Re: [PATCH 3/3] PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Russell King <linux@armlinux.org.uk>,
	kernel-team@android.com
Subject: Re: [PATCH 3/3] PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter()
Date: Fri, 11 Jun 2021 17:49:37 +0100	[thread overview]
Message-ID: <20210611164937.GC9252@lpieralisi> (raw)
In-Reply-To: <20210608172715.2396787-4-maz@kernel.org>

On Tue, Jun 08, 2021 at 06:27:15PM +0100, Marc Zyngier wrote:
> The PSCI CPU suspend code isn't aware of the PMR vs DAIF game,
> resulting in a system that locks up if entering CPU suspend
> with GICv3 pNMI enabled.
> 
> To save the day, teach the suspend code about our new cpuidle
> context helpers, which will do everything that's required just
> like the usual WFI cpuidle code.
> 
> This fixes my Altra system, which would otherwise lock-up at
> boot time when booted with irqchip.gicv3_pseudo_nmi=1.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  drivers/firmware/psci/psci.c | 5 +++++
>  1 file changed, 5 insertions(+)

We need an additional patch for PSCI suspend, regardless:

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 3c1c5daf6df2..d10675bdd9d0 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -333,13 +333,18 @@ static int psci_suspend_finisher(unsigned long state)
>  
>  int psci_cpu_suspend_enter(u32 state)
>  {
> +	struct arm_cpuidle_context context;
>  	int ret;
>  
> +	arm_cpuidle_save_context(&context);
> +
>  	if (!psci_power_state_loses_context(state))
>  		ret = psci_ops.cpu_suspend(state, 0);
>  	else
>  		ret = cpu_suspend(state, psci_suspend_finisher);
>  
> +	arm_cpuidle_restore_context(&context);
> +
>  	return ret;
>  }
>  #endif
> -- 
> 2.30.2
> 

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