Last year Wine itself added emulation for some CPU instructions now blocked by UMIP, the User-Mode Instruction Prevention functionality found in the latest Intel and AMD processors. Now slated for Linux 5.10 is the emulation/spoofing of two of those instructions by the kernel as another attempt to help a small number of Windows programs relying on those instructions.
Proposed last summer by Valve and Collabora developers were extending the Linux kernel’s futex system call to allow for more optimal thread pool synchronization and paired with Wine/Proton work to better match the semantics of Windows. That then spun into creating a new system call, futex2. With the recently closed Linux 5.9 merge window the new futex2 system call didn’t land, but the work is still being pursued.