From mboxrd@z Thu Jan  1 00:00:00 1970
From: daniel.lezcano@linaro.org (Daniel Lezcano)
Date: Tue, 21 Oct 2014 12:58:29 +0200
Subject: [PATCH] ARM/ARM64: arch-timer: fix arch_timer_probed logic
In-Reply-To: <1413385580-23317-1-git-send-email-marc.zyngier@arm.com>
References: <1413385580-23317-1-git-send-email-marc.zyngier@arm.com>
Message-ID: <54463C55.8010209@linaro.org>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

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 <sudeep.holla@arm.com>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Christoffer Dall <christoffer.dall@linaro.org>
> Reported-by: Riku Voipio <riku.voipio@linaro.org>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---

Applied to my tree. Also for -next.

Thanks !

   -- Daniel

>   drivers/clocksource/arm_arch_timer.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 2133f9d..43005d4 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -660,11 +660,11 @@ static bool __init
>   arch_timer_probed(int type, const struct of_device_id *matches)
>   {
>   	struct device_node *dn;
> -	bool probed = false;
> +	bool probed = true;
>
>   	dn = of_find_matching_node(NULL, matches);
> -	if (dn && of_device_is_available(dn) && (arch_timers_present & type))
> -		probed = true;
> +	if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
> +		probed = false;
>   	of_node_put(dn);
>
>   	return probed;
>


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