Re: [PATCH V6 4/7] sparc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Khalid Aziz <khalid.aziz@oracle.com>]

On 4/13/22 00:22, Anshuman Khandual wrote:
> 
> 
> On 4/13/22 11:43, Christophe Leroy wrote:
>>
>>
>> Le 13/04/2022 à 07:58, Anshuman Khandual a écrit :
>>> This defines and exports a platform specific custom vm_get_page_prot() via
>>> subscribing ARCH_HAS_VM_GET_PAGE_PROT. It localizes arch_vm_get_page_prot()
>>> as sparc_vm_get_page_prot() and moves near vm_get_page_prot().
>>>
>>> Cc: "David S. Miller" <davem@davemloft.net>
>>> Cc: Khalid Aziz <khalid.aziz@oracle.com>
>>> Cc: sparclinux@vger.kernel.org
>>> Cc: linux-kernel@vger.kernel.org
>>> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
>>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>>> ---
>>>    arch/sparc/Kconfig            |  1 +
>>>    arch/sparc/include/asm/mman.h |  6 ------
>>>    arch/sparc/mm/init_64.c       | 13 +++++++++++++
>>>    3 files changed, 14 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
>>> index 9200bc04701c..85b573643af6 100644
>>> --- a/arch/sparc/Kconfig
>>> +++ b/arch/sparc/Kconfig
>>> @@ -84,6 +84,7 @@ config SPARC64
>>>    	select PERF_USE_VMALLOC
>>>    	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>>>    	select HAVE_C_RECORDMCOUNT
>>> +	select ARCH_HAS_VM_GET_PAGE_PROT
>>>    	select HAVE_ARCH_AUDITSYSCALL
>>>    	select ARCH_SUPPORTS_ATOMIC_RMW
>>>    	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
>>> diff --git a/arch/sparc/include/asm/mman.h b/arch/sparc/include/asm/mman.h
>>> index 274217e7ed70..af9c10c83dc5 100644
>>> --- a/arch/sparc/include/asm/mman.h
>>> +++ b/arch/sparc/include/asm/mman.h
>>> @@ -46,12 +46,6 @@ static inline unsigned long sparc_calc_vm_prot_bits(unsigned long prot)
>>>    	}
>>>    }
>>>    
>>> -#define arch_vm_get_page_prot(vm_flags) sparc_vm_get_page_prot(vm_flags)
>>> -static inline pgprot_t sparc_vm_get_page_prot(unsigned long vm_flags)
>>> -{
>>> -	return (vm_flags & VM_SPARC_ADI) ? __pgprot(_PAGE_MCD_4V) : __pgprot(0);
>>> -}
>>> -
>>>    #define arch_validate_prot(prot, addr) sparc_validate_prot(prot, addr)
>>>    static inline int sparc_validate_prot(unsigned long prot, unsigned long addr)
>>>    {
>>> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
>>> index 8b1911591581..dcb17763c1f2 100644
>>> --- a/arch/sparc/mm/init_64.c
>>> +++ b/arch/sparc/mm/init_64.c
>>> @@ -3184,3 +3184,16 @@ void copy_highpage(struct page *to, struct page *from)
>>>    	}
>>>    }
>>>    EXPORT_SYMBOL(copy_highpage);
>>> +
>>> +static pgprot_t sparc_vm_get_page_prot(unsigned long vm_flags)
>>> +{
>>> +	return (vm_flags & VM_SPARC_ADI) ? __pgprot(_PAGE_MCD_4V) : __pgprot(0);
>>> +}
>>> +
>>> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
>>> +{
>>> +	return __pgprot(pgprot_val(protection_map[vm_flags &
>>> +			(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
>>> +			pgprot_val(sparc_vm_get_page_prot(vm_flags)));
>>> +}
>>> +EXPORT_SYMBOL(vm_get_page_prot);
>>
>>
>> sparc is now the only one with two functions. You can most likely do
>> like you did for ARM and POWERPC: merge into a single function:
> 
> I was almost about to do this one as well but as this patch has already been
> reviewed with a tag, just skipped it. I will respin the series once more :)
> 
> Khalid,
> 
> Could I keep your review tag after the following change ?

Hi Anshuman,

Yes, this change makes sense.

--
Khalid

> 
>>
>> pgprot_t vm_get_page_prot(unsigned long vm_flags)
>> {
>> 	unsigned long prot = pgprot_val(protection_map[vm_flags &
>> 		(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);
>>
>> 	if (vm_flags & VM_SPARC_ADI)
>> 		prot |= _PAGE_MCD_4V;
>>
>> 	return __pgprot(prot);
>> }
>> EXPORT_SYMBOL(vm_get_page_prot);
> 
> - Anshuman