[PATCH] kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurations

[Andrew Morton]

On Tue, 28 Feb 2012 09:19:28 +0900
Simon Horman <horms at verge.net.au> wrote:

> > > --- a/kernel/kexec.c
> > > +++ b/kernel/kexec.c
> > > @@ -1462,7 +1462,9 @@ static int __init crash_save_vmcoreinfo_init(void)
> > >  
> > >  	VMCOREINFO_SYMBOL(init_uts_ns);
> > >  	VMCOREINFO_SYMBOL(node_online_map);
> > > +#ifdef CONFIG_MMU
> > >  	VMCOREINFO_SYMBOL(swapper_pg_dir);
> > > +#endif
> > >  	VMCOREINFO_SYMBOL(_stext);
> > >  	VMCOREINFO_SYMBOL(vmlist);
> > 
> > Well, what might be the effects of this patch?  nommu crashfiles will
> > no longer have the swapper_pg_dir string?  What are the chances that
> > someone's (badly written!) downstream tool will crash and burn if this
> > is absent?
> 
> My understanding is that up until this patch creating a dump
> for nonmmu platform wouldn't work.

Surprised.  From reading the code I expect it would have emitted 

	SYMBOL(swapper_pg_dir)=0

?