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Don't skip removing mce_attrs in route from error2.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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We need a cleared cpu_mask to record if mce is initialized, especially
when MAXSMP is used.
used zalloc_... instead
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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The sysfs attribute cmci_disabled was accidentall turned into a
duplicate of ignore_ce, breaking all other attributes.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Conflicts:
arch/x86/kernel/cpu/mcheck/mce_intel.c
Merge reason: merge with an urgent-branch MCE fix.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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mce_intel.c uses apic_write() and lapic_get_maxlvt(), and so it needs
<asm/apic.h>.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
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If APIC was disabled (for some reason) and as result
it's not even mapped we should not try to enable thermal
interrupts at all.
Reported-by: Simon Holm Thøgersen <odie@cs.aau.dk>
Tested-by: Simon Holm Thøgersen <odie@cs.aau.dk>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090615182633.GA7606@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Vegard Nossum reported:
> I get an MCE-related crash like this in latest linus tree:
>
> [ 0.115341] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
> [ 0.116396] CPU: L2 Cache: 512K (64 bytes/line)
> [ 0.120570] mce: CPU supports 0 MCE banks
> [ 0.124870] BUG: unable to handle kernel NULL pointer dereference at 00000000 00000010
> [ 0.128001] IP: [<ffffffff813b98ad>] mcheck_init+0x278/0x320
> [ 0.128001] PGD 0
> [ 0.128001] Thread overran stack, or stack corrupted
> [ 0.128001] Oops: 0002 [#1] PREEMPT SMP
> [ 0.128001] last sysfs file:
> [ 0.128001] CPU 0
> [ 0.128001] Modules linked in:
> [ 0.128001] Pid: 0, comm: swapper Not tainted 2.6.30 #426
> [ 0.128001] RIP: 0010:[<ffffffff813b98ad>] [<ffffffff813b98ad>] mcheck_init+0x278/0x320
> [ 0.128001] RSP: 0018:ffffffff81595e38 EFLAGS: 00000246
> [ 0.128001] RAX: 0000000000000010 RBX: ffffffff8158f900 RCX: 0000000000000000
> [ 0.128001] RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000000000010
> [ 0.128001] RBP: ffffffff81595e68 R08: 0000000000000001 R09: 0000000000000000
> [ 0.128001] R10: 0000000000000010 R11: 0000000000000000 R12: 0000000000000000
> [ 0.128001] R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000000000000
> [ 0.128001] FS: 0000000000000000(0000) GS:ffff880002288000(0000) knlGS:00000
> 00000000000
> [ 0.128001] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 0.128001] CR2: 0000000000000010 CR3: 0000000001001000 CR4: 00000000000006b0
> [ 0.128001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 0.128001] DR3: 0000000000000000 DR6: 0000000000000000 DR7: 0000000000000000
> [ 0.128001] Process swapper (pid: 0, threadinfo ffffffff81594000, task ffffff
> ff8152a4a0)
> [ 0.128001] Stack:
> [ 0.128001] 0000000081595e68 5aa50ed3b4ddbe6e ffffffff8158f900 ffffffff8158f
> 914
> [ 0.128001] ffffffff8158f948 0000000000000000 ffffffff81595eb8 ffffffff813b8
> 69c
> [ 0.128001] 5aa50ed3b4ddbe6e 00000001078bfbfd 0000062300000800 5aa50ed3b4ddb
> e6e
> [ 0.128001] Call Trace:
> [ 0.128001] [<ffffffff813b869c>] identify_cpu+0x331/0x392
> [ 0.128001] [<ffffffff815a1445>] identify_boot_cpu+0x23/0x6e
> [ 0.128001] [<ffffffff815a14ac>] check_bugs+0x1c/0x60
> [ 0.128001] [<ffffffff8159c075>] start_kernel+0x403/0x46e
> [ 0.128001] [<ffffffff8159b2ac>] x86_64_start_reservations+0xac/0xd5
> [ 0.128001] [<ffffffff8159b3ea>] x86_64_start_kernel+0x115/0x14b
> [ 0.128001] [<ffffffff8159b140>] ? early_idt_handler+0x0/0x71
This happens on QEMU which reports MCA capability, but no banks.
Without this patch there is a buffer overrun and boot ops because
the code would try to initialize the 0 element of a zero length
kmalloc() buffer.
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <20090615125200.GD31969@one.firstfloor.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Rename files that are no longer 64bit specific:
mce_amd_64.c => mce_amd.c
mce_intel_64.c => mce_intel.c
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Now all symbols in the header are static. Remove the header.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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and make intel_thermal_interrupt() static.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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move intel_init_thermal() into therm_throt.c
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Put common functions into therm_throt.c, modify Makefile.
unexpected_thermal_interrupt
intel_thermal_interrupt
smp_thermal_interrupt
intel_set_thermal_handler
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Let them in same shape.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Break smp_thermal_interrupt() into two functions.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Remove unused argument regs from handlers, and use inc_irq_stat.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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The mce_disabled on 32bit is a tristate variable [1,0,-1],
while 64bit version is boolean [0,1].
This patch makes mce_disabled always boolean, and use mce_p5_enabled
to indicate the third state instead.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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There are 2 headers:
arch/x86/include/asm/mce.h
arch/x86/kernel/cpu/mcheck/mce.h
and in the latter small header:
#include <asm/mce.h>
This patch move all contents in the latter header into the former,
and fix all files using the latter to include the former instead.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Add sysfs interface for admins who want to tweak these options without
rebooting the system.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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"trigger" is not straight forward name for valiable that holds name
of user mode helper program which triggered by machine check events.
This patch renames this valiable and kins to more recognizable names.
trigger => mce_helper
trigger_argv => mce_helper_argv
notify_user => mce_need_notify
No functional changes.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Add __read_mostly to data written during setup.
Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Simplify interface of mce_start():
- no_way_out = mce_start(no_way_out, &order);
+ order = mce_start(&no_way_out);
Now Monarch and Subjects share same exit(return) in usual path.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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In mce_cpu_restart, mce_init_timer is called unconditionally.
If !mce_available (e.g. mce is disabled), there are no useful work
for timer. Stop running it.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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If one CPU has no_way_out == 1, all other CPUs should have no_way_out
== 1. But despite global_nwo is read after mce_callin, global_nwo is
updated after mce_callin too. So it is possible that some CPU read
global_nwo before some other CPU update global_nwo, so that no_way_out
== 1 for some CPU, while no_way_out == 0 for some other CPU.
This patch fixes this race condition via moving mce_callin updating
after global_nwo updating, with a smp_wmb in between. A smp_rmb is
added between their reading too.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
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Conflicts:
arch/x86/kernel/cpu/mcheck/mce_64.c
arch/x86/kernel/irq.c
Merge reason: Resolve the conflicts above.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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* 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (138 commits)
KVM: Prevent overflow in largepages calculation
KVM: Disable large pages on misaligned memory slots
KVM: Add VT-x machine check support
KVM: VMX: Rename rmode.active to rmode.vm86_active
KVM: Move "exit due to NMI" handling into vmx_complete_interrupts()
KVM: Disable CR8 intercept if tpr patching is active
KVM: Do not migrate pending software interrupts.
KVM: inject NMI after IRET from a previous NMI, not before.
KVM: Always request IRQ/NMI window if an interrupt is pending
KVM: Do not re-execute INTn instruction.
KVM: skip_emulated_instruction() decode instruction if size is not known
KVM: Remove irq_pending bitmap
KVM: Do not allow interrupt injection from userspace if there is a pending event.
KVM: Unprotect a page if #PF happens during NMI injection.
KVM: s390: Verify memory in kvm run
KVM: s390: Sanity check on validity intercept
KVM: s390: Unlink vcpu on destroy - v2
KVM: s390: optimize float int lock: spin_lock_bh --> spin_lock
KVM: s390: use hrtimer for clock wakeup from idle - v2
KVM: s390: Fix memory slot versus run - v3
...
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This patch introduces three boot options (no_cmci, dont_log_ce
and ignore_ce) to control handling for corrected errors.
The "mce=no_cmci" boot option disables the CMCI feature.
Since CMCI is a new feature so having boot controls to disable
it will be a help if the hardware is misbehaving.
The "mce=dont_log_ce" boot option disables logging for corrected
errors. All reported corrected errors will be cleared silently.
This option will be useful if you never care about corrected
errors.
The "mce=ignore_ce" boot option disables features for corrected
errors, i.e. polling timer and cmci. All corrected events are
not cleared and kept in bank MSRs.
Usually this disablement is not recommended, however it will be
a help if there are some conflict with the BIOS or hardware
monitoring applications etc., that clears corrected events in
banks instead of OS.
[ And trivial cleanup (space -> tab) for doc is included. ]
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <4A30ACDF.5030408@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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This patch:
- Adds print_mce_head() instead of first flag
- Makes the header to be printed always
- Stops double printing of corrected errors
[ This portion originates from Huang Ying's patch ]
Originally-From: Huang Ying <ying.huang@intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
LKML-Reference: <4A30AC83.5010708@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, nmi: Use predefined numbers instead of hardcoded one
x86: asm/processor.h: remove double declaration
x86, mtrr: replace MTRRdefType_MSR with msr-index's MSR_MTRRdefType
x86, mtrr: replace MTRRfix4K_C0000_MSR with msr-index's MSR_MTRRfix4K_C0000
x86, mtrr: remove mtrr MSRs double declaration
x86, mtrr: replace MTRRfix16K_80000_MSR with msr-index's MSR_MTRRfix16K_80000
x86, mtrr: replace MTRRfix64K_00000_MSR with msr-index's MSR_MTRRfix64K_00000
x86, mtrr: replace MTRRcap_MSR with msr-index's MSR_MTRRcap
x86: mce: remove duplicated #include
x86: msr-index.h remove duplicate MSR C001_0015 declaration
x86: clean up arch/x86/kernel/tsc_sync.c a bit
x86: use symbolic name for VM86_SIGNAL when used as vm86 default return
x86: added 'ifndef _ASM_X86_IOMAP_H' to iomap.h
x86: avoid multiple declaration of kstack_depth_to_print
x86: vdso/vma.c declare vdso_enabled and arch_setup_additional_pages before they get used
x86: clean up declarations and variables
x86: apic/x2apic_cluster.c x86_cpu_to_logical_apicid should be static
x86 early quirks: eliminate unused function
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VT-x needs an explicit MC vector intercept to handle machine checks in the
hyper visor.
It also has a special option to catch machine checks that happen
during VT entry.
Do these interceptions and forward them to the Linux machine check
handler. Make it always look like user space is interrupted because
the machine check handler treats kernel/user space differently.
Thanks to Jiang Yunhong for help and testing.
Cc: stable@kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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These are defined as static cpumask_var_t so if MAXSMP is not used,
they are cleared already. Avoid surprises when MAXSMP is enabled.
Signed-off-by: Yinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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Newer Intel CPUs support a new class of machine checks called recoverable
action optional.
Action Optional means that the CPU detected some form of corruption in
the background and tells the OS about using a machine check
exception. The OS can then take appropiate action, like killing the
process with the corrupted data or logging the event properly to disk.
This is done by the new generic high level memory failure handler added
in a earlier patch. The high level handler takes the address with the
failed memory and does the appropiate action, like killing the process.
In this version of the patch the high level handler is stubbed out
with a weak function to not create a direct dependency on the hwpoison
branch.
The high level handler cannot be directly called from the machine check
exception though, because it has to run in a defined process context to
be able to sleep when taking VM locks (it is not expected to sleep for a
long time, just do so in some exceptional cases like lock contention)
Thus the MCE handler has to queue a work item for process context,
trigger process context and then call the high level handler from there.
This patch adds two path to process context: through a per thread kernel
exit notify_user() callback or through a high priority work item.
The first runs when the process exits back to user space, the other when
it goes to sleep and there is no higher priority process.
The machine check handler will schedule both, and whoever runs first
will grab the event. This is done because quick reaction to this
event is critical to avoid a potential more fatal machine check
when the corruption is consumed.
There is a simple lock less ring buffer to queue the corrupted
addresses between the exception handler and the process context handler.
Then in process context it just calls the high level VM code with
the corrupted PFNs.
The code adds the required code to extract the failed address from
the CPU's machine check registers. It doesn't try to handle all
possible cases -- the specification has 6 different ways to specify
memory address -- but only the linear address.
Most of the required checking has been already done earlier in the
mce_severity rule checking engine. Following the Intel
recommendations Action Optional errors are only enabled for known
situations (encoded in MCACODs). The errors are ignored otherwise,
because they are action optional.
v2: Improve comment, disable preemption while processing ring buffer
(reported by Ying Huang)
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>
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Rename the mce_notify_user function to mce_notify_irq. The next
patch will split the wakeup handling of interrupt context
and of process context and it's better to give it a clearer
name for this.
Contains a fix from Ying Huang
[ Impact: cleanup ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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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: Huang Ying <ying.huang@intel.com>
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>
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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: 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>
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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: 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>
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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: 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>
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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: Huang Ying <ying.huang@intel.com>
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>
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... 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: 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>
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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: 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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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