[PATCH-next] arm: fix clang build warning in include/asm/memory.h

[Yipeng Zou]

在 2024/3/15 8:43, Nathan Chancellor 写道:
> On Thu, Mar 14, 2024 at 03:54:09PM +0800, Yipeng Zou wrote:
>> There is a build error has been founded with build in clang-15.0.4:
>>
>> ./arch/arm/include/asm/memory.h:358:12: error: result of comparison "phys addr_t’ (aka 'unsigned int’) > 4294967295 is always false [-Werror, -Wtautological-type-limit-compare]
>>                               if (addr > (u32)~0)
>>                                   ~~~~ ^ ~~~~~~~
>>
>> It will be always goes fail without CONFIG_PHYS_ADDR_T_64BIT.
>>
>> Directly silence it by Use CONFIG_PHYS_ADDR_T_64BIT.
>>
>> Fixes: 981b6714dbd2 ("ARM: provide improved virt_to_idmap() functionality")
>> Signed-off-by: Yipeng Zou <zouyipeng at huawei.com>
>> ---
>>   arch/arm/include/asm/memory.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
>> index ef2aa79ece5a..64ced9eb42ff 100644
>> --- a/arch/arm/include/asm/memory.h
>> +++ b/arch/arm/include/asm/memory.h
>> @@ -347,14 +347,18 @@ static inline bool arm_has_idmap_alias(void)
>>   	return IS_ENABLED(CONFIG_MMU) && arch_phys_to_idmap_offset != 0;
>>   }
>>   
>> +#ifdef CONFIG_PHYS_ADDR_T_64BIT
>>   #define IDMAP_INVALID_ADDR ((u32)~0)
>> +#endif
>>   
>>   static inline unsigned long phys_to_idmap(phys_addr_t addr)
>>   {
>>   	if (IS_ENABLED(CONFIG_MMU) && arch_phys_to_idmap_offset) {
>>   		addr += arch_phys_to_idmap_offset;
>> +#ifdef CONFIG_PHYS_ADDR_T_64BIT
>>   		if (addr > (u32)~0)
>>   			addr = IDMAP_INVALID_ADDR;
>> +#endif
>>   	}
>>   	return addr;
>>   }
>> -- 
>> 2.34.1
>>
> Would it be better to avoid the ifdef's here and just use IS_ENABLED()?
> I can't see why this would not work for avoiding that warning.
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index ef2aa79ece5a..fbff07bc3b28 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -353,7 +353,7 @@ static inline unsigned long phys_to_idmap(phys_addr_t addr)
>   {
>   	if (IS_ENABLED(CONFIG_MMU) && arch_phys_to_idmap_offset) {
>   		addr += arch_phys_to_idmap_offset;
> -		if (addr > (u32)~0)
> +		if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT) && addr > (u32)~0)
>   			addr = IDMAP_INVALID_ADDR;
>   	}
>   	return addr;

It absolutely works for it and yes, It's a better way to avoiding that.

Will fix it in that way.

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-- 
Regards,
Yipeng Zou