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kernel-dev: Edits to the devtool kernel development method.

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Changes based on a run through of the procedure.

(From yocto-docs rev: 0a526bb15f597843d1e5da1eeca0a952c6c5016f)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Scott Rifenbark
2017-09-21 16:55:18 -07:00
committed by Richard Purdie
parent b673c3b990
commit 8f7df8648a
1 changed files with 147 additions and 154 deletions
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301
documentation/kernel-dev/kernel-dev-common.xml
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@@ -70,7 +70,7 @@
<listitem><para> <listitem><para>
<emphasis>Initialize the BitBake Environment:</emphasis> <emphasis>Initialize the BitBake Environment:</emphasis>
Before building an extensible SDK, you need to Before building an extensible SDK, you need to
initialize the BitBake build environment by sourcing a initialize the BitBake build environment by sourcing the
build environment script build environment script
(i.e. <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>): (i.e. <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>):
<literallayout class='monospaced'> <literallayout class='monospaced'>
@@ -155,8 +155,8 @@
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Build the Extensible SDK:</emphasis> <emphasis>Build the Extensible SDK:</emphasis>
Use BitBake to build the extensible SDK specifically for Use BitBake to build the extensible SDK specifically
the Minnowboard: for use with images to be run using QEMU:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ cd ~/poky/build $ cd ~/poky/build
$ bitbake core-image-minimal -c populate_sdk_ext $ bitbake core-image-minimal -c populate_sdk_ext
@@ -280,7 +280,7 @@
<listitem><para> <listitem><para>
<emphasis>Initialize the BitBake Environment:</emphasis> <emphasis>Initialize the BitBake Environment:</emphasis>
Before you can do anything using BitBake, you need to Before you can do anything using BitBake, you need to
initialize the BitBake build environment by sourcing a initialize the BitBake build environment by sourcing the
build environment script build environment script
(i.e. <ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>oe-init-build-env</filename></ulink>). (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 Also, for this example, be sure that the local branch
@@ -1009,66 +1009,58 @@
"<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop using <filename>devtool</filename></link>" "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop using <filename>devtool</filename></link>"
Section. Section.
</note> </note>
</para> <orderedlist>
<listitem><para>
<para> <emphasis>Check Out the Kernel Source Files:</emphasis>
Also, for more information on patching the kernel, see the First you must use <filename>devtool</filename> to checkout
"<link linkend='applying-patches'>Applying Patches</link>" the kernel source code in its workspace.
section. Be sure you are in the terminal set up to do work
</para> with the extensible SDK.
<note>
<orderedlist> See this
<listitem><para> <link linkend='setting-up-the-esdk-terminal'>step</link>
<emphasis>Check Out the Kernel Source Files:</emphasis> in the
First you must use <filename>devtool</filename> to checkout "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop Using <filename>devtool</filename></link>"
the kernel source code in its workspace. section for more information.
Be sure you are in the terminal set up to do work </note>
with the extensible SDK. Use the following <filename>devtool</filename> command
<note> to check out the code:
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'> <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 ERROR: Taskhash mismatch 2c793438c2d9f8c3681fd5f7bc819efa versus
be3a89ce7c47178880ba7bf6293d7404 for be3a89ce7c47178880ba7bf6293d7404 for
/path/to/esdk/layers/poky/meta/recipes-kernel/linux/linux-yocto_4.10.bb.do_unpack /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> </literallayout>
</para></listitem> You can safely ignore these messages.
<listitem><para> The source code is correctly checked out.
<emphasis>Edit the source file</emphasis>: </note>
Edit the <filename>init/calibrate.c</filename> file to have </para></listitem>
the following changes: <listitem><para>
<literallayout class='monospaced'> <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) void calibrate_delay(void)
{ {
unsigned long lpj; unsigned long lpj;
@@ -1085,110 +1077,111 @@
. .
. .
. .
</literallayout> </literallayout>
</para></listitem> </para></listitem>
</orderedlist> </orderedlist>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Build the Updated Kernel Source:</emphasis> <emphasis>Build the Updated Kernel Source:</emphasis>
To build the updated kernel source, use To build the updated kernel source, use
<filename>devtool</filename>: <filename>devtool</filename>:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ devtool build linux-yocto $ devtool build linux-yocto
</literallayout> </literallayout>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Create the Image With the New Kernel:</emphasis> <emphasis>Create the Image With the New Kernel:</emphasis>
Use the <filename>devtool build-image</filename> command Use the <filename>devtool build-image</filename> command
to create a new image that has the new kernel. to create a new image that has the new kernel.
<note> <note>
If the image you originally created resulted in a Wic If the image you originally created resulted in a Wic
file, you can use an alternate method to create the new file, you can use an alternate method to create the new
image with the updated kernel. image with the updated kernel.
For an example, see the steps in the For an example, see the steps in the
<ulink url='https://wiki.yoctoproject.org/wiki/TipsAndTricks/KernelDevelopmentWithEsdk'>TipsAndTricks/KernelDevelopmentWithEsdk</ulink> <ulink url='https://wiki.yoctoproject.org/wiki/TipsAndTricks/KernelDevelopmentWithEsdk'>TipsAndTricks/KernelDevelopmentWithEsdk</ulink>
Wiki Page. Wiki Page.
</note> </note>
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ cd ~ $ cd ~
$ devtool build-image core-image-minimal $ devtool build-image core-image-minimal
</literallayout> </literallayout>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Test the New Image:</emphasis> <emphasis>Test the New Image:</emphasis>
For this example, you can run the new image using QEMU For this example, you can run the new image using QEMU
to verify your changes: to verify your changes:
<orderedlist> <orderedlist>
<listitem><para> <listitem><para>
<emphasis>Boot the image</emphasis>: <emphasis>Boot the image</emphasis>:
Boot the modified image in the QEMU emulator Boot the modified image in the QEMU emulator
using this command: using this command:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ runqemu qemux86 $ runqemu qemux86
</literallayout> </literallayout>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Verify the changes</emphasis>: <emphasis>Verify the changes</emphasis>:
Log into the machine using <filename>root</filename> Log into the machine using <filename>root</filename>
with no password and then use the following shell with no password and then use the following shell
command to scroll through the console's boot output. command to scroll through the console's boot output.
<literallayout class='monospaced'> <literallayout class='monospaced'>
# dmesg | less # dmesg | less
</literallayout> </literallayout>
You should see the results of your You should see the results of your
<filename>printk</filename> statements <filename>printk</filename> statements
as part of the output when you scroll down the as part of the output when you scroll down the
console window. console window.
</para></listitem> </para></listitem>
</orderedlist> </orderedlist>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Stage and commit your changes</emphasis>: <emphasis>Stage and commit your changes</emphasis>:
Within your eSDK terminal, change your working directory to Within your eSDK terminal, change your working directory to
where you modified the <filename>calibrate.c</filename> where you modified the <filename>calibrate.c</filename>
file and use these Git commands to stage and commit your file and use these Git commands to stage and commit your
changes: changes:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ cd ~/poky_sdk/workspace/sources/linux-yocto $ cd ~/poky_sdk/workspace/sources/linux-yocto
$ git status $ git status
$ git add init/calibrate.c $ git add init/calibrate.c
$ git commit -m "calibrate: Add printk example" $ git commit -m "calibrate: Add printk example"
</literallayout> </literallayout>
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Export the Patches and Create a <filename>.bbappend</filename>:</emphasis> <emphasis>Export the Patches and Create an Append File:</emphasis>
To export your commits as patches and create a To export your commits as patches and create a
<filename>.bbappend</filename> file, use the following <filename>.bbappend</filename> file, use the following
command in the terminal used to work with the extensible command in the terminal used to work with the extensible
SDK. SDK.
This example uses the previously established layer named This example uses the previously established layer named
<filename>meta-mylayer</filename>. <filename>meta-mylayer</filename>.
<note> <note>
See Step 3 of the See Step 3 of the
"<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop using devtool</link>" "<link linkend='getting-ready-to-develop-using-devtool'>Getting Ready to Develop using devtool</link>"
section for information on setting up this layer. section for information on setting up this layer.
</note> </note>
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ devtool finish linux-yocto /path/to/meta-mylayer $ devtool finish linux-yocto ~/meta-mylayer
</literallayout> </literallayout>
Once the command finishes, the patches and the Once the command finishes, the patches and the
<filename>.bbappend</filename> file are located in the <filename>.bbappend</filename> file are located in the
<filename>~/meta-mylayer/recipes-kernel/linux</filename> <filename>~/meta-mylayer/recipes-kernel/linux</filename>
directory. directory.
</para></listitem> </para></listitem>
<listitem><para> <listitem><para>
<emphasis>Build the Image With Your Modified Kernel:</emphasis> <emphasis>Build the Image With Your Modified Kernel:</emphasis>
You can now build an image that includes your kernel You can now build an image that includes your kernel
patches. patches.
Execute the following command from your Execute the following command from your
<ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink> <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
in the terminal set up to run BitBake: in the terminal set up to run BitBake:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ cd ~/poky/build $ cd ~/poky/build
$ bitbake core-image-minimal $ bitbake core-image-minimal
</literallayout> </literallayout>
</para></listitem> </para></listitem>
</orderedlist> </orderedlist>
</para>
</section> </section>
<section id="using-traditional-kernel-development-to-patch-the-kernel"> <section id="using-traditional-kernel-development-to-patch-the-kernel">
@@ -1441,8 +1434,8 @@
following sequence of commands: following sequence of commands:
<literallayout class='monospaced'> <literallayout class='monospaced'>
$ cd ~/poky/build $ cd ~/poky/build
$ cd bitbake -c cleanall yocto-linux $ bitbake -c cleanall yocto-linux
$ cd bitbake core-image-minimal -c cleanall $ bitbake core-image-minimal -c cleanall
$ bitbake core-image-minimal $ bitbake core-image-minimal
$ runqemu qemux86 $ runqemu qemux86
</literallayout> </literallayout>