Glibc Rolls Out Support For Memory Protection Keys

While kernel side there's been Memory Protection Keys support since Linux 4.9 and work has already landed in GCC and Clang, the glibc GNU C Library is finally adding support for MPK.

Memory Protection Keys premiered with Intel Xeon Scalable CPUs and will be coming to desktop Intel CPUs in the future. This feature allow for enforcing page-based memory protections via the RDPKRU/WRPKRU instructions.

Thanks to work by Red Hat's Florian Weimer, the memory protection keys interfaces have been added to Glibc for pkey_alloc/pkey_free/pkey_mprotect.

Details in this commit. This functionality will be found in the eventual glibc 2.27 release.