Re: [RFC] kern: simple futex for gnumach (version 8)

[Richard Braun]

On Tue, Dec 31, 2013 at 04:26:01PM +0100, Richard Braun wrote:
> On Sun, Dec 29, 2013 at 09:44:51PM +0100, Marin Ramesa wrote:
> > +           simple_lock(&futex->futex_wait_lock);
> > +
> > +           /* If the value is still the same. */
> > +           if (*address == value) {

In addition, such an access should go through some userspace memory
accessor (something like copyin at least, although passing it through
a message would be far cleaner), and it must be atomic. To finish with,
the more I think about it, the less I understand why there is a need
for futex objects in the first place. Instead of dynamically allocating
such structures, it probably makes more sense to use the addresses of
the physical page descriptors instead.

-- 
Richard Braun