Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods

H. Peter Anvin
2009-06-15T20:47:59Z

Linus Torvalds wrote:
>
> On Mon, 15 Jun 2009, Jeremy Fitzhardinge wrote:
>> We have to restore the usermode %gs somewhere...
>
> None of this is useful for user-mode return _anyway_, since you have to
> restore %cs/%ss too. At that point, you have to use iret.
>

cs/ss you could potentially restore with sysret/sysexit, at least for
the common case. Of course, this means more cases...

-hpa