The Linux kernel maintainers have taken the decision to go ahead with dropping support for old CPU architectures in an upcoming release. As a result, Linux 4.17 kernel will ship with a whopping 500,000 fewer lines of code – currently it contains around 20.3 million lines of code, according to Linux Counter.
The architectures which will become deprecated are Blackfin, CRIS, FRV, M32R, Metag, MN10300, Score and Tile. Although not being deprecated, the Unicore32 and Hexagon architectures are also at risk but their maintainers are working on improving the situation so their support can be continued.
Kernel developer, Arnd Bergmann posted to the Linux Kernel Mailing List saying:
“This [pull request] removes the entire architecture code for blackfin, cris, frv, m32r, metag, mn10300, score, and tile, including the associated device drivers.
I have been working with the (former) maintainers for each one to ensure that my interpretation was right and the code is definitely unused in mainline kernels. Many had fond memories of working on the respective ports to start with and getting them included in upstream, but also saw no point in keeping the port alive without any users.”
Killing off support for these architectures is beneficial for a few reasons, it’ll reduce the size of the kernel and it could also reduce the amount of attack vectors within the kernel if there were any bugs lurking.