On 07/25/2012 04:47 AM, Catalin Marinas wrote: > On Tue, Jul 24, 2012 at 08:42:28PM +0100, Christopher Covington wrote: >> On 01/-10/-28163 02:59 PM, Catalin Marinas wrote: >>> +- Architected timers >>> + CNTFRQ must be programmed with the timer frequency. >>> + If entering the kernel at EL1, CNTHCTL_EL2 must have EL1PCTEN (bit 0) >>> + set where available. >> >> After Marc Zyngier's virtual timer patches come in, will the latter >> requirement only be strictly necessary for kernels wanting to do >> virtualization? > > A kernel is usually entered at EL1 (rather than EL2) if it is a guest. > In this case, the EL1PCTEN bit should have been enabled from the higher > level to give access to the physical counter.
Ah right, those patches still use the physical counter for the clocksource and cyclecounter interfaces. Thanks, Christopher -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/