[PATCH v2] EDAC, ghes: use CPER module handles to locate DIMMs

For platforms whose firmwares provide valid module handles
(SMBIOS type 17) in error records, this patch uses the module
handles to locate corresponding DIMMs and enables per-DIMM
error counter update.

Signed-off-by: Fan Wu <redacted>
---

Changes from v1:
*  Changed the new function name to get_dimm_smbios_index
*  Removed unnecessary checks inside get_dimm_smbios_index
*  Reverted the change of the DMI handle print
*  Updated commit message

---
 drivers/edac/ghes_edac.c | 25 +++++++++++++++++++++++++
 include/linux/edac.h     |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 473aeec..949f603 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c

@@ -81,6 +81,20 @@ static void ghes_edac_count_dimms(const struct dmi_header *dh, void *arg)
 		(*num_dimm)++;
 }
 
+static int get_dimm_smbios_index(u16 handle)
+{
+	struct mem_ctl_info *mci;
+	int i;
+
+	mci = ghes_pvt->mci;
+
+	for (i = 0; i < mci->tot_dimms; i++) {
+		if (mci->dimms[i]->smbios_handle == handle)
+			return i;
+	}
+	return -1;
+}
+
 static void ghes_edac_dmidecode(const struct dmi_header *dh, void *arg)
 {
 	struct ghes_edac_dimm_fill *dimm_fill = arg;

@@ -177,6 +191,8 @@ static void ghes_edac_dmidecode(const struct dmi_header *dh, void *arg)
 				entry->total_width, entry->data_width);
 		}
 
+		dimm->smbios_handle = entry->handle;
+
 		dimm_fill->count++;
 	}
 }

@@ -327,12 +343,21 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err)
 		p += sprintf(p, "bit_pos:%d ", mem_err->bit_pos);
 	if (mem_err->validation_bits & CPER_MEM_VALID_MODULE_HANDLE) {
 		const char *bank = NULL, *device = NULL;
+		int index = -1;
+
 		dmi_memdev_name(mem_err->mem_dev_handle, &bank, &device);
 		if (bank != NULL && device != NULL)
 			p += sprintf(p, "DIMM location:%s %s ", bank, device);
 		else
 			p += sprintf(p, "DIMM DMI handle: 0x%.4x ",
 				     mem_err->mem_dev_handle);
+
+		index = get_dimm_smbios_index(mem_err->mem_dev_handle);
+		if (index >= 0) {
+			e->top_layer = index;
+			e->enable_per_layer_report = true;
+		}
+
 	}
 	if (p > e->location)
 		*(p - 1) = '\0';

diff --git a/include/linux/edac.h b/include/linux/edac.h
index bffb978..a45ce1f 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h

@@ -451,6 +451,8 @@ struct dimm_info {
 	u32 nr_pages;			/* number of pages on this dimm */
 
 	unsigned csrow, cschannel;	/* Points to the old API data */
+
+	u16 smbios_handle;              /* Handle for SMBIOS type 17 */
 };
 
 /**

-- 
2.7.4

Hi Fan,

On Thu, Aug 30, 2018 at 2:37 PM, Fan Wu [off-list ref] wrote:

For platforms whose firmwares provide valid module handles
(SMBIOS type 17) in error records, this patch uses the module
handles to locate corresponding DIMMs and enables per-DIMM
error counter update.

Signed-off-by: Fan Wu <redacted>

Minor nit: you could define and set mci in the same line to save some
space here.

Otherwise this patch looks good to me.

Reviewed-by: Tyler Baicar <redacted>

Hi Tyler, 

quoted

+static int get_dimm_smbios_index(u16 handle) {
+       struct mem_ctl_info *mci;
+       int i;
+
+       mci = ghes_pvt->mci;
+

Minor nit: you could define and set mci in the same line to save some space
here.

Otherwise this patch looks good to me.

Good catch Tyler! I'll fix it.

Thanks,
Fan

Reviewed-by: Tyler Baicar <redacted>

On Thu, 2018-08-30 at 18:37 +0000, Fan Wu wrote:

For platforms whose firmwares provide valid module handles
(SMBIOS type 17) in error records, this patch uses the module
handles to locate corresponding DIMMs and enables per-DIMM
error counter update.

Signed-off-by: Fan Wu <redacted>

Tested on an HPE x86 server. It turns out that mem_err->mem_dev_handle
was set to  0 with this FW, and get_dimm_smbios_index() returned -1. But
the code handles this case fine. dimm->smbios_handle's were initialized
properly. So:

Tested-by: Toshi Kani <redacted>

Thanks,
-Toshi