diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml
index 0c2e60f006..f82d37e1dc 100644
--- a/documentation/dev-manual/dev-manual-common-tasks.xml
+++ b/documentation/dev-manual/dev-manual-common-tasks.xml
@@ -442,54 +442,65 @@
existing Yocto Project layers (i.e. the layer is compatible
with the Yocto Project).
Ensuring compatibility makes the layer easy to be consumed
- by others in the Yocto Project community and allows you
- permission to use the Yocto Project Compatibility logo.
-
-
-
- Version 1.0 of the Yocto Project Compatibility Program has
- been in existence for a number of releases.
- This version of the program consists of the layer application
- process that requests permission to use the Yocto Project
- Compatibility logo for your layer and application.
- You can find version 1.0 of the form at
- .
- To be granted permission to use the logo, you need to be able
- to answer "Yes" to the questions or have an acceptable
- explanation for any questions answered "No".
-
-
-
- A second version (2.0) of the Yocto Project Compatibility
- Program is currently under development.
- Included as part of version 2.0 (and currently available) is
- the yocto-compat-layer.py script.
- When run against a layer, this script tests the layer against
- tighter constraints based on experiences of how layers have
- worked in the real world and where pitfalls have been found.
-
-
-
- Part of the 2.0 version of the program that is not currently
- available but is in development is an updated compatibility
- application form.
- This updated form, among other questions, specifically
- asks if your layer has passed the test using the
- yocto-compat-layer.py script.
- Tip
- Even though the updated application form is currently
- unavailable for version 2.0 of the Yocto Project
- Compatibility Program, the
- yocto-compat-layer.py script is
- available in OE-Core.
- You can use the script to assess the status of your
- layers in advance of the 2.0 release of the program.
+ by others in the Yocto Project community and could allow you
+ permission to use the Yocto Project Compatibility Logo.
+
+ Only Yocto Project member organizations are permitted to
+ use the Yocto Project Compatibility Logo.
+ The logo is not available for general use.
+ For information on how to become a Yocto Project member
+ organization, see the
+ Member Organizations
+ page of the Yocto Project website.
+
+ The Yocto Project Compatibility Program consists of a layer
+ application process that requests permission to use the Yocto
+ Project Compatibility Logo for your layer and application.
+ The process consists of two parts:
+
+
+ Successfully passing a script
+ (yocto-compat-layer.py) that
+ when run against your layer, tests it against
+ constraints based on experiences of how layers have
+ worked in the real world and where pitfalls have been
+ found.
+ Getting a "PASS" result from the script is required for
+ successful compatibility registration.
+
+
+ Completion of an application acceptance form, which
+ you can find at
+ .
+
+
+
+
+
+ To be granted permission to use the logo, you need to satisfy
+ the following:
+
+
+ Be able to check the box indicating that you
+ got a "PASS" when running the script against your
+ layer.
+
+
+ Answer "Yes" to the questions on the form or have an
+ acceptable explanation for any questions answered "No".
+
+
+ You need to be a Yocto Project Member Organization.
+
+
+
+
The remainder of this section presents information on the
- version 1.0 registration form and on the
+ registration form and on the
yocto-compat-layer.py script.
@@ -497,10 +508,10 @@
Yocto Project Compatibility Program Application
- Use the 1.0 version of the form to apply for your
- layer's compatibility approval.
+ Use the form to apply for your layer's compatibility
+ approval.
Upon successful application, you can use the Yocto
- Project Compatibility logo with your layer and the
+ Project Compatibility Logo with your layer and the
application that uses your layer.
@@ -542,22 +553,14 @@
<filename>yocto-compat-layer.py</filename> Script
- The yocto-compat-layer.py script,
- which is currently available, provides you a way to
- assess how compatible your layer is with the Yocto
- Project.
+ The yocto-compat-layer.py script
+ provides you a way to assess how compatible your layer is
+ with the Yocto Project.
You should run this script prior to using the form to
apply for compatibility as described in the previous
section.
-
- Because the script is part of the 2.0 release of the
- Yocto Project Compatibility Program, you are not
- required to successfully run your layer against it
- in order to be granted compatibility status.
- However, it is a good idea as it promotes
- well-behaved layers and gives you an idea of where your
- layer stands regarding compatibility.
-
+ You need to achieve a "PASS" result in order to have
+ your application form successfully processed.
@@ -6142,479 +6145,6 @@ Some notes from Cal:
-
- Configuring the Kernel
-
-
- Configuring the Yocto Project kernel consists of making sure the
- .config file has all the right information
- in it for the image you are building.
- You can use the menuconfig tool and
- configuration fragments to make sure your
- .config file is just how you need it.
- You can also save known configurations in a
- defconfig file that the build system can use
- for kernel configuration.
-
-
-
- This section describes how to use menuconfig,
- create and use configuration fragments, and how to interactively
- modify your .config file to create the
- leanest kernel configuration file possible.
-
-
-
- For more information on kernel configuration, see the
- "Changing the Configuration"
- section in the Yocto Project Linux Kernel Development Manual.
-
-
-
- Using <filename>menuconfig</filename>
-
-
- The easiest way to define kernel configurations is to set them through the
- menuconfig tool.
- This tool provides an interactive method with which
- to set kernel configurations.
- For general information on menuconfig, see
- .
-
-
-
- To use the menuconfig tool in the Yocto Project development
- environment, you must launch it using BitBake.
- Thus, the environment must be set up using the
- &OE_INIT_FILE;
- script found in the
- Build Directory.
- You must also be sure of the state of your build in the
- Source Directory.
- The following commands run menuconfig
- assuming the Source Directory's top-level folder is
- ~/poky:
-
- $ cd poky
- $ source oe-init-build-env
- $ bitbake linux-yocto -c kernel_configme -f
- $ bitbake linux-yocto -c menuconfig
-
- Once menuconfig comes up, its standard
- interface allows you to interactively examine and configure
- all the kernel configuration parameters.
- After making your changes, simply exit the tool and save your
- changes to create an updated version of the
- .config configuration file.
-
-
-
- Consider an example that configures the linux-yocto-3.14
- kernel.
- The OpenEmbedded build system recognizes this kernel as
- linux-yocto.
- Thus, the following commands from the shell in which you previously sourced the
- environment initialization script cleans the shared state cache and the
- WORKDIR
- directory and then runs menuconfig:
-
- $ bitbake linux-yocto -c menuconfig
-
-
-
-
- Once menuconfig launches, use the interface
- to navigate through the selections to find the configuration settings in
- which you are interested.
- For example, consider the CONFIG_SMP configuration setting.
- You can find it at Processor Type and Features under
- the configuration selection Symmetric Multi-processing Support.
- After highlighting the selection, use the arrow keys to select or deselect
- the setting.
- When you are finished with all your selections, exit out and save them.
-
-
-
- Saving the selections updates the .config configuration file.
- This is the file that the OpenEmbedded build system uses to configure the
- kernel during the build.
- You can find and examine this file in the Build Directory in
- tmp/work/.
- The actual .config is located in the area where the
- specific kernel is built.
- For example, if you were building a Linux Yocto kernel based on the
- Linux 3.14 kernel and you were building a QEMU image targeted for
- x86 architecture, the
- .config file would be located here:
-
- poky/build/tmp/work/qemux86-poky-linux/linux-yocto-3.14.11+git1+84f...
- ...656ed30-r1/linux-qemux86-standard-build
-
-
- The previous example directory is artificially split and many of the characters
- in the actual filename are omitted in order to make it more readable.
- Also, depending on the kernel you are using, the exact pathname
- for linux-yocto-3.14... might differ.
-
-
-
-
- Within the .config file, you can see the kernel settings.
- For example, the following entry shows that symmetric multi-processor support
- is not set:
-
- # CONFIG_SMP is not set
-
-
-
-
- A good method to isolate changed configurations is to use a combination of the
- menuconfig tool and simple shell commands.
- Before changing configurations with menuconfig, copy the
- existing .config and rename it to something else,
- use menuconfig to make
- as many changes as you want and save them, then compare the renamed configuration
- file against the newly created file.
- You can use the resulting differences as your base to create configuration fragments
- to permanently save in your kernel layer.
-
- Be sure to make a copy of the .config and don't just
- rename it.
- The build system needs an existing .config
- from which to work.
-
-
-
-
-
- Creating a <filename>defconfig</filename> File
-
-
- A defconfig file is simply a
- .config renamed to "defconfig".
- You can use a defconfig file
- to retain a known set of kernel configurations from which the
- OpenEmbedded build system can draw to create the final
- .config file.
-
- Out-of-the-box, the Yocto Project never ships a
- defconfig or
- .config file.
- The OpenEmbedded build system creates the final
- .config file used to configure the
- kernel.
-
-
-
-
- To create a defconfig, start with a
- complete, working Linux kernel .config
- file.
- Copy that file to the appropriate
- ${PN}
- directory in your layer's
- recipes-kernel/linux directory, and rename
- the copied file to "defconfig".
- Then, add the following lines to the linux-yocto
- .bbappend file in your layer:
-
- FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
- SRC_URI += "file://defconfig"
-
- The
- SRC_URI
- tells the build system how to search for the file, while the
- FILESEXTRAPATHS
- extends the
- FILESPATH
- variable (search directories) to include the
- ${PN} directory you created to hold the
- configuration changes.
-
- The build system applies the configurations from the
- defconfig file before applying any
- subsequent configuration fragments.
- The final kernel configuration is a combination of the
- configurations in the defconfig
- file and any configuration fragments you provide.
- You need to realize that if you have any configuration
- fragments, the build system applies these on top of and
- after applying the existing defconfig file configurations.
-
- For more information on configuring the kernel, see the
- "Changing the Configuration"
- and
- "Generating Configuration Files"
- sections, both in the Yocto Project Linux Kernel Development
- Manual.
-
-
-
-
- Creating Configuration Fragments
-
-
- Configuration fragments are simply kernel options that appear in a file
- placed where the OpenEmbedded build system can find and apply them.
- Syntactically, the configuration statement is identical to what would appear
- in the .config file, which is in the
- Build Directory:
-
- tmp/work/arch-poky-linux/linux-yocto-release_specific_string/linux-arch-build_type
-
-
-
-
- It is simple to create a configuration fragment.
- For example, issuing the following from the shell creates a configuration fragment
- file named my_smp.cfg that enables multi-processor support
- within the kernel:
-
- $ echo "CONFIG_SMP=y" >> my_smp.cfg
-
-
- All configuration fragment files must use the
- .cfg extension in order for the
- OpenEmbedded build system to recognize them as a
- configuration fragment.
-
-
-
-
- Where do you put your configuration fragment files?
- You can place these files in the same area pointed to by
- SRC_URI.
- The OpenEmbedded build system picks up the configuration and
- adds it to the kernel's configuration.
- For example, suppose you had a set of configuration options
- in a file called myconfig.cfg.
- If you put that file inside a directory named
- linux-yocto that resides in the same
- directory as the kernel's append file and then add a
- SRC_URI statement such as the following
- to the kernel's append file, those configuration options
- will be picked up and applied when the kernel is built.
-
- SRC_URI += "file://myconfig.cfg"
-
-
-
-
- As mentioned earlier, you can group related configurations into multiple files and
- name them all in the SRC_URI statement as well.
- For example, you could group separate configurations specifically for Ethernet and graphics
- into their own files and add those by using a SRC_URI statement like the
- following in your append file:
-
- SRC_URI += "file://myconfig.cfg \
- file://eth.cfg \
- file://gfx.cfg"
-
-
-
-
-
- Fine-Tuning the Kernel Configuration File
-
-
- You can make sure the .config file is as lean or efficient as
- possible by reading the output of the kernel configuration fragment audit,
- noting any issues, making changes to correct the issues, and then repeating.
-
-
-
- As part of the kernel build process, the
- do_kernel_configcheck task runs.
- This task validates the kernel configuration by checking the final
- .config file against the input files.
- During the check, the task produces warning messages for the following
- issues:
-
- Requested options that did not make the final
- .config file.
- Configuration items that appear twice in the same
- configuration fragment.
- Configuration items tagged as "required" that were overridden.
-
- A board overrides a non-board specific option.
- Listed options not valid for the kernel being processed.
- In other words, the option does not appear anywhere.
-
-
- The do_kernel_configcheck task can
- also optionally report if an option is overridden during
- processing.
-
-
-
-
- For each output warning, a message points to the file
- that contains a list of the options and a pointer to the
- configuration fragment that defines them.
- Collectively, the files are the key to streamlining the
- configuration.
-
-
-
- To streamline the configuration, do the following:
-
- Start with a full configuration that you
- know works - it builds and boots successfully.
- This configuration file will be your baseline.
-
- Separately run the
- do_kernel_configme and
- do_kernel_configcheck tasks.
-
- Take the resulting list of files from the
- do_kernel_configcheck task
- warnings and do the following:
-
-
- Drop values that are redefined in the fragment
- but do not change the final
- .config file.
-
-
- Analyze and potentially drop values from the
- .config file that override
- required configurations.
-
-
- Analyze and potentially remove non-board
- specific options.
-
-
- Remove repeated and invalid options.
-
-
-
- After you have worked through the output of the kernel
- configuration audit, you can re-run the
- do_kernel_configme and
- do_kernel_configcheck tasks to
- see the results of your changes.
- If you have more issues, you can deal with them as
- described in the previous step.
-
-
-
-
-
- Iteratively working through steps two through four eventually yields
- a minimal, streamlined configuration file.
- Once you have the best .config, you can build the Linux
- Yocto kernel.
-
-
-
-
- Determining Hardware and Non-Hardware Features for the Kernel Configuration Audit Phase
-
-
- This section describes part of the kernel configuration audit
- phase that most developers can ignore.
- During this part of the audit phase, the contents of the final
- .config file are compared against the
- fragments specified by the system.
- These fragments can be system fragments, distro fragments,
- or user specified configuration elements.
- Regardless of their origin, the OpenEmbedded build system
- warns the user if a specific option is not included in the
- final kernel configuration.
-
-
-
- In order to not overwhelm the user with configuration warnings,
- by default the system only reports on missing "hardware"
- options because a missing hardware option could mean a boot
- failure or that important hardware is not available.
-
-
-
- To determine whether or not a given option is "hardware" or
- "non-hardware", the kernel Metadata contains files that
- classify individual or groups of options as either hardware
- or non-hardware.
- To better show this, consider a situation where the
- Yocto Project kernel cache contains the following files:
-
- kernel-cache/features/drm-psb/hardware.cfg
- kernel-cache/features/kgdb/hardware.cfg
- kernel-cache/ktypes/base/hardware.cfg
- kernel-cache/bsp/mti-malta32/hardware.cfg
- kernel-cache/bsp/fsl-mpc8315e-rdb/hardware.cfg
- kernel-cache/bsp/qemu-ppc32/hardware.cfg
- kernel-cache/bsp/qemuarma9/hardware.cfg
- kernel-cache/bsp/mti-malta64/hardware.cfg
- kernel-cache/bsp/arm-versatile-926ejs/hardware.cfg
- kernel-cache/bsp/common-pc/hardware.cfg
- kernel-cache/bsp/common-pc-64/hardware.cfg
- kernel-cache/features/rfkill/non-hardware.cfg
- kernel-cache/ktypes/base/non-hardware.cfg
- kernel-cache/features/aufs/non-hardware.kcf
- kernel-cache/features/ocf/non-hardware.kcf
- kernel-cache/ktypes/base/non-hardware.kcf
- kernel-cache/ktypes/base/hardware.kcf
- kernel-cache/bsp/qemu-ppc32/hardware.kcf
-
- The following list provides explanations for the various
- files:
-
- hardware.kcf:
- Specifies a list of kernel Kconfig files that contain
- hardware options only.
-
- non-hardware.kcf:
- Specifies a list of kernel Kconfig files that contain
- non-hardware options only.
-
- hardware.cfg:
- Specifies a list of kernel
- CONFIG_ options that are hardware,
- regardless of whether or not they are within a Kconfig
- file specified by a hardware or non-hardware
- Kconfig file (i.e. hardware.kcf or
- non-hardware.kcf).
-
- non-hardware.cfg:
- Specifies a list of kernel
- CONFIG_ options that are
- not hardware, regardless of whether or not they are
- within a Kconfig file specified by a hardware or
- non-hardware Kconfig file (i.e.
- hardware.kcf or
- non-hardware.kcf).
-
-
- Here is a specific example using the
- kernel-cache/bsp/mti-malta32/hardware.cfg:
-
- CONFIG_SERIAL_8250
- CONFIG_SERIAL_8250_CONSOLE
- CONFIG_SERIAL_8250_NR_UARTS
- CONFIG_SERIAL_8250_PCI
- CONFIG_SERIAL_CORE
- CONFIG_SERIAL_CORE_CONSOLE
- CONFIG_VGA_ARB
-
- The kernel configuration audit automatically detects these
- files (hence the names must be exactly the ones discussed here),
- and uses them as inputs when generating warnings about the
- final .config file.
-
-
-
- A user-specified kernel Metadata repository, or recipe space
- feature, can use these same files to classify options that are
- found within its .cfg files as hardware
- or non-hardware, to prevent the OpenEmbedded build system from
- producing an error or warning when an option is not in the
- final .config file.
-
-
-
-
Making Images More Secure
@@ -7243,8 +6773,11 @@ Some notes from Cal:
see the
"Generating Configuration Files"
section of the Yocto Project Linux Kernel Development
- Manual and the "Creating Configuration Fragments"
- section, which is in this manual.
+ Manual and the
+ "Creating Configuration Fragments"
+ section in the Yocto Project Linux Kernel Development
+ Manual.
+
bitbake -u taskexp -g bitbake_target:
Using the BitBake command with these options brings up
a Dependency Explorer from which you can view file
diff --git a/documentation/kernel-dev/kernel-dev-advanced.xml b/documentation/kernel-dev/kernel-dev-advanced.xml
index 0394e08444..a6f01a8e2a 100644
--- a/documentation/kernel-dev/kernel-dev-advanced.xml
+++ b/documentation/kernel-dev/kernel-dev-advanced.xml
@@ -318,10 +318,10 @@
CONFIG_NR_CPUS=64
You can find information on configuration fragment files in the
- "Creating Configuration Fragments"
- section of the Yocto Project Development Manual and in
+ "Creating Configuration Fragments"
+ section and in
the "Generating Configuration Files"
- section earlier in this manual.
+ section.
diff --git a/documentation/kernel-dev/kernel-dev-common.xml b/documentation/kernel-dev/kernel-dev-common.xml
index 28bedd1785..7f61b434cd 100644
--- a/documentation/kernel-dev/kernel-dev-common.xml
+++ b/documentation/kernel-dev/kernel-dev-common.xml
@@ -900,8 +900,8 @@
For a detailed example showing how to configure the kernel,
see the
- "Configuring the Kernel"
- section in the Yocto Project Development Manual.
+ "Configuring the Kernel"
+ section.
@@ -1445,6 +1445,522 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Configuring the Kernel
+
+
+ Configuring the Yocto Project kernel consists of making sure the
+ .config file has all the right information
+ in it for the image you are building.
+ You can use the menuconfig tool and
+ configuration fragments to make sure your
+ .config file is just how you need it.
+ You can also save known configurations in a
+ defconfig file that the build system can use
+ for kernel configuration.
+
+
+
+ This section describes how to use menuconfig,
+ create and use configuration fragments, and how to interactively
+ modify your .config file to create the
+ leanest kernel configuration file possible.
+
+
+
+ For more information on kernel configuration, see the
+ "Changing the Configuration"
+ section.
+
+
+
+ Using <filename>menuconfig</filename>
+
+
+ The easiest way to define kernel configurations is to set them through the
+ menuconfig tool.
+ This tool provides an interactive method with which
+ to set kernel configurations.
+ For general information on menuconfig, see
+ .
+
+
+
+ To use the menuconfig tool in the Yocto Project development
+ environment, you must launch it using BitBake.
+ Thus, the environment must be set up using the
+ &OE_INIT_FILE;
+ script found in the
+ Build Directory.
+ You must also be sure of the state of your build in the
+ Source Directory.
+ The following commands run menuconfig
+ assuming the Source Directory's top-level folder is
+ ~/poky:
+
+ $ cd poky
+ $ source oe-init-build-env
+ $ bitbake linux-yocto -c kernel_configme -f
+ $ bitbake linux-yocto -c menuconfig
+
+ Once menuconfig comes up, its standard
+ interface allows you to interactively examine and configure
+ all the kernel configuration parameters.
+ After making your changes, simply exit the tool and save your
+ changes to create an updated version of the
+ .config configuration file.
+
+
+
+ Consider an example that configures the linux-yocto-3.14
+ kernel.
+ The OpenEmbedded build system recognizes this kernel as
+ linux-yocto.
+ Thus, the following commands from the shell in which you previously sourced the
+ environment initialization script cleans the shared state cache and the
+ WORKDIR
+ directory and then runs menuconfig:
+
+ $ bitbake linux-yocto -c menuconfig
+
+
+
+
+ Once menuconfig launches, use the interface
+ to navigate through the selections to find the configuration settings in
+ which you are interested.
+ For example, consider the CONFIG_SMP configuration setting.
+ You can find it at Processor Type and Features under
+ the configuration selection Symmetric Multi-processing Support.
+ After highlighting the selection, use the arrow keys to select or deselect
+ the setting.
+ When you are finished with all your selections, exit out and save them.
+
+
+
+ Saving the selections updates the .config configuration file.
+ This is the file that the OpenEmbedded build system uses to configure the
+ kernel during the build.
+ You can find and examine this file in the Build Directory in
+ tmp/work/.
+ The actual .config is located in the area where the
+ specific kernel is built.
+ For example, if you were building a Linux Yocto kernel based on the
+ Linux 3.14 kernel and you were building a QEMU image targeted for
+ x86 architecture, the
+ .config file would be located here:
+
+ poky/build/tmp/work/qemux86-poky-linux/linux-yocto-3.14.11+git1+84f...
+ ...656ed30-r1/linux-qemux86-standard-build
+
+
+ The previous example directory is artificially split and many of the characters
+ in the actual filename are omitted in order to make it more readable.
+ Also, depending on the kernel you are using, the exact pathname
+ for linux-yocto-3.14... might differ.
+
+
+
+
+ Within the .config file, you can see the kernel settings.
+ For example, the following entry shows that symmetric multi-processor support
+ is not set:
+
+ # CONFIG_SMP is not set
+
+
+
+
+ A good method to isolate changed configurations is to use a combination of the
+ menuconfig tool and simple shell commands.
+ Before changing configurations with menuconfig, copy the
+ existing .config and rename it to something else,
+ use menuconfig to make
+ as many changes as you want and save them, then compare the renamed configuration
+ file against the newly created file.
+ You can use the resulting differences as your base to create configuration fragments
+ to permanently save in your kernel layer.
+
+ Be sure to make a copy of the .config and don't just
+ rename it.
+ The build system needs an existing .config
+ from which to work.
+
+
+
+
+
+ Creating a <filename>defconfig</filename> File
+
+
+ A defconfig file is simply a
+ .config renamed to "defconfig".
+ You can use a defconfig file
+ to retain a known set of kernel configurations from which the
+ OpenEmbedded build system can draw to create the final
+ .config file.
+
+ Out-of-the-box, the Yocto Project never ships a
+ defconfig or
+ .config file.
+ The OpenEmbedded build system creates the final
+ .config file used to configure the
+ kernel.
+
+
+
+
+ To create a defconfig, start with a
+ complete, working Linux kernel .config
+ file.
+ Copy that file to the appropriate
+ ${PN}
+ directory in your layer's
+ recipes-kernel/linux directory, and rename
+ the copied file to "defconfig".
+ Then, add the following lines to the linux-yocto
+ .bbappend file in your layer:
+
+ FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+ SRC_URI += "file://defconfig"
+
+ The
+ SRC_URI
+ tells the build system how to search for the file, while the
+ FILESEXTRAPATHS
+ extends the
+ FILESPATH
+ variable (search directories) to include the
+ ${PN} directory you created to hold the
+ configuration changes.
+
+ The build system applies the configurations from the
+ defconfig file before applying any
+ subsequent configuration fragments.
+ The final kernel configuration is a combination of the
+ configurations in the defconfig
+ file and any configuration fragments you provide.
+ You need to realize that if you have any configuration
+ fragments, the build system applies these on top of and
+ after applying the existing defconfig file configurations.
+
+ For more information on configuring the kernel, see the
+ "Changing the Configuration"
+ and
+ "Generating Configuration Files"
+ sections, both in the Yocto Project Linux Kernel Development
+ Manual.
+
+
+
+
+ Creating Configuration Fragments
+
+
+ Configuration fragments are simply kernel options that appear in a file
+ placed where the OpenEmbedded build system can find and apply them.
+ Syntactically, the configuration statement is identical to what would appear
+ in the .config file, which is in the
+ Build Directory:
+
+ tmp/work/arch-poky-linux/linux-yocto-release_specific_string/linux-arch-build_type
+
+
+
+
+ It is simple to create a configuration fragment.
+ For example, issuing the following from the shell creates a configuration fragment
+ file named my_smp.cfg that enables multi-processor support
+ within the kernel:
+
+ $ echo "CONFIG_SMP=y" >> my_smp.cfg
+
+
+ All configuration fragment files must use the
+ .cfg extension in order for the
+ OpenEmbedded build system to recognize them as a
+ configuration fragment.
+
+
+
+
+ Where do you put your configuration fragment files?
+ You can place these files in the same area pointed to by
+ SRC_URI.
+ The OpenEmbedded build system picks up the configuration and
+ adds it to the kernel's configuration.
+ For example, suppose you had a set of configuration options
+ in a file called myconfig.cfg.
+ If you put that file inside a directory named
+ linux-yocto that resides in the same
+ directory as the kernel's append file and then add a
+ SRC_URI statement such as the following
+ to the kernel's append file, those configuration options
+ will be picked up and applied when the kernel is built.
+
+ SRC_URI += "file://myconfig.cfg"
+
+
+
+
+ As mentioned earlier, you can group related configurations into multiple files and
+ name them all in the SRC_URI statement as well.
+ For example, you could group separate configurations specifically for Ethernet and graphics
+ into their own files and add those by using a SRC_URI statement like the
+ following in your append file:
+
+ SRC_URI += "file://myconfig.cfg \
+ file://eth.cfg \
+ file://gfx.cfg"
+
+
+
+
+
+ Fine-Tuning the Kernel Configuration File
+
+
+ You can make sure the .config file is as lean or efficient as
+ possible by reading the output of the kernel configuration fragment audit,
+ noting any issues, making changes to correct the issues, and then repeating.
+
+
+
+ As part of the kernel build process, the
+ do_kernel_configcheck task runs.
+ This task validates the kernel configuration by checking the final
+ .config file against the input files.
+ During the check, the task produces warning messages for the following
+ issues:
+
+ Requested options that did not make the final
+ .config file.
+ Configuration items that appear twice in the same
+ configuration fragment.
+ Configuration items tagged as "required" that were overridden.
+
+ A board overrides a non-board specific option.
+ Listed options not valid for the kernel being processed.
+ In other words, the option does not appear anywhere.
+
+
+ The do_kernel_configcheck task can
+ also optionally report if an option is overridden during
+ processing.
+
+
+
+
+ For each output warning, a message points to the file
+ that contains a list of the options and a pointer to the
+ configuration fragment that defines them.
+ Collectively, the files are the key to streamlining the
+ configuration.
+
+
+
+ To streamline the configuration, do the following:
+
+ Start with a full configuration that you
+ know works - it builds and boots successfully.
+ This configuration file will be your baseline.
+
+ Separately run the
+ do_kernel_configme and
+ do_kernel_configcheck tasks.
+
+ Take the resulting list of files from the
+ do_kernel_configcheck task
+ warnings and do the following:
+
+
+ Drop values that are redefined in the fragment
+ but do not change the final
+ .config file.
+
+
+ Analyze and potentially drop values from the
+ .config file that override
+ required configurations.
+
+
+ Analyze and potentially remove non-board
+ specific options.
+
+
+ Remove repeated and invalid options.
+
+
+
+ After you have worked through the output of the kernel
+ configuration audit, you can re-run the
+ do_kernel_configme and
+ do_kernel_configcheck tasks to
+ see the results of your changes.
+ If you have more issues, you can deal with them as
+ described in the previous step.
+
+
+
+
+
+ Iteratively working through steps two through four eventually yields
+ a minimal, streamlined configuration file.
+ Once you have the best .config, you can build the Linux
+ Yocto kernel.
+
+
+
+
+ Determining Hardware and Non-Hardware Features for the Kernel Configuration Audit Phase
+
+
+ This section describes part of the kernel configuration audit
+ phase that most developers can ignore.
+ During this part of the audit phase, the contents of the final
+ .config file are compared against the
+ fragments specified by the system.
+ These fragments can be system fragments, distro fragments,
+ or user specified configuration elements.
+ Regardless of their origin, the OpenEmbedded build system
+ warns the user if a specific option is not included in the
+ final kernel configuration.
+
+
+
+ In order to not overwhelm the user with configuration warnings,
+ by default the system only reports on missing "hardware"
+ options because a missing hardware option could mean a boot
+ failure or that important hardware is not available.
+
+
+
+ To determine whether or not a given option is "hardware" or
+ "non-hardware", the kernel Metadata contains files that
+ classify individual or groups of options as either hardware
+ or non-hardware.
+ To better show this, consider a situation where the
+ Yocto Project kernel cache contains the following files:
+
+ kernel-cache/features/drm-psb/hardware.cfg
+ kernel-cache/features/kgdb/hardware.cfg
+ kernel-cache/ktypes/base/hardware.cfg
+ kernel-cache/bsp/mti-malta32/hardware.cfg
+ kernel-cache/bsp/fsl-mpc8315e-rdb/hardware.cfg
+ kernel-cache/bsp/qemu-ppc32/hardware.cfg
+ kernel-cache/bsp/qemuarma9/hardware.cfg
+ kernel-cache/bsp/mti-malta64/hardware.cfg
+ kernel-cache/bsp/arm-versatile-926ejs/hardware.cfg
+ kernel-cache/bsp/common-pc/hardware.cfg
+ kernel-cache/bsp/common-pc-64/hardware.cfg
+ kernel-cache/features/rfkill/non-hardware.cfg
+ kernel-cache/ktypes/base/non-hardware.cfg
+ kernel-cache/features/aufs/non-hardware.kcf
+ kernel-cache/features/ocf/non-hardware.kcf
+ kernel-cache/ktypes/base/non-hardware.kcf
+ kernel-cache/ktypes/base/hardware.kcf
+ kernel-cache/bsp/qemu-ppc32/hardware.kcf
+
+ The following list provides explanations for the various
+ files:
+
+ hardware.kcf:
+ Specifies a list of kernel Kconfig files that contain
+ hardware options only.
+
+ non-hardware.kcf:
+ Specifies a list of kernel Kconfig files that contain
+ non-hardware options only.
+
+ hardware.cfg:
+ Specifies a list of kernel
+ CONFIG_ options that are hardware,
+ regardless of whether or not they are within a Kconfig
+ file specified by a hardware or non-hardware
+ Kconfig file (i.e. hardware.kcf or
+ non-hardware.kcf).
+
+ non-hardware.cfg:
+ Specifies a list of kernel
+ CONFIG_ options that are
+ not hardware, regardless of whether or not they are
+ within a Kconfig file specified by a hardware or
+ non-hardware Kconfig file (i.e.
+ hardware.kcf or
+ non-hardware.kcf).
+
+
+ Here is a specific example using the
+ kernel-cache/bsp/mti-malta32/hardware.cfg:
+
+ CONFIG_SERIAL_8250
+ CONFIG_SERIAL_8250_CONSOLE
+ CONFIG_SERIAL_8250_NR_UARTS
+ CONFIG_SERIAL_8250_PCI
+ CONFIG_SERIAL_CORE
+ CONFIG_SERIAL_CORE_CONSOLE
+ CONFIG_VGA_ARB
+
+ The kernel configuration audit automatically detects these
+ files (hence the names must be exactly the ones discussed here),
+ and uses them as inputs when generating warnings about the
+ final .config file.
+
+
+
+ A user-specified kernel Metadata repository, or recipe space
+ feature, can use these same files to classify options that are
+ found within its .cfg files as hardware
+ or non-hardware, to prevent the OpenEmbedded build system from
+ producing an error or warning when an option is not in the
+ final .config file.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Using an Iterative Development Process
@@ -1538,8 +2054,8 @@
"Changing the Configuration" section.
For more information on the .config file,
see the
- "Using menuconfig"
- section in the Yocto Project Development Manual.
+ "Using menuconfig"
+ section.
You can determine what a variable expands to by looking
at the output of the bitbake -e
@@ -1650,8 +2166,8 @@
For more information on how to use the
menuconfig tool, see the
- "Using menuconfig"
- section in the Yocto Project Development Manual.
+ "Using menuconfig"
+ section.
diff --git a/documentation/kernel-dev/kernel-dev-intro.xml b/documentation/kernel-dev/kernel-dev-intro.xml
index b2fe19c175..174ab93ab0 100644
--- a/documentation/kernel-dev/kernel-dev-intro.xml
+++ b/documentation/kernel-dev/kernel-dev-intro.xml
@@ -231,7 +231,7 @@
and you have saved them, you can directly compare the
resulting .config file against an
existing original and gather those changes into a
- configuration fragment file
+ configuration fragment file
to be referenced from within the kernel's
.bbappend file.
diff --git a/documentation/ref-manual/ref-tasks.xml b/documentation/ref-manual/ref-tasks.xml
index 2d23bbaabf..e145518989 100644
--- a/documentation/ref-manual/ref-tasks.xml
+++ b/documentation/ref-manual/ref-tasks.xml
@@ -960,8 +960,8 @@
section in the Yocto Project Linux Kernel Development Manual
for more information on this configuration tool.
You can also reference the
- "Using menuconfig"
- section in the Yocto Project Development Manual.
+ "Using menuconfig"
+ section in the Yocto Project Linux Kernel Development Manual.
@@ -988,8 +988,8 @@
Runs make menuconfig for the kernel.
For information on menuconfig, see the
- "Using menuconfig"
- section in the Yocto Project Development Manual.
+ "Using menuconfig"
+ section in the Yocto Project Linux Kernel Development Manual.