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Documentation: kernel-manual - Removed all trailing whitespace. 

(From yocto-docs rev: 188e1ad10217ff1a6a8363f100bff4e9ef3b9bf7)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark 2012-12-07 17:25:45 -06:00 committed by Richard Purdie
parent 72d01bf43d
commit acb3f72afa
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2
documentation/kernel-manual/kernel-concepts.xml
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@ -146,7 +146,7 @@
Yocto Project and provides information
on the mechanisms used to achieve that architecture.
</para>
<section id='architecture-overview'>
<title>Overview</title>
<para>

26
documentation/kernel-manual/kernel-doc-intro.xml
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@ -10,9 +10,9 @@
<title>Introduction</title>
<para>
The Yocto Project presents kernels as a fully patched, history-clean Git
repositories.
repositories.
Each repository represents selected features, board support,
and configurations extensively tested by the Yocto Project.
and configurations extensively tested by the Yocto Project.
Yocto Project kernels allow the end user to leverage community
best practices to seamlessly manage the development, build and debug cycles.
</para>
@ -22,14 +22,14 @@
The manual consists of two sections:
<itemizedlist>
<listitem><para><emphasis>Concepts:</emphasis> Describes concepts behind a kernel.
You will understand how a kernel is organized and why it is organized in
the way it is. You will understand the benefits of a kernel's organization
and the mechanisms used to work with the kernel and how to apply it in your
You will understand how a kernel is organized and why it is organized in
the way it is. You will understand the benefits of a kernel's organization
and the mechanisms used to work with the kernel and how to apply it in your
design process.</para></listitem>
<listitem><para><emphasis>Using a Kernel:</emphasis> Describes best practices
<listitem><para><emphasis>Using a Kernel:</emphasis> Describes best practices
and "how-to" information
that lets you put a kernel to practical use.
Some examples are how to examine changes in a branch and how to
that lets you put a kernel to practical use.
Some examples are how to examine changes in a branch and how to
save kernel modifications.</para></listitem>
</itemizedlist>
</para>
@ -39,8 +39,8 @@
<itemizedlist>
<listitem><para>The Linux Foundation's guide for kernel development
process - <ulink url='http://www.linuxfoundation.org/content/1-guide-kernel-development-process'></ulink></para></listitem>
<listitem><para>A fairly encompassing guide on Linux kernel development -
<ulink url='http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob_plain;f=Documentation/HOWTO;hb=HEAD'></ulink></para></listitem>
<listitem><para>A fairly encompassing guide on Linux kernel development -
<ulink url='http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob_plain;f=Documentation/HOWTO;hb=HEAD'></ulink></para></listitem>
</itemizedlist>
</para>
@ -53,14 +53,14 @@
<listitem><para>
"<ulink url='&YOCTO_DOCS_DEV_URL;#kernel-modification-workflow'>Kernel Modification Workflow</ulink>"
</para></listitem>
<listitem><para>
<listitem><para>
"<ulink url='&YOCTO_DOCS_DEV_URL;#patching-the-kernel'>Patching the Kernel</ulink>"</para></listitem>
<listitem><para>
<listitem><para>
"<ulink url='&YOCTO_DOCS_DEV_URL;#configuring-the-kernel'>Configuring the Kernel</ulink>"</para></listitem>
</itemizedlist>
</para>
<para>
<para>
For general information on the Yocto Project, visit the website at
<ulink url='&YOCTO_HOME_URL;'></ulink>.
</para>

344
documentation/kernel-manual/kernel-how-to.xml
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@ -10,11 +10,11 @@
<section id='actions-org'>
<title>Introduction</title>
<para>
This chapter describes how to accomplish tasks involving a kernel's tree structure.
The information is designed to help the developer that wants to modify the Yocto
This chapter describes how to accomplish tasks involving a kernel's tree structure.
The information is designed to help the developer that wants to modify the Yocto
Project kernel and contribute changes upstream to the Yocto Project.
The information covers the following:
<itemizedlist>
<itemizedlist>
<listitem><para>Tree construction</para></listitem>
<listitem><para>Build strategies</para></listitem>
<listitem><para>Workflow examples</para></listitem>
@ -25,72 +25,72 @@
<section id='tree-construction'>
<title>Tree Construction</title>
<para>
This section describes construction of the Yocto Project kernel source repositories
This section describes construction of the Yocto Project kernel source repositories
as accomplished by the Yocto Project team to create kernel repositories.
These kernel repositories are found under the heading "Yocto Linux Kernel" at
<ulink url='&YOCTO_GIT_URL;/cgit.cgi'>&YOCTO_GIT_URL;/cgit.cgi</ulink>
and can be shipped as part of a Yocto Project release.
and can be 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/feature
in the product.
in the product.
Those feature descriptions list all necessary patches,
configuration, branching, tagging and feature divisions found in a kernel.
Thus, the Yocto Project kernel repository (or tree) is built.
</para>
<para>
The existence of this tree allows you to access and clone a particular
The existence of this tree allows you to access and clone a particular
Yocto Project 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 kernel in any clone of the Yocto Project kernel source repository
You can find the files used to describe all the valid features and BSPs
in the Yocto Project kernel in any clone of the Yocto Project kernel source repository
Git tree.
For example, the following command clones the Yocto Project baseline kernel that
For example, the following command clones the Yocto Project baseline kernel that
branched off of <filename>linux.org</filename> version 3.4:
<literallayout class='monospaced'>
$ git clone git://git.yoctoproject.org/linux-yocto-3.4
</literallayout>
For another example of how to set up a local Git repository of the Yocto Project
kernel files, see the
"<ulink url='&YOCTO_DOCS_DEV_URL;#local-kernel-files'>Yocto Project Kernel</ulink>" bulleted
kernel files, see the
"<ulink url='&YOCTO_DOCS_DEV_URL;#local-kernel-files'>Yocto Project Kernel</ulink>" bulleted
item in the Yocto Project Development Manual.
</para>
<para>
Once you have cloned the kernel Git repository on your local machine, you can
<para>
Once you have cloned the kernel Git repository on your local machine, you can
switch to the <filename>meta</filename> branch within the repository.
Here is an example that assumes the local Git repository for the kernel is in
Here is an example that assumes the local Git repository for the kernel is in
a top-level directory named <filename>linux-yocto-3.4</filename>:
<literallayout class='monospaced'>
$ cd ~/linux-yocto-3.4
$ git checkout -b meta origin/meta
</literallayout>
Once you have checked out and switched to the <filename>meta</filename> branch,
you can see a snapshot of all the kernel configuration and feature descriptions that are
you can see a snapshot of all the kernel configuration and feature descriptions that are
used to build that particular kernel repository.
These descriptions are in the form of <filename>.scc</filename> files.
These descriptions are in the form of <filename>.scc</filename> files.
</para>
<para>
You should realize, however, that browsing your local kernel repository
for feature descriptions and patches is not an effective way to determine what is in a
particular kernel branch.
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.
Using Git is an efficient and flexible way to inspect changes to the kernel.
For examples showing how to use Git to inspect kernel commits, see the following sections
in this chapter.
<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
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;/cgit.cgi'></ulink> given the
introduction of a new top-level kernel feature or BSP.
These are the actions that effectively create the tree
the Yocto Project kernel source Git repository (or tree) found at
<ulink url='&YOCTO_GIT_URL;/cgit.cgi'></ulink> given the
introduction of a new top-level kernel feature or BSP.
These are the actions that effectively create the tree
that includes the new feature, patch or BSP:
<orderedlist>
<listitem><para>A top-level kernel feature is passed to the kernel build subsystem.
@ -103,7 +103,7 @@
<listitem><para>Areas pointed to by <filename>SRC_URI</filename> statements
found in recipes</para></listitem>
</itemizedlist>
For a typical build, the target of the search is a
For a typical build, the target of the search is a
feature description in an <filename>.scc</filename> file
whose name follows this format:
<literallayout class='monospaced'>
@ -113,19 +113,19 @@
<listitem><para>Once located, the feature description is either compiled into a simple script
of actions, or into an existing equivalent script that is already part of the
shipped kernel.</para></listitem>
<listitem><para>Extra features are appended to the top-level feature description.
These features can come from the
<listitem><para>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>Each extra feature is located, compiled and appended to the script
<listitem><para>Each extra feature is located, compiled and appended to the script
as described in step three.</para></listitem>
<listitem><para>The script is executed to produce a series of <filename>meta-*</filename>
directories.
directories.
These directories 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>The base repository is cloned, and the actions
listed in the <filename>meta-*</filename> directories are applied to the
listed in the <filename>meta-*</filename> directories are applied to the
tree.</para></listitem>
<listitem><para>The Git repository is left with the desired branch checked out and any
required branching, patching and tagging has been performed.</para></listitem>
@ -133,17 +133,17 @@
</para>
<para>
The kernel tree is now ready for developer consumption to be locally cloned,
configured, and built into a Yocto Project kernel specific to some target hardware.
<note><para>The generated <filename>meta-*</filename> directories add 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
configured, and built into a Yocto Project kernel specific to some target hardware.
<note><para>The generated <filename>meta-*</filename> directories add 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;/cgit.cgi'>http://git.yoctoproject.org/cgit.cgi</ulink>
is the combination of all supported boards and configurations.</para>
<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.
<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>
</note>
</para>
@ -152,15 +152,15 @@
<section id='build-strategy'>
<title>Build Strategy</title>
<para>
Once a local Git repository of the Yocto Project kernel exists on a development system,
Once a local Git repository of the Yocto Project kernel exists on a development system,
you can consider the compilation phase of kernel development - 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
<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 exists.
This branch has the following form:
@ -171,22 +171,22 @@
<para>
The OpenEmbedded build system makes sure these conditions exist before attempting compilation.
Other means, however, do exist, such as as bootstrapping a BSP, see
Other means, however, do exist, such as as bootstrapping a BSP, see
the "<link linkend='workflow-examples'>Workflow Examples</link>".
</para>
<para>
Before building a kernel, the build process verifies the tree
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.
files.
As the features are compiled, associated kernel configuration fragments are noted
and recorded in the <filename>meta-*</filename> series of directories in their compilation order.
and recorded in the <filename>meta-*</filename> 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
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
processing of that information and generates the final <filename>.config</filename> file
that is used during compilation.
</para>
@ -197,9 +197,9 @@
<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
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
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'>
@ -208,13 +208,13 @@
</para>
<para>
The existing support in the <filename>kernel.org</filename> tree achieves this
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.
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 build directory in its own separate branch
@ -229,18 +229,18 @@
As previously noted, the Yocto Project kernel has built-in Git integration.
However, these utilities are not the only way to work with the kernel repository.
The Yocto Project has not made changes to Git or to other tools that
would invalidate alternate workflows.
Additionally, the way the kernel repository is constructed results in using
only core Git functionality, thus allowing any number of tools or front ends to use the
would invalidate alternate workflows.
Additionally, the way the kernel repository is constructed results in using
only core Git functionality, thus allowing any number of tools or front ends to use the
resulting tree.
</para>
<para>
This section contains several workflow examples.
Many of the examples use Git commands.
You can find Git documentation at
Many of the examples use Git commands.
You can find Git documentation at
<ulink url='http://git-scm.com/documentation'></ulink>.
You can find a simple overview of using Git with the Yocto Project in the
You can find a simple overview of using Git with the Yocto Project in the
"<ulink url='&YOCTO_DOCS_DEV_URL;#git'>Git</ulink>"
section of the Yocto Project Development Manual.
</para>
@ -249,25 +249,25 @@
<title>Change Inspection: Kernel Changes/Commits</title>
<para>
A common question when working with a BSP or kernel is:
A common question when working with a BSP or kernel is:
"What changes have been applied to this tree?"
</para>
<para>
In projects that have a collection of directories that
contain patches to the kernel, it is possible to inspect or "grep" the contents
of the directories to get a general feel for the changes.
contain patches to the kernel, it is possible to inspect or "grep" the contents
of the directories to get a general feel for the changes.
This sort of patch inspection is not an efficient way to determine what has been done to the
kernel.
The reason it is inefficient is because there are many optional patches that are
The reason it is inefficient is because there are many optional patches that are
selected based on the kernel type and the feature description.
Additionally, patches could exist in directories that are not included in the search.
</para>
<para>
A more efficient way to determine what has changed in the kernel is to use
Git and inspect or search the kernel tree.
This method gives you a full view of not only the source code modifications,
Git and inspect or search the kernel tree.
This method gives you a full view of not only the source code modifications,
but also provides the reasons for the changes.
</para>
@ -277,11 +277,11 @@
<para>
Following are a few examples that show how to use Git to examine changes.
Because the Yocto Project Git repository does not break existing Git
functionality and because there exists many permutations of these types of
functionality and because there exists many permutations of these types of
commands, there are many more methods to discover changes.
<note>
Unless you provide a commit range
(&lt;kernel-type&gt;..&lt;bsp&gt;-&lt;kernel-type&gt;), <filename>kernel.org</filename> history
Unless you provide a commit range
(&lt;kernel-type&gt;..&lt;bsp&gt;-&lt;kernel-type&gt;), <filename>kernel.org</filename> history
is blended with Yocto Project changes.
</note>
<literallayout class='monospaced'>
@ -301,27 +301,27 @@
# determine the change history of a particular file
&gt; git whatchanged &lt;path to file&gt;
# determine the commits which touch each line in a file
&gt; git blame &lt;path to file&gt;
</literallayout>
</para>
</section>
<section id='show-a-particular-feature-or-branch-change'>
<title>Show a Particular Feature or Branch Change</title>
<para>
Developers use tags in the Yocto Project kernel tree to divide changes for significant
features or branches.
Once you know a particular tag, you can use Git commands
Developers use tags in the Yocto Project kernel tree to divide changes for significant
features or branches.
Once you know a particular tag, you can use Git commands
to show changes associated with the tag and find the branches that contain
the feature.
the feature.
<note>
Because BSP branch, <filename>kernel.org</filename>, and feature tags are all
Because BSP branch, <filename>kernel.org</filename>, and feature tags are all
present, there could be many tags.
</note>
The <filename>git show &lt;tag&gt;</filename> command shows changes that are tagged by
The <filename>git show &lt;tag&gt;</filename> command shows changes that are tagged by
a feature.
Here is an example that shows changes tagged by the <filename>systemtap</filename>
feature:
@ -339,7 +339,7 @@
<para>
You can use many other comparisons to isolate BSP and kernel changes.
For example, you can compare against <filename>kernel.org</filename> tags
For example, you can compare against <filename>kernel.org</filename> tags
such as the <filename>v3.4</filename> tag.
</para>
</section>
@ -350,29 +350,29 @@
<para>
Another common operation is to build a BSP supplied by the Yocto Project, make some
changes, rebuild, and then test.
changes, rebuild, and then test.
Those local changes often need to be exported, shared or otherwise maintained.
</para>
<para>
Since the Yocto Project kernel source tree is backed by Git, this activity is
much easier as compared to with previous releases.
Because Git tracks file modifications, additions and deletions, it is easy
much easier as compared to with previous releases.
Because Git tracks file modifications, additions and deletions, it is easy
to modify the code and later realize that you need to save the changes.
It is also easy to determine what has changed.
It is also easy to determine what has changed.
This method also provides many tools to commit, undo and export those modifications.
</para>
<para>
This section and its sub-sections, describe general application of Git's
<filename>push</filename> and <filename>pull</filename> commands, which are used to
get your changes upstream or source your code from an upstream repository.
The Yocto Project provides scripts that help you work in a collaborative development
environment.
This section and its sub-sections, describe general application of Git's
<filename>push</filename> and <filename>pull</filename> commands, which are used to
get your changes upstream or source your code from an upstream repository.
The Yocto Project provides scripts that help you work in a collaborative development
environment.
For information on these scripts, see the
"<ulink url='&YOCTO_DOCS_DEV_URL;#pushing-a-change-upstream'>Using Scripts to Push a Change
Upstream and Request a Pull</ulink>" and
"<ulink url='&YOCTO_DOCS_DEV_URL;#submitting-a-patch'>Using Email to Submit a Patch</ulink>"
"<ulink url='&YOCTO_DOCS_DEV_URL;#pushing-a-change-upstream'>Using Scripts to Push a Change
Upstream and Request a Pull</ulink>" and
"<ulink url='&YOCTO_DOCS_DEV_URL;#submitting-a-patch'>Using Email to Submit a Patch</ulink>"
sections in the Yocto Project Development Manual.
</para>
@ -380,7 +380,7 @@
There are many ways to save kernel modifications.
The technique employed
depends on the destination for the patches:
<itemizedlist>
<listitem><para>Bulk storage</para></listitem>
<listitem><para>Internal sharing either through patches or by using Git</para></listitem>
@ -391,7 +391,7 @@
</para>
<para>
Because of the following list of issues, the destination of the patches also influences
Because of the following list of issues, the destination of the patches also influences
the method for gathering them:
<itemizedlist>
@ -405,24 +405,24 @@
<title>Bulk Export</title>
<para>
This section describes how you can "bulk" export changes that have not
been separated or divided.
This situation works well when you are simply storing patches outside of the kernel
source repository, either permanently or temporarily, and you are not committing
This section describes how you can "bulk" export changes that have not
been separated or divided.
This situation works well when you are simply storing patches outside of the kernel
source repository, either permanently or temporarily, and you are not committing
incremental changes during development.
<note>
This technique is not appropriate for full integration of upstream submission
because changes are not properly divided and do not provide an avenue for per-change
commit messages.
Therefore, this example assumes that changes have not been committed incrementally
commit messages.
Therefore, this example assumes that changes have not been committed incrementally
during development and that you simply must gather and export them.
</note>
<literallayout class='monospaced'>
# bulk export of ALL modifications without separation or division
# of the changes
# of the changes
$ git add .
$ git commit -s -a -m &lt;msg&gt;
$ git commit -s -a -m &lt;msg&gt;
or
$ git commit -s -a # and interact with $EDITOR
</literallayout>
@ -447,8 +447,8 @@
<para>
This section describes how to save modifications when you are making incremental
commits or practicing planned sharing.
The examples in this section assume that you have incrementally committed
changes to the tree during development and now need to export them.
The examples in this section assume that you have incrementally committed
changes to the tree during development and now need to export them.
The sections that follow
describe how you can export your changes internally through either patches or by
using Git commands.
@ -456,7 +456,7 @@
<para>
During development, the following commands are of interest.
For full Git documentation, refer to the Git documentation at
For full Git documentation, refer to the Git documentation at
<ulink url='http://github.com'></ulink>.
<literallayout class='monospaced'>
@ -476,15 +476,15 @@
</para>
<para>
Distributed development with Git is possible when you use a universally
Distributed development with Git is possible when you use a universally
agreed-upon unique commit identifier (set by the creator of the commit) that maps to a
specific change set with a specific parent.
specific change set with a specific parent.
This identifier is created for you when
you create a commit, and is re-created when you amend, alter or re-apply
a commit.
a commit.
As an individual in isolation, this is of no interest.
However, if you
intend to share your tree with normal Git <filename>push</filename> and
intend to share your tree with normal Git <filename>push</filename> and
<filename>pull</filename> operations for
distributed development, you should consider the ramifications of changing a
commit that you have already shared with others.
@ -492,7 +492,7 @@
<para>
Assuming that the changes have not been pushed upstream, or pulled into
another repository, you can update both the commit content and commit messages
another repository, you can update both the commit content and commit messages
associated with development by using the following commands:
<literallayout class='monospaced'>
@ -502,7 +502,7 @@
</literallayout>
</para>
<para>
<para>
Again, assuming that the changes have not been pushed upstream, and that
no pending works-in-progress exist (use <filename>git status</filename> to check), then
you can revert (undo) commits by using the following commands:
@ -521,12 +521,12 @@
<para>
You can create branches, "cherry-pick" changes, or perform any number of Git
operations until the commits are in good order for pushing upstream
or for pull requests.
After a <filename>push</filename> or <filename>pull</filename> command,
or for pull requests.
After a <filename>push</filename> or <filename>pull</filename> command,
commits are normally considered
"permanent" and you should not modify them.
If the commits need to be changed, you can incrementally do so with new commits.
These practices follow standard Git workflow and the <filename>kernel.org</filename> best
These practices follow standard Git workflow and the <filename>kernel.org</filename> best
practices, which is recommended.
<note>
It is recommended to tag or branch before adding changes to a Yocto Project
@ -535,26 +535,26 @@
reference point to facilitate locating and exporting local changes.
</note>
</para>
<section id='export-internally-via-patches'>
<title>Exporting Changes Internally by Using Patches</title>
<para>
This section describes how you can extract committed changes from a working directory
by exporting them as patches.
Once the changes have been extracted, you can use the patches for upstream submission,
Once the changes have been extracted, you can use the patches for upstream submission,
place them in a Yocto Project template for automatic kernel patching,
or apply them in many other common uses.
</para>
<para>
This example shows how to create a directory with sequentially numbered patches.
Once the directory is created, you can apply it to a repository using the
<filename>git am</filename> command to reproduce the original commit and all
Once the directory is created, you can apply it to a repository using the
<filename>git am</filename> command to reproduce the original commit and all
the related information such as author, date, commit log, and so forth.
<note>
The new commit identifiers (ID) will be generated upon re-application.
This action reflects that the commit is now applied to an underlying commit
The new commit identifiers (ID) will be generated upon re-application.
This action reflects that the commit is now applied to an underlying commit
with a different ID.
</note>
<literallayout class='monospaced'>
@ -581,19 +581,19 @@
$ git format-patch -o &lt;save dir&gt; &lt;commit id&gt;
$ git format-patch -o &lt;save dir&gt; &lt;rev-list&gt;
</literallayout>
</para>
</section>
</para>
</section>
<section id='export-internally-via-git'>
<title>Exporting Changes Internally by Using Git</title>
<para>
This section describes how you can export changes from a working directory
This section describes how you can export changes from a working directory
by pushing the changes into a master repository or by making a pull request.
Once you have pushed the changes to the master repository, you can then
Once you have pushed the changes to the master repository, you can then
pull those same changes into a new kernel build at a later time.
</para>
<para>
Use this command form to push the changes:
<literallayout class='monospaced'>
@ -604,7 +604,7 @@
<para>
For example, the following command pushes the changes from your local branch
<filename>yocto/standard/common-pc/base</filename> to the remote branch with the same name
<filename>yocto/standard/common-pc/base</filename> to the remote branch with the same name
in the master repository <filename>//git.mycompany.com/pub/git/kernel-3.4</filename>.
<literallayout class='monospaced'>
$ git push ssh://git.mycompany.com/pub/git/kernel-3.4 \
@ -613,7 +613,7 @@
</para>
<para>
A pull request entails using the <filename>git request-pull</filename> command to compose
A pull request entails using the <filename>git request-pull</filename> command to compose
an email to the
maintainer requesting that a branch be pulled into the master repository, see
<ulink url='http://github.com/guides/pull-requests'></ulink> for an example.
@ -622,7 +622,7 @@
changes, but are not covered in this document.
</note>
</para>
</section>
</section>
</section>
<section id='export-for-external-upstream-submission'>
@ -636,12 +636,12 @@
This method allows easy review and integration of the changes.
<note>
Before sending patches for review be sure you understand the
community standards for submitting and documenting changes and follow their best practices.
community standards for submitting and documenting changes and follow their best practices.
For example, kernel patches should follow standards such as:
<itemizedlist>
<listitem><para>
<ulink url='http://linux.yyz.us/patch-format.html'></ulink></para></listitem>
<listitem><para>Documentation/SubmittingPatches (in any linux
<listitem><para>Documentation/SubmittingPatches (in any linux
kernel source tree)</para></listitem>
</itemizedlist>
</note>
@ -651,30 +651,30 @@
The messages used to commit changes are a large part of these standards.
Consequently, be sure that the headers for each commit have the required information.
For information on how to follow the Yocto Project commit message standards, see the
"<ulink url='&YOCTO_DOCS_DEV_URL;#how-to-submit-a-change'>How to Submit a
"<ulink url='&YOCTO_DOCS_DEV_URL;#how-to-submit-a-change'>How to Submit a
Change</ulink>" section in the Yocto Project Development Manual.
</para>
<para>
If the initial commits were not properly documented or do not meet those standards,
you can re-base by using the <filename>git rebase -i</filename> command to
you can re-base by using the <filename>git rebase -i</filename> command to
manipulate the commits and
get them into the required format.
get them into the required format.
Other techniques such as branching and cherry-picking commits are also viable options.
</para>
<para>
Once you complete the commits, you can generate the email that sends the patches
to the maintainer(s) or lists that review and integrate changes.
The command <filename>git send-email</filename> is commonly used to ensure
that patches are properly
Once you complete the commits, you can generate the email that sends the patches
to the maintainer(s) or lists that review and integrate changes.
The command <filename>git send-email</filename> is commonly used to ensure
that patches are properly
formatted for easy application and avoid mailer-induced patch damage.
</para>
<para>
The following is an example of dumping patches for external submission:
<literallayout class='monospaced'>
# dump the last 4 commits
# dump the last 4 commits
$ git format-patch --thread -n -o ~/rr/ HEAD^^^^
$ git send-email --compose --subject '[RFC 0/N] &lt;patch series summary&gt;' \
--to foo@yoctoproject.org --to bar@yoctoproject.org \
@ -690,17 +690,17 @@
<para>
When you want to export changes for import into another
Source Code Manager (SCM), you can use any of the previously discussed
Source Code Manager (SCM), you can use any of the previously discussed
techniques.
However, if the patches are manually applied to a secondary tree and then
that tree is checked into the SCM, you can lose change information such as
However, if the patches are manually applied to a secondary tree and then
that tree is checked into the SCM, you can lose change information such as
commit logs.
This process is not recommended.
</para>
<para>
Many SCMs can directly import Git commits, or can translate Git patches so that
information is not lost.
information is not lost.
Those facilities are SCM-dependent and you should use them whenever possible.
</para>
</section>
@ -710,15 +710,15 @@
<title>Working with the Yocto Project Kernel in Another SCM</title>
<para>
This section describes kernel development in an SCM other than Git,
This section describes kernel development in an SCM other than Git,
which is not the same as exporting changes to another SCM described earlier.
For this scenario, you use the OpenEmbedded build system to
For this scenario, you use the OpenEmbedded build system to
develop the kernel in a different SCM.
The following must be true for you to accomplish this:
<itemizedlist>
<listitem><para>The delivered Yocto Project kernel must be exported into the second
SCM.</para></listitem>
<listitem><para>Development must be exported from that secondary SCM into a
<listitem><para>Development must be exported from that secondary SCM into a
format that can be used by the OpenEmbedded build system.</para></listitem>
</itemizedlist>
</para>
@ -728,7 +728,7 @@
<para>
Depending on the SCM, it might be possible to export the entire Yocto Project
kernel Git repository, branches and all, into a new environment.
kernel Git repository, branches and all, into a new environment.
This method is preferred because it has the most flexibility and potential to maintain
the meta data associated with each commit.
</para>
@ -750,11 +750,11 @@
</para>
<para>
You could now relocate the CVS repository and use it in a centralized manner.
You could now relocate the CVS repository and use it in a centralized manner.
</para>
<para>
The following commands illustrate how you can condense and merge two BSPs into a
The following commands illustrate how you can condense and merge two BSPs into a
second SCM:
<literallayout class='monospaced'>
$ git checkout yocto/standard/common-pc/base
@ -768,7 +768,7 @@
<section id='importing-changes-for-build'>
<title>Importing Changes for the Build</title>
<para>
Once development has reached a suitable point in the second development
environment, you need to export the changes as patches.
@ -782,12 +782,12 @@
<title>Creating a BSP Based on an Existing Similar BSP</title>
<para>
This section overviews the process of creating a BSP based on an
This section overviews the process of creating a BSP based on an
existing similar BSP.
The information is introductory in nature and does not provide step-by-step examples.
The information is introductory in nature and does not provide step-by-step examples.
For detailed information on how to create a new BSP, see
the "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'>Creating a New BSP Layer Using the yocto-bsp Script</ulink>" section in the
Yocto Project Board Support Package (BSP) Developer's Guide, or see the
the "<ulink url='&YOCTO_DOCS_BSP_URL;#creating-a-new-bsp-layer-using-the-yocto-bsp-script'>Creating a New BSP Layer Using the yocto-bsp Script</ulink>" section in the
Yocto Project Board Support Package (BSP) Developer's Guide, or see the
<ulink url='&YOCTO_WIKI_URL;/wiki/Transcript:_creating_one_generic_Atom_BSP_from_another'>Transcript:_creating_one_generic_Atom_BSP_from_another</ulink>
wiki page.
</para>
@ -796,42 +796,42 @@
The basic steps you need to follow are:
<orderedlist>
<listitem><para><emphasis>Make sure you have set up a local Source Directory:</emphasis>
You must create a local
<ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>
by either creating a Git repository (recommended) or
You must create a local
<ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>
by either creating a Git repository (recommended) or
extracting a Yocto Project release tarball.</para></listitem>
<listitem><para><emphasis>Choose an existing BSP available with the Yocto Project:</emphasis>
Try to map your board features as closely to the features of a BSP that is
already supported and exists in the Yocto Project.
Starting with something as close as possible to your board makes developing
your BSP easier.
You can find all the BSPs that are supported and ship with the Yocto Project
on the Yocto Project's Download page at
Try to map your board features as closely to the features of a BSP that is
already supported and exists in the Yocto Project.
Starting with something as close as possible to your board makes developing
your BSP easier.
You can find all the BSPs that are supported and ship with the Yocto Project
on the Yocto Project's Download page at
<ulink url='&YOCTO_HOME_URL;/download'></ulink>.</para></listitem>
<listitem><para><emphasis>Be sure you have the Base BSP:</emphasis>
You need to either have a local Git repository of the base BSP set up or
You need to either have a local Git repository of the base BSP set up or
have downloaded and extracted the files from a release BSP tarball.
Either method gives you access to the BSP source files.</para></listitem>
<listitem><para><emphasis>Make a copy of the existing BSP, thus isolating your new
<listitem><para><emphasis>Make a copy of the existing BSP, thus isolating your new
BSP work:</emphasis>
Copying the existing BSP file structure gives you a new area in which to work.</para></listitem>
<listitem><para><emphasis>Make configuration and recipe changes to your new BSP:</emphasis>
Configuration changes involve the files in the BSP's <filename>conf</filename>
directory.
Changes include creating a machine-specific configuration file and editing the
<filename>layer.conf</filename> file.
directory.
Changes include creating a machine-specific configuration file and editing the
<filename>layer.conf</filename> file.
The configuration changes identify the kernel you will be using.
Recipe changes include removing, modifying, or adding new recipe files that
Recipe changes include removing, modifying, or adding new recipe files that
instruct the build process on what features to include in the image.</para></listitem>
<listitem><para><emphasis>Prepare for the build:</emphasis>
Before you actually initiate the build, you need to set up the build environment
by sourcing the environment initialization script.
After setting up the environment, you need to make some build configuration
by sourcing the environment initialization script.
After setting up the environment, you need to make some build configuration
changes to the <filename>local.conf</filename> and <filename>bblayers.conf</filename>
files.</para></listitem>
<listitem><para><emphasis>Build the image:</emphasis>
The OpenEmbedded build system uses BitBake to create the image.
You need to decide on the type of image you are going to build (e.g. minimal, base,
The OpenEmbedded build system uses BitBake to create the image.
You need to decide on the type of image you are going to build (e.g. minimal, base,
core, sato, and so forth) and then start the build using the <filename>bitbake</filename>
command.</para></listitem>
</orderedlist>
@ -851,8 +851,8 @@
</para>
<para>
You can use the above Git command to report modified, removed, or added files.
You should commit those changes to the tree regardless of whether they will be saved,
You can use the above Git command to report modified, removed, or added files.
You should commit those changes to the tree regardless of whether they will be saved,
exported, or used.
Once you commit the changes you need to rebuild the kernel.
</para>

16
documentation/kernel-manual/kernel-manual.xml
View File

@ -2,7 +2,7 @@
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
<book id='kernel-manual' lang='en'
<book id='kernel-manual' lang='en'
xmlns:xi="http://www.w3.org/2003/XInclude"
xmlns="http://docbook.org/ns/docbook"
>
@ -10,13 +10,13 @@
<mediaobject>
<imageobject>
<imagedata fileref='figures/kernel-title.png'
format='SVG'
<imagedata fileref='figures/kernel-title.png'
format='SVG'
align='left' scalefit='1' width='100%'/>
</imageobject>
</imageobject>
</mediaobject>
<title></title>
<title></title>
<authorgroup>
<author>
@ -73,7 +73,7 @@
<legalnotice>
<para>
Permission is granted to copy, distribute and/or modify this document under
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>
@ -99,6 +99,6 @@
-->
</book>
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