specify the feature's <filename>.scc</filename> file
+            on the <filename>SRC_URI</filename> statement, the OpenEmbedded
+            build system adds the directory of that
+            <filename>.scc</filename> file along with all its subdirectories
+            to the kernel feature search path.
+            Because subdirectories are searched, you can reference a single
+            <filename>.scc</filename> file in the
+            <filename>SRC_URI</filename> statement to reference multiple kernel
+            features.
+        </para>
+
+        <para>
+            Consider the following example that adds the "test.scc" feature
+            to the build.
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Create the Feature File:</emphasis>
+                    Create a <filename>.scc</filename> file and locate it
+                    just as you would any other patch file,
+                    <filename>.cfg</filename> file, or fetcher item
+                    you specify in the <filename>SRC_URI</filename>
+                    statement.
+                    <note><title>Notes</title>
+                        <itemizedlist>
+                            <listitem><para>
+                                You must add the directory of the
+                                <filename>.scc</filename> file to the fetcher's
+                                search path in the same manner as you would
+                                add a <filename>.patch</filename> file.
+                                </para></listitem>
+                            <listitem><para>
+                                You can create additional
+                                <filename>.scc</filename> files beneath the
+                                directory that contains the file you are
+                                adding.
+                                All subdirectories are searched during the
+                                build as potential feature directories.
+                                </para></listitem>
+                        </itemizedlist>
+                    </note>
+                    Continuing with the example, suppose the "test.scc"
+                    feature you are adding has a
+                    <filename>test.scc</filename> file in the following
+                    directory:
+                    <literallayout class='monospaced'>
+     <replaceable>my_recipe</replaceable>
+        |
+        +-linux-yocto
+           |
+           +-test.cfg
+           +-test.scc
+                    </literallayout>
+                    In this example, the <filename>linux-yocto</filename>
+                    directory has both the feature
+                    <filename>test.scc</filename> file and a similarly
+                    named configuration fragment file
+                    <filename>test.cfg</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Add the Feature File to <filename>SRC_URI</filename>:</emphasis>
+                    Add the <filename>.scc</filename> file to the
+                    recipe's <filename>SRC_URI</filename> statement:
+                    <literallayout class='monospaced'>
+     SRC_URI_append = " file://test.scc"
+                    </literallayout>
+                    The leading space before the path is important as the
+                    path is appended to the existing path.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Specify the Feature as a Kernel Feature:</emphasis>
+                    Use the <filename>KERNEL_FEATURES</filename> statement
+                    to specify the feature as a kernel feature:
+                    <literallayout class='monospaced'>
+     KERNEL_FEATURES_append = " test.scc"
+                    </literallayout>
+                    The OpenEmbedded build system processes the kernel feature
+                    when it builds the kernel.
+                    <note>
+                        If other features are contained below "test.scc",
+                        then their directories are relative to the directory
+                        containing the <filename>test.scc</filename> file.
+                    </note>
+                    </para></listitem>
+            </orderedlist>
+        </para>
+    </section>
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst
index 5b6ebef..04cb117 100644
--- a/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 ************************
 Advanced Kernel Concepts
diff --git a/poky/documentation/kernel-dev/kernel-dev-concepts-appx.xml b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.xml
new file mode 100644
index 0000000..bf0c525
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-concepts-appx.xml
@@ -0,0 +1,622 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<appendix id='kernel-dev-concepts-appx'>
+<title>Advanced Kernel Concepts</title>
+
+    <section id='kernel-big-picture'>
+        <title>Yocto Project Kernel Development and Maintenance</title>
+
+        <para>
+            Kernels available through the Yocto Project (Yocto Linux kernels),
+            like other kernels, are based off the Linux kernel releases from
+            <ulink url='http://www.kernel.org'></ulink>.
+            At the beginning of a major Linux kernel development cycle, the
+            Yocto Project team chooses a Linux kernel based on factors such as
+            release timing, the anticipated release timing of final upstream
+            <filename>kernel.org</filename> versions, and Yocto Project
+            feature requirements.
+            Typically, the Linux kernel chosen is in the final stages of
+            development by the Linux community.
+            In other words, the Linux kernel is in the release candidate
+            or "rc" phase and has yet to reach final release.
+            But, by being in the final stages of external development, the
+            team knows that the <filename>kernel.org</filename> final release
+            will clearly be within the early stages of the Yocto Project
+            development window.
+        </para>
+
+        <para>
+            This balance allows the Yocto Project team to deliver the most
+            up-to-date Yocto Linux kernel possible, while still ensuring that
+            the team has a stable official release for the baseline Linux
+            kernel version.
+        </para>
+
+        <para>
+            As implied earlier, the ultimate source for Yocto Linux kernels
+            are released kernels from <filename>kernel.org</filename>.
+            In addition to a foundational kernel from
+            <filename>kernel.org</filename>, the available Yocto Linux kernels
+            contain a mix of important new mainline developments, non-mainline
+            developments (when no alternative exists), Board Support Package
+            (BSP) developments, and custom features.
+            These additions result in a commercially released Yocto
+            Project Linux kernel that caters to specific embedded designer
+            needs for targeted hardware.
+        </para>
+
+        <para>
+            You can find a web interface to the Yocto Linux kernels in the
+            <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+            at
+            <ulink url='&YOCTO_GIT_URL;'></ulink>.
+            If you look at the interface, you will see to the left a
+            grouping of Git repositories titled "Yocto Linux Kernel".
+            Within this group, you will find several Linux Yocto kernels
+            developed and included with Yocto Project releases:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.1</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.0.
+                    This kernel is based on the Linux 4.1 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.4</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.1.
+                    This kernel is based on the Linux 4.4 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.6</filename>:</emphasis>
+                    A temporary kernel that is not tied to any Yocto Project
+                    release.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.8</filename>:</emphasis>
+                    The stable yocto Project kernel to use with the Yocto
+                    Project Release 2.2.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.9</filename>:</emphasis>
+                    The stable Yocto Project kernel to use with the Yocto
+                    Project Release 2.3.
+                    This kernel is based on the Linux 4.9 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.10</filename>:</emphasis>
+                    The default stable Yocto Project kernel to use with the
+                    Yocto Project Release 2.3.
+                    This kernel is based on the Linux 4.10 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-4.12</filename>:</emphasis>
+                    The default stable Yocto Project kernel to use with the
+                    Yocto Project Release 2.4.
+                    This kernel is based on the Linux 4.12 released kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>yocto-kernel-cache</filename>:</emphasis>
+                    The <filename>linux-yocto-cache</filename> contains
+                    patches and configurations for the linux-yocto kernel
+                    tree.
+                    This repository is useful when working on the linux-yocto
+                    kernel.
+                    For more information on this "Advanced Kernel Metadata",
+                    see the
+                    "<link linkend='kernel-dev-advanced'>Working With Advanced Metadata (<filename>yocto-kernel-cache</filename>)</link>"
+                    Chapter.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto-dev</filename>:</emphasis>
+                    A development kernel based on the latest upstream release
+                    candidate available.
+                    </para></listitem>
+            </itemizedlist>
+            <note><title>Notes</title>
+                Long Term Support Initiative (LTSI) for Yocto Linux
+                kernels is as follows:
+                <itemizedlist>
+                    <listitem><para>
+                        For Yocto Project releases 1.7, 1.8, and 2.0,
+                        the LTSI kernel is
+                        <filename>linux-yocto-3.14</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        For Yocto Project releases 2.1, 2.2, and 2.3,
+                        the LTSI kernel is <filename>linux-yocto-4.1</filename>.
+                        </para></listitem>
+                    <listitem><para>
+                        For Yocto Project release 2.4, the LTSI kernel is
+                        <filename>linux-yocto-4.9</filename>
+                        </para></listitem>
+                    <listitem><para>
+                        <filename>linux-yocto-4.4</filename> is an LTS
+                        kernel.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </para>
+
+        <para>
+            Once a Yocto Linux kernel is officially released, the Yocto
+            Project team goes into their next development cycle, or upward
+            revision (uprev) cycle, while still continuing maintenance on the
+            released kernel.
+            It is important to note that the most sustainable and stable way
+            to include feature development upstream is through a kernel uprev
+            process.
+            Back-porting hundreds of individual fixes and minor features from
+            various kernel versions is not sustainable and can easily
+            compromise quality.
+        </para>
+
+        <para>
+            During the uprev cycle, the Yocto Project team uses an ongoing
+            analysis of Linux kernel development, BSP support, and release
+            timing to select the best possible <filename>kernel.org</filename>
+            Linux kernel version on which to base subsequent Yocto Linux
+            kernel development.
+            The team continually monitors Linux community kernel development
+            to look for significant features of interest.
+            The team does consider back-porting large features if they have a
+            significant advantage.
+            User or community demand can also trigger a back-port or creation
+            of new functionality in the Yocto Project baseline kernel during
+            the uprev cycle.
+        </para>
+
+        <para>
+            Generally speaking, every new Linux kernel both adds features and
+            introduces new bugs.
+            These consequences are the basic properties of upstream
+            Linux kernel development and are managed by the Yocto Project
+            team's Yocto Linux kernel development strategy.
+            It is the Yocto Project team's policy to not back-port minor
+            features to the released Yocto Linux kernel.
+            They only consider back-porting significant technological
+            jumps &dash; and, that is done after a complete gap analysis.
+            The reason for this policy is that back-porting any small to
+            medium sized change from an evolving Linux kernel can easily
+            create mismatches, incompatibilities and very subtle errors.
+        </para>
+
+        <para>
+            The policies described in this section result in both a stable
+            and a cutting edge Yocto Linux kernel that mixes forward ports of
+            existing Linux kernel features and significant and critical new
+            functionality.
+            Forward porting Linux kernel functionality into the Yocto Linux
+            kernels available through the Yocto Project can be thought of as
+            a "micro uprev."
+            The many "micro uprevs" produce a Yocto Linux kernel version with
+            a mix of important new mainline, non-mainline, BSP developments
+            and feature integrations.
+            This Yocto Linux kernel gives insight into new features and
+            allows focused amounts of testing to be done on the kernel,
+            which prevents surprises when selecting the next major uprev.
+            The quality of these cutting edge Yocto Linux kernels is evolving
+            and the kernels are used in leading edge feature and BSP
+            development.
+        </para>
+    </section>
+
+    <section id='yocto-linux-kernel-architecture-and-branching-strategies'>
+        <title>Yocto Linux Kernel Architecture and Branching Strategies</title>
+
+        <para>
+            As mentioned earlier, a key goal of the Yocto Project is
+            to present the developer with a kernel that has a clear and
+            continuous history that is visible to the user.
+            The architecture and mechanisms, in particular the branching
+            strategies, used achieve that goal in a manner similar to
+            upstream Linux kernel development in
+            <filename>kernel.org</filename>.
+        </para>
+
+        <para>
+            You can think of a Yocto Linux kernel as consisting of a
+            baseline Linux kernel with added features logically structured
+            on top of the baseline.
+            The features are tagged and organized by way of a branching
+            strategy implemented by the Yocto Project team using the
+            Source Code Manager (SCM) Git.
+            <note><title>Notes</title>
+                <itemizedlist>
+                    <listitem><para>
+                        Git is the obvious SCM for meeting the Yocto Linux
+                        kernel organizational and structural goals described
+                        in this section.
+                        Not only is Git the SCM for Linux kernel development in
+                        <filename>kernel.org</filename> but, Git continues to
+                         grow in popularity and supports many different work
+                         flows, front-ends and management techniques.
+                        </para></listitem>
+                    <listitem><para>
+                        You can find documentation on Git at
+                        <ulink url='http://git-scm.com/documentation'></ulink>.
+                        You can also get an introduction to Git as it
+                        applies to the Yocto Project in the
+                        "<ulink url='&YOCTO_DOCS_OM_URL;#git'>Git</ulink>"
+                        section in the Yocto Project Overview and Concepts
+                        Manual.
+                        The latter reference provides an overview of
+                        Git and presents a minimal set of Git commands
+                        that allows you to be functional using Git.
+                        You can use as much, or as little, of what Git
+                        has to offer to accomplish what you need for your
+                        project.
+                        You do not have to be a "Git Expert" in order to
+                        use it with the Yocto Project.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </para>
+
+        <para>
+            Using Git's tagging and branching features, the Yocto Project
+            team creates kernel branches at points where functionality is
+            no longer shared and thus, needs to be isolated.
+            For example, board-specific incompatibilities would require
+            different functionality and would require a branch to
+            separate the features.
+            Likewise, for specific kernel features, the same branching
+            strategy is used.
+        </para>
+
+        <para>
+            This "tree-like" architecture results in a structure that has
+            features organized to be specific for particular functionality,
+            single kernel types, or a subset of kernel types.
+            Thus, the user has the ability to see the added features and the
+            commits that make up those features.
+            In addition to being able to see added features, the user
+            can also view the history of what made up the baseline
+            Linux kernel.
+        </para>
+
+        <para>
+            Another consequence of this strategy results in not having to
+            store the same feature twice internally in the tree.
+            Rather, the kernel team stores the unique differences required
+            to apply the feature onto the kernel type in question.
+            <note>
+                The Yocto Project team strives to place features in the tree
+                such that features can be shared by all boards and kernel
+                types where possible.
+                However, during development cycles or when large features
+                are merged, the team cannot always follow this practice.
+                In those cases, the team uses isolated branches to merge
+                features.
+            </note>
+        </para>
+
+        <para>
+            BSP-specific code additions are handled in a similar manner to
+            kernel-specific additions.
+            Some BSPs only make sense given certain kernel types.
+            So, for these types, the team creates branches off the end
+            of that kernel type for all of the BSPs that are supported on
+            that kernel type.
+            From the perspective of the tools that create the BSP branch,
+            the BSP is really no different than a feature.
+            Consequently, the same branching strategy applies to BSPs as
+            it does to kernel features.
+            So again, rather than store the BSP twice, the team only
+            stores the unique differences for the BSP across the supported
+            multiple kernels.
+        </para>
+
+        <para>
+            While this strategy can result in a tree with a significant number
+            of branches, it is important to realize that from the developer's
+            point of view, there is a linear path that travels from the
+            baseline <filename>kernel.org</filename>, through a select
+            group of features and ends with their BSP-specific commits.
+            In other words, the divisions of the kernel are transparent and
+            are not relevant to the developer on a day-to-day basis.
+            From the developer's perspective, this path is the "master" branch
+            in Git terms.
+            The developer does not need to be aware of the existence of any
+            other branches at all.
+            Of course, value exists in the having these branches in the tree,
+            should a person decide to explore them.
+            For example, a comparison between two BSPs at either the commit
+            level or at the line-by-line code <filename>diff</filename> level
+            is now a trivial operation.
+        </para>
+
+        <para>
+            The following illustration shows the conceptual Yocto
+            Linux kernel.
+            <imagedata fileref="figures/kernel-architecture-overview.png" width="6in" depth="7in" align="center" scale="100" />
+        </para>
+
+        <para>
+            In the illustration, the "Kernel.org Branch Point" marks the
+            specific spot (or Linux kernel release) from which the
+            Yocto Linux kernel is created.
+            From this point forward in the tree, features and differences
+            are organized and tagged.
+        </para>
+
+        <para>
+            The "Yocto Project Baseline Kernel" contains functionality that
+            is common to every kernel type and BSP that is organized
+            further along in the tree.
+            Placing these common features in the tree this way means
+            features do not have to be duplicated along individual
+            branches of the tree structure.
+        </para>
+
+        <para>
+            From the "Yocto Project Baseline Kernel", branch points represent
+            specific functionality for individual Board Support Packages
+            (BSPs) as well as real-time kernels.
+            The illustration represents this through three BSP-specific
+            branches and a real-time kernel branch.
+            Each branch represents some unique functionality for the BSP
+            or for a real-time Yocto Linux kernel.
+        </para>
+
+        <para>
+            In this example structure, the "Real-time (rt) Kernel" branch has
+            common features for all real-time Yocto Linux kernels and
+            contains more branches for individual BSP-specific real-time
+            kernels.
+            The illustration shows three branches as an example.
+            Each branch points the way to specific, unique features for a
+            respective real-time kernel as they apply to a given BSP.
+        </para>
+
+        <para>
+            The resulting tree structure presents a clear path of markers
+            (or branches) to the developer that, for all practical
+            purposes, is the Yocto Linux kernel needed for any given set of
+            requirements.
+            <note>
+                Keep in mind the figure does not take into account all the
+                supported Yocto Linux kernels, but rather shows a single
+                generic kernel just for conceptual purposes.
+                Also keep in mind that this structure represents the Yocto
+                Project
+                <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>
+                that are either pulled from during the build or established
+                on the host development system prior to the build by either
+                cloning a particular kernel's Git repository or by
+                downloading and unpacking a tarball.
+            </note>
+        </para>
+
+        <para>
+            Working with the kernel as a structured tree follows recognized
+            community best practices.
+            In particular, the kernel as shipped with the product, should be
+            considered an "upstream source" and viewed as a series of
+            historical and documented modifications (commits).
+            These modifications represent the development and stabilization
+            done by the Yocto Project kernel development team.
+        </para>
+
+        <para>
+            Because commits only change at significant release points in the
+            product life cycle, developers can work on a branch created
+            from the last relevant commit in the shipped Yocto Project Linux
+            kernel.
+            As mentioned previously, the structure is transparent to the
+            developer because the kernel tree is left in this state after
+            cloning and building the kernel.
+        </para>
+    </section>
+
+    <section id='kernel-build-file-hierarchy'>
+        <title>Kernel Build File Hierarchy</title>
+
+        <para>
+            Upstream storage of all the available kernel source code is
+            one thing, while representing and using the code on your host
+            development system is another.
+            Conceptually, you can think of the kernel source repositories
+            as all the source files necessary for all the supported
+            Yocto Linux kernels.
+            As a developer, you are just interested in the source files
+            for the kernel on which you are working.
+            And, furthermore, you need them available on your host system.
+        </para>
+
+        <para>
+            Kernel source code is available on your host system several
+            different ways:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis>Files Accessed While using <filename>devtool</filename>:</emphasis>
+                    <filename>devtool</filename>, which is available with the
+                    Yocto Project, is the preferred method by which to
+                    modify the kernel.
+                    See the
+                    "<link linkend='kernel-modification-workflow'>Kernel Modification Workflow</link>"
+                    section.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Cloned Repository:</emphasis>
+                    If you are working in the kernel all the time, you probably
+                    would want to set up your own local Git repository of the
+                    Yocto Linux kernel tree.
+                    For information on how to clone a Yocto Linux kernel
+                    Git repository, see the
+                    "<link linkend='preparing-the-build-host-to-work-on-the-kernel'>Preparing the Build Host to Work on the Kernel</link>"
+                    section.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Temporary Source Files from a Build:</emphasis>
+                    If you just need to make some patches to the kernel using
+                    a traditional BitBake workflow (i.e. not using the
+                    <filename>devtool</filename>), you can access temporary
+                    kernel source files that were extracted and used during
+                    a kernel build.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+
+        <para>
+            The temporary kernel source files resulting from a build using
+            BitBake have a particular hierarchy.
+            When you build the kernel on your development system, all files
+            needed for the build are taken from the source repositories
+            pointed to by the
+            <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+            variable and gathered in a temporary work area where they are
+            subsequently used to create the unique kernel.
+            Thus, in a sense, the process constructs a local source tree
+            specific to your kernel from which to generate the new kernel
+            image.
+        </para>
+
+        <para>
+            The following figure shows the temporary file structure
+            created on your host system when you build the kernel using
+            Bitbake.
+            This
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+            contains all the source files used during the build.
+            <imagedata fileref="figures/kernel-overview-2-generic.png"
+                width="6in" depth="5in" align="center" scale="100" />
+        </para>
+
+        <para>
+            Again, for additional information on the Yocto Project kernel's
+            architecture and its branching strategy, see the
+            "<link linkend='yocto-linux-kernel-architecture-and-branching-strategies'>Yocto Linux Kernel Architecture and Branching Strategies</link>"
+            section.
+            You can also reference the
+            "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+            and
+            "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+            sections for detailed example that modifies the kernel.
+        </para>
+    </section>
+
+    <section id='determining-hardware-and-non-hardware-features-for-the-kernel-configuration-audit-phase'>
+        <title>Determining Hardware and Non-Hardware Features for the Kernel Configuration Audit Phase</title>
+
+        <para>
+            This section describes part of the kernel configuration audit
+            phase that most developers can ignore.
+            For general information on kernel configuration including
+            <filename>menuconfig</filename>, <filename>defconfig</filename>
+            files, and configuration fragments, see the
+            "<link linkend='configuring-the-kernel'>Configuring the Kernel</link>"
+            section.
+        </para>
+
+        <para>
+            During this part of the audit phase, the contents of the final
+            <filename>.config</filename> file are compared against the
+            fragments specified by the system.
+            These fragments can be system fragments, distro fragments,
+            or user-specified configuration elements.
+            Regardless of their origin, the OpenEmbedded build system
+            warns the user if a specific option is not included in the
+            final kernel configuration.
+        </para>
+
+        <para>
+            By default, in order to not overwhelm the user with
+            configuration warnings, the system only reports missing
+            "hardware" options as they could result in a boot
+            failure or indicate that important hardware is not available.
+        </para>
+
+        <para>
+            To determine whether or not a given option is "hardware" or
+            "non-hardware", the kernel Metadata in
+            <filename>yocto-kernel-cache</filename> contains files that
+            classify individual or groups of options as either hardware
+            or non-hardware.
+            To better show this, consider a situation where the
+            <filename>yocto-kernel-cache</filename> contains the following
+            files:
+            <literallayout class='monospaced'>
+     yocto-kernel-cache/features/drm-psb/hardware.cfg
+     yocto-kernel-cache/features/kgdb/hardware.cfg
+     yocto-kernel-cache/ktypes/base/hardware.cfg
+     yocto-kernel-cache/bsp/mti-malta32/hardware.cfg
+     yocto-kernel-cache/bsp/qemu-ppc32/hardware.cfg
+     yocto-kernel-cache/bsp/qemuarma9/hardware.cfg
+     yocto-kernel-cache/bsp/mti-malta64/hardware.cfg
+     yocto-kernel-cache/bsp/arm-versatile-926ejs/hardware.cfg
+     yocto-kernel-cache/bsp/common-pc/hardware.cfg
+     yocto-kernel-cache/bsp/common-pc-64/hardware.cfg
+     yocto-kernel-cache/features/rfkill/non-hardware.cfg
+     yocto-kernel-cache/ktypes/base/non-hardware.cfg
+     yocto-kernel-cache/features/aufs/non-hardware.kcf
+     yocto-kernel-cache/features/ocf/non-hardware.kcf
+     yocto-kernel-cache/ktypes/base/non-hardware.kcf
+     yocto-kernel-cache/ktypes/base/hardware.kcf
+     yocto-kernel-cache/bsp/qemu-ppc32/hardware.kcf
+            </literallayout>
+            The following list provides explanations for the various
+            files:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>hardware.kcf</filename>:
+                    Specifies a list of kernel Kconfig files that contain
+                    hardware options only.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>non-hardware.kcf</filename>:
+                    Specifies a list of kernel Kconfig files that contain
+                    non-hardware options only.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>hardware.cfg</filename>:
+                    Specifies a list of kernel <filename>CONFIG_</filename>
+                    options that are hardware, regardless of whether or not
+                    they are within a Kconfig file specified by a hardware
+                    or non-hardware Kconfig file (i.e.
+                    <filename>hardware.kcf</filename> or
+                    <filename>non-hardware.kcf</filename>).
+                    </para></listitem>
+                <listitem><para>
+                    <filename>non-hardware.cfg</filename>:
+                    Specifies a list of kernel <filename>CONFIG_</filename>
+                    options that are not hardware, regardless of whether or
+                    not they are within a Kconfig file specified by a
+                    hardware or non-hardware Kconfig file (i.e.
+                    <filename>hardware.kcf</filename> or
+                    <filename>non-hardware.kcf</filename>).
+                    </para></listitem>
+            </itemizedlist>
+            Here is a specific example using the
+            <filename>kernel-cache/bsp/mti-malta32/hardware.cfg</filename>:
+            <literallayout class='monospaced'>
+     CONFIG_SERIAL_8250
+     CONFIG_SERIAL_8250_CONSOLE
+     CONFIG_SERIAL_8250_NR_UARTS
+     CONFIG_SERIAL_8250_PCI
+     CONFIG_SERIAL_CORE
+     CONFIG_SERIAL_CORE_CONSOLE
+     CONFIG_VGA_ARB
+            </literallayout>
+            The kernel configuration audit automatically detects these
+            files (hence the names must be exactly the ones discussed here),
+            and uses them as inputs when generating warnings about the
+            final <filename>.config</filename> file.
+        </para>
+
+        <para>
+            A user-specified kernel Metadata repository, or recipe space
+            feature, can use these same files to classify options that are
+            found within its <filename>.cfg</filename> files as hardware
+            or non-hardware, to prevent the OpenEmbedded build system from
+            producing an error or warning when an option is not in the
+            final <filename>.config</filename> file.
+        </para>
+    </section>
+</appendix>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-customization.xsl b/poky/documentation/kernel-dev/kernel-dev-customization.xsl
new file mode 100644
index 0000000..88bf7c6
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-customization.xsl
@@ -0,0 +1,28 @@
+<?xml version='1.0'?>
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="http://www.w3.org/1999/xhtml" xmlns:fo="http://www.w3.org/1999/XSL/Format" version="1.0">
+
+  <xsl:import href="http://downloads.yoctoproject.org/mirror/docbook-mirror/docbook-xsl-1.76.1/xhtml/docbook.xsl" />
+
+<!--
+
+  <xsl:import href="../template/1.76.1/docbook-xsl-1.76.1/xhtml/docbook.xsl" />
+
+  <xsl:import href="http://docbook.sourceforge.net/release/xsl/1.76.1/xhtml/docbook.xsl" />
+
+-->
+
+  <xsl:include href="../template/permalinks.xsl"/>
+  <xsl:include href="../template/section.title.xsl"/>
+  <xsl:include href="../template/component.title.xsl"/>
+  <xsl:include href="../template/division.title.xsl"/>
+  <xsl:include href="../template/formal.object.heading.xsl"/>
+
+  <xsl:param name="html.stylesheet" select="'kernel-dev-style.css'" />
+  <xsl:param name="chapter.autolabel" select="1" />
+  <xsl:param name="appendix.autolabel">A</xsl:param>
+  <xsl:param name="section.autolabel" select="1" />
+  <xsl:param name="section.label.includes.component.label" select="1" />
+
+</xsl:stylesheet>
diff --git a/poky/documentation/kernel-dev/kernel-dev-faq.rst b/poky/documentation/kernel-dev/kernel-dev-faq.rst
index 70bf4a2..b5e6a84 100644
--- a/poky/documentation/kernel-dev/kernel-dev-faq.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-faq.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 **********************
 Kernel Development FAQ
diff --git a/poky/documentation/kernel-dev/kernel-dev-faq.xml b/poky/documentation/kernel-dev/kernel-dev-faq.xml
new file mode 100644
index 0000000..d76f0a4
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-faq.xml
@@ -0,0 +1,143 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<appendix id='kernel-dev-faq'>
+<title>Kernel Development FAQ</title>
+
+<section id='kernel-dev-faq-section'>
+    <title>Common Questions and Solutions</title>
+
+    <para>
+        The following lists some solutions for common questions.
+
+
+        <qandaset>
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I use my own Linux kernel <filename>.config</filename>
+                        file?
+                    </para>
+                </question>
+                <answer>
+            <para>
+                        Refer to the "<link linkend='changing-the-configuration'>Changing the Configuration</link>"
+                        section for information.
+                    </para>
+                </answer>
+            </qandaentry>
+
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I create configuration fragments?
+                    </para>
+                </question>
+                <answer>
+                    <para>
+                        Refer to the
+                        "<link linkend='creating-config-fragments'>Creating Configuration Fragments</link>"
+                        section for information.
+                    </para>
+                </answer>
+            </qandaentry>
+
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I use my own Linux kernel sources?
+                    </para>
+                </question>
+                <answer>
+                    <para>
+                        Refer to the "<link linkend='working-with-your-own-sources'>Working With Your Own Sources</link>"
+                        section for information.
+                    </para>
+                </answer>
+            </qandaentry>
+
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I install/not-install the kernel image on the rootfs?
+                    </para>
+                </question>
+                <answer>
+                    <para>
+                        The kernel image (e.g. <filename>vmlinuz</filename>) is provided
+                        by the <filename>kernel-image</filename> package.
+                        Image recipes depend on <filename>kernel-base</filename>.
+                        To specify whether or not the kernel
+                        image is installed in the generated root filesystem, override
+                        <filename>RDEPENDS_kernel-base</filename> to include or not
+                        include "kernel-image".</para>
+                        <para>See the
+                        "<ulink url='&YOCTO_DOCS_DEV_URL;#using-bbappend-files'>Using .bbappend Files in Your Layer</ulink>"
+                        section in the Yocto Project Development Tasks Manual
+                        for information on how to use an append file to
+                        override metadata.
+                    </para>
+                </answer>
+            </qandaentry>
+
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I install a specific kernel module?
+                    </para>
+                </question>
+                <answer>
+                    <para>
+                        Linux kernel modules are packaged individually.
+                        To ensure a specific kernel module is included in an image,
+                        include it in the appropriate machine
+                        <ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>
+                        variable.</para>
+                        <para>These other variables are useful for installing specific
+                        modules:
+                        <literallayout class='monospaced'>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RDEPENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RDEPENDS</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS'><filename>MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RDEPENDS'><filename>MACHINE_EXTRA_RDEPENDS</filename></ulink>
+     <ulink url='&YOCTO_DOCS_REF_URL;#var-MACHINE_EXTRA_RRECOMMENDS'><filename>MACHINE_EXTRA_RRECOMMENDS</filename></ulink>
+                        </literallayout>
+                        For example, set the following in the <filename>qemux86.conf</filename>
+                        file to include the <filename>ab123</filename> kernel modules
+                        with images built for the <filename>qemux86</filename> machine:
+                        <literallayout class='monospaced'>
+     MACHINE_EXTRA_RRECOMMENDS += "kernel-module-ab123"
+                        </literallayout>
+                        For more information, see the
+                        "<link linkend='incorporating-out-of-tree-modules'>Incorporating Out-of-Tree Modules</link>"
+                        section.
+                    </para>
+                </answer>
+            </qandaentry>
+
+            <qandaentry>
+                <question>
+                    <para>
+                        How do I change the Linux kernel command line?
+                   </para>
+                </question>
+                <answer>
+                    <para>
+                        The Linux kernel command line is typically specified in
+                        the machine config using the <filename>APPEND</filename> variable.
+                For example, you can add some helpful debug information doing
+                        the following:
+                        <literallayout class='monospaced'>
+     APPEND += "printk.time=y initcall_debug debug"
+                        </literallayout>
+                    </para>
+                </answer>
+            </qandaentry>
+        </qandaset>
+    </para>
+</section>
+</appendix>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-intro.rst b/poky/documentation/kernel-dev/kernel-dev-intro.rst
index 447cddb..21d43d5 100644
--- a/poky/documentation/kernel-dev/kernel-dev-intro.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-intro.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 ************
 Introduction
diff --git a/poky/documentation/kernel-dev/kernel-dev-intro.xml b/poky/documentation/kernel-dev/kernel-dev-intro.xml
new file mode 100644
index 0000000..7c1ea0e
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-intro.xml
@@ -0,0 +1,260 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='kernel-dev-intro'>
+<title>Introduction</title>
+
+<section id='kernel-dev-overview'>
+    <title>Overview</title>
+
+    <para>
+        Regardless of how you intend to make use of the Yocto Project,
+        chances are you will work with the Linux kernel.
+        This manual describes how to set up your build host to support
+        kernel development, introduces the kernel development process,
+        provides background information on the Yocto Linux kernel
+        <ulink url='&YOCTO_DOCS_REF_URL;#metadata'>Metadata</ulink>,
+        describes common tasks you can perform using the kernel tools,
+        shows you how to use the kernel Metadata needed to work with
+        the kernel inside the Yocto Project, and provides insight into how
+        the Yocto Project team develops and maintains Yocto Linux kernel
+        Git repositories and Metadata.
+   </para>
+
+   <para>
+        Each Yocto Project release has a set of Yocto Linux kernel recipes,
+        whose Git repositories you can view in the Yocto
+        <ulink url='&YOCTO_GIT_URL;'>Source Repositories</ulink> under
+        the "Yocto Linux Kernel" heading.
+        New recipes for the release track the latest Linux kernel
+        upstream developments from
+        <ulink url='http://www.kernel.org'></ulink> and introduce
+        newly-supported platforms.
+        Previous recipes in the release are refreshed and supported for at
+        least one additional Yocto Project release.
+        As they align, these previous releases are updated to include the
+        latest from the Long Term Support Initiative (LTSI) project.
+        You can learn more about Yocto Linux kernels and LTSI in the
+        "<link linkend='kernel-big-picture'>Yocto Project Kernel Development and Maintenance</link>"
+        section.
+    </para>
+
+    <para>
+        Also included is a Yocto Linux kernel development recipe
+        (<filename>linux-yocto-dev.bb</filename>) should you want to work
+        with the very latest in upstream Yocto Linux kernel development and
+        kernel Metadata development.
+        <note>
+            For more on Yocto Linux kernels, see the
+            "<link linkend='kernel-big-picture'>Yocto Project Kernel Development and Maintenance</link>
+            section.
+        </note>
+    </para>
+
+    <para>
+        The Yocto Project also provides a powerful set of kernel
+        tools for managing Yocto Linux kernel sources and configuration data.
+        You can use these tools to make a single configuration change,
+        apply multiple patches, or work with your own kernel sources.
+    </para>
+
+    <para>
+        In particular, the kernel tools allow you to generate configuration
+        fragments that specify only what you must, and nothing more.
+        Configuration fragments only need to contain the highest level
+        visible <filename>CONFIG</filename> options as presented by the
+        Yocto Linux kernel <filename>menuconfig</filename> system.
+        Contrast this against a complete Yocto Linux kernel
+        <filename>.config</filename> file, which includes all the automatically
+        selected <filename>CONFIG</filename> options.
+        This efficiency reduces your maintenance effort and allows you
+        to further separate your configuration in ways that make sense for
+        your project.
+        A common split separates policy and hardware.
+        For example, all your kernels might support the
+        <filename>proc</filename> and <filename>sys</filename> filesystems,
+        but only specific boards require sound, USB, or specific drivers.
+        Specifying these configurations individually allows you to aggregate
+        them together as needed, but maintains them in only one place.
+        Similar logic applies to separating source changes.
+    </para>
+
+    <para>
+        If you do not maintain your own kernel sources and need to make
+        only minimal changes to the sources, the released recipes provide a
+        vetted base upon which to layer your changes.
+        Doing so allows you to benefit from the continual kernel
+        integration and testing performed during development of the
+        Yocto Project.
+    </para>
+
+    <para>
+        If, instead, you have a very specific Linux kernel source tree
+        and are unable to align with one of the official Yocto Linux kernel
+        recipes, an alternative exists by which you can use the Yocto
+        Project Linux kernel tools with your own kernel sources.
+    </para>
+
+    <para>
+        The remainder of this manual provides instructions for completing
+        specific Linux kernel development tasks.
+        These instructions assume you are comfortable working with
+        <ulink url='http://openembedded.org/wiki/Bitbake'>BitBake</ulink>
+        recipes and basic open-source development tools.
+        Understanding these concepts will facilitate the process of working
+        with the kernel recipes.
+        If you find you need some additional background, please be sure to
+        review and understand the following documentation:
+        <itemizedlist>
+            <listitem><para>
+                <ulink url='&YOCTO_DOCS_BRIEF_URL;'>Yocto Project Quick Build</ulink>
+                document.
+                </para></listitem>
+            <listitem><para>
+                <ulink url='&YOCTO_DOCS_OM_URL;'>Yocto Project Overview and Concepts Manual</ulink>.
+                </para></listitem>
+            <listitem><para>
+                <ulink url='&YOCTO_DOCS_SDK_URL;#using-devtool-in-your-sdk-workflow'><filename>devtool</filename> workflow</ulink>
+                as described in the Yocto Project Application Development and
+                the Extensible Software Development Kit (eSDK) manual.
+                </para></listitem>
+            <listitem><para>
+                The
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>"
+                section in the Yocto Project Development Tasks Manual.
+                </para></listitem>
+            <listitem><para>
+                The
+                "<link linkend='kernel-modification-workflow'>Kernel Modification Workflow</link>"
+                section.
+                </para></listitem>
+        </itemizedlist>
+    </para>
+</section>
+
+<section id='kernel-modification-workflow'>
+    <title>Kernel Modification Workflow</title>
+
+    <para>
+        Kernel modification involves changing the Yocto Project kernel,
+        which could involve changing configuration options as well as adding
+        new kernel recipes.
+        Configuration changes can be added in the form of configuration
+        fragments, while recipe modification comes through the kernel's
+        <filename>recipes-kernel</filename> area in a kernel layer you create.
+    </para>
+
+    <para>
+        This section presents a high-level overview of the Yocto Project
+        kernel modification workflow.
+        The illustration and accompanying list provide general information
+        and references for further information.
+        <imagedata fileref="figures/kernel-dev-flow.png"
+            width="9in" depth="5in" align="center" scalefit="1" />
+    </para>
+
+    <para>
+        <orderedlist>
+            <listitem><para>
+
+
+                <emphasis>Set up Your Host Development System to Support
+                Development Using the Yocto Project</emphasis>:
+                See the
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#dev-manual-start'>Setting Up the Development Host to Use the Yocto Project</ulink>"
+                section in the Yocto Project Development Tasks Manual for
+                options on how to get a build host ready to use the Yocto
+                Project.
+                </para></listitem>
+            <listitem><para>
+                <emphasis>Set Up Your Host Development System for Kernel Development:</emphasis>
+                It is recommended that you use <filename>devtool</filename>
+                and an extensible SDK for kernel development.
+                Alternatively, you can use traditional kernel development
+                methods with the Yocto Project.
+                Either way, there are steps you need to take to get the
+                development environment ready.</para>
+
+                <para>Using <filename>devtool</filename> and the eSDK requires
+                that you have a clean build of the image and that you are
+                set up with the appropriate eSDK.
+                For more information, see the
+                "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using <filename>devtool</filename></link>"
+                section.</para>
+
+                <para>Using traditional kernel development requires that you
+                have the kernel source available in an isolated local Git
+                repository.
+                For more information, see the
+                "<link linkend='getting-ready-for-traditional-kernel-development'>Getting Ready for Traditional Kernel Development</link>"
+                section.
+                </para></listitem>
+            <listitem><para>
+                <emphasis>Make Changes to the Kernel Source Code if
+                applicable:</emphasis>
+                Modifying the kernel does not always mean directly
+                changing source files.
+                However, if you have to do this, you make the changes to the
+                files in the eSDK's Build Directory if you are using
+                <filename>devtool</filename>.
+                For more information, see the
+                "<link linkend='using-devtool-to-patch-the-kernel'>Using <filename>devtool</filename> to Patch the Kernel</link>"
+                section.</para>
+
+                <para>If you are using traditional kernel development, you
+                edit the source files in the kernel's local Git repository.
+                For more information, see the
+                "<link linkend='using-traditional-kernel-development-to-patch-the-kernel'>Using Traditional Kernel Development to Patch the Kernel</link>"
+                section.
+                </para></listitem>
+            <listitem><para>
+                <emphasis>Make Kernel Configuration Changes if
+                Applicable:</emphasis>
+                If your situation calls for changing the kernel's
+                configuration, you can use
+                <link linkend='using-menuconfig'><filename>menuconfig</filename></link>,
+                which allows you to interactively develop and test the
+                configuration changes you are making to the kernel.
+                Saving changes you make with <filename>menuconfig</filename>
+                updates the kernel's <filename>.config</filename> file.
+                <note><title>Warning</title>
+                    Try to resist the temptation to directly edit an
+                    existing <filename>.config</filename> file, which is
+                    found in the Build Directory among the source code
+                    used for the build.
+                    Doing so, can produce unexpected results when the
+                    OpenEmbedded build system regenerates the configuration
+                    file.
+                </note>
+                Once you are satisfied with the configuration
+                changes made using <filename>menuconfig</filename>
+                and you have saved them, you can directly compare the
+                resulting <filename>.config</filename> file against an
+                existing original and gather those changes into a
+                <link linkend='creating-config-fragments'>configuration fragment file</link>
+                to be referenced from within the kernel's
+                <filename>.bbappend</filename> file.</para>
+
+                <para>Additionally, if you are working in a BSP layer
+                and need to modify the BSP's kernel's configuration,
+                you can use <filename>menuconfig</filename>.
+                </para></listitem>
+            <listitem><para>
+                <emphasis>Rebuild the Kernel Image With Your Changes:</emphasis>
+                Rebuilding the kernel image applies your changes.
+                Depending on your target hardware, you can verify your changes
+                on actual hardware or perhaps QEMU.
+                </para></listitem>
+        </orderedlist>
+        The remainder of this developer's guide covers common tasks typically
+        used during kernel development, advanced Metadata usage, and Yocto Linux
+        kernel maintenance concepts.
+    </para>
+</section>
+
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-maint-appx.rst b/poky/documentation/kernel-dev/kernel-dev-maint-appx.rst
index 1788332..5514dac 100644
--- a/poky/documentation/kernel-dev/kernel-dev-maint-appx.rst
+++ b/poky/documentation/kernel-dev/kernel-dev-maint-appx.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 ******************
 Kernel Maintenance
diff --git a/poky/documentation/kernel-dev/kernel-dev-maint-appx.xml b/poky/documentation/kernel-dev/kernel-dev-maint-appx.xml
new file mode 100644
index 0000000..3d9c7c6
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-maint-appx.xml
@@ -0,0 +1,357 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<appendix id='kernel-dev-maint-appx'>
+<title>Kernel Maintenance</title>
+
+    <section id='tree-construction'>
+        <title>Tree Construction</title>
+
+        <para>
+            This section describes construction of the Yocto Project kernel
+            source repositories as accomplished by the Yocto Project team to
+            create Yocto Linux kernel repositories.
+            These kernel repositories are found under the heading "Yocto Linux
+            Kernel" at
+            <ulink url='&YOCTO_GIT_URL;'>&YOCTO_GIT_URL;</ulink>
+            and are shipped as part of a Yocto Project release.
+            The team creates these repositories by compiling and executing the
+            set of feature descriptions for every BSP and feature in the
+            product.
+            Those feature descriptions list all necessary patches,
+            configurations, branches, tags, and feature divisions found in a
+            Yocto Linux kernel.
+            Thus, the Yocto Project Linux kernel repository (or tree) and
+            accompanying Metadata in the
+            <filename>yocto-kernel-cache</filename> are built.
+        </para>
+
+        <para>
+            The existence of these repositories allow you to access and clone a
+            particular Yocto Project Linux kernel repository and use it to
+            build images based on their configurations and features.
+        </para>
+
+        <para>
+            You can find the files used to describe all the valid features and
+            BSPs in the Yocto Project Linux kernel in any clone of the Yocto
+            Project Linux kernel source repository and
+            <filename>yocto-kernel-cache</filename> Git trees.
+            For example, the following commands clone the Yocto Project
+            baseline Linux kernel that branches off
+            <filename>linux.org</filename> version 4.12 and the
+            <filename>yocto-kernel-cache</filename>, which contains stores of
+            kernel Metadata:
+            <literallayout class='monospaced'>
+     $ git clone git://git.yoctoproject.org/linux-yocto-4.12
+     $ git clone git://git.yoctoproject.org/linux-kernel-cache
+            </literallayout>
+            For more information on how to set up a local Git repository of
+            the Yocto Project Linux kernel files, see the
+            "<link linkend='preparing-the-build-host-to-work-on-the-kernel'>Preparing the Build Host to Work on the Kernel</link>"
+            section.
+        </para>
+
+        <para>
+            Once you have cloned the kernel Git repository and the
+            cache of Metadata on your local machine, you can discover the
+            branches that are available in the repository using the following
+            Git command:
+            <literallayout class='monospaced'>
+     $ git branch -a
+            </literallayout>
+            Checking out a branch allows you to work with a particular
+            Yocto Linux kernel.
+            For example, the following commands check out the
+            "standard/beagleboard" branch of the Yocto Linux kernel repository
+            and the "yocto-4.12" branch of the
+            <filename>yocto-kernel-cache</filename> repository:
+            <literallayout class='monospaced'>
+     $ cd ~/linux-yocto-4.12
+     $ git checkout -b my-kernel-4.12 remotes/origin/standard/beagleboard
+     $ cd ~/linux-kernel-cache
+     $ git checkout -b my-4.12-metadata remotes/origin/yocto-4.12
+            </literallayout>
+            <note>
+                Branches in the <filename>yocto-kernel-cache</filename>
+                repository correspond to Yocto Linux kernel versions
+                (e.g. "yocto-4.12", "yocto-4.10", "yocto-4.9", and so forth).
+            </note>
+            Once you have checked out and switched to appropriate branches,
+            you can see a snapshot of all the kernel source files used to
+            used to build that particular Yocto Linux kernel for a
+            particular board.
+        </para>
+
+        <para>
+            To see the features and configurations for a particular Yocto
+            Linux kernel, you need to examine the
+            <filename>yocto-kernel-cache</filename> Git repository.
+            As mentioned, branches in the
+            <filename>yocto-kernel-cache</filename> repository correspond to
+            Yocto Linux kernel versions (e.g. <filename>yocto-4.12</filename>).
+            Branches contain descriptions in the form of
+            <filename>.scc</filename> and <filename>.cfg</filename> files.
+        </para>
+
+        <para>
+            You should realize, however, that browsing your local
+            <filename>yocto-kernel-cache</filename> repository for feature
+            descriptions and patches is not an effective way to determine what
+            is in a particular kernel branch.
+            Instead, you should use Git directly to discover the changes in
+            a branch.
+            Using Git is an efficient and flexible way to inspect changes to
+            the kernel.
+            <note>
+                Ground up reconstruction of the complete kernel tree is an
+                action only taken by the Yocto Project team during an active
+                development cycle.
+                When you create a clone of the kernel Git repository, you are
+                simply making it efficiently available for building and
+                development.
+            </note>
+        </para>
+
+        <para>
+            The following steps describe what happens when the Yocto Project
+            Team constructs the Yocto Project kernel source Git repository
+            (or tree) found at
+            <ulink url='&YOCTO_GIT_URL;'></ulink> given the
+            introduction of a new top-level kernel feature or BSP.
+            The following actions effectively provide the Metadata
+            and create the tree that includes the new feature, patch, or BSP:
+            <orderedlist>
+                <listitem><para>
+                    <emphasis>Pass Feature to the OpenEmbedded Build System:</emphasis>
+                    A top-level kernel feature is passed to the kernel build
+                    subsystem.
+                    Normally, this feature is a BSP for a particular kernel
+                    type.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Locate Feature:</emphasis>
+                    The file that describes the top-level feature is located
+                    by searching these system directories:
+                    <itemizedlist>
+                        <listitem><para>
+                            The in-tree kernel-cache directories, which are
+                            located in the
+                            <ulink url='&YOCTO_GIT_URL;/cgit/cgit.cgi/yocto-kernel-cache/tree/bsp'><filename>yocto-kernel-cache</filename></ulink>
+                            repository organized under the "Yocto Linux Kernel"
+                            heading in the
+                            <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi'>Yocto Project Source Repositories</ulink>.
+                            </para></listitem>
+                        <listitem><para>
+                            Areas pointed to by <filename>SRC_URI</filename>
+                            statements found in kernel recipes
+                            </para></listitem>
+                    </itemizedlist>
+                    For a typical build, the target of the search is a
+                    feature description in an <filename>.scc</filename> file
+                    whose name follows this format (e.g.
+                    <filename>beaglebone-standard.scc</filename> and
+                    <filename>beaglebone-preempt-rt.scc</filename>):
+                    <literallayout class='monospaced'>
+     <replaceable>bsp_root_name</replaceable>-<replaceable>kernel_type</replaceable>.scc
+                    </literallayout>
+                </para></listitem>
+                <listitem><para>
+                    <emphasis>Expand Feature:</emphasis>
+                    Once located, the feature description is either expanded
+                    into a simple script of actions, or into an existing
+                    equivalent script that is already part of the shipped
+                    kernel.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Append Extra Features:</emphasis>
+                    Extra features are appended to the top-level feature
+                    description.
+                    These features can come from the
+                    <ulink url='&YOCTO_DOCS_REF_URL;#var-KERNEL_FEATURES'><filename>KERNEL_FEATURES</filename></ulink>
+                    variable in recipes.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Locate, Expand, and Append Each Feature:</emphasis>
+                    Each extra feature is located, expanded and appended to
+                    the script as described in step three.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Execute the Script:</emphasis>
+                    The script is executed to produce files
+                    <filename>.scc</filename> and <filename>.cfg</filename>
+                    files in appropriate directories of the
+                    <filename>yocto-kernel-cache</filename> repository.
+                    These files are descriptions of all the branches, tags,
+                    patches and configurations that need to be applied to the
+                    base Git repository to completely create the
+                    source (build) branch for the new BSP or feature.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Clone Base Repository:</emphasis>
+                    The base repository is cloned, and the actions
+                    listed in the <filename>yocto-kernel-cache</filename>
+                    directories are applied to the tree.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Perform Cleanup:</emphasis>
+                    The Git repositories are left with the desired branches
+                    checked out and any required branching, patching and
+                    tagging has been performed.
+                    </para></listitem>
+            </orderedlist>
+        </para>
+
+        <para>
+            The kernel tree and cache are ready for developer consumption to
+            be locally cloned, configured, and built into a Yocto Project
+            kernel specific to some target hardware.
+            <note><title>Notes</title>
+                <itemizedlist>
+                    <listitem><para>
+                        The generated <filename>yocto-kernel-cache</filename>
+                        repository adds to the kernel as shipped with the Yocto
+                        Project release.
+                        Any add-ons and configuration data are applied to the
+                        end of an existing branch.
+                        The full repository generation that is found in the
+                        official Yocto Project kernel repositories at
+                        <ulink url='&YOCTO_GIT_URL;'>http://git.yoctoproject.org</ulink>
+                        is the combination of all supported boards and
+                        configurations.
+                        </para></listitem>
+                    <listitem><para>
+                        The technique the Yocto Project team uses is flexible
+                        and allows for seamless blending of an immutable
+                        history with additional patches specific to a
+                        deployment.
+                        Any additions to the kernel become an integrated part
+                        of the branches.
+                        </para></listitem>
+                    <listitem><para>
+                        The full kernel tree that you see on
+                        <ulink url='&YOCTO_GIT_URL;'></ulink> is
+                        generated through repeating the above steps for all
+                        valid BSPs.
+                        The end result is a branched, clean history tree that
+                        makes up the kernel for a given release.
+                        You can see the script (<filename>kgit-scc</filename>)
+                        responsible for this in the
+                        <ulink url='&YOCTO_GIT_URL;/cgit.cgi/yocto-kernel-tools/tree/tools'><filename>yocto-kernel-tools</filename></ulink>
+                        repository.
+                        </para></listitem>
+                    <listitem><para>
+                        The steps used to construct the full kernel tree are
+                        the same steps that BitBake uses when it builds a
+                        kernel image.
+                        </para></listitem>
+                </itemizedlist>
+            </note>
+        </para>
+    </section>
+
+    <section id='build-strategy'>
+        <title>Build Strategy</title>
+
+        <para>
+            Once you have cloned a Yocto Linux kernel repository and the
+            cache repository (<filename>yocto-kernel-cache</filename>) onto
+            your development system, you can consider the compilation phase
+            of kernel development, which is building a kernel image.
+            Some prerequisites exist that are validated by the build process
+            before compilation starts:
+        </para>
+
+        <itemizedlist>
+            <listitem><para>
+                The
+                <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+                points to the kernel Git repository.
+                </para></listitem>
+            <listitem><para>
+                A BSP build branch with Metadata exists in the
+                <filename>yocto-kernel-cache</filename> repository.
+                The branch is based on the Yocto Linux kernel version and
+                has configurations and features grouped under the
+                <filename>yocto-kernel-cache/bsp</filename> directory.
+                For example, features and configurations for the
+                BeagleBone Board assuming a
+                <filename>linux-yocto_4.12</filename> kernel reside in the
+                following area of the <filename>yocto-kernel-cache</filename>
+                repository:
+                <literallayout class='monospaced'>
+     yocto-kernel-cache/bsp/beaglebone
+                </literallayout>
+                <note>
+                    In the previous example, the "yocto-4.12" branch is
+                    checked out in the <filename>yocto-kernel-cache</filename>
+                    repository.
+                </note>
+                </para></listitem>
+        </itemizedlist>
+
+        <para>
+            The OpenEmbedded build system makes sure these conditions exist
+            before attempting compilation.
+            Other means, however, do exist, such as as bootstrapping a BSP.
+        </para>
+
+        <para>
+            Before building a kernel, the build process verifies the tree
+            and configures the kernel by processing all of the
+            configuration "fragments" specified by feature descriptions
+            in the <filename>.scc</filename> files.
+            As the features are compiled, associated kernel configuration
+            fragments are noted and recorded in the series of directories
+            in their compilation order.
+            The fragments are migrated, pre-processed and passed to the
+            Linux Kernel Configuration subsystem (<filename>lkc</filename>) as
+            raw input in the form of a <filename>.config</filename> file.
+            The <filename>lkc</filename> uses its own internal dependency
+            constraints to do the final processing of that information and
+            generates the final <filename>.config</filename> file that is used
+            during compilation.
+        </para>
+
+        <para>
+            Using the board's architecture and other relevant values from
+            the board's template, kernel compilation is started and a kernel
+            image is produced.
+        </para>
+
+        <para>
+            The other thing that you notice once you configure a kernel is that
+            the build process generates a build tree that is separate from
+            your kernel's local Git source repository tree.
+            This build tree has a name that uses the following form, where
+            <filename>${MACHINE}</filename> is the metadata name of the
+            machine (BSP) and "kernel_type" is one of the Yocto Project
+            supported kernel types (e.g. "standard"):
+        <literallayout class='monospaced'>
+     linux-${MACHINE}-<replaceable>kernel_type</replaceable>-build
+        </literallayout>
+        </para>
+
+        <para>
+            The existing support in the <filename>kernel.org</filename> tree
+            achieves this default functionality.
+        </para>
+
+        <para>
+            This behavior means that all the generated files for a particular
+            machine or BSP are now in the build tree directory.
+            The files include the final <filename>.config</filename> file,
+            all the <filename>.o</filename> files, the <filename>.a</filename>
+            files, and so forth.
+            Since each machine or BSP has its own separate
+            <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
+            in its own separate branch of the Git repository, you can easily
+            switch between different builds.
+        </para>
+    </section>
+</appendix>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/poky/documentation/kernel-dev/kernel-dev-style.css b/poky/documentation/kernel-dev/kernel-dev-style.css
new file mode 100644
index 0000000..fc6fbb8
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev-style.css
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+     William Skaggs
+     Jakub Steiner
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+}
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+}
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+}
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+}
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diff --git a/poky/documentation/kernel-dev/kernel-dev.rst b/poky/documentation/kernel-dev/kernel-dev.rst
index 55b42ed..332e089 100644
--- a/poky/documentation/kernel-dev/kernel-dev.rst
+++ b/poky/documentation/kernel-dev/kernel-dev.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+.. SPDX-License-Identifier: CC-BY-2.0-UK
 
 =============================================
 Yocto Project Linux Kernel Development Manual
diff --git a/poky/documentation/kernel-dev/kernel-dev.xml b/poky/documentation/kernel-dev/kernel-dev.xml
new file mode 100755
index 0000000..887ff83
--- /dev/null
+++ b/poky/documentation/kernel-dev/kernel-dev.xml
@@ -0,0 +1,187 @@
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<book id='kernel-dev' lang='en'
+      xmlns:xi="http://www.w3.org/2003/XInclude"
+      xmlns="http://docbook.org/ns/docbook"
+      >
+    <bookinfo>
+
+        <mediaobject>
+            <imageobject>
+                <imagedata fileref='figures/kernel-dev-title.png'
+                    format='SVG'
+                    align='left' scalefit='1' width='100%'/>
+            </imageobject>
+        </mediaobject>
+
+        <title>
+		  Yocto Project Linux Kernel Development Manual
+		</title>
+
+        <authorgroup>
+            <author>
+                <affiliation>
+                    <orgname>&ORGNAME;</orgname>
+                </affiliation>
+                <email>&ORGEMAIL;</email>
+            </author>
+        </authorgroup>
+
+        <revhistory>
+            <revision>
+                <revnumber>1.4</revnumber>
+                <date>April 2013</date>
+                <revremark>The initial document released with the Yocto Project 1.4 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>1.5</revnumber>
+                <date>October 2013</date>
+                <revremark>Released with the Yocto Project 1.5 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>1.6</revnumber>
+                <date>April 2014</date>
+                <revremark>Released with the Yocto Project 1.6 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>1.7</revnumber>
+                <date>October 2014</date>
+                <revremark>Released with the Yocto Project 1.7 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>1.8</revnumber>
+                <date>April 2015</date>
+                <revremark>Released with the Yocto Project 1.8 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.0</revnumber>
+                <date>October 2015</date>
+                <revremark>Released with the Yocto Project 2.0 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.1</revnumber>
+                <date>April 2016</date>
+                <revremark>Released with the Yocto Project 2.1 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.2</revnumber>
+                <date>October 2016</date>
+                <revremark>Released with the Yocto Project 2.2 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.3</revnumber>
+                <date>May 2017</date>
+                <revremark>Released with the Yocto Project 2.3 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.4</revnumber>
+                <date>October 2017</date>
+                <revremark>Released with the Yocto Project 2.4 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.5</revnumber>
+                <date>May 2018</date>
+                <revremark>Released with the Yocto Project 2.5 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.6</revnumber>
+                <date>November 2018</date>
+                <revremark>Released with the Yocto Project 2.6 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>2.7</revnumber>
+                <date>May 2019</date>
+                <revremark>Released with the Yocto Project 2.7 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>3.0</revnumber>
+                <date>October 2019</date>
+                <revremark>Released with the Yocto Project 3.0 Release.</revremark>
+            </revision>
+            <revision>
+                <revnumber>3.1</revnumber>
+                <date>&REL_MONTH_YEAR;</date>
+                <revremark>Released with the Yocto Project 3.1 Release.</revremark>
+            </revision>
+        </revhistory>
+
+    <copyright>
+      <year>&COPYRIGHT_YEAR;</year>
+      <holder>Linux Foundation</holder>
+    </copyright>
+
+    <legalnotice>
+      <para>
+        Permission is granted to copy, distribute and/or modify this document under
+        the terms of the <ulink type="http" url="http://creativecommons.org/licenses/by-sa/2.0/uk/">Creative Commons Attribution-Share Alike 2.0 UK: England &amp; Wales</ulink> as published by Creative Commons.
+      </para>
+           <note><title>Manual Notes</title>
+               <itemizedlist>
+                   <listitem><para>
+                       This version of the
+                       <emphasis>Yocto Project Linux Kernel Development Manual</emphasis>
+                       is for the &YOCTO_DOC_VERSION; release of the
+                       Yocto Project.
+                       To be sure you have the latest version of the manual
+                       for this release, go to the
+                       <ulink url='&YOCTO_DOCS_URL;'>Yocto Project documentation page</ulink>
+                       and select the manual from that site.
+                       Manuals from the site are more up-to-date than manuals
+                       derived from the Yocto Project released TAR files.
+                       </para></listitem>
+                   <listitem><para>
+                       If you located this manual through a web search, the
+                       version of the manual might not be the one you want
+                       (e.g. the search might have returned a manual much
+                       older than the Yocto Project version with which you
+                       are working).
+                       You can see all Yocto Project major releases by
+                       visiting the
+                       <ulink url='&YOCTO_WIKI_URL;/wiki/Releases'>Releases</ulink>
+                       page.
+                       If you need a version of this manual for a different
+                       Yocto Project release, visit the
+                       <ulink url='&YOCTO_DOCS_URL;'>Yocto Project documentation page</ulink>
+                       and select the manual set by using the
+                       "ACTIVE RELEASES DOCUMENTATION" or "DOCUMENTS ARCHIVE"
+                       pull-down menus.
+                       </para></listitem>
+                   <listitem>
+                       <para>
+                       To report any inaccuracies or problems with this
+                       (or any other Yocto Project) manual, send an email to
+                       the Yocto Project documentation mailing list at
+                       <filename>docs@lists.yoctoproject.org</filename> or
+                       log into the freenode <filename>#yocto</filename> channel.
+                       </para>
+                   </listitem>
+               </itemizedlist>
+           </note>
+    </legalnotice>
+
+    </bookinfo>
+
+    <xi:include href="kernel-dev-intro.xml"/>
+
+    <xi:include href="kernel-dev-common.xml"/>
+
+    <xi:include href="kernel-dev-advanced.xml"/>
+
+    <xi:include href="kernel-dev-concepts-appx.xml"/>
+
+    <xi:include href="kernel-dev-maint-appx.xml"/>
+
+    <xi:include href="kernel-dev-faq.xml"/>
+
+<!--    <index id='index'>
+      <title>Index</title>
+    </index>
+-->
+
+</book>
+<!--
+vim: expandtab tw=80 ts=4
+-->