Re: [PATCH v3 11/11] s390/percpu: Rework to simplify percpu_entry() and percpu_exit()

[Mark Rutland]

On Mon, Sep 21, 2026 at 10:55:18AM +0100, David Laight wrote:
> On Mon, 21 Sep 2026 10:40:05 +0200
> Heiko Carstens <hca@xxxxxxxxxxxxx> wrote:

> > +	regpcp = FIELD_GET(PCPU_REG_PCP, regval);
> > +	regoff = FIELD_GET(PCPU_REG_OFF, regval);
> ...
> > +#define PCPU_REG_PCP_SHIFT		0
> > +#define PCPU_REG_PCP			GENMASK(3, 0)
> > +#define PCPU_REG_OFF_SHIFT		4
> > +#define PCPU_REG_OFF			GENMASK(7, 4)
> ...
> > +#define __PCPU_CALC_REGVAL(regpcp, regoff)					\
> > +	"(" regpcp " << " __stringify(PCPU_REG_PCP_SHIFT) ") |"			\
> > +	"(" regoff " << " __stringify(PCPU_REG_OFF_SHIFT) ")"
> 
> I'm not a big fan of GENMASK() + FIELD_GET() and I'm not at all sure it
> really helps here.

It's the same pattern already used by the extable code. 

While _you_ don't like it, that's not a universal opinion (and FWIW, I
prefer the FIELD_GET() approach).

I'll leave it to Heiko and co to choose whatever style they prefer, as
it's their architecture port...

Mark.