[RFC][PATCH 0/8] x86/mm: page fault handling cleanups

[Dave Hansen]

I went trying to clean up the spurious protection key checks.
But, I got distracted by some other warts in the code.  I hope this
makes things more comprehendable with some improved structure,
commenting and naming.

We come out the other side of it with a new warning in for pkey
faults in the kernel portion of the address space, and removal
of some dead pkeys code, but no other functional changes.

There is a potential impact from moving the vsyscall emulation.
But, this does pass the x86 selftests without any fuss.

Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx