x86, intel: Output microcode revision in /proc/cpuinfo

I got a request to make it easier to determine the microcode
update level on Intel CPUs. This patch adds a new "microcode"
field to /proc/cpuinfo.

The microcode level is also outputed on fatal machine checks
together with the other CPUID model information.

I removed the respective code from the microcode update driver,
it just reads the field from cpu_data. Also when the microcode
is updated it fills in the new values too.

I had to add a memory barrier to native_cpuid to prevent it
being optimized away when the result is not used.

This turns out to clean up further code which already got this
information manually. This is done in followon patches.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1318466795-7393-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 08363b042122..8af6fa473233 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -217,8 +217,13 @@ static void print_mce(struct mce *m)
                 pr_cont("MISC %llx ", m->misc);
 
         pr_cont("\n");
-        pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n",
-                m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid);
+        /*
+         * Note this output is parsed by external tools and old fields
+         * should not be changed.
+         */
+        pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x microcode %u\n",
+                m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
+                cpu_data(m->extcpu).microcode);
 
         /*
          * Print out human-readable details about the MCE error,