x86/mce: Pay no attention to 'F' bit in MCACOD when parsing 'UC' errors

commit 0ca06c0857aee11911f91621db14498496f2c2cd upstream.

The 0x1000 bit of the MCACOD field of machine check MCi_STATUS
registers is only defined for corrected errors (where it means
that hardware may be filtering errors see SDM section 15.9.2.1).

For uncorrected errors it may, or may not be set - so we should mask
it out when checking for the architecturaly defined recoverable
error signatures (see SDM 15.9.3.1 and 15.9.3.2)

Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index fa5f71e..e6833c6 100644 (file)
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -32,11 +32,20 @@
 #define MCI_STATUS_PCC   (1ULL<<57)  /* processor context corrupt */
 #define MCI_STATUS_S    (1ULL<<56)  /* Signaled machine check */
 #define MCI_STATUS_AR   (1ULL<<55)  /* Action required */
-#define MCACOD           0xffff     /* MCA Error Code */
+
+/*
+ * Note that the full MCACOD field of IA32_MCi_STATUS MSR is
+ * bits 15:0.  But bit 12 is the 'F' bit, defined for corrected
+ * errors to indicate that errors are being filtered by hardware.
+ * We should mask out bit 12 when looking for specific signatures
+ * of uncorrected errors - so the F bit is deliberately skipped
+ * in this #define.
+ */
+#define MCACOD           0xefff     /* MCA Error Code */
 
 /* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
 #define MCACOD_SCRUB   0x00C0  /* 0xC0-0xCF Memory Scrubbing */
-#define MCACOD_SCRUBMSK        0xfff0
+#define MCACOD_SCRUBMSK        0xeff0  /* Skip bit 12 ('F' bit) */
 #define MCACOD_L3WB    0x017A  /* L3 Explicit Writeback */
 #define MCACOD_DATA    0x0134  /* Data Load */
 #define MCACOD_INSTR   0x0150  /* Instruction Fetch */