From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 17 Feb 2011 13:54:57 -0800

Is there a -fdata-align or something? Or would __attribute__((packed))
help? Something that explicitly tells gcc "don't do this", instead of
"let's add indirection and hope gcc doesn't add alignment for _that_".
Especially as the extra pointer makes the code even uglier.

The tracing folks went down the path of trying to use packed in
various ways, to no avail, because no matter what they tried it broke
other things.

And if we do have to use the pointer thing, let's at least then do the
pointer with asms, so that gcc _really_ can't screw it up. Rather than
just move the potential bug around.

That's fine with me.