On 28/10/2019 23.49, Luc Van Oostenryck wrote: > On Mon, Oct 28, 2019 at 08:32:42PM +0100, Rasmus Villemoes wrote: >> Hi, >> >> I just spent some time trying to convert some so far PPC-only drivers to >> be more generic. One of the things I had to do was convert stuff like >> >> u32 *val = of_get_property(np, "bla", NULL); >> do_stuff_with(*val); >> >> with >> >> of_property_read_u32(np, "bla", &val); >> do_stuff_with(val); >> >> (error checking omitted for simplicity). The problem is that >> of_get_property() just returns void*. When the property is just a >> string, there's no problem interpreting that as a char*. But when the >> property is a number of array of numbers, I'd like some way to flag >> casting it to u32* as an error - if you cast it to a (pointer to integer >> type wider than char), it must be to a __be32*. Is there some way >> sparse/smatch could help find such cases? > > If I understand you correctly, you would need a kind of 'soft' > bitwise pointer? Yes, that's a very good way of putting it. > I guess it shouldn't be too hard to add a new flag which would > allow cast of bitwise pointers to pointers to char/void (see > at end of evaluate.c:evaluate_cast()). Hm, yeah, but it should also allow casting to __be32* , but not u32* or __le32* (though somebody must have gone out of their way to introduce a bug in the latter case). Don't spend too much time on it, I was just wondering if there was an easy (maybe already existing) way. Thanks, Rasmus
