This patch introduces 4-level page tables to ia64.  I have run
some benchmarks and found nothing interesting.  Performance has
consistently fallen within the noise range.

It also introduces a config option (setting the default to 3
levels).  The config option prevents having 4 level page
tables with 64k base page size.
Signed-off-by: NRobin Holt <holt@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

XPC (as in arch/ia64/sn/kernel/xp*) has a need to notify other partitions
(SGI Altix) whenever a partition is going down in order to get them to
disengage from accessing the halting partition's memory. If this is not
done before the reset of the hardware, the other partitions can find
themselves encountering MCAs that bring them down.
Signed-off-by: NDean Nelson <dcn@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Conversion from kcalloc(1, to kzalloc.
Signed-off-by: NPanagiotis Issaris <takis@issaris.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid.  Improves efficiency of
resched_task and some cpu_idle routines.

* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
  and as we hold it during resched_task, then there is no need for an
  atomic test and set there. The only other time this should be set is
  when the task's quantum expires, in the timer interrupt - this is
  protected against because the rq lock is irq-safe.

- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
  won't get unset until the task get's schedule()d off.

- If we are running on the same CPU as the task we resched, then set
  TIF_NEED_RESCHED and no further action is required.

- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
  after TIF_NEED_RESCHED has been set, then we need to send an IPI.

Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.

* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
  becomes true, explicitly call schedule(). This makes things a bit clearer
  (IMO), but haven't updated all architectures yet.

- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
  to the resched_task rules, this isn't needed (and actually breaks the
  assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
  held). So remove that. Generally one less locked memory op when switching
  to the idle thread.

- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
  most polling idle loops. The above resched_task semantics allow it to be
  set until before the last time need_resched() is checked before going into
  a halt requiring interrupt wakeup.

  Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
  can be always left set, completely eliminating resched IPIs when rescheduling
  the idle task.

  POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Run idle threads with preempt disabled.

Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?

Might fix the CPU hotplugging hang which Nigel Cunningham noted.

We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.

After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep.  The CPU will continue executing
previous idle and have no chance to call play_dead.

By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.

From: alexs <ashepard@u.washington.edu>

  PPC build fix

From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>

  MIPS build fix
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NYoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some architectures define and use this type in their compat_ioctl code, but
all of them can easily use the identical ioctl_trans_handler_t type that is
defined in common code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ia64 translates normal loads and stores to special MMIO regions into I/O port
accesses.  Reserve these special MMIO regions in /proc/iomem.

Sample /proc/iomem:
    f8100000000-f81003fffff : PCI Bus 0000:80 I/O Ports 00000000-00000fff
    f8100400000-f81007fffff : PCI Bus 0000:8e I/O Ports 00001000-00001fff
    f8100800000-f8100ffffff : PCI Bus 0000:9c I/O Ports 00002000-00003fff
    f8101000000-f81017fffff : PCI Bus 0000:aa I/O Ports 00004000-00005fff

and corresponding /proc/ioports:
    00000000-00000fff : PCI Bus 0000:80
    00001000-00001fff : PCI Bus 0000:8e
    00002000-00003fff : PCI Bus 0000:9c
    00004000-00005fff : PCI Bus 0000:aa
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Fix a couple of altix interrupt related bugs.
Signed-off-by: NMark Maule <maule@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

When a page has a memory uncorrectable ECC error, the recovery
code wants to prevent the page from being reused.  This change
bumps the reference count to prevent the page from getting back
on the free list.

Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: NTony Luck <tony.luck@intel.com>

paddr needs to be shifted by PAGE_SHIFT to be valid
input for pfn_valid().
Signed-off-by: NRuss Anderson <rja@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The determination of whether an MCA is recoverable or not must
be based on the bits set in the PSP (Processor State Parameter).
The specific bits are shown in the Intel IA-64 Architecture Software
Developer's Manual, Vol 2, Table 11-6 Software Recovery Bits in
Processor State Parameter.  Those bits should be consistent
across the entire IA-64 family of processors.
Signed-off-by: NRuss Anderson <rja@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

At the moment, attempting to invoke a signal-handler on the normal
stack is guaranteed to fail if the stack-pointer happens not to be
16-byte aligned.  This is because the signal-trampoline will attempt
to store fp-regs with stf.spill instructions, which will trap for
misaligned addresses.  This isn't terribly useful behavior.  It's
better to just always align the signal frame to the next lower 16-byte
boundary.
Signed-off-by: NDavid Mosberger-Tang <David.Mosberger@acm.org>
Signed-off-by: NTony Luck <tony.luck@intel.com>

The original memory less node allocation attempted to use NODEDATA_ALIGN for
alignment.  The bootmem allocator only allows a power of two alignments. This
causes a BUG_ON for some nodes. For cpu only nodes just allocate with a
PERCPU_PAGE_SIZE alignment.

Some older firmware reports SLIT distances of 0xff and results in bestnode
not being computed. This is now treated correctly.

The failed allocation check was removed because it's redundant.  The
bootmem allocator already makes this check.

This fix has been boot tested on 4 node machine which has 4 cpu only nodes
and 1 memory node.  Thanks to Pete Keilty for reporting this and helping me
test it.
Signed-off-by: NBob Picco <bob.picco@hp.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

notify_die() added for MCA_{MONARCH,SLAVE,RENDEZVOUS}_{ENTER,PROCESS,LEAVE} and
INIT_{MONARCH,SLAVE}_{ENTER,PROCESS,LEAVE}.  We need multiple
notification points for these events because they can take many seconds
to run which has nasty effects on the behaviour of the rest of the
system.

DIE_SS replaced by a generic DIE_FAULT which checks the vector number,
to allow interception of faults other than SS.

DIE_MACHINE_{HALT,RESTART} added to allow last minute close down
processing, especially when the halt/restart routines are called from
error handlers.

DIE_OOPS added.

The check for kprobe's break numbers has been moved from traps.c to
kprobes.c, allowing DIE_BREAK to be used for any additional break
numbers, i.e. it is no longer kprobes specific.

Hooks for kernel debuggers and kernel dumpers added, ENTER and LEAVE.
Both of these disable the system for long periods which impact on
watchdogs and heartbeat systems in general.  More patches to come that
use these events to reset watchdogs and heartbeats.

unregister_die_notifier() added and both routines exported.  Requested
by Dean Nelson.

Lock removed from {un,}register_die_notifier.  notifier_chain_register()
already takes a lock.  Also the generic notifier chain locking is being
reworked to distinguish between callbacks that can block and those that
cannot, the lock in {un,}register_die_notifier would interfere with
that change.  http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2

Leading white space removed from arch/ia64/kernel/kprobes.c.

Typo in mca.c in original version of this patch found & fixed by Dean
Nelson.
Signed-off-by: NKeith Owens <kaos@sgi.com>
Acked-by: NDean Nelson <dcn@sgi.com>
Acked-by: NAnil Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

This is the arch/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in arch/.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NGrant Grundler <grundler@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use schedule_timeout_interruptible() instead of
set_current_state()/schedule_timeout() to reduce kernel size.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Reorganize the preempt_disable/enable calls to eliminate the extra preempt
depth.  Changes based on Paul McKenney's review suggestions for the kprobes
RCU changeset.
Signed-off-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Changes to the arch kprobes infrastructure to take advantage of the locking
changes introduced by usage of RCU for synchronization.  All handlers are now
run without any locks held, so they have to be re-entrant or provide their own
synchronization.
Signed-off-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

IA64 changes to track kprobe execution on a per-cpu basis.  We now track the
kprobe state machine independently on each cpu using an arch specific kprobe
control block.
Signed-off-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The following set of patches are aimed at improving kprobes scalability.  We
currently serialize kprobe registration, unregistration and handler execution
using a single spinlock - kprobe_lock.

With these changes, kprobe handlers can run without any locks held.  It also
allows for simultaneous kprobe handler executions on different processors as
we now track kprobe execution on a per processor basis.  It is now necessary
that the handlers be re-entrant since handlers can run concurrently on
multiple processors.

All changes have been tested on i386, ia64, ppc64 and x86_64, while sparc64
has been compile tested only.

The patches can be viewed as 3 logical chunks:

patch 1: 	Reorder preempt_(dis/en)able calls
patches 2-7: 	Introduce per_cpu data areas to track kprobe execution
patches 8-9: 	Use RCU to synchronize kprobe (un)registration and handler
		execution.

Thanks to Maneesh Soni, James Keniston and Anil Keshavamurthy for their
review and suggestions. Thanks again to Anil, Hien Nguyen and Kevin Stafford
for testing the patches.

This patch:

Reorder preempt_disable/enable() calls in arch kprobes files in preparation to
introduce locking changes.  No functional changes introduced by this patch.
Signed-off-by: NAnanth N Mavinakayahanalli <ananth@in.ibm.com>
Signed-off-by: NAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Andrew Morton suggested to move kprobes from kernel hacking menu, since
kernel hacking menu is in-appropriate for the Kprobes.  This patch moves
Kprobes and Oprofile under instrumentation menu.

(akpm: it's not a natural fit, but things like djprobes and the s390 guys'
statistics library need a home)
Signed-of-by: NPrasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: John Levon <levon@movementarian.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The current ia64 implementation of dma_get_cache_alignment does not work
for modules because it relies on a symbol which is not exported.  Direct
access to a global is a little ugly anyway, so this patch re-implements
dma_get_cache_alignment in a manner similar to what is currently used for
x86_64.
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Restrict CONFIG_SGI_SN_XP to IA64_GENERIC or IA64_SGI_SN2 kernels.
Signed-off-by: NDean Nelson <dcn@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

wrap_mmu_context(), delayed_tlb_flush(), get_mmu_context() all
have an extra { } block which cause one extra indentation.
get_mmu_context() is particularly bad with 5 indentations to
the most inner "if".  It finally gets on my nerve that I can't
keep the code within 80 columns.  Remove the extra { } block
and while I'm at it, reformat all the comments to 80-column
friendly.  No functional change at all with this patch.
Signed-off-by: NKen Chen <kenneth.w.chen@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Corrects the very inefficent method of finding free context_ids in
get_mmu_context().  Instead of walking the task_list of all processes,
2 bitmaps are used to efficently store and lookup state, inuse and
needs flushing. The entire rid address space is now used before calling
wrap_mmu_context and global tlb flushing.

Special thanks to Ken and Rohit for their review and modifications in
using a bit flushmap.
Signed-off-by: NPeter Keilty <peter.keilty@hp.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

I recently picked up my older work to remove unnecessary #includes of
sched.h, starting from a patch by Dave Jones to not include sched.h
from module.h. This reduces the number of indirect includes of sched.h
by ~300. Another ~400 pointless direct includes can be removed after
this disentangling (patch to follow later).
However, quite a few indirect includes need to be fixed up for this.

In order to feed the patches through -mm with as little disturbance as
possible, I've split out the fixes I accumulated up to now (complete for
i386 and x86_64, more archs to follow later) and post them before the real
patch.  This way this large part of the patch is kept simple with only
adding #includes, and all hunks are independent of each other.  So if any
hunk rejects or gets in the way of other patches, just drop it.  My scripts
will pick it up again in the next round.
Signed-off-by: NTim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Define jiffies_64 in kernel/timer.c rather than having 24 duplicated
defines in each architecture.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make sure we always return, as all syscalls should.  Also move the common
prototype to <linux/syscalls.h>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

pgdat->node_size_lock is basically only neeeded in one place in the normal
code: show_mem(), which is the arch-specific sysrq-m printing function.

Strictly speaking, the architectures not doing memory hotplug do no need this
locking in show_mem().  However, they are all included for completeness.  This
should also make any future consolidation of all of the implementations a
little more straightforward.

This lock is also held in the sparsemem code during a memory removal, as
sections are invalidated.  This is the place there pfn_valid() is made false
for a memory area that's being removed.  The lock is only required when doing
pfn_valid() operations on memory which the user does not already have a
reference on the page, such as in show_mem().
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There was one small but very significant change in the previous patch:
mprotect's flush_tlb_range fell outside the page_table_lock: as it is in 2.4,
but that doesn't prove it safe in 2.6.

On some architectures flush_tlb_range comes to the same as flush_tlb_mm, which
has always been called from outside page_table_lock in dup_mmap, and is so
proved safe.  Others required a deeper audit: I could find no reliance on
page_table_lock in any; but in ia64 and parisc found some code which looks a
bit as if it might want preemption disabled.  That won't do any actual harm,
so pending a decision from the maintainers, disable preemption there.

Remove comments on page_table_lock from flush_tlb_mm, flush_tlb_range and
flush_tlb_page entries in cachetlb.txt: they were rather misleading (what
generic code does is different from what usually happens), the rules are now
changing, and it's not yet clear where we'll end up (will the generic
tlb_flush_mmu happen always under lock?  never under lock?  or sometimes under
and sometimes not?).
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

First step in pushing down the page_table_lock.  init_mm.page_table_lock has
been used throughout the architectures (usually for ioremap): not to serialize
kernel address space allocation (that's usually vmlist_lock), but because
pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it.

Reverse that: don't lock or unlock init_mm.page_table_lock in any of the
architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take
and drop it when allocating a new one, to check lest a racing task already
did.  Similarly no page_table_lock in vmalloc's map_vm_area.

Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle
user mms, which are converted only by a later patch, for now they have to lock
differently according to whether or not it's init_mm.

If sources get muddled, there's a danger that an arch source taking
init_mm.page_table_lock will be mixed with common source also taking it (or
neither take it).  So break the rules and make another change, which should
break the build for such a mismatch: remove the redundant mm arg from
pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13).

Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64
used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to
pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64
map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free
took page_table_lock for no good reason.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ia64 has expand_backing_store function for growing its Register Backing Store
vma upwards.  But more complete code for this purpose is found in the
CONFIG_STACK_GROWSUP part of mm/mmap.c.  Uglify its #ifdefs further to provide
expand_upwards for ia64 as well as expand_stack for parisc.

The Register Backing Store vma should be marked VM_ACCOUNT.  Implement the
intention of growing it only a page at a time, instead of passing an address
outside of the vma to handle_mm_fault, with unknown consequences.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The original vm_stat_account has fallen into disuse, with only one user, and
only one user of vm_stat_unaccount.  It's easier to keep track if we convert
them all to __vm_stat_account, then free it from its __shackles.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

4ac0068f forgot to delete
the declaration of this variable which is no longer used.
Signed-off-by: NTony Luck <tony.luck@intel.com>

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

... and related annotations for amd64 - swiotlb code is shared, but
prototypes are not.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In arch/ia64/kernel/ptrace.c there is a test for a peek or poke of a
register image (in register backing storage).
The test can be unnecessarily long (and occurs while holding the tasklist_lock).
Especially long on a large system with thousands of active tasks.

The ptrace caller (presumably a debugger) specifies the pid of
its target and an address to peek or poke.  But the debugger could be
attached to several tasks.
The idea of find_thread_for_addr() is to find whether the target address
is in the RBS for any of those tasks.

Currently it searches the thread-list of the target pid.  If that search
does not find a match, and the shared mm-struct's user count indicates
that there are other tasks sharing this address space (a rare occurrence),
a search is made of all the tasks in the system.

Another approach can drastically shorten this procedure.
It depends upon the fact that in order to peek or poke from/to any task,
the debugger must first attach to that task.  And when it does, the
attached task is made a child of the debugger (is chained to its children list).

Therefore we can search just the debugger's children list.
Signed-off-by: NCliff Wickman <cpw@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

flush_tlb_all() can be a scaling issue on large SGI Altix systems
since it uses the global call_lock and always executes on all cpus.
When a process enters flush_tlb_range() to purge TLBs for another
process, it is possible to avoid flush_tlb_all() and instead allow
sn2_global_tlb_purge() to purge TLBs only where necessary.

This patch modifies flush_tlb_range() so that this case can be handled
by platform TLB purge functions and updates ia64_global_tlb_purge()
accordingly.  sn2_global_tlb_purge() now calculates the region register
value from the mm argument introduced with this patch.
Signed-off-by: NDean Roe <roe@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

bte_copy() calls calls get_nasid(), which will get flagged if
preemption if enabled.  raw_smp_processor_id() is used instead.
It is OK if we migrate off node.

Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: NTony Luck <tony.luck@intel.com>

Eliminate the passing in of a scratch buffer used for locating the
reserved page setup for XPC.
Signed-off-by: NDean Nelson <dcn@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>