Re: [PATCH] x86,seccomp,prctl: Remove PR_TSC_SIGSEGV and seccomp TSC filtering

[Peter Zijlstra]

On Fri, Oct 03, 2014 at 01:27:52PM -0700, Andy Lutomirski wrote:
> On Fri, Oct 3, 2014 at 1:22 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> >
> > We could make the rule be that RDPMC is enabled if a perf event is
> > mmapped or TIF_SECCOMP is clear, but I'd prefer to be convinced that
> > there's an actual performance issue first.  Ideally we can get this
> > all working with no API or ABI change at all.
> 
> No, we can't use that rule.  But we could say that RDPMC is enabled if
> a perf event is mmapped and no thread in the mm uses seccomp.  I'll
> grumble a little bit about adding yet another piece of seccomp state.

Well, we could simply disable the RDPMC for everything TIF_SECCOMP.
Should be fairly straight fwd.
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