[PATCH v7 1/6] riscv: mm: dma-noncoherent: Switch using function pointers for cache management

Christoph Hellwig hch at infradead.org
Thu Apr 6 22:33:32 PDT 2023


On Fri, Apr 07, 2023 at 02:03:36AM +0200, Andrea Parri wrote:
> > But other other point is adding more cache flushing variants should not
> > be easy.  Everyone should be using the standardize version.  If it's not
> > implemented in hardware despite having ratified extensions you can fake
> > it up in SBI.  Yes, that's way more expensive than indirect calls, but
> > that's what you get for taping out new hardware that ignores the actual
> > architecture specification and just does their own made up shit.
> 
> FWIW, ALTERNATIVE_X() for "three instructions with (what should be a)
> crystal-clear semantics" already smells like "we're doing it wrong" to
> me, function pointers would be closer to "we're looking for trouble".

Thanks for putting my feelings into such concise words.



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