ghes_edac: Fix RAS tracing

With the current version of CPER, there's no way to associate an
error with the memory error. So, the error location in EDAC
layers is unused.

As CPER has its own idea about memory architectural layers, just
output whatever is there inside the driver's detail at the RAS
tracepoint.

The EDAC location keeps untouched, in the case that, in some future,
we could actually map the error into the dimm labels.

Now, the error message:

[   72.396625] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 0
[   72.396627] {1}[Hardware Error]: APEI generic hardware error status
[   72.396628] {1}[Hardware Error]: severity: 2, corrected
[   72.396630] {1}[Hardware Error]: section: 0, severity: 2, corrected
[   72.396632] {1}[Hardware Error]: flags: 0x01
[   72.396634] {1}[Hardware Error]: primary
[   72.396635] {1}[Hardware Error]: section_type: memory error
[   72.396637] {1}[Hardware Error]: error_status: 0x0000000000000400
[   72.396638] {1}[Hardware Error]: node: 3
[   72.396639] {1}[Hardware Error]: card: 0
[   72.396640] {1}[Hardware Error]: module: 0
[   72.396641] {1}[Hardware Error]: device: 0
[   72.396643] {1}[Hardware Error]: error_type: 18, unknown
[   72.396666] EDAC MC0: 1 CE reserved error (18) on unknown label (node:3 card:0 module:0 page:0x0 offset:0x0 grain:0 syndrome:0x0 - status(0x0000000000000400): Storage error in DRAM memory)

Is properly represented on the trace event:

     kworker/0:2-584   [000] ....    72.396657: mc_event: 1 Corrected error: reserved error (18) on unknown label (mc:0 location:-1:-1:-1 address:0x00000000 grain:1 syndrome:0x00000000 APEI location: node:3 card:0 module:0 status(0x0000000000000400): Storage error in DRAM memory)

Tested on a 4 sockets E5-4650 Sandy Bridge machine.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/edac/ghes_edac.c

@@ -15,6 +15,7 @@
 #include <linux/edac.h>
 #include <linux/dmi.h>
 #include "edac_core.h"
+#include <ras/ras_event.h>
 
 #define GHES_EDAC_REVISION " Ver: 1.0.0"
 
@@ -24,6 +25,7 @@ struct ghes_edac_pvt {
 	struct mem_ctl_info *mci;
 
 	/* Buffers for the error handling routine */
+	char detail_location[240];
 	char other_detail[160];
 	char msg[80];
 };
@@ -191,6 +193,7 @@ void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
 	struct mem_ctl_info *mci;
 	struct ghes_edac_pvt *pvt = NULL;
 	char *p;
+	u8 grain_bits;
 
 	list_for_each_entry(pvt, &ghes_reglist, list) {
 		if (ghes == pvt->ghes)
@@ -398,6 +401,16 @@ void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
 	if (p > pvt->other_detail)
 		*(p - 1) = '\0';
 
+	/* Generate the trace event */
+	grain_bits = fls_long(e->grain);
+	sprintf(pvt->detail_location, "APEI location: %s %s",
+		e->location, e->other_detail);
+	trace_mc_event(type, e->msg, e->label, e->error_count,
+		       mci->mc_idx, e->top_layer, e->mid_layer, e->low_layer,
+		       PAGES_TO_MiB(e->page_frame_number) | e->offset_in_page,
+		       grain_bits, e->syndrome, pvt->detail_location);
+
+	/* Report the error via EDAC API */
 	edac_raw_mc_handle_error(type, mci, e);
 }
 EXPORT_SYMBOL_GPL(ghes_edac_report_mem_error);