The MCE severity judgement code is data-driven, so code coverage tools
such as gcov can not be used for measuring coverage. Instead a dedicated
coverage mechanism is implemented.  The kernel keeps track of rules
executed and reports them in debugfs.

This is useful for increasing coverage of the mce-test testsuite.

Right now it's unconditionally enabled because it's very little code.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The x86 architecture recently added some new machine check status bits:
S(ignalled) and AR (Action-Required). Signalled allows to check
if a specific event caused an exception or was just logged through CMCI.
AR allows the kernel to decide if an event needs immediate action
or can be delayed or ignored.

Implement support for these new status bits. mce_severity() uses
the new bits to grade the machine check correctly and decide what
to do. The exception handler uses AR to decide to kill or not.
The S bit is used to separate events between the poll/CMCI handler
and the exception handler.

Classical UC always leads to panic. That was true before anyways
because the existing CPUs always passed a PCC with it.

Also corrects the rules whether to kill in user or kernel context
and how to handle missing RIPV.

The machine check handler largely uses the mce-severity grading
engine now instead of making its own decisions. This means the logic
is centralized in one place.  This is useful because it has to be
evaluated multiple times.

v2: Some rule fixes; Add AO events
Fix RIPV, RIPV|EIPV order (Ying Huang)
Fix UCNA with AR=1 message (Ying Huang)
Add comment about panicing in m_c_p.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

When multiple MCEs are printed print the "HARDWARE ERROR" header
and "This is not a software error" footer only once. This
makes the output much more compact with many CPUs.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fatal machine checks can be logged to disk after boot, but only if
the system did a warm reboot. That's unfortunately difficult with the
default panic behaviour, which waits forever and the admin has to
press the power button because modern systems usually miss a reset button.
This clears the machine checks in the registers and make
it impossible to log them.

This patch changes the default for machine check panic to always
reboot after 30s. Then the mce can be successfully logged after
reboot.

I believe this will improve machine check experience for any
system running the X server.

This is dependent on successfull boot logging of MCEs. This currently
only works on Intel systems, on AMD there are quite a lot of systems
around which leave junk in the machine check registers after boot,
so it's disabled here. These systems will continue to default
to endless waiting panic.

v2: Only force panic timeout when it's shorter (H.Seto)
v3: Only force timeout when there is no timeout
(based on comment H.Seto)

[ Fix changelog - HS ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Assume IP on the stack is valid when either EIPV or RIPV are set.
This influences whether the machine check exception handler decides
to return or panic.

This fixes a test case in the mce-test suite and is more compliant
to the specification.

This currently only makes a difference in a artificial testing
scenario with the mce-test test suite.

Also in addition do not force the EIPV to be valid with the exact
register MSRs, and keep in trust the CS value on stack even if MSR
is available.

[AK: combination of patches from Huang Ying and Hidetoshi Seto, with
new description by me]
[add some description, no code changed - HS]
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

... instead of "Machine check". This is for consistency with the Monarch
panic message.

Based on a report from Ying Huang.

v2: But add a descriptive postfix so that the test suite can distingush.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

On Intel platforms machine check exceptions are always broadcast to
all CPUs.  This patch makes the machine check handler synchronize all
these machine checks, elect a Monarch to handle the event and collect
the worst event from all CPUs and then process it first.

This has some advantages:

- When there is a truly data corrupting error the system panics as
  quickly as possible. This improves containment of corrupted
  data and makes sure the corrupted data never hits stable storage.

- The panics are synchronized and do not reenter the panic code
  on multiple CPUs (which currently does not handle this well).

- All the errors are reported. Currently it often happens that
  another CPU happens to do the panic first, but reports useless
  information (empty machine check) because the real error
  happened on another CPU which came in later.
  This is a big advantage on Nehalem where the 8 threads per CPU
  lead to often the wrong CPU winning the race and dumping
  useless information on a machine check.  The problem also occurs
  in a less severe form on older CPUs.

- The system can detect when no CPUs detected a machine check
  and shut down the system.  This can happen when one CPU is so
  badly hung that that it cannot process a machine check anymore
  or when some external agent wants to stop the system by
  asserting the machine check pin.  This follows Intel hardware
  recommendations.

- This matches the recommended error model by the CPU designers.

- The events can be output in true severity order

- When a panic happens on another CPU it makes sure to be actually
  be able to process the stop IPI by enabling interrupts.

The code is extremly careful to handle timeouts while waiting
for other CPUs. It can't rely on the normal timing mechanisms
(jiffies, ktime_get) because of its asynchronous/lockless nature,
so it uses own timeouts using ndelay() and a "SPINUNIT"

The timeout is configurable. By default it waits for upto one
second for the other CPUs.  This can be also disabled.

From some informal testing AMD systems do not see to broadcast
machine checks, so right now it's always disabled by default on
non Intel CPUs or also on very old Intel systems.

Includes fixes from Ying Huang
Fixed a "ecception" in a comment (H.Seto)
Moved global_nwo reset later based on suggestion from H.Seto
v2: Avoid duplicate messages

[ Impact: feature, fixes long standing problems. ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In some circumstances multiple CPUs can enter mce_panic() in parallel.
This gives quite confused output because they will all dump the same
machine check buffer.

The other problem is that they would all panic in parallel, but not
process each other's shutdown IPIs because interrupts are disabled.

Detect this situation early on in mce_panic(). On the first CPU
entering will do the panic, the others will just wait to be killed.

For paranoia reasons in case the other CPU dies during the MCE I added
a 5 seconds timeout. If it expires each CPU will panic on its own again.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Machine checks support waking up the mcelog daemon quickly.

The original wake up code for this was pretty ugly, relying on
a idle notifier and a special process flag. The reason it did
it this way is that the machine check handler is not subject
to normal interrupt locking rules so it's not safe
to call wake_up().  Instead it set a process flag
and then either did the wakeup in the syscall return
or in the idle notifier.

This patch adds a new "bootstraping" method as replacement.

The idea is that the handler checks if it's in a state where
it is unsafe to call wake_up(). If it's safe it calls it directly.
When it's not safe -- that is it interrupted in a critical
section with interrupts disables -- it uses a new "self IPI" to trigger
an IPI to its own CPU. This can be done safely because IPI
triggers are atomic with some care. The IPI is raised
once the interrupts are reenabled and can then safely call
wake_up().

When APICs are disabled the event is just queued and will be picked up
eventually by the next polling timer. I think that's a reasonable
compromise, since it should only happen quite rarely.

Contains fixes from Ying Huang.

[ solve conflict on irqinit, make it work on 32bit (entry_arch.h) - HS ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The exception handler should behave differently if the exception is
fatal versus one that can be returned from.  In the first case it should
never clear any registers because these need to be preserved
for logging after the next boot. Otherwise it should clear them
on each CPU step by step so that other CPUs sharing the same bank don't
see duplicate events. Otherwise we risk reporting events multiple
times on any CPUs which have shared machine check banks, which
is a common problem on Intel Nehalem which has both SMT (two
CPU threads sharing banks) and shared machine check banks in the uncore.

Determine early in a special pass if any event requires a panic.
This uses the mce_severity() function added earlier.

This is needed for the next patch.

Also fixes a problem together with an earlier patch
that corrected events weren't logged on a fatal MCE.

[ Impact: Feature ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The machine check grading (as in deciding what should be done for a given
register value) has to be done multiple times soon and it's also getting
more complicated.
So it makes sense to consolidate it into a single function. To get smaller
and more straight forward and possibly more extensible code I opted towards
a new table driven method. The various rules are put into a table
when is then executed by a very simple interpreter.

The grading engine is in a new file mce-severity.c. I also added a private
include file mce-internal.h, because mce.h is already a bit too cluttered.

This is dead code right now, but will be used in followon patches.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Previously mce_panic used a simple heuristic to avoid printing
old so far unreported machine check events on a mce panic. This worked
by comparing the TSC value at the start of the machine check handler
with the event time stamp and only printing newer ones.

This has a couple of issues, in particular on systems where the TSC
is not fully synchronized between CPUs it could lose events or print
old ones.

It is also problematic with full system synchronization as it is
added by the next patch.

Remove the TSC heuristic and instead replace it with a simple heuristic
to print corrected errors first and after that uncorrected errors
and finally the worst machine check as determined by the machine
check handler.

This simplifies the code because there is no need to pass the
original TSC value around.

Contains fixes from Ying Huang

[ Impact: bug fix, cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Ying Huang <ying.huang@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Normally the machine check handler ignores corrected errors and leaves
them to machine_check_poll(). But when panicing mcp won't run, so
log all errors.

Note: this can still miss some cases until the "early no way out"
patch later is applied too.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Experience has shown that struct mce which is used to pass an machine
check to the user space daemon currently a few limitations.  Also some
data which is useful to print at panic level is also missing.

This patch addresses most of them. The same information is also
printed out together with mce panic.

struct mce can be painlessly extended in a compatible way, the mcelog
user space code just ignores additional fields with a warning.

- It doesn't provide a wall time timestamp. There have been a few
  complaints about that. Fix that by adding a 64bit time_t

- It doesn't provide the exact CPU identification. This makes
  it awkward for mcelog to decode the event correctly, especially
  when there are variations in the supported MCE codes on different
  CPU models or when mcelog is running on a different host after a panic.
  Previously the administrator had to specify the correct CPU
  when mcelog ran on a different host, but with the more variation
  in machine checks now it's better to auto detect that.
  It's also useful for more detailed analysis of CPU events.
  Pass CPUID 1.EAX and the cpu vendor (as encoded in processor.h) instead.

- Socket ID and initial APIC ID are useful to report because they
  allow to identify the failing CPU in some (not all) cases.
  This is also especially useful for the panic situation.
  This addresses one of the complaints from Thomas Gleixner earlier.

- The MCG capabilities MSR needs to be reported for some advanced
  error processing in mcelog
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The old struct mce had a limitation to 256 CPUs. But x86 Linux supports
more than that now with x2apic. Add a new field extcpu to report the
extended number.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This makes it easier for tools who want to extract the mcelog out of
crash images or memory dumps to adapt to changing struct mce size.
The length field replaces padding, so it's fully compatible.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Keep a count of the machine check polls (or CMCI events) in
/proc/interrupts.

Andi needs this for debugging, but it's also useful in general
to see what's going in by the kernel.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Useful for debugging, but it's also good general policy
to have a counter for all special interrupts there. This makes it easier
to diagnose where a CPU is spending its time.

[ Impact: feature, debugging tool ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13302

On x86 and x86-64, it is possible that page tables are shared beween
shared mappings backed by hugetlbfs.  As part of this,
page_table_shareable() checks a pair of vma->vm_flags and they must match
if they are to be shared.  All VMA flags are taken into account, including
VM_LOCKED.

The problem is that VM_LOCKED is cleared on fork().  When a process with a
shared memory segment forks() to exec() a helper, there will be shared
VMAs with different flags.  The impact is that the shared segment is
sometimes considered shareable and other times not, depending on what
process is checking.

What happens is that the segment page tables are being shared but the
count is inaccurate depending on the ordering of events.  As the page
tables are freed with put_page(), bad pmd's are found when some of the
children exit.  The hugepage counters also get corrupted and the Total and
Free count will no longer match even when all the hugepage-backed regions
are freed.  This requires a reboot of the machine to "fix".

This patch addresses the problem by comparing all flags except VM_LOCKED
when deciding if pagetables should be shared or not for hugetlbfs-backed
mapping.
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <starlight@binnacle.cx>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Function prototypes don't need to be prefixed by "extern".

[ Impact: cleanup ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Use tab.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fix a wrong comment.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fix for:

WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
+#include <asm/uaccess.h>

WARNING: usage of NR_CPUS is often wrong - consider using cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc
+       if (m.cpu >= NR_CPUS || !cpu_online(m.cpu))

ERROR: trailing whitespace
+/* $
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fix for:

WARNING: space prohibited between function name and open parenthesis '('
+       for_each_online_cpu (cpu) {
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fix for followings:

WARNING: Use #include <linux/percpu.h> instead of <asm/percpu.h>
+#include <asm/percpu.h>

ERROR: Macros with multiple statements should be enclosed in a do - while
loop
+#define THRESHOLD_ATTR(_name, _mode, _show, _store)                    \
+{                                                                      \
+       .attr   = {.name = __stringify(_name), .mode = _mode },         \
+       .show   = _show,                                                \
+       .store  = _store,                                               \
+};

WARNING: usage of NR_CPUS is often wrong - consider using cpu_possible(),
num_possible_cpus(), for_each_possible_cpu(), etc
+       if (cpu >= NR_CPUS)
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This fixs following checkpatch warnings:

WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
+#include <asm/uaccess.h>

WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>
+#include <asm/smp.h>

WARNING: line over 80 characters
+                               set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog.flags);

WARNING: braces {} are not necessary for any arm of this statement
+       if (mce_notify_user()) {
[...]
+       } else {
[...]
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This patch removes following checkpatch warning:

WARNING: Use #include <linux/cpu.h> instead of <asm/cpu.h>
+#include <asm/cpu.h>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Use strict_strtoull instead of simple_strtoull.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

BKL is not needed for anything in mce_open because it has
an own spinlock. Remove it.

[ Impact: cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

There's only a single out path in do_machine_check now, so rename the
label from out2 to out.  Also align it at the first column.

[ Impact: minor cleanup, no functional changes ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Remove unused mce_init argument.

[ Impact: cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Remove unused mce_events static variable.

[ Impact: cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Instead of using own callbacks use the generic ones provided by
the sysdev later.

This finally allows to get rid of the ugly ACCESSOR macros. Should
also save some text size.

[ Impact: cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The example code in the IA32 SDM recommends to synchronize the CPU
after machine check handling. So do that here.

[ Impact: Spec compliance ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Fix style of winged comment in mce-inject.c.

[ Impact: comment only ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Add a comment explaining that mce_chrdev_ops is intentionally
writable.

[ Impact: comment only ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Allow user programs to write mce records into /dev/mcelog. When they do
that a fake machine check is triggered to test the machine check code.

This uses the MCE MSR wrappers added earlier.

The implementation is straight forward. There is a struct mce record
per CPU and the MCE MSR accesses get data from there if there is valid
data injected there. This allows to test the machine check code
relatively realistically because only the lowest layer of hardware
access is intercepted.

The test suite and injector are available at
git://git.kernel.org/pub/scm/utils/cpu/mce/mce-test.git
git://git.kernel.org/pub/scm/utils/cpu/mce/mce-inject.gitSigned-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This will be used by future patches to allow machine check error injection.
Right now it's a nop, except for adding some wrappers around the MSR reads.

This is early in the sequence to avoid too many conflicts.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

That's very easy using the infrastructure enabled earlier for MCE_INTEL

Untested.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>