On Thu, 25 Aug 2011, James Bottomley wrote:

quoted

ARM seems to have these LDREX/STREX instructions for that purpose which
seem to be used for generating atomic instructions without lockes. I
guess
other RISC architectures have similar means of doing it?

Arm isn't really risc.  Most don't.  However even with ldrex/strex you need two instructions for rmw.

Well then what is "really risc"? RISC is an old beaten down marketing term
AFAICT and ARM claims it too.