Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
Excerpts from Russell King - ARM Linux admin's message of February 2, 2021 9:13 pm: > On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote: >> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h >> index c02f24400369..d63a5bb6bd0c 100644 >> --- a/arch/arm/include/asm/pgtable.h >> +++ b/arch/arm/include/asm/pgtable.h >> @@ -166,6 +166,9 @@ extern struct page *empty_zero_page; >> >> extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; >> >> +#define pud_page(pud) pmd_page(__pmd(pud_val(pud))) >> +#define pud_write(pud) pmd_write(__pmd(pud_val(pud))) > > As there is no PUD, does it really make sense to return a valid > struct page (which will be the PTE page) for pud_page(), which is > several tables above? There is no PUD on 3-level either, and the pgtable-nopud.h which it uses also passes down p4d_page to pud_page, so by convention... Although in this case at least for my next patch it won't acutally use pud_page unless it's a leaf entry so maybe it shouldn't get called anyway. Thanks, Nick
Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
On Tue, Feb 02, 2021 at 07:47:04PM +0800, Ding Tianhong wrote:
> On 2021/2/2 19:13, Russell King - ARM Linux admin wrote:
> > On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote:
> >> diff --git a/arch/arm/include/asm/pgtable.h
> >> b/arch/arm/include/asm/pgtable.h
> >> index c02f24400369..d63a5bb6bd0c 100644
> >> --- a/arch/arm/include/asm/pgtable.h
> >> +++ b/arch/arm/include/asm/pgtable.h
> >> @@ -166,6 +166,9 @@ extern struct page *empty_zero_page;
> >>
> >> extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
> >>
> >> +#define pud_page(pud) pmd_page(__pmd(pud_val(pud)))
> >> +#define pud_write(pud)pmd_write(__pmd(pud_val(pud)))
> >
> > As there is no PUD, does it really make sense to return a valid
> > struct page (which will be the PTE page) for pud_page(), which is
> > several tables above?
> >
> --- a/arch/arm/include/asm/pgtable-2level.h
> +++ b/arch/arm/include/asm/pgtable-2level.h
>
> +static inline int pud_none(pud_t pud)
> +{
> + return 0;
> +}
>
> I think it could be fix like this.
We already have that.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
On 2021/2/2 19:13, Russell King - ARM Linux admin wrote:
> On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote:
>> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
>> index c02f24400369..d63a5bb6bd0c 100644
>> --- a/arch/arm/include/asm/pgtable.h
>> +++ b/arch/arm/include/asm/pgtable.h
>> @@ -166,6 +166,9 @@ extern struct page *empty_zero_page;
>>
>> extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
>>
>> +#define pud_page(pud) pmd_page(__pmd(pud_val(pud)))
>> +#define pud_write(pud) pmd_write(__pmd(pud_val(pud)))
>
> As there is no PUD, does it really make sense to return a valid
> struct page (which will be the PTE page) for pud_page(), which is
> several tables above?
>
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
+static inline int pud_none(pud_t pud)
+{
+ return 0;
+}
I think it could be fix like this.
Ding
Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
On 2021/2/2 19:47, Ding Tianhong wrote:
> On 2021/2/2 19:13, Russell King - ARM Linux admin wrote:
>> On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote:
>>> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
>>> index c02f24400369..d63a5bb6bd0c 100644
>>> --- a/arch/arm/include/asm/pgtable.h
>>> +++ b/arch/arm/include/asm/pgtable.h
>>> @@ -166,6 +166,9 @@ extern struct page *empty_zero_page;
>>>
>>> extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
>>>
>>> +#define pud_page(pud) pmd_page(__pmd(pud_val(pud)))
>>> +#define pud_write(pud) pmd_write(__pmd(pud_val(pud)))
>>
>> As there is no PUD, does it really make sense to return a valid
>> struct page (which will be the PTE page) for pud_page(), which is
>> several tables above?
>>
> --- a/arch/arm/include/asm/pgtable-2level.h
> +++ b/arch/arm/include/asm/pgtable-2level.h
>
> +static inline int pud_none(pud_t pud)
> +{
> + return 0;
> +}
>
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h>
+static inline int pud_page(pud_t pud)
+{
+ return 0;
+}
> I think it could be fix like this.
>
> Ding
>
Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote: > diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h > index c02f24400369..d63a5bb6bd0c 100644 > --- a/arch/arm/include/asm/pgtable.h > +++ b/arch/arm/include/asm/pgtable.h > @@ -166,6 +166,9 @@ extern struct page *empty_zero_page; > > extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; > > +#define pud_page(pud)pmd_page(__pmd(pud_val(pud))) > +#define pud_write(pud) pmd_write(__pmd(pud_val(pud))) As there is no PUD, does it really make sense to return a valid struct page (which will be the PTE page) for pud_page(), which is several tables above? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
[PATCH v12 01/14] ARM: mm: add missing pud_page define to 2-level page tables
ARM uses its own PMD folding scheme which is missing pud_page which should just pass through to pmd_page. Move this from the 3-level page table to common header. Cc: Russell King Cc: Ding Tianhong Cc: linux-arm-ker...@lists.infradead.org Signed-off-by: Nicholas Piggin --- arch/arm/include/asm/pgtable-3level.h | 2 -- arch/arm/include/asm/pgtable.h| 3 +++ 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 2b85d175e999..d4edab51a77c 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -186,8 +186,6 @@ static inline pte_t pte_mkspecial(pte_t pte) #define pmd_write(pmd) (pmd_isclear((pmd), L_PMD_SECT_RDONLY)) #define pmd_dirty(pmd) (pmd_isset((pmd), L_PMD_SECT_DIRTY)) -#define pud_page(pud) pmd_page(__pmd(pud_val(pud))) -#define pud_write(pud) pmd_write(__pmd(pud_val(pud))) #define pmd_hugewillfault(pmd) (!pmd_young(pmd) || !pmd_write(pmd)) #define pmd_thp_or_huge(pmd) (pmd_huge(pmd) || pmd_trans_huge(pmd)) diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index c02f24400369..d63a5bb6bd0c 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -166,6 +166,9 @@ extern struct page *empty_zero_page; extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; +#define pud_page(pud) pmd_page(__pmd(pud_val(pud))) +#define pud_write(pud) pmd_write(__pmd(pud_val(pud))) + #define pmd_none(pmd) (!pmd_val(pmd)) static inline pte_t *pmd_page_vaddr(pmd_t pmd) -- 2.23.0
