The new version 5.4 of the Linux kernel has just been released and as with previous versions, Several new features and improvements have been added in this new version of Linux. Of this a lock mode is highlighted that has been added to the kernel.
This lock mode strengthens the boundary between UID 0 (the root user) and the kernel. In practice, when this lockout mode is enabled, various functions are restricted. Applications that depend, for example, on low-level hardware or kernel access may no longer work. That is why it must be used very carefully or rather know what is done by activating it.
This feature has been implemented to ensure compliance with system protection that, in principle, ensures that we have a safe boot environment.
Another new feature outstanding is virtio-fs, a virtio driver based on FUSE to share files between the guest and the host (for virtualized environments). It also allows a guest to mount an exported directory on the host. One of the benefits of virtio-fs is that it takes advantage of virtual machine proximity to bring API performance closer to local file systems.
Another feature in Linux 5.4 is fs-verity is a support layer that file systems they can use to detect file spoofing, like dm-verity. However, it works on files rather than block devices. At present, it supports both ext4 and f2fs file systems.
As another novelty, too we have dm-clone it is a device mapper target that produces a copy one by one from an existing read-only source device to a write target device.
In fact, it features a virtual block device that displays all data immediately and redirects reads and writes accordingly. As a use case, dm-clone can be used to clone a read-only locking device, high latency and potentially remote in a writeable, fast core type device that enables Fast I / O, low latency. The cloned device is immediately visible or mountable and the copy of the source device on the target device is
For systems using the EROFS file system, it should be noted that this version 5.4 move filesystem out of staging area. Originally included in Linux 4.9, EROFS is a modern lightweight read-only and read-only file system designed for scenarios that require high read-only performance such as firmware on a mobile phone or Livecds. Similarly, the exFAT file system has been placed in the staging area.
We also have in this latest version of Linux a new controller and a haltpoll cpuidle governor. Dramatically improves the performance of virtualized guests who want to poll the guest in the idle loop.
In addition to these improvements, there is also support for four new products added to the amdgpu driver. This release also includes the first elements to support the future Intel Tiger Lake graphics processor.
In the experimental section, an open exFAT driver developed by Samsung is added. Previously, it was not possible to add exFAT support to the kernel due to patents, but the situation changed after Microsoft publish the publicly available specs and allow exFAT patents to be used for free on Linux.
The driver added to the kernel is based on outdated Samsung code (version 1.2.9), which requires refinement and adaptation to the requirements to design the code for the kernel.
After adding an outdated controller, enthusiasts they carried the new Samsung driver (sdFAT 2.x) used in Samsung Android firmware.
Later, Samsung independently decided to start promoting the new sdfat driver in the main Linux kernel. Additionally, Paragon Software has released an alternate controller previously shipped with a proprietary driver package.
Of the other changes in this new version of the Kernel these can be known In the following link.