Subject: [PATCH] ARM/ARM64: arch-timer: fix arch_timer_probed logic

From: [email-masked] (Marc Zyngier)
Date: Mon, 27 Oct 2014 10:33:18 +0000

Hi Daniel,

On 21/10/14 12:12, Daniel Lezcano wrote:
> On 10/21/2014 01:07 PM, Mark Rutland wrote:
>> Hi Daniel,
>>
>> On Tue, Oct 21, 2014 at 11:58:29AM +0100, Daniel Lezcano wrote:
>>> On 10/15/2014 05:06 PM, Marc Zyngier wrote:
>>>> Commit c387f07e6205 (clocksource: arm_arch_timer: Discard unavailable
>>>> timers correctly) changed the way the driver makes sure both the memory
>>>> and system-register timers have been probed before finalizing the probing.
>>>>
>>>> There is a interesting flaw in this logic that leads to this final step
>>>> never to be executed. Things seems to work pretty well until something
>>>> actually needs the data that is produced during this final stage.
>>>>
>>>> For example, KVM explodes on the first run of a guest when executed on
>>>> a platform that has both memory and sysreg nodes (Juno, for example).
>>>>
>>>> Just fix the damned logic, and enjoy booting VMs again.
>>>>
>>>> Tested on a Juno system.
>>>>
>>>> Cc: Sudeep Holla <[email-masked]>
>>>> Cc: Stephen Boyd <[email-masked]>
>>>> Cc: Mark Rutland <[email-masked]>
>>>> Cc: Daniel Lezcano <[email-masked]>
>>>> Cc: Christoffer Dall <[email-masked]>
>>>> Reported-by: Riku Voipio <[email-masked]>
>>>> Signed-off-by: Marc Zyngier <[email-masked]>
>>>> ---
>>>
>>> Applied to my tree. Also for -next.
>>
>> Is this going to hit -rc2? This was a regression introduced in -rc1.
>>
>> Without this fix we've also lost our high precision sched_clock on arm64
>> platforms.
>>
> 
> Sure.
> 
> Thomas or Ingo,
> 
> is it possible to update the tip/urgent branch, so I can send the fixes 
> against 3.18-rc1 ?

Any update on this? -rc2 has landed, but arm/arm64 timers are still in a
rather bad shape. Can this please be merged as an urgent fix?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...