[PATCH 28/31] x86, fpu: allow setting of XSAVE state

From: Dave Hansen We want to modify the Protection Key rights inside the kernel, so we need to change PKRU's contents. But, if we do a plain 'wrpkru', when we return to userspace we might do an XRSTOR and wipe out the kernel's 'wrpkru'. So, we need to go after PKRU in the xsave buffer. We do

[PATCH 28/31] x86, fpu: allow setting of XSAVE state

From: Dave Hansen We want to modify the Protection Key rights inside the kernel, so we need to change PKRU's contents. But, if we do a plain 'wrpkru', when we return to userspace we might do an XRSTOR and wipe out the kernel's 'wrpkru'. So, we need to go after PKRU in the xsave buffer. We do