EDAC/mce_amd: Decode MCA_STATUS[Scrub] bit

Previous AMD systems have had a bit in MCA_STATUS to indicate that an
error was detected on a scrub operation. However, this bit was defined
differently within different banks and families/models.

Starting with Family 17h, MCA_STATUS[40] is either Reserved/Read-as-Zero
or defined as "Scrub", for all MCA banks and CPU models. Therefore, this
bit can be defined as the "Scrub" bit.

Define MCA_STATUS[40] as "Scrub" and decode it in the AMD MCE decoding
module for Family 17h and newer systems.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190212212417.107049-1-Yazen.Ghannam@amd.com

arch/x86/include/asm/mce.h

@@ -48,6 +48,7 @@
 #define MCI_STATUS_SYNDV	BIT_ULL(53)  /* synd reg. valid */
 #define MCI_STATUS_DEFERRED	BIT_ULL(44)  /* uncorrected error, deferred exception */
 #define MCI_STATUS_POISON	BIT_ULL(43)  /* access poisonous data */
+#define MCI_STATUS_SCRUB	BIT_ULL(40)  /* Error detected during scrub operation */
 
 /*
  * McaX field if set indicates a given bank supports MCA extensions:

drivers/edac/mce_amd.c

@@ -1078,6 +1078,9 @@ amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
 	if (ecc)
 		pr_cont("|%sECC", ((ecc == 2) ? "C" : "U"));
 
+	if (fam >= 0x17)
+		pr_cont("|%s", (m->status & MCI_STATUS_SCRUB ? "Scrub" : "-"));
+
 	pr_cont("]: 0x%016llx\n", m->status);
 
 	if (m->status & MCI_STATUS_ADDRV)