On Wed, Nov 27, 2013 at 2:31 PM, H. Peter Anvin <h...@zytor.com> wrote: > No, we're not... sysexit/sysret doesn't count.
So sysexit/sysret doesn't count as a serializing instruction, no. But it doesn't need to, because *self*-modifying code doesn't need a serializing instruction, only a branch. It's only *cross*-modifying code that needs a serializing instruction. So the IPI is sufficient for the cross-modifying case, and the sysret is sufficient for the self-modifying case. And we also don't need to worry about "what happens if we schedule to another CPU, and self-modifying becomes cross-modifying", because the scheduling will then do the serializing instruction. So IPI for other CPU's (limited to the mm-mask) and just a system call for local CPU should be perfectly fine. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/