Impact: reduce kernel memory usage when CONFIG_CPUMASK_OFFSTACK=y

Simple conversion of mce_device_initialized to cpumask_var_t.  We don't
check the alloc_cpumask_var() return since it's boot-time only, and
the misc_register() in that same function isn't checked.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Impact: saving power _very_ little

round_jiffies() round up absolute jiffies to full second.
round_jiffies_relative() round up relative jiffies to full second.

The "t->expires" is absolute jiffies. Then, round_jiffies() should be
used instead round_jiffies_relative().
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Major new feature

Intel CMCI (Corrected Machine Check Interrupt) is a new
feature on Nehalem CPUs. It allows the CPU to trigger
interrupts on corrected events, which allows faster
reaction to them instead of with the traditional
polling timer.

Also use CMCI to discover shared banks. Machine check banks
can be shared by CPU threads or even cores. Using the CMCI enable
bit it is possible to detect the fact that another CPU already
saw a specific bank. Use this to assign shared banks only
to one CPU to avoid reporting duplicated events.

On CPU hot unplug bank sharing is re discovered. This is done
using a thread that cycles through all the CPUs.

To avoid races between the poller and CMCI we only poll
for banks that are not CMCI capable and only check CMCI
owned banks on a interrupt.

The shared banks ownership information is currently only used for
CMCI interrupts, not polled banks.

The sharing discovery code follows the algorithm recommended in the
IA32 SDM Vol3a 14.5.2.1

The CMCI interrupt handler just calls the machine check poller to
pick up the machine check event that caused the interrupt.

I decided not to implement a separate threshold event like
the AMD version has, because the threshold is always one currently
and adding another event didn't seem to add any value.

Some code inspired by Yunhong Jiang's Xen implementation,
which was in term inspired by a earlier CMCI implementation
by me.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Define a per cpu bitmap that contains the banks polled by the machine
check poller. This is needed for the CMCI code in the next patches
to be able to disable polling on specific banks.

The bank by default contains all banks, so there is no behaviour
change. Only future code will remove some banks from the polling
set.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: behavior change, use common code

Use a standard leaky bucket ratelimit for the machine check
warning print interval instead of waiting every check_interval.
Also decrease the limit to twice per minute.
This interacts better with threshold interrupts because
they can happen more often than check_interval.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Cleanup (code movement)

Move MAX_NR_BANKS into mce.h because it's needed there
for followup patches.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Bug fix when CPU hotplug is disabled

Correct the following broken __cpuinit/__cpuexit annotations:

- mce_cpu_features() is called from mce_resume(), and so cannot be
  __cpuinit.
- mce_disable_cpu() and mce_reenable_cpu() are called from
  mce_cpu_callback(), and so cannot be __cpuexit().

Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: Bug fix on UP

Checkin 6ec68bff:
    x86, mce: reinitialize per cpu features on resume

introduced a call to mce_cpu_features() in the resume path, in order
for the MCE machinery to get properly reinitialized after a resume.
However, this function (and its successors) was flagged __cpuinit,
which becomes __init on UP configurations (on SMP suspend/resume
requires CPU hotplug and so this would not be seen.)

Remove the offending __cpuinit annotations for mce_cpu_features() and
its successor functions.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Cleanup

The standard spelling of a printf pattern for long long is "ll", not
"L", which is for long double.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup, performance enhancement

The machine check poller is diverging more and more from the fatal
exception handler. Instead of adding more special cases separate the code
paths completely. The corrected poll path is actually quite simple,
and this doesn't result in much code duplication.

This makes both handlers much easier to read and results in
cleaner code flow.  The exception handler now only needs to care
about uncorrected errors, which also simplifies the handling of multiple
errors. The corrected poller also now always runs in standard interrupt
context and does not need to do anything special to handle NMI context.

Minor behaviour changes:
- MCG status is now not cleared on polling.
- Only the banks which had corrected errors get cleared on polling
- The exception handler only clears banks with errors now

v2: Forward port to new patch order. Add "uc" argument.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup

This merely factors out duplicated code to set up
the initial struct mce state into a single function.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup; making code future proof; memory saving on small systems

This patch replaces the hardcoded max number of machine check banks with 
dynamic allocation depending on what the CPU reports. The sysfs
data structures and the banks array are dynamically allocated.

There is still a hard bank limit (128) because the mcelog protocol uses
banks >= 128 as pseudo banks to escape other events. But we expect
that 128 banks is beyond any reasonable CPU for now.

This supersedes an earlier patch by Venki, but it solves the problem
more completely by making the limit fully dynamic (up to the 128
boundary).

This saves some memory on machines with less than 6 banks because
they won't need sysdevs for unused ones and also allows to 
use sysfs to control these banks on possible future CPUs with
more than 6 banks.

This is an updated patch addressing Venki's comments.  I also added in
another patch from Thomas which fixed the error allocation path (that
patch was previously separated)

Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: bugfix

Considering the situation as follow:

before: mcelog.next == 1, mcelog.entry[0].finished = 1

+--------------------------------------------------------------------------
R                   W1                  W2                  W3

read mcelog.next (1)
                    mcelog.next++ (2)
                    (working on entry 1,
                    finished == 0)

mcelog.next = 0
                                        mcelog.next++ (1)
                                        (working on entry 0)
                                                           mcelog.next++ (2)
                                                           (working on entry 1)
                        <----------------- race ---------------->
                    (done on entry 1,
                    finished = 1)
                                                           (done on entry 1,
                                                           finished = 1)

To fix the race condition, a cmpxchg loop is added to mce_read() to
ensure no new MCE record can be added between mcelog.next reading and
mcelog.next = 0.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Lower priority bug fix

Offlined CPUs could still get machine checks, but the machine check handler
cannot handle them properly, leading to an unconditional crash. Disable
machine checks on CPUs that are going down.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: bug fix, in this case the resume handler shouldn't run which
	avoids incorrectly reenabling machine checks on resume

When MCEs are completely disabled on the command line don't set
up the sysdev devices for them either.

Includes a comment fix from Thomas Gleixner.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Higher priority bug fix

The machine check poller runs a single timer and then broadcasted an
IPI to all CPUs to check them. This leads to unnecessary
synchronization between CPUs. The original CPU running the timer has
to wait potentially a long time for all other CPUs answering. This is
also real time unfriendly and in general inefficient.

This was especially a problem on systems with a lot of events where
the poller run with a higher frequency after processing some events.
There could be more and more CPU time wasted with this, to
the point of significantly slowing down machines.

The machine check polling is actually fully independent per CPU, so
there's no reason to not just do this all with per CPU timers.  This
patch implements that.

Also switch the poller also to use standard timers instead of work
queues. It was using work queues to be able to execute a user program
on a event, but mce_notify_user() handles this case now with a
separate callback. So instead always run the poll code in in a
standard per CPU timer, which means that in the common case of not
having to execute a trigger there will be less overhead.

This allows to clean up the initialization significantly, because
standard timers are already up when machine checks get init'ed.  No
multiple initialization functions.

Thanks to Thomas Gleixner for some help.

Cc: thockin@google.com
v2: Use del_timer_sync() on cpu shutdown and don't try to handle
migrated timers.
v3: Add WARN_ON for timer running on unexpected CPU
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Needed for bug fix in next patch

This relaxes the requirement that mce_notify_user has to run in process
context. Useful for future changes, but also leads to cleaner
behaviour now. Now instead mce_notify_user can be called directly
from interrupt (but not NMI) context.

The work queue only uses a single global work struct, which can be done safely
because it is always free to reuse before the trigger function is executed.
This way no events can be lost.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: low priority bug fix

This removes part of a a patch I added myself some time ago. After some
consideration the patch was a bad idea. In particular it stopped machine check
exceptions during code patching.

To quote the comment:

        * MCEs only happen when something got corrupted and in this
        * case we must do something about the corruption.
        * Ignoring it is worse than a unlikely patching race.
        * Also machine checks tend to be broadcast and if one CPU
        * goes into machine check the others follow quickly, so we don't
        * expect a machine check to cause undue problems during to code
        * patching.

So undo the machine check related parts of
8f4e956b NMIs are still disabled.

This only removes code, the only additions are a new comment.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Bug fix

During suspend it is not reliable to process machine check
exceptions, because CPUs disappear but can still get machine check
broadcasts.  Also the system is slightly more likely to
machine check them, but the handler is typically not a position
to handle them in a meaningfull way.

So disable them during suspend and enable them during resume.

Also make sure they are always disabled on hot-unplugged CPUs.

This new code assumes that suspend always hotunplugs all
non BP CPUs.

v2: Remove the WARN_ONs Thomas objected to.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: bug fix (with tolerant == 3)

do_exit cannot be called directly from the exception handler because
it can sleep and the exception handler runs on the exception stack.
Use force_sig() instead.

Based on a earlier patch by Ying Huang who debugged the problem.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Bug fix

This fixes a long standing bug in the machine check code. On resume the
boot CPU wouldn't get its vendor specific state like thermal handling
reinitialized. This means the boot cpu wouldn't ever get any thermal
events reported again.

Call the respective initialization functions on resume

v2: Remove ancient init because they don't have a resume device anyways.
    Pointed out by Thomas Gleixner.
v3: Now fix the Subject too to reflect v2 change
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: fix disabled MCE after resume

Don't prevent multiple initialization of MCEs.

Back from early prehistory mcheck_init() has a reentry check. Presumably
that was needed in very old kernels to prevent it entering twice.

But as Andreas points out this prevents CPU hotplug (and therefore resume)
to correctly reinitialize MCEs when a AP boots again after being
offlined.

Just drop the check.
Reported-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Tested-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

During CPU hot-remove the sysfs directory created by
threshold_create_bank(), defined in
arch/x86/kernel/cpu/mcheck/mce_amd_64.c, has to be removed before
its parent directory, created by mce_create_device(), defined in
arch/x86/kernel/cpu/mcheck/mce_64.c .  Moreover, when the CPU in
question is hotplugged again, obviously the latter has to be created
before the former.  At present, the right ordering is not enforced,
because all of these operations are carried out by CPU hotplug
notifiers which are not appropriately ordered with respect to each
other.  This leads to serious problems on systems with two or more
multicore AMD CPUs, among other things during suspend and hibernation.

Fix the problem by placing threshold bank CPU hotplug callbacks in
mce_cpu_callback(), so that they are invoked at the right places,
if defined.  Additionally, use kobject_del() to remove the sysfs
directory associated with the kobject created by
kobject_create_and_add() in threshold_create_bank(), to prevent the
kernel from crashing during CPU hotplug operations on systems with
two or more multicore AMD CPUs.

This patch fixes bug #11337.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NAndi Kleen <andi@firstfloor.org>
Tested-by: NMark Langsdorf <mark.langsdorf@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use the new generic int attribute accessors for the x86 mce tolerant
attribute. Simple example to illustrate the new macros.

There are much more places all over the tree that could be converted
like this.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.

I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.

I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.

Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

  * nr_cpu_ids should be used to allocate arrays based on the number of
    cpu's present.
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Quirks getting ignored was a bug. Below patch fixes the bug, until
we have the dynamic banks support.

Sysfs choice configuration should not have any issues with the earlier patch
as we look for NR_SYSFS_BANKS in do_machine_check().
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Max Asbock <masbock@us.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NArnd Bergmann <arnd@arndb.de>

It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

attached is a no-brainer that makes kernel correctly report
NR_BANKS for MCE. We are right now limited to NR_BANKS==6, but the
error message will use the available number of banks instead of the
defined maximum.

For a Nehalem based system it will print:

"MCE: warning: using only 9 banks"

while the correct message would be

"MCE: warning: using only 6 banks"
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Eliminate the 6 bank restriction in 64 bit mce reporting code. This
restriction is artificial (due to static creation of sysfs files) and 32
bit code does not have any such restriction.

This change helps in reporting the details of machine checks on a
machine check exception with errors in bank 6 and above on CPUs that
support those banks. Without the patch, machine check errors in those
banks are not reported.

We still have 128 (MCE_EXTENDED_BANK) bank restriction instead of max
256 supported in hardware. That is not changed in the patch below as it
will have some user level mcelog utility dependency, with bank 128 being
used for thermal reporting currently.

The patch below does not create sysfs control (bankNctl) for banks
higher than 6 as well. That needs some pre-cleanup in /sysfs mce layout,
removal of per cpu /sysfs entries for bankctl as they are really global
system level control today. That change will follow. This basic change
is critical to report the detailed errors on banks higher than 6.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

At least on my Barcelona, I see MCE log entries after cold boot caused
by BIOS not properly clearing the respective registers. Therefore, this
patch extends the workaround to families 0x10 and 0x11 (the latter just
for completeness, I have nothing to verify this against).
At the same time, provide a way to make these entries visible via the
'mce=bootlog' command line option even on these machines.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix following warning:
WARNING: arch/x86/kernel/cpu/mcheck/built-in.o(.text+0x752): Section mismatch: reference to .cpuinit.text:mce_create_device in 'mce_cpu_callback'

mce_cpu_callback() is only used by mce_cpu_notofier.
The notifier is only used for hotplugable cpu's as it is
registered using register_hotcpu_notifier(),

Annotate them both __cpuinit to fix the warning.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The machine check handler registers ioctl handler that is called
with the BKL held. Changing to register unlocked_ioctl instead.
Also mce ioctl handler does not seem to need any lock protection.

To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org

Change the Machine check handler to use unlocked_ioctl instead of
ioctl handler. Also the mce ioctl handler does not need any lock
protection.
Signed-off-by: NNikanth Karthikesan <knikanth@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This requires making die() return a value, making its callers honor
this (and be prepared that it may return), and making oops_end() have
two additional parameters.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Converted to a mutex, and changed the name to mce_read_mutex.
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

We have a lot of code which differs only by the naming of specific
members of structures that contain registers.  In order to enable
additional unifications, this patch drops the e- or r- size prefix
from the register names in struct pt_regs, and drops the x- prefixes
for segment registers on the 32-bit side.

This patch also performs the equivalent renames in some additional
places that might be candidates for unification in the future.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The patch to suppress bitops-related warnings added a pile of ugly
casts.  Many of these were related to the management of x86 CPU
capabilities.  Clean these up by adding specific set/clear_cpu_cap
macros, and use them consistently.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch makes the needlessly global struct mcelog static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>