Blackfin: SMP: make all barriers handle cache issues

Blackfin: SMP: make all barriers handle cache issues

When suspending/resuming, the common task freezing code will run in
parallel and freeze processes on each core.  This is because the code
uses the non-smp version of memory barriers (as well it should).

The Blackfin smp barrier logic at the moment contains the cache sync
logic, but the non-smp barriers do not.  This is incorrect as Rafel
summarized:
> ...
> The existing memory barriers are SMP barriers too, but they are more
> than _just_ SMP barriers.  At least that's how it is _supposed_ to be
> (eg. rmb() is supposed to be stronger than smp_rmb()).
> ...
> However, looking at the blackfin's definitions of SMP barriers I see
> that it uses extra stuff that should _also_ be used in the definitions
> of the mandatory barriers.
> ...

URL: http://lkml.org/lkml/2011/4/13/11
LKML-Reference: <BANLkTi=F-C-vwX4PGGfbkdTBw3OWL-twfg@mail.gmail.com>
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>