Devices and platforms based on ARM architecture have become some of the most widely used platforms running Linux as it is used in a large number of mobile and embedded devices. In adopting Linux and open source projects many companies have evolved their working practises, moving from traditional closed development to using open source software components and contributing changes back to upstream projects to enable their platforms and build a strong developer community around them. Given that ARM is used in such a diverse range of platforms, the challenge for software developers and open source project maintainers has been to integrate and maintain contributions in an efficient way and limit code duplication to enable them to scale as the number of contributors increases. The Linux kernel has been a very visible example of this, with Linus Torvalds recently pushing back on contributions forcing some code refactoring and clean-up for redundant implementations. This talk with present the current status of Linux on ARM and how ARM and its partners are addressing these challenges to better support Linux kernel and upstream open source projects. In addition, ARM partners are contributing performance improvements to the Linux kernel and key open source projects to better perform on ARM CPU and platforms where there is a very strong focus on optimizing the balance between power usage and performance. This presentation will also highlight some of Linaro key contributions as a not-for-profit organization created to provide a framework for partners, and open source developers, to collaborate in developing and optimizing open source projects on ARM.