On Tue, Oct 27, 2015 at 07:40:20PM +0100, Peter Zijlstra wrote: > On Tue, Oct 27, 2015 at 04:19:48PM +0000, Will Deacon wrote: > > ... and the 'normal' code will have a control hazard somewhere, followed > > by the implicit ISB in exception return, so there's a barrier of sorts > > there too. > > Which exception return?
The return to userspace after the interrupt/fault/system call that got us into the kernel. > > The problem is that people say "full barrier" without defining what it > > really means, and we end up going round the houses on things like > > transitivity (which ctrl + isb doesn't always give you). > > I pretty much meant smp_mb() here :-) In which case, we don't provide the transitivity guarantees that you would get from an smp_mb(). Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
