Hi Andre,
On Wed, Feb 19, 2014 at 02:40:27PM +0000, Andre Przywara wrote:
> Hi,
>
> on the Calxeda Midway box a 3.14-rc kernel compiled with KVM support
> crashes during kernel boot:
>
> ...
> [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in
> Hyp mode at: 0x685760
> [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150
> [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0
> [ 3.663897]
> [ 3.663901] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 3.14.0-rc3 #118
> [ 3.663912] CPU1: stopping
> [ 3.663916] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.14.0-rc3 #118
> [ 3.663919] CPU0: stopping
> [ 3.663923] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.14.0-rc3 #118
> [ 3.744453] CPU2: stopping
> [ 3.747151] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc3 #118
>
>
> I traced it down to this commit:
>
> commit 1fcf7ce0c60213994269fb59569ec161eb6e08d6
> Author: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Date: Mon Aug 5 15:04:46 2013 +0100
>
> arm: kvm: implement CPU PM notifier
>
> It seems like there is some address translation confusion if a CPU
> comes out of suspend. I added some debug printks to shed some light on
> the sequence of power management stuff going on.
> The initial per-cpu KVM setup works fine:
> [ 2.402059] switch from the HYP stub to our own HYP init vector
> [ 2.402060] switch from the HYP stub to our own HYP init vector
> [ 2.402062] switch from the HYP stub to our own HYP init vector
> [ 2.402065] __hyp_set_vectors(685760)
> [ 2.402067] __hyp_set_vectors(685760)
> [ 2.402071] __hyp_set_vectors() done
> [ 2.402073] __hyp_set_vectors() done
> [ 2.444884] __hyp_set_vectors(685760)
> [ 2.451486] __hyp_set_vectors() done
> [ 2.456007] switch from the HYP stub to our own HYP init vector
> [ 2.462871] __hyp_set_vectors(685760)
> [ 2.469473] __hyp_set_vectors() done
> [ 2.474035] kvm [1]: interrupt-controller@fff14000 IRQ25
> [ 2.479411] kvm [1]: timer IRQ27
> [ 2.482636] kvm [1]: Hyp mode initialized successfully
>
> Also the new notifier registration goes fine:
> [ 2.487773] calling hyp_cpu_pm_init() (address: c001460c)
> [ 2.494121] calling cpu_pm_register_notifier(c08c3dc8)
> [ 2.502199] cpu_pm_register_notifier(fn=0xc001465c);
> [ 2.507157] cpu_pm_register_notifier() finished
> [ 2.512631] hyp_cpu_pm_init() returned
>
> Then later on (but still without userland) obviously CPU3 goes to sleep
> already (cmd=0) and seems to be woken up again (cmd=2) immediately:
>
> [ 3.643923] hyp_init_cpu_pm_notifier(self=c08c3dc8,cmd=0,v=(null)),CPU: 3
> [ 3.643925] hyp_init_cpu_pm_notifier returns NOTIFY_DONE
> [ 3.643933] psci_cpu_suspend(state.id=0,state.type=1, entry=0x8c44bc);
> [ 3.663884] hyp_init_cpu_pm_notifier(self=c08c3dc8,cmd=2,v=(null)),CPU: 3
> [ 3.663886] calling cpu_init_hyp_mode(NULL) (address=c0014518)
> [ 3.663888] switch from the HYP stub to our own HYP init vector
> [ 3.663890] __hyp_set_vectors(685760)
> [ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in
> Hyp mode at: 0x685760
> [ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150
> [ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0
>
> Obviously it tries to access the physical address. I wonder if there is
> something missing in the Calxeda PSCI firmware?
>
> Has anyone a clue what could go on here?
> Unfortunately it crashes every time at boot if KVM and CONFIG_PM is
> configured - and it worked fine with 3.13.
I think the problem is: the CPU idle driver calls psci_cpu_suspend, that
fails or does not return from reset, so that the CPU state is not lost
on resume but the CPU PM notifier is triggered anyway and that triggers
this issue.
Can you give the following patch a go please ? (whether it is a proper
fix or not it has to be seen).
Thanks,
Lorenzo
-- >8 --
Subject: [PATCH] drivers: cpuidle: calxeda: fix CPU PM notifier usage upon
suspend return
CPU PM notifiers are meant to be triggered when a CPU is reset
after entering a power down procedure so that peripheral CPU state
can be saved and restored. If the power down fails, state is not lost
and cpu_pm_notifier must not be triggered on exit.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
---
drivers/cpuidle/cpuidle-calxeda.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-calxeda.c b/drivers/cpuidle/cpuidle-calxeda.c
index 6e51114..5034f7a 100644
--- a/drivers/cpuidle/cpuidle-calxeda.c
+++ b/drivers/cpuidle/cpuidle-calxeda.c
@@ -41,9 +41,12 @@ static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
+ int ret;
+
cpu_pm_enter();
- cpu_suspend(0, calxeda_idle_finish);
- cpu_pm_exit();
+ ret = cpu_suspend(0, calxeda_idle_finish);
+ if (!ret)
+ cpu_pm_exit();
return index;
}
--
1.8.2.2
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