Linus Torvalds has closed the merge window for Linux 5.13 with the first release candidate, which includes initial support for Apple's M1 processor along with "a fair amount of stuff, all over the place."
The closing of the merge window means that the new code which has been accepted by the Linux development community as both desirable and sufficiently stable is included in the first release candidate for the new kernel, which is generally feature-complete. The work is now focused on stability and fixing problems, ahead of the stable release which usually follows within a couple of months.
On this occasion Torvalds said that "there's a lot in there," of which a third is auto-generated from hardware descriptions and 60 per cent driver changes. That still leaves room for a number of significant new features. Overall, there are 12,015 files changes, 631,309 insertions, and 246,239 deletions.
The changes include initial support for Apple M1 processors, based on the work of Arnd Bergmann, Hector Martin, and others.
Martin said: "This is just basic bring-up, but it lays a solid foundation and is probably the most challenging upstreaming step we'll have to do, at lease until the GPU stuff is done."
There are also many changes to better support RISC-V, including the ability to build the kernel with FORTIFY_SOURCE, to detect buffer overflows.
Also included is support for KProbes, for collecting debugging and performance data from kernel modules, and for Execute In Place (XIP), allowing code to run from fast storage instead of being loaded into system memory.
Microsoft has added patches for running Linux as a Hyper-V guest on ARM64 – a capability which could be of value to its Azure cloud if the company introduces ARM64-based servers, as AWS has done with great success using its Graviton processor family.
There is also support for graphics, and performance counter support for Intel's Alder Lake, the 12th-generation Core processors whose launch is expected later this year, and for AMD Zen3 performance events.
A further bit of good news for Linux users is that version 5.10 now has confirmed long-term support until December 2026, rather than December 2022 as once threatened. This means that sufficient device vendors have stepped up to help, enabling the new date to be promised on the Linux releases page. ®