mm: untag user pointers in mm/gup.c

This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

mm/gup.c provides a kernel interface that accepts user addresses and
manipulates user pages directly (for example get_user_pages, that is used
by the futex syscall).  Since a user can provided tagged addresses, we
need to handle this case.

Add untagging to gup.c functions that use user addresses for vma lookups.

Link: http://lkml.kernel.org/r/4731bddba3c938658c10ff4ed55cc01c60f4c8f8.1563904656.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <[email protected]>
Reviewed-by: Khalid Aziz <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Eric Auger <[email protected]>
Cc: Felix Kuehling <[email protected]>
Cc: Jens Wiklander <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions