After two months of development, Linus Torvalds announced the release of Linux kernel 5.12, version in which the most notable changes include support for zoned block devices in Btrfs, the ability to map user IDs to file systems, KFENCE debugging system to detect errors when working with memory, among others.
The new version received 14170 fixes from 1946 developers, the patch size is 38MB (changes affected files 12102 (12090), added 538599 (868025) lines of code, removed 333377 (261456) lines).
Main news in Linux 5.12
The ability to map user IDs for mounted file systems has been implemented. The mapping is compatible with FS FAT, ext4 and XFS, whereby the proposed functionality makes it easier to share files between different users and on different computers, including the mapping to be used in the systemd-homed home directory mechanism.
Another novelty is that the file system Btrfs adds initial support for zoned block devices. In read-only mode, support is provided for blocks with metadata and data that are smaller than one page (subpage).
It is also highlighted that the ability to build the kernel with the Clang compiler was implemented with the inclusion of optimizations in the link stage (LTO, Link Time Optimization). For example, with LTO, inline deployment is possible for functions from other files, unused code is not included in the executable file, type checking and general optimization are carried out at the project level as a whole. LTO support is currently limited to the x86 and ARM64 architectures.
Also added nvmem driver to receive data from memory areas reserved by firmware that are not directly accessible to Linux (for example, EEPROM memory physically accessible only for firmware or data available only at an early stage of loading).
On the other hand, it is highlighted that KFence protection mechanism has been added (Kernel Electric Fence), which detects errors when working with memory, such as buffer overflows and access after freeing up memory. Unlike the KASAN debugging mechanism, the subsystem KFence is distinguished by its high speed and low overhead costs, allowing you to detect memory errors that appear only in running systems or during long-term operation.
The Integrity Measurement Architecture (IMA) subsystem, which maintains a database of hashes to verify the integrity of files and their associated metadata, now has the ability to verify the integrity of the kernel's own data, for example to track changes in SELinux rules.
The hypervisor KVM now has the ability to intercept Xen hypercalls and forward them to the user space emulator.
Added the ability to use Linux as the root environment for the Hyper-V hypervisor as it has direct hardware access and is used to run guest systems (similar to Dom0 on Xen). Until now, Hyper-V (Microsoft Hypervisor) only supported Linux in guest environments, but the hypervisor itself was managed from a Windows-based environment.
The controller amdgpu implements the ability to overclock (OverDrive)tSienna Cichlid GPU-based cards (Navi 22, Radeon RX 6xxx).
The controller i915 for Intel Graphics implements the i915.mitigations parameter to disable isolation and protection mechanisms in favor of better performance. For chips starting from Tiger Lake, support for VRR mechanism included (Variable Rate Refresh), which allows you to adaptively change the refresh rate of the monitor to ensure smoothness and the absence of breaks during games. Includes support for Intel Clear Color Technology to improve color accuracy.
The controller Nouveau Adds Initial Support for NVIDIA GPUs Based on the GA100 Architecture (Ampere). The msm driver adds support for the Adreno 508, 509, and 512 GPUs used in the SDM (Snapdragon) 630, 636, and 660 chips.
Added support for Sound BlasterX AE-5 Plus, Lexicon I-ONIX FW810s, and Pioneer DJM-750 sound cards. Added support for the Intel Alder Lake PCH-P audio subsystem.
Also, also in this new version of Linux 5.12 Support for Nintendo 64 game consoles has been made official manufactured between 1996 and 2003 (previous attempts to port Linux to Nintendo 64 were incomplete and had Vaporware status).
Added support for Lenovo IdeaPad platform with the ability to manage constant load and keyboard backlighting. It also supports the ACPI profile of the ThinkPad platform with power management capabilities. Added driver for Lenovo ThinkPad X1 Tablet Gen 2 HID subsystem.
Added support for ARM boards, devices and platforms: PineTab, Snapdragon 888 / SM8350, Snapdragon MTP, Two Beacon EmbeddedWorks, Intel eASIC N5X, Netgear R8000P, Plymovent M2M, Beacon i.MX8M Nano, NanoPi M4B.
Source: https://lkml.org