[PATCH] ARM: Add SWP/SWPB emulation for ARMv7 processors

[Jamie Lokier]

Woodruff, Richard wrote:
> Exclusive operations are more certainly more efficient than the full
> bus lock behavior of SWP.  Finding and killing SWP where possible
> seems positive.

Are they really more efficient for cached accesses in L1?  In
principle, external bus lock is not needed when doing an
read-modify-write on words in MESI cache, just the ability to
internally block it's eviction during the sequence.

-- Jamie