Re: [PATCH v2 1/3] powerpc/pseries: Parse control memory access error

[Ganesh <ganeshgr@linux.ibm.com>]

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On 8/24/21 12:09 PM, Michael Ellerman wrote:

> Hi Ganesh,
>
> Some comments below ...
>
> Ganesh Goudar <ganeshgr@linux.ibm.com> writes:
>> Add support to parse and log control memory access
>> error for pseries.
>>
>> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
>> ---
>> v2: No changes in this patch.
>> ---
>>   arch/powerpc/platforms/pseries/ras.c | 21 +++++++++++++++++++++
>>   1 file changed, 21 insertions(+)
>>
>> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
>> index 167f2e1b8d39..608c35cad0c3 100644
>> --- a/arch/powerpc/platforms/pseries/ras.c
>> +++ b/arch/powerpc/platforms/pseries/ras.c
>> @@ -80,6 +80,7 @@ struct pseries_mc_errorlog {
>>   #define MC_ERROR_TYPE_TLB		0x04
>>   #define MC_ERROR_TYPE_D_CACHE		0x05
>>   #define MC_ERROR_TYPE_I_CACHE		0x07
>> +#define MC_ERROR_TYPE_CTRL_MEM_ACCESS	0x08
> ...
>>   
>> +#define MC_ERROR_CTRL_MEM_ACCESS_PTABLE_WALK	0
>> +#define MC_ERROR_CTRL_MEM_ACCESS_OP_ACCESS	1
>
> Where do the above values come from?

It is from latest PAPR that added support for control memory error.

>> +
>>   static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
>>   {
>>   	switch (mlog->error_type) {
>> @@ -112,6 +116,8 @@ static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
>>   	case	MC_ERROR_TYPE_ERAT:
>>   	case	MC_ERROR_TYPE_TLB:
>>   		return (mlog->sub_err_type & 0x03);
>> +	case	MC_ERROR_TYPE_CTRL_MEM_ACCESS:
>> +		return (mlog->sub_err_type & 0x70) >> 4;
> Can you add to the comment above sub_err_type explaining what these bits are.

Sure, for other errors it is explained in pseries_mc_errorlog definition, ill add it there.

>>   	default:
>>   		return 0;
>>   	}
>> @@ -699,6 +705,21 @@ static int mce_handle_err_virtmode(struct pt_regs *regs,
>>   	case MC_ERROR_TYPE_I_CACHE:
>>   		mce_err.error_type = MCE_ERROR_TYPE_ICACHE;
>>   		break;
>> +	case MC_ERROR_TYPE_CTRL_MEM_ACCESS:
>> +		mce_err.error_type = MCE_ERROR_TYPE_RA;
>> +		if (mce_log->sub_err_type & 0x80)
> This appears many times in the file.
>
> Can we add eg. MC_EFFECTIVE_ADDR_PROVIDED?

ok, thanks.

>> +			eaddr = be64_to_cpu(mce_log->effective_address);
>> +		switch (err_sub_type) {
>> +		case MC_ERROR_CTRL_MEM_ACCESS_PTABLE_WALK:
>> +			mce_err.u.ra_error_type =
>> +				MCE_RA_ERROR_PAGE_TABLE_WALK_LOAD_STORE_FOREIGN;
> That name is ridiculously long, but I guess that's not your fault :)
> We can fix it up in a later patch.
>
>> +			break;
>> +		case MC_ERROR_CTRL_MEM_ACCESS_OP_ACCESS:
>> +			mce_err.u.ra_error_type =
>> +				MCE_RA_ERROR_LOAD_STORE_FOREIGN;
>> +			break;
>> +		}
>> +		break;
> cheers

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