Re: [EDAC ABI v13 04/25] events/hw_event: Create a Hardware EventsReport Mecanism (HERM)

[Mauro Carvalho Chehab]

Em 09-05-2012 11:19, Steven Rostedt escreveu:
> On Wed, 2012-05-09 at 10:51 -0300, Mauro Carvalho Chehab wrote:
>> Em 09-05-2012 10:22, Borislav Petkov escreveu:
>>> + Tony.
>>
>> C/C Steven.
> 
> Hehe, I was already Cc'd ;-)

:)

>> One other option would be to call it as "include/trace/events/ras.h".
>>
>> Steven,
>>
>> Would it be possible/recommendable to move this trace header
>> to include/linux/ras/hw_event.h?
> 
> Yeah, it's not hard. In fact, it's documented in
> samples/trace_events/trace-events-sample.h:
> 
> /*
>  * There are several ways I could have done this. If I left out the
>  * TRACE_INCLUDE_PATH, then it would default to the kernel source
>  * include/trace/events directory.
>  *
>  * I could specify a path from the define_trace.h file back to this
>  * file.
>  *
>  * #define TRACE_INCLUDE_PATH ../../samples/trace_events
>  *
>  * But the safest and easiest way to simply make it use the directory
>  * that the file is in is to add in the Makefile:
>  *
>  * CFLAGS_trace-events-sample.o := -I$(src)
>  *
>  * This will make sure the current path is part of the include
>  * structure for our file so that define_trace.h can find it.
>  *
>  * I could have made only the top level directory the include:
>  *
>  * CFLAGS_trace-events-sample.o := -I$(PWD)
>  *
>  * And then let the path to this directory be the TRACE_INCLUDE_PATH:
>  *
>  * #define TRACE_INCLUDE_PATH samples/trace_events
>  *
>  * But then if something defines "samples" or "trace_events" as a macro
>  * then we could risk that being converted too, and give us an unexpected
>  * result.
>  */
> 
> But usually the header would go where the code is:
> 
> drivers/edac/hw_event.h
> 
> Or rename it. The XFS tracepoints do this:
> 
> fs/xfs/xfs_trace.h

As the idea is to use it on other RAS facilities, it is better to put it
at include/ras/hw_event.h

PS.: putting it at include/linux/ras/hw_event.h doesn't work, as "linux"
is evaluated to "1" at TRACE_INCLUDE_PATH macro.

Anyway, patch is enclosed.

Regards,
Mauro.

-

edac, ras/hw_event.h: use HERM events to handle hw issues

From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>

Add a new tracepoint-based Hardware Events Report Method (HERM) for
outputing Memory Controller events.

Part of the description bellow is shamelessly copied from Tony
Luck's notes about the Hardware Error BoF during LPC 2010 [1].
Tony, thanks for your notes and discussions to generate the
h/w error reporting requirements.

[1] http://lwn.net/Articles/416669/

    We have several subsystems & methods for reporting hardware errors:

    1) EDAC ("Error Detection and Correction").  In its original form
    this consisted of a platform specific driver that read topology
    information and error counts from chipset registers and reported
    the results via a sysfs interface.

    2) mcelog - x86 specific decoding of machine check bank registers
    reporting in binary form via /dev/mcelog. Recent additions make use
    of the APEI extensions that were documented in version 4.0a of the
    ACPI specification to acquire more information about errors without
    having to rely reading chipset registers directly. A user level
    programs decodes into somewhat human readable format.

    3) drivers/edac/mce_amd.c - this driver hooks into the mcelog path and
    decodes errors reported via machine check bank registers in AMD
    processors to the console log using printk();

    Each of these mechanisms has a band of followers ... and none
    of them appear to meet all the needs of all users.

As part of a hardware event subsystem, let's encapsulate the memory
error hardware events into a trace facility.

NOTE: The original patch was providing an additional mechanism for
MCA-based trace events that also contained MCA error register data.
Hoever, as no agreement was reached so far for the MCA-based trace
events, for now, let's add events only for memory errors.
A latter patch is planned to change the tracepoint, for those types
of event.

Reviewed-by: Aristeu Rozanski <arozansk@xxxxxxxxxx>
Cc: Doug Thompson <norsk5@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>

diff --git a/drivers/edac/edac_core.h b/drivers/edac/edac_core.h
index f06ce9a..eee7360 100644
--- a/drivers/edac/edac_core.h
+++ b/drivers/edac/edac_core.h
@@ -468,7 +468,7 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
 			  const int layer2,
 			  const char *msg,
 			  const char *other_detail,
-			  const void *mcelog);
+			  const void *arch_log);
 
 /*
  * edac_device APIs
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index e5b5563..11f0178 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -33,6 +33,10 @@
 #include "edac_core.h"
 #include "edac_module.h"
 
+#define CREATE_TRACE_POINTS
+#define TRACE_INCLUDE_PATH ../../include/ras
+#include <ras/hw_event.h>
+
 /* lock to memory controller's control array */
 static DEFINE_MUTEX(mem_ctls_mutex);
 static LIST_HEAD(mc_devices);
@@ -381,6 +385,7 @@ struct mem_ctl_info *edac_mc_alloc(unsigned mc_num,
 	 * which will perform kobj unregistration and the actual free
 	 * will occur during the kobject callback operation
 	 */
+
 	return mci;
 }
 EXPORT_SYMBOL_GPL(edac_mc_alloc);
@@ -982,7 +987,7 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
 			  const int layer2,
 			  const char *msg,
 			  const char *other_detail,
-			  const void *mcelog)
+			  const void *arch_log)
 {
 	/* FIXME: too much for stack: move it to some pre-alocated area */
 	char detail[80], location[80];
@@ -1119,21 +1124,27 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
 	}
 
 	/* Memory type dependent details about the error */
-	if (type == HW_EVENT_ERR_CORRECTED) {
+	if (type == HW_EVENT_ERR_CORRECTED)
 		snprintf(detail, sizeof(detail),
 			"page:0x%lx offset:0x%lx grain:%d syndrome:0x%lx",
 			page_frame_number, offset_in_page,
 			grain, syndrome);
-		edac_ce_error(mci, pos, msg, location, label, detail,
-			      other_detail, enable_per_layer_report,
-			      page_frame_number, offset_in_page, grain);
-	} else {
+	else
 		snprintf(detail, sizeof(detail),
 			"page:0x%lx offset:0x%lx grain:%d",
 			page_frame_number, offset_in_page, grain);
 
+	/* Report the error via the trace interface */
+	trace_mc_error(type, mci->mc_idx, msg, label, location,
+		       detail, other_detail);
+
+	/* Report the error via the edac_mc_printk() interface */
+	if (type == HW_EVENT_ERR_CORRECTED)
+		edac_ce_error(mci, pos, msg, location, label, detail,
+			      other_detail, enable_per_layer_report,
+			      page_frame_number, offset_in_page, grain);
+	else
 		edac_ue_error(mci, pos, msg, location, label, detail,
 			      other_detail, enable_per_layer_report);
-	}
 }
 EXPORT_SYMBOL_GPL(edac_mc_handle_error);
diff --git a/include/ras/hw_event.h b/include/ras/hw_event.h
new file mode 100644
index 0000000..fe2ec3b
--- /dev/null
+++ b/include/ras/hw_event.h
@@ -0,0 +1,77 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hw_event
+
+#if !defined(_TRACE_HW_EVENT_MC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HW_EVENT_MC_H
+
+#include <linux/tracepoint.h>
+#include <linux/edac.h>
+#include <linux/ktime.h>
+
+/*
+ * Hardware Events Report Method (HERM)
+ *
+ * Those events are generated when hardware detected a corrected or
+ * uncorrected event, and are meant to replace the current API to report
+ * errors defined on both EDAC and MCE subsystems.
+ *
+ * FIXME: Add events for handling memory errors originated from the
+ *        MCE subsystem.
+ */
+
+/*
+ * Hardware-independent Memory Controller specific events
+ */
+
+/*
+ * Default error mechanisms for Memory Controller errors (CE and UE)
+ */
+TRACE_EVENT(mc_error,
+
+	TP_PROTO(const unsigned int err_type,
+		 const unsigned int mc_index,
+		 const char *msg,
+		 const char *label,
+		 const char *location,
+		 const char *detail,
+		 const char *driver_detail),
+
+	TP_ARGS(err_type, mc_index, msg, label, location,
+		detail, driver_detail),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	err_type		)
+		__field(	unsigned int,	mc_index		)
+		__string(	msg,		msg			)
+		__string(	label,		label			)
+		__string(	detail,		detail			)
+		__string(	location,	location		)
+		__string(	driver_detail,	driver_detail		)
+	),
+
+	TP_fast_assign(
+		__entry->err_type		= err_type;
+		__entry->mc_index		= mc_index;
+		__assign_str(msg, msg);
+		__assign_str(label, label);
+		__assign_str(location, location);
+		__assign_str(detail, detail);
+		__assign_str(driver_detail, driver_detail);
+	),
+
+	TP_printk(HW_ERR "mce#%d: %s error %s on memory stick \"%s\" (%s %s %s)",
+		  __entry->mc_index,
+		  (__entry->err_type == HW_EVENT_ERR_CORRECTED) ? "Corrected" :
+			((__entry->err_type == HW_EVENT_ERR_FATAL) ?
+			"Fatal" : "Uncorrected"),
+		  __get_str(msg),
+		  __get_str(label),
+		  __get_str(location),
+		  __get_str(detail),
+		  __get_str(driver_detail))
+);
+
+#endif /* _TRACE_HW_EVENT_MC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>



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