Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1265368

Re: [PATCH] video: constify geode ops structures

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Sun, Nov 08, 2015 at 10:24:49PM +0000, Julia Lawall wrote:
> On Mon, 9 Nov 2015, Dan Carpenter wrote:
> 
> > Cool.  So, in grsec they use a GCC plugin to make these const
> > automatically since they only contain function pointers.  There about
> > 100 struct types marked as __no_const.  Kees would like to adopt the
> > grsec pluggin approach I expect.  Do you have an idea how many structs
> > only contain function pointers or how many consts we would have to add
> > to get the same effect without the plugin?
> 
> My list has 373 type names.  In the list there are counts for good
> (already const) and bad (not const).  The sum of the bad values is 2467.
> The list is below.
> 
> julia

Fantastic!  Thanks.  We could autogenerate the list of type names and
make checkpatch.pl complain if we declared those types as non const.

I ran this command to find which functions grsec marks as __no_const.

egrep '(^ struct |^@@|__no_const;)' grsecurity-3.1-4.2.5-201511021814.patch | grep __no_const -B1 | grep -v __no_const | grep -v '^--' | cut -d @ -f 5-  | cut -b 9- | cut -d ' ' -f 1

There are 60 structs declared as __no_const.  For some structs they
declare a no_const version and use it as needed.  Like this:
typedef struct net_device_ops __no_const net_device_ops_no_const;

grep __no_const grsecurity-3.1-4.2.5-201511021814.patch | grep typedef | cut -d ' ' -f 3

There are 32 of those.

Then I compared to see if their structs were on your list.  For some
reason there quite a few one their list which are not on yours.  Out
of the first 10 about half weren't on your list.  cpu_cache_fns,
outer_cache_fns, psci_operations, smp_operations, omap_hwmod_soc_ops,
smp_ops_t.  These are mostly different arches?

Also bit_table has in int has well as a function pointers but it is on
their list.  I'm not sure why.  Maybe they are marking structs const
that I don't know about.

The other trick that they do is they define structs as __do_const if
they want them to be const by default, which is pretty neat.  This feels
like it should be a standard GCC feature.  In the meantime we could
mark things as __do_const and print a sparse warning if it was declared
as not const.

I have attached the list of __no_const structs.

regards,
dan carpenter

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] video: constify geode ops structures Julia Lawall <Julia.Lawall@lip6.fr> - 2015-11-08 22:50 +0100
  Re: [PATCH] video: constify geode ops structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-08 23:20 +0100
    Re: [PATCH] video: constify geode ops structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-08 23:30 +0100
      Re: [PATCH] video: constify geode ops structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-09 06:50 +0100
        Re: [PATCH] video: constify geode ops structures Joe Perches <joe@perches.com> - 2015-11-09 07:10 +0100
        Re: [PATCH] video: constify geode ops structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-09 07:50 +0100
          Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-09 14:40 +0100
            Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-09 19:20 +0100
              Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Joe Perches <joe@perches.com> - 2015-11-09 19:20 +0100
        Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-09 15:00 +0100
          Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-09 16:00 +0100
            Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-09 17:40 +0100
            Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Emese Revfy <re.emese@gmail.com> - 2015-11-09 18:10 +0100
              Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-09 18:50 +0100
                Re: [kernel-hardening] Re: [PATCH] video: constify geode ops structures Kees Cook <keescook@chromium.org> - 2015-11-09 22:30 +0100
                Re: [kernel-hardening] Re: [PATCH] video: constify geode ops  structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-09 23:00 +0100
                Re: [kernel-hardening] Re: [PATCH] video: constify geode ops structures Kees Cook <keescook@chromium.org> - 2015-11-10 00:40 +0100
                Re: [kernel-hardening] Re: [PATCH] video: constify geode ops structures "PaX Team" <pageexec@freemail.hu> - 2015-11-10 02:40 +0100
        Re: [PATCH] video: constify geode ops structures Julia Lawall <julia.lawall@lip6.fr> - 2015-11-10 16:50 +0100
    Re: [PATCH] video: constify geode ops structures Kees Cook <keescook@chromium.org> - 2015-11-09 22:30 +0100
      Re: [PATCH] video: constify geode ops structures Christoph Hellwig <hch@infradead.org> - 2015-11-10 07:40 +0100
        Re: [PATCH] video: constify geode ops structures Kees Cook <keescook@chromium.org> - 2015-11-10 21:40 +0100
          Re: [PATCH] video: constify geode ops structures Joe Perches <joe@perches.com> - 2015-11-10 21:50 +0100
            Re: [PATCH] video: constify geode ops structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-10 23:10 +0100
              Re: [PATCH] video: constify geode ops structures Joe Perches <joe@perches.com> - 2015-11-10 23:20 +0100
                Re: [PATCH] video: constify geode ops structures Dan Carpenter <dan.carpenter@oracle.com> - 2015-11-10 23:40 +0100
                Re: [PATCH] video: constify geode ops structures Joe Perches <joe@perches.com> - 2015-11-10 23:50 +0100

csiph-web