Lockdown comes locked by default and allows two lock modes: integrity and confidentiality. The first provides a full block, so it is impossible to make any modification in the kernel. The second adds one more limitation: all functions that allow to extract confidential information about the kernel are also totally blocked.
Another highlight of Linux 5.4 is the native support of exFAT, the new Microsoft file system that accelerates file transfer, even with large multimedia files.
In addition, graphics performance has been improved by adding support for AMD Radeon Navi 12 and 14 GPUs, AMD Radeon Arcturus GPUs and AMU Dali APU.
Support has also been improved by adding new functions and features for AMD Ryzen 3000 series CPUs and AMD EPYC microprocessors.
Among the rest of the Linux 5.4 enhancements are the compatibility with Intel Tiger Lake CPUs, Qualcomm Snapdragon 855 SoCs, support for Intel Lightning Mountain SoC, improved application memory management on Android and a new high-performance virtio controller to share files.