[PATCH] papr/scm: Add bad memory ranges to nvdimm bad ranges

[Santosh Sivaraj]

Mahesh J Salgaonkar <mahesh at linux.ibm.com> writes:

> On 2020-04-01 13:17:41 Wed, Santosh Sivaraj wrote:
>> Subscribe to the MCE notification and add the physical address which
>> generated a memory error to nvdimm bad range.
>> 
>> Signed-off-by: Santosh Sivaraj <santosh at fossix.org>
>> ---
>> 
>> This patch depends on "powerpc/mce: Add MCE notification chain" [1].
>> 
>> Unlike the previous series[2], the patch adds badblock registration only for
>> pseries scm driver. Handling badblocks for baremetal (powernv) PMEM will be done
>> later and if possible get the badblock handling as a common code.
>> 
>> [1] https://lore.kernel.org/linuxppc-dev/20200330071219.12284-1-ganeshgr@linux.ibm.com/
>> [2] https://lore.kernel.org/linuxppc-dev/20190820023030.18232-1-santosh@fossix.org/
>> 
>> arch/powerpc/platforms/pseries/papr_scm.c | 96 ++++++++++++++++++++++-
>>  1 file changed, 95 insertions(+), 1 deletion(-)
>> 
>> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
>> index 0b4467e378e5..5012cbf4606e 100644
>> --- a/arch/powerpc/platforms/pseries/papr_scm.c
>> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> [...]
>> +static int handle_mce_ue(struct notifier_block *nb, unsigned long val,
>> +			 void *data)
>> +{
>> +	struct machine_check_event *evt = data;
>> +	struct papr_scm_priv *p;
>> +	u64 phys_addr;
>> +	bool found = false;
>> +
>> +	if (evt->error_type != MCE_ERROR_TYPE_UE)
>> +		return NOTIFY_DONE;
>> +
>> +	if (list_empty(&papr_nd_regions))
>> +		return NOTIFY_DONE;
>
> Do you really need this check ?

Quite harmless I guess, atleast it saves a branch and mutex_lock/unlock.

>
>> +
>> +	phys_addr = evt->u.ue_error.physical_address +
>> +		(evt->u.ue_error.effective_address & ~PAGE_MASK);
>> +
>> +	if (!evt->u.ue_error.physical_address_provided ||
>> +	    !is_zone_device_page(pfn_to_page(phys_addr >> PAGE_SHIFT)))
>> +		return NOTIFY_DONE;
>> +
>> +	/* mce notifier is called from a process context, so mutex is safe */
>> +	mutex_lock(&papr_ndr_lock);
>> +	list_for_each_entry(p, &papr_nd_regions, region_list) {
>> +		struct resource res = p->res;
>> +
>> +		if (phys_addr >= res.start && phys_addr <= res.end) {
>> +			found = true;
>> +			break;
>> +		}
>> +	}
>> +
>> +	mutex_unlock(&papr_ndr_lock);
>> +
>> +	if (!found)
>> +		return NOTIFY_DONE;
>> +
>> +	papr_scm_add_badblock(p->region, p->bus, phys_addr);
>> +
>> +	return NOTIFY_OK;
>> +}
>> +
>> +static struct notifier_block mce_ue_nb = {
>> +	.notifier_call = handle_mce_ue
>> +};
>> +
> [...]
>> -module_platform_driver(papr_scm_driver);
>> +static int __init papr_scm_init(void)
>> +{
>> +	int ret;
>> +
>> +	ret = platform_driver_register(&papr_scm_driver);
>> +	if (!ret)
>> +		mce_register_notifier(&mce_ue_nb);
>> +
>> +	return ret;
>> +}
>> +module_init(papr_scm_init);
>> +
>> +static void __exit papr_scm_exit(void)
>> +{
>> +	mce_unregister_notifier(&mce_ue_nb);
>> +	platform_driver_unregister(&papr_scm_driver);
>> +}
>> +module_exit(papr_scm_exit);
>
> Rest Looks good to me.
>
> Reviewed-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>

Thanks for the review.

Santosh
>
> Thanks,
> -Mahesh.
>
>> +
>>  MODULE_DEVICE_TABLE(of, papr_scm_match);
>>  MODULE_LICENSE("GPL");
>>  MODULE_AUTHOR("IBM Corporation");
>> -- 
>> 2.25.1
>> 
>
> -- 
> Mahesh J Salgaonkar