arm64, mm: move generic mmap layout functions to mm

arm64 handles top-down mmap layout in a way that can be easily reused by
other architectures, so make it available in mm.  It then introduces a new
config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT that can be set by other
architectures to benefit from those functions.  Note that this new config
depends on MMU being enabled, if selected without MMU support, a warning
will be thrown.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexandre Ghiti <[email protected]>
Suggested-by: Christoph Hellwig <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Acked-by: Kees Cook <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Russell King <[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