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//**This page is under construction**// **Overview** An important criterion for evaluating and adopting a software platform is support. The Trusted Firmware-A community has been releasing code from the tip every six months. This model works very well for software innovation and implementing new hardware features. But for platforms in production, this policy does not scale in terms of maintenance, backward compatibility of important software fixes, and overall product lifecycle management. Several open-source software projects (e.g. Ubuntu, Yocto, Linux Kernel) have faced this problem during their lifetime and have implemented a long-term support release as a solution. Long-term support extends the period of software maintenance; it also alters the type and frequency of software updates (patches) to reduce the risk, expense, and disruption of software deployment, while promoting the dependability of the software. It does not necessarily imply technical support. This document proposes a plan to leverage the path chosen by various open source software projects and define a long-term support release strategy. This proposal will not succeed without the support of the community and relies on contributions from Arm, its partners and platform owners. **Current problems** The following are some of the problems slowing down device upgrades. # The investment to maintain a software release and keep it updated with important software changes from upstream is too high # The cost to productize and deploy a newly released version is too high # Lack of tests to cover all scenarios means that a new public release cannot be immediately deployed to the field # Some aspects like documentation, code analysis reports, test reports and long term availability of tools are not available The technical forum for TF-A on 10 Sep, 2020 was focused on this topic to gauge interest and support from the community. To move the discussion forward, this page intends to capture ideas from the community and eventually crystalize a plan that works for everyone. **Expectations from LTS codebase** There is interest from the community to explore the possibility of a long-term release codebase to solve these problems. The following might be some of the expectations from a long-term support release branch. # Well defined policy to detect, report and deploy software fixes for mitigating security issues, stability concerns, erratas and bugs # 100% test coverage with a publicly available report for every changelist # Up-to-date API reference manual at any given changelist # Well documented performance numbers for important use cases # Usage of Long-term supported toolchains # Well defined policy for accepting new changes # Use of publicly available static analysis tools to improve code quality # Well defined release cadence and key quality indicators **Path to first LTS** The LTS topic was [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/ZZ2DDIW2DS4B7QYHYOL7XE4IPUW7LUNT/ | rebooted ]] in the community in May'22. A [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/MT37NYU3PFDLF5F6CRCRJRGD2SMY5BT3/ | proposal ]] was created by @okash and @vwadekar and presented to the community in a tech forum. The recording can be found at https://www.trustedfirmware.org/meetings/tf-a-technical-forum/. Thanks to the response from the community the proposal has now evolved into an execution plan for the first LTS branch. A stake in the ground is to release the first LTS branch in Feb'23. The detailed proposal is [[ https://developer.trustedfirmware.org/F274534 | attached ]]. **Call to action** Reviewers are encouraged to review the proposal and provide feedback. We request more people to try the LTS release when available and make the project a success. **References** - Tech forum discussion (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 10 Sep, 2020. - Tech forum discussions (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 14 July, 2022 and 8 Sep 2022. - LTS branch creation and execution proposal - https://developer.trustedfirmware.org/F274534

//**This page is under construction**// **Overview** An important criterion for evaluating and adopting a software platform is support. The Trusted Firmware-A community has been releasing code from the tip every six months. This model works very well for software innovation and implementing new hardware features. But for platforms in production, this policy does not scale in terms of maintenance, backward compatibility of important software fixes, getting latest security mitigations, and overall product lifecycle management. Several open-source software projects (e.g. Ubuntu, Yocto, Linux Kernel) have faced this problem during their lifetime and have implemented a long-term support release as a solution. Long-term support not only extends the period of software maintenance, but also alters the type and frequency of software updates (patches) to reduce the risk, expense, and disruption of software deployment, while promoting the dependability of the software. It does not necessarily imply technical support. Long-term support is needed for commercial reasons too. More specifically, on the device side, when a product is released, the companies must support it such that the number of changes to the firmware are kept to a minimum to avoid the risk of regression. At the same time, the companies don't want to exclude critical patches such as those for security advisories. Similarly on server side, companies want to minimize the churn when deploying fixes during incident response, e.g. due to critical security bugs. This means that those companies must maintain and backport critical updates to old branches internally. As this effort is duplicated across different companies using TF-A, it makes sense to factor out this effort into a community wide LTS effort. This document proposes a plan to leverage the path chosen by various open-source software projects and define a long-term support release strategy. This proposal will not succeed without the support of the community and relies on their contributions. **Current problems** The following are some of the problems slowing down device upgrades. # The investment to maintain a software release and keep it updated with important software changes from upstream is too high # The cost to productize and deploy a newly released version is too high # Lack of tests to cover all scenarios means that a new public release cannot be immediately deployed to the field # Some aspects like documentation, code analysis reports, test reports and long term availability of tools are not available **Expectations from LTS** There is interest from the community to explore the possibility of a long-term release codebase to solve these problems. The following are the expectations from a long-term support release branch. # Stable and well-tested code branch # Well-defined criteria to pick changes for merge # High quality bar for every patch that gets merged # Active support from the maintainers for a minimum of five years # Clear communication of important milestones to the community **First LTS branch** The LTS topic was [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/ZZ2DDIW2DS4B7QYHYOL7XE4IPUW7LUNT/ | rebooted ]] in the community in May'22. A [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/MT37NYU3PFDLF5F6CRCRJRGD2SMY5BT3/ | proposal ]] was created by @okash and @vwadekar and presented to the community in a tech forum. The recording can be found at https://www.trustedfirmware.org/meetings/tf-a-technical-forum/. Thanks to the response from the community, the proposal has now evolved into an execution plan for the first LTS branch. The detailed plan is [[ https://developer.trustedfirmware.org/F274534 | attached ]]. `Points to note:` # The first LTS release will be created from TF-A v2.8 and released in Feb 2023. # The branch name will be based on the format: //lts-<base tf-a version>.<rolling minor version>//. e.g. lts-2.8.0 for the first branch # The branch maintainers plan to introduce a new mailing list (`tf-a-lts@lists.trustedfirmware.org`) to engage with the community. We expect the mailing list to be used for announcements, to report issues, to propose changes to cherry-pick, to propose policy changes, to provide feedback, etc. **Call to action** Reviewers are encouraged to review the plan and provide feedback. We request more people to try the LTS release when available and make the project a success. **References** - Tech forum discussion (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 10 Sep, 2020. - Tech forum discussions (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 14 July, 2022 and 8 Sep 2022. - LTS branch creation and execution proposal - https://developer.trustedfirmware.org/F274534

//**This page is under construction**// **Overview** An important criterion for evaluating and adopting a software platform is support. The Trusted Firmware-A community has been releasing code from the tip every six months. This model works very well for software innovation and implementing new hardware features. But for platforms in production, this policy does not scale in terms of maintenance, backward compatibility of important software fixes, getting latest security mitigations, and overall product lifecycle management. Several open-source software projects (e.g. Ubuntu, Yocto, Linux Kernel) have faced this problem during their lifetime and have implemented a long-term support release as a solution. Long-term support not only extends the period of software maintenance;, itbut also alters the type and frequency of software updates (patches) to reduce the risk, expense, and disruption of software deployment, while promoting the dependability of the software. It does not necessarily imply technical support. This document proposes a plan to leverage the path chosen by various open source software projects and define a long-term support release strategy.Long-term support is needed for commercial reasons too. More specifically, on the device side, when a product is released, the companies must support it such that the number of changes to the firmware are kept to a minimum to avoid the risk of regression. At the same time, the companies don't want to exclude critical patches such as those for security advisories. Similarly on server side, companies want to minimize the churn when deploying fixes during incident response, e.g. due to critical security bugs. This means that those companies must maintain and backport critical updates to old branches internally. As this effort is duplicated across different companies using TF-A, This proposal will not succeed without the support of the community and relies on contributions from Arm,it makes sense to factor out this effort into a community wide LTS effort. This document proposes a plan to leverage the path chosen by various open-source software projects and define a long-term support release strategy. its partnersThis proposal will not succeed without the support of the community and platform ownersrelies on their contributions. **Current problems** The following are some of the problems slowing down device upgrades. # The investment to maintain a software release and keep it updated with important software changes from upstream is too high # The cost to productize and deploy a newly released version is too high # Lack of tests to cover all scenarios means that a new public release cannot be immediately deployed to the field # Some aspects like documentation, code analysis reports, test reports and long term availability of tools are not available The technical forum for TF-A on 10 Sep, 2020 was focused on this topic to gauge interest and support from the community. To move the discussion forward, this page intends to capture ideas from the community and eventually crystalize a plan that works for everyone.**Expectations from LTS** **Expectations from LTS codebase** There is interest from the community to explore the possibility of a long-term release codebase to solve these problems. The following might be some ofare the expectations from a long-term support release branch. # Well defined policy to detect, report and deploy software fixes for mitigating security issues, stability concerns, erratas and bugsStable and well-tested code branch # 100% test coverage with a publicly available report# Well-defined criteria to pick changes for every changelistmerge # Up-to-date API reference manual at any given changelist# High quality bar for every patch that gets merged # Well documented performance numb# Active support from the maintainers for important use casesa minimum of five years # Usage of Long-term supported toolchainsClear communication of important milestones to the community **First LTS branch** The LTS topic was [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/ZZ2DDIW2DS4B7QYHYOL7XE4IPUW7LUNT/ | rebooted ]] in the community in May'22. A [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/MT37NYU3PFDLF5F6CRCRJRGD2SMY5BT3/ | proposal ]] was created by @okash and @vwadekar and presented to the community in a tech forum. The recording can be found at https://www.trustedfirmware.org/meetings/tf-a-technical-forum/. Thanks to the response from the community, the proposal has now evolved into an execution plan for the first LTS branch. The detailed plan is [[ https://developer.trustedfirmware.org/F274534 | attached ]]. `Points to note:` # Well defined policy for accepting new changes# The first LTS release will be created from TF-A v2.8 and released in Feb 2023. # Use of publicly available static analysis tools to improve code qualityThe branch name will be based on the format: //lts-<base tf-a version>.<rolling minor version>//. e.g. lts-2.8.0 for the first branch # Well defined release cadence and key quality indicators **Path to first LTS** The LTS topic was [[ https://lists.trustedfirmware.org/archives/list/tf-aThe branch maintainers plan to introduce a new mailing list (`tf-a-lts@lists.trustedfirmware.org/thread/ZZ2DDIW2DS4B7QYHYOL7XE4IPUW7LUNT/ | rebooted ]] inorg`) to engage with the community in May'22y. A [[ https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/MT37NYU3PFDLF5F6CRCRJRGD2SMY5BT3/ | proposal ]] was created by @okash and @vwadekar and presented to the community in a tech forum.We expect the mailing list to be used for announcements, The recording can be found at https://www.trustedfirmware.org/meetings/tf-a-technical-forum/. Thanks to the response from the community the proposal has now evolved into an execution plan for the first LTS branch.to report issues, to propose changes to cherry-pick, A stake in the ground is to release the first LTS branch in Feb'23.to propose policy changes, The detailed proposal is [[ https://developer.trustedfirmware.org/F274534 | attached ]]to provide feedback, etc. **Call to action** Reviewers are encouraged to review the proposalplan and provide feedback. We request more people to try the LTS release when available and make the project a success. **References** - Tech forum discussion (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 10 Sep, 2020. - Tech forum discussions (https://www.trustedfirmware.org/meetings/tf-a-technical-forum/) on 14 July, 2022 and 8 Sep 2022. - LTS branch creation and execution proposal - https://developer.trustedfirmware.org/F274534