x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps

x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps

The protection key can now be just as important as read/write
permissions on a VMA.  We need some debug mechanism to help
figure out if it is in play.  smaps seems like a logical
place to expose it.

arch/x86/kernel/setup.c is a bit of a weirdo place to put
this code, but it already had seq_file.h and there was not
a much better existing place to put it.

We also use no #ifdef.  If protection keys is .config'd out we
will effectively get the same function as if we used the weak
generic function.

Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Laurent Dufour <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Mark Williamson <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>