Setting monarch_cpu = -1 to let slaves frozen might not work, because
there might be slaves being late, not entered the rendezvous yet.
Such slaves might be caught in while (monarch_cpu == -1) loop.

Use kdump_in_progress instead of monarch_cpus to break INIT rendezvous
and let all slaves enter DIE_INIT_SLAVE_LEAVE smoothly.

And monarch no longer need to manage rendezvous if once kdump_in_progress
is set, catch the monarch in DIE_INIT_MONARCH_ENTER then.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

kdump_on_init

CPUs should be frozen if possible, otherwise it might hinder kdump.
So if there are CPUs not respond to IPI, try INIT to stop them.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Summary:

  Asserting INIT might block kdump if the system is already going to
  start kdump via panic.

Description:

  INIT can interrupt anywhere in panic path, so it can interrupt in
  middle of kdump kicked by panic.  Therefore there is a race if kdump
  is kicked concurrently, via Panic and via INIT.

  INIT could fail to invoke kdump if the system is already going to
  start kdump via panic.  It could not restart kdump from INIT handler
  if some of cpus are already playing dead with INIT masked.  It also
  means that INIT could block kdump's progress if no monarch is entered
  in the INIT rendezvous.

  Panic+INIT is a rare, but possible situation since it can be assumed
  that the kernel or an internal agent decides to panic the unstable
  system while another external agent decides to send an INIT to the
  system at same time.

How to reproduce:

  Assert INIT just after panic, before all other cpus have frozen

Expected results:

  continue kdump invoked by panic, or restart kdump from INIT

Actual results:

  might be hang, crashdump not retrieved

Proposed Fix:

  This patch masks INIT first in panic path to take the initiative on
  kdump, and reuse atomic value kdump_in_progress to make sure there is
  only one initiator of kdump.  All INITs asserted later should be used
  only for freezing all other cpus.

  This mask will be removed soon by rfi in relocate_kernel.S, before jump
  into kdump kernel, after all cpus are frozen and no-op INIT handler is
  registered.  So if INIT was in the interval while it is masked, it will
  pend on the system and will received just after the rfi, and handled by
  the no-op handler.

  If there was a MCA event while psr.mc is 1, in theory the event will
  pend on the system and will received just after the rfi same as above.
  MCA handler is unregistered here at the time, so received MCA will not
  reach to OS_MCA and will result in warmboot by SAL.

  Note that codes in this masked interval are relatively simpler than
  that in MCA/INIT handler which also executed with the mask.  So it can
  be said that probability of error in this interval is supposed not so
  higher than that in MCA/INIT handler.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Summary:

  Asserting INIT on cpu going to be offline will result in unexpected
  behavior.  It will be a real problem in kdump cases where INIT might
  be asserted to unstable APs going to be offline by returning to SAL.

Description:

  Since psr.mc is cleared when bits in psr are set to SAL_PSR_BITS_TO_SET
  in ia64_jump_to_sal(), there is a small window (~few msecs) that the
  cpu can receive INIT even if the cpu enter there via INIT handler.
  In this window we do restore of registers for SAL, so INIT asserted
  here will not work properly.

  It is hard to remove this window by masking INIT (i.e. setting psr.mc)
  because we have to unmask it later in OS, because we have to use branch
  instruction (br.ret, not rfi) to return SAL, due to OS_BOOT_RENDEZ to
  SAL return convention.

  I suppose this window will not be a real problem on cpu offline if we
  can educate people not to push INIT button during hotplug operation.
  However, only exception is a race in kdump and INIT.  Now kdump returns
  APs to SAL before processing dump, but the kernel might receive INIT at
  that point in time.  Such INIT might be asserted by kdump itself if an
  AP doesn't react IPI soon and kdump decided to use INIT to stop the AP.
  Or it might be asserted by operator or an external agent to start dump
  on the unstable system.

  Such panic+INIT or INIT+INIT cases should be rare, but it will be happy
  if we can retrieve crashdump even in such cases.

How to reproduce:

  panic+INIT or INIT+INIT, with kdump configured

Expected results:

  crashdump is retrieved anyway

Actual results:

  panic, hang etc. (unexpected)

Proposed fix

  To avoid the window on the way to SAL, this patch stops returning APs
  to SAL in case of kdump.  In other words, this patch makes APs spin
  in OS instead of spinning in SAL.

  (* Note: What impact would be there?  If a cpu is spinning in SAL,
   the cpu is in BOOT_RENDEZ loop, as same as offlined cpu.
   In theory if an INIT is asserted there, cpus in the BOOT_RENDEZ loop
   should not invoke OS_INIT on it.  So in either way, no matter where
   the cpu is spinning actually in, once cpu starts spin and act as
   "frozen," INIT on the cpu have no effects.
   From another point of view, all debug information on the cpu should
   have stored to memory before the cpu start to be frozen.  So no more
   action on the cpu is required.)

  I confirmed that the kdump sometime hangs by concurrent INITs (another
  INIT after an INIT), and it doesn't hang after applying this patch.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Summary:

  INIT asserted on kdump kernel invokes INIT handler not only on a
  cpu that running on the kdump kernel, but also BSP of the panicked
  kernel, because the (badly) frozen BSP can be thawed by INIT.

Description:

  The kdump_cpu_freeze() is called on cpus except one that initiates
  panic and/or kdump, to stop/offline the cpu (on ia64, it means we
  pass control of cpus to SAL, or put them in spinloop).  Note that
  CPU0(BSP) always go to spinloop, so if panic was happened on an AP,
  there are at least 2cpus (= the AP and BSP) which not back to SAL.

  On the spinning cpus, interrupts are disabled (rsm psr.i), but INIT
  is still interruptible because psr.mc for mask them is not set unless
  kdump_cpu_freeze() is not called from MCA/INIT context.

  Therefore, assume that a panic was happened on an AP, kdump was
  invoked, new INIT handlers for kdump kernel was registered and then
  an INIT is asserted.  From the viewpoint of SAL, there are 2 online
  cpus, so INIT will be delivered to both of them.  It likely means
  that not only the AP (= a cpu executing kdump) enters INIT handler
  which is newly registered, but also BSP (= another cpu spinning in
  panicked kernel) enters the same INIT handler.  Of course setting of
  registers in BSP are still old (for panicked kernel), so what happen
  with running handler with wrong setting will be extremely unexpected.
  I believe this is not desirable behavior.

How to Reproduce:

  Start kdump on one of APs (e.g. cpu1)
    # taskset 0x2 echo c > /proc/sysrq-trigger
  Then assert INIT after kdump kernel is booted, after new INIT handler
  for kdump kernel is registered.

Expected results:

  An INIT handler is invoked only on the AP.

Actual results:

  An INIT handler is invoked on the AP and BSP.

Sample of results:

  I got following console log by asserting INIT after prompt "root:/>".
  It seems that two monarchs appeared by one INIT, and one panicked at
  last.  And it also seems that the panicked one supposed there were
  4 online cpus and no one did rendezvous:

    :
    [  0 %]dropping to initramfs shell
    exiting this shell will reboot your system
    root:/> Entered OS INIT handler. PSP=fff301a0 cpu=0 monarch=0
    ia64_init_handler: Promoting cpu 0 to monarch.
    Delaying for 5 seconds...
    All OS INIT slaves have reached rendezvous
    Processes interrupted by INIT - 0 (cpu 0 task 0xa000000100af0000)
    :
    <<snip>>
    :
    Entered OS INIT handler. PSP=fff301a0 cpu=0 monarch=1
    Delaying for 5 seconds...
    mlogbuf_finish: printing switched to urgent mode, MCA/INIT might be dodgy or fail.
    OS INIT slave did not rendezvous on cpu 1 2 3
    INIT swapper 0[0]: bugcheck! 0 [1]
    :
    <<snip>>
    :
    Kernel panic - not syncing: Attempted to kill the idle task!

Proposed fix:

  To avoid this problem, this patch inserts ia64_set_psr_mc() to mask
  INIT on cpus going to be frozen.  This masking have no effect if the
  kdump_cpu_freeze() is called from INIT handler when kdump_on_init == 1,
  because psr.mc is already turned on to 1 before entering OS_INIT.
  I confirmed that weird log like above are disappeared after applying
  this patch.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

There are many notify_die() and almost all take same style with
ia64_mca_spin().  This patch defines macros and replace them all,
to reduce lines and to improve readability.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

This patch fixes the problem that kdump by INIT does not work if we use
makedumpfile. The problem is that after INIT is issued, 2nd kernel
starts and makedumpfile fails with the following error message.

/proc/vmcore doesn't contain vmcoreinfo.
'-x' or '-i' must be specified.

makedumpfile Failed.

The cause of this problem is that kernel does not call
crash_save_vmcoreinfo. When kdump starts by panic or sysrq-trigger,
crash_save_vmcoreinfo is called by crash_kexec. But this function is not
called when kdump starts by INIT. The Attached patch fixes this.

This patch just adds crash_save_vmcoreinfo into machine_kdump_on_init so
that crash_save_vmcoreinfo can be called when kdump starts by INIT.
I tested this patch with linux-2.6.25-rc9 and I confirmed it worked.
Signed-off-by: NTakao Indoh <indou.takao@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Fix indenting of switch statement to follow Documentation/CodingStyle.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

While it is convenient that we can invoke kdump by asserting INIT
via button on chassis etc., there are some situations that invoking
kdump on fatal MCA is not welcomed rather than rebooting fast without
dump.

This patch adds a new flag 'kdump_on_fatal_mca' that is independent
from 'kdump_on_init' currently available.  Adding this flag enable
us to turning on/off of kdump depend on the event, INIT and/or fatal
MCA.  Default for this flag is to take the dump.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

__FUNCTION__ is gcc-specific, use __func__

Long lines have been kept where they exist, some small spacing changes
have been done.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Fix the problem that kdump on INIT hung up if kdump kernel image is
not configured.

The kdump_init_notifier() on monarch CPU stops its operation at
DIE_INIT_MONARCH_LEAVE time if the kdump kernel image is not
configured. On the other hand, kdump_init_notifier() on non-monarch
CPUs get into spin because they don't know the fact the monarch stops
its operation. This is the cause of this problem. To fix this problem,
we need to check the kdump kernel image at the top of the
kdump_init_notifier() function.
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Fix the problem that kdump on INIT causes a kernel panic if kdump
kernel image is not configured. The cause of this problem is
machine_kexec_on_init() is using printk in INIT context. It should
use ia64_mca_printk() instead.
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The current implementation of kdump on INIT events would enter
kdump processing on DIE_INIT_MONARCH_ENTER and DIE_INIT_SLAVE_ENTER
events. Thus, the monarch cpu would go ahead and boot up the kdump

On SN shub2 systems, this out-of-sync situation causes some slave
cpus on different nodes to enter POD.

This patch moves kdump entry points to DIE_INIT_MONARCH_LEAVE and
DIE_INIT_SLAVE_LEAVE. It also sets kdump_in_progress variable in
the DIE_INIT_MONARCH_PROCESS event to not dump all active stack
traces to the console in the case of kdump.

I have tested this patch on an SN machine and a HP RX2600.
Signed-off-by: NJay Lan <jlan@sgi.com>
Acked-by: NZou Nan hai <nanhai.zou@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Spelling and apostrophe fixes in arch/ia64/.
Signed-off-by: NSimon Arlott <simon@fire.lp0.eu>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Currently the size of the per-cpu region reserved to save crash notes is
set by the per-architecture value MAX_NOTE_BYTES.  Which in turn is
currently set to 1024 on all supported architectures.

While testing ia64 I recently discovered that this value is in fact too
small.  The particular setup I was using actually needs 1172 bytes.  This
lead to very tedious failure mode where the tail of one elf note would
overwrite the head of another if they ended up being alocated sequentially
by kmalloc, which was often the case.

It seems to me that a far better approach is to caclculate the size that
the area needs to be.  This patch does just that.

If a simpler stop-gap patch for ia64 to be squeezed into 2.6.21(.X) is
needed then this should be as easy as making MAX_NOTE_BYTES larger in
arch/asm-ia64/kexec.h.  Perhaps 2048 would be a good choice.  However, I
think that the approach in this patch is a much more robust idea.
Acked-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch moves the die notifier handling to common code.  Previous
various architectures had exactly the same code for it.  Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)

arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at.  avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NBryan Wu <bryan.wu@analog.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clearly should be checking for "val == DIE_INIT_SLAVE_ENTER".
Signed-off-by: NJay Lan <jlan@sgi.com>
Acked-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Grammatical fixes (s/freezed/frozen/)
Make some variables static
Change a C++ "//" comment to "/* ... */"
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name.  Which is
pain for caching and the proc interface never implemented.

I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.

So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixes a NULL-pointer dereference in ia64_machine_kexec().

The variable ia64_kimage is set in machine_kexec_prepare() which is
called from sys_kexec_load(). If kdump wasn't configured before,
ia64_kimage is NULL.  machine_kdump_on_init() passes ia64_kimage() to
machine_kexec() which assumes a valid value.

The patch also adds a few sanity checks for the image to simplify
debugging of similar problems in future.
Signed-off-by: NBernhard Walle <bwalle@suse.de>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Kexec support for 2.6.20 on ia64 does not build properly using a config
made up by CONFIG_SMP=n and CONFIG_HOTPLUG_CPU=n:
Signed-off-by: NMagnus Damm <magnus@valinux.co.jp>
Acked-by: NSimon Horman <horms@verge.net.au>
Acked-by: NJay Lan <jlan@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Actually, on reflection I think that there is a good case for
keeping the options separate. I am thinking particularly of people
who want a very small crashdump kernel and thus don't want to compile
in kexec.

The patch below should fix things up so that all valid combinations of
KEXEC, CRASH_DUMP and VMCORE compile cleanly - VMCORE depends on
CRASH_DUMP which is why I said valid combinations. In a nutshell
it just untangles unrelated code and switches around a few defines.

Please note that it creats a new file, arch/ia64/kernel/crash_dump.c
This is in keeping with the i386 implementation.
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Changes and updates.

1. Remove fake rendz path and related code according to discuss with Khalid Aziz.
2. fc.i offset fix in relocate_kernel.S.
3. iospic shutdown code eoi and mask race fix from Fujitsu.
4. Warm boot hook in machine_kexec to SN SAL code from Jack Steiner.
5. Send slave to SAL slave loop patch from Jay Lan.
6. Kdump on non-recoverable MCA event patch from Jay Lan
7. Use CTL_UNNUMBERED in kdump_on_init sysctl.
Signed-off-by: NZou Nan hai <nanhai.zou@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>