[PATCH v16 06/25] powerpc: mm: Add p?d_leaf() definitions

[PATCH v16 06/25] powerpc: mm: Add p?d_leaf() definitions

[Steven Price]

walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.

For powerpc pmd_large() already exists and does what we want, so hoist
it out of the CONFIG_TRANSPARENT_HUGEPAGE condition and implement the
other levels. Macros are used to provide the generic p?d_leaf() names.

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org
CC: kvm-ppc@vger.kernel.org
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 30 ++++++++++++++------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index b01624e5c467..3dd7b6f5edd0 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -923,6 +923,12 @@ static inline int pud_present(pud_t pud)
 	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
 }
 
+#define pud_leaf	pud_large
+static inline int pud_large(pud_t pud)
+{
+	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
+}
+
 extern struct page *pud_page(pud_t pud);
 extern struct page *pmd_page(pmd_t pmd);
 static inline pte_t pud_pte(pud_t pud)
@@ -966,6 +972,12 @@ static inline int pgd_present(pgd_t pgd)
 	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
 }
 
+#define pgd_leaf	pgd_large
+static inline int pgd_large(pgd_t pgd)
+{
+	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
+}
+
 static inline pte_t pgd_pte(pgd_t pgd)
 {
 	return __pte_raw(pgd_raw(pgd));
@@ -1133,6 +1145,15 @@ static inline bool pmd_access_permitted(pmd_t pmd, bool write)
 	return pte_access_permitted(pmd_pte(pmd), write);
 }
 
+#define pmd_leaf	pmd_large
+/*
+ * returns true for pmd migration entries, THP, devmap, hugetlb
+ */
+static inline int pmd_large(pmd_t pmd)
+{
+	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
+}
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
 extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
@@ -1159,15 +1180,6 @@ pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp,
 	return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
 }
 
-/*
- * returns true for pmd migration entries, THP, devmap, hugetlb
- * But compile time dependent on THP config
- */
-static inline int pmd_large(pmd_t pmd)
-{
-	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
-}
-
 static inline pmd_t pmd_mknotpresent(pmd_t pmd)
 {
 	return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
-- 
2.20.1

Re: [PATCH v16 06/25] powerpc: mm: Add p?d_leaf() definitions

[Michael Ellerman]

Steven Price <steven.price@arm.com> writes:
> walk_page_range() is going to be allowed to walk page tables other than
> those of user space. For this it needs to know when it has reached a
> 'leaf' entry in the page tables. This information is provided by the
> p?d_leaf() functions/macros.
>
> For powerpc pmd_large() already exists and does what we want, so hoist
> it out of the CONFIG_TRANSPARENT_HUGEPAGE condition and implement the
> other levels. Macros are used to provide the generic p?d_leaf() names.
>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Michael Ellerman <mpe@ellerman.id.au>
> CC: linuxppc-dev@lists.ozlabs.org
> CC: kvm-ppc@vger.kernel.org
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/pgtable.h | 30 ++++++++++++++------
>  1 file changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index b01624e5c467..3dd7b6f5edd0 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -923,6 +923,12 @@ static inline int pud_present(pud_t pud)
>  	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
>  }
>  
> +#define pud_leaf	pud_large
> +static inline int pud_large(pud_t pud)
> +{
> +	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
> +}

We already have:

#define pud_is_leaf pud_is_leaf
static inline bool pud_is_leaf(pud_t pud)
{
	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
}

And so on.

These went in relatively recently in:

  d6eacedd1f0e ("powerpc/book3s: Use config independent helpers for page table walk")


Assuming those all work for you, maybe your patch in this series should
just do:

#define pud_leaf pud_is_leaf

And so on. And then we can do a patch later to change the arch/powerpc
code to use pud_leaf() etc. directly and drop the "is" versions.

cheers


> @@ -966,6 +972,12 @@ static inline int pgd_present(pgd_t pgd)
>  	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
>  }
>  
> +#define pgd_leaf	pgd_large
> +static inline int pgd_large(pgd_t pgd)
> +{
> +	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
> +}
> +
>  static inline pte_t pgd_pte(pgd_t pgd)
>  {
>  	return __pte_raw(pgd_raw(pgd));
> @@ -1133,6 +1145,15 @@ static inline bool pmd_access_permitted(pmd_t pmd, bool write)
>  	return pte_access_permitted(pmd_pte(pmd), write);
>  }
>  
> +#define pmd_leaf	pmd_large
> +/*
> + * returns true for pmd migration entries, THP, devmap, hugetlb
> + */
> +static inline int pmd_large(pmd_t pmd)
> +{
> +	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
> +}
> +
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
>  extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
> @@ -1159,15 +1180,6 @@ pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp,
>  	return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
>  }
>  
> -/*
> - * returns true for pmd migration entries, THP, devmap, hugetlb
> - * But compile time dependent on THP config
> - */
> -static inline int pmd_large(pmd_t pmd)
> -{
> -	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
> -}
> -
>  static inline pmd_t pmd_mknotpresent(pmd_t pmd)
>  {
>  	return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
> -- 
> 2.20.1

Re: [PATCH v16 06/25] powerpc: mm: Add p?d_leaf() definitions

[Steven Price]

On 09/12/2019 11:08, Michael Ellerman wrote:
> Steven Price <steven.price@arm.com> writes:
>> walk_page_range() is going to be allowed to walk page tables other than
>> those of user space. For this it needs to know when it has reached a
>> 'leaf' entry in the page tables. This information is provided by the
>> p?d_leaf() functions/macros.
>>
>> For powerpc pmd_large() already exists and does what we want, so hoist
>> it out of the CONFIG_TRANSPARENT_HUGEPAGE condition and implement the
>> other levels. Macros are used to provide the generic p?d_leaf() names.
>>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: Paul Mackerras <paulus@samba.org>
>> CC: Michael Ellerman <mpe@ellerman.id.au>
>> CC: linuxppc-dev@lists.ozlabs.org
>> CC: kvm-ppc@vger.kernel.org
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>>  arch/powerpc/include/asm/book3s/64/pgtable.h | 30 ++++++++++++++------
>>  1 file changed, 21 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index b01624e5c467..3dd7b6f5edd0 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -923,6 +923,12 @@ static inline int pud_present(pud_t pud)
>>  	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
>>  }
>>  
>> +#define pud_leaf	pud_large
>> +static inline int pud_large(pud_t pud)
>> +{
>> +	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>> +}
> 
> We already have:
> 
> #define pud_is_leaf pud_is_leaf
> static inline bool pud_is_leaf(pud_t pud)
> {
> 	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
> }
> 
> And so on.
> 
> These went in relatively recently in:
> 
>   d6eacedd1f0e ("powerpc/book3s: Use config independent helpers for page table walk")
> 
> 
> Assuming those all work for you, maybe your patch in this series should
> just do:
> 
> #define pud_leaf pud_is_leaf
> 
> And so on. And then we can do a patch later to change the arch/powerpc
> code to use pud_leaf() etc. directly and drop the "is" versions.

Thanks for pointing this out - these didn't exist when I started this
patch series, but yes it would be a good idea to make use of them now.
Followed by cleaning up to use the shorter p?d_leaf() versions in a
later patch.

Thanks,

Steve

> cheers
> 
> 
>> @@ -966,6 +972,12 @@ static inline int pgd_present(pgd_t pgd)
>>  	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
>>  }
>>  
>> +#define pgd_leaf	pgd_large
>> +static inline int pgd_large(pgd_t pgd)
>> +{
>> +	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
>> +}
>> +
>>  static inline pte_t pgd_pte(pgd_t pgd)
>>  {
>>  	return __pte_raw(pgd_raw(pgd));
>> @@ -1133,6 +1145,15 @@ static inline bool pmd_access_permitted(pmd_t pmd, bool write)
>>  	return pte_access_permitted(pmd_pte(pmd), write);
>>  }
>>  
>> +#define pmd_leaf	pmd_large
>> +/*
>> + * returns true for pmd migration entries, THP, devmap, hugetlb
>> + */
>> +static inline int pmd_large(pmd_t pmd)
>> +{
>> +	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>> +}
>> +
>>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>  extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
>>  extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
>> @@ -1159,15 +1180,6 @@ pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp,
>>  	return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
>>  }
>>  
>> -/*
>> - * returns true for pmd migration entries, THP, devmap, hugetlb
>> - * But compile time dependent on THP config
>> - */
>> -static inline int pmd_large(pmd_t pmd)
>> -{
>> -	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>> -}
>> -
>>  static inline pmd_t pmd_mknotpresent(pmd_t pmd)
>>  {
>>  	return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
>> -- 
>> 2.20.1
> 
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