The MCE subsystem needs to sample an RCU-protected index outside of
any protection for that index.  If this was a pointer, we would use
rcu_access_pointer(), but there is no corresponding rcu_access_index().
This commit therefore creates an rcu_access_index() and applies it
to MCE.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NZdenek Kabelac <zkabelac@redhat.com>

Some subsystems in the x86 tree need to carry out suspend/resume and
shutdown operations with one CPU on-line and interrupts disabled and
they define sysdev classes and sysdevs or sysdev drivers for this
purpose.  This leads to unnecessarily complicated code and excessive
memory usage, so switch them to using struct syscore_ops objects for
this purpose instead.

Generally, there are three categories of subsystems that use
sysdevs for implementing PM operations: (1) subsystems whose
suspend/resume callbacks ignore their arguments entirely (the
majority), (2) subsystems whose suspend/resume callbacks use their
struct sys_device argument, but don't really need to do that,
because they can be implemented differently in an arguably simpler
way (io_apic.c), and (3) subsystems whose suspend/resume callbacks
use their struct sys_device argument, but the value of that argument
is always the same and could be ignored (microcode_core.c).  In all
of these cases the subsystems in question may be readily converted to
using struct syscore_ops objects for power management and shutdown.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>

They were generated by 'codespell' and then manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: trivial@kernel.org
LKML-Reference: <1300389856-1099-3-git-send-email-lucas.demarchi@profusion.mobi>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Replace all uses of current_cpu_data with this_cpu operations on the
per cpu structure cpu_info.  The scala accesses are replaced with the
matching this_cpu ops which results in smaller and more efficient
code.

In the long run, it might be a good idea to remove cpu_data() macro
too and use per_cpu macro directly.

tj: updated description

Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Go through x86 code and replace __get_cpu_var and get_cpu_var
instances that refer to a scalar and are not used for address
determinations.

Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: N"H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>

Notify all parties registered on the mce decoder chain about logged
correctable MCEs.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Acked-by: NDoug Thompson <dougthompson@xmission.com>
Acked-by: NIngo Molnar <mingo@elte.hu>

The mce processing applies rcu_dereference_check() to integers used as
array indices.  This patch therefore moves mce to the new RCU API
rcu_dereference_index_check() that avoids the sparse processing that
would otherwise result in compiler errors.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>

Use HW_ERR printk prefix in MCE handler. To make it more explicit that
this is hardware error instead of software error.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
LKML-Reference: <1275978939.3444.668.camel@yhuang-dev.sh.intel.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Traditionally, fatal MCE will cause Linux print error log to console
then reboot. Because MCE registers will preserve their content after
warm reboot, the hardware error can be logged to disk or network after
reboot. But system may fail to warm reboot, then you may lose the
hardware error log. ERST can help here. Through saving the hardware
error log into flash via ERST before go panic, the hardware error log
can be gotten from the flash after system boot successful again.

The fatal MCE processing procedure with ERST involved is as follow:

- Hardware detect error, MCE raised
- MCE read MCE registers, check error severity (fatal), prepare error record
- Write MCE error record into flash via ERST
- Go panic, then trigger system reboot
- System reboot, /sbin/mcelog run, it reads /dev/mcelog to check flash
  for error record of previous boot via ERST, and output and clear
  them if available
- /sbin/mcelog logs error records into disk or network

ERST only accepts CPER record format, but there is no pre-defined CPER
section can accommodate all information in struct mce, so a customized
section type is defined to hold struct mce inside a CPER record as an
error section.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

edac_mce module is an interface module that gets mcelog data and
forwards to any registered edac module that expects to receive data via
mce.
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

... generating slightly smaller code.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <4BCF261F020000780003B33C@vpn.id2.novell.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Commit f56e8a07 "x86/mce: Fix RCU lockdep splats" introduced the
following build bug:

  arch/x86/kernel/cpu/mcheck/mce.c: In function 'mce_log':
  arch/x86/kernel/cpu/mcheck/mce.c:166: error: 'mce_read_mutex' undeclared (first use in this function)
  arch/x86/kernel/cpu/mcheck/mce.c:166: error: (Each undeclared identifier is reported only once
  arch/x86/kernel/cpu/mcheck/mce.c:166: error: for each function it appears in.)

Move the in-the-middle-of-file lock variable up to the variable
definition section, the top of the .c file.

Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267830207-9474-3-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Create an rcu_dereference_check_mce() that checks for RCU-sched
read side and mce_read_mutex being held on update side.  Replace
uses of rcu_dereference() in arch/x86/kernel/cpu/mcheck/mce.c
with this new macro.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267830207-9474-3-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

These are the non-static sysfs attributes that exist on
my test machine.  Fix them to use sysfs_attr_init or
sysfs_bin_attr_init as appropriate.   It simply requires
making a sysfs attribute present to see this.  So this
is a little bit tedious but otherwise not too bad.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Commit cebe1820 had an unnecessary,
wrong change: &mce_banks[i].attr is equivalent to the former
bank_attrs[i], not to mce_attrs[i].
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: NAndi Kleen <andi@firstfloor.org>
LKML-Reference: <4B1E05CC.4040703f@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

mce_timer must be passed to setup_timer() in all cases, no
matter whether it is going to be actually used. Otherwise, when
the CPU gets brought down, its call to del_timer_sync() will
never return, as the timer won't have a base associated, and
hence lock_timer_base() will loop infinitely.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: <stable@kernel.org>
LKML-Reference: <4B1DB831.2030801@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Even it is in error path unlikely taken, add_timer_on() at
CPU_DOWN_FAILED* needs to be skipped if mce_timer is disabled.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: <stable@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The mce_disable_cpu() and mce_reenable_cpu() are called only
from mce_cpu_callback() which is marked as __cpuinit.
So these functions can be __cpuinit too.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <4B0E3C4E.4090809@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The intel_init_thermal() is called from resume path, so it
cannot be marked as __init.

OTOH mce_banks_init() is only called from
__mcheck_cpu_cap_init() which is marked as __cpuinit, so it can
be also marked as __cpuinit.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: NYong Wang <yong.y.wang@linux.intel.com>
LKML-Reference: <4AFBB0B8.2070501@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On platforms where the BIOS handles the thermal monitor interrupt,
APIC_LVTTHMR on each logical CPU is programmed to generate a SMI
and OS must not touch it.

Unfortunately AP bringup sequence using INIT-SIPI-SIPI clears all
the LVT entries except the mask bit. Essentially this results in
all LVT entries including the thermal monitoring interrupt set
to masked (clearing the bios programmed value for APIC_LVTTHMR).

And this leads to kernel take over the thermal monitoring
interrupt on AP's but not on BSP (leaving the bios programmed
value only on BSP).

As a result of this, we have seen system hangs when the thermal
monitoring interrupt is generated.

Fix this by reading the initial value of thermal LVT entry on
BSP and if bios has taken over the control, then program the
same value on all AP's and leave the thermal monitoring
interrupt control on all the logical cpu's to the bios.
Signed-off-by: NYong Wang <yong.y.wang@intel.com>
Reviewed-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <20091110013824.GA24940@ywang-moblin2.bj.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: stable@kernel.org

Add an early initcall (pre SMP) which sets up global MCE
functionality.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <1255689093-26921-2-git-send-email-borislav.petkov@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Prefix global/setup routines with "mcheck_" thus differentiating
from the internal facilities prefixed with "mce_". Also, prefix
the per cpu calls with mcheck_cpu and rename them to reflect the
MCE setup hierarchy of calls better.

There should be no functionality change resulting from this
patch.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <1255689093-26921-1-git-send-email-borislav.petkov@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The MCE initialization code explicitly says it doesn't handle
asymmetric configurations where different CPUs support different
numbers of MCE banks, and it prints a big warning in that case.

Therefore, printing the "mce: CPU supports <x> MCE banks"
message into the kernel log for every CPU is pure redundancy
that clutters the log significantly for systems with lots of
CPUs.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
LKML-Reference: <adaeip473qt.fsf@cisco.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This approach is the first baby step towards solving many of the
structural problems the x86 MCE logging code is having today:

 - It has a private ring-buffer implementation that has a number
   of limitations and has been historically fragile and buggy.

 - It is using a quirky /dev/mcelog ioctl driven ABI that is MCE
   specific. /dev/mcelog is not part of any larger logging
   framework and hence has remained on the fringes for many years.

 - The MCE logging code is still very unclean partly due to its ABI
   limitations. Fields are being reused for multiple purposes, and
   the whole message structure is limited and x86 specific to begin
   with.

All in one, the x86 tree would like to move away from this private
implementation of an event logging facility to a broader framework.

By using perf events we gain the following advantages:

 - Multiple user-space agents can access MCE events. We can have an
   mcelog daemon running but also a system-wide tracer capturing
   important events in flight-recorder mode.

 - Sampling support: the kernel and the user-space call-chain of MCE
   events can be stored and analyzed as well. This way actual patterns
   of bad behavior can be matched to precisely what kind of activity
   happened in the kernel (and/or in the app) around that moment in
   time.

 - Coupling with other hardware and software events: the PMU can track a
   number of other anomalies - monitoring software might chose to
   monitor those plus the MCE events as well - in one coherent stream of
   events.

 - Discovery of MCE sources - tracepoints are enumerated and tools can
   act upon the existence (or non-existence) of various channels of MCE
   information.

 - Filtering support: we just subscribe to and act upon the events we
   are interested in. Then even on a per event source basis there's
   in-kernel filter expressions available that can restrict the amount
   of data that hits the event channel.

 - Arbitrary deep per cpu buffering of events - we can buffer 32
   entries or we can buffer as much as we want, as long as we have
   the RAM.

 - An NMI-safe ring-buffer implementation - mappable to user-space.

 - Built-in support for timestamping of events, PID markers, CPU
   markers, etc.

 - A rich ABI accessible over system call interface. Per cpu, per task
   and per workload monitoring of MCE events can be done this way. The
   ABI itself has a nice, meaningful structure.

 - Extensible ABI: new fields can be added without breaking tooling.
   New tracepoints can be added as the hardware side evolves. There's
   various parsers that can be used.

 - Lots of scheduling/buffering/batching modes of operandi for MCE
   events. poll() support. mmap() support. read() support. You name it.

 - Rich tooling support: even without any MCE specific extensions added
   the 'perf' tool today offers various views of MCE data: perf report,
   perf stat, perf trace can all be used to view logged MCE events and
   perhaps correlate them to certain user-space usage patterns. But it
   can be used directly as well, for user-space agents and policy action
   in mcelog, etc.

With this we hope to achieve significant code cleanup and feature
improvements in the MCE code, and we hope to be able to drop the
/dev/mcelog facility in the end.

This patch is just a plain dumb dump of mce_log() records to
the tracepoints / perf events framework - a first proof of
concept step.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <4AD42A0D.7050104@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add an atomic notifier which ensures proper locking when conveying
MCE info to EDAC for decoding. The actual notifier call overrides a
default, negative priority notifier.

Note: make sure we register the default decoder only once since
mcheck_init() runs on each CPU.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20091003065752.GA8935@liondog.tnic>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make decoding of MCEs happen only on AMD hardware by registering a
non-default callback only on CPU families which support it.

While looking at the interaction of decode_mce() with the other MCE
code i also noticed a few other things and made the following
cleanups/fixes:

 - Fixed the mce_decode() weak alias - a weak alias is really not
   good here, it should be a proper callback. A weak alias will be
   overriden if a piece of code is built into the kernel - not
   good, obviously.

 - The patch initializes the callback on AMD family 10h and 11h.

 - Added the more correct fallback printk of:

	No support for human readable MCE decoding on this CPU type.
	Transcribe the message and run it through 'mcelog --ascii' to decode.

   On CPUs that dont have a decoder.

 - Made the surrounding code more readable.

Note that the callback allows us to have a default fallback -
without having to check the CPU versions during the printout
itself. When an EDAC module registers itself, it can install the
decode-print function.

(there's no unregister needed as this is core code.)

version -v2 by Borislav Petkov:

 - add K8 to the set of supported CPUs

 - always build in edac_mce_amd since we use an early_initcall now

 - fix checkpatch warnings
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <20091001141432.GA11410@aftab>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This reverts commit 22223c9b, as
requested by Andi Kleen:

  "Obviously kernels compiled with AMD support can still run on non AMD
   systems, so messages like this can never be removed at compile time."
Requsted-by: NAndi Kleen <andi@firstfloor.org>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use rdmsrl_safe() when accessing MCE registers. While in
theory we always 'know' which ones are safe to access from
the capability bits, there's a lot of hardware variations
and reality might differ from theory, as it did in this case:

   http://bugzilla.kernel.org/show_bug.cgi?id=14204

[    0.010016] mce: CPU supports 5 MCE banks
[    0.011029] general protection fault: 0000 [#1]
[    0.011998] last sysfs file:
[    0.011998] Modules linked in:
[    0.011998]
[    0.011998] Pid: 0, comm: swapper Not tainted (2.6.31_router #1) HP Vectra
[    0.011998] EIP: 0060:[<c100d9b9>] EFLAGS: 00010246 CPU: 0
[    0.011998] EIP is at mce_rdmsrl+0x19/0x60
[    0.011998] EAX: 00000000 EBX: 00000001 ECX: 00000407 EDX: 08000000
[    0.011998] ESI: 00000000 EDI: 8c000000 EBP: 00000405 ESP: c17d5eac

So WARN_ONCE() instead of crashing the box.

( also fix a number of stylistic inconsistencies in the code. )

Note, we might still crash in wrmsrl() if we get that far, but
we shouldnt if the registers are truly inaccessible.
Reported-by: NGNUtoo <GNUtoo@no-log.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <bug-14204-5438@http.bugzilla.kernel.org/>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Now that decoding is done in-kernel, suppress mcelog message part.

CC: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>

Move NB decoder along with required defines to EDAC MCE core. Add
registration routines for further decoding of the MCE info in the AMD64
EDAC module.

CC: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>

If MCE handler is called but none of mces_seen have machine
check event which might signal the MCE (i.e. event higher than
MCE_KEEP_SEVERITY), panic with "Machine check from unknown
source" will be taken since the MCE is assumed to be signaled
from external agent or so.

Usually mces_seen never point MCE_KEEP_SEVERITY event such as
CE. But it can happen because initial value of mces_seen is
accidentally modified by mce_no_way_out() - in case if
mce_no_way_out() run through all banks and the last bank has
the CE, mces_seen points the CE and the "panic by unknown" will
not be taken.

This patch fixes this undesired behavior, and clarifies the logic.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Dongming <jin.dongming@np.css.fujitsu.com>
LKML-Reference: <4A94E244.3020301@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Reported-by: NJin Dongming <jin.dongming@np.css.fujitsu.com>

An older test-box started hanging at the following point during
bootup:

 [    0.022996] Mount-cache hash table entries: 512
 [    0.024996] Initializing cgroup subsys debug
 [    0.025996] Initializing cgroup subsys cpuacct
 [    0.026995] Initializing cgroup subsys devices
 [    0.027995] Initializing cgroup subsys freezer
 [    0.028995] mce: CPU supports 5 MCE banks

I've bisected it down to commit 4efc0670 ("x86, mce: use 64bit
machine check code on 32bit"), which utilizes the MCE code on
32-bit systems too.

The problem is caused by this detail in my config:

  # CONFIG_CPU_SUP_INTEL is not set

This disables the quirks in mce_cpu_quirks() but still enables
MCE support - which then hangs due to the missing quirk
workaround needed on this CPU:

	if (c->x86 == 6 && c->x86_model < 0x1A && banks > 0)
		mce_banks[0].init = 0;

The safe solution is to not initialize MCEs if we dont know on
what CPU we are running (or if that CPU's support code got
disabled in the config).

Also be a bit more defensive on 32-bit systems: dont do a
boot-time dump of pending MCEs not just on the specific system
that we found a problem with (Pentium-M), but earlier ones as
well.

Now this problem is probably not common and disabling CPU
support is rare - but still being more defensive in something
we turned on for a wide range of CPUs is prudent.

Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
LKML-Reference: Message-ID: <4A88E3E4.40506@jp.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On my legacy Pentium M laptop (Acer Extensa 2900) I get bogus MCE on a cold
boot with CONFIG_X86_NEW_MCE enabled, i.e. (after decoding it with mcelog):

MCE 0
HARDWARE ERROR. This is *NOT* a software problem!
Please contact your hardware vendor
CPU 0 BANK 1 MCG status:
MCi status:
Error overflow
Uncorrected error
Error enabled
Processor context corrupt
MCA: Data CACHE Level-1 UNKNOWN Error
STATUS f200000000000195 MCGSTATUS 0

[ The other STATUS values observed: f2000000000001b5 (... UNKNOWN error)
  and f200000000000115 (... READ Error).

  To verify that this is not a CONFIG_X86_NEW_MCE bug I also modified
  the CONFIG_X86_OLD_MCE code (which doesn't log any MCEs) to dump
  content of STATUS MSR before it is cleared during initialization. ]

Since the bogus MCE results in a kernel taint (which in turn disables
lockdep support) don't log boot MCEs on Pentium M (model == 13) CPUs
by default ("mce=bootlog" boot parameter can be be used to get the old
behavior).
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If "fake panic" mode is turned on, just log panic message instead of
go real panic. This is used for testing only, so that the test suite
can check for the correct panic message and do regression testing for
MCE would go panic.

This patch is based on x86-tip.git/mce.

ChangeLog:

v5:

- Rebased on x86-tip.git/mce

v4:

- Move config file from sysfs to debugfs
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Because more debugfs files under mce dir will be create in mce.c.

ChangeLog:

v5:

- Rebased on x86-tip.git/mce
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

mce_cap_init() and mce_cpu_quirks() can be tagged with __cpuinit.
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

"mce argument mce ignored. Please use /sys" message shouldn't
be printed when using "mce" boot option.
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

On my legacy Pentium M laptop (Acer Extensa 2900) I get bogus MCE on a cold
boot with CONFIG_X86_NEW_MCE enabled, i.e. (after decoding it with mcelog):

MCE 0
HARDWARE ERROR. This is *NOT* a software problem!
Please contact your hardware vendor
CPU 0 BANK 1 MCG status:
MCi status:
Error overflow
Uncorrected error
Error enabled
Processor context corrupt
MCA: Data CACHE Level-1 UNKNOWN Error
STATUS f200000000000195 MCGSTATUS 0

[ The other STATUS values observed: f2000000000001b5 (... UNKNOWN error)
  and f200000000000115 (... READ Error).

  To verify that this is not a CONFIG_X86_NEW_MCE bug I also modified
  the CONFIG_X86_OLD_MCE code (which doesn't log any MCEs) to dump
  content of STATUS MSR before it is cleared during initialization. ]

Since the bogus MCE results in a kernel taint (which in turn disables
lockdep support) don't log boot MCEs on Pentium M (model == 13) CPUs
by default ("mce=bootlog" boot parameter can be be used to get the old
behavior).
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reviewed-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>