On Thu, 11 Aug 2016, Arnd Bergmann wrote:
> On Thursday, August 11, 2016 4:01:33 PM CEST Nicolas Pitre wrote:
> > > #ifdef CONFIG_SMP_ON_UP
> > > .init.smpalt : {
> > > __smpalt_begin = .;
> > > - *(.alt.smp.init)
> > > + KEEP(*(.alt.smp.init))
> >
> > Yes unfortunately this needs a KEEP() right now as there is no explicit
> > references to those entries. But by doing so you force a reference from
> > those entries to all functions they annotate, preventing those functions
> > from being discarded if there isn't any reference to that code
> > otherwise. That's a case that falls into the "missing forward reference"
> > category in my slides.
>
> I see. This actually relates to an existing problem with SMP alternatives
> in exit sections, which cause a linker error. I've done a patch for
> this at some point, but didn't feel confident enough to send it out
The only sane way I found to solve this implied a patch to gas, and it
was accepted upstream. Please see:
http://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=451133cefa
The example given is for .init sections, but that would solve the
link-time discarding of .exit sections just as well.
Nicolas
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