tracing: Add the ::microcode field to the mce_record tracepoint

Currently, the microcode field (Microcode Revision) of 'struct mce' is not
exposed to userspace through the mce_record tracepoint.

Knowing the microcode version on which the MCE was received is critical
information for debugging. If the version is not recorded, later attempts
to acquire the version might result in discrepancies since it can be
changed at runtime.

Add microcode version to the tracepoint to prevent ambiguity over
the active version on the system when the MCE was received.

Signed-off-by: Avadhut Naik <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Sohil Mehta <[email protected]>
Reviewed-by: Steven Rostedt (Google) <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Avadhut Naik

include/trace/events/mce.h

@@ -42,6 +42,7 @@ TRACE_EVENT(mce_record,
 		__field(	u8,		cs		)
 		__field(	u8,		bank		)
 		__field(	u8,		cpuvendor	)
+		__field(	u32,		microcode	)
 	),
 
 	TP_fast_assign(
@@ -63,9 +64,10 @@ TRACE_EVENT(mce_record,
 		__entry->cs		= m->cs;
 		__entry->bank		= m->bank;
 		__entry->cpuvendor	= m->cpuvendor;
+		__entry->microcode	= m->microcode;
 	),
 
-	TP_printk("CPU: %d, MCGc/s: %llx/%llx, MC%d: %016Lx, IPID: %016Lx, ADDR: %016Lx, MISC: %016Lx, SYND: %016Lx, RIP: %02x:<%016Lx>, TSC: %llx, PPIN: %llx, vendor: %u, CPUID: %x, time: %llu, socket: %u, APIC: %x",
+	TP_printk("CPU: %d, MCGc/s: %llx/%llx, MC%d: %016Lx, IPID: %016Lx, ADDR: %016Lx, MISC: %016Lx, SYND: %016Lx, RIP: %02x:<%016Lx>, TSC: %llx, PPIN: %llx, vendor: %u, CPUID: %x, time: %llu, socket: %u, APIC: %x, microcode: %x",
 		__entry->cpu,
 		__entry->mcgcap, __entry->mcgstatus,
 		__entry->bank, __entry->status,
@@ -80,7 +82,8 @@ TRACE_EVENT(mce_record,
 		__entry->cpuid,
 		__entry->walltime,
 		__entry->socketid,
-		__entry->apicid)
+		__entry->apicid,
+		__entry->microcode)
 );
 
 #endif /* _TRACE_MCE_H */