x86, mce, severity: Extend the the mce_severity mechanism to handle UCNA/DEFERRED error

Until now, the mce_severity mechanism can only identify the severity
of UCNA error as MCE_KEEP_SEVERITY. Meanwhile, it is not able to filter
out DEFERRED error for AMD platform.

This patch extends the mce_severity mechanism for handling
UCNA/DEFERRED error. In order to do this, the patch introduces a new
severity level - MCE_UCNA/DEFERRED_SEVERITY.

In addition, mce_severity is specific to machine check exception,
and it will check MCIP/EIPV/RIPV bits. In order to use mce_severity
mechanism in non-exception context, the patch also introduces a new
argument (is_excp) for mce_severity. `is_excp' is used to explicitly
specify the calling context of mce_severity.

Reviewed-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Chen Yucong <slaoub@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 276392f..51b26e89 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -34,6 +34,10 @@
 #define MCI_STATUS_S	 (1ULL<<56)  /* Signaled machine check */
 #define MCI_STATUS_AR	 (1ULL<<55)  /* Action required */
 
+/* AMD-specific bits */
+#define MCI_STATUS_DEFERRED	(1ULL<<44)  /* declare an uncorrected error */
+#define MCI_STATUS_POISON	(1ULL<<43)  /* access poisonous data */
+
 /*
  * 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