On Friday, September 2, 2016 2:27:21 PM CEST Laura Abbott wrote:
> >
> > All warnings (new ones prefixed by >>):
> >
> > drivers/staging/android/ion/ion.c: In function 'ion_query_heaps':
> >>> drivers/staging/android/ion/ion.c:1181:3: warning: cast to pointer from
> >>> integer of different size [-Wint-to-pointer-cast]
> > (struct ion_heap_data __user *)query->heaps;
> > ^
> >
>
> botching-up-ioctls.txt says:
>
> * Pointers are __u64, cast from/to a uintprt_t on the userspace side and
> from/to a void __user * in the kernel. Try really hard not to delay this
> conversion or worse, fiddle the raw __u64 through your code since that
> diminishes the checking tools like sparse can provide.
>
> This doesn't seem like it will work on 32-bit systems since you'll end up
> with the warning above. Is there a better option or did I misunderstand
> how that is supposed to work?
>
I don't know a better way that two cast, doing
(struct ion_heap_data __user *)(uintptr_t)query->heaps;
It may help to put this into an inline function though.
Arnd
