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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Ying Huang <ying.huang@intel.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Throttling logic is broken and we can lock up with too small
hw sampling intervals.
Make the throttling code more robust: disable counters even
if we already disabled them.
( Also clean up whitespace damage i noticed while reading
various pieces of code related to throttling. )
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The UV tlb shootdown code has a serious initialization error.
An array of structures [32*8] is initialized as if it were [32].
The array is indexed by (cpu number on the blade)*8, so the short
initialization works for up to 4 cpus on a blade.
But above that, we provide an invalid opcode to the hub's
broadcast assist unit.
This patch changes the allocation of the array to use its symbolic
dimensions for better clarity. And initializes all 32*8 entries.
Shortened 'UV_ACTIVATION_DESCRIPTOR_SIZE' to 'UV_ADP_SIZE' per Ingo's
recommendation.
Tested on the UV simulator.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: <stable@kernel.org>
LKML-Reference: <E1M6lZR-0007kV-Aq@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In alloc_coherent there is an omitted unlock on the path where mapping
fails. Add the unlock.
[ Impact: fix lock imbalance in alloc_coherent ]
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This patch resets the bit in dr6 after the corresponding exception is
handled in code, so that we keep a clean track of the current virtual debug
status register.
[ Impact: keep track of breakpoints triggering completion ]
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch disables Hardware breakpoints before doing a 'kexec' on the machine
so that the cpu doesn't keep debug registers values which would be out of
sync for the new image.
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch enables the use of abstract debug registers in
process-handling routines, according to the new hardware breakpoint
Api.
[ Impact: adapt thread breakpoints handling code to the new breakpoint Api ]
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch enables the use of wrapper routines to access the debug/breakpoint
registers on cpu management.
The hardcoded debug registers save and restore operations for threads
breakpoints are replaced by wrappers.
And now that we handle the kernel breakpoints too, we also need to handle them
on cpu hotplug operations.
[ Impact: adapt new hardware breakpoint api to cpu hotplug ]
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch modifies the breakpoint exception handler code to use the new
abstract debug register names.
[ fweisbec@gmail.com: fix conflict against kmemcheck ]
[ Impact: refactor and cleanup x86 debug exception handler ]
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch introduces the arch-specific implementation of the generic
hardware breakpoints in kernel/hw_breakpoint.c inside x86 specific directories.
It contains functions which help to validate and serve requests using
Hardware Breakpoint registers on x86 processors.
[ fweisbec@gmail.com: fix conflict against kmemcheck ]
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
The generic hardware breakpoint interface provides an abstraction of
hardware breakpoints in front of specific arch implementations for both kernel
and user side breakpoints.
This includes execution breakpoints and read/write breakpoints, also known as
"watchpoints".
This patch introduces header files containing constants, structure definitions
and declaration of functions used by the hardware breakpoint core and x86
specific code.
It also introduces an array based storage for the debug-register values in
'struct thread_struct', while modifying all users of debugreg<n> member in the
structure.
[ Impact: add headers for new hardware breakpoint interface ]
Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Fix the fact that the IOAPIC version number in the x86_64 code path always
gets assigned to 0, instead of the correct value.
Before the patch: (from "dmesg" output):
ACPI: IOAPIC (id[0x08] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 8, version 0, address 0xfec00000, GSI 0-23 <---
After the patch:
ACPI: IOAPIC (id[0x08] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 8, version 32, address 0xfec00000, GSI 0-23 <---
History:
io_apic_get_version() was compiled out of the x86_64 code path in the commit
f2c2cca3ac:
Author: Andi Kleen <ak@suse.de>
Date: Tue Sep 26 10:52:37 2006 +0200
[PATCH] Remove APIC version/cpu capability mpparse checking/printing
ACPI went to great trouble to get the APIC version and CPU capabilities
of different CPUs before passing them to the mpparser. But all
that data was used was to print it out. Actually it even faked some data
based on the boot cpu, not on the actual CPU being booted.
Remove all this code because it's not needed.
Cc: len.brown@intel.com
At the time, the IOAPIC version number was deliberately not printed
in the x86_64 code path. However, after the x86 and x86_64 files were
merged, the net result is that the IOAPIC version is printed incorrectly
in the x86_64 code path.
The patch below provides a fix. I have tested it with acpi, and with
acpi=off, and did not see any problems.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Acked-by: Yinghai Lu <yhlu.kernel@gmail.com>
LKML-Reference: <20090416014230.4885.94926.sendpatchset@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
*************************
Merge reason: arch/x86/kernel/irqinit_{32,64}.c unified in irq/numa
and modified in x86/mce3; this merge resolves the conflict.
Conflicts:
arch/x86/kernel/irqinit.c
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Merge reason: irq/numa didnt build because this commit:
2759c32: x86: don't call read_apic_id if !cpu_has_apic
Had a dependency on x86/cpufeature changes. Pull in that
(small) branch to fix the dependency.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
arch/mips/sibyte/bcm1480/irq.c
arch/mips/sibyte/sb1250/irq.c
Merge reason: we gathered a few conflicts plus update to latest upstream fixes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge reason: merge almost-rc8 into perfcounters/core, which was -rc6
based - to pick up the latest upstream fixes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix for:
WARNING: space prohibited between function name and open parenthesis '('
+ for_each_online_cpu (cpu) {
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: H. 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: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: H. 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: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. 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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Fix style of winged comment in mce-inject.c.
[ Impact: comment only ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Add a comment explaining that mce_chrdev_ops is intentionally
writable.
[ Impact: comment only ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
