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Commit 9ffd6350 authored by Vishal Verma's avatar Vishal Verma Committed by Dan Williams
Browse files

nfit: don't start a full scrub by default for an MCE 



Starting a full Address Range Scrub (ARS) on hitting a memory error
machine check exception may not always be desirable. Provide a way
through sysfs to toggle the behavior between just adding the address
(cache line) where the MCE happened to the poison list and doing a full
scrub. The former (selective insertion of the address) is done
unconditionally.

Cc: linux-acpi@vger.kernel.org
Cc: Linda Knippers <linda.knippers@hpe.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent a0056afe

drivers/acpi/nfit/core.c

+53 −0
Original line number Diff line number Diff line
@@ -878,6 +878,58 @@ static ssize_t revision_show(struct device *dev, 
}

static DEVICE_ATTR_RO(revision);



static ssize_t hw_error_scrub_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);

	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);

	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);



	return sprintf(buf, "%d\n", acpi_desc->scrub_mode);

}



/*

 * The 'hw_error_scrub' attribute can have the following values written to it:

 * '0': Switch to the default mode where an exception will only insert

 *      the address of the memory error into the poison and badblocks lists.

 * '1': Enable a full scrub to happen if an exception for a memory error is

 *      received.

 */

static ssize_t hw_error_scrub_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t size)

{

	struct nvdimm_bus_descriptor *nd_desc;

	ssize_t rc;

	long val;



	rc = kstrtol(buf, 0, &val);

	if (rc)

		return rc;



	device_lock(dev);

	nd_desc = dev_get_drvdata(dev);

	if (nd_desc) {

		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);



		switch (val) {

		case HW_ERROR_SCRUB_ON:

			acpi_desc->scrub_mode = HW_ERROR_SCRUB_ON;

			break;

		case HW_ERROR_SCRUB_OFF:

			acpi_desc->scrub_mode = HW_ERROR_SCRUB_OFF;

			break;

		default:

			rc = -EINVAL;

			break;

		}

	}

	device_unlock(dev);

	if (rc)

		return rc;

	return size;

}

static DEVICE_ATTR_RW(hw_error_scrub);



/*

 * This shows the number of full Address Range Scrubs that have been

 * completed since driver load time. Userspace can wait on this using
@@ -950,6 +1002,7 @@ static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n) 
static struct attribute *acpi_nfit_attributes[] = {

	&dev_attr_revision.attr,

	&dev_attr_scrub.attr,

	&dev_attr_hw_error_scrub.attr,

	NULL,

};

drivers/acpi/nfit/mce.c

+19 −5
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 */

#include <linux/notifier.h>

#include <linux/acpi.h>

#include <linux/nd.h>

#include <asm/mce.h>

#include "nfit.h"
@@ -62,13 +63,26 @@ static int nfit_handle_mce(struct notifier_block *nb, unsigned long val, 
		}

		mutex_unlock(&acpi_desc->init_mutex);



		if (!found_match)

			continue;



		/* If this fails due to an -ENOMEM, there is little we can do */

		nvdimm_bus_add_poison(acpi_desc->nvdimm_bus,

				ALIGN(mce->addr, L1_CACHE_BYTES),

				L1_CACHE_BYTES);

		nvdimm_region_notify(nfit_spa->nd_region,

				NVDIMM_REVALIDATE_POISON);



		if (acpi_desc->scrub_mode == HW_ERROR_SCRUB_ON) {

			/*

		 * We can ignore an -EBUSY here because if an ARS is already

		 * in progress, just let that be the last authoritative one

			 * We can ignore an -EBUSY here because if an ARS is

			 * already in progress, just let that be the last

			 * authoritative one

			 */

		if (found_match)

			acpi_nfit_ars_rescan(acpi_desc);

		}

		break;

	}



	mutex_unlock(&acpi_desc_lock);

	return NOTIFY_DONE;

drivers/acpi/nfit/nfit.h

+6 −0
Original line number Diff line number Diff line
@@ -161,6 +161,7 @@ struct acpi_nfit_desc { 
	struct list_head list;

	struct kernfs_node *scrub_count_state;

	unsigned int scrub_count;

	unsigned int scrub_mode;

	unsigned int cancel:1;

	unsigned long dimm_cmd_force_en;

	unsigned long bus_cmd_force_en;
@@ -168,6 +169,11 @@ struct acpi_nfit_desc { 
			void *iobuf, u64 len, int rw);

};



enum scrub_mode {

	HW_ERROR_SCRUB_OFF,

	HW_ERROR_SCRUB_ON,

};



enum nd_blk_mmio_selector {

	BDW,

	DCR,