Re: [PATCH 1/2] powerpc/mm/keys: Move pte bits to correct headers

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On 03/08/2018 01:58 AM, Ram Pai wrote:
> On Wed, Mar 07, 2018 at 07:06:44PM +0530, Aneesh Kumar K.V wrote:
>> Memory keys are supported only with hash translation mode. Instead of #ifdef in
>> generic code move the key related pte bits to respective headers
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
>>   arch/powerpc/include/asm/book3s/64/hash-4k.h  |  7 +++++++
>>   arch/powerpc/include/asm/book3s/64/hash-64k.h |  7 +++++++
>>   arch/powerpc/include/asm/book3s/64/pgtable.h  | 19 -------------------
>>   3 files changed, 14 insertions(+), 19 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
>> index fc3dc6a93939..4103bfc7c223 100644
>> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
>> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
>> @@ -33,6 +33,13 @@
>>   #define H_PAGE_THP_HUGE 0x0
>>   #define H_PAGE_COMBO	0x0
>>
>> +/* memory key bits, only 8 keys supported */
>> +#define H_PTE_PKEY_BIT0	0
>> +#define H_PTE_PKEY_BIT1	0
>> +#define H_PTE_PKEY_BIT2	_RPAGE_RSV3
>> +#define H_PTE_PKEY_BIT3	_RPAGE_RSV4
>> +#define H_PTE_PKEY_BIT4	_RPAGE_RSV5
>> +
> 
> 
> If CONFIG_PPC_MEM_KEYS is not defined, all of them have to be 0.  How is
> that handled here?

why? conditional defines of pte bits always results in error, like we 
check for an overloaded key bit in some code path and taking wrong action.

> 
>>   /* 8 bytes per each pte entry */
>>   #define H_PTE_FRAG_SIZE_SHIFT  (H_PTE_INDEX_SIZE + 3)
>>   #define H_PTE_FRAG_NR	(PAGE_SIZE >> H_PTE_FRAG_SIZE_SHIFT)
>> diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
>> index e53728ff29a0..bb880c97b87d 100644
>> --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
>> +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
>> @@ -16,6 +16,13 @@
>>   #define H_PAGE_BUSY	_RPAGE_RPN44     /* software: PTE & hash are busy */
>>   #define H_PAGE_HASHPTE	_RPAGE_RPN43	/* PTE has associated HPTE */
>>
>> +/* memory key bits. */
>> +#define H_PTE_PKEY_BIT0	_RPAGE_RSV1
>> +#define H_PTE_PKEY_BIT1	_RPAGE_RSV2
>> +#define H_PTE_PKEY_BIT2	_RPAGE_RSV3
>> +#define H_PTE_PKEY_BIT3	_RPAGE_RSV4
>> +#define H_PTE_PKEY_BIT4	_RPAGE_RSV5
>> +
> 
> same comment as above.
> 

-aneesh