Commit b791abf3 authored by Vaibhav Jain's avatar Vaibhav Jain Committed by Dan Williams
Browse files

powerpc/papr_scm: Fetch nvdimm health information from PHYP 



Implement support for fetching nvdimm health information via
H_SCM_HEALTH hcall as documented in Ref[1]. The hcall returns a pair
of 64-bit bitmap, bitwise-and of which is then stored in
'struct papr_scm_priv' and subsequently partially exposed to
user-space via newly introduced dimm specific attribute
'papr/flags'. Since the hcall is costly, the health information is
cached and only re-queried, 60s after the previous successful hcall.

The patch also adds a  documentation text describing flags reported by
the the new sysfs attribute 'papr/flags' is also introduced at
Documentation/ABI/testing/sysfs-bus-papr-pmem.

[1] commit 58b278f5 ("powerpc: Provide initial documentation for
PAPR hcalls")

Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200615124407.32596-4-vaibhav@linux.ibm.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 97c02c72

Documentation/ABI/testing/sysfs-bus-papr-pmem

0 → 100644
+27 −0
Original line number Diff line number Diff line 
What:		/sys/bus/nd/devices/nmemX/papr/flags

Date:		Apr, 2020

KernelVersion:	v5.8

Contact:	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, linux-nvdimm@lists.01.org,

Description:

		(RO) Report flags indicating various states of a

		papr-pmem NVDIMM device. Each flag maps to a one or

		more bits set in the dimm-health-bitmap retrieved in

		response to H_SCM_HEALTH hcall. The details of the bit

		flags returned in response to this hcall is available

		at 'Documentation/powerpc/papr_hcalls.rst' . Below are

		the flags reported in this sysfs file:



		* "not_armed"	: Indicates that NVDIMM contents will not

				  survive a power cycle.

		* "flush_fail"	: Indicates that NVDIMM contents

				  couldn't be flushed during last

				  shut-down event.

		* "restore_fail": Indicates that NVDIMM contents

				  couldn't be restored during NVDIMM

				  initialization.

		* "encrypted"	: NVDIMM contents are encrypted.

		* "smart_notify": There is health event for the NVDIMM.

		* "scrubbed"	: Indicating that contents of the

				  NVDIMM have been scrubbed.

		* "locked"	: Indicating that NVDIMM contents cant

				  be modified until next power cycle.

arch/powerpc/platforms/pseries/papr_scm.c

+166 −2
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/libnvdimm.h>

#include <linux/platform_device.h>

#include <linux/delay.h>

#include <linux/seq_buf.h>



#include <asm/plpar_wrappers.h>
@@ -22,6 +23,44 @@ 
	 (1ul << ND_CMD_GET_CONFIG_DATA) | \

	 (1ul << ND_CMD_SET_CONFIG_DATA))



/* 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 +78,15 @@ 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 +192,61 @@ static int drc_pmem_query_n_bind(struct papr_scm_priv *p) 
	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)
@@ -286,6 +389,64 @@ 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 +473,8 @@ 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 +560,9 @@ 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);