On Thu, Jun 19, 2014 at 10:31:29PM +0200, Stephane Eranian wrote: > On Thu, Jun 19, 2014 at 10:18 PM, Andi Kleen <[email protected]> wrote: > >> I don't quite understand that. > >> You need to know which events support PEBS. You need a table > > > > We're talking about the kernel allowing things here. > > Yes the user still needs to know what supports PEBS, but > > that doesn't concern the kernel. > > > Just need to make sure you don't return bogus information.
GIGO. We only need to prevent security issues. > > You can just allow it for all, it's a nop if the event doesn't > > support it. And also the fields like DataLA are simply 0 when > > not supported. > > > > Let's take a example. If I do resource_stalls:pp, the kernel > will let it go through and clear the PMI bit on the config as > is required for PEBS mode. The counter will count normally > and never fire an interrupt, even when it overflows. It would > never execute the PMI handler and thus never look at the > PEBS content. You'd never get any samples. Yes if the user specifies a bogus raw event it will not count. That's fine. The important part is just that nothing ever crashes. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
