From 64f0f60b3fba36ff87fe78ec1e27e6398d206c51 Mon Sep 17 00:00:00 2001 From: Scott Rifenbark Date: Thu, 29 Jun 2017 13:06:27 -0700 Subject: dev-manual, kernel-dev: Moved kernel branch concepts to kernel-dev Fixes [YOCTO #11630] The information in the dev-manual kernel overview area really neeeds to be in the Appendix on kernel structure in the kernel-dev manual. I moved that informtaion to the appendix. Removal of one redundant image was necessary from the dev-manual. The figure was literally repeated in the kernel manual already under a different file name. (From yocto-docs rev: 00ca68e760e41448c225fb1ca4a77f5201434b93) Signed-off-by: Scott Rifenbark Signed-off-by: Richard Purdie --- .../kernel-dev/kernel-dev-concepts-appx.xml | 113 +++++++++++++-------- 1 file changed, 72 insertions(+), 41 deletions(-) (limited to 'documentation/kernel-dev') diff --git a/documentation/kernel-dev/kernel-dev-concepts-appx.xml b/documentation/kernel-dev/kernel-dev-concepts-appx.xml index 3606301cc7..ee40938b5d 100644 --- a/documentation/kernel-dev/kernel-dev-concepts-appx.xml +++ b/documentation/kernel-dev/kernel-dev-concepts-appx.xml @@ -175,74 +175,105 @@
Kernel Architecture + - This section describes the architecture of the kernels available through the - Yocto Project and provides information + This section describes the architecture of the Yocto Linux kernels + available through the Yocto Project and provides information on the mechanisms used to achieve that architecture.
Overview + - As mentioned earlier, a key goal of the Yocto Project is to present the - developer with - a kernel that has a clear and continuous history that is visible to the user. - The architecture and mechanisms used achieve that goal in a manner similar to the - upstream kernel.org. + As mentioned earlier, a key goal of the Yocto Project is + to present the developer with a kernel that has a clear and + continuous history that is visible to the user. + The architecture and mechanisms used achieve that goal in a + manner similar to upstream Linux kernel development in + kernel.org. + - You can think of a Yocto Project kernel as consisting of a baseline Linux kernel with - added features logically structured on top of the baseline. - The features are tagged and organized by way of a branching strategy implemented by the + You can think of a Yocto Linux kernel as consisting of a + baseline Linux kernel with added features logically structured + on top of the baseline. + The features are tagged and organized by way of a branching + strategy implemented by the Yocto Project team using the source code manager (SCM) Git. For information on Git as applied to the Yocto Project, see the - "Git" section in the - Yocto Project Development Manual. - - - The result is that the user has the ability to see the added features and - the commits that make up those features. - In addition to being able to see added features, the user can also view the history of what - made up the baseline kernel. + "Git" section + in the Yocto Project Development Manual. + - The following illustration shows the conceptual Yocto Project kernel. + The result is that the user has the ability to see the added + features and the commits that make up those features. + In addition to being able to see added features, the user + can also view the history of what made up the baseline + Linux kernel. + + The following illustration shows the conceptual Yocto + Linux kernel. + - In the illustration, the "Kernel.org Branch Point" - marks the specific spot (or release) from - which the Yocto Project kernel is created. - From this point "up" in the tree, features and differences are organized and tagged. + In the illustration, the "Kernel.org Branch Point" marks the + specific spot (or Linux kernel release) from which the + Yocto Linux kernel is created. + From this point forward in the tree, features and differences + are organized and tagged. + - The "Yocto Project Baseline Kernel" contains functionality that is common to every kernel - type and BSP that is organized further up the tree. - Placing these common features in the - tree this way means features do not have to be duplicated along individual branches of the - structure. + The "Yocto Project Baseline Kernel" contains functionality that + is common to every kernel type and BSP that is organized + further along in the tree. + Placing these common features in the tree this way means + features do not have to be duplicated along individual + branches of the tree structure. + - From the Yocto Project Baseline Kernel, branch points represent specific functionality - for individual BSPs as well as real-time kernels. - The illustration represents this through three BSP-specific branches and a real-time - kernel branch. - Each branch represents some unique functionality for the BSP or a real-time kernel. + From the Yocto Project Baseline Kernel, branch points represent + specific functionality for individual Board Support Packages + (BSPs) as well as real-time kernels. + The illustration represents this through three BSP-specific + branches and a real-time kernel branch. + Each branch represents some unique functionality for the BSP + or for a real-time Yocto Linux kernel. + - In this example structure, the real-time kernel branch has common features for all - real-time kernels and contains - more branches for individual BSP-specific real-time kernels. + In this example structure, the real-time kernel branch has + common features for all real-time Yocto Linux kernels and + contains more branches for individual BSP-specific real-time + kernels. The illustration shows three branches as an example. - Each branch points the way to specific, unique features for a respective real-time - kernel as they apply to a given BSP. + Each branch points the way to specific, unique features for a + respective real-time kernel as they apply to a given BSP. + - The resulting tree structure presents a clear path of markers (or branches) to the - developer that, for all practical purposes, is the kernel needed for any given set - of requirements. + The resulting tree structure presents a clear path of markers + (or branches) to the developer that, for all practical + purposes, is the Yocto Linux kernel needed for any given set of + requirements. + + Keep in mind the figure does not take into account all the + supported Yocto Linux kernels, but rather shows a single + generic kernel just for conceptual purposes. + Also keep in mind that this structure represents the Yocto + Project + Source Repositories + that are either pulled from during the build or established + on the host development system prior to the build by either + cloning a particular kernel's Git repository or by + downloading and unpacking a tarball. +
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