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SubjectRe: [08/36] AArch64: Kernel booting and initialisation
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.


Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

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