On Thu, May 08, 2014 at 12:49:04AM +0100, Kevin Hilman wrote: > Hi Will,
Hello Kevin, > Will Deacon <[email protected]> writes: > > On Wed, May 07, 2014 at 12:32:29AM +0100, Larry Bassel wrote: > >> Make calls to ct_user_enter when the kernel is exited > >> and ct_user_exit when the kernel is entered (in el0_da, > >> el0_ia, el0_svc, el0_irq). > > > > Why only these entry points? I can reschedule after any exception from EL0, > > so I'd expect all exceptions from userspace to need annotating, no? > > In my initial approach to this, you might recall (though it was over a > year ago now) was to just instrument kernel_enter rather than sprinkle > the instrumentaion in cl0_*. However, your concern at the time was that > since it was before debugging was enabled it would complicate debugging > these paths. > > Any chance you have any other suggestion on how we might do this in > kernel_entry rather than sprinkling them all over cl0_*? or is the > sprinkling the only good way to handle this. Unfortunately, different exceptions do subtly different things before invoking the main handler. For example: - Stashing the far - Enabling IRQs - Enabling debug - All the stuff on the syscall path so putting the logic in kernel_entry isn't really do-able, unfortunately. Will -- 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/
