• Linus Torvalds's avatar
    Make the "word-at-a-time" helper functions more commonly usable · f68e556e
    Linus Torvalds authored
    I have a new optimized x86 "strncpy_from_user()" that will use these
    same helper functions for all the same reasons the name lookup code uses
    them.  This is preparation for that.
    This moves them into an architecture-specific header file.  It's
    architecture-specific for two reasons:
     - some of the functions are likely to want architecture-specific
       implementations.  Even if the current code happens to be "generic" in
       the sense that it should work on any little-endian machine, it's
       likely that the "multiply by a big constant and shift" implementation
       is less than optimal for an architecture that has a guaranteed fast
       bit count instruction, for example.
     - I expect that if architectures like sparc want to start playing
       around with this, we'll need to abstract out a few more details (in
       particular the actual unaligned accesses).  So we're likely to have
       more architecture-specific stuff if non-x86 architectures start using
       (and if it turns out that non-x86 architectures don't start using
       this, then having it in an architecture-specific header is still the
       right thing to do, of course)
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>