Re: powerpc/powernv: copy/paste - Mask XERS0 bit in CR

2018-06-04 Thread Michael Ellerman 
Haren Myneni  writes:
> On 06/03/2018 03:48 AM, Michael Ellerman wrote:
>> Haren Myneni  writes:
>>> NX can set 3rd bit in CR register for XER[SO] (Summation overflow)
>>> which is not related to paste request. The current paste function
>>> returns failure for the successful request when this bit is set.
>>> So mask this bit and check the proper return status.
>>>
>>> Fixes: 2392c8c8c045 ("powerpc/powernv/vas: Define copy/paste interfaces")
>>> Cc: sta...@vger.kernel.org # v4.14+
>>> Signed-off-by: Haren Myneni 
>>>
>>> diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
>>> b/arch/powerpc/platforms/powernv/copy-paste.h
>>> index c9a5036..82392e3 100644
>>> --- a/arch/powerpc/platforms/powernv/copy-paste.h
>>> +++ b/arch/powerpc/platforms/powernv/copy-paste.h
>>> @@ -9,7 +9,8 @@
>>>  #include 
>>>  
>>>  #define CR0_SHIFT  28
>>> -#define CR0_MASK   0xF
>>> +#define CR0_MASK   0xE /* 3rd bit undefined or set for XER[SO] */
>>> +
>>>  /*
>>>   * Copy/paste instructions:
>>>   *
>> 
>> Unfortunately this no longer applies to my next branch, because those
>> macros have been moved out of this header as part of an unrelated patch.
>> 
>> The following patch should work instead, can you please confirm by
>> testing it?
>> 
>> diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
>> b/arch/powerpc/platforms/powernv/copy-paste.h
>> index 3fa62de96d9c..c46a326776cf 100644
>> --- a/arch/powerpc/platforms/powernv/copy-paste.h
>> +++ b/arch/powerpc/platforms/powernv/copy-paste.h
>> @@ -41,5 +41,7 @@ static inline int vas_paste(void *paste_address, int 
>> offset)
>>  : "b" (offset), "b" (paste_address)
>>  : "memory", "cr0");
>> 
>> -return (cr >> CR0_SHIFT) & CR0_MASK;
>> +
>> +/* We mask with 0xE to ignore SO */
>> +return (cr >> CR0_SHIFT) & 0xE;
>>  }
>
> Tested with this patch and it works.

Thanks. I sent a new version to the list and will apply that.

cheers

Re: powerpc/powernv: copy/paste - Mask XERS0 bit in CR

2018-06-03 Thread Haren Myneni 
On 06/03/2018 03:48 AM, Michael Ellerman wrote:
> Hi Haren,
> 
> Haren Myneni  writes:
>> 
>> NX can set 3rd bit in CR register for XER[SO] (Summation overflow)
>> which is not related to paste request. The current paste function
>> returns failure for the successful request when this bit is set.
>> So mask this bit and check the proper return status.
>>
>> Fixes: 2392c8c8c045 ("powerpc/powernv/vas: Define copy/paste interfaces")
>> Cc: sta...@vger.kernel.org # v4.14+
>> Signed-off-by: Haren Myneni 
>>
>> diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
>> b/arch/powerpc/platforms/powernv/copy-paste.h
>> index c9a5036..82392e3 100644
>> --- a/arch/powerpc/platforms/powernv/copy-paste.h
>> +++ b/arch/powerpc/platforms/powernv/copy-paste.h
>> @@ -9,7 +9,8 @@
>>  #include 
>>  
>>  #define CR0_SHIFT   28
>> -#define CR0_MASK0xF
>> +#define CR0_MASK0xE /* 3rd bit undefined or set for XER[SO] */
>> +
>>  /*
>>   * Copy/paste instructions:
>>   *
> 
> Unfortunately this no longer applies to my next branch, because those
> macros have been moved out of this header as part of an unrelated patch.
> 
> The following patch should work instead, can you please confirm by
> testing it?
> 
> diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
> b/arch/powerpc/platforms/powernv/copy-paste.h
> index 3fa62de96d9c..c46a326776cf 100644
> --- a/arch/powerpc/platforms/powernv/copy-paste.h
> +++ b/arch/powerpc/platforms/powernv/copy-paste.h
> @@ -41,5 +41,7 @@ static inline int vas_paste(void *paste_address, int offset)
>   : "b" (offset), "b" (paste_address)
>   : "memory", "cr0");
> 
> - return (cr >> CR0_SHIFT) & CR0_MASK;
> +
> + /* We mask with 0xE to ignore SO */
> + return (cr >> CR0_SHIFT) & 0xE;
>  }
> 
> 

Tested with this patch and it works.

Thanks
Haren

> cheers
>

Re: powerpc/powernv: copy/paste - Mask XERS0 bit in CR

2018-06-03 Thread Michael Ellerman 
Hi Haren,

Haren Myneni  writes:
> 
> NX can set 3rd bit in CR register for XER[SO] (Summation overflow)
> which is not related to paste request. The current paste function
> returns failure for the successful request when this bit is set.
> So mask this bit and check the proper return status.
>
> Fixes: 2392c8c8c045 ("powerpc/powernv/vas: Define copy/paste interfaces")
> Cc: sta...@vger.kernel.org # v4.14+
> Signed-off-by: Haren Myneni 
>
> diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
> b/arch/powerpc/platforms/powernv/copy-paste.h
> index c9a5036..82392e3 100644
> --- a/arch/powerpc/platforms/powernv/copy-paste.h
> +++ b/arch/powerpc/platforms/powernv/copy-paste.h
> @@ -9,7 +9,8 @@
>  #include 
>  
>  #define CR0_SHIFT28
> -#define CR0_MASK 0xF
> +#define CR0_MASK 0xE /* 3rd bit undefined or set for XER[SO] */
> +
>  /*
>   * Copy/paste instructions:
>   *

Unfortunately this no longer applies to my next branch, because those
macros have been moved out of this header as part of an unrelated patch.

The following patch should work instead, can you please confirm by
testing it?

diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
b/arch/powerpc/platforms/powernv/copy-paste.h
index 3fa62de96d9c..c46a326776cf 100644
--- a/arch/powerpc/platforms/powernv/copy-paste.h
+++ b/arch/powerpc/platforms/powernv/copy-paste.h
@@ -41,5 +41,7 @@ static inline int vas_paste(void *paste_address, int offset)
: "b" (offset), "b" (paste_address)
: "memory", "cr0");
 
-   return (cr >> CR0_SHIFT) & CR0_MASK;
+
+   /* We mask with 0xE to ignore SO */
+   return (cr >> CR0_SHIFT) & 0xE;
 }


cheers

powerpc/powernv: copy/paste - Mask XERS0 bit in CR

2018-05-31 Thread Haren Myneni 

NX can set 3rd bit in CR register for XER[SO] (Summation overflow)
which is not related to paste request. The current paste function
returns failure for the successful request when this bit is set.
So mask this bit and check the proper return status.

Fixes: 2392c8c8c045 ("powerpc/powernv/vas: Define copy/paste interfaces")
Cc: sta...@vger.kernel.org # v4.14+
Signed-off-by: Haren Myneni 

diff --git a/arch/powerpc/platforms/powernv/copy-paste.h 
b/arch/powerpc/platforms/powernv/copy-paste.h
index c9a5036..82392e3 100644
--- a/arch/powerpc/platforms/powernv/copy-paste.h
+++ b/arch/powerpc/platforms/powernv/copy-paste.h
@@ -9,7 +9,8 @@
 #include 
 
 #define CR0_SHIFT  28
-#define CR0_MASK   0xF
+#define CR0_MASK   0xE /* 3rd bit undefined or set for XER[SO] */
+
 /*
  * Copy/paste instructions:
  *