[PATCH v17 06/23] powerpc: mm: Add p?d_leaf() definitions

[PATCH v17 06/23] 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 p?d_is_leaf() functions already exist. Export them using the
new p?d_leaf() name.

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 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index b01624e5c467..201a69e6a355 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1355,18 +1355,21 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va
  * Like pmd_huge() and pmd_large(), but works regardless of config options
  */
 #define pmd_is_leaf pmd_is_leaf
+#define pmd_leaf pmd_is_leaf
 static inline bool pmd_is_leaf(pmd_t pmd)
 {
 	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
 }
 
 #define pud_is_leaf pud_is_leaf
+#define pud_leaf pud_is_leaf
 static inline bool pud_is_leaf(pud_t pud)
 {
 	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
 }
 
 #define pgd_is_leaf pgd_is_leaf
+#define pgd_leaf pgd_is_leaf
 static inline bool pgd_is_leaf(pgd_t pgd)
 {
 	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
-- 
2.20.1

Re: [PATCH v17 06/23] 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 p?d_is_leaf() functions already exist. Export them using the
> new p?d_leaf() name.
>
> 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 | 3 +++
>  1 file changed, 3 insertions(+)

We have fallback versions of our pmd_is_leaf() etc. in
arch/powerpc/include/asm/pgtable.h, eg:

#ifndef pmd_is_leaf
#define pmd_is_leaf pmd_is_leaf
static inline bool pmd_is_leaf(pmd_t pmd)
{
	return false;
}
#endif

Because we support several different MMUs and most of them don't need to
do anything.

So we could put the compatibility #defines to your names along with the
fallback versions in asm/pgtable.h, rather than in
asm/book3s/64/pgtable.h

But I see you also have fallbacks for your versions, so it probably
doesn't matter either way.

So I'm OK with this version, unless you think there's a compelling
reason to do the compatibility #defines in our asm/pgtable.h

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers


> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index b01624e5c467..201a69e6a355 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -1355,18 +1355,21 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va
>   * Like pmd_huge() and pmd_large(), but works regardless of config options
>   */
>  #define pmd_is_leaf pmd_is_leaf
> +#define pmd_leaf pmd_is_leaf
>  static inline bool pmd_is_leaf(pmd_t pmd)
>  {
>  	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>  }
>  
>  #define pud_is_leaf pud_is_leaf
> +#define pud_leaf pud_is_leaf
>  static inline bool pud_is_leaf(pud_t pud)
>  {
>  	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>  }
>  
>  #define pgd_is_leaf pgd_is_leaf
> +#define pgd_leaf pgd_is_leaf
>  static inline bool pgd_is_leaf(pgd_t pgd)
>  {
>  	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
> -- 
> 2.20.1

Re: [PATCH v17 06/23] powerpc: mm: Add p?d_leaf() definitions

[Steven Price]

On 19/12/2019 11:49, 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 p?d_is_leaf() functions already exist. Export them using the
>> new p?d_leaf() name.
>>
>> 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 | 3 +++
>>  1 file changed, 3 insertions(+)
> 
> We have fallback versions of our pmd_is_leaf() etc. in
> arch/powerpc/include/asm/pgtable.h, eg:
> 
> #ifndef pmd_is_leaf
> #define pmd_is_leaf pmd_is_leaf
> static inline bool pmd_is_leaf(pmd_t pmd)
> {
> 	return false;
> }
> #endif
> 
> Because we support several different MMUs and most of them don't need to
> do anything.
> 
> So we could put the compatibility #defines to your names along with the
> fallback versions in asm/pgtable.h, rather than in
> asm/book3s/64/pgtable.h
> 
> But I see you also have fallbacks for your versions, so it probably
> doesn't matter either way.
> 
> So I'm OK with this version, unless you think there's a compelling
> reason to do the compatibility #defines in our asm/pgtable.h

I was thinking that (assuming this series actually gets merged this
time), the p?d_is_leaf() versions could be removed and replaced by
p?d_leaf() in the future. Since the fallbacks are in the asm-generic
code it makes sense for the pmd_leaf() definitions to be next to the
non-fallback versions.

> Acked-by: Michael Ellerman <mpe@ellerman.id.au>

Thanks!

Steve

> cheers
> 
> 
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index b01624e5c467..201a69e6a355 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -1355,18 +1355,21 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va
>>   * Like pmd_huge() and pmd_large(), but works regardless of config options
>>   */
>>  #define pmd_is_leaf pmd_is_leaf
>> +#define pmd_leaf pmd_is_leaf
>>  static inline bool pmd_is_leaf(pmd_t pmd)
>>  {
>>  	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>>  }
>>  
>>  #define pud_is_leaf pud_is_leaf
>> +#define pud_leaf pud_is_leaf
>>  static inline bool pud_is_leaf(pud_t pud)
>>  {
>>  	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>>  }
>>  
>>  #define pgd_is_leaf pgd_is_leaf
>> +#define pgd_leaf pgd_is_leaf
>>  static inline bool pgd_is_leaf(pgd_t pgd)
>>  {
>>  	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
>> -- 
>> 2.20.1
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>