Clean up the page table dumper (fix boundary conditions, table driven
address ranges, some formatting changes since it is no longer using
the kernel log but a separate virtual file), and generalize to 32
bits.

[ mingo@elte.hu: x86: fix the pagetable dumper ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch adds code to the kernel to have an (optional)
/proc/kernel_page_tables debug file that basically dumps the kernel
pagetables; this allows us kernel developers to verify that nothing fishy is
going on and that the various mappings are set up correctly. This was quite
useful in finding various change_page_attr() bugs, and is very likely to be
useful in the future as well.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: mingo@elte.hu
Cc: tglx@tglx.de
Cc: hpa@zytor.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Unify arch/x86/mm/Makefile between 32 and 64 bits.

All configuration variables that are protected by Kconfig constraints
have been put in the common part of the Makefile; however, the NUMA
files are totally different between 32 and 64 bits and are handled via
an ifdef.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Add debug information for DEBUG_PAGEALLOC to get some statistics about
the pool usage and split status.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

We map a VMA for the 32-bit vDSO even when it's disabled, which is stupid.
For the 32-bit kernel it's the vdso_enabled boot parameter/sysctl
and for the 64-bit kernel it's the vdso32 boot parameter/syscall32 sysctl.

When it's disabled, we don't pass AT_SYSINFO_EHDR so processes don't use
the vDSO for anything, but we still map it.  For the non-compat vDSO,
this means we're always putting an extra VMA somewhere, maybe lousing
up the control of the address space the user was hoping for.

Honor the setting by doing nothing in arch_setup_additional_pages.

[ also see: "x86 vDSO: don't use disabled vDSO for signal trampoline" ]
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If the vDSO was not mapped, don't use it as the "restorer" for a signal
handler.  Whether we have a pointer in mm->context.vdso depends on what
happened at exec time, so we shouldn't check any global flags now.

Background:

Currently, every 32-bit exec gets the vDSO mapped even if it's disabled
(the process just doesn't get told about it).  Because it's in fact
always there, the bug that this patch fixes cannot happen now.  With
the second patch, it won't be mapped at all when it's disabled, which is
one of the things that people might really want when they disable it (so
nothing they didn't ask for goes into their address space).

The 32-bit signal handler setup when SA_RESTORER is not used refers to
current->mm->context.vdso without regard to whether the vDSO has been
disabled when the process was exec'd.  This patch fixes this not to use
it when it's null, which becomes possible after the second patch. (This
never happens in normal use, because glibc's sigaction call uses
SA_RESTORER unless glibc detected the vDSO.)
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

people sometimes do crazy stuff like building really large static
arrays into their kernels or building allyesconfig kernels. Give
more space to the kernel and push modules up a bit: kernel has
512 MB and modules have 1.5 GB.

Should be enough for a few years ;-)
Signed-off-by: NIngo Molnar <mingo@elte.hu>

these build-time and link-time checks would have prevented the
vmlinux size regression.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix bogus pirq warnings reported in:

  http://bugzilla.kernel.org/show_bug.cgi?id=10366

safe to be backported to v2.6.25 and earlier.

Cc: stable@kernel.org
Signed-off-by: NBjörn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

http://bugzilla.kernel.org/show_bug.cgi?id=10124

this change:

      commit 08f1c192
      Author: Muli Ben-Yehuda <muli@il.ibm.com>
      Date:   Sun Jul 22 00:23:39 2007 +0300

         x86-64: introduce struct pci_sysdata to facilitate sharing of ->sysdata

         This patch introduces struct pci_sysdata to x86 and x86-64, and
         converts the existing two users (NUMA, Calgary) to use it.

         This lays the groundwork for having other users of sysdata, such as
         the PCI domains work.

         The Calgary bits are tested, the NUMA bits just look ok.

replaces pcibios_scan_root by pci_scan_bus_parented...

but in pcibios_scan_root we have a check about scanned busses.

Cc: <yakui.zhao@intel.com>
Cc: Stian Jordet <stian@jordet.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <greg@kroah.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Yinghai Lu" <yhlu.kernel@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The prevent_tail_call() macro works around the problem of the compiler
clobbering argument words on the stack, which for asmlinkage functions
is the caller's (user's) struct pt_regs.  The tail/sibling-call
optimization is not the only way that the compiler can decide to use
stack argument words as scratch space, which we have to prevent.
Other optimizations can do it too.

Until we have new compiler support to make "asmlinkage" binding on the
compiler's own use of the stack argument frame, we have work around all
the manifestations of this issue that crop up.

More cases seem to be prevented by also keeping the incoming argument
variables live at the end of the function.  This makes their original
stack slots attractive places to leave those variables, so the compiler
tends not clobber them for something else.  It's still no guarantee, but
it handles some observed cases that prevent_tail_call() did not.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch also resolves hangs on boot:
	http://lkml.org/lkml/2008/2/23/263
	http://bugzilla.kernel.org/show_bug.cgi?id=10093

The bug was causing once-in-few-reboots 10-15 sec wait during boot on
certain laptops.

Earlier commit 40d6a146 added
smp_call_function in cpu_idle_wait() to kick cpus that are in tickless
idle.  Looking at cpu_idle_wait code at that time, code seemed to be
over-engineered for a case which is rarely used (while changing idle
handler).

Below is a simplified version of cpu_idle_wait, which just makes a dummy
smp_call_function to all cpus, to make them come out of old idle handler
and start using the new idle handler.  It eliminates code in the idle
loop to handle cpu_idle_wait.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

gcc expects all toplevel assembly to return to the original section type.
The code in alteranative.c does not do this. This caused some strange bugs
in sched-devel where code would end up in the .rodata section and when
the kernel sets the NX bit on all .rodata, the kernel would crash when
executing this code.

This patch adds a .previous marker to return the code back to the
original section.

Credit goes to Andrew Pinski for telling me it wasn't a gcc bug but a
bug in the toplevel asm code in the kernel.  ;-)
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In time_cpufreq_notifier() the cpu id to act upon is held in freq->cpu. Use it
instead of smp_processor_id() in the call to set_cyc2ns_scale().
This makes the preempt_*able() unnecessary and lets set_cyc2ns_scale() update
the intended cpu's cyc2ns.

Related mail/thread: http://lkml.org/lkml/2007/12/7/130Signed-off-by: NKarsten Wiese <fzu@wemgehoertderstaat.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

revert:

| commit 47001d60
| Author: Thomas Gleixner <tglx@linutronix.de>
| Date:   Tue Apr 1 19:45:18 2008 +0200
|
|     x86: tsc prevent time going backwards

it has been identified to cause suspend regression - and the
commit fixes a longstanding bug that existed before 2.6.25 was
opened - so it can wait some more until the effects are better
understood.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We handle a broken tsc these days, so no need to panic.  We clear the
TSC bit when tsc_init decides it's unreliable (eg.  under lguest w/ bad
host TSC), leading to bogus panic.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The commits:

commit 37a47db8
Author: Balaji Rao <balajirrao@gmail.com>
Date:   Wed Jan 30 13:30:03 2008 +0100

    x86: assign IRQs to HPET timers, fix

and

commit e3f37a54
Author: Balaji Rao <balajirrao@gmail.com>
Date:   Wed Jan 30 13:30:03 2008 +0100

    x86: assign IRQs to HPET timers

have been identified to cause a regression on some platforms due to
the assignement of legacy IRQs which makes the legacy devices
connected to those IRQs disfunctional.

Revert them.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=10382Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We already catch most of the TSC problems by sanity checks, but there
is a subtle bug which has been in the code for ever. This can cause
time jumps in the range of hours.

This was reported in:
     http://lkml.org/lkml/2007/8/23/96
and
     http://lkml.org/lkml/2008/3/31/23

I was able to reproduce the problem with a gettimeofday loop test on a
dual core and a quad core machine which both have sychronized
TSCs. The TSCs seems not to be perfectly in sync though, but the
kernel is not able to detect the slight delta in the sync check. Still
there exists an extremly small window where this delta can be observed
with a real big time jump. So far I was only able to reproduce this
with the vsyscall gettimeofday implementation, but in theory this
might be observable with the syscall based version as well.

CPU 0 updates the clock source variables under xtime/vyscall lock and
CPU1, where the TSC is slighty behind CPU0, is reading the time right
after the seqlock was unlocked.

The clocksource reference data was updated with the TSC from CPU0 and
the value which is read from TSC on CPU1 is less than the reference
data. This results in a huge delta value due to the unsigned
subtraction of the TSC value and the reference value. This algorithm
can not be changed due to the support of wrapping clock sources like
pm timer.

The huge delta is converted to nanoseconds and added to xtime, which
is then observable by the caller. The next gettimeofday call on CPU1
will show the correct time again as now the TSC has advanced above the
reference value.

To prevent this TSC specific wreckage we need to compare the TSC value
against the reference value and return the latter when it is larger
than the actual TSC value.

I pondered to mark the TSC unstable when the readout is smaller than
the reference value, but this would render an otherwise good and fast
clocksource unusable without a real good reason.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Cc: xen-devel@lists.xensource.com
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

i.e. with this simple test case:

    int fd = open("/dev/zero", O_RDONLY);
    munmap(mmap((void *)0x40000000, 0x1000_LEN, PROT_READ, MAP_PRIVATE, fd, 0), 0x1000);
    close(fd);

we currently get:

   kernel BUG at arch/x86/xen/enlighten.c:678!
   ...
   EIP is at xen_release_pt+0x79/0xa9
   ...
   Call Trace:
    [<c041da25>] ? __pmd_free_tlb+0x1a/0x75
    [<c047a192>] ? free_pgd_range+0x1d2/0x2b5
    [<c047a2f3>] ? free_pgtables+0x7e/0x93
    [<c047b272>] ? unmap_region+0xb9/0xf5
    [<c047c1bd>] ? do_munmap+0x193/0x1f5
    [<c047c24f>] ? sys_munmap+0x30/0x3f
    [<c0408cce>] ? syscall_call+0x7/0xb
    =======================

and xen complains:

  (XEN) mm.c:2241:d4 Mfn 1cc37 not pinned

Further details at:

  https://bugzilla.redhat.com/436453Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Cc: xen-devel@lists.xensource.com
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Cc: xen-devel@lists.xensource.com
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix obsolete printks in aperture-64. We used not to handle missing
agpgart, but we handle it okay now.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

right now if there's no CPU support for nmi_watchdog=2 we'll just
refuse it silently.

print a useful warning.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

implement nmi_watchdog=2 on this class of CPUs:

  cpu family      : 15
  model           : 6
  model name      : Intel(R) Pentium(R) D CPU 3.00GHz

the watchdog's ->setup() method is safe anyway, so if the CPU
cannot support it we'll bail out safely.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This avoids using wrmsr on MSR_IA32_DEBUGCTLMSR when it's not needed.
No wrmsr ever needs to be done if noone has ever used block stepping.

Without this change, using ptrace on 2.6.25 on an x86 KVM guest
will tickle KVM's missing support for the MSR and crash the guest
kernel.  Though host KVM is the buggy one, this makes for a regression
in the guest behavior from 2.6.24->2.6.25 that we can easily avoid.

I also corrected some bad whitespace.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the problem that makedumpfile sometimes fails on x86_64 machine.

This patch adds the symbol "phys_base" to a vmcoreinfo data.  The
vmcoreinfo data has the minimum debugging information only for dump
filtering.  makedumpfile (dump filtering command) gets it to distinguish
unnecessary pages, and makedumpfile creates a small dumpfile.

On x86_64 kernel which compiled with CONFIG_PHYSICAL_START=0x0 and
CONFIG_RELOCATABLE=y, makedumpfile fails like the following:

 # makedumpfile -d31 /proc/vmcore dumpfile
 The kernel version is not supported.
 The created dumpfile may be incomplete.
 _exclude_free_page: Can't get next online node.

 makedumpfile Failed.
 #

The cause is the lack of the symbol "phys_base" in a vmcoreinfo data.
If the symbol "phys_base" does not exist, makedumpfile considers an
x86_64 kernel as non relocatable.  As the result, makedumpfile
misunderstands the physical address where the kernel is loaded, and it
cannot translate a kernel virtual address to physical address correctly.

To fix this problem, this patch adds the symbol "phys_base" to a
vmcoreinfo data.
Signed-off-by: NKen'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@kernel.org>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I believe http://bugzilla.kernel.org/show_bug.cgi?id=10318 is a false
positive.  There's no way in which networking will be using highmem pages
here, so it won't be taking the KM_USER0 kmap slot, so there's no point in
performing these checks.

Cc: Pawel Staszewski <pstaszewski@artcom.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
 [ Really sad.  We lose almost all real-life coverage of the debug tests
   with this patch. Now it will only report problems for the cases where
   people actually end up using a HIGHMEM page, not when they just _might_
   use one.    - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Took some cycles to re-read the Lguest Journey end-to-end, fix some
rot and tighten some phrases.

Only comments change.  No new jokes, but a couple of recycled old jokes.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Linus noticed a second bug and an uncleanliness:

 - we'd return on any instruction fetch fault

 - we'd use both the value of 16 and the PF_INSTR symbol which are
   the same and make no sense

the cleanup nicely unifies this piece of logic.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We need to set up the shared_info pointer once we've mapped the real
shared_info into its fixmap slot.  That needs to happen once the general
pagetable setup has been done.  Previously, the UP shared_info was set
up one in xen_start_kernel, but that was left pointing to the dummy
shared info.  Unfortunately there's no really good place to do a later
setup of the shared_info in UP, so just do it once the pagetable setup
has been done.

[ Stable: needed in 2.6.24.x ]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

xen_irq_enable_direct and xen_sysexit were using "andw $0x00ff,
XEN_vcpu_info_pending(vcpu)" to unmask events and test for pending ones
in one instuction.

Unfortunately, the pending flag must be modified with a locked operation
since it can be set by another CPU, and the unlocked form of this
operation was causing the pending flag to get lost, allowing the processor
to return to usermode with pending events and ultimately deadlock.

The simple fix would be to make it a locked operation, but that's rather
costly and unnecessary.  The fix here is to split the mask-clearing and
pending-testing into two instructions; the interrupt window between
them is of no concern because either way pending or new events will
be processed.

This should fix lingering bugs in using direct vcpu structure access too.

[ Stable: needed in 2.6.24.x ]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The first page of the compound page is determined in follow_huge_addr()
but then PageCompound() only checks if the page is part of a compound page.
PageHead() allows checking if this is indeed the first page of the
compound.

Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch fixes the use of GPIO routines which are in the PCI
configuration space of the RDC321x, therefore reading/writing
to this space without spinlock protection can be problematic.

We also now request and free GPIOs and support the MGB100
board, previous code was very AR525W-centric.
Signed-off-by: NVolker Weiss <volker@tintuc.de>
Signed-off-by: NFlorian Fainelli <florian.fainelli@telecomint.eu>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/ptrace.c:548: warning: 'ptrace_bts_get_size' defined but not used
arch/x86/kernel/ptrace.c:558: warning: 'ptrace_bts_read_record' defined but not used
arch/x86/kernel/ptrace.c:607: warning: 'ptrace_bts_clear' defined but not used
arch/x86/kernel/ptrace.c:617: warning: 'ptrace_bts_drain' defined but not used
arch/x86/kernel/ptrace.c:720: warning: 'ptrace_bts_config' defined but not used
arch/x86/kernel/ptrace.c:788: warning: 'ptrace_bts_status' defined but not used

Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

some early Athlon XP's and Opterons generate bogus faults on prefetch
instructions. The workaround for this regressed over .24 - reinstate it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix the 3D performance drop reported at:

   http://bugzilla.kernel.org/show_bug.cgi?id=10328

fb drivers are using ioremap()/ioremap_nocache(), followed by mtrr_add with
WC attribute. Recent changes in page attribute code made both
ioremap()/ioremap_nocache() mappings as UC (instead of previous UC-). This
breaks the graphics performance, as the effective memory type is UC instead
of expected WC.

The correct way to fix this is to add ioremap_wc() (which uses UC- in the
absence of PAT kernel support and WC with PAT) and change all the
fb drivers to use this new ioremap_wc() API.

We can take this correct and longer route for post 2.6.25. For now,
revert back to the UC- behavior for ioremap/ioremap_nocache.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

we could call find_max_pfn() directly instead of setup_memory() to get
max_pfn needed for mtrr trimming.

otherwise setup_memory() is called two times... that is duplicated...

[ mingo@elte.hu: both Thomas and me simulated a double call to
  setup_bootmem_allocator() and can confirm that it is a real bug
  which can hang in certain configs. It's not been reported yet but
  that is probably due to the relatively scarce nature of
  MTRR-trimming systems. ]
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On Wed, 26 Mar 2008 11:56:22 -0600
Jordan Crouse <jordan.crouse@amd.com> wrote:

> On 26/03/08 14:31 +0100, Stefan Pfetzing wrote:
> > Hello Jordan,
> >
> > I just tried to build your geodwdt driver for the geode watchdog. Therefore
> > I pulled your repository from http://git.infradead.org/geode.git (or more,
> > the git url).
> >
> > I tried to build the geodewdt driver as a module - which didn't work, and
> > it failed with the same problem as earlier mentioned on lkmk [1]. I also
> > checked the fix [2], but that seems to be already in your (or linus) tree -
> > and so I'm unsure what the problem is.
> >
> > [1] http://kerneltrap.org/mailarchive/linux-kernel/2008/2/17/884074
> > [2] http://kerneltrap.org/mailarchive/linux-kernel/2008/2/17/884174
> >
> > Building directly into the kernel seems to work.
> >
> > Maybe you have some idea?
>
> Hmm - that is strange.  Exporting the symbols should work.  I recommend
> starting over with a clean tree.
>
> CCing Andres - any thoughts?
>
> Jordan
>

Er, yeah.  The patch below should fix it.  This should probably go into
2.6.25.

Oops, EXPORT_SYMBOL_GPL wasn't being declared due to this header
being missing.
Signed-off-by: NAndres Salomon <dilinger@debian.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

I have found that using SMI to change the cpu's frequency on my DELL
Latitude L400 clobbers the ECX register in speedstep_set_state, causing
unneccessary retries because the "state" variable has changed silently (GCC
assumes it is still present in ECX).

play safe and avoid gcc caching any register across IO port accesses
that trigger SMIs.

Signed-off by: <Stephan.Diestelhorst@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix oops during boot reported in this thread:

  http://lkml.org/lkml/2008/2/6/65

enable booting on memoryless nodes.
Reported-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>