The strange story of the ARM Meltdown-fix backport

Keep in mind that Arm doesn't actually _make_ SoCs, be they large or small. They design and license out the CPU cores (along with GPUs and an assortment of other peripherals) but what pieces to use and how they're tied together is up to their customers/licensees.

Over time Arm has provided more and more building blocks, including reference designs, and have increasingly encouraged more standardization in how things are put together (The Cortex-M's CMSIS framework is a good example, along with the SBSA stuff for the ARMv8 servers) but it's still ultimately up to the licensee to put together and support an appropriate CSP/BSP. Because the many licensees typically end up differentiating themselves into corners, things tend to fall apart rapidly, resulting in the current less-than-ideal situation.