GitLab

Now, multiple CPUs can receive an external NMI simultaneously by
specifying the "apic_extnmi=all" command line parameter. When we take
a crash dump by using external NMI with this option, we fail to save
registers into the crash dump. This happens as follows:

  CPU 0                              CPU 1
  ================================   =============================
  receive an external NMI
  default_do_nmi()                   receive an external NMI
    spin_lock(&nmi_reason_lock)      default_do_nmi()
    io_check_error()                   spin_lock(&nmi_reason_lock)
      panic()                            busy loop
      ...
        kdump_nmi_shootdown_cpus()
          issue NMI IPI -----------> blocked until IRET
                                         busy loop...

Here, since CPU 1 is in NMI context, an additional NMI from CPU 0
remains unhandled until CPU 1 IRETs. However, CPU 1 will never execute
IRET so the NMI is not handled and the callback function to save
registers is never called.

To solve this issue, we check if the IPI for crash dumping was issued
while waiting for nmi_reason_lock to be released, and if so, call its
callback function directly. If the IPI is not issued (e.g. kdump is
disabled), the actual behavior doesn't change.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20151210065245.4587.39316.stgit@softrs

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Currently, kdump_nmi_shootdown_cpus(), a subroutine of crash_kexec(),
sends an NMI IPI to CPUs which haven't called panic() to stop them,
save their register information and do some cleanups for crash dumping.
However, if such a CPU is infinitely looping in NMI context, we fail to
save its register information into the crash dump.

For example, this can happen when unknown NMIs are broadcast to all
CPUs as follows:

  CPU 0                             CPU 1
  ===========================       ==========================
  receive an unknown NMI
  unknown_nmi_error()
    panic()                         receive an unknown NMI
      spin_trylock(&panic_lock)     unknown_nmi_error()
      crash_kexec()                   panic()
                                        spin_trylock(&panic_lock)
                                        panic_smp_self_stop()
                                          infinite loop
        kdump_nmi_shootdown_cpus()
          issue NMI IPI -----------> blocked until IRET
                                          infinite loop...

Here, since CPU 1 is in NMI context, the second NMI from CPU 0 is
blocked until CPU 1 executes IRET. However, CPU 1 never executes IRET,
so the NMI is not handled and the callback function to save registers is
never called.

In practice, this can happen on some servers which broadcast NMIs to all
CPUs when the NMI button is pushed.

To save registers in this case, we need to:

  a) Return from NMI handler instead of looping infinitely
  or
  b) Call the callback function directly from the infinite loop

Inherently, a) is risky because NMI is also used to prevent corrupted
data from being propagated to devices.  So, we chose b).

This patch does the following:

1. Move the infinite looping of CPUs which haven't called panic() in NMI
   context (actually done by panic_smp_self_stop()) outside of panic() to
   enable us to refer pt_regs. Please note that panic_smp_self_stop() is
   still used for normal context.

2. Call a callback of kdump_nmi_shootdown_cpus() directly to save
   registers and do some cleanups after setting waiting_for_crash_ipi which
   is used for counting down the number of CPUs which handled the callback
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Gobinda Charan Maji <gobinda.cemk07@gmail.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: lkml <linux-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/20151210014628.25437.75256.stgit@softrs


[ Cleanup comments, fixup formatting. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

There are two kexec load syscalls, kexec_load another and kexec_file_load.
 kexec_file_load has been splited as kernel/kexec_file.c.  In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled.  But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel.  KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig.  Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.or...

The ASRock Q1900DC-ITX mainboard (Baytrail-D) hangs randomly in
both BIOS and UEFI mode while rebooting unless reboot=pci is
used. Add a quirk to reboot via the pci method.

The problem is very intermittent and hard to debug, it might succeed
rebooting just fine 40 times in a row - but fails half a dozen times
the next day. It seems to be slightly less common in BIOS CSM mode
than native UEFI (with the CSM disabled), but it does happen in either
mode. Since I've started testing this patch in late january, rebooting
has been 100% reliable.

Most of the time it already hangs during POST, but occasionally it
might even make it through the bootloader and the kernel might even
start booting, but then hangs before the mode switch. The same symptoms
occur with grub-efi, gummiboot and grub-pc, just as well as (at least)
kernel 3.16-3.19 and 4.0-rc6 (I haven't tried older kernels than 3.16).
Upgrading to the most current mainboard firmware of the ASRock
Q1900DC-ITX, version 1.20, does not improve the situation.

( Searching the web seems to suggest that other Bay Trail-D mainboards
  might be affected as well. )
--
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: <stable@vger.kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150330224427.0fb58e42@mir

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Clean up code by moving IOAPIC related declarations from hw_irq.h into
io_apic.h.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Aubrey <aubrey.li@linux.intel.com>
Cc: Ryan Desfosses <ryan@desfo.org>
Cc: Quentin Lambert <lambert.quentin@gmail.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: http://lkml.kernel.org/r/1414397531-28254-14-git-send-email-jiang.liu@linux.intel.com

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

It appears that the BayTrail-T class of hardware requires EFI in order
to powerdown and reboot and no other reliable method exists.

This quirk is generally applicable to all hardware that has the ACPI
Hardware Reduced bit set, since usually ACPI would be the preferred
method.

Cc: Len Brown <len.brown@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Implement efi_reboot(), which is really just a wrapper around the
EfiResetSystem() EFI runtime service, but it does at least allow us to
funnel all callers through a single location.

It also simplifies the callsites since users no longer need to check to
see whether EFI_RUNTIME_SERVICES are enabled.

Cc: Tony Luck <tony.luck@intel.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Certec BPC600 needs reboot=pci to actually reboot.
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Li Aubrey <aubrey.li@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1399446114-2147-1-git-send-email-christian.gmeiner@gmail.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Steve reported a reboot hang and bisected it back to this commit:

  a4f1987e

 x86, reboot: Add EFI and CF9 reboot methods into the default list

He heroically tested all reboot methods and found the following:

  reboot=t       # triple fault                  ok
  reboot=k       # keyboard ctrl                 FAIL
  reboot=b       # BIOS                          ok
  reboot=a       # ACPI                          FAIL
  reboot=e       # EFI                           FAIL   [system has no EFI]
  reboot=p       # PCI 0xcf9                     FAIL

And I think it's pretty obvious that we should only try PCI 0xcf9 as a
last resort - if at all.

The other observation is that (on this box) we should never try
the PCI reboot method, but close with either the 'triple fault'
or the 'BIOS' (terminal!) reboot methods.

Thirdly, CF9_COND is a total misnomer - it should be something like
CF9_SAFE or CF9_CAREFUL, and 'CF9' should be 'CF9_FORCE' ...

So this patch fixes the worst problems:

 - it orders the actual reboot logic to follow the reboot ordering
   pattern - it was in a pretty random order before for no good
   reason.

 - it fixes the CF9 misnomers and uses BOOT_CF9_FORCE and
   BOOT_CF9_SAFE flags to make the code more obvious.

 - it tries the BIOS reboot method before the PCI reboot method.
   (Since 'BIOS' is a terminal reboot method resulting in a hang
    if it does not work, this is essentially equivalent to removing
    the PCI reboot method from the default reboot chain.)

 - just for the miraculous possibility of terminal (resulting
   in hang) reboot methods of triple fault or BIOS returning
   without having done their job, there's an ordering between
   them as well.
Reported-and-bisected-and-tested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Aubrey <aubrey.li@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Link: http://lkml.kernel.org/r/20140404064120.GB11877@gmail.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Only CF9_COND is appropriate for inclusion in the default chain, not
CF9; the latter will poke that register unconditionally, whereas
CF9_COND will at least look for PCI configuration method #1 or #2
first (a weak check, but better than nothing.)

CF9 should be used for explicit system configuration (command line or
DMI) only.

Cc: Aubrey Li <aubrey.li@intel.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Link: http://lkml.kernel.org/r/53130A46.1010801@linux.intel.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Reboot is the last service linux OS provides to the end user. We are
supposed to make this function more robust than today. This patch adds
all of the known reboot methods into the default attempt list. The
machines requiring reboot=efi or reboot=p or reboot=bios get a chance
to reboot automatically now.

If there is a new reboot method emerged, we are supposed to add it to
the default list as well, instead of adding the endless dmidecode entry.

If one method required is in the default list in this patch but the
machine reboot still hangs, that means some methods ahead of the
required method cause the system hangs, then reboot the machine by
passing reboot= arguments and submit the reboot dmidecode table quirk.

We are supposed to remove the reboot dmidecode table from the kernel,
but to be safe, we keep it. This patch prevents us from adding more.
If you happened to have a machine listed in the reboot dmidecode
table and this patch makes reboot work on your machine, please submit
a patch to remove the quirk.

The default reboot order with this patch is now:

    ACPI > KBD > ACPI > KBD > EFI > CF9_COND > BIOS

Because BIOS and TRIPLE are mutually exclusive (either will either
work or hang the machine) that method is not included.

[ hpa: as with any changes to the reboot order, this patch will have
  to be monitored carefully for regressions. ]
Signed-off-by: Aubrey Li <aubrey.li@intel.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Link: http://lkml.kernel.org/r/53130A46.1010801@linux.intel.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Since erratum AVR31 in "Intel Atom Processor C2000 Product Family
Specification Update" is now published, I added a justification
comment for disabling IO APIC before Local APIC, as changed in commit:

522e6646

 x86/apic: Disable I/O APIC before shutdown of the local APIC
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1386202069-51515-1-git-send-email-fenghua.yu@intel.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

In reboot and crash path, when we shut down the local APIC, the I/O APIC is
still active. This may cause issues because external interrupts
can still come in and disturb the local APIC during shutdown process.

To quiet external interrupts, disable I/O APIC before shutdown local APIC.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1382578212-4677-1-git-send-email-fenghua.yu@intel.com


Cc: <stable@kernel.org>
[ I suppose the 'issue' is a hang during shutdown. It's a fine change nevertheless. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

commit:

  c767a54b

 x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>

broke the log messages in the set_bios/pci/kbd_reboot() functions, by
putting the reboot method string and quirk entry's ident string in the
wrong order. This patch fixes it.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Cc: holt@sgi.com
Cc: davej@fedoraproject.org
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: awilliam@redhat.com
Link: http://lkml.kernel.org/r/1382598693-29334-1-git-send-email-tianyu.lan@intel.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Dell Latitude E5410 needs reboot=pci to actually reboot.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://lkml.kernel.org/r/1380888964-14517-1-git-send-email-ville.syrjala@linux.intel.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Grouping them by vendor should make it easier to spot duplicates.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20131001203655.GA10719@redhat.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Two entries for the same system type were added, with two different vendor
names: 'Dell' and 'Dell, Inc.'.

Since a prefix match is being used by the DMI parsing code, we can eliminate
the latter as redundant.
Reported-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Masoud Sharbiani <msharbiani@twitter.com>
Cc: holt@sgi.com
Link: http://lkml.kernel.org/r/1380216643-4683-1-git-send-email-masoud.sharbiani@gmail.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

In current implementation for reboot type CF9 and CF9_COND,
warm and cold reset are not differentiated, and both are
performed by writing 0x06 to port 0xCF9.

This commit will differentiate warm and cold reset:

For warm reset, write 0x06 to port 0xCF9;
For cold reset, write 0x0E to port 0xCF9.

[ hpa: This meaning of "cold" and "warm" reset is different from other
  reboot types use, where "warm" means "bypass BIOS POST".  It is also
  not entirely clear that it actually solves any actual problem.  However,
  it would seem fairly harmless to offer this additional option.

  Also note that we do not mask bit 3 in the "warm reset" case.  This
  preserves the behavior on existing systems, including ones quirked
  to use CF9.  It seems reasonable that on any system where the
  warm/cold distinction actually matters that bit 3 would be read as
  zero. ]

From: Liu Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Li Fei <fei.li@intel.com>
Link: http://lkml.kernel.org/r/1377072837.24556.2.camel@fli24-HP-Compaq-8100-Elite-CMT-PC

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This seems to have been copied from the Optiplex 990 entry
above, but somoene forgot to change the ident text.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20130925001344.GA13554@redhat.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Dell PowerEdge C6100 machines fail to completely reboot about 20% of the time.
Signed-off-by: Masoud Sharbiani <msharbiani@twitter.com>
Signed-off-by: Vinson Lee <vlee@twitter.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1379717947-18042-1-git-send-email-vlee@freedesktop.org

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge together the unicore32, arm, and x86 reboot= command line
parameter handling.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Prepare for the moving the parsing of reboot= to the generic kernel code
by making reboot_mode into a more generic form.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Miguel Boton <mboton.lkml@gmail.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Originally 'efi_enabled' indicated whether a kernel was booted from
EFI firmware. Over time its semantics have changed, and it now
indicates whether or not we are booted on an EFI machine with
bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.

The immediate motivation for this patch is the bug report at,

    https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557

which details how running a platform driver on an EFI machine that is
designed to run under BIOS can cause the machine to become
bricked. Also, the following report,

    https://bugzilla.kernel.org/show_bug.cgi?id=47121



details how running said driver can also cause Machine Check
Exceptions. Drivers need a new means of detecting whether they're
running on an EFI machine, as sadly the expression,

    if (!efi_enabled)

hasn't been a sufficient condition for quite some time.

Users actually want to query 'efi_enabled' for different reasons -
what they really want access to is the list of available EFI
facilities.

For instance, the x86 reboot code needs to know whether it can invoke
the ResetSystem() function provided by the EFI runtime services, while
the ACPI OSL code wants to know whether the EFI config tables were
mapped successfully. There are also checks in some of the platform
driver code to simply see if they're running on an EFI machine (which
would make it a bad idea to do BIOS-y things).

This patch is a prereq for the samsung-laptop fix patch.

Cc: David Airlie <airlied@linux.ie>
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Peter Jones <pjones@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Steve Langasek <steve.langasek@canonical.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Remove the quirk for the SBC FITPC. It seems ot have been
required when the default was kbd reboot, but no longer required
now that the default is acpi reboot. Furthermore, BIOS reboot no
longer works for this board as of 2.6.39 or any of the 3.x
kernels.
Signed-off-by: David Hooper <dave@beermex.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/20121002142635.17403.59959.stgit@localhost.localdomain

Signed-off-by: Ingo Molnar <mingo@kernel.org>

We write reboot_mode to BIOS location 0x472 in
native_machine_emergency_restart() (reboot.c:542) already, there is no
need to then write it again in machine_real_restart().

This means nothing gets written there for MRR_APM, but the APM call is
a poweroff call and doesn't use this memory location.

Link: http://lkml.kernel.org/n/tip-3i0pfh44c1e3jv5lab0cf7sc@git.kernel.org

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

With the revamped realmode trampoline code, it is trivial to extend
support for reboot=bios to x86-64.  Furthermore, while we are at it,
remove the restriction that only we can only override the reboot CPU
on 32 bits.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-jopx7y6g6dbcx4tpal8q0jlr@git.kernel.org

When rebooting our 24 CPU Westmere servers with 3.4-rc6, we
always see this warning msg:

Restarting system.
machine restart
------------[ cut here ]------------
WARNING: at arch/x86/kernel/smp.c:125
native_smp_send_reschedule+0x74/0xa7() Hardware name: X8DTN
Modules linked in: igb [last unloaded: scsi_wait_scan]
Pid: 1, comm: systemd-shutdow Not tainted 3.4.0-rc6+ #22
Call Trace:
 <IRQ>  [<ffffffff8102a41f>] warn_slowpath_common+0x7e/0x96
 [<ffffffff8102a44c>] warn_slowpath_null+0x15/0x17
 [<ffffffff81018cf7>] native_smp_send_reschedule+0x74/0xa7
 [<ffffffff810561c1>] trigger_load_balance+0x279/0x2a6
 [<ffffffff81050112>] scheduler_tick+0xe0/0xe9
 [<ffffffff81036768>] update_process_times+0x60/0x70
 [<ffffffff81062f2f>] tick_sched_timer+0x68/0x92
 [<ffffffff81046e33>] __run_hrtimer+0xb3/0x13c
 [<ffffffff81062ec7>] ? tick_nohz_handler+0xd0/0xd0
 [<ffffffff810474f2>] hrtimer_interrupt+0xdb/0x198
 [<ffffffff81019a35>] smp_apic_timer_interrupt+0x81/0x94
 [<ffffffff81655187>] apic_timer_interrupt+0x67/0x70
 <EOI>  [<ffffffff8101a3c4>] ? default_send_IPI_mask_allbutself_phys+0xb4/0xc4
 [<ffffffff8101c680>] physflat_send_IPI_allbutself+0x12/0x14
 [<ffffffff81018db4>] native_nmi_stop_other_cpus+0x8a/0xd6
 [<ffffffff810188ba>] native_machine_shutdown+0x50/0x67
 [<ffffffff81018926>] machine_shutdown+0xa/0xc
 [<ffffffff8101897e>] native_machine_restart+0x20/0x32
 [<ffffffff810189b0>] machine_restart+0xa/0xc
 [<ffffffff8103b196>] kernel_restart+0x47/0x4c
 [<ffffffff8103b2e6>] sys_reboot+0x13e/0x17c
 [<ffffffff8164e436>] ? _raw_spin_unlock_bh+0x10/0x12
 [<ffffffff810fcac9>] ? bdi_queue_work+0xcf/0xd8
 [<ffffffff810fe82f>] ? __bdi_start_writeback+0xae/0xb7
 [<ffffffff810e0d64>] ? iterate_supers+0xa3/0xb7
 [<ffffffff816547a2>] system_call_fastpath+0x16/0x1b
---[ end trace 320af5cb1cb60c5b ]---

The root cause seems to be the
default_send_IPI_mask_allbutself_phys() takes quite some time (I
measured it could be several ms) to complete sending NMIs to all
the other 23 CPUs, and for HZ=250/1000 system, the time is long
enough for a timer interrupt to happen, which will in turn
trigger to kick load balance to a stopped CPU and cause this
warning in native_smp_send_reschedule().

So disabling the local irq before stop_other_cpu() can fix this
problem (tested 25 times reboot ok), and it is fine as there
should be nobody caring the timer interrupt in such reboot
stage.

The latest 3.4 kernel slightly changes this behavior by sending
REBOOT_VECTOR first and only send NMI_VECTOR if the REBOOT_VCTOR
fails, and this patch is still needed to prevent the problem.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120530231541.4c13433a@feng-i7

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Use a more current logging style:

 - Bare printks should have a KERN_<LEVEL> for consistency's sake
 - Add pr_fmt where appropriate
 - Neaten some macro definitions
 - Convert some Ok output to OK
 - Use "%s: ", __func__ in pr_fmt for summit
 - Convert some printks to pr_<level>

Message output is not identical in all cases.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: levinsasha928@gmail.com
Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop


[ merged two similar patches, tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Dell Precision M6600 is known to require PCI reboot, so add it to
the reboot blacklist in pci_reboot_dmi_table[].

https://bugzilla.kernel.org/show_bug.cgi?id=42749



cc: x86@kernel.org
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Replaced copying of real_mode_header with a pointer
to beginning of RM memory.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-19-git-send-email-jarkko.sakkinen@intel.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Migrated reboot_32.S from x86_trampoline to the real-mode
blob.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-5-git-send-email-jarkko.sakkinen@intel.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

This commit simply cleans up the style used in this file to fall
in line with what's specified in CodingStyle.  Mostly comment
changes, with a single removal of unneeded braces.

Note that the comments for all the DMI quirks in
reboot_dmi_table now all line up consistently using tabs instead
of spaces.
Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Link: http://lkml.kernel.org/n/tip-lde9yy7qsomh0sdqevn7xp56@git.kernel.org


[ Fixed a few small details. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This commit reduces the X86_32 reboot_dmi_table and the X86_64
pci_reboot_dmi_table into a single table with a single set of
functions (e.g., only 1 call to core_initcall).

The table entries that use set_bios_reboot are grouped together
inside a #define CONFIG_X86_32 block.

Note that there's a single entry that uses set_kbd_reboot, which
used to be available only on X86_32.  This commit moves that
entry outside the X86_32 block because it seems it never should
have been in there.  There's multiple places in reboot.c that
assume KBD is valid regardless of X86_32/X86_64.
Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Link: http://lkml.kernel.org/n/tip-lv3aliubas2l3aenq8v3uklk@git.kernel.org

Signed-off-by: Ingo Molnar <mingo@elte.hu>

This commit removes the reboot quirk originally added by commit
e19e074b ("x86: Fix reboot problem on VersaLogic Menlow boards").

Testing with a VersaLogic Ocelot (VL-EPMs-21a rev 1.00 w/ BIOS
6.5.102) revealed the following regarding the reboot hang
problem:

- v2.6.37 reboot=bios was needed.

- v2.6.38-rc1: behavior changed, reboot=acpi is needed,
  reboot=kbd and reboot=bios results in system hang.

- v2.6.38: VersaLogic patch (e19e074b "x86: Fix reboot problem on
  VersaLogic Menlow boards") was applied prior to v2.6.38-rc7.  This
  patch sets a quirk for VersaLogic Menlow boards that forces the use
  of reboot=bios, which doesn't work anymore.

- v3.2: It seems that commit 660e34ce ("x86: Reorder reboot method
  preferences") changed the default reboot method to acpi prior to
  v3.0-rc1, which means the default behavior is appropriate for the
  Ocelot.  No VersaLogic quirk is required.

The Ocelot board used for testing can successfully reboot w/out
hav...

Skip DMI checks for vendor specific reboot quirks if the user
passed in a reboot= arg on the command line - we should never
override user choices.
Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Michael D Labriola <mlabriol@gdeb.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/87wr8ab9od.fsf@gmail.com

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Looks like on some Acer Aspire 1s with older bioses, reboot via bios
fails.  It works on my machine, (with BIOS version 0.3310) but
not on some others (BIOS version 0.3309).

There's a log of problems at:

  https://bbs.archlinux.org/viewtopic.php?id=124136



This patch adds a different callback to the reboot quirk table,
to allow rebooting via keybaord controller.
Reported-by: Uroš Vampl <mobile.leecher@gmail.com>
Tested-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1323093233-9481-1-git-send-email-anarsoul@gmail.com

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Dell OptiPlex 990 is known to require PCI reboot, so add it to
the reboot blacklist in pci_reboot_dmi_table[].
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Link: http://lkml.kernel.org/r/201111160019.51303.rjw@sisk.pl

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Just convert all the files that have an nmi handler to the new routines.
Most of it is straight forward conversion.  A couple of places needed some
tweaking like kgdb which separates the debug notifier from the nmi handler
and mce removes a call to notify_die.

[Thanks to Ying for finding out the history behind that mce call

https://lkml.org/lkml/2010/5/27/114

And Boris responding that he would like to remove that call because of it

https://lkml.org/lkml/2011/9/21/163

]

The things that get converted are the registeration/unregistration routines
and the nmi handler itself has its args changed along with code removal
to check which list it is on (most are on one NMI list except for kgdb
which has both an NMI routine and an NMI Unknown routine).
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Corey Minyard <minyard@acm.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <ak@linux.i...

Yet another variant of the Dell Latitude series which requires
reboot=pci.

From the E5420 bug report by Daniel J Blueman:

> The E6420 is affected also (same platform, different casing and
> features), which provides an external confirmation of the issue; I can
> submit a patch for that later or include it if you prefer:
> http://linux.koolsolutions.com/2009/08/04/howto-fix-linux-hangfreeze-during-reboots-and-restarts/

Reported-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>

Rebooting on the Dell E5420 often hangs with the keyboard or ACPI
methods, but is reliable via the PCI method.

[ hpa: this was deferred because we believed for a long time that the
  recent reshuffling of the boot priorities in commit
  660e34ce

 fixed this platform.
  Unfortunately that turned out to be incorrect. ]
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Link: http://lkml.kernel.org/r/1305248699-2347-1-git-send-email-daniel.blueman@gmail.com

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>