[PATCH] powerpc/mm: Add _PAGE_SAO to _PAGE_CACHE_CTL mask

[Alexey Kardashevskiy]

On 29/01/2019 04:31, Reza Arbab wrote:
> In htab_convert_pte_flags(), _PAGE_CACHE_CTL is used to check for the
> _PAGE_SAO flag:
> 
>   else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO)
>           rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M);
> 
> But, it isn't defined to include that flag:
> 
>   #define _PAGE_CACHE_CTL (_PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
> 
> This happens to work, but only because of the flag values:
> 
>   #define _PAGE_SAO               0x00010 /* Strong access order */
>   #define _PAGE_NON_IDEMPOTENT    0x00020 /* non idempotent memory */
>   #define _PAGE_TOLERANT          0x00030 /* tolerant memory, cache inhibited */
> 
> To prevent any issues if these particulars ever change, add _PAGE_SAO to
> the mask.


This does not feel right, doing

#define _PAGE_CACHE_CTL	0x30

would make more sense as SAO/NI/TOLERANT is enum so applying "|" to them
just seems wrong.


> 
> Suggested-by: Charles Johns <crjohns at us.ibm.com>
> Signed-off-by: Reza Arbab <arbab at linux.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 2e6ada2..1d97a28 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -811,7 +811,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
>  	return hash__set_pte_at(mm, addr, ptep, pte, percpu);
>  }
>  
> -#define _PAGE_CACHE_CTL	(_PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
> +#define _PAGE_CACHE_CTL	(_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
>  
>  #define pgprot_noncached pgprot_noncached
>  static inline pgprot_t pgprot_noncached(pgprot_t prot)
> 

-- 
Alexey