Gerd Hoffmann wrote:

[ depending on CONFIG_SMP ]

>> Okay, thanks. Yes, I agree such would make sense.
> 
> Patch below.  It simply returns in case the tables are empty and nothing
> is do to, thus avoids printing the confusing message.

It does avoid the message but well, that's also _all_ it avoids. Why do 
you want to do it this way? If I apply the attached, things compile and 
work fine which seems to confirm that, yes, all this smp_alternatives 
code is simply dead baggage on !CONFIG_SMP.

Yes, the #ifdef in arch/i386/kernel/module.c is a bit clumsy. Just proof 
of concept, might be abstracted out a bit better. It does lose most of 
alternatives.c which would seem to be good thing.

Unless I'm missing some points, I believe this code should not be 
compiled in for !CONFIG_SMP.

One other point, although probably not a relevant one. Your changes in 
module_finalize() potentially change behaviour. It used to be:

for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	void *seg;
	if (strcmp(".altinstructions", secstrings + s->sh_name))
		continue;
	seg = (void *)s->sh_addr;
	apply_alternatives(seg, seg + s->sh_size);
}

which means that any .altinstructions section would be patched. It's now:

for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	...
	if (!strcmp(".altinstructions", secstrings + s->sh_name))
		alt = s;
	...
}
if (alt) {
	/* patch .altinstructions */
	void *aseg = (void *)alt->sh_addr;
	apply_alternatives(aseg, aseg + alt->sh_size);
}

which means that only the last such section would. I suppose there's 
only one such section anyway, but not seeing a break in the original 
does make me wonder if this was originally done on purpose.

Rene.