On 4/21/22 13:50, Tong Tiangen wrote:
> Move ptep_clear() to the include/linux/pgtable.h and add page table check
> relate hooks to some helpers, it's prepare for support page table check
> feature on new architecture.
Could instrumenting generic page table helpers (fallback instances when its
corresponding __HAVE_ARCH_XXX is not defined on the platform), might add all
the page table check hooks into paths on platforms which have not subscribed
ARCH_SUPPORTS_PAGE_TABLE_CHECK in the first place ? Although these looks have
!CONFIG_PAGE_TABLE_CHECK fallback stubs in the header, hence a build problem
gets avoided.
>
> Signed-off-by: Tong Tiangen <[email protected]>
> Acked-by: Pasha Tatashin <[email protected]>
> ---
> arch/x86/include/asm/pgtable.h | 10 ----------
> include/linux/pgtable.h | 26 ++++++++++++++++++--------
> 2 files changed, 18 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 564abe42b0f7..51cd39858f81 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1073,16 +1073,6 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
> return pte;
> }
>
> -#define __HAVE_ARCH_PTEP_CLEAR
AFICS X86 is the only platform subscribing __HAVE_ARCH_PTEP_CLEAR. Hence if
this is getting dropped for generic ptep_clear(), then no need to add back
#ifnded __HAVE_ARCH_PTEP_CLEAR construct. Generic ptep_clear() is the only
definition for all platforms ?
Also if this patch is trying to drop off __HAVE_ARCH_PTEP_CLEAR along with
other page table check related changes, it needs to be done via a separate
patch instead.
> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
> - pte_t *ptep)
> -{
> - if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
> - ptep_get_and_clear(mm, addr, ptep);
> - else
> - pte_clear(mm, addr, ptep);
> -}
> -
> #define __HAVE_ARCH_PTEP_SET_WRPROTECT
> static inline void ptep_set_wrprotect(struct mm_struct *mm,
> unsigned long addr, pte_t *ptep)
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 49ab8ee2d6d7..10d2d91edf20 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -12,6 +12,7 @@
> #include <linux/bug.h>
> #include <linux/errno.h>
> #include <asm-generic/pgtable_uffd.h>
> +#include <linux/page_table_check.h>
>
> #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
> defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
> @@ -272,14 +273,6 @@ static inline bool arch_has_hw_pte_young(void)
> }
> #endif
>
> -#ifndef __HAVE_ARCH_PTEP_CLEAR
> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
> - pte_t *ptep)
> -{
> - pte_clear(mm, addr, ptep);
> -}
> -#endif
> -
> #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
> static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> unsigned long address,
> @@ -287,10 +280,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> {
> pte_t pte = *ptep;
> pte_clear(mm, address, ptep);
> + page_table_check_pte_clear(mm, address, pte);
> return pte;
> }
> #endif
>
> +#ifndef __HAVE_ARCH_PTEP_CLEAR
> +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
> + pte_t *ptep)
> +{
> + if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
> + ptep_get_and_clear(mm, addr, ptep);
> + else
> + pte_clear(mm, addr, ptep);
Could not this be reworked to avoid IS_ENABLED() ? This is confusing. If the page
table hooks can be added to all potential page table paths via generic helpers,
irrespective of CONFIG_PAGE_TABLE_CHECK option, there is no rationale for doing
a IS_ENABLED() check here.
> +}
> +#endif
> +
> #ifndef __HAVE_ARCH_PTEP_GET
> static inline pte_t ptep_get(pte_t *ptep)
> {
> @@ -360,7 +365,10 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
> pmd_t *pmdp)
> {
> pmd_t pmd = *pmdp;
> +
> pmd_clear(pmdp);
> + page_table_check_pmd_clear(mm, address, pmd);
> +
> return pmd;
> }
> #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
> @@ -372,6 +380,8 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
> pud_t pud = *pudp;
>
> pud_clear(pudp);
> + page_table_check_pud_clear(mm, address, pud);
> +
> return pud;
> }
> #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
在 2022/4/22 14:05, Anshuman Khandual 写道:
>
>
> On 4/21/22 13:50, Tong Tiangen wrote:
>> Move ptep_clear() to the include/linux/pgtable.h and add page table check
>> relate hooks to some helpers, it's prepare for support page table check
>> feature on new architecture.
>
> Could instrumenting generic page table helpers (fallback instances when its
> corresponding __HAVE_ARCH_XXX is not defined on the platform), might add all
> the page table check hooks into paths on platforms which have not subscribed
> ARCH_SUPPORTS_PAGE_TABLE_CHECK in the first place ? Although these looks have
> !CONFIG_PAGE_TABLE_CHECK fallback stubs in the header, hence a build problem
> gets avoided.
Right, build problems are avoided by fallback stubs in the header file.
>
>>
>> Signed-off-by: Tong Tiangen <[email protected]>
>> Acked-by: Pasha Tatashin <[email protected]>
>> ---
>> arch/x86/include/asm/pgtable.h | 10 ----------
>> include/linux/pgtable.h | 26 ++++++++++++++++++--------
>> 2 files changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
>> index 564abe42b0f7..51cd39858f81 100644
>> --- a/arch/x86/include/asm/pgtable.h
>> +++ b/arch/x86/include/asm/pgtable.h
>> @@ -1073,16 +1073,6 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
>> return pte;
>> }
>>
>> -#define __HAVE_ARCH_PTEP_CLEAR
>
> AFICS X86 is the only platform subscribing __HAVE_ARCH_PTEP_CLEAR. Hence if
> this is getting dropped for generic ptep_clear(), then no need to add back
> #ifnded __HAVE_ARCH_PTEP_CLEAR construct. Generic ptep_clear() is the only
> definition for all platforms ?
>
> Also if this patch is trying to drop off __HAVE_ARCH_PTEP_CLEAR along with
> other page table check related changes, it needs to be done via a separate
> patch instead.
Agreed.
IMO, this fix can be patched later.
>
>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>> - pte_t *ptep)
>> -{
>> - if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>> - ptep_get_and_clear(mm, addr, ptep);
>> - else
>> - pte_clear(mm, addr, ptep);
>> -}
>> -
>> #define __HAVE_ARCH_PTEP_SET_WRPROTECT
>> static inline void ptep_set_wrprotect(struct mm_struct *mm,
>> unsigned long addr, pte_t *ptep)
>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>> index 49ab8ee2d6d7..10d2d91edf20 100644
>> --- a/include/linux/pgtable.h
>> +++ b/include/linux/pgtable.h
>> @@ -12,6 +12,7 @@
>> #include <linux/bug.h>
>> #include <linux/errno.h>
>> #include <asm-generic/pgtable_uffd.h>
>> +#include <linux/page_table_check.h>
>>
>> #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
>> defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
>> @@ -272,14 +273,6 @@ static inline bool arch_has_hw_pte_young(void)
>> }
>> #endif
>>
>> -#ifndef __HAVE_ARCH_PTEP_CLEAR
>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>> - pte_t *ptep)
>> -{
>> - pte_clear(mm, addr, ptep);
>> -}
>> -#endif
>> -
>> #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
>> static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>> unsigned long address,
>> @@ -287,10 +280,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>> {
>> pte_t pte = *ptep;
>> pte_clear(mm, address, ptep);
>> + page_table_check_pte_clear(mm, address, pte);
>> return pte;
>> }
>> #endif
>>
>> +#ifndef __HAVE_ARCH_PTEP_CLEAR
>> +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>> + pte_t *ptep)
>> +{
>> + if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>> + ptep_get_and_clear(mm, addr, ptep);
>> + else
>> + pte_clear(mm, addr, ptep);
>
> Could not this be reworked to avoid IS_ENABLED() ? This is confusing. If the page
> table hooks can be added to all potential page table paths via generic helpers,
> irrespective of CONFIG_PAGE_TABLE_CHECK option, there is no rationale for doing
> a IS_ENABLED() check here.
>
From the perspective of code logic, we need to check the pte before
being cleared. Whether pte check is required depends on IS_ENABLED().
Are there any suggestions for better implementation?
Thank you,
Tong.
>> +}
>> +#endif
>> +
>> #ifndef __HAVE_ARCH_PTEP_GET
>> static inline pte_t ptep_get(pte_t *ptep)
>> {
>> @@ -360,7 +365,10 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>> pmd_t *pmdp)
>> {
>> pmd_t pmd = *pmdp;
>> +
>> pmd_clear(pmdp);
>> + page_table_check_pmd_clear(mm, address, pmd);
>> +
>> return pmd;
>> }
>> #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
>> @@ -372,6 +380,8 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
>> pud_t pud = *pudp;
>>
>> pud_clear(pudp);
>> + page_table_check_pud_clear(mm, address, pud);
>> +
>> return pud;
>> }
>> #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
> .
On 4/24/22 09:40, Tong Tiangen wrote:
>
>
> 在 2022/4/22 14:05, Anshuman Khandual 写道:
>>
>>
>> On 4/21/22 13:50, Tong Tiangen wrote:
>>> Move ptep_clear() to the include/linux/pgtable.h and add page table check
>>> relate hooks to some helpers, it's prepare for support page table check
>>> feature on new architecture.
>>
>> Could instrumenting generic page table helpers (fallback instances when its
>> corresponding __HAVE_ARCH_XXX is not defined on the platform), might add all
>> the page table check hooks into paths on platforms which have not subscribed
>> ARCH_SUPPORTS_PAGE_TABLE_CHECK in the first place ? Although these looks have
>> !CONFIG_PAGE_TABLE_CHECK fallback stubs in the header, hence a build problem
>> gets avoided.
>
> Right, build problems are avoided by fallback stubs in the header file.
Although there might not be a build problem as such, but should non subscribing
platforms get their page table helpers instrumented with page table check hooks
in the first place ? The commit message should address these questions.
>
>>
>>>
>>> Signed-off-by: Tong Tiangen <[email protected]>
>>> Acked-by: Pasha Tatashin <[email protected]>
>>> ---
>>> arch/x86/include/asm/pgtable.h | 10 ----------
>>> include/linux/pgtable.h | 26 ++++++++++++++++++--------
>>> 2 files changed, 18 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
>>> index 564abe42b0f7..51cd39858f81 100644
>>> --- a/arch/x86/include/asm/pgtable.h
>>> +++ b/arch/x86/include/asm/pgtable.h
>>> @@ -1073,16 +1073,6 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
>>> return pte;
>>> }
>>> -#define __HAVE_ARCH_PTEP_CLEAR
>>
>> AFICS X86 is the only platform subscribing __HAVE_ARCH_PTEP_CLEAR. Hence if
>> this is getting dropped for generic ptep_clear(), then no need to add back
>> #ifnded __HAVE_ARCH_PTEP_CLEAR construct. Generic ptep_clear() is the only
>> definition for all platforms ?
>>
>> Also if this patch is trying to drop off __HAVE_ARCH_PTEP_CLEAR along with
>> other page table check related changes, it needs to be done via a separate
>> patch instead.
>
> Agreed.
> IMO, this fix can be patched later.
>
>>
>>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>> - pte_t *ptep)
>>> -{
>>> - if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>>> - ptep_get_and_clear(mm, addr, ptep);
>>> - else
>>> - pte_clear(mm, addr, ptep);
>>> -}
>>> -
>>> #define __HAVE_ARCH_PTEP_SET_WRPROTECT
>>> static inline void ptep_set_wrprotect(struct mm_struct *mm,
>>> unsigned long addr, pte_t *ptep)
>>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>>> index 49ab8ee2d6d7..10d2d91edf20 100644
>>> --- a/include/linux/pgtable.h
>>> +++ b/include/linux/pgtable.h
>>> @@ -12,6 +12,7 @@
>>> #include <linux/bug.h>
>>> #include <linux/errno.h>
>>> #include <asm-generic/pgtable_uffd.h>
>>> +#include <linux/page_table_check.h>
>>> #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
>>> defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
>>> @@ -272,14 +273,6 @@ static inline bool arch_has_hw_pte_young(void)
>>> }
>>> #endif
>>> -#ifndef __HAVE_ARCH_PTEP_CLEAR
>>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>> - pte_t *ptep)
>>> -{
>>> - pte_clear(mm, addr, ptep);
>>> -}
>>> -#endif
>>> -
>>> #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
>>> static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>>> unsigned long address,
>>> @@ -287,10 +280,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>>> {
>>> pte_t pte = *ptep;
>>> pte_clear(mm, address, ptep);
>>> + page_table_check_pte_clear(mm, address, pte);
>>> return pte;
>>> }
>>> #endif
>>> +#ifndef __HAVE_ARCH_PTEP_CLEAR
>>> +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>> + pte_t *ptep)
>>> +{
>>> + if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>>> + ptep_get_and_clear(mm, addr, ptep);
>>> + else
>>> + pte_clear(mm, addr, ptep);
>>
>> Could not this be reworked to avoid IS_ENABLED() ? This is confusing. If the page
>> table hooks can be added to all potential page table paths via generic helpers,
>> irrespective of CONFIG_PAGE_TABLE_CHECK option, there is no rationale for doing
>> a IS_ENABLED() check here.
>>
>
> From the perspective of code logic, we need to check the pte before being cleared. Whether pte check is required depends on IS_ENABLED().
>
> Are there any suggestions for better implementation?
But other generic page table helpers already have page table check hooks
instrumented without IS_ENABLED() checks, then why this is any different.
>
> Thank you,
> Tong.
>
>>> +}
>>> +#endif
>>> +
>>> #ifndef __HAVE_ARCH_PTEP_GET
>>> static inline pte_t ptep_get(pte_t *ptep)
>>> {
>>> @@ -360,7 +365,10 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>>> pmd_t *pmdp)
>>> {
>>> pmd_t pmd = *pmdp;
>>> +
>>> pmd_clear(pmdp);
>>> + page_table_check_pmd_clear(mm, address, pmd);
>>> +
>>> return pmd;
>>> }
>>> #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
>>> @@ -372,6 +380,8 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
>>> pud_t pud = *pudp;
>>> pud_clear(pudp);
>>> + page_table_check_pud_clear(mm, address, pud);
>>> +
>>> return pud;
>>> }
>>> #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
>> .
在 2022/4/25 13:52, Anshuman Khandual 写道:
>
>
> On 4/24/22 09:40, Tong Tiangen wrote:
>>
>>
>> 在 2022/4/22 14:05, Anshuman Khandual 写道:
>>>
>>>
>>> On 4/21/22 13:50, Tong Tiangen wrote:
>>>> Move ptep_clear() to the include/linux/pgtable.h and add page table check
>>>> relate hooks to some helpers, it's prepare for support page table check
>>>> feature on new architecture.
>>>
>>> Could instrumenting generic page table helpers (fallback instances when its
>>> corresponding __HAVE_ARCH_XXX is not defined on the platform), might add all
>>> the page table check hooks into paths on platforms which have not subscribed
>>> ARCH_SUPPORTS_PAGE_TABLE_CHECK in the first place ? Although these looks have
>>> !CONFIG_PAGE_TABLE_CHECK fallback stubs in the header, hence a build problem
>>> gets avoided.
>>
>> Right, build problems are avoided by fallback stubs in the header file.
>
> Although there might not be a build problem as such, but should non subscribing
> platforms get their page table helpers instrumented with page table check hooks
> in the first place ? The commit message should address these questions.
>
Add description in commit message to explain that:
Non subscription platforms will call a fallback ptc stubs when getting
their page table helpers[1] in include/linux/pgtable.h.
[1]
ptep_clear/ptep_get_and_clear/pmdp_huge_get_and_clear/pudp_huge_get_and_clear
Am i right? :)
Thanks,
Tong.
>>
>>>
>>>>
>>>> Signed-off-by: Tong Tiangen <[email protected]>
>>>> Acked-by: Pasha Tatashin <[email protected]>
>>>> ---
>>>> arch/x86/include/asm/pgtable.h | 10 ----------
>>>> include/linux/pgtable.h | 26 ++++++++++++++++++--------
>>>> 2 files changed, 18 insertions(+), 18 deletions(-)
>>>>
>>>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
>>>> index 564abe42b0f7..51cd39858f81 100644
>>>> --- a/arch/x86/include/asm/pgtable.h
>>>> +++ b/arch/x86/include/asm/pgtable.h
>>>> @@ -1073,16 +1073,6 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
>>>> return pte;
>>>> }
>>>> -#define __HAVE_ARCH_PTEP_CLEAR
>>>
>>> AFICS X86 is the only platform subscribing __HAVE_ARCH_PTEP_CLEAR. Hence if
>>> this is getting dropped for generic ptep_clear(), then no need to add back
>>> #ifnded __HAVE_ARCH_PTEP_CLEAR construct. Generic ptep_clear() is the only
>>> definition for all platforms ?
>>>
>>> Also if this patch is trying to drop off __HAVE_ARCH_PTEP_CLEAR along with
>>> other page table check related changes, it needs to be done via a separate
>>> patch instead.
>>
>> Agreed.
>> IMO, this fix can be patched later.
>>
>>>
>>>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>>> - pte_t *ptep)
>>>> -{
>>>> - if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>>>> - ptep_get_and_clear(mm, addr, ptep);
>>>> - else
>>>> - pte_clear(mm, addr, ptep);
>>>> -}
>>>> -
>>>> #define __HAVE_ARCH_PTEP_SET_WRPROTECT
>>>> static inline void ptep_set_wrprotect(struct mm_struct *mm,
>>>> unsigned long addr, pte_t *ptep)
>>>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>>>> index 49ab8ee2d6d7..10d2d91edf20 100644
>>>> --- a/include/linux/pgtable.h
>>>> +++ b/include/linux/pgtable.h
>>>> @@ -12,6 +12,7 @@
>>>> #include <linux/bug.h>
>>>> #include <linux/errno.h>
>>>> #include <asm-generic/pgtable_uffd.h>
>>>> +#include <linux/page_table_check.h>
>>>> #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
>>>> defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
>>>> @@ -272,14 +273,6 @@ static inline bool arch_has_hw_pte_young(void)
>>>> }
>>>> #endif
>>>> -#ifndef __HAVE_ARCH_PTEP_CLEAR
>>>> -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>>> - pte_t *ptep)
>>>> -{
>>>> - pte_clear(mm, addr, ptep);
>>>> -}
>>>> -#endif
>>>> -
>>>> #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
>>>> static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>>>> unsigned long address,
>>>> @@ -287,10 +280,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
>>>> {
>>>> pte_t pte = *ptep;
>>>> pte_clear(mm, address, ptep);
>>>> + page_table_check_pte_clear(mm, address, pte);
>>>> return pte;
>>>> }
>>>> #endif
>>>> +#ifndef __HAVE_ARCH_PTEP_CLEAR
>>>> +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
>>>> + pte_t *ptep)
>>>> +{
>>>> + if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
>>>> + ptep_get_and_clear(mm, addr, ptep);
>>>> + else
>>>> + pte_clear(mm, addr, ptep);
>>>
>>> Could not this be reworked to avoid IS_ENABLED() ? This is confusing. If the page
>>> table hooks can be added to all potential page table paths via generic helpers,
>>> irrespective of CONFIG_PAGE_TABLE_CHECK option, there is no rationale for doing
>>> a IS_ENABLED() check here.
>>>
>>
>> From the perspective of code logic, we need to check the pte before being cleared. Whether pte check is required depends on IS_ENABLED().
>>
>> Are there any suggestions for better implementation?
>
> But other generic page table helpers already have page table check hooks
> instrumented without IS_ENABLED() checks, then why this is any different.
>
Maybe i understand what you said, the more reasonable implement is:
static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned
long address, pte_t *ptep)
{
pte_t pte = *ptep;
pte_clear(mm, address, ptep);
page_table_check_pte_clear(mm, address, pte);
return pte;
}
static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
ptep_get_and_clear(mm, address, ptep);
}
>>
>> Thank you,
>> Tong.
>>
>>>> +}
>>>> +#endif
>>>> +
>>>> #ifndef __HAVE_ARCH_PTEP_GET
>>>> static inline pte_t ptep_get(pte_t *ptep)
>>>> {
>>>> @@ -360,7 +365,10 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>>>> pmd_t *pmdp)
>>>> {
>>>> pmd_t pmd = *pmdp;
>>>> +
>>>> pmd_clear(pmdp);
>>>> + page_table_check_pmd_clear(mm, address, pmd);
>>>> +
>>>> return pmd;
>>>> }
>>>> #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
>>>> @@ -372,6 +380,8 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
>>>> pud_t pud = *pudp;
>>>> pud_clear(pudp);
>>>> + page_table_check_pud_clear(mm, address, pud);
>>>> +
>>>> return pud;
>>>> }
>>>> #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
>>> .
> .