[PATCH] arm64: cpufeature: Use defined macro instead of magic numbers

[PATCH] arm64: cpufeature: Use defined macro instead of magic numbers

[Shaokun Zhang]

Macro 'CLIDR_LOUU_SHIFT' and 'CLIDR_LOUIS_SHIFT' are defined, so use
these to replace the magic numbers.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
---
 arch/arm64/kernel/cpufeature.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 125d5c9471ac..4ee3496bcff8 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1733,7 +1733,7 @@ static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
 	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
 
 	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
-	WARN_ON(val & (7 << 27 | 7 << 21));
+	WARN_ON(val & (7 << CLIDR_LOUU_SHIFT | 7 << CLIDR_LOUIS_SHIFT));
 }
 
 #ifdef CONFIG_ARM64_PAN
-- 
2.7.4


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Re: [PATCH] arm64: cpufeature: Use defined macro instead of magic numbers

[Will Deacon]

On Wed, Jul 14, 2021 at 02:13:03PM +0800, Shaokun Zhang wrote:
> Macro 'CLIDR_LOUU_SHIFT' and 'CLIDR_LOUIS_SHIFT' are defined, so use
> these to replace the magic numbers.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
> ---
>  arch/arm64/kernel/cpufeature.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 125d5c9471ac..4ee3496bcff8 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1733,7 +1733,7 @@ static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
>  	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
>  
>  	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
> -	WARN_ON(val & (7 << 27 | 7 << 21));
> +	WARN_ON(val & (7 << CLIDR_LOUU_SHIFT | 7 << CLIDR_LOUIS_SHIFT));
>  }

I think this would be even better as:

	WARN_ON(CLIDR_LOUU(val) || CLIDR_LOUIS(val));

Will

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Re: [PATCH] arm64: cpufeature: Use defined macro instead of magic numbers

[Shaokun Zhang]

Hi Will,

On 2021/7/16 0:31, Will Deacon wrote:
> On Wed, Jul 14, 2021 at 02:13:03PM +0800, Shaokun Zhang wrote:
>> Macro 'CLIDR_LOUU_SHIFT' and 'CLIDR_LOUIS_SHIFT' are defined, so use
>> these to replace the magic numbers.
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Marc Zyngier <maz@kernel.org>
>> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
>> ---
>>  arch/arm64/kernel/cpufeature.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index 125d5c9471ac..4ee3496bcff8 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -1733,7 +1733,7 @@ static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
>>  	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
>>  
>>  	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
>> -	WARN_ON(val & (7 << 27 | 7 << 21));
>> +	WARN_ON(val & (7 << CLIDR_LOUU_SHIFT | 7 << CLIDR_LOUIS_SHIFT));
>>  }
> 
> I think this would be even better as:
> 
> 	WARN_ON(CLIDR_LOUU(val) || CLIDR_LOUIS(val));

Good catch, will follow it in next version.

Thanks,
Shaokun

> 
> Will
> .
> 

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