linux-kernel - Re: [PATCH v6 21/24] arm64: Handle serror in NMI context

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Message-ID: <20181204180917.GE19210@arrakis.emea.arm.com>
Date:   Tue, 4 Dec 2018 18:09:18 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     Julien Thierry <julien.thierry@....com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        daniel.thompson@...aro.org, marc.zyngier@....com,
        will.deacon@....com, linux-kernel@...r.kernel.org,
        christoffer.dall@....com, james.morse@....com,
        joel@...lfernandes.org, Dave Martin <dave.martin@....com>
Subject: Re: [PATCH v6 21/24] arm64: Handle serror in NMI context

On Mon, Nov 12, 2018 at 11:57:12AM +0000, Julien Thierry wrote:
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 5f4d9ac..66344cd 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -897,13 +897,17 @@ bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)
>  
>  asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
>  {
> -	nmi_enter();
> +	const bool was_in_nmi = in_nmi();
> +
> +	if (!was_in_nmi)
> +		nmi_enter();
>  
>  	/* non-RAS errors are not containable */
>  	if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
>  		arm64_serror_panic(regs, esr);
>  
> -	nmi_exit();
> +	if (!was_in_nmi)
> +		nmi_exit();
>  }

Do we actually need nmi_enter/exit in the outer do_serror() function?
Could we just move it to arm64_serror_panic()?

-- 
Catalin