[PATCH 1/5] EDAC/skx_common: Enable EDAC support for the "near" memory

[Qiuxu Zhuo]

The current {skx,i10nm}_edac miss the EDAC support to decode errors from
the 1st level memory (the fast "near" memory as cache) of the 2-level
memory system. Introduce a helper function skx_error_in_mem() to check
whether errors are from memory at the beginning of skx_mce_check_error().

As long as the errors are from memory (either the 1-level memory system
or the 2-level memory system), decode the errors.

Reported-and-tested-by: Youquan Song <youquan.song@xxxxxxxxx>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
---
 drivers/edac/skx_common.c | 18 ++++++++++++------
 drivers/edac/skx_common.h | 24 ++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/edac/skx_common.c b/drivers/edac/skx_common.c
index f0f8e98f6efb..5fdcb6d5b96b 100644
--- a/drivers/edac/skx_common.c
+++ b/drivers/edac/skx_common.c
@@ -632,12 +632,18 @@ static bool skx_error_in_1st_level_mem(const struct mce *m)
 	if (!skx_mem_cfg_2lm)
 		return false;
 
-	errcode = GET_BITFIELD(m->status, 0, 15);
+	errcode = GET_BITFIELD(m->status, 0, 15) & MCACOD_MEM_ERR_MASK;
 
-	if ((errcode & 0xef80) != 0x280)
-		return false;
+	return errcode == MCACOD_EXT_MEM_ERR;
+}
 
-	return true;
+static bool skx_error_in_mem(const struct mce *m)
+{
+	u32 errcode;
+
+	errcode = GET_BITFIELD(m->status, 0, 15) & MCACOD_MEM_ERR_MASK;
+
+	return (errcode == MCACOD_MEM_CTL_ERR || errcode == MCACOD_EXT_MEM_ERR);
 }
 
 int skx_mce_check_error(struct notifier_block *nb, unsigned long val,
@@ -651,8 +657,8 @@ int skx_mce_check_error(struct notifier_block *nb, unsigned long val,
 	if (mce->kflags & MCE_HANDLED_CEC)
 		return NOTIFY_DONE;
 
-	/* ignore unless this is memory related with an address */
-	if ((mce->status & 0xefff) >> 7 != 1 || !(mce->status & MCI_STATUS_ADDRV))
+	/* Ignore unless this is memory related with an address */
+	if (!skx_error_in_mem(mce) || !(mce->status & MCI_STATUS_ADDRV))
 		return NOTIFY_DONE;
 
 	memset(&res, 0, sizeof(res));
diff --git a/drivers/edac/skx_common.h b/drivers/edac/skx_common.h
index 0cbadd3d2cd3..312032657264 100644
--- a/drivers/edac/skx_common.h
+++ b/drivers/edac/skx_common.h
@@ -56,6 +56,30 @@
 #define MCI_MISC_ECC_MODE(m)	(((m) >> 59) & 15)
 #define MCI_MISC_ECC_DDRT	8	/* read from DDRT */
 
+/*
+ * According to Intel Architecture spec vol 3B,
+ * Table 15-10 "IA32_MCi_Status [15:0] Compound Error Code Encoding"
+ * memory errors should fit one of these masks:
+ *	000f 0000 1mmm cccc (binary)
+ *	000f 0010 1mmm cccc (binary)	[RAM used as cache]
+ * where:
+ *	f = Correction Report Filtering Bit. If 1, subsequent errors
+ *	    won't be shown
+ *	mmm = error type
+ *	cccc = channel
+ */
+#define MCACOD_MEM_ERR_MASK	0xef80
+/*
+ * Errors from either the memory of the 1-level memory system or the
+ * 2nd level memory (the slow "far" memory) of the 2-level memory system.
+ */
+#define MCACOD_MEM_CTL_ERR	0x80
+/*
+ * Errors from the 1st level memory (the fast "near" memory as cache)
+ * of the 2-level memory system.
+ */
+#define MCACOD_EXT_MEM_ERR	0x280
+
 /*
  * Each cpu socket contains some pci devices that provide global
  * information, and also some that are local to each of the two
-- 
2.17.1