linux-kernel - [PATCH 07/11] EDAC/ghes: Have a separate code path for creating the fake MC

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Date:   Fri,  6 Mar 2020 16:13:14 +0100
From:   Robert Richter <rrichter@...vell.com>
To:     Borislav Petkov <bp@...en8.de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tony Luck <tony.luck@...el.com>
CC:     James Morse <james.morse@....com>,
        Aristeu Rozanski <aris@...hat.com>,
        Robert Richter <rrichter@...vell.com>,
        <linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 07/11] EDAC/ghes: Have a separate code path for creating the fake MC

The code in ghes_edac_register() switches back and forth between
standard and fake controller creation. Do one thing only and separate
the code path that creates the fake MC.

Note: For better review the code is not yet carved out in separate
functions.

Signed-off-by: Robert Richter <rrichter@...vell.com>
---
 drivers/edac/ghes_edac.c | 65 ++++++++++++++++++++++++----------------
 1 file changed, 40 insertions(+), 25 deletions(-)

diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 5a4c9694bbff..7ead5667ed73 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -535,7 +535,6 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	struct ghes_dimm_fill dimm_fill;
 	int rc = 0, num_dimm = 0;
 	struct mem_ctl_info *mci;
-	bool fake = false;
 	int idx;
 
 	if (IS_ENABLED(CONFIG_X86)) {
@@ -559,23 +558,42 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	/* Get the number of DIMMs */
 	dmi_walk(ghes_edac_count_dimms, &num_dimm);
 
-	/* Check if we've got a bogus BIOS */
-	if (num_dimm == 0) {
-		fake = true;
-		num_dimm = 1;
-	}
+	if (!num_dimm) {
+		/*
+		 * Bogus BIOS: Ignore DMI topology and use a single MC
+		 * with only one DIMM for the whole address range to
+		 * catch all errros.
+		 */
+		struct dimm_info *dimm;
 
-	mci = ghes_mc_create(dev, 0, num_dimm);
-	if (!mci) {
-		rc = -ENOMEM;
-		goto unlock;
-	}
+		mci = ghes_mc_create(dev, 0, 1);
+		if (!mci) {
+			rc = -ENOMEM;
+			goto unlock;
+		}
+
+		dimm = edac_get_dimm_by_index(mci, 0);
+
+		dimm->nr_pages = 1;
+		dimm->grain = 128;
+		dimm->mtype = MEM_UNKNOWN;
+		dimm->dtype = DEV_UNKNOWN;
+		dimm->edac_mode = EDAC_SECDED;
+
+		snprintf(dimm->label, sizeof(dimm->label), "unknown memory");
+
+		rc = ghes_mc_add_or_free(mci);
+		if (rc)
+			goto unlock;
 
-	if (fake) {
 		pr_info("This system has a very crappy BIOS: It doesn't even list the DIMMS.\n");
 		pr_info("Its SMBIOS info is wrong. It is doubtful that the error report would\n");
 		pr_info("work on such system. Use this driver with caution\n");
-	} else if (idx < 0) {
+
+		goto out;
+	}
+
+	if (idx < 0) {
 		pr_info("This EDAC driver relies on BIOS to enumerate memory and get error reports.\n");
 		pr_info("Unfortunately, not all BIOSes reflect the memory layout correctly.\n");
 		pr_info("So, the end result of using this driver varies from vendor to vendor.\n");
@@ -584,24 +602,21 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 		pr_info("This system has %d DIMM sockets.\n", num_dimm);
 	}
 
-	if (!fake) {
-		dimm_fill.index = 0;
-		dimm_fill.mci = mci;
-		dmi_walk(ghes_edac_dmidecode, &dimm_fill);
-	} else {
-		struct dimm_info *dimm = edac_get_dimm(mci, 0, 0, 0);
-
-		dimm->nr_pages = 1;
-		dimm->grain = 128;
-		dimm->mtype = MEM_UNKNOWN;
-		dimm->dtype = DEV_UNKNOWN;
-		dimm->edac_mode = EDAC_SECDED;
+	mci = ghes_mc_create(dev, 0, num_dimm);
+	if (!mci) {
+		rc = -ENOMEM;
+		goto unlock;
 	}
 
+	dimm_fill.index = 0;
+	dimm_fill.mci = mci;
+	dmi_walk(ghes_edac_dmidecode, &dimm_fill);
+
 	rc = ghes_mc_add_or_free(mci);
 	if (rc)
 		goto unlock;
 
+out:
 	/* only set on success */
 	refcount_set(&ghes_refcount, 1);
 
-- 
2.20.1