Re: [PATCH V2] mm/special: Create generic fallbacks for pte_special() and pte_mkspecial()

[Anshuman Khandual <anshuman.khandual@xxxxxxx>]

On 03/10/2020 06:57 PM, Thomas Bogendoerfer wrote:
> On Tue, Mar 10, 2020 at 06:39:11AM +0530, Anshuman Khandual wrote:
>> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
>> index aef5378f909c..8e4e4be1ca00 100644
>> --- a/arch/mips/include/asm/pgtable.h
>> +++ b/arch/mips/include/asm/pgtable.h
>> @@ -269,6 +269,36 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
>>   */
>>  extern pgd_t swapper_pg_dir[];
>>  
>> +/*
>> + * Platform specific pte_special() and pte_mkspecial() definitions
>> + * are required only when ARCH_HAS_PTE_SPECIAL is enabled.
>> + */
>> +#if !defined(CONFIG_32BIT) && !defined(CONFIG_CPU_HAS_RIXI)
> 
> this looks wrong.
> 
> current Kconfig statement is
> 
> select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
> 
> so we can't use PTE_SPECIAL on 32bit _and_ CPUs with RIXI support.

I already had asked for clarification on this.

> 
> Why can't we use
> 
> #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
> 
> here as the comment already suggests ?

Yes, that will be easier and will automatically adjust in case
ARCH_HAS_PTE_SPECIAL scope changes later. Will respin the patch.

> 
> Thomas.
>