linux-kernel - Re: [PATCH v3 07/17] riscv: misaligned: move emulated access uniformity check in a function

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Message-ID: <20250313-89b46bd06fbea0072ac4932f@orel>
Date: Thu, 13 Mar 2025 14:07:18 +0100
From: Andrew Jones <ajones@...tanamicro.com>
To: Clément Léger <cleger@...osinc.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>, 
	Palmer Dabbelt <palmer@...belt.com>, Anup Patel <anup@...infault.org>, 
	Atish Patra <atishp@...shpatra.org>, Shuah Khan <shuah@...nel.org>, Jonathan Corbet <corbet@....net>, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, 
	kvm@...r.kernel.org, kvm-riscv@...ts.infradead.org, linux-kselftest@...r.kernel.org, 
	Samuel Holland <samuel.holland@...ive.com>
Subject: Re: [PATCH v3 07/17] riscv: misaligned: move emulated access
 uniformity check in a function

On Mon, Mar 10, 2025 at 04:12:14PM +0100, Clément Léger wrote:
> Split the code that check for the uniformity of misaligned accesses
> performance on all cpus from check_unaligned_access_emulated_all_cpus()
> to its own function which will be used for delegation check. No
> functional changes intended.
> 
> Signed-off-by: Clément Léger <cleger@...osinc.com>
> ---
>  arch/riscv/kernel/traps_misaligned.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
> index 7fe25adf2539..db31966a834e 100644
> --- a/arch/riscv/kernel/traps_misaligned.c
> +++ b/arch/riscv/kernel/traps_misaligned.c
> @@ -673,10 +673,20 @@ static int cpu_online_check_unaligned_access_emulated(unsigned int cpu)
>  	return 0;
>  }
>  
> -bool check_unaligned_access_emulated_all_cpus(void)
> +static bool all_cpus_unaligned_scalar_access_emulated(void)
>  {
>  	int cpu;
>  
> +	for_each_online_cpu(cpu)
> +		if (per_cpu(misaligned_access_speed, cpu) !=
> +		    RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED)
> +			return false;
> +
> +	return true;
> +}
> +
> +bool check_unaligned_access_emulated_all_cpus(void)
> +{
>  	/*
>  	 * We can only support PR_UNALIGN controls if all CPUs have misaligned
>  	 * accesses emulated since tasks requesting such control can run on any
> @@ -684,10 +694,8 @@ bool check_unaligned_access_emulated_all_cpus(void)
>  	 */
>  	on_each_cpu(check_unaligned_access_emulated, NULL, 1);
>  
> -	for_each_online_cpu(cpu)
> -		if (per_cpu(misaligned_access_speed, cpu)
> -		    != RISCV_HWPROBE_MISALIGNED_SCALAR_EMULATED)
> -			return false;
> +	if (!all_cpus_unaligned_scalar_access_emulated())
> +		return false;
>  
>  	unaligned_ctl = true;
>  	return true;
> -- 
> 2.47.2
>

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>