2 files changed, 545 insertions, 7 deletions

diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h b/arch/powerpc/include/uapi/asm/papr_pdsm.h
new file mode 100644
index 000000000000..9ccecc1d6840
--- /dev/null
+++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * PAPR nvDimm Specific Methods (PDSM) and structs for libndctl
+ *
+ * (C) Copyright IBM 2020
+ *
+ * Author: Vaibhav Jain <vaibhav at linux.ibm.com>
+ */
+
+#ifndef _UAPI_ASM_POWERPC_PAPR_PDSM_H_
+#define _UAPI_ASM_POWERPC_PAPR_PDSM_H_
+
+#include <linux/types.h>
+#include <linux/ndctl.h>
+
+/*
+ * PDSM Envelope:
+ *
+ * The ioctl ND_CMD_CALL exchange data between user-space and kernel via
+ * envelope which consists of 2 headers sections and payload sections as
+ * illustrated below:
+ *  +-----------------+---------------+---------------------------+
+ *  |   64-Bytes      |   8-Bytes     |       Max 184-Bytes       |
+ *  +-----------------+---------------+---------------------------+
+ *  | ND-HEADER       |  PDSM-HEADER  |      PDSM-PAYLOAD         |
+ *  +-----------------+---------------+---------------------------+
+ *  | nd_family       |               |                           |
+ *  | nd_size_out     | cmd_status    |                           |
+ *  | nd_size_in      | reserved      |     nd_pdsm_payload       |
+ *  | nd_command      | payload   --> |                           |
+ *  | nd_fw_size      |               |                           |
+ *  | nd_payload ---> |               |                           |
+ *  +---------------+-----------------+---------------------------+
+ *
+ * ND Header:
+ * This is the generic libnvdimm header described as 'struct nd_cmd_pkg'
+ * which is interpreted by libnvdimm before passed on to papr_scm. Important
+ * member fields used are:
+ * 'nd_family'		: (In) NVDIMM_FAMILY_PAPR_SCM
+ * 'nd_size_in'		: (In) PDSM-HEADER + PDSM-IN-PAYLOAD (usually 0)
+ * 'nd_size_out'        : (In) PDSM-HEADER + PDSM-RETURN-PAYLOAD
+ * 'nd_command'         : (In) One of PAPR_PDSM_XXX
+ * 'nd_fw_size'         : (Out) PDSM-HEADER + size of actual payload returned
+ *
+ * PDSM Header:
+ * This is papr-scm specific header that precedes the payload. This is defined
+ * as nd_cmd_pdsm_pkg.  Following fields aare available in this header:
+ *
+ * 'cmd_status'		: (Out) Errors if any encountered while servicing PDSM.
+ * 'reserved'		: Not used, reserved for future and should be set to 0.
+ * 'payload'            : A union of all the possible payload structs
+ *
+ * PDSM Payload:
+ *
+ * The layout of the PDSM Payload is defined by various structs shared between
+ * papr_scm and libndctl so that contents of payload can be interpreted. As such
+ * its defined as a union of all possible payload structs as
+ * 'union nd_pdsm_payload'. Based on the value of 'nd_cmd_pkg.nd_command'
+ * appropriate member of the union is accessed.
+ */
+
+/* Max payload size that we can handle */
+#define ND_PDSM_PAYLOAD_MAX_SIZE 184
+
+/* Max payload size that we can handle */
+#define ND_PDSM_HDR_SIZE \
+	(sizeof(struct nd_pkg_pdsm) - ND_PDSM_PAYLOAD_MAX_SIZE)
+
+/* Various nvdimm health indicators */
+#define PAPR_PDSM_DIMM_HEALTHY       0
+#define PAPR_PDSM_DIMM_UNHEALTHY     1
+#define PAPR_PDSM_DIMM_CRITICAL      2
+#define PAPR_PDSM_DIMM_FATAL         3
+
+/*
+ * Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH
+ * Various flags indicate the health status of the dimm.
+ *
+ * extension_flags	: Any extension fields present in the struct.
+ * dimm_unarmed		: Dimm not armed. So contents wont persist.
+ * dimm_bad_shutdown	: Previous shutdown did not persist contents.
+ * dimm_bad_restore	: Contents from previous shutdown werent restored.
+ * dimm_scrubbed	: Contents of the dimm have been scrubbed.
+ * dimm_locked		: Contents of the dimm cant be modified until CEC reboot
+ * dimm_encrypted	: Contents of dimm are encrypted.
+ * dimm_health		: Dimm health indicator. One of PAPR_PDSM_DIMM_XXXX
+ */
+struct nd_papr_pdsm_health {
+	union {
+		struct {
+			__u32 extension_flags;
+			__u8 dimm_unarmed;
+			__u8 dimm_bad_shutdown;
+			__u8 dimm_bad_restore;
+			__u8 dimm_scrubbed;
+			__u8 dimm_locked;
+			__u8 dimm_encrypted;
+			__u16 dimm_health;
+		};
+		__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
+	};
+};
+
+/*
+ * Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
+ * via 'nd_cmd_pkg.nd_command' member of the ioctl struct
+ */
+enum papr_pdsm {
+	PAPR_PDSM_MIN = 0x0,
+	PAPR_PDSM_HEALTH,
+	PAPR_PDSM_MAX,
+};
+
+/* Maximal union that can hold all possible payload types */
+union nd_pdsm_payload {
+	struct nd_papr_pdsm_health health;
+	__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
+} __packed;
+
+/*
+ * PDSM-header + payload expected with ND_CMD_CALL ioctl from libnvdimm
+ * Valid member of union 'payload' is identified via 'nd_cmd_pkg.nd_command'
+ * that should always precede this struct when sent to papr_scm via CMD_CALL
+ * interface.
+ */
+struct nd_pkg_pdsm {
+	__s32 cmd_status;	/* Out: Sub-cmd status returned back */
+	__u16 reserved[2];	/* Ignored and to be set as '0' */
+	union nd_pdsm_payload payload;
+} __packed;
+
+#endif /* _UAPI_ASM_POWERPC_PAPR_PDSM_H_ */
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index f35592423380..9c569078a09f 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -12,16 +12,57 @@
 #include <linux/libnvdimm.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
+#include <linux/seq_buf.h>
 
 #include <asm/plpar_wrappers.h>
+#include <asm/papr_pdsm.h>
 
 #define BIND_ANY_ADDR (~0ul)
 
 #define PAPR_SCM_DIMM_CMD_MASK \
 	((1ul << ND_CMD_GET_CONFIG_SIZE) | \
 	 (1ul << ND_CMD_GET_CONFIG_DATA) | \
-	 (1ul << ND_CMD_SET_CONFIG_DATA))
-
+	 (1ul << ND_CMD_SET_CONFIG_DATA) | \
+	 (1ul << ND_CMD_CALL))
+
+/* DIMM health bitmap bitmap indicators */
+/* SCM device is unable to persist memory contents */
+#define PAPR_PMEM_UNARMED                   (1ULL << (63 - 0))
+/* SCM device failed to persist memory contents */
+#define PAPR_PMEM_SHUTDOWN_DIRTY            (1ULL << (63 - 1))
+/* SCM device contents are persisted from previous IPL */
+#define PAPR_PMEM_SHUTDOWN_CLEAN            (1ULL << (63 - 2))
+/* SCM device contents are not persisted from previous IPL */
+#define PAPR_PMEM_EMPTY                     (1ULL << (63 - 3))
+/* SCM device memory life remaining is critically low */
+#define PAPR_PMEM_HEALTH_CRITICAL           (1ULL << (63 - 4))
+/* SCM device will be garded off next IPL due to failure */
+#define PAPR_PMEM_HEALTH_FATAL              (1ULL << (63 - 5))
+/* SCM contents cannot persist due to current platform health status */
+#define PAPR_PMEM_HEALTH_UNHEALTHY          (1ULL << (63 - 6))
+/* SCM device is unable to persist memory contents in certain conditions */
+#define PAPR_PMEM_HEALTH_NON_CRITICAL       (1ULL << (63 - 7))
+/* SCM device is encrypted */
+#define PAPR_PMEM_ENCRYPTED                 (1ULL << (63 - 8))
+/* SCM device has been scrubbed and locked */
+#define PAPR_PMEM_SCRUBBED_AND_LOCKED       (1ULL << (63 - 9))
+
+/* Bits status indicators for health bitmap indicating unarmed dimm */
+#define PAPR_PMEM_UNARMED_MASK (PAPR_PMEM_UNARMED |		\
+				PAPR_PMEM_HEALTH_UNHEALTHY)
+
+/* Bits status indicators for health bitmap indicating unflushed dimm */
+#define PAPR_PMEM_BAD_SHUTDOWN_MASK (PAPR_PMEM_SHUTDOWN_DIRTY)
+
+/* Bits status indicators for health bitmap indicating unrestored dimm */
+#define PAPR_PMEM_BAD_RESTORE_MASK  (PAPR_PMEM_EMPTY)
+
+/* Bit status indicators for smart event notification */
+#define PAPR_PMEM_SMART_EVENT_MASK (PAPR_PMEM_HEALTH_CRITICAL | \
+				    PAPR_PMEM_HEALTH_FATAL |	\
+				    PAPR_PMEM_HEALTH_UNHEALTHY)
+
+/* private struct associated with each region */
 struct papr_scm_priv {
 	struct platform_device *pdev;
 	struct device_node *dn;
@@ -39,6 +80,15 @@ struct papr_scm_priv {
 	struct resource res;
 	struct nd_region *region;
 	struct nd_interleave_set nd_set;
+
+	/* Protect dimm health data from concurrent read/writes */
+	struct mutex health_mutex;
+
+	/* Last time the health information of the dimm was updated */
+	unsigned long lasthealth_jiffies;
+
+	/* Health information for the dimm */
+	u64 health_bitmap;
 };
 
 static int drc_pmem_bind(struct papr_scm_priv *p)
@@ -144,6 +194,61 @@ err_out:
 	return drc_pmem_bind(p);
 }
 
+/*
+ * Issue hcall to retrieve dimm health info and populate papr_scm_priv with the
+ * health information.
+ */
+static int __drc_pmem_query_health(struct papr_scm_priv *p)
+{
+	unsigned long ret[PLPAR_HCALL_BUFSIZE];
+	long rc;
+
+	/* issue the hcall */
+	rc = plpar_hcall(H_SCM_HEALTH, ret, p->drc_index);
+	if (rc != H_SUCCESS) {
+		dev_err(&p->pdev->dev,
+			"Failed to query health information, Err:%ld\n", rc);
+		return -ENXIO;
+	}
+
+	p->lasthealth_jiffies = jiffies;
+	p->health_bitmap = ret[0] & ret[1];
+
+	dev_dbg(&p->pdev->dev,
+		"Queried dimm health info. Bitmap:0x%016lx Mask:0x%016lx\n",
+		ret[0], ret[1]);
+
+	return 0;
+}
+
+/* Min interval in seconds for assuming stable dimm health */
+#define MIN_HEALTH_QUERY_INTERVAL 60
+
+/* Query cached health info and if needed call drc_pmem_query_health */
+static int drc_pmem_query_health(struct papr_scm_priv *p)
+{
+	unsigned long cache_timeout;
+	int rc;
+
+	/* Protect concurrent modifications to papr_scm_priv */
+	rc = mutex_lock_interruptible(&p->health_mutex);
+	if (rc)
+		return rc;
+
+	/* Jiffies offset for which the health data is assumed to be same */
+	cache_timeout = p->lasthealth_jiffies +
+		msecs_to_jiffies(MIN_HEALTH_QUERY_INTERVAL * 1000);
+
+	/* Fetch new health info is its older than MIN_HEALTH_QUERY_INTERVAL */
+	if (time_after(jiffies, cache_timeout))
+		rc = __drc_pmem_query_health(p);
+	else
+		/* Assume cached health data is valid */
+		rc = 0;
+
+	mutex_unlock(&p->health_mutex);
+	return rc;
+}
 
 static int papr_scm_meta_get(struct papr_scm_priv *p,
 			     struct nd_cmd_get_config_data_hdr *hdr)
@@ -246,16 +351,250 @@ static int papr_scm_meta_set(struct papr_scm_priv *p,
 	return 0;
 }
 
+/*
+ * Do a sanity checks on the inputs args to dimm-control function and return
+ * '0' if valid. Validation of PDSM payloads happens later in
+ * papr_scm_service_pdsm.
+ */
+static int is_cmd_valid(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+			unsigned int buf_len)
+{
+	unsigned long cmd_mask = PAPR_SCM_DIMM_CMD_MASK;
+	struct nd_cmd_pkg *nd_cmd;
+	struct papr_scm_priv *p;
+	enum papr_pdsm pdsm;
+
+	/* Only dimm-specific calls are supported atm */
+	if (!nvdimm)
+		return -EINVAL;
+
+	/* get the provider data from struct nvdimm */
+	p = nvdimm_provider_data(nvdimm);
+
+	if (!test_bit(cmd, &cmd_mask)) {
+		dev_dbg(&p->pdev->dev, "Unsupported cmd=%u\n", cmd);
+		return -EINVAL;
+	}
+
+	/* For CMD_CALL verify pdsm request */
+	if (cmd == ND_CMD_CALL) {
+		/* Verify the envelope and envelop size */
+		if (!buf ||
+		    buf_len < (sizeof(struct nd_cmd_pkg) + ND_PDSM_HDR_SIZE)) {
+			dev_dbg(&p->pdev->dev, "Invalid pkg size=%u\n",
+				buf_len);
+			return -EINVAL;
+		}
+
+		/* Verify that the nd_cmd_pkg.nd_family is correct */
+		nd_cmd = (struct nd_cmd_pkg *)buf;
+
+		if (nd_cmd->nd_family != NVDIMM_FAMILY_PAPR) {
+			dev_dbg(&p->pdev->dev, "Invalid pkg family=0x%llx\n",
+				nd_cmd->nd_family);
+			return -EINVAL;
+		}
+
+		pdsm = (enum papr_pdsm)nd_cmd->nd_command;
+
+		/* Verify if the pdsm command is valid */
+		if (pdsm <= PAPR_PDSM_MIN || pdsm >= PAPR_PDSM_MAX) {
+			dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid PDSM\n",
+				pdsm);
+			return -EINVAL;
+		}
+
+		/* Have enough space to hold returned 'nd_pkg_pdsm' header */
+		if (nd_cmd->nd_size_out < ND_PDSM_HDR_SIZE) {
+			dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid payload\n",
+				pdsm);
+			return -EINVAL;
+		}
+	}
+
+	/* Let the command be further processed */
+	return 0;
+}
+
+/* Fetch the DIMM health info and populate it in provided package. */
+static int papr_pdsm_health(struct papr_scm_priv *p,
+			    union nd_pdsm_payload *payload)
+{
+	int rc;
+
+	/* Ensure dimm health mutex is taken preventing concurrent access */
+	rc = mutex_lock_interruptible(&p->health_mutex);
+	if (rc)
+		goto out;
+
+	/* Always fetch upto date dimm health data ignoring cached values */
+	rc = __drc_pmem_query_health(p);
+	if (rc) {
+		mutex_unlock(&p->health_mutex);
+		goto out;
+	}
+
+	/* update health struct with various flags derived from health bitmap */
+	payload->health = (struct nd_papr_pdsm_health) {
+		.extension_flags = 0,
+		.dimm_unarmed = !!(p->health_bitmap & PAPR_PMEM_UNARMED_MASK),
+		.dimm_bad_shutdown = !!(p->health_bitmap & PAPR_PMEM_BAD_SHUTDOWN_MASK),
+		.dimm_bad_restore = !!(p->health_bitmap & PAPR_PMEM_BAD_RESTORE_MASK),
+		.dimm_scrubbed = !!(p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED),
+		.dimm_locked = !!(p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED),
+		.dimm_encrypted = !!(p->health_bitmap & PAPR_PMEM_ENCRYPTED),
+		.dimm_health = PAPR_PDSM_DIMM_HEALTHY,
+	};
+
+	/* Update field dimm_health based on health_bitmap flags */
+	if (p->health_bitmap & PAPR_PMEM_HEALTH_FATAL)
+		payload->health.dimm_health = PAPR_PDSM_DIMM_FATAL;
+	else if (p->health_bitmap & PAPR_PMEM_HEALTH_CRITICAL)
+		payload->health.dimm_health = PAPR_PDSM_DIMM_CRITICAL;
+	else if (p->health_bitmap & PAPR_PMEM_HEALTH_UNHEALTHY)
+		payload->health.dimm_health = PAPR_PDSM_DIMM_UNHEALTHY;
+
+	/* struct populated hence can release the mutex now */
+	mutex_unlock(&p->health_mutex);
+	rc = sizeof(struct nd_papr_pdsm_health);
+
+out:
+	return rc;
+}
+
+/*
+ * 'struct pdsm_cmd_desc'
+ * Identifies supported PDSMs' expected length of in/out payloads
+ * and pdsm service function.
+ *
+ * size_in	: Size of input payload if any in the PDSM request.
+ * size_out	: Size of output payload if any in the PDSM request.
+ * service	: Service function for the PDSM request. Return semantics:
+ *		  rc < 0 : Error servicing PDSM and rc indicates the error.
+ *		  rc >=0 : Serviced successfully and 'rc' indicate number of
+ *			bytes written to payload.
+ */
+struct pdsm_cmd_desc {
+	u32 size_in;
+	u32 size_out;
+	int (*service)(struct papr_scm_priv *dimm,
+		       union nd_pdsm_payload *payload);
+};
+
+/* Holds all supported PDSMs' command descriptors */
+static const struct pdsm_cmd_desc __pdsm_cmd_descriptors[] = {
+	[PAPR_PDSM_MIN] = {
+		.size_in = 0,
+		.size_out = 0,
+		.service = NULL,
+	},
+	/* New PDSM command descriptors to be added below */
+
+	[PAPR_PDSM_HEALTH] = {
+		.size_in = 0,
+		.size_out = sizeof(struct nd_papr_pdsm_health),
+		.service = papr_pdsm_health,
+	},
+	/* Empty */
+	[PAPR_PDSM_MAX] = {
+		.size_in = 0,
+		.size_out = 0,
+		.service = NULL,
+	},
+};
+
+/* Given a valid pdsm cmd return its command descriptor else return NULL */
+static inline const struct pdsm_cmd_desc *pdsm_cmd_desc(enum papr_pdsm cmd)
+{
+	if (cmd >= 0 || cmd < ARRAY_SIZE(__pdsm_cmd_descriptors))
+		return &__pdsm_cmd_descriptors[cmd];
+
+	return NULL;
+}
+
+/*
+ * For a given pdsm request call an appropriate service function.
+ * Returns errors if any while handling the pdsm command package.
+ */
+static int papr_scm_service_pdsm(struct papr_scm_priv *p,
+				 struct nd_cmd_pkg *pkg)
+{
+	/* Get the PDSM header and PDSM command */
+	struct nd_pkg_pdsm *pdsm_pkg = (struct nd_pkg_pdsm *)pkg->nd_payload;
+	enum papr_pdsm pdsm = (enum papr_pdsm)pkg->nd_command;
+	const struct pdsm_cmd_desc *pdsc;
+	int rc;
+
+	/* Fetch corresponding pdsm descriptor for validation and servicing */
+	pdsc = pdsm_cmd_desc(pdsm);
+
+	/* Validate pdsm descriptor */
+	/* Ensure that reserved fields are 0 */
+	if (pdsm_pkg->reserved[0] || pdsm_pkg->reserved[1]) {
+		dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Invalid reserved field\n",
+			pdsm);
+		return -EINVAL;
+	}
+
+	/* If pdsm expects some input, then ensure that the size_in matches */
+	if (pdsc->size_in &&
+	    pkg->nd_size_in != (pdsc->size_in + ND_PDSM_HDR_SIZE)) {
+		dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Mismatched size_in=%d\n",
+			pdsm, pkg->nd_size_in);
+		return -EINVAL;
+	}
+
+	/* If pdsm wants to return data, then ensure that  size_out matches */
+	if (pdsc->size_out &&
+	    pkg->nd_size_out != (pdsc->size_out + ND_PDSM_HDR_SIZE)) {
+		dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Mismatched size_out=%d\n",
+			pdsm, pkg->nd_size_out);
+		return -EINVAL;
+	}
+
+	/* Service the pdsm */
+	if (pdsc->service) {
+		dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Servicing..\n", pdsm);
+
+		rc = pdsc->service(p, &pdsm_pkg->payload);
+
+		if (rc < 0) {
+			/* error encountered while servicing pdsm */
+			pdsm_pkg->cmd_status = rc;
+			pkg->nd_fw_size = ND_PDSM_HDR_SIZE;
+		} else {
+			/* pdsm serviced and 'rc' bytes written to payload */
+			pdsm_pkg->cmd_status = 0;
+			pkg->nd_fw_size = ND_PDSM_HDR_SIZE + rc;
+		}
+	} else {
+		dev_dbg(&p->pdev->dev, "PDSM[0x%x]: Unsupported PDSM request\n",
+			pdsm);
+		pdsm_pkg->cmd_status = -ENOENT;
+		pkg->nd_fw_size = ND_PDSM_HDR_SIZE;
+	}
+
+	return pdsm_pkg->cmd_status;
+}
+
 static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
 			  struct nvdimm *nvdimm, unsigned int cmd, void *buf,
 			  unsigned int buf_len, int *cmd_rc)
 {
 	struct nd_cmd_get_config_size *get_size_hdr;
+	struct nd_cmd_pkg *call_pkg = NULL;
 	struct papr_scm_priv *p;
+	int rc;
 
-	/* Only dimm-specific calls are supported atm */
-	if (!nvdimm)
-		return -EINVAL;
+	rc = is_cmd_valid(nvdimm, cmd, buf, buf_len);
+	if (rc) {
+		pr_debug("Invalid cmd=0x%x. Err=%d\n", cmd, rc);
+		return rc;
+	}
+
+	/* Use a local variable in case cmd_rc pointer is NULL */
+	if (!cmd_rc)
+		cmd_rc = &rc;
 
 	p = nvdimm_provider_data(nvdimm);
 
@@ -277,7 +616,13 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
 		*cmd_rc = papr_scm_meta_set(p, buf);
 		break;
 
+	case ND_CMD_CALL:
+		call_pkg = (struct nd_cmd_pkg *)buf;
+		*cmd_rc = papr_scm_service_pdsm(p, call_pkg);
+		break;
+
 	default:
+		dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd);
 		return -EINVAL;
 	}
 
@@ -286,6 +631,64 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
 	return 0;
 }
 
+static ssize_t flags_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *dimm = to_nvdimm(dev);
+	struct papr_scm_priv *p = nvdimm_provider_data(dimm);
+	struct seq_buf s;
+	u64 health;
+	int rc;
+
+	rc = drc_pmem_query_health(p);
+	if (rc)
+		return rc;
+
+	/* Copy health_bitmap locally, check masks & update out buffer */
+	health = READ_ONCE(p->health_bitmap);
+
+	seq_buf_init(&s, buf, PAGE_SIZE);
+	if (health & PAPR_PMEM_UNARMED_MASK)
+		seq_buf_printf(&s, "not_armed ");
+
+	if (health & PAPR_PMEM_BAD_SHUTDOWN_MASK)
+		seq_buf_printf(&s, "flush_fail ");
+
+	if (health & PAPR_PMEM_BAD_RESTORE_MASK)
+		seq_buf_printf(&s, "restore_fail ");
+
+	if (health & PAPR_PMEM_ENCRYPTED)
+		seq_buf_printf(&s, "encrypted ");
+
+	if (health & PAPR_PMEM_SMART_EVENT_MASK)
+		seq_buf_printf(&s, "smart_notify ");
+
+	if (health & PAPR_PMEM_SCRUBBED_AND_LOCKED)
+		seq_buf_printf(&s, "scrubbed locked ");
+
+	if (seq_buf_used(&s))
+		seq_buf_printf(&s, "\n");
+
+	return seq_buf_used(&s);
+}
+DEVICE_ATTR_RO(flags);
+
+/* papr_scm specific dimm attributes */
+static struct attribute *papr_nd_attributes[] = {
+	&dev_attr_flags.attr,
+	NULL,
+};
+
+static struct attribute_group papr_nd_attribute_group = {
+	.name = "papr",
+	.attrs = papr_nd_attributes,
+};
+
+static const struct attribute_group *papr_nd_attr_groups[] = {
+	&papr_nd_attribute_group,
+	NULL,
+};
+
 static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 {
 	struct device *dev = &p->pdev->dev;
@@ -312,8 +715,8 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	dimm_flags = 0;
 	set_bit(NDD_LABELING, &dimm_flags);
 
-	p->nvdimm = nvdimm_create(p->bus, p, NULL, dimm_flags,
-				  PAPR_SCM_DIMM_CMD_MASK, 0, NULL);
+	p->nvdimm = nvdimm_create(p->bus, p, papr_nd_attr_groups,
+				  dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL);
 	if (!p->nvdimm) {
 		dev_err(dev, "Error creating DIMM object for %pOF\n", p->dn);
 		goto err;
@@ -399,6 +802,9 @@ static int papr_scm_probe(struct platform_device *pdev)
 	if (!p)
 		return -ENOMEM;
 
+	/* Initialize the dimm mutex */
+	mutex_init(&p->health_mutex);
+
 	/* optional DT properties */
 	of_property_read_u32(dn, "ibm,metadata-size", &metadata_size);