On Thu, 3 Sep 2009 23:18:05 +0200 Ingo Molnar <mingo@xxxxxxx> wrote: > > * H. Peter Anvin <hpa@xxxxxxxxx> wrote: > > > On 09/03/2009 01:45 PM, Jeremy Fitzhardinge wrote: > > > > > > Two problems: > > > > > > * gcc generates %gs: references for stack-protector, but we > > > use %fs for percpu data (because restoring %fs is faster if it's > > > a null selector; TLS uses %gs). I guess we could use %fs if > > > !CONFIG_CC_STACKPROTECTOR, or %gs if we are using it > > > (though that has some fiddly ramifications for things like > > > ptrace). > > > > Well, by touching two segments we're getting the worst of both > > worlds, so at least assuming some significant number of real-world > > deployments use CC_STACKPROTECTOR, we really don't want to > > pessimize that case too much. > > Fedora has stackprotector enabled so it's used in a widespread way. > > Ingo the other issue is that afaik we want the kernel to use the other register than userspace does... -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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