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

Christoph Hellwig
2023-04-07T05:33:48Z

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.