diff options
Diffstat (limited to 'documentation/kernel-dev')
| -rw-r--r-- | documentation/kernel-dev/advanced.rst | 49 | ||||
| -rw-r--r-- | documentation/kernel-dev/common.rst | 316 | ||||
| -rw-r--r-- | documentation/kernel-dev/concepts-appx.rst | 3 | ||||
| -rw-r--r-- | documentation/kernel-dev/faq.rst | 4 | ||||
| -rw-r--r-- | documentation/kernel-dev/intro.rst | 16 | ||||
| -rw-r--r-- | documentation/kernel-dev/maint-appx.rst | 21 |
6 files changed, 185 insertions, 224 deletions
diff --git a/documentation/kernel-dev/advanced.rst b/documentation/kernel-dev/advanced.rst index b16b3e0517..4c463503f6 100644 --- a/documentation/kernel-dev/advanced.rst +++ b/documentation/kernel-dev/advanced.rst @@ -69,8 +69,7 @@ to indicate the branch. You can use the :term:`KBRANCH` value to define an alternate branch typically with a machine override as shown here from the ``meta-yocto-bsp`` layer:: - KBRANCH:edgerouter = "standard/edgerouter" - + KBRANCH:beaglebone-yocto = "standard/beaglebone" The linux-yocto style recipes can optionally define the following variables: @@ -304,8 +303,8 @@ The following listings show the ``build.scc`` file and part of the . . . - char *dump_write = NULL, *files_source = NULL; - int opt; + char *dump_write = NULL, *files_source = NULL; + int opt; -- 2.10.1 @@ -352,17 +351,15 @@ in the manual. Kernel Types ------------ -A kernel type defines a high-level kernel policy by aggregating -non-hardware configuration fragments with patches you want to use when -building a Linux kernel of a specific type (e.g. a real-time kernel). -Syntactically, kernel types are no different than features as described -in the ":ref:`kernel-dev/advanced:features`" section. The -:term:`LINUX_KERNEL_TYPE` -variable in the kernel recipe selects the kernel type. For example, in -the ``linux-yocto_4.12.bb`` kernel recipe found in -``poky/meta/recipes-kernel/linux``, a -:ref:`require <bitbake:bitbake-user-manual/bitbake-user-manual-metadata:\`\`require\`\` directive>` directive -includes the ``poky/meta/recipes-kernel/linux/linux-yocto.inc`` file, +A kernel type defines a high-level kernel policy by aggregating non-hardware +configuration fragments with patches you want to use when building a Linux +kernel of a specific type (e.g. a real-time kernel). Syntactically, kernel +types are no different than features as described in the +":ref:`kernel-dev/advanced:features`" section. The :term:`LINUX_KERNEL_TYPE` +variable in the kernel recipe selects the kernel type. For example, in the +``linux-yocto_4.12.bb`` kernel recipe found in ``poky/meta/recipes-kernel/linux``, a +:ref:`require <bitbake-user-manual/bitbake-user-manual-metadata:\`\`require\`\` directive>` +directive includes the ``poky/meta/recipes-kernel/linux/linux-yocto.inc`` file, which has the following statement that defines the default kernel type:: LINUX_KERNEL_TYPE ??= "standard" @@ -566,15 +563,7 @@ Example Many real-world examples are more complex. Like any other ``.scc`` file, BSP descriptions can aggregate features. Consider the Minnow BSP definition given the ``linux-yocto-4.4`` branch of the -``yocto-kernel-cache`` (i.e. -``yocto-kernel-cache/bsp/minnow/minnow.scc``): - -.. note:: - - Although the Minnow Board BSP is unused, the Metadata remains and is - being used here just as an example. - -:: +``yocto-kernel-cache`` (i.e. ``yocto-kernel-cache/bsp/minnow/minnow.scc``):: include cfg/x86.scc include features/eg20t/eg20t.scc @@ -597,6 +586,11 @@ definition given the ``linux-yocto-4.4`` branch of the kconf hardware minnow.cfg kconf hardware minnow-dev.cfg +.. note:: + + Although the Minnow Board BSP is unused, the Metadata remains and is + being used here just as an example. + The ``minnow.scc`` description file includes a hardware configuration fragment (``minnow.cfg``) specific to the Minnow BSP as well as several more general configuration fragments and features enabling hardware @@ -735,11 +729,10 @@ reside in a separate repository. The OpenEmbedded build system adds the Metadata to the build as a "type=kmeta" repository through the :term:`SRC_URI` variable. As an example, consider the following :term:`SRC_URI` statement from the -``linux-yocto_4.12.bb`` kernel recipe:: - - SRC_URI = "git://git.yoctoproject.org/linux-yocto-4.12.git;name=machine;branch=${KBRANCH}; \ - git://git.yoctoproject.org/yocto-kernel-cache;type=kmeta;name=meta;branch=yocto-4.12;destsuffix=${KMETA}" +``linux-yocto_5.15.bb`` kernel recipe:: + SRC_URI = "git://git.yoctoproject.org/linux-yocto.git;name=machine;branch=${KBRANCH};protocol=https \ + git://git.yoctoproject.org/yocto-kernel-cache;type=kmeta;name=meta;branch=yocto-5.15;destsuffix=${KMETA};protocol=https" ``${KMETA}``, in this context, is simply used to name the directory into which the Git fetcher places the Metadata. This behavior is no different diff --git a/documentation/kernel-dev/common.rst b/documentation/kernel-dev/common.rst index 16ef6453bd..fda41694dc 100644 --- a/documentation/kernel-dev/common.rst +++ b/documentation/kernel-dev/common.rst @@ -52,7 +52,7 @@ image and ready to make modifications as described in the ":ref:`kernel-dev/common:using \`\`devtool\`\` to patch the kernel`" section: -1. *Initialize the BitBake Environment:* +#. *Initialize the BitBake Environment:* you need to initialize the BitBake build environment by sourcing the build environment script (i.e. :ref:`structure-core-script`):: @@ -66,19 +66,15 @@ section: (i.e. ``poky``) have been cloned using Git and the local repository is named "poky". -2. *Prepare Your local.conf File:* By default, the - :term:`MACHINE` variable is set to - "qemux86-64", which is fine if you are building for the QEMU emulator - in 64-bit mode. However, if you are not, you need to set the +#. *Prepare Your local.conf File:* By default, the :term:`MACHINE` variable + is set to "qemux86-64", which is fine if you are building for the QEMU + emulator in 64-bit mode. However, if you are not, you need to set the :term:`MACHINE` variable appropriately in your ``conf/local.conf`` file - found in the - :term:`Build Directory` (i.e. - ``poky/build`` in this example). + found in the :term:`Build Directory` (i.e. ``poky/build`` in this example). Also, since you are preparing to work on the kernel image, you need - to set the - :term:`MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS` - variable to include kernel modules. + to set the :term:`MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS` variable to include + kernel modules. In this example we wish to build for qemux86 so we must set the :term:`MACHINE` variable to "qemux86" and also add the "kernel-modules". @@ -87,7 +83,7 @@ section: MACHINE = "qemux86" MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules" -3. *Create a Layer for Patches:* You need to create a layer to hold +#. *Create a Layer for Patches:* You need to create a layer to hold patches created for the kernel image. You can use the ``bitbake-layers create-layer`` command as follows:: @@ -101,16 +97,16 @@ section: For background information on working with common and BSP layers, see the - ":ref:`dev-manual/common-tasks:understanding and creating layers`" + ":ref:`dev-manual/layers:understanding and creating layers`" section in the Yocto Project Development Tasks Manual and the ":ref:`bsp-guide/bsp:bsp layers`" section in the Yocto Project Board Support (BSP) Developer's Guide, respectively. For information on how to use the ``bitbake-layers create-layer`` command to quickly set up a layer, see the - ":ref:`dev-manual/common-tasks:creating a general layer using the \`\`bitbake-layers\`\` script`" + ":ref:`dev-manual/layers:creating a general layer using the \`\`bitbake-layers\`\` script`" section in the Yocto Project Development Tasks Manual. -4. *Inform the BitBake Build Environment About Your Layer:* As directed +#. *Inform the BitBake Build Environment About Your Layer:* As directed when you created your layer, you need to add the layer to the :term:`BBLAYERS` variable in the ``bblayers.conf`` file as follows:: @@ -120,7 +116,7 @@ section: NOTE: Starting bitbake server... $ -5. *Build the Clean Image:* The final step in preparing to work on the +#. *Build the Clean Image:* The final step in preparing to work on the kernel is to build an initial image using ``bitbake``:: $ bitbake core-image-minimal @@ -162,7 +158,7 @@ this procedure leaves you ready to make modifications to the kernel source as described in the ":ref:`kernel-dev/common:using traditional kernel development to patch the kernel`" section: -1. *Initialize the BitBake Environment:* Before you can do anything +#. *Initialize the BitBake Environment:* Before you can do anything using BitBake, you need to initialize the BitBake build environment by sourcing the build environment script (i.e. :ref:`structure-core-script`). @@ -170,8 +166,7 @@ section: checked out for ``poky`` is the Yocto Project &DISTRO_NAME; branch. If you need to checkout out the &DISTRO_NAME; branch, see the ":ref:`dev-manual/start:checking out by branch in poky`" - section in the Yocto Project Development Tasks Manual. - :: + section in the Yocto Project Development Tasks Manual:: $ cd poky $ git branch @@ -186,14 +181,11 @@ section: (i.e. ``poky``) have been cloned using Git and the local repository is named "poky". -2. *Prepare Your local.conf File:* By default, the - :term:`MACHINE` variable is set to - "qemux86-64", which is fine if you are building for the QEMU emulator - in 64-bit mode. However, if you are not, you need to set the - :term:`MACHINE` variable appropriately in your ``conf/local.conf`` file - found in the - :term:`Build Directory` (i.e. - ``poky/build`` in this example). +#. *Prepare Your local.conf File:* By default, the :term:`MACHINE` variable is + set to "qemux86-64", which is fine if you are building for the QEMU emulator + in 64-bit mode. However, if you are not, you need to set the :term:`MACHINE` + variable appropriately in your ``conf/local.conf`` file found in the + :term:`Build Directory` (i.e. ``poky/build`` in this example). Also, since you are preparing to work on the kernel image, you need to set the @@ -207,7 +199,7 @@ section: MACHINE = "qemux86" MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-modules" -3. *Create a Layer for Patches:* You need to create a layer to hold +#. *Create a Layer for Patches:* You need to create a layer to hold patches created for the kernel image. You can use the ``bitbake-layers create-layer`` command as follows:: @@ -220,16 +212,16 @@ section: For background information on working with common and BSP layers, see the - ":ref:`dev-manual/common-tasks:understanding and creating layers`" + ":ref:`dev-manual/layers:understanding and creating layers`" section in the Yocto Project Development Tasks Manual and the ":ref:`bsp-guide/bsp:bsp layers`" section in the Yocto Project Board Support (BSP) Developer's Guide, respectively. For information on how to use the ``bitbake-layers create-layer`` command to quickly set up a layer, see the - ":ref:`dev-manual/common-tasks:creating a general layer using the \`\`bitbake-layers\`\` script`" + ":ref:`dev-manual/layers:creating a general layer using the \`\`bitbake-layers\`\` script`" section in the Yocto Project Development Tasks Manual. -4. *Inform the BitBake Build Environment About Your Layer:* As directed +#. *Inform the BitBake Build Environment About Your Layer:* As directed when you created your layer, you need to add the layer to the :term:`BBLAYERS` variable in the ``bblayers.conf`` file as follows:: @@ -239,7 +231,7 @@ section: NOTE: Starting bitbake server ... $ -5. *Create a Local Copy of the Kernel Git Repository:* You can find Git +#. *Create a Local Copy of the Kernel Git Repository:* You can find Git repositories of supported Yocto Project kernels organized under "Yocto Linux Kernel" in the Yocto Project Source Repositories at :yocto_git:`/`. @@ -251,16 +243,7 @@ section: ``standard/base`` branch. The following commands show how to create a local copy of the - ``linux-yocto-4.12`` kernel and be in the ``standard/base`` branch. - - .. note:: - - The ``linux-yocto-4.12`` kernel can be used with the Yocto Project 2.4 - release and forward. - You cannot use the ``linux-yocto-4.12`` kernel with releases prior to - Yocto Project 2.4. - - :: + ``linux-yocto-4.12`` kernel and be in the ``standard/base`` branch:: $ cd ~ $ git clone git://git.yoctoproject.org/linux-yocto-4.12 --branch standard/base @@ -272,7 +255,14 @@ section: Resolving deltas: 100% (5152604/5152604), done. Checking connectivity... done. Checking out files: 100% (59846/59846), done. -6. *Create a Local Copy of the Kernel Cache Git Repository:* For + .. note:: + + The ``linux-yocto-4.12`` kernel can be used with the Yocto Project 2.4 + release and forward. + You cannot use the ``linux-yocto-4.12`` kernel with releases prior to + Yocto Project 2.4. + +#. *Create a Local Copy of the Kernel Cache Git Repository:* For simplicity, it is recommended that you create your copy of the kernel cache Git repository outside of the :term:`Source Directory`, which is @@ -306,7 +296,7 @@ layer contains its own :term:`BitBake` append files (``.bbappend``) and provides a convenient mechanism to create your own recipe files (``.bb``) as well as store and use kernel patch files. For background information on working with layers, see the -":ref:`dev-manual/common-tasks:understanding and creating layers`" +":ref:`dev-manual/layers:understanding and creating layers`" section in the Yocto Project Development Tasks Manual. .. note:: @@ -314,7 +304,7 @@ section in the Yocto Project Development Tasks Manual. The Yocto Project comes with many tools that simplify tasks you need to perform. One such tool is the ``bitbake-layers create-layer`` command, which simplifies creating a new layer. See the - ":ref:`dev-manual/common-tasks:creating a general layer using the \`\`bitbake-layers\`\` script`" + ":ref:`dev-manual/layers:creating a general layer using the \`\`bitbake-layers\`\` script`" section in the Yocto Project Development Tasks Manual for information on how to use this script to quick set up a new layer. @@ -323,19 +313,15 @@ following section describes how to create a layer without the aid of tools. These steps assume creation of a layer named ``mylayer`` in your home directory: -1. *Create Structure*: Create the layer's structure:: +#. *Create Structure*: Create the layer's structure:: - $ mkdir meta-mylayer - $ mkdir meta-mylayer/conf - $ mkdir meta-mylayer/recipes-kernel - $ mkdir meta-mylayer/recipes-kernel/linux - $ mkdir meta-mylayer/recipes-kernel/linux/linux-yocto + $ mkdir -p meta-mylayer/conf meta-mylayer/recipes-kernel/linux/linux-yocto The ``conf`` directory holds your configuration files, while the ``recipes-kernel`` directory holds your append file and eventual patch files. -2. *Create the Layer Configuration File*: Move to the +#. *Create the Layer Configuration File*: Move to the ``meta-mylayer/conf`` directory and create the ``layer.conf`` file as follows:: @@ -352,7 +338,7 @@ home directory: Notice ``mylayer`` as part of the last three statements. -3. *Create the Kernel Recipe Append File*: Move to the +#. *Create the Kernel Recipe Append File*: Move to the ``meta-mylayer/recipes-kernel/linux`` directory and create the kernel's append file. This example uses the ``linux-yocto-4.12`` kernel. Thus, the name of the append file is @@ -360,14 +346,14 @@ home directory: FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:" - SRC_URI:append = " file://patch-file-one.patch" - SRC_URI:append = " file://patch-file-two.patch" - SRC_URI:append = " file://patch-file-three.patch" + SRC_URI += "file://patch-file-one.patch" + SRC_URI += "file://patch-file-two.patch" + SRC_URI += "file://patch-file-three.patch" The :term:`FILESEXTRAPATHS` and :term:`SRC_URI` statements enable the OpenEmbedded build system to find patch files. For more information on using append files, see the - ":ref:`dev-manual/common-tasks:appending other layers metadata with your layer`" + ":ref:`dev-manual/layers:appending other layers metadata with your layer`" section in the Yocto Project Development Tasks Manual. Modifying an Existing Recipe @@ -397,13 +383,13 @@ Creating the Append File You create this file in your custom layer. You also name it accordingly based on the linux-yocto recipe you are using. For example, if you are -modifying the ``meta/recipes-kernel/linux/linux-yocto_4.12.bb`` recipe, +modifying the ``meta/recipes-kernel/linux/linux-yocto_6.1.bb`` recipe, the append file will typically be located as follows within your custom layer: .. code-block:: none - your-layer/recipes-kernel/linux/linux-yocto_4.12.bbappend + your-layer/recipes-kernel/linux/linux-yocto_6.1.bbappend The append file should initially extend the :term:`FILESPATH` search path by @@ -431,36 +417,31 @@ As an example, consider the following append file used by the BSPs in .. code-block:: none - meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend + meta-yocto-bsp/recipes-kernel/linux/linux-yocto_6.1.bbappend Here are the contents of this file. Be aware that the actual commit ID strings in this example listing might be different than the actual -strings in the file from the ``meta-yocto-bsp`` layer upstream. -:: - - KBRANCH:genericx86 = "standard/base" - KBRANCH:genericx86-64 = "standard/base" +strings in the file from the ``meta-yocto-bsp`` layer upstream:: - KMACHINE:genericx86 ?= "common-pc" - KMACHINE:genericx86-64 ?= "common-pc-64" - KBRANCH:edgerouter = "standard/edgerouter" - KBRANCH:beaglebone = "standard/beaglebone" + KBRANCH:genericx86 = "v6.1/standard/base" + KBRANCH:genericx86-64 = "v6.1/standard/base" + KBRANCH:beaglebone-yocto = "v6.1/standard/beaglebone" - SRCREV_machine:genericx86 ?= "d09f2ce584d60ecb7890550c22a80c48b83c2e19" - SRCREV_machine:genericx86-64 ?= "d09f2ce584d60ecb7890550c22a80c48b83c2e19" - SRCREV_machine:edgerouter ?= "b5c8cfda2dfe296410d51e131289fb09c69e1e7d" - SRCREV_machine:beaglebone ?= "b5c8cfda2dfe296410d51e131289fb09c69e1e7d" + KMACHINE:genericx86 ?= "common-pc" + KMACHINE:genericx86-64 ?= "common-pc-64" + KMACHINE:beaglebone-yocto ?= "beaglebone" + SRCREV_machine:genericx86 ?= "6ec439b4b456ce929c4c07fe457b5d6a4b468e86" + SRCREV_machine:genericx86-64 ?= "6ec439b4b456ce929c4c07fe457b5d6a4b468e86" + SRCREV_machine:beaglebone-yocto ?= "423e1996694b61fbfc8ec3bf062fc6461d64fde1" - COMPATIBLE_MACHINE:genericx86 = "genericx86" - COMPATIBLE_MACHINE:genericx86-64 = "genericx86-64" - COMPATIBLE_MACHINE:edgerouter = "edgerouter" - COMPATIBLE_MACHINE:beaglebone = "beaglebone" + COMPATIBLE_MACHINE:genericx86 = "genericx86" + COMPATIBLE_MACHINE:genericx86-64 = "genericx86-64" + COMPATIBLE_MACHINE:beaglebone-yocto = "beaglebone-yocto" - LINUX_VERSION:genericx86 = "4.12.7" - LINUX_VERSION:genericx86-64 = "4.12.7" - LINUX_VERSION:edgerouter = "4.12.10" - LINUX_VERSION:beaglebone = "4.12.10" + LINUX_VERSION:genericx86 = "6.1.30" + LINUX_VERSION:genericx86-64 = "6.1.30" + LINUX_VERSION:beaglebone-yocto = "6.1.20" This append file contains statements used to support several BSPs that ship with the @@ -497,8 +478,7 @@ For example, suppose you had some configuration options in a file called ``network_configs.cfg``. You can place that file inside a directory named ``linux-yocto`` and then add a :term:`SRC_URI` statement such as the following to the append file. When the OpenEmbedded build system builds -the kernel, the configuration options are picked up and applied. -:: +the kernel, the configuration options are picked up and applied:: SRC_URI += "file://network_configs.cfg" @@ -661,12 +641,12 @@ append files, you can direct the OpenEmbedded build system to use a To specify an "in-tree" ``defconfig`` file, use the following statement form:: - KBUILD_DEFCONFIG_KMACHINE ?= "defconfig_file" + KBUILD_DEFCONFIG:<machine> ?= "defconfig_file" -Here is an example -that assigns the :term:`KBUILD_DEFCONFIG` variable based on "raspberrypi2" -and provides the path to the "in-tree" ``defconfig`` file to be used for -a Raspberry Pi 2, which is based on the Broadcom 2708/2709 chipset:: +Here is an example that assigns the :term:`KBUILD_DEFCONFIG` variable utilizing +an override for the "raspberrypi2" :term:`MACHINE` and provides the path to the +"in-tree" ``defconfig`` file to be used for a Raspberry Pi 2, which is based on +the Broadcom 2708/2709 chipset:: KBUILD_DEFCONFIG:raspberrypi2 ?= "bcm2709_defconfig" @@ -707,7 +687,7 @@ modified image causes the added messages to appear on the emulator's console. The example is a continuation of the setup procedure found in the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Section. -1. *Check Out the Kernel Source Files:* First you must use ``devtool`` +#. *Check Out the Kernel Source Files:* First you must use ``devtool`` to checkout the kernel source code in its workspace. .. note:: @@ -735,10 +715,10 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se You can safely ignore these messages. The source code is correctly checked out. -2. *Edit the Source Files* Follow these steps to make some simple +#. *Edit the Source Files* Follow these steps to make some simple changes to the source files: - 1. *Change the working directory*: In the previous step, the output + #. *Change the working directory*: In the previous step, the output noted where you can find the source files (e.g. ``poky_sdk/workspace/sources/linux-yocto``). Change to where the kernel source code is before making your edits to the @@ -746,7 +726,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se $ cd poky_sdk/workspace/sources/linux-yocto - 2. *Edit the source file*: Edit the ``init/calibrate.c`` file to have + #. *Edit the source file*: Edit the ``init/calibrate.c`` file to have the following changes:: void calibrate_delay(void) @@ -766,14 +746,17 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se . . -3. *Build the Updated Kernel Source:* To build the updated kernel +#. *Build the Updated Kernel Source:* To build the updated kernel source, use ``devtool``:: $ devtool build linux-yocto -4. *Create the Image With the New Kernel:* Use the +#. *Create the Image With the New Kernel:* Use the ``devtool build-image`` command to create a new image that has the - new kernel. + new kernel:: + + $ cd ~ + $ devtool build-image core-image-minimal .. note:: @@ -783,20 +766,15 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se :yocto_wiki:`TipsAndTricks/KernelDevelopmentWithEsdk </TipsAndTricks/KernelDevelopmentWithEsdk>` Wiki Page. - :: - - $ cd ~ - $ devtool build-image core-image-minimal - -5. *Test the New Image:* For this example, you can run the new image +#. *Test the New Image:* For this example, you can run the new image using QEMU to verify your changes: - 1. *Boot the image*: Boot the modified image in the QEMU emulator + #. *Boot the image*: Boot the modified image in the QEMU emulator using this command:: $ runqemu qemux86 - 2. *Verify the changes*: Log into the machine using ``root`` with no + #. *Verify the changes*: Log into the machine using ``root`` with no password and then use the following shell command to scroll through the console's boot output. @@ -808,7 +786,7 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se the results of your ``printk`` statements as part of the output when you scroll down the console window. -6. *Stage and commit your changes*: Change +#. *Stage and commit your changes*: Change your working directory to where you modified the ``calibrate.c`` file and use these Git commands to stage and commit your changes:: @@ -817,10 +795,9 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se $ git add init/calibrate.c $ git commit -m "calibrate: Add printk example" -7. *Export the Patches and Create an Append File:* To export your +#. *Export the Patches and Create an Append File:* To export your commits as patches and create a ``.bbappend`` file, use the following - command. This example uses the previously established layer named ``meta-mylayer``. - :: + command. This example uses the previously established layer named ``meta-mylayer``:: $ devtool finish linux-yocto ~/meta-mylayer @@ -834,10 +811,9 @@ the ":ref:`kernel-dev/common:getting ready to develop using \`\`devtool\`\``" Se finishes, the patches and the ``.bbappend`` file are located in the ``~/meta-mylayer/recipes-kernel/linux`` directory. -8. *Build the Image With Your Modified Kernel:* You can now build an +#. *Build the Image With Your Modified Kernel:* You can now build an image that includes your kernel patches. Execute the following - command from your - :term:`Build Directory` in the terminal + command from your :term:`Build Directory` in the terminal set up to run BitBake:: $ cd poky/build @@ -873,20 +849,20 @@ found in the ":ref:`kernel-dev/common:getting ready for traditional kernel development`" Section. -1. *Edit the Source Files* Prior to this step, you should have used Git +#. *Edit the Source Files* Prior to this step, you should have used Git to create a local copy of the repository for your kernel. Assuming you created the repository as directed in the ":ref:`kernel-dev/common:getting ready for traditional kernel development`" section, use the following commands to edit the ``calibrate.c`` file: - 1. *Change the working directory*: You need to locate the source + #. *Change the working directory*: You need to locate the source files in the local copy of the kernel Git repository. Change to where the kernel source code is before making your edits to the ``calibrate.c`` file:: $ cd ~/linux-yocto-4.12/init - 2. *Edit the source file*: Edit the ``calibrate.c`` file to have the + #. *Edit the source file*: Edit the ``calibrate.c`` file to have the following changes:: void calibrate_delay(void) @@ -906,7 +882,7 @@ Section. . . -2. *Stage and Commit Your Changes:* Use standard Git commands to stage +#. *Stage and Commit Your Changes:* Use standard Git commands to stage and commit the changes you just made:: $ git add calibrate.c @@ -916,7 +892,7 @@ Section. stage and commit your changes, the OpenEmbedded Build System will not pick up the changes. -3. *Update Your local.conf File to Point to Your Source Files:* In +#. *Update Your local.conf File to Point to Your Source Files:* In addition to your ``local.conf`` file specifying to use "kernel-modules" and the "qemux86" machine, it must also point to the updated kernel source files. Add @@ -940,21 +916,21 @@ Section. be sure to specify the correct branch and machine types. For this example, the branch is ``standard/base`` and the machine is ``qemux86``. -4. *Build the Image:* With the source modified, your changes staged and +#. *Build the Image:* With the source modified, your changes staged and committed, and the ``local.conf`` file pointing to the kernel files, you can now use BitBake to build the image:: $ cd poky/build $ bitbake core-image-minimal -5. *Boot the image*: Boot the modified image in the QEMU emulator using +#. *Boot the image*: Boot the modified image in the QEMU emulator using this command. When prompted to login to the QEMU console, use "root" with no password:: $ cd poky/build $ runqemu qemux86 -6. *Look for Your Changes:* As QEMU booted, you might have seen your +#. *Look for Your Changes:* As QEMU booted, you might have seen your changes rapidly scroll by. If not, use these commands to see your changes: @@ -966,7 +942,7 @@ Section. ``printk`` statements as part of the output when you scroll down the console window. -7. *Generate the Patch File:* Once you are sure that your patch works +#. *Generate the Patch File:* Once you are sure that your patch works correctly, you can generate a ``*.patch`` file in the kernel source repository:: @@ -974,7 +950,7 @@ Section. $ git format-patch -1 0001-calibrate.c-Added-some-printk-statements.patch -8. *Move the Patch File to Your Layer:* In order for subsequent builds +#. *Move the Patch File to Your Layer:* In order for subsequent builds to pick up patches, you need to move the patch file you created in the previous step to your layer ``meta-mylayer``. For this example, the layer created earlier is located in your home directory as @@ -984,9 +960,7 @@ Section. additional structure to your layer using the following commands:: $ cd ~/meta-mylayer - $ mkdir recipes-kernel - $ mkdir recipes-kernel/linux - $ mkdir recipes-kernel/linux/linux-yocto + $ mkdir -p recipes-kernel recipes-kernel/linux/linux-yocto Once you have created this hierarchy in your layer, you can move the patch file using the @@ -994,7 +968,7 @@ Section. $ mv ~/linux-yocto-4.12/init/0001-calibrate.c-Added-some-printk-statements.patch ~/meta-mylayer/recipes-kernel/linux/linux-yocto -9. *Create the Append File:* Finally, you need to create the +#. *Create the Append File:* Finally, you need to create the ``linux-yocto_4.12.bbappend`` file and insert statements that allow the OpenEmbedded build system to find the patch. The append file needs to be in your layer's ``recipes-kernel/linux`` directory and it @@ -1002,7 +976,7 @@ Section. contents:: FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:" - SRC_URI:append = " file://0001-calibrate.c-Added-some-printk-statements.patch" + SRC_URI += "file://0001-calibrate.c-Added-some-printk-statements.patch" The :term:`FILESEXTRAPATHS` and :term:`SRC_URI` statements enable the OpenEmbedded build system to find the patch file. @@ -1010,7 +984,7 @@ Section. For more information on append files and patches, see the ":ref:`kernel-dev/common:creating the append file`" and ":ref:`kernel-dev/common:applying patches`" sections. You can also see the - ":ref:`dev-manual/common-tasks:appending other layers metadata with your layer`" + ":ref:`dev-manual/layers:appending other layers metadata with your layer`" section in the Yocto Project Development Tasks Manual. .. note:: @@ -1021,7 +995,7 @@ Section. the following sequence of commands:: $ cd poky/build - $ bitbake -c cleanall yocto-linux + $ bitbake -c cleanall linux-yocto $ bitbake core-image-minimal -c cleanall $ bitbake core-image-minimal $ runqemu qemux86 @@ -1051,15 +1025,14 @@ Using ``menuconfig`` 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 https://en.wikipedia.org/wiki/Menuconfig. +``menuconfig``, see :wikipedia:`Menuconfig`. To use the ``menuconfig`` tool in the Yocto Project development environment, you must do the following: - Because you launch ``menuconfig`` using BitBake, you must be sure to - set up your environment by running the - :ref:`structure-core-script` script found in - the :term:`Build Directory`. + set up your environment by running the :ref:`structure-core-script` script + found in the :term:`Build Directory`. - You must be sure of the state of your build's configuration in the :term:`Source Directory`. @@ -1100,7 +1073,7 @@ Consider an example that configures the "CONFIG_SMP" setting for the .. note:: The OpenEmbedded build system recognizes this kernel as ``linux-yocto`` - through Metadata (e.g. :term:`PREFERRED_VERSION`\ ``_linux-yocto ?= "12.4%"``). + through Metadata (e.g. :term:`PREFERRED_VERSION`\ ``_linux-yocto ?= "4.12%"``). Once ``menuconfig`` launches, use the interface to navigate through the selections to find the configuration settings in which you are @@ -1111,10 +1084,10 @@ can find the option under "Processor Type and Features". To deselect Multi-Processing Support" and enter "N" to clear the asterisk. When you are finished, exit out and save the change. -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 +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 :term:`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-yocto-4.12`` kernel and you were building a QEMU image targeted for ``x86`` architecture, @@ -1240,7 +1213,7 @@ saved, and one freshly created using the ``menuconfig`` tool. To create a configuration fragment using this method, follow these steps: -1. *Complete a Build Through Kernel Configuration:* Complete a build at +#. *Complete a Build Through Kernel Configuration:* Complete a build at least through the kernel configuration task as follows:: $ bitbake linux-yocto -c kernel_configme -f @@ -1250,11 +1223,11 @@ steps: your build state might become unknown, it is best to run this task prior to starting ``menuconfig``. -2. *Launch menuconfig:* Run the ``menuconfig`` command:: +#. *Launch menuconfig:* Run the ``menuconfig`` command:: $ bitbake linux-yocto -c menuconfig -3. *Create the Configuration Fragment:* Run the ``diffconfig`` command +#. *Create the Configuration Fragment:* Run the ``diffconfig`` command to prepare a configuration fragment. The resulting file ``fragment.cfg`` is placed in the ``${``\ :term:`WORKDIR`\ ``}`` @@ -1316,7 +1289,7 @@ In order to run this task, you must have an existing ``.config`` file. See the ":ref:`kernel-dev/common:using \`\`menuconfig\`\``" section for information on how to create a configuration file. -Following is sample output from the ``do_kernel_configcheck`` task: +Here is sample output from the :ref:`ref-tasks-kernel_configcheck` task: .. code-block:: none @@ -1396,12 +1369,12 @@ 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 +As part of the kernel build process, the :ref:`ref-tasks-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. +- Requested options that did not make it into the final ``.config`` file. - Configuration items that appear twice in the same configuration fragment. @@ -1425,18 +1398,18 @@ configuration. To streamline the configuration, do the following: -1. *Use a Working Configuration:* Start with a full configuration that +#. *Use a Working Configuration:* Start with a full configuration that you know works. Be sure the configuration builds and boots successfully. Use this configuration file as your baseline. -2. *Run Configure and Check Tasks:* Separately run the - ``do_kernel_configme`` and ``do_kernel_configcheck`` tasks:: +#. *Run Configure and Check Tasks:* Separately run the + :ref:`ref-tasks-kernel_configme` and :ref:`ref-tasks-kernel_configcheck` tasks:: $ bitbake linux-yocto -c kernel_configme -f $ bitbake linux-yocto -c kernel_configcheck -f -3. *Process the Results:* Take the resulting list of files from the - ``do_kernel_configcheck`` task warnings and do the following: +#. *Process the Results:* Take the resulting list of files from the + :ref:`ref-tasks-kernel_configcheck` task warnings and do the following: - Drop values that are redefined in the fragment but do not change the final ``.config`` file. @@ -1448,9 +1421,9 @@ To streamline the configuration, do the following: - Remove repeated and invalid options. -4. *Re-Run Configure and Check Tasks:* After you have worked through the +#. *Re-Run Configure and Check Tasks:* 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 + :ref:`ref-tasks-kernel_configme` and :ref:`ref-tasks-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. @@ -1479,20 +1452,20 @@ If you build a kernel image and the version string has a "+" or a "-dirty" at the end, it means there are uncommitted modifications in the kernel's source directory. Follow these steps to clean up the version string: -1. *Discover the Uncommitted Changes:* Go to the kernel's locally cloned +#. *Discover the Uncommitted Changes:* Go to the kernel's locally cloned Git repository (source directory) and use the following Git command to list the files that have been changed, added, or removed:: $ git status -2. *Commit the Changes:* You should commit those changes to the kernel +#. *Commit the Changes:* You should commit those changes to the kernel source tree regardless of whether or not you will save, export, or use the changes:: $ git add $ git commit -s -a -m "getting rid of -dirty" -3. *Rebuild the Kernel Image:* Once you commit the changes, rebuild the +#. *Rebuild the Kernel Image:* Once you commit the changes, rebuild the kernel. Depending on your particular kernel development workflow, the @@ -1526,18 +1499,18 @@ You can find this recipe in the ``poky`` Git repository: Here are some basic steps you can use to work with your own sources: -1. *Create a Copy of the Kernel Recipe:* Copy the +#. *Create a Copy of the Kernel Recipe:* Copy the ``linux-yocto-custom.bb`` recipe to your layer and give it a meaningful name. The name should include the version of the Yocto Linux kernel you are using (e.g. ``linux-yocto-myproject_4.12.bb``, where "4.12" is the base version of the Linux kernel with which you would be working). -2. *Create a Directory for Your Patches:* In the same directory inside +#. *Create a Directory for Your Patches:* In the same directory inside your layer, create a matching directory to store your patches and configuration files (e.g. ``linux-yocto-myproject``). -3. *Ensure You Have Configurations:* Make sure you have either a +#. *Ensure You Have Configurations:* Make sure you have either a ``defconfig`` file or configuration fragment files in your layer. When you use the ``linux-yocto-custom.bb`` recipe, you must specify a configuration. If you do not have a ``defconfig`` file, you can run @@ -1562,7 +1535,7 @@ Here are some basic steps you can use to work with your own sources: ``arch/arm/configs`` and use the one that is the best starting point for your board). -4. *Edit the Recipe:* Edit the following variables in your recipe as +#. *Edit the Recipe:* Edit the following variables in your recipe as appropriate for your project: - :term:`SRC_URI`: The @@ -1611,7 +1584,7 @@ Here are some basic steps you can use to work with your own sources: COMPATIBLE_MACHINE = "qemux86|qemux86-64" -5. *Customize Your Recipe as Needed:* Provide further customizations to +#. *Customize Your Recipe as Needed:* Provide further customizations to your recipe as needed just as you would customize an existing linux-yocto recipe. See the ":ref:`ref-manual/devtool-reference:modifying an existing recipe`" section @@ -1695,19 +1668,17 @@ looks much like the one provided with the ``hello-mod`` template:: SRC := $(shell pwd) all: - $(MAKE) -C $(KERNEL_SRC) M=$(SRC) + $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install: - $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install + $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install ... The important point to note here is the :term:`KERNEL_SRC` variable. The -:ref:`module <ref-classes-module>` class sets this variable and the -:term:`KERNEL_PATH` variable to -``${STAGING_KERNEL_DIR}`` with the necessary Linux kernel build -information to build modules. If your module ``Makefile`` uses a -different variable, you might want to override the -:ref:`ref-tasks-compile` step, or +:ref:`ref-classes-module` class sets this variable and the :term:`KERNEL_PATH` +variable to ``${STAGING_KERNEL_DIR}`` with the necessary Linux kernel build +information to build modules. If your module ``Makefile`` uses a different +variable, you might want to override the :ref:`ref-tasks-compile` step, or create a patch to the ``Makefile`` to work with the more typical :term:`KERNEL_SRC` or :term:`KERNEL_PATH` variables. @@ -1749,7 +1720,7 @@ tree. Using Git is an efficient way to see what has changed in the tree. What Changed in a Kernel? ------------------------- -Following are a few examples that show how to use Git commands to +Here are a few examples that show how to use Git commands to examine changes. These examples are by no means the only way to see changes. @@ -1769,8 +1740,7 @@ Here is an example that looks at what has changed in the ``emenlow`` branch of the ``linux-yocto-3.19`` kernel. The lower commit range is the commit associated with the ``standard/base`` branch, while the upper commit range is the commit associated with the ``standard/emenlow`` -branch. -:: +branch:: $ git whatchanged origin/standard/base..origin/standard/emenlow @@ -1844,7 +1814,7 @@ kernel features. Consider the following example that adds the "test.scc" feature to the build. -1. *Create the Feature File:* Create a ``.scc`` file and locate it just +#. *Create the Feature File:* Create a ``.scc`` file and locate it just as you would any other patch file, ``.cfg`` file, or fetcher item you specify in the :term:`SRC_URI` statement. @@ -1872,19 +1842,19 @@ build. ``linux-yocto`` directory has both the feature ``test.scc`` file and a similarly named configuration fragment file ``test.cfg``. -2. *Add the Feature File to SRC_URI:* Add the ``.scc`` file to the +#. *Add the Feature File to SRC_URI:* Add the ``.scc`` file to the recipe's :term:`SRC_URI` statement:: - SRC_URI:append = " file://test.scc" + SRC_URI += "file://test.scc" The leading space before the path is important as the path is appended to the existing path. -3. *Specify the Feature as a Kernel Feature:* Use the +#. *Specify the Feature as a Kernel Feature:* Use the :term:`KERNEL_FEATURES` statement to specify the feature as a kernel feature:: - KERNEL_FEATURES:append = " test.scc" + KERNEL_FEATURES += "test.scc" The OpenEmbedded build system processes the kernel feature when it builds the kernel. diff --git a/documentation/kernel-dev/concepts-appx.rst b/documentation/kernel-dev/concepts-appx.rst index 63c5124a57..6a2fe4bb0b 100644 --- a/documentation/kernel-dev/concepts-appx.rst +++ b/documentation/kernel-dev/concepts-appx.rst @@ -319,8 +319,7 @@ image. The following figure shows the temporary file structure created on your host system when you build the kernel using BitBake. This -:term:`Build Directory` contains all the -source files used during the build. +:term:`Build Directory` contains all the source files used during the build. .. image:: figures/kernel-overview-2-generic.png :align: center diff --git a/documentation/kernel-dev/faq.rst b/documentation/kernel-dev/faq.rst index e40e3ff372..4dffa90dbd 100644 --- a/documentation/kernel-dev/faq.rst +++ b/documentation/kernel-dev/faq.rst @@ -36,9 +36,9 @@ How do I install/not-install the kernel image on the root filesystem? The kernel image (e.g. ``vmlinuz``) is provided by the ``kernel-image`` package. Image recipes depend on ``kernel-base``. To specify whether or not the kernel image is installed in the generated -root filesystem, override ``RDEPENDS:${KERNEL_PACKAGE_NAME}-base`` to include or not +root filesystem, override ``RRECOMMENDS:${KERNEL_PACKAGE_NAME}-base`` to include or not include "kernel-image". See the -":ref:`dev-manual/common-tasks:appending other layers metadata with your layer`" +":ref:`dev-manual/layers:appending other layers metadata with your layer`" section in the Yocto Project Development Tasks Manual for information on how to use an append file to override metadata. diff --git a/documentation/kernel-dev/intro.rst b/documentation/kernel-dev/intro.rst index 4ff4dc7d35..a663733a1d 100644 --- a/documentation/kernel-dev/intro.rst +++ b/documentation/kernel-dev/intro.rst @@ -87,7 +87,7 @@ understand the following documentation: as described in the Yocto Project Application Development and the Extensible Software Development Kit (eSDK) manual. -- The ":ref:`dev-manual/common-tasks:understanding and creating layers`" +- The ":ref:`dev-manual/layers:understanding and creating layers`" section in the Yocto Project Development Tasks Manual. - The ":ref:`kernel-dev/intro:kernel modification workflow`" section. @@ -108,12 +108,12 @@ general information and references for further information. .. image:: figures/kernel-dev-flow.png :width: 100% -1. *Set up Your Host Development System to Support Development Using the +#. *Set up Your Host Development System to Support Development Using the Yocto Project*: See the ":doc:`/dev-manual/start`" section in the Yocto Project Development Tasks Manual for options on how to get a build host ready to use the Yocto Project. -2. *Set Up Your Host Development System for Kernel Development:* It is +#. *Set Up Your Host Development System for Kernel Development:* It is recommended that you use ``devtool`` for kernel development. Alternatively, you can use traditional kernel development methods with the Yocto Project. Either way, there are @@ -131,10 +131,10 @@ general information and references for further information. ":ref:`kernel-dev/common:getting ready for traditional kernel development`" section. -3. *Make Changes to the Kernel Source Code if applicable:* Modifying the +#. *Make Changes to the Kernel Source Code if applicable:* Modifying the kernel does not always mean directly changing source files. However, if you have to do this, you make the changes to the files in the - Yocto's Build Directory if you are using ``devtool``. For more + Yocto's :term:`Build Directory` if you are using ``devtool``. For more information, see the ":ref:`kernel-dev/common:using \`\`devtool\`\` to patch the kernel`" section. @@ -144,7 +144,7 @@ general information and references for further information. ":ref:`kernel-dev/common:using traditional kernel development to patch the kernel`" section. -4. *Make Kernel Configuration Changes if Applicable:* If your situation +#. *Make Kernel Configuration Changes if Applicable:* If your situation calls for changing the kernel's configuration, you can use :ref:`menuconfig <kernel-dev/common:using \`\`menuconfig\`\`>`, which allows you to @@ -155,7 +155,7 @@ general information and references for further information. .. note:: Try to resist the temptation to directly edit an existing ``.config`` - file, which is found in the Build Directory among the source code + file, which is found in the :term:`Build Directory` among the source code used for the build. Doing so, can produce unexpected results when the OpenEmbedded build system regenerates the configuration file. @@ -169,7 +169,7 @@ general information and references for further information. Additionally, if you are working in a BSP layer and need to modify the BSP's kernel's configuration, you can use ``menuconfig``. -5. *Rebuild the Kernel Image With Your Changes:* Rebuilding the kernel +#. *Rebuild the Kernel Image With Your Changes:* Rebuilding the kernel image applies your changes. Depending on your target hardware, you can verify your changes on actual hardware or perhaps QEMU. diff --git a/documentation/kernel-dev/maint-appx.rst b/documentation/kernel-dev/maint-appx.rst index d968c856f6..53b7376089 100644 --- a/documentation/kernel-dev/maint-appx.rst +++ b/documentation/kernel-dev/maint-appx.rst @@ -92,11 +92,11 @@ top-level kernel feature or BSP. The following actions effectively provide the Metadata and create the tree that includes the new feature, patch, or BSP: -1. *Pass Feature to the OpenEmbedded Build System:* A top-level kernel +#. *Pass Feature to the OpenEmbedded Build System:* A top-level kernel feature is passed to the kernel build subsystem. Normally, this feature is a BSP for a particular kernel type. -2. *Locate Feature:* The file that describes the top-level feature is +#. *Locate Feature:* The file that describes the top-level feature is located by searching these system directories: - The in-tree kernel-cache directories, which are located in the @@ -112,31 +112,31 @@ patch, or BSP: bsp_root_name-kernel_type.scc -3. *Expand Feature:* Once located, the feature description is either +#. *Expand Feature:* Once located, the feature description is either expanded into a simple script of actions, or into an existing equivalent script that is already part of the shipped kernel. -4. *Append Extra Features:* Extra features are appended to the top-level +#. *Append Extra Features:* Extra features are appended to the top-level feature description. These features can come from the :term:`KERNEL_FEATURES` variable in recipes. -5. *Locate, Expand, and Append Each Feature:* Each extra feature is +#. *Locate, Expand, and Append Each Feature:* Each extra feature is located, expanded and appended to the script as described in step three. -6. *Execute the Script:* The script is executed to produce files +#. *Execute the Script:* The script is executed to produce files ``.scc`` and ``.cfg`` files in appropriate directories of the ``yocto-kernel-cache`` repository. These files are descriptions of all the branches, tags, patches and configurations that need to be applied to the base Git repository to completely create the source (build) branch for the new BSP or feature. -7. *Clone Base Repository:* The base repository is cloned, and the +#. *Clone Base Repository:* The base repository is cloned, and the actions listed in the ``yocto-kernel-cache`` directories are applied to the tree. -8. *Perform Cleanup:* The Git repositories are left with the desired +#. *Perform Cleanup:* The Git repositories are left with the desired branches checked out and any required branching, patching and tagging has been performed. @@ -229,6 +229,5 @@ This behavior means that all the generated files for a particular machine or BSP are now in the build tree directory. The files include the final ``.config`` file, all the ``.o`` files, the ``.a`` files, and so forth. Since each machine or BSP has its own separate -:term:`Build Directory` in its own separate -branch of the Git repository, you can easily switch between different -builds. +:term:`Build Directory` in its own separate branch of the Git repository, +you can easily switch between different builds. |