Re: Please include const-sections into linux-next

James Bottomley
2011-10-19T20:04:57Z

On Wed, 2011-10-19 at 21:05 +0200, Andi Kleen wrote:
> On Wed, Oct 19, 2011 at 01:55:57PM -0500, James Bottomley wrote:
> > On Wed, 2011-10-19 at 18:33 +0200, Andi Kleen wrote:
> > > > OK, look at it another way: why do we need the type annotations? I
> > > > think it's only for section conflict checking, right? If the compiler
> > > > gets it wrong anyway, why not just dump all the type annotations, then
> > > > it should have no type conflicts (spurious or otherwise) to complain
> > > > about. We already have link time section checking scripts (they're the
> > > > useless ones that complain about section mismatches in dev annoations)
> > > > so why not put them to work to make up for compiler deficiencies?
> > >
> > > You mean removing all the init sections stuff? I think it has been proposed
> > > in the past, but it's a couple of hundred KB of memory usually.
> > > Would you accept that for PA-RISC?
> > >
> > > If you have init sections you need to annotate them correctly because
> > > a section is defined by its rwx attributes plus name and both need
> > > to match. We didn't always check this, so there was some bitrot,
> > > but it ultimatively has to be correct.
> >
> > We're talking at cross purposes. But it doesn't matter, the error
> > doesn't seem to be anything to do with type. This simple patch is
> > what's causing it (I can apply it alone to the working tree) and get the
> > error.
> >
> > What I can't see is why.
>
> For some reason your compiler sets the const section read/write:
>
> .section .devinit.data,"aw",@progbits <---- writable
> .align 8
> .type skel_netdrv_tbl, @object
> .size skel_netdrv_tbl, 48
> skel_netdrv_tbl:
> ; chip_name:
> .dword .LC56
>
> while my x86 toolchain sets it to read only
>
> .string "1000/100/10M Ethernet PCI Adapter"
> .section .devinit.data,"a",@progbits <---- not writable
> .align 16
> .type skel_netdrv_tbl, @object
> .size skel_netdrv_tbl, 48

So most of our const stuff is "a" not "aw". However, this particular
list is a list of strings ... this is probably something to do with
writeable strings?

James