Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '__iomem' of expression

From: Miquel Raynal
Date: Thu Nov 12 2020 - 03:27:24 EST


Hi Sergey,

Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote on Wed, 11 Nov
2020 22:22:59 +0300:

> On Tue, Nov 10, 2020 at 04:35:56PM +0100, Miquel Raynal wrote:
> > Hi Serge,
> >
> > Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote on Tue, 10 Nov
> > 2020 14:38:27 +0300:
> >
> > > Hello Miquel,
> > >
> > > A situation noted by the warning below won't cause any problem because
> > > the casting is done to a non-dereferenced variable. It is utilized
> > > as a pointer bias later in that function. Shall we just ignore the
> > > warning or still fix it somehow?
> >
>
> > Do you think the cast to a !__iomem value is mandatory here?
>
> It's not mandatory to have the casting with no __iomem, but wouldn't
> doing like this:
> + shift = (ssize_t __iomem)src & 0x3;
> be looking weird? Really, is there a good way to somehow extract the first
> two bits of a __iomem pointer without getting the sparse warning?

I asked around me, what about trying uintptr_t?

Thanks,
Miquèl