Message ID | 20220216201731.2699414-1-alhe@linux.microsoft.com |
---|---|
State | Accepted |
Commit | 7853ab3df82c27ba309879a66a084b2e597dc1e5 |
Headers | show |
Series | [v2] documentation: Add multiconfig initramfs configuration: | expand |
Hi Alejandro, On 2/16/22 21:17, Alejandro Hernandez Samaniego wrote: > dev-manual/common-tasks.rst: Add section to create an initramfs > image from a separate multiconfig. > > ref-manual/variables.rst: Add new variable definitions for > INITRAMFS_DEPLOY_DIR_IMAGE and INITRAMFS_MULTICONFIG > > Signed-off-by: Alejandro Enedino Hernandez Samaniego <alhe@linux.microsoft.com> > --- > documentation/dev-manual/common-tasks.rst | 42 +++++++++++++++++++++++ > documentation/ref-manual/variables.rst | 17 +++++++++ > 2 files changed, 59 insertions(+) > > diff --git a/documentation/dev-manual/common-tasks.rst b/documentation/dev-manual/common-tasks.rst > index d35b590ee..dec44d378 100644 > --- a/documentation/dev-manual/common-tasks.rst > +++ b/documentation/dev-manual/common-tasks.rst > @@ -3919,6 +3919,48 @@ Follow these steps to create an initramfs image: > :term:`INITRAMFS_IMAGE_BUNDLE` > variable described earlier. > > +Bundling an Initramfs Image From a Separate Multiconfig > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > + > +There may be a case where we want to build an initramfs image which does not > +inherit the same distro policy as our main image, for example, we may want > +our main image to use ``TCLIBC="glibc"``, but to use ``TCLIBC="musl"`` in our initramfs > +image to keep a smaller footprint. However, by performing the steps mentioned > +above the initramfs image will inherit ``TCLIBC="glibc"`` without allowing us > +to override it. > + > +To achieve this, you need to perform some additional steps: > + > +1. *Create a multiconfig for your initramfs image:* You can perform the steps > + on ":ref:`dev-manual/common-tasks:building images for multiple targets using multiple configurations`" to create a separate multiconfig. > + For the sake of simplicity let's assume such multiconfig is called: ``initramfscfg.conf`` and > + contains the variables:: > + > + TMPDIR="${TOPDIR}/tmp-initramfscfg" > + TCLIBC="musl" > + > +2. *Set additional initramfs variables on your main configuration:* > + Additionally, on your main configuration (``local.conf``) you need to set the > + variables:: > + > + INITRAMFS_MULTICONFIG = "initramfscfg" > + INITRAMFS_DEPLOY_DIR_IMAGE = "${TOPDIR}/tmp-initramfscfg/deploy/images/${MACHINE}" > + > + The variables :term:`INITRAMFS_MULTICONFIG` and :term:`INITRAMFS_DEPLOY_DIR_IMAGE` > + are used to create a multiconfig dependency from the kernel to the :term:`INITRAMFS_IMAGE` > + to be built coming from the ``initramfscfg`` multiconfig, and to let the > + buildsystem know where the :term:`INITRAMFS_IMAGE` will be located. > + > + Building a system with such configuration will build the kernel using the > + main configuration but the ``do_bundle_initramfs`` task will grab the > + selected :term:`INITRAMFS_IMAGE` from :term:`INITRAMFS_DEPLOY_DIR_IMAGE` > + instead, resulting in a musl based initramfs image bundled in the kernel > + but a glibc based main image. > + > + The same is applicable to avoid inheriting :term:`DISTRO_FEATURES` on :term:`INITRAMFS_IMAGE` > + or to build a different :term:`DISTRO` for it such as ``poky-tiny``. > + > + > Building a Tiny System > ---------------------- > > diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst > index d4f40b692..caa971393 100644 > --- a/documentation/ref-manual/variables.rst > +++ b/documentation/ref-manual/variables.rst > @@ -3554,6 +3554,13 @@ system and gives an overview of their function and contents. > even if the toolchain's binaries are strippable, there are other files > needed for the build that are not strippable. > > + :term:`INITRAMFS_DEPLOY_DIR_IMAGE` > + Indicates the deploy directory used by ``do_bundle_initramfs`` where the > + :term:`INITRAMFS_IMAGE` will be fetched from. > + This variable is set by default to ``${DEPLOY_DIR_IMAGE}`` in the > + :ref:`kernel <ref-classes-kernel>` class and it's only meant to be changed > + when building an initramfs image from a separate multiconfig via :term:`INITRAMFS_MULTICONFIG`. > + > :term:`INITRAMFS_FSTYPES` > Defines the format for the output image of an initial RAM filesystem > (initramfs), which is used during boot. Supported formats are the > @@ -3673,6 +3680,16 @@ system and gives an overview of their function and contents. > See the :term:`MACHINE` variable for additional > information. > > + :term:`INITRAMFS_MULTICONFIG` > + Defines the multiconfig to create a multiconfig dependency to be used by the :ref:`kernel <ref-classes-kernel>` class. > + > + This allows the kernel to bundle an :term:`INITRAMFS_IMAGE` coming from > + a separate multiconfig, this is meant to be used in addition to :term:`INITRAMFS_DEPLOY_DIR_IMAGE`. > + > + For more information on how to bundle an initramfs image from a separate > + multiconfig see the ":ref:`dev-manual/common-tasks:Bundling an Initramfs Image From a Separate Multiconfig`" > + section in the Yocto Project Development Tasks Manual. > + > :term:`INITRAMFS_NAME` > The base name of the initial RAM filesystem image. This variable is > set in the ``meta/classes/kernel-artifact-names.bbclass`` file as Thanks for the update! Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com> ... and merged into the "master-next" branch of yocto-docs. Cheers Michael.
diff --git a/documentation/dev-manual/common-tasks.rst b/documentation/dev-manual/common-tasks.rst index d35b590ee..dec44d378 100644 --- a/documentation/dev-manual/common-tasks.rst +++ b/documentation/dev-manual/common-tasks.rst @@ -3919,6 +3919,48 @@ Follow these steps to create an initramfs image: :term:`INITRAMFS_IMAGE_BUNDLE` variable described earlier. +Bundling an Initramfs Image From a Separate Multiconfig +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +There may be a case where we want to build an initramfs image which does not +inherit the same distro policy as our main image, for example, we may want +our main image to use ``TCLIBC="glibc"``, but to use ``TCLIBC="musl"`` in our initramfs +image to keep a smaller footprint. However, by performing the steps mentioned +above the initramfs image will inherit ``TCLIBC="glibc"`` without allowing us +to override it. + +To achieve this, you need to perform some additional steps: + +1. *Create a multiconfig for your initramfs image:* You can perform the steps + on ":ref:`dev-manual/common-tasks:building images for multiple targets using multiple configurations`" to create a separate multiconfig. + For the sake of simplicity let's assume such multiconfig is called: ``initramfscfg.conf`` and + contains the variables:: + + TMPDIR="${TOPDIR}/tmp-initramfscfg" + TCLIBC="musl" + +2. *Set additional initramfs variables on your main configuration:* + Additionally, on your main configuration (``local.conf``) you need to set the + variables:: + + INITRAMFS_MULTICONFIG = "initramfscfg" + INITRAMFS_DEPLOY_DIR_IMAGE = "${TOPDIR}/tmp-initramfscfg/deploy/images/${MACHINE}" + + The variables :term:`INITRAMFS_MULTICONFIG` and :term:`INITRAMFS_DEPLOY_DIR_IMAGE` + are used to create a multiconfig dependency from the kernel to the :term:`INITRAMFS_IMAGE` + to be built coming from the ``initramfscfg`` multiconfig, and to let the + buildsystem know where the :term:`INITRAMFS_IMAGE` will be located. + + Building a system with such configuration will build the kernel using the + main configuration but the ``do_bundle_initramfs`` task will grab the + selected :term:`INITRAMFS_IMAGE` from :term:`INITRAMFS_DEPLOY_DIR_IMAGE` + instead, resulting in a musl based initramfs image bundled in the kernel + but a glibc based main image. + + The same is applicable to avoid inheriting :term:`DISTRO_FEATURES` on :term:`INITRAMFS_IMAGE` + or to build a different :term:`DISTRO` for it such as ``poky-tiny``. + + Building a Tiny System ---------------------- diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst index d4f40b692..caa971393 100644 --- a/documentation/ref-manual/variables.rst +++ b/documentation/ref-manual/variables.rst @@ -3554,6 +3554,13 @@ system and gives an overview of their function and contents. even if the toolchain's binaries are strippable, there are other files needed for the build that are not strippable. + :term:`INITRAMFS_DEPLOY_DIR_IMAGE` + Indicates the deploy directory used by ``do_bundle_initramfs`` where the + :term:`INITRAMFS_IMAGE` will be fetched from. + This variable is set by default to ``${DEPLOY_DIR_IMAGE}`` in the + :ref:`kernel <ref-classes-kernel>` class and it's only meant to be changed + when building an initramfs image from a separate multiconfig via :term:`INITRAMFS_MULTICONFIG`. + :term:`INITRAMFS_FSTYPES` Defines the format for the output image of an initial RAM filesystem (initramfs), which is used during boot. Supported formats are the @@ -3673,6 +3680,16 @@ system and gives an overview of their function and contents. See the :term:`MACHINE` variable for additional information. + :term:`INITRAMFS_MULTICONFIG` + Defines the multiconfig to create a multiconfig dependency to be used by the :ref:`kernel <ref-classes-kernel>` class. + + This allows the kernel to bundle an :term:`INITRAMFS_IMAGE` coming from + a separate multiconfig, this is meant to be used in addition to :term:`INITRAMFS_DEPLOY_DIR_IMAGE`. + + For more information on how to bundle an initramfs image from a separate + multiconfig see the ":ref:`dev-manual/common-tasks:Bundling an Initramfs Image From a Separate Multiconfig`" + section in the Yocto Project Development Tasks Manual. + :term:`INITRAMFS_NAME` The base name of the initial RAM filesystem image. This variable is set in the ``meta/classes/kernel-artifact-names.bbclass`` file as
dev-manual/common-tasks.rst: Add section to create an initramfs image from a separate multiconfig. ref-manual/variables.rst: Add new variable definitions for INITRAMFS_DEPLOY_DIR_IMAGE and INITRAMFS_MULTICONFIG Signed-off-by: Alejandro Enedino Hernandez Samaniego <alhe@linux.microsoft.com> --- documentation/dev-manual/common-tasks.rst | 42 +++++++++++++++++++++++ documentation/ref-manual/variables.rst | 17 +++++++++ 2 files changed, 59 insertions(+)