Date: Wed, 18 Oct 2000 14:32:00 -0700 From: Mike Smith <msmith@freebsd.org> To: mjacob@feral.com Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/include bus_at386.h bus_pc98.h src/sys/ia64/include bus.h src/sys/alpha/include bus.h Message-ID: <200010182132.e9ILW0h00958@mass.osd.bsdi.com> In-Reply-To: Your message of "Wed, 18 Oct 2000 08:40:05 PDT." <Pine.GSO.4.21.0010180839330.19429-100000@bird.feral.com>
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>
> From the point of view of multiple platform architectures, are the semantics
> of these guaranteed to include synchronization wrt I/O devices?
These are semantically equivalent to the bus_space_barrier() operations
applied to a bus space that represents system memory.
ie. no, they don't. You should use bus_space_barrier() against the bus
space(s) your peripheral occupies. (Yeah, this is a bit of overkill...)
>
> On Wed, 18 Oct 2000, John Baldwin wrote:
>
> > jhb 2000/10/18 03:30:12 PDT
> >
> > Modified files:
> > sys/i386/include bus_at386.h bus_pc98.h
> > sys/ia64/include bus.h
> > sys/alpha/include bus.h
> > Log:
> > Add in a simple API for memory barriers to machine/bus.h:
> > - barrier_read() enforces a memory read barrier
> > - barrier_write() enforces a memory write barrier
> > - barrier_rw() enforces a memory read/write barrier
> >
> > Revision Changes Path
> > 1.11 +24 -1 src/sys/i386/include/bus_at386.h
> > 1.12 +24 -1 src/sys/i386/include/bus_pc98.h
> > 1.2 +23 -1 src/sys/ia64/include/bus.h
> > 1.7 +13 -1 src/sys/alpha/include/bus.h
> >
> >
>
>
>
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
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