From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Dan Carpenter <dan.carpenter@oracle.co>,
linux-sparse@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: detecting misuse of of_get_property
Date: Mon, 28 Oct 2019 23:49:15 +0100 [thread overview]
Message-ID: <20191028224914.enpqjkcvbxyeexnl@desk.local> (raw)
In-Reply-To: <ec277c12-c608-6326-7723-be8cab4f524a@rasmusvillemoes.dk>
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?
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()).
Note: casts from bitwise pointer to void* are already allowed.
-- Luc
next prev parent reply other threads:[~2019-10-28 22:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 19:32 detecting misuse of of_get_property Rasmus Villemoes
2019-10-28 22:49 ` Luc Van Oostenryck [this message]
2019-10-29 7:24 ` Rasmus Villemoes
2019-10-29 10:50 ` Dan Carpenter
2019-10-29 11:43 ` Rasmus Villemoes
2019-10-29 12:57 ` Dan Carpenter
2019-10-29 11:47 ` Luc Van Oostenryck
2019-10-29 12:55 ` Dan Carpenter
2019-10-29 13:37 ` Luc Van Oostenryck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191028224914.enpqjkcvbxyeexnl@desk.local \
--to=luc.vanoostenryck@gmail.com \
--cc=dan.carpenter@oracle.co \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-sparse@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).