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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 58b278f568 ("powerpc: Provide initial documentation for
PAPR hcalls")

Signed-off-by: Vaibhav 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: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Vaibhav Jain 2020-06-15 18:14:04 +05:30 committed by Dan Williams
parent 97c02c723b
commit b791abf320
2 changed files with 193 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
Documentation/ABI/testing/sysfs-bus-papr-pmem Normal file
View File

@ -0,0 +1,27 @@
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.

168
arch/powerpc/platforms/pseries/papr_scm.c
View File

@ -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);