Date:   Wed, 30 Nov 2022 16:27:10 -0800
From:   ira.weiny@...el.com
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Ben Widawsky <bwidawsk@...nel.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Dave Jiang <dave.jiang@...el.com>,
        linux-kernel@...r.kernel.org, linux-cxl@...r.kernel.org
Subject: [PATCH V2 02/11] cxl/mem: Implement Get Event Records command

From: Ira Weiny <ira.weiny@...el.com>

CXL devices have multiple event logs which can be queried for CXL event
records.  Devices are required to support the storage of at least one
event record in each event log type.

Devices track event log overflow by incrementing a counter and tracking
the time of the first and last overflow event seen.

Software queries events via the Get Event Record mailbox command; CXL
rev 3.0 section 8.2.9.2.2.

Issue the Get Event Record mailbox command on driver load.  Trace each
record found with a generic record trace.  Trace any overflow
conditions.

The device can return up to 1MB worth of event records per query.
Allocate a shared large buffer to handle the max number of records based
on the mailbox payload size.

This patch traces a raw event record only and leaves the specific event
record types to subsequent patches.

Macros are created to use for tracing the common CXL Event header
fields.

Cc: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>

---
Change from V1:
	Ignore useless More Event Flag
	defer DCD support
	Jonathan
		delete extra blank line
		Use all caps for flags
	Jonathan/Dan/Ira
		Allocate event MB buffer on start up.
	Alison
		s/pl_nr/nr_pl

Change from RFC v2:
	Support reading 3 events at once.
	Reverse Jonathan's suggestion and check for positive number of
		records.  Because the record count may have been
		returned as something > 3 based on what the device
		thinks it can send back even though the core Linux mbox
		processing truncates the data.
	Alison and Dave Jiang
		Change header uuid type to uuid_t for better user space
		processing
	Smita
		Check status reg before reading log.
	Steven
		Prefix all trace points with 'cxl_'
		Use static branch <trace>_enabled() calls
	Jonathan
		s/CXL_EVENT_TYPE_INFO/0
		s/{first,last}/{first,last}_ts
		Remove Reserved field from header
		Fix header issue for cxl_event_log_type_str()

Change from RFC:
	Remove redundant error message in get event records loop
	s/EVENT_RECORD_DATA_LENGTH/CXL_EVENT_RECORD_DATA_LENGTH
	Use hdr_uuid for the header UUID field
	Use cxl_event_log_type_str() for the trace events
	Create macros for the header fields and common entries of each event
	Add reserved buffer output dump
	Report error if event query fails
	Remove unused record_cnt variable
	Steven - reorder overflow record
		Remove NOTE about checkpatch
	Jonathan
		check for exactly 1 record
		s/v3.0/rev 3.0
		Use 3 byte fields for 24bit fields
		Add 3.0 Maintenance Operation Class
		Add Dynamic Capacity log type
		Fix spelling
	Dave Jiang/Dan/Alison
		s/cxl-event/cxl
		trace/events/cxl-events => trace/events/cxl.h
		s/cxl_event_overflow/overflow
		s/cxl_event/generic_event
---
 MAINTAINERS                  |   1 +
 drivers/cxl/core/mbox.c      | 105 +++++++++++++++++++++++++++++
 drivers/cxl/cxl.h            |   7 ++
 drivers/cxl/cxlmem.h         |  72 ++++++++++++++++++++
 include/trace/events/cxl.h   | 126 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/cxl_mem.h |   1 +
 6 files changed, 312 insertions(+)
 create mode 100644 include/trace/events/cxl.h

diff --git a/MAINTAINERS b/MAINTAINERS
index ca063a504026..4b7c6e3055c6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5223,6 +5223,7 @@ M:	Dan Williams <dan.j.williams@...el.com>
 L:	linux-cxl@...r.kernel.org
 S:	Maintained
 F:	drivers/cxl/
+F:	include/trace/events/cxl.h
 F:	include/uapi/linux/cxl_mem.h
 
 CONEXANT ACCESSRUNNER USB DRIVER
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 16176b9278b4..70b681027a3d 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -7,6 +7,9 @@
 #include <cxlmem.h>
 #include <cxl.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/cxl.h>
+
 #include "core.h"
 
 static bool cxl_raw_allow_all;
@@ -48,6 +51,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
 	CXL_CMD(RAW, CXL_VARIABLE_PAYLOAD, CXL_VARIABLE_PAYLOAD, 0),
 #endif
 	CXL_CMD(GET_SUPPORTED_LOGS, 0, CXL_VARIABLE_PAYLOAD, CXL_CMD_FLAG_FORCE_ENABLE),
+	CXL_CMD(GET_EVENT_RECORD, 1, CXL_VARIABLE_PAYLOAD, 0),
 	CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
 	CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
 	CXL_CMD(GET_LSA, 0x8, CXL_VARIABLE_PAYLOAD, 0),
@@ -704,6 +708,106 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);
 
+static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
+				    enum cxl_event_log_type type)
+{
+	struct cxl_get_event_payload *payload;
+	u16 nr_rec;
+
+	mutex_lock(&cxlds->event_buf_lock);
+
+	payload = cxlds->event_buf;
+
+	do {
+		u8 log_type = type;
+		int rc;
+
+		rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_GET_EVENT_RECORD,
+				       &log_type, sizeof(log_type),
+				       payload, cxlds->payload_size);
+		if (rc) {
+			dev_err(cxlds->dev, "Event log '%s': Failed to query event records : %d",
+				cxl_event_log_type_str(type), rc);
+			goto unlock_buffer;
+		}
+
+		nr_rec = le16_to_cpu(payload->record_count);
+		if (trace_cxl_generic_event_enabled()) {
+			int i;
+
+			for (i = 0; i < nr_rec; i++)
+				trace_cxl_generic_event(dev_name(cxlds->dev),
+							type,
+							&payload->records[i]);
+		}
+
+		if (trace_cxl_overflow_enabled() &&
+		    (payload->flags & CXL_GET_EVENT_FLAG_OVERFLOW))
+			trace_cxl_overflow(dev_name(cxlds->dev), type, payload);
+
+	} while (nr_rec);
+
+unlock_buffer:
+	mutex_unlock(&cxlds->event_buf_lock);
+}
+
+static void cxl_mem_free_event_buffer(void *data)
+{
+	struct cxl_dev_state *cxlds = data;
+
+	kvfree(cxlds->event_buf);
+}
+
+/*
+ * There is a single buffer for reading event logs from the mailbox.  All logs
+ * share this buffer protected by the cxlds->event_buf_lock.
+ */
+static struct cxl_get_event_payload *alloc_event_buf(struct cxl_dev_state *cxlds)
+{
+	struct cxl_get_event_payload *buf;
+
+	dev_dbg(cxlds->dev, "Allocating event buffer size %zu\n",
+		cxlds->payload_size);
+
+	buf = kvmalloc(cxlds->payload_size, GFP_KERNEL);
+	if (buf && devm_add_action_or_reset(cxlds->dev,
+			cxl_mem_free_event_buffer, cxlds))
+		return NULL;
+	return buf;
+}
+
+/**
+ * cxl_mem_get_event_records - Get Event Records from the device
+ * @cxlds: The device data for the operation
+ *
+ * Retrieve all event records available on the device and report them as trace
+ * events.
+ *
+ * See CXL rev 3.0 @8.2.9.2.2 Get Event Records
+ */
+void cxl_mem_get_event_records(struct cxl_dev_state *cxlds)
+{
+	u32 status = readl(cxlds->regs.status + CXLDEV_DEV_EVENT_STATUS_OFFSET);
+
+	dev_dbg(cxlds->dev, "Reading event logs: %x\n", status);
+
+	if (!cxlds->event_buf) {
+		cxlds->event_buf = alloc_event_buf(cxlds);
+		if (WARN_ON_ONCE(!cxlds->event_buf))
+			return;
+	}
+
+	if (status & CXLDEV_EVENT_STATUS_INFO)
+		cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_INFO);
+	if (status & CXLDEV_EVENT_STATUS_WARN)
+		cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_WARN);
+	if (status & CXLDEV_EVENT_STATUS_FAIL)
+		cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_FAIL);
+	if (status & CXLDEV_EVENT_STATUS_FATAL)
+		cxl_mem_get_records_log(cxlds, CXL_EVENT_TYPE_FATAL);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_mem_get_event_records, CXL);
+
 /**
  * cxl_mem_get_partition_info - Get partition info
  * @cxlds: The device data for the operation
@@ -846,6 +950,7 @@ struct cxl_dev_state *cxl_dev_state_create(struct device *dev)
 	}
 
 	mutex_init(&cxlds->mbox_mutex);
+	mutex_init(&cxlds->event_buf_lock);
 	cxlds->dev = dev;
 
 	return cxlds;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index f680450f0b16..d4baae74cd97 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -132,6 +132,13 @@ static inline int ways_to_cxl(unsigned int ways, u8 *iw)
 #define CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX 0x3
 #define CXLDEV_CAP_CAP_ID_MEMDEV 0x4000
 
+/* CXL 3.0 8.2.8.3.1 Event Status Register */
+#define CXLDEV_DEV_EVENT_STATUS_OFFSET		0x00
+#define CXLDEV_EVENT_STATUS_INFO		BIT(0)
+#define CXLDEV_EVENT_STATUS_WARN		BIT(1)
+#define CXLDEV_EVENT_STATUS_FAIL		BIT(2)
+#define CXLDEV_EVENT_STATUS_FATAL		BIT(3)
+
 /* CXL 2.0 8.2.8.4 Mailbox Registers */
 #define CXLDEV_MBOX_CAPS_OFFSET 0x00
 #define   CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK GENMASK(4, 0)
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index cd35f43fedd4..55d57f5a64bc 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -4,6 +4,7 @@
 #define __CXL_MEM_H__
 #include <uapi/linux/cxl_mem.h>
 #include <linux/cdev.h>
+#include <linux/uuid.h>
 #include "cxl.h"
 
 /* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
@@ -250,12 +251,16 @@ struct cxl_dev_state {
 
 	bool msi_enabled;
 
+	struct cxl_get_event_payload *event_buf;
+	struct mutex event_buf_lock;
+
 	int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd);
 };
 
 enum cxl_opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
+	CXL_MBOX_OP_GET_EVENT_RECORD	= 0x0100,
 	CXL_MBOX_OP_GET_FW_INFO		= 0x0200,
 	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
 	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
@@ -325,6 +330,72 @@ struct cxl_mbox_identify {
 	u8 qos_telemetry_caps;
 } __packed;
 
+/*
+ * Common Event Record Format
+ * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
+ */
+struct cxl_event_record_hdr {
+	uuid_t id;
+	u8 length;
+	u8 flags[3];
+	__le16 handle;
+	__le16 related_handle;
+	__le64 timestamp;
+	u8 maint_op_class;
+	u8 reserved[0xf];
+} __packed;
+
+#define CXL_EVENT_RECORD_DATA_LENGTH 0x50
+struct cxl_event_record_raw {
+	struct cxl_event_record_hdr hdr;
+	u8 data[CXL_EVENT_RECORD_DATA_LENGTH];
+} __packed;
+
+/*
+ * Get Event Records output payload
+ * CXL rev 3.0 section 8.2.9.2.2; Table 8-50
+ */
+#define CXL_GET_EVENT_FLAG_OVERFLOW		BIT(0)
+#define CXL_GET_EVENT_FLAG_MORE_RECORDS		BIT(1)
+struct cxl_get_event_payload {
+	u8 flags;
+	u8 reserved1;
+	__le16 overflow_err_count;
+	__le64 first_overflow_timestamp;
+	__le64 last_overflow_timestamp;
+	__le16 record_count;
+	u8 reserved2[0xa];
+	struct cxl_event_record_raw records[];
+} __packed;
+
+/*
+ * CXL rev 3.0 section 8.2.9.2.2; Table 8-49
+ */
+enum cxl_event_log_type {
+	CXL_EVENT_TYPE_INFO = 0x00,
+	CXL_EVENT_TYPE_WARN,
+	CXL_EVENT_TYPE_FAIL,
+	CXL_EVENT_TYPE_FATAL,
+	CXL_EVENT_TYPE_MAX
+};
+
+static inline const char *cxl_event_log_type_str(enum cxl_event_log_type type)
+{
+	switch (type) {
+	case CXL_EVENT_TYPE_INFO:
+		return "Informational";
+	case CXL_EVENT_TYPE_WARN:
+		return "Warning";
+	case CXL_EVENT_TYPE_FAIL:
+		return "Failure";
+	case CXL_EVENT_TYPE_FATAL:
+		return "Fatal";
+	default:
+		break;
+	}
+	return "<unknown>";
+}
+
 struct cxl_mbox_get_partition_info {
 	__le64 active_volatile_cap;
 	__le64 active_persistent_cap;
@@ -384,6 +455,7 @@ int cxl_mem_create_range_info(struct cxl_dev_state *cxlds);
 struct cxl_dev_state *cxl_dev_state_create(struct device *dev);
 void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
 void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
+void cxl_mem_get_event_records(struct cxl_dev_state *cxlds);
 #ifdef CONFIG_CXL_SUSPEND
 void cxl_mem_active_inc(void);
 void cxl_mem_active_dec(void);
diff --git a/include/trace/events/cxl.h b/include/trace/events/cxl.h
new file mode 100644
index 000000000000..c03a1a894af8
--- /dev/null
+++ b/include/trace/events/cxl.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cxl
+
+#if !defined(_CXL_TRACE_EVENTS_H) ||  defined(TRACE_HEADER_MULTI_READ)
+#define _CXL_TRACE_EVENTS_H
+
+#include <asm-generic/unaligned.h>
+#include <linux/tracepoint.h>
+#include <cxlmem.h>
+
+TRACE_EVENT(cxl_overflow,
+
+	TP_PROTO(const char *dev_name, enum cxl_event_log_type log,
+		 struct cxl_get_event_payload *payload),
+
+	TP_ARGS(dev_name, log, payload),
+
+	TP_STRUCT__entry(
+		__string(dev_name, dev_name)
+		__field(int, log)
+		__field(u64, first_ts)
+		__field(u64, last_ts)
+		__field(u16, count)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev_name, dev_name);
+		__entry->log = log;
+		__entry->count = le16_to_cpu(payload->overflow_err_count);
+		__entry->first_ts = le64_to_cpu(payload->first_overflow_timestamp);
+		__entry->last_ts = le64_to_cpu(payload->last_overflow_timestamp);
+	),
+
+	TP_printk("%s: EVENT LOG OVERFLOW log=%s : %u records from %llu to %llu",
+		__get_str(dev_name), cxl_event_log_type_str(__entry->log),
+		__entry->count, __entry->first_ts, __entry->last_ts)
+
+);
+
+/*
+ * Common Event Record Format
+ * CXL 3.0 section 8.2.9.2.1; Table 8-42
+ */
+#define CXL_EVENT_RECORD_FLAG_PERMANENT		BIT(2)
+#define CXL_EVENT_RECORD_FLAG_MAINT_NEEDED	BIT(3)
+#define CXL_EVENT_RECORD_FLAG_PERF_DEGRADED	BIT(4)
+#define CXL_EVENT_RECORD_FLAG_HW_REPLACE	BIT(5)
+#define show_hdr_flags(flags)	__print_flags(flags, " | ",			   \
+	{ CXL_EVENT_RECORD_FLAG_PERMANENT,	"PERMANENT_CONDITION"		}, \
+	{ CXL_EVENT_RECORD_FLAG_MAINT_NEEDED,	"MAINTENANCE_NEEDED"		}, \
+	{ CXL_EVENT_RECORD_FLAG_PERF_DEGRADED,	"PERFORMANCE_DEGRADED"		}, \
+	{ CXL_EVENT_RECORD_FLAG_HW_REPLACE,	"HARDWARE_REPLACEMENT_NEEDED"	}  \
+)
+
+/*
+ * Define macros for the common header of each CXL event.
+ *
+ * Tracepoints using these macros must do 3 things:
+ *
+ *	1) Add CXL_EVT_TP_entry to TP_STRUCT__entry
+ *	2) Use CXL_EVT_TP_fast_assign within TP_fast_assign;
+ *	   pass the dev_name, log, and CXL event header
+ *	3) Use CXL_EVT_TP_printk() instead of TP_printk()
+ *
+ * See the generic_event tracepoint as an example.
+ */
+#define CXL_EVT_TP_entry					\
+	__string(dev_name, dev_name)				\
+	__field(int, log)					\
+	__field_struct(uuid_t, hdr_uuid)			\
+	__field(u32, hdr_flags)					\
+	__field(u16, hdr_handle)				\
+	__field(u16, hdr_related_handle)			\
+	__field(u64, hdr_timestamp)				\
+	__field(u8, hdr_length)					\
+	__field(u8, hdr_maint_op_class)
+
+#define CXL_EVT_TP_fast_assign(dname, l, hdr)					\
+	__assign_str(dev_name, (dname));					\
+	__entry->log = (l);							\
+	memcpy(&__entry->hdr_uuid, &(hdr).id, sizeof(uuid_t));			\
+	__entry->hdr_length = (hdr).length;					\
+	__entry->hdr_flags = get_unaligned_le24((hdr).flags);			\
+	__entry->hdr_handle = le16_to_cpu((hdr).handle);			\
+	__entry->hdr_related_handle = le16_to_cpu((hdr).related_handle);	\
+	__entry->hdr_timestamp = le64_to_cpu((hdr).timestamp);			\
+	__entry->hdr_maint_op_class = (hdr).maint_op_class
+
+#define CXL_EVT_TP_printk(fmt, ...) \
+	TP_printk("%s log=%s : time=%llu uuid=%pUb len=%d flags='%s' "		\
+		"handle=%x related_handle=%x maint_op_class=%u"			\
+		" : " fmt,							\
+		__get_str(dev_name), cxl_event_log_type_str(__entry->log),	\
+		__entry->hdr_timestamp, &__entry->hdr_uuid, __entry->hdr_length,\
+		show_hdr_flags(__entry->hdr_flags), __entry->hdr_handle,	\
+		__entry->hdr_related_handle, __entry->hdr_maint_op_class,	\
+		##__VA_ARGS__)
+
+TRACE_EVENT(cxl_generic_event,
+
+	TP_PROTO(const char *dev_name, enum cxl_event_log_type log,
+		 struct cxl_event_record_raw *rec),
+
+	TP_ARGS(dev_name, log, rec),
+
+	TP_STRUCT__entry(
+		CXL_EVT_TP_entry
+		__array(u8, data, CXL_EVENT_RECORD_DATA_LENGTH)
+	),
+
+	TP_fast_assign(
+		CXL_EVT_TP_fast_assign(dev_name, log, rec->hdr);
+		memcpy(__entry->data, &rec->data, CXL_EVENT_RECORD_DATA_LENGTH);
+	),
+
+	CXL_EVT_TP_printk("%s",
+		__print_hex(__entry->data, CXL_EVENT_RECORD_DATA_LENGTH))
+);
+
+#endif /* _CXL_TRACE_EVENTS_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE cxl
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index c71021a2a9ed..70459be5bdd4 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -24,6 +24,7 @@
 	___C(IDENTIFY, "Identify Command"),                               \
 	___C(RAW, "Raw device command"),                                  \
 	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
+	___C(GET_EVENT_RECORD, "Get Event Record"),                       \
 	___C(GET_FW_INFO, "Get FW Info"),                                 \
 	___C(GET_PARTITION_INFO, "Get Partition Information"),            \
 	___C(GET_LSA, "Get Label Storage Area"),                          \
-- 
2.37.2

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