Re: Testing of function/data-sections on linux-2.6.35-rc4

Sam Ravnborg
2010-07-26T07:28:28Z

On Mon, Jul 26, 2010 at 03:31:34AM +0200, Denys Vlasenko wrote:
> Hi Sam,
>
> On Friday 23 July 2010 22:35, Sam Ravnborg wrote:
> > >
> > > Then, in order to also garbage-collect the sections, I added
> > >
> > > LDFLAGS_vmlinux += --gc-sections
> > >
> > > in top-level Makefile.
> > >
> > > This requires the additional patch (linux-2.6.35-rc4-fsgs.patch)
> > > which adds KEEP(section) directives to kernel linker stripts.
> > > Otherwise, linker will discard some crucial sections.
> > >
> >
> > Changelog does not address why you need:
> >
> > -Map $@.ldmap
> >
> > and what effect they have.
>
> I didn't plan to push the last step (--gc-sections) to mainline yet.
> Thus the patch has debugging stuff in it.
>
>
> > And it is obvious that some archs should consolidate a little more from
> > asm-generic/vmlinux.lds.h.
> > But that said this patch looks much better than the initial versions posted.
> >
> > How do you determine which sections needs the KEEP()?
> > Worth documenting for future when we add new sections.
>
> No problem, I will be adding comments at every KEEP() why it's needed.

A general comment in vmlinux.lds.h and a careful explanation
in the changelog should be enough.

You should not comment each of the KEEP().

Sam