Re: [PATCH v6 05/18] arm64: create macro to park cpu in an infinite loop

From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Amit Daniel Kachhap <amit.kachhap@arm.com>,
	linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Kristina Martsenko <kristina.martsenko@arm.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Mark Brown <broonie@kernel.org>,
	James Morse <james.morse@arm.com>,
	Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH v6 05/18] arm64: create macro to park cpu in an infinite loop
Date: Tue, 10 Mar 2020 12:02:18 +0000	[thread overview]
Message-ID: <45fcfb45-3c29-cff5-d725-232daa967ee8@arm.com> (raw)
In-Reply-To: <1583476525-13505-6-git-send-email-amit.kachhap@arm.com>

On 3/6/20 6:35 AM, Amit Daniel Kachhap wrote:
> A macro early_park_cpu is added to park the faulted cpu in an infinite
> loop. Currently, this macro is substituted in two instances and may be
> reused in future.
> 

Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>

> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
> ---
>  arch/arm64/kernel/head.S | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 989b194..3d18163 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -761,6 +761,17 @@ ENDPROC(__secondary_too_slow)
>  	.endm
>  
>  /*
> + * Macro to park the cpu in an infinite loop.
> + */
> +	.macro	early_park_cpu status
> +	update_early_cpu_boot_status \status | CPU_STUCK_IN_KERNEL, x1, x2
> +.Lepc_\@:
> +	wfe
> +	wfi
> +	b	.Lepc_\@
> +	.endm
> +
> +/*
>   * Enable the MMU.
>   *
>   *  x0  = SCTLR_EL1 value for turning on the MMU.
> @@ -808,24 +819,14 @@ ENTRY(__cpu_secondary_check52bitva)
>  	and	x0, x0, #(0xf << ID_AA64MMFR2_LVA_SHIFT)
>  	cbnz	x0, 2f
>  
> -	update_early_cpu_boot_status \
> -		CPU_STUCK_IN_KERNEL | CPU_STUCK_REASON_52_BIT_VA, x0, x1
> -1:	wfe
> -	wfi
> -	b	1b
> -
> +	early_park_cpu CPU_STUCK_REASON_52_BIT_VA
>  #endif
>  2:	ret
>  ENDPROC(__cpu_secondary_check52bitva)
>  
>  __no_granule_support:
>  	/* Indicate that this CPU can't boot and is stuck in the kernel */
> -	update_early_cpu_boot_status \
> -		CPU_STUCK_IN_KERNEL | CPU_STUCK_REASON_NO_GRAN, x1, x2
> -1:
> -	wfe
> -	wfi
> -	b	1b
> +	early_park_cpu CPU_STUCK_REASON_NO_GRAN
>  ENDPROC(__no_granule_support)
>  
>  #ifdef CONFIG_RELOCATABLE
> 

-- 
Regards,
Vincenzo

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