[gnome-continuous-yocto/gnomeostree-3.28-rocko: 7555/8267] dev-manual, kernel-dev: Working kernel flow process using devtool
- From: Emmanuele Bassi <ebassi src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gnome-continuous-yocto/gnomeostree-3.28-rocko: 7555/8267] dev-manual, kernel-dev: Working kernel flow process using devtool
- Date: Sun, 17 Dec 2017 06:24:45 +0000 (UTC)
commit ea256df2a8af386f5c8c7bc7744d6d790ab0a3f9
Author: Scott Rifenbark <srifenbark gmail com>
Date: Wed Aug 30 13:34:52 2017 -0700
dev-manual, kernel-dev: Working kernel flow process using devtool
A work-in-progress of an example that modifies the kernel
using the devtool. The procedure is not complete yet as it
does not run properly.
(From yocto-docs rev: 462ba2e46f237c294f05805ad5044291a085975d)
Signed-off-by: Scott Rifenbark <srifenbark gmail com>
Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>
documentation/dev-manual/dev-manual-start.xml | 13 +
documentation/kernel-dev/kernel-dev-common.xml | 742 ++++++++++++------------
documentation/kernel-dev/kernel-dev-intro.xml | 22 +-
3 files changed, 408 insertions(+), 369 deletions(-)
---
diff --git a/documentation/dev-manual/dev-manual-start.xml b/documentation/dev-manual/dev-manual-start.xml
index 9459575..aa03d85 100644
--- a/documentation/dev-manual/dev-manual-start.xml
+++ b/documentation/dev-manual/dev-manual-start.xml
@@ -123,6 +123,19 @@
section in the Yocto Project Reference Manual.
</para></listitem>
</orderedlist>
+ Once you have completed the previous steps, you are ready to
+ continue using a given development path on your native Linux
+ machine.
+ If you are going to use BitBake, see the
+ "<link linkend='cloning-the-poky-repository'>Cloning the <filename>poky</filename>
Repository</link>"
+ section.
+ If you are going to use the Extensible SDK, see the
+ "<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-extensible'>Using the Extensible SDK</ulink>"
+ Chapter in the Yocto Project Software Development Kit (SDK)
+ Developer's Guide.
+ If you are going to use Toaster, see the
+ "<ulink url='&YOCTO_DOCS_TOAST_URL;#toaster-manual-setup-and-use'>Setting Up and Using
Toaster</ulink>"
+ section in the Toaster User Manual.
</para>
</section>
diff --git a/documentation/kernel-dev/kernel-dev-common.xml b/documentation/kernel-dev/kernel-dev-common.xml
index cb50912..14381af 100644
--- a/documentation/kernel-dev/kernel-dev-common.xml
+++ b/documentation/kernel-dev/kernel-dev-common.xml
@@ -45,6 +45,67 @@
information.
</note>
</para>
+
+ <para>
+ Following is a detailed example showing how to create a layer
+ without the aid of tools for building the kernel:
+ <orderedlist>
+ <listitem><para>
+ <emphasis>Create additional structure</emphasis>:
+ Create the additional layer structure:
+ <literallayout class='monospaced'>
+ $ cd ~/poky/meta-mylayer
+ $ mkdir conf
+ $ mkdir recipes-kernel
+ $ mkdir recipes-kernel/linux
+ $ mkdir 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
+ your patch file.
+ </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 <filename>linux-yocto_3.4.bbappend</filename> file as follows:
+ <literallayout class='monospaced'>
+ FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+
+ SRC_URI += "file://0001-calibrate-Add-printk-example.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.
+ 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 Manual.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Put the patch file in your layer</emphasis>:
+ Move the <filename>0001-calibrate-Add-printk-example.patch</filename> file to
+ the <filename>meta-mylayer/recipes-kernel/linux/linux-yocto</filename>
+ directory.</para></listitem>
+ </orderedlist>
+ </para>
</section>
<section id='modifying-an-existing-recipe'>
@@ -72,11 +133,9 @@
<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 some general resources.
- You can also see the
- "<link linkend='set-up-your-layer-for-the-build'>Set Up Your Layer for the Build</link>"
- section for a detailed example.
+ 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'>
@@ -452,63 +511,51 @@
<section id="using-devtool-to-patch-the-kernel">
<title>Using <filename>devtool</filename> to Patch the Kernel</title>
-
<para role='writernotes'>
- Some stuff here for the using devtool from the wiki.
- This whole section is WIP.
- <orderedlist>
- <listitem><para role='writernotes'>
- If you are dealing with real hardware, you can flash the
- new kernel image to a USB stick and boot the hardware to
- see it run.
- </para></listitem>
- <listitem><para role='writernotes'>
- Checkout and modify the kernel source.
- This is where you make your changes to the image.
- </para></listitem>
- <listitem><para role='writernotes'>
- Create a new image that uses the altered kernel.
- </para></listitem>
- <listitem><para role='writernotes'>
- If you are working with actual hardware, you can flash
- the new image to a USB stick and use it to boot up the
- hardware.
- You can see your changes in action.
- </para></listitem>
- </orderedlist>
+ This procedure currently does not work.
+ It is WIP.
+ </para>
+
+ <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.
+ 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.
<note>
- You can use the <filename>yocto-kernel</filename> script
+ You can also use the <filename>yocto-kernel</filename> script
found in the <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
under <filename>scripts</filename> to manage kernel patches and configuration.
See the "<ulink
url='&YOCTO_DOCS_BSP_URL;#managing-kernel-patches-and-config-items-with-yocto-kernel'>Managing kernel Patches
and Config Items with yocto-kernel</ulink>"
- section in the Yocto Project Board Support Packages (BSP) Developer's Guide for
- more information.</note>
+ section in the Yocto Project Board Support Packages (BSP)
+ Developer's Guide for more information.
+ </note>
</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.
+ 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.
- </para>
-
- <para>
- The example builds an extensible SDK, which is then used to
- build, using <filename>devtool</filename>, a clean image for the
- default <filename>qemux86</filename> machine in a
- <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
- named <filename>poky</filename>.
- In the example, the
- <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
- is <filename>build</filename> and is located in the default
- <filename>poky_sdk</filename> directory.
+ <note>
+ 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.
+ </note>
</para>
<para>
@@ -517,159 +564,93 @@
section.
</para>
- <section id='patch-kernel-set-up-the-build-host'>
- <title>Set Up the Build Host</title>
-
- <para>
- Prior to creating any actual patches for your kernel, you
- need to prepare the build host.
- This example builds an extensible SDK.
- Follow these steps:
- <itemizedlist>
- <listitem><para>
- <emphasis>Set Up the Build Environment:</emphasis>
- Be sure you are set up to use BitBake in a shell.
- See the
- "<ulink
url='&YOCTO_DOCS_DEV_URL;#setting-up-the-development-host-to-use-the-yocto-project'>Setting Up the
Development Host to Use the Yocto Project</ulink>"
- section in the Yocto Project Development Manual for information
- on how to get a build host ready that is either a native
- Linux machine or a machine that uses CROPS.
- </para></listitem>
- <listitem><para>
- <emphasis>Clone the <filename>poky</filename> Repository:</emphasis>
- You need to have a local copy of the Yocto Project
- <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>
- (i.e. a local <filename>poky</filename> repository).
- See the
- "<ulink url='&YOCTO_DOCS_DEV_URL;#cloning-the-poky-repository'>Cloning the
<filename>poky</filename> Repository</ulink>"
- and possibly 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 all in the Yocto Project Development Manual for
- information on how to clone the <filename>poky</filename>
- repository and check out the appropriate branch for your work.
- </para></listitem>
- <listitem><para>
- <emphasis>Initialize the Build Environment:</emphasis>
- While in the root directory of the Source Directory (i.e.
- <filename>poky</filename>), run the
- <ulink
url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>
- environment setup script to define the OpenEmbedded
- build environment on your build host.
- <literallayout class='monospaced'>
- $ source &OE_INIT_FILE;
- </literallayout>
- Among other things, the script creates the
- <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>,
- which is <filename>build</filename> in this case
- and is located in the
- <ulink url='&YOCTO_DOCS_REF_URL;#source-directory'>Source Directory</ulink>.
- After the script runs, your current working directory
- is set to the <filename>build</filename> directory.
- <note>
- For information on running a memory-resident
- <ulink url='&YOCTO_DOCS_REF_URL;#usingpoky-components-bitbake'>BitBake</ulink>,
- see the
- <ulink
url='&YOCTO_DOCS_REF_URL;#structure-memres-core-script'><filename>oe-init-build-env-memres</filename></ulink>
- setup script.
- </note>
- </para></listitem>
- </itemizedlist>
- </para>
- </section>
-
- <section id='create-a-layer-for-your-changes'>
- <title>Create a Layer for your Changes</title>
-
- <para>
- The first step is to create a layer so you can isolate your
- changes to the kernel.
- Rather than use the <filename>yocto-layer</filename> script
- to create the layer, this example steps through the process
- by hand.
- If you want information on the script that creates a general
- layer, see the
- "<ulink
url='&YOCTO_DOCS_DEV_URL;#creating-a-general-layer-using-the-yocto-layer-script'>Creating a General Layer
Using the yocto-layer Script</ulink>"
- section in the Yocto Project Development Manual.
- </para>
-
- <para>
- These two commands create a directory you can use for your
- layer:
- <literallayout class='monospaced'>
- $ cd ~/poky
- $ mkdir meta-mylayer
- </literallayout>
- Creating a directory that follows the Yocto Project layer naming
- conventions sets up the layer for your changes.
- The layer is where you place your configuration files, append
- files, and patch files.
- To learn more about creating a layer and filling it with the
- files you need, see the
- "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and
Creating Layers</ulink>"
- section in the Yocto Project Development Manual.
- </para>
- </section>
-
- <section id='finding-the-kernel-source-code'>
- <title>Finding the Kernel Source Code</title>
-
- <para>
- Each time you build a kernel image, the kernel source code
- is fetched and unpacked into the following directory:
+ <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'>
- ${S}/linux
+ $ devtool modify linux-yocto
+ Loading cache: 100% |#######################################################################| Time:
0:00:00
+ Loaded 1300 entries from dependency cache.
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+
+ Summary: There was 1 WARNING message shown.
+ Loading cache: 100% |########################################################################| Time:
0:00:00
+ Loaded 1300 entries from dependency cache.
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+
+ Summary: There was 1 WARNING message shown.
+ NOTE: Executing RunQueue Tasks
+ NOTE: Executing do_fetch...
+ NOTE: Executing do_unpack...
+ NOTE: Tasks Summary: Attempted 2 tasks of which 0 didn't need to be rerun and all succeeded.
+ NOTE: Executing RunQueue Tasks
+ NOTE: Executing do_kernel_checkout...
+ NOTE: Tasks Summary: Attempted 3 tasks of which 2 didn't need to be rerun and all succeeded.
+ NOTE: Patching...
+ NOTE: Executing RunQueue Tasks
+ NOTE: Executing do_validate_branches...
+ NOTE: Executing do_kernel_metadata...
+ NOTE: Executing do_patch...
+ NOTE: Tasks Summary: Attempted 6 tasks of which 3 didn't need to be rerun and all succeeded.
+ NOTE: Generating kernel config
+ NOTE: Executing RunQueue Tasks
+ NOTE: Executing do_kernel_configme...
+ NOTE: Executing do_prepare_recipe_sysroot...
+ NOTE: Executing do_configure...
+ NOTE: Tasks Summary: Attempted 9 tasks of which 6 didn't need to be rerun and all succeeded.
+ NOTE: Copying kernel config to srctree
+ NOTE: Source tree extracted to /home/scottrif/poky_sdk/workspace/sources/linux-yocto
+ NOTE: Recipe linux-yocto now set up to build from /home/scottrif/poky_sdk/workspace/sources/linux-yocto
</literallayout>
- See the "<ulink url='&YOCTO_DOCS_DEV_URL;#finding-the-temporary-source-code'>Finding
Temporary Source Code</ulink>"
- section in the Yocto Project Development Manual and the
- <ulink url='&YOCTO_DOCS_REF_URL;#var-S'><filename>S</filename></ulink>
- variable for more information about where source is kept
- during a build.
- </para>
-
- <para>
- For this example, we are going to patch the
- <filename>init/calibrate.c</filename> file
- by adding some simple console <filename>printk</filename> statements that we can
- see when we boot the image using QEMU.
- </para>
- </section>
-
- <section id='creating-the-patch'>
- <title>Creating the Patch</title>
-
- <para>
- Two methods exist by which you can create the patch:
- <ulink
url='&YOCTO_DOCS_SDK_URL;#using-devtool-in-your-sdk-workflow'><filename>devtool</filename></ulink>
- and
- <ulink url='&YOCTO_DOCS_DEV_URL;#using-a-quilt-workflow'>Quilt</ulink>.
- For kernel patches, the Git workflow is more appropriate.
- This section assumes the Git workflow and shows the steps
- specific to this example.
+ <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/build/tmp/work/qemux86-poky-linux/linux-yocto-${PV}-${PR}/linux
+ $ cd ~/poky_sdk/workspace/sources/linux-yocto
</literallayout>
- Because you are working in an established Git repository,
- you must be in this directory in order to commit your changes
- and create the patch file.
- <note>The <ulink url='&YOCTO_DOCS_REF_URL;#var-PV'><filename>PV</filename></ulink>
and
- <ulink url='&YOCTO_DOCS_REF_URL;#var-PR'><filename>PR</filename></ulink>
variables
- represent the version and revision for the
- <filename>linux-yocto</filename> recipe.
- The <filename>PV</filename> variable includes the Git meta and machine
- hashes, which make the directory name longer than you might
- expect.
- </note></para></listitem>
+ </para></listitem>
<listitem><para>
<emphasis>Edit the source file</emphasis>:
- Edit the <filename>init/calibrate.c</filename> file to have the
- following changes:
+ Edit the <filename>init/calibrate.c</filename> file to have
+ the following changes:
<literallayout class='monospaced'>
void calibrate_delay(void)
{
@@ -687,202 +668,239 @@
.
.
.
- </literallayout></para></listitem>
- <listitem><para><emphasis>Stage and commit your changes</emphasis>:
- These Git commands display the modified file, stage it, and then
- commit the file:
- <literallayout class='monospaced'>
- $ git status
- $ git add init/calibrate.c
- $ git commit -m "calibrate: Add printk example"
- </literallayout></para></listitem>
- <listitem><para><emphasis>Generate the patch file</emphasis>:
- This Git command creates the a patch file named
- <filename>0001-calibrate-Add-printk-example.patch</filename>
- in the current directory.
- <literallayout class='monospaced'>
- $ git format-patch -1
</literallayout>
</para></listitem>
</orderedlist>
- </para>
- </section>
-
- <section id='set-up-your-layer-for-the-build'>
- <title>Set Up Your Layer for the Build</title>
-
- <para>These steps get your layer set up for the build:
+ </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
+ Parsing recipes: 100%
|####################################################################################| Time: 0:00:31
+ Parsing of 831 .bb files complete (0 cached, 831 parsed). 1300 targets, 48 skipped, 0 masked, 0 errors.
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ NOTE: There are 1 recipes to be removed from sysroot qemux86, removing...
+ NOTE: Resolving any missing task queue dependencies
+ Initialising tasks: 100%
|#################################################################################| Time: 0:00:00
+ Checking sstate mirror object availability: 100%
|#########################################################| Time: 0:00:00
+ NOTE: Executing SetScene Tasks
+ NOTE: Executing RunQueue Tasks
+ linux-yocto-4.10.17+git999-r0 do_compile: NOTE: linux-yocto: compiling from external source tree
/home/scottrif/poky_sdk/workspace/sources/linux-yocto
+ NOTE: Tasks Summary: Attempted 471 tasks of which 454 didn't need to be rerun and all succeeded.
+
+ Summary: There was 1 WARNING message shown.
+ </literallayout>
+ </para></listitem>
+<!--
+ <listitem><para>
+
+NOTE: This stuff is how it would have been if a *.wic file was created
+ when the image was built earlier. That is the method used by the
+ example in the wiki (https://wiki.yoctoproject.org/wiki/TipsAndTricks/KernelDevelopmentWithEsdk).
+ I am leaving it here for now.
+
+ <emphasis>Create the Image With the New Kernel:</emphasis>
+ Normally, you would create a new image using the
+ <filename>devtool build-image</filename> command.
+ However, this method can take some time and alters the
+ kernel source folder.
+ A faster option is to use
+ <ulink url='https://linux.die.net/man/8/kpartx'><filename>kpartx</filename></ulink>
+ to splice the new kernel into the image you have already built.
+ <note>
+ You might have to install <filename>kpartx</filename>
+ onto your build host.
+ </note>
+ Follow these steps to create the image with the new kernel:
<orderedlist>
- <listitem><para><emphasis>Create additional structure</emphasis>:
- Create the additional layer structure:
- <literallayout class='monospaced'>
- $ cd ~/poky/meta-mylayer
- $ mkdir conf
- $ mkdir recipes-kernel
- $ mkdir recipes-kernel/linux
- $ mkdir 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
- your patch file.</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 <filename>linux-yocto_3.4.bbappend</filename> file as follows:
+ <listitem><para>
+ <emphasis>Make a Copy of Your Wic File:</emphasis>
+ Create a copy of your Wic from into the
+ <filename>/tmp</filename> directory:
<literallayout class='monospaced'>
- FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
-
- SRC_URI += "file://0001-calibrate-Add-printk-example.patch"
+ $ cp tmp/deploy/images/qemux86/core-image-minimal-qemux86.wic /tmp
</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.
- 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 Manual.
</para></listitem>
<listitem><para>
- <emphasis>Put the patch file in your layer</emphasis>:
- Move the <filename>0001-calibrate-Add-printk-example.patch</filename> file to
- the <filename>meta-mylayer/recipes-kernel/linux/linux-yocto</filename>
- directory.</para></listitem>
- </orderedlist>
- </para>
- </section>
-
- <section id='set-up-for-the-build'>
- <title>Set Up for the Build</title>
-
- <para>
- Do the following to make sure the build parameters are set up for the example.
- Once you set up these build parameters, they do not have to change unless you
- change the target architecture of the machine you are building:
- <itemizedlist>
- <listitem><para><emphasis>Build for the correct target architecture:</emphasis> Your
- selected <ulink
url='&YOCTO_DOCS_REF_URL;#var-MACHINE'><filename>MACHINE</filename></ulink>
- definition within the <filename>local.conf</filename> file in the
- <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>
- specifies the target architecture used when building the Linux kernel.
- By default, <filename>MACHINE</filename> is set to
- <filename>qemux86</filename>, which specifies a 32-bit
- <trademark class='registered'>Intel</trademark> Architecture
- target machine suitable for the QEMU emulator.</para></listitem>
- <listitem><para><emphasis>Identify your <filename>meta-mylayer</filename>
- layer:</emphasis> The
- <ulink url='&YOCTO_DOCS_REF_URL;#var-BBLAYERS'><filename>BBLAYERS</filename></ulink>
- variable in the
- <filename>bblayers.conf</filename> file found in the
- <filename>poky/build/conf</filename> directory needs to have the path to your local
- <filename>meta-mylayer</filename> layer.
- By default, the <filename>BBLAYERS</filename> variable contains paths to
- <filename>meta</filename>, <filename>meta-poky</filename>, and
- <filename>meta-yocto-bsp</filename> in the
- <filename>poky</filename> Git repository.
- Add the path to your <filename>meta-mylayer</filename> location:
+ <emphasis>Create Loopback Devices for Partitions:</emphasis>
+ Next, create loopback devices for each partition in
+ the Wic file.
+ <note>
+ The first unused loopback device is automatically
+ allocated.
+ </note>
+ In this example, the command's output uses a variable
+ "<replaceable>X</replaceable>" to indicate the loopback
+ device.
+ The actual output you get when you run the command lists
+ the actual loopback devices (e.g. "loop0p1", "loop0p2",
+ and "loop0p3"):
<literallayout class='monospaced'>
- BBLAYERS ?= " \
- $HOME/poky/meta \
- $HOME/poky/meta-poky \
- $HOME/poky/meta-yocto-bsp \
- $HOME/poky/meta-mylayer \
- "
- </literallayout></para></listitem>
- </itemizedlist>
- </para>
- </section>
-
- <section id='build-the-modified-qemu-kernel-image'>
- <title>Build the Modified QEMU Kernel Image</title>
-
- <para>
- The following steps build your modified kernel image:
- <orderedlist>
- <listitem><para><emphasis>Be sure your build environment is initialized</emphasis>:
- Your environment should be set up since you previously sourced
- the
- <ulink
url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>
- script.
- If it is not, source the script again from <filename>poky</filename>.
+ $ sudo kpartx -v -a /tmp/core-image-minimal-qemux86.wic
+ add map loop<replaceable>X</replaceable>p1 (253:6): 0 47446 linear /dev/loopX 2048
+ add map loop<replaceable>X</replaceable>p2 (253:7): 0 119356 linear /dev/loopX 51200
+ add map loop<replaceable>X</replaceable>p3 (253:8): 0 90112 linear /dev/loopX 170556
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Mount the First Device:</emphasis>
+ The kernel is in the first device, so mount
+
<filename>/dev/mapper/loop</filename><replaceable>X</replaceable><filename>p1</filename>:
+ <note>
+ Be sure to replace the "<replaceable>X</replaceable>"
+ in "loop<replaceable>X</replaceable>p1" with the
+ automatically allocated loopback device
+ (e.g loop0p1).
+ </note>
<literallayout class='monospaced'>
- $ cd ~/poky
- $ source &OE_INIT_FILE;
+ $ sudo mkdir /mnt/wic-p1
+ $ sudo mount /dev/mapper/loop<replaceable>X</replaceable>p1 /mnt/wic-p1
</literallayout>
</para></listitem>
<listitem><para>
- <emphasis>Clean up</emphasis>:
- Be sure to clean the shared state out by using BitBake
- to run from within the Build Directory the
- <ulink
url='&YOCTO_DOCS_REF_URL;#ref-tasks-cleansstate'><filename>do_cleansstate</filename></ulink>
- task as follows:
+ <emphasis>Copy Over the New Kernel:</emphasis>
+ Now copy over new kernel using the following:
<literallayout class='monospaced'>
- $ bitbake -c cleansstate linux-yocto
- </literallayout></para>
- <para>
- <note>
- Never remove any files by hand from the
- <filename>tmp/deploy</filename>
- directory inside the
- <ulink url='&YOCTO_DOCS_REF_URL;#build-directory'>Build Directory</ulink>.
- Always use the various BitBake clean tasks to
- clear out previous build artifacts.
- For information on the clean tasks, see the
- "<ulink
url='&YOCTO_DOCS_REF_URL;#ref-tasks-clean'><filename>do_clean</filename></ulink>",
- "<ulink
url='&YOCTO_DOCS_REF_URL;#ref-tasks-cleanall'><filename>do_cleanall</filename></ulink>",
- and
- "<ulink
url='&YOCTO_DOCS_REF_URL;#ref-tasks-cleansstate'><filename>do_cleansstate</filename></ulink>"
- sections all in the Yocto Project Reference
- Manual.
- </note>
+ $ sudo cp workspace/sources/linux-yocto/arch/x86/boot/bzImage /mnt/wic-p1
+ </literallayout>
</para></listitem>
<listitem><para>
- <emphasis>Build the image</emphasis>:
- Next, build the kernel image using this command:
+ Finally, unmount the device and use
+ <filename>kpartx</filename> to delete the partition
+ mappings:
+ <note>
+ Replace the "<replaceable>X</replaceable>" in
+ "loop<replaceable>X</replaceable>" with the
+ automatically allocated loopback device from
+ earlier (e.g "loop0").
+ </note>
<literallayout class='monospaced'>
- $ bitbake -k linux-yocto
- </literallayout></para></listitem>
+ $ sudo umount /mnt/wic-p1
+ $ sudo kpartx -d /dev/loop<replaceable>X</replaceable>
+ </literallayout>
+ </para></listitem>
</orderedlist>
- </para>
- </section>
-
- <section id='boot-the-image-and-verify-your-changes'>
- <title>Boot the Image and Verify Your Changes</title>
-
- <para>
- These steps boot the image and allow you to see the changes
+ </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
+ Loading cache: 100% |###########################################################################| Time:
0:00:00
+ Loaded 1299 entries from dependency cache.
+ Parsing recipes: 100% |#########################################################################| Time:
0:00:00
+ Parsing of 831 .bb files complete (830 cached, 1 parsed). 1300 targets, 48 skipped, 0 masked, 0 errors.
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+
+ Summary: There was 1 WARNING message shown.
+ WARNING: Skipping recipe linux-yocto as it doesn't produce a package with the same name
+ WARNING: No recipes in workspace, building image core-image-minimal unmodified
+ Loading cache: 100% |###########################################################################| Time:
0:00:00
+ Loaded 1299 entries from dependency cache.
+ Parsing recipes: 100% |#########################################################################| Time:
0:00:00
+ Parsing of 831 .bb files complete (830 cached, 1 parsed). 1300 targets, 48 skipped, 0 masked, 0 errors.
+ WARNING: No bb files matched BBFILE_PATTERN_my-kernel '^/home/scottrif/poky_sdk/layers/meta-my-kernel/'
+ NOTE: Resolving any missing task queue dependencies
+ Initialising tasks: 100% |######################################################################| Time:
0:00:06
+ Checking sstate mirror object availability: 100% |##############################################| Time:
0:00:00
+ NOTE: Executing SetScene Tasks
+ NOTE: Executing RunQueue Tasks
+ NOTE: Tasks Summary: Attempted 2393 tasks of which 2375 didn't need to be rerun and all succeeded.
+
+ Summary: There was 1 WARNING message shown.
+ NOTE: Successfully built core-image-minimal. You can find output files in
/home/scottrif/poky_sdk/tmp/deploy/images/qemux86
+ </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>:
+ <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>
+ </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.</para></listitem>
+ 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>
- </section>
+ </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 a <filename>.bbappend</filename>:</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-my-kernel</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 /path/to/meta-my-kernel
+ </literallayout>
+ Once the command finishes, the patches and the
+ <filename>.bbappend</filename> file are located in the
+ <filename>~/meta-my-kernel/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>
</section>
<section id='using-an-iterative-development-process'>
@@ -1174,7 +1192,7 @@
are very time consuming.
</para>
- <para>
+ <para role='writernotes'>
Once you are satisfied with your source code modifications,
you can make them permanent by generating patches and
applying them to the
@@ -1183,7 +1201,7 @@
"<link linkend='applying-patches'>Applying Patches</link>"
section.
If you are not familiar with generating patches, refer to the
- "<link linkend='creating-the-patch'>Creating the Patch</link>"
+ "I need a linked section here for the patch stuff"
section.
</para>
</section>
diff --git a/documentation/kernel-dev/kernel-dev-intro.xml b/documentation/kernel-dev/kernel-dev-intro.xml
index a2644aa..ce8e0fc 100644
--- a/documentation/kernel-dev/kernel-dev-intro.xml
+++ b/documentation/kernel-dev/kernel-dev-intro.xml
@@ -108,6 +108,16 @@
"<ulink url='&YOCTO_DOCS_DEV_URL;#cloning-the-poky-repository'>Cloning the <filename>poky</filename>
Repository</ulink>"
section in the Yocto Project Development Manual to set up your
Source Directory.
+ <note>
+ Be sure you check out the appropriate development branch or
+ by tag to get the version of Yocto Project you want.
+ 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 Manual for more
+ information.
+ </note>
</para>
<para>
@@ -156,7 +166,7 @@
building for the QEMU emulator in 32-bit mode.
However, if you are not, you need to set the
<filename>MACHINE</filename> variable appropriately in
- your <filename>local.conf</filename> file found in the
+ 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>
@@ -208,6 +218,7 @@
Use BitBake to build the extensible SDK specifically for
the Minnowboard:
<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
@@ -290,12 +301,9 @@
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.
- Use a command similar to the following command to flash
- the image:
- <literallayout class='monospaced'>
- $ sudo dd
if=tmp/deploy/images/<replaceable>architecture</replaceable>/core-image-minimal-<replaceable>architecture</replaceable>.wic
of=/dev/sdd bs=1MB
- $ sync
- </literallayout>
+ 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>
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