[PATCH 4/6] cxl/events: Create a CXL event union

[Ira Weiny]

The CXL CPER and event log records share everything but a UUID/GUID in
their structures.

Define a cxl_event union without the UUID/GUID to be shared between the
CPER and event log record formats.  Adjust the code to use this union.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

---
Changes from RFC:
[iweiny: ensure event union is packed]
---
 drivers/cxl/core/mbox.c      | 32 +++++++++++++-------------------
 drivers/cxl/core/trace.h     |  8 ++++----
 include/linux/cxl-event.h    | 23 +++++++++++++++++------
 tools/testing/cxl/test/mem.c | 31 ++++++++++++++++++-------------
 4 files changed, 52 insertions(+), 42 deletions(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 9ad8cbfca952..5ccc3843b736 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -864,26 +864,17 @@ static void cxl_event_trace_record(const struct cxl_memdev *cxlmd,
 				   enum cxl_event_log_type type,
 				   struct cxl_event_record_raw *record)
 {
+	union cxl_event *evt = &record->event;
 	uuid_t *id = &record->id;
 
-	if (uuid_equal(id, &gen_media_event_uuid)) {
-		struct cxl_event_gen_media *rec =
-				(struct cxl_event_gen_media *)record;
-
-		trace_cxl_general_media(cxlmd, type, id, rec);
-	} else if (uuid_equal(id, &dram_event_uuid)) {
-		struct cxl_event_dram *rec = (struct cxl_event_dram *)record;
-
-		trace_cxl_dram(cxlmd, type, id, rec);
-	} else if (uuid_equal(id, &mem_mod_event_uuid)) {
-		struct cxl_event_mem_module *rec =
-				(struct cxl_event_mem_module *)record;
-
-		trace_cxl_memory_module(cxlmd, type, id, rec);
-	} else {
-		/* For unknown record types print just the header */
-		trace_cxl_generic_event(cxlmd, type, id, record);
-	}
+	if (uuid_equal(id, &gen_media_event_uuid))
+		trace_cxl_general_media(cxlmd, type, id, &evt->gen_media);
+	else if (uuid_equal(id, &dram_event_uuid))
+		trace_cxl_dram(cxlmd, type, id, &evt->dram);
+	else if (uuid_equal(id, &mem_mod_event_uuid))
+		trace_cxl_memory_module(cxlmd, type, id, &evt->mem_module);
+	else
+		trace_cxl_generic_event(cxlmd, type, id, &evt->generic);
 }
 
 static int cxl_clear_event_record(struct cxl_memdev_state *mds,
@@ -926,7 +917,10 @@ static int cxl_clear_event_record(struct cxl_memdev_state *mds,
 	 */
 	i = 0;
 	for (cnt = 0; cnt < total; cnt++) {
-		payload->handles[i++] = get_pl->records[cnt].hdr.handle;
+		struct cxl_event_record_raw *raw = &get_pl->records[cnt];
+		struct cxl_event_generic *gen = &raw->event.generic;
+
+		payload->handles[i++] = gen->hdr.handle;
 		dev_dbg(mds->cxlds.dev, "Event log '%d': Clearing %u\n", log,
 			le16_to_cpu(payload->handles[i]));
 
diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
index 2aef185f4cd0..3d007f0472f2 100644
--- a/drivers/cxl/core/trace.h
+++ b/drivers/cxl/core/trace.h
@@ -225,9 +225,9 @@ TRACE_EVENT(cxl_overflow,
 TRACE_EVENT(cxl_generic_event,
 
 	TP_PROTO(const struct cxl_memdev *cxlmd, enum cxl_event_log_type log,
-		 const uuid_t *uuid, struct cxl_event_record_raw *rec),
+		 const uuid_t *uuid, struct cxl_event_generic *gen_rec),
 
-	TP_ARGS(cxlmd, log, uuid, rec),
+	TP_ARGS(cxlmd, log, uuid, gen_rec),
 
 	TP_STRUCT__entry(
 		CXL_EVT_TP_entry
@@ -235,8 +235,8 @@ TRACE_EVENT(cxl_generic_event,
 	),
 
 	TP_fast_assign(
-		CXL_EVT_TP_fast_assign(cxlmd, log, uuid, rec->hdr);
-		memcpy(__entry->data, &rec->data, CXL_EVENT_RECORD_DATA_LENGTH);
+		CXL_EVT_TP_fast_assign(cxlmd, log, uuid, gen_rec->hdr);
+		memcpy(__entry->data, gen_rec->data, CXL_EVENT_RECORD_DATA_LENGTH);
 	),
 
 	CXL_EVT_TP_printk("%s",
diff --git a/include/linux/cxl-event.h b/include/linux/cxl-event.h
index ebb00ead1496..18dab4d90dc8 100644
--- a/include/linux/cxl-event.h
+++ b/include/linux/cxl-event.h
@@ -18,13 +18,8 @@ struct cxl_event_record_hdr {
 	u8 reserved[15];
 } __packed;
 
-/*
- * Common Event Record Format
- * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
- */
 #define CXL_EVENT_RECORD_DATA_LENGTH 0x50
-struct cxl_event_record_raw {
-	uuid_t id;
+struct cxl_event_generic {
 	struct cxl_event_record_hdr hdr;
 	u8 data[CXL_EVENT_RECORD_DATA_LENGTH];
 } __packed;
@@ -97,4 +92,20 @@ struct cxl_event_mem_module {
 	u8 reserved[0x3d];
 } __packed;
 
+union cxl_event {
+	struct cxl_event_generic generic;
+	struct cxl_event_gen_media gen_media;
+	struct cxl_event_dram dram;
+	struct cxl_event_mem_module mem_module;
+} __packed;
+
+/*
+ * Common Event Record Format; in event logs
+ * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
+ */
+struct cxl_event_record_raw {
+	uuid_t id;
+	union cxl_event event;
+} __packed;
+
 #endif /* _LINUX_CXL_EVENT_H */
diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
index e7113edfbfa5..39681372484a 100644
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -251,7 +251,8 @@ static int mock_get_event(struct device *dev, struct cxl_mbox_cmd *cmd)
 	for (i = 0; i < CXL_TEST_EVENT_CNT && !event_log_empty(log); i++) {
 		memcpy(&pl->records[i], event_get_current(log),
 		       sizeof(pl->records[i]));
-		pl->records[i].hdr.handle = event_get_cur_event_handle(log);
+		pl->records[i].event.generic.hdr.handle =
+				event_get_cur_event_handle(log);
 		log->cur_idx++;
 	}
 
@@ -339,25 +340,29 @@ static void cxl_mock_event_trigger(struct device *dev)
 struct cxl_event_record_raw maint_needed = {
 	.id = UUID_INIT(0xBA5EBA11, 0xABCD, 0xEFEB,
 			0xa5, 0x5a, 0xa5, 0x5a, 0xa5, 0xa5, 0x5a, 0xa5),
-	.hdr = {
-		.length = sizeof(struct cxl_event_record_raw),
-		.flags[0] = CXL_EVENT_RECORD_FLAG_MAINT_NEEDED,
-		/* .handle = Set dynamically */
-		.related_handle = cpu_to_le16(0xa5b6),
+	.event.generic = {
+		.hdr = {
+			.length = sizeof(struct cxl_event_record_raw),
+			.flags[0] = CXL_EVENT_RECORD_FLAG_MAINT_NEEDED,
+			/* .handle = Set dynamically */
+			.related_handle = cpu_to_le16(0xa5b6),
+		},
+		.data = { 0xDE, 0xAD, 0xBE, 0xEF },
 	},
-	.data = { 0xDE, 0xAD, 0xBE, 0xEF },
 };
 
 struct cxl_event_record_raw hardware_replace = {
 	.id = UUID_INIT(0xABCDEFEB, 0xBA11, 0xBA5E,
 			0xa5, 0x5a, 0xa5, 0x5a, 0xa5, 0xa5, 0x5a, 0xa5),
-	.hdr = {
-		.length = sizeof(struct cxl_event_record_raw),
-		.flags[0] = CXL_EVENT_RECORD_FLAG_HW_REPLACE,
-		/* .handle = Set dynamically */
-		.related_handle = cpu_to_le16(0xb6a5),
+	.event.generic = {
+		.hdr = {
+			.length = sizeof(struct cxl_event_record_raw),
+			.flags[0] = CXL_EVENT_RECORD_FLAG_HW_REPLACE,
+			/* .handle = Set dynamically */
+			.related_handle = cpu_to_le16(0xb6a5),
+		},
+		.data = { 0xDE, 0xAD, 0xBE, 0xEF },
 	},
-	.data = { 0xDE, 0xAD, 0xBE, 0xEF },
 };
 
 struct cxl_test_gen_media {

-- 
2.42.0