There are a few new features in the Linux kernel 5.14 release, including support for IPv6 and improved performance when using the mmap() system call. Other new features include a new security feature called “perf_event”, which can be used to measure performance degradation caused by various system calls, and a new debugging tool called “debugfs”.
Birthday Celebrations and a New Kernel
Linux just turned 30. Linus Torvalds’ famous post about creating a free operating system (“…just a hobby, won’t be big and professional like GNU“) was made on August 25, 1991. A new Linux kernel was released at the end of August 2021, coinciding with the “constant glitz, the fireworks, and the champagne” that Torvalds dryly concludes will surely mark the passing of the intervening three decades.
This kernel release brings a varied collection of improvements and changes, mixing the usual bug fixes and performance improvements with features catering for some rather specific use-cases like better support for particular types of hardware and hot-unplugging for certain graphics cards.
One man’s niche is another man’s mainstream. Someone somewhere is going to be glad to see even the most esoteric addition or fix. Supporting more hardware platforms helps Linux spread, which can only be a good thing in the wider scheme of things. That being said, there’s plenty in this release that benefits everybody.
The one change that you might already have heard about isn’t one of the new additions, it’s something that has been taken out. Several tens of thousands of lines of legacy code have been removed from the kernel, and with it, support for the old and deprecated integrated drive electronics (IDE) hard drive interface.
So, support for a hardware interface that dates back to the late 1980s has been dropped, but what’s new in this release for the here-and-now?
Improved Laptop Feature Integration
Laptops from some manufacturers will benefit from dedicated features in kernel 5.14. Some of these are visible to the average end-user and some are behind the scenes. Lenovo ThinkPad laptop users can now change BIOS settings from within Linux.
This builds on an initiative spearheaded by Dell, that has also contributed a driver that permits the disablement of webcams and microphones by mimicking the action of a kill switch or the manufacturer-specific keyboard shortcut that does the same.
Improved Processor Support
Intel’s P-state hybrid architecture processors the Alder Lake P and Alder Lake M receive extended support. These processors feature a mix of high-performance “Golden Cove” and high-efficiency “Gracemont” cores. Not to be left out, support has been added for AMD’s Yellow Carp GPU and Beige Goby GPU.
Probably the most significant processor-related kernel enhancements are the memfd_secret and core scheduling improvements. These are part of the ongoing initiative against Intel’s previous Spectre and Meltdown vulnerabilities. These were discovered in 2018, and work has been ongoing since then to overcome these serious security flaws.
The memfd_secret feature lets applications allocate and ring-fence memory that even the kernel cannot access. This gives applications a safe place to store secrets such as encryption keys and authentication credentials.
The core scheduling methods let the kernel use hyper-threading more efficiently. It can now make sure high-trusted and low-trust processes don’t run on the same core at the same time. Previous methods to combat Spectre and Meltdown were to disable hyper-threading. Obviously, that was a stop-gap solution, and we’re seeing the real fixes coming through.
The RISC-V architecture gets enhanced support in the form of improved access to some core kernel features, including transparent hugepages. This is a kernel feature that improves performance by making the most efficient use of a CPU’s memory-mapping facilities. These are bolstered with optimized routines to move data back and forth between kernel space to userspace. The addition of SimpleDRM—in this context, “direct rendering manager” not “digital rights management”—improves interactions with GPUs.
USB4 Improvements
The kernel’s USB4 routines have been improved. The latency of its audio drivers has been reduced, and improvements and bug fixes have been added to many other USB-related drivers. The support of USB4 in the thunderbolt core has been updated and increased.
AMD Radeon Hot-Swapping Support
Fancy pulling your AMD Radeon graphics card out of your computer while it is running? Theoretically, with kernel 5.14 you can now do so, and without getting a kernel panic for your efforts. This might be a little-looked-for feature, but the AMD Radeon GPUs support this feature and so the kernel now supports it.
Support for Other Platforms
Support has been improved for platforms outside of the standard PC form factor. The Raspberry Pi 400 is a computer inside a keyboard. Based on model 4 of the popular Raspberry Pi single-board computer (SBC) much favored by hobbyists, makers, and educators it packs a very affordable computer into a package smaller than a standard keyboard. However, the non-standard hardware required a custom kernel. Support is now included within the standard kernel.
The Banana Pi is a cheekily-named direct competitor to the Raspberry Pi. The Banana Pi Model M now gets direct support within the kernel.
Systems-on-a-chip have also received attention. Adding direct support for the Qualcomm SM8150 system-on-a-chip (SoC) improves the user experience for Linux users leveraging the Microsoft Surface Duo platform that is based on this SoC. SM8150 is the part number for the Snapdragon 855+/860 mobile platform.
The Rockchip RK3568 SoC is also supported by kernel 5.14. This is a product designed to be used by other manufacturers inside their own products. Interestingly, it is being tested on the Quartz64. This is an SBC that’s being developed by Pine64, the people behind the Linux-based PinePhone.
On the topic of smartphones, support has also been added for the Sony Xperia 1/1II and 5/5II smartphones, easing their use with operating systems such as Ubuntu Touch.
When Will My Distribution Get 5.14?
Rolling distributions like Arch and Manjaro are already updating themselves to 5.14. Other distributions will follow suit according to their own upgrade and update cycles. it’s great to see ever-wider and better support for platforms other than standard desktops and servers. This benefits the Linux community as a whole, not just the users of non-mainline platforms.
Oh yeah, happy birthday, Linux!
