Messages in this thread | | | Date | Mon, 15 Jun 2009 13:42:32 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods |
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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
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