Re: [RESEND PATCH V3 2/2] riscv: add RISC-V Svpbmt extension supports

[Wei Fu]

Hi Chistoph,

On Tue, Nov 2, 2021 at 2:07 PM Christoph Hellwig <hch@xxxxxx> wrote:
>
> On Mon, Oct 25, 2021 at 06:55:09PM +0800, Wei Fu wrote:
> > How about this macro:
> > #define _SVPBMT_PMA         0x0UL
> > #define _SVPBMT_NC         BIT(61)
> > #define _SVPBMT_IO         BIT(62)
> > #define _SVPBMT_MASK         GENMASK(62, 61)
>
> Personally I find these macros highly confusing.
>
> #define _SVPBMT_PMA     0UL
> #define _SVPBMT_NC      (1UL << 61)
> #define _SVPBMT_IO      (1UL << 62).
> #define _SVPBMT_MASK    (_SVPBMT_NC  | _SVPBMT_IO)
>
> is much eaier to follow.  Note that we can probably just drop
> _SVPBMT_PMA entirely to make this even more readable.

sure, I can do this , thanks

>
> > > Also why not use the standard names for these _PAGE bits used by
> > > most other architectures?
> >
> > Which names are you suggesting? Would you mind providing an example ?
> > _PAGE_BIT_   for _PAGE_KERNEL_ ??
>
> Use _PAGE_NOCACHE for _SVPBMT_NC, and _PAGE_IO for _SVPBMT_IO.

OK, Sure , will do

Great thanks

>