Message-Id: <20200615124407.32596-7-vaibhav@linux.ibm.com>
Date:   Mon, 15 Jun 2020 18:14:07 +0530
From:   Vaibhav Jain <vaibhav@...ux.ibm.com>
To:     linuxppc-dev@...ts.ozlabs.org, linux-nvdimm@...ts.01.org,
        linux-kernel@...r.kernel.org
Cc:     Vaibhav Jain <vaibhav@...ux.ibm.com>,
        Dan Williams <dan.j.williams@...el.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        "Oliver O'Halloran" <oohall@...il.com>,
        Santosh Sivaraj <santosh@...six.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ira Weiny <ira.weiny@...el.com>
Subject: [PATCH v13 6/6] powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH

This patch implements support for PDSM request 'PAPR_PDSM_HEALTH'
that returns a newly introduced 'struct nd_papr_pdsm_health' instance
containing dimm health information back to user space in response to
ND_CMD_CALL. This functionality is implemented in newly introduced
papr_pdsm_health() that queries the nvdimm health information and
then copies this information to the package payload whose layout is
defined by 'struct nd_papr_pdsm_health'.

Cc: "Aneesh Kumar K . V" <aneesh.kumar@...ux.ibm.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Vaibhav Jain <vaibhav@...ux.ibm.com>
---
Changelog:
v12..v13:
* Added the 'struct nd_papr_pdsm_health' to 'union nd_pdsm_payload'
* Added pdsm descriptor of 'PAPR_PDSM_HEALTH' to
  __pdsm_cmd_descriptors[].
* Updated papr_pdsm_health() to copy the dimm health information
  directly into PDSM payload rather then copying it to an intermediate
  struct and then memcpy it to the PDSM payload area.

v11..v12:
* Minor: Reodered the initialization of 'struct nd_papr_pdsm_health'
  fields to match order present in its definition. [ Ira ]
* Added ack from Ira

v10..v11:
* Changed the definition of 'struct nd_papr_pdsm_health' to a maximal
  struct 184 bytes in size [ Dan Williams ]
* Added new field 'extension_flags' to 'struct nd_papr_pdsm_health'
  [ Dan Williams ]
* Updated papr_pdsm_health() to set field 'extension_flags' to 0.
* Introduced a define ND_PDSM_PAYLOAD_MAX_SIZE that indicates the
  maximum size of a payload.
* Fixed a suspicious conversion from u64 to u8 in papr_pdsm_health
  that was preventing correct initialization of 'struct
  nd_papr_pdsm_health'. [ Ira ]

v9..v10:
* Removed code in papr_pdsm_health that performed validation on pdsm
  payload version and corrosponding struct and defines used for
  validation of payload version.
* Dropped usage of struct papr_pdsm_health in 'struct
  papr_scm_priv'. Instead papr_psdm_health() now uses
  'papr_scm_priv.health_bitmap' to populate the pdsm payload.
* Above change also fixes the problem where this patch was removing
  the code that was previously introduced in this patch-series.
  [ Ira ]
* Introduced a new def ND_PDSM_ENVELOPE_HDR_SIZE that indicates the
  space allocated to 'struct nd_pdsm_cmd_pkg' fields except 'struct
  nd_cmd_pkg'. This def is useful in validating payload sizes.
* Reworked papr_pdsm_health() to enforce a specific payload size for
  'PAPR_PDSM_HEALTH' pdsm request.

Resend:
* Added ack from Aneesh.

v8..v9:
* s/PAPR_SCM_PDSM_HEALTH/PAPR_PDSM_HEALTH/g  [ Dan , Aneesh ]
* s/PAPR_SCM_PSDM_DIMM_*/PAPR_PDSM_DIMM_*/g
* Renamed papr_scm_get_health() to papr_psdm_health()
* Updated patch description to replace papr-scm dimm with nvdimm.

v7..v8:
* None

Resend:
* None

v6..v7:
* Updated flags_show() to use seq_buf_printf(). [Mpe]
* Updated papr_scm_get_health() to use newly introduced
  __drc_pmem_query_health() bypassing the cache [Mpe].

v5..v6:
* Added attribute '__packed' to 'struct nd_papr_pdsm_health_v1' to
  gaurd against possibility of different compilers adding different
  paddings to the struct [ Dan Williams ]

* Updated 'struct nd_papr_pdsm_health_v1' to use __u8 instead of
  'bool' and also updated drc_pmem_query_health() to take this into
  account. [ Dan Williams ]

v4..v5:
* None

v3..v4:
* Call the DSM_PAPR_SCM_HEALTH service function from
  papr_scm_service_dsm() instead of papr_scm_ndctl(). [Aneesh]

v2..v3:
* Updated struct nd_papr_scm_dimm_health_stat_v1 to use '__xx' types
  as its exported to the userspace [Aneesh]
* Changed the constants DSM_PAPR_SCM_DIMM_XX indicating dimm health
  from enum to #defines [Aneesh]

v1..v2:
* New patch in the series
---
 arch/powerpc/include/uapi/asm/papr_pdsm.h | 37 ++++++++++++++++
 arch/powerpc/platforms/pseries/papr_scm.c | 51 +++++++++++++++++++++++
 2 files changed, 88 insertions(+)

diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h b/arch/powerpc/include/uapi/asm/papr_pdsm.h
index 28115152aa4e..9ccecc1d6840 100644
--- a/arch/powerpc/include/uapi/asm/papr_pdsm.h
+++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
@@ -66,17 +66,54 @@
 #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;
 
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index d3bbf9940ba4..9c569078a09f 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -416,6 +416,52 @@ static int is_cmd_valid(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
 	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
@@ -444,6 +490,11 @@ static const struct pdsm_cmd_desc __pdsm_cmd_descriptors[] = {
 	},
 	/* 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,
-- 
2.26.2

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