Hi Andy,
On Mon, Aug 21, 2023 at 5:25 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> On Mon, Aug 21, 2023 at 03:27:43PM +0200, Geert Uytterhoeven wrote:
> > On Mon, Aug 21, 2023 at 3:04 PM Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > > On Sun, Aug 20, 2023 at 07:44:00PM +0100, Biju Das wrote:
>
> ...
>
> > > For all your work likes this as I noted in the reply to Guenter that
> > > the couple of the selling points here are:
> > > 1) avoidance of the pointer abuse in OF table
> > > (we need that to be a valid pointer);
> >
> > There is no pointer abuse: both const void * (in e.g. of_device_id)
> > and kernel_ulong_t (in e.g. i2c_device_id) can be used by drivers
> > to store a magic cookie, being either a pointer, or an integer value.
> > The same is true for the various unsigned long and void * "driver_data"
> > fields in subsystem-specific driver structures.
>
> (void *)5 is the abuse of the pointer.
> We carry something which is not a valid pointer from kernel perspective.
But the data field is not required to be a valid pointer.
What kind and type of information it represents is specific to the driver.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
