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>
Document that check_interval set to 0 means no polling.
Noticed by Hidetoshi Seto
Also add a reference from boot options to the sysfs tunables
Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.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>
cgroup documentation was moved to Documentation/cgroups/. There are some
places that still refer to Documentation/controllers/,
Documentation/cgroups.txt and Documentation/cpusets.txt. Fix those.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Impact: documentation update
Commit a6523748bd
(paravirt/x86, 64-bit: move __PAGE_OFFSET to leave a space for hypervisor)
changed address space without changing the documentation.
Change it according to the code change -- direct mapping start:
ffff810000000000 => ffff880000000000 which gives 57 TiB, something
between 45 and 46 bits.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: documentation update
1) nmi_watchdog boot parameter is common to 32/64 bit modes. So
move it from Documentation/x86/x86_64/boot-options.txt to
Documentation/kernel-parameters.txt and integrate with.
2) Also fix [panic] keyword placement -- it ought to be at first
position otherwise it will not be recognized.
3) Document lapic and ioapic keywords.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The Documentation/i386 and Documentation/x86_64 directories and their
contents have been moved into Documentation/x86. Fix references to
those files accordingly.
Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit ecd29476ae removed the
"disable_8254_timer" and "enable_8254_timer" kernel parameters from
the kernel but did not remove the references to them from two
files in the Documentation directory: kernel-parameters.txt and
x86/x86_64/boot-options.txt.
This change completes the removal.
Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Acked-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Applies on top of the previous patch:
x86 boot: add code to add BIOS provided EFI memory entries to kernel
Instead of always adding EFI memory map entries (if present) to the
memory map after initially finding either E820 BIOS memory map entries
and/or kernel command line memmap entries, -instead- only add such
additional EFI memory map entries if the kernel boot option:
add_efi_memmap
is specified.
Requiring this 'add_efi_memmap' option is backward compatible with
kernels that didn't load such additional EFI memory map entries in
the first place, and it doesn't override a configuration that tries
to replace all E820 or EFI BIOS memory map entries with ones given
entirely on the kernel command line.
Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: "Yinghai Lu" <yhlu.kernel@gmail.com>
Cc: "Jack Steiner" <steiner@sgi.com>
Cc: "Mike Travis" <travis@sgi.com>
Cc: "Huang
Cc: Ying" <ying.huang@intel.com>
Cc: "Andi Kleen" <andi@firstfloor.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The current organization of the x86 documentation makes it appear as
if the "i386" documentation doesn't apply to x86-64, which is does.
Thus, move that documentation into Documentation/x86, and move the
x86-64-specific stuff into Documentation/x86/x86_64 with the eventual
goal to move stuff that isn't actually 64-bit specific back into
Documentation/x86.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
