Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures

[Segher Boessenkool]

> > And no, RMW on MMIO isn't "problematic" at all, either.
> >
> > An RMW op is a read op, a modify op, and a write op, all rolled
> > into one opcode.  But three actual operations.
>
> Maybe for some CPUs, but not all.  ARM for instance can't use the
> load exclusive and store exclusive instructions to MMIO space.

Sure, your CPU doesn't have RMW instructions -- how to emulate
those if you don't have them is a totally different thing.


Segher

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