[PATCH 5/5] arm64: atomics: lse: define RETURN ops in terms of FETCH ops

[Peter Zijlstra]

On Fri, Dec 10, 2021 at 03:14:10PM +0000, Mark Rutland wrote:
> The FEAT_LSE atomic instructions include LD* instructions which return
> the original value of a memory location can be used to directly
> implement FETCH opertations. Each RETURN op is implemented as a copy of
> the corresponding FETCH op with a trailing instruction instruction to

instruction instruction instruction is probably even more better :-)

> generate the new value of the memory location. We only
> directly implement *_fetch_add*(), for which we have a trailing `add`
> instruction.