Re: [PATCH v2 3/6] mm/powerpc/8xx: constify ptep_get() argument

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Hi Lorenzo,

Le 04/08/2026 à 13:13, Lorenzo Stoakes (ARM) a écrit :
> On Mon, Aug 03, 2026 at 05:43:57PM +0100, Pedro Falcato wrote:
>> There is no need for write access to the PTE.
>>
>> Signed-off-by: Pedro Falcato <pfalcato@suse.de>
> 
> With below addressed LGTM so:
> 
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> 
>> ---
>>   arch/powerpc/include/asm/nohash/32/pte-8xx.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> index e2ea8ba9f8ca..f2bab31040c7 100644
>> --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
>> @@ -226,7 +226,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
>>
>>   #ifdef CONFIG_PPC_16K_PAGES
>>   #define ptep_get ptep_get
>> -static inline pte_t ptep_get(pte_t *ptep)
>> +static inline pte_t ptep_get(const pte_t *ptep)
>>   {
>>   	pte_basic_t val = READ_ONCE(ptep->pte);
>>   	pte_t pte = {val, val, val, val};
> 
> Worth making these const too (that {val, val, val, val} horrifies me btw :)?

Any suggestion welcome.

powerpc 8xx page table is independant on page size. When you use 16k 
pages, depending on the address you hit the page for the first time, the 
HW assist page table walk will fetch one of four 4k cells in page table 
that need to be identical as they all four define the same 16k page. Not 
sure I'm clear.

Christophe