Linux 5.9 Exposes Device Link Details Via Sysfs, Allows Hiding DebugFS From User-Space

There are a few driver core changes for the Linux 5.9 kernel worth mentioning.

Exciting changes to the core driver infrastructure for the mainline Linux kernel are rare though this time around are a few alterations worth pointing out:

- The recently covered work by Sony on being able to allow restricting user-space access to DebugFS while keeping the debug feature enabled is in Linux 5.9. While most distributions / Linux configurations already restrict DebugFS access to root / admin privileges, as this file-system often exposes sensitive system information, the change by Sony allows for it to be initialized but not accessible from user-space. Sony's focus on this effort appears to be in line of further securing their Android smartphones.

- Another change with Linux 5.9, this time by Google, is exposing of device link details under sysfs. This allows better mapping and understanding if one device is a supplier or consumer to another. Details on the exposed device topology under sysfs via this patch.

- There is now a device probe log helper so drivers can report problems in a more unified manner.

There are also other driver core changes as outlined via the pull request that is already merged to mainline Linux 5.9.