x2apic cluster mode support.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Introduce self IPI op for genapic.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x2apic ops for x2apic mode support. This uses MSR interface and differs
slightly from the xapic register layout.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

cpuid feature for x2apic.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Introduce basic apic operations which handle the apic programming. This
will be used later to introduce another specific operations for x2apic.

For the perfomance critial accesses like IPI's, EOI etc, we use the
native operations as they are already referenced by different
indirections like genapic, irq_chip etc.

64bit Paravirt ops can also define their apic operations accordingly.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Yinghai Lu wrote:

> Setting APIC routing to physical flat
> Kernel panic - not syncing: Boot APIC ID in local APIC unexpected (0 vs 4)
> Pid: 1, comm: swapper Not tainted 2.6.26-rc9-tip-01763-g74f94b1-dirty #320
>
> Call Trace:
>  [<ffffffff80a21505>] ? set_cpu_sibling_map+0x38c/0x3bd
>  [<ffffffff80245215>] ? read_xapic_id+0x25/0x3e
>  [<ffffffff80e5a2c3>] ? verify_local_APIC+0x139/0x1b9
>  [<ffffffff80245215>] ? read_xapic_id+0x25/0x3e
>  [<ffffffff80e589af>] ? native_smp_prepare_cpus+0x224/0x2e9
>  [<ffffffff80e4881a>] ? kernel_init+0x64/0x341
>  [<ffffffff8022a439>] ? child_rip+0xa/0x11
>  [<ffffffff80e487b6>] ? kernel_init+0x0/0x341
>  [<ffffffff8022a42f>] ? child_rip+0x0/0x11
>
>
> guess read_apic_id changing cuase some problem...

genapic's read_apic_id() returns the actual apic id extracted from
the APIC_ID register. And in some cases like UV, read_apic_id()
returns completely different values from APIC ID register.

Use the native apic register read, rather than genapic read_apic_id()
in verify_local_APIC()

And also, lapic_suspend() should also use native apic register read.
Reported-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "arjan@linux.intel.com" <arjan@linux.intel.com>
Cc: "andi@firstfloor.org" <andi@firstfloor.org>
Cc: "ebiederm@xmission.com" <ebiederm@xmission.com>
Cc: "jbarnes@virtuousgeek.org" <jbarnes@virtuousgeek.org>
Cc: "steiner@sgi.com" <steiner@sgi.com>
Cc: "jeremy@goop.org" <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move the read_apic_id()  to genapic routines.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Generic ioapic specific routines which be used later during enabling
interrupt-remapping.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

8259 specific mask/unmask routines which be used later while enabling
interrupt-remapping.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On three of the several paths in entry_64.S that call
do_notify_resume() on the way back to user mode, we fail to properly
check again for newly-arrived work that requires another call to
do_notify_resume() before going to user mode.  These paths set the
mask to check only _TIF_NEED_RESCHED, but this is wrong.  The other
paths that lead to do_notify_resume() do this correctly already, and
entry_32.S does it correctly in all cases.

All paths back to user mode have to check all the _TIF_WORK_MASK
flags at the last possible stage, with interrupts disabled.
Otherwise, we miss any flags (TIF_SIGPENDING for example) that were
set any time after we entered do_notify_resume().  More work flags
can be set (or left set) synchronously inside do_notify_resume(), as
TIF_SIGPENDING can be, or asynchronously by interrupts or other CPUs
(which then send an asynchronous interrupt).

There are many different scenarios that could hit this bug, most of
them races.  The simplest one to demonstrate does not require any
race: when one signal has done handler setup at the check before
returning from a syscall, and there is another signal pending that
should be handled.  The second signal's handler should interrupt the
first signal handler before it actually starts (so the interrupted PC
is still at the handler's entry point).  Instead, it runs away until
the next kernel entry (next syscall, tick, etc).

This test behaves correctly on 32-bit kernels, and fails on 64-bit
(either 32-bit or 64-bit test binary).  With this fix, it works.

    #define _GNU_SOURCE
    #include <stdio.h>
    #include <signal.h>
    #include <string.h>
    #include <sys/ucontext.h>

    #ifndef REG_RIP
    #define REG_RIP REG_EIP
    #endif

    static sig_atomic_t hit1, hit2;

    static void
    handler (int sig, siginfo_t *info, void *ctx)
    {
      ucontext_t *uc = ctx;

      if ((void *) uc->uc_mcontext.gregs[REG_RIP] == &handler)
        {
          if (sig == SIGUSR1)
            hit1 = 1;
          else
            hit2 = 1;
        }

      printf ("%s at %#lx\n", strsignal (sig),
              uc->uc_mcontext.gregs[REG_RIP]);
    }

    int
    main (void)
    {
      struct sigaction sa;
      sigset_t set;

      sigemptyset (&sa.sa_mask);
      sa.sa_flags = SA_SIGINFO;
      sa.sa_sigaction = &handler;

      if (sigaction (SIGUSR1, &sa, NULL)
          || sigaction (SIGUSR2, &sa, NULL))
        return 2;

      sigemptyset (&set);
      sigaddset (&set, SIGUSR1);
      sigaddset (&set, SIGUSR2);
      if (sigprocmask (SIG_BLOCK, &set, NULL))
        return 3;

      printf ("main at %p, handler at %p\n", &main, &handler);

      raise (SIGUSR1);
      raise (SIGUSR2);

      if (sigprocmask (SIG_UNBLOCK, &set, NULL))
        return 4;

      if (hit1 + hit2 == 1)
        {
          puts ("PASS");
          return 0;
        }

      puts ("FAIL");
      return 1;
    }
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We have two conflicting DMA-based quirks in there for the same set of
boxes (HP nx6325 and nx6125) and one of them actually breaks my box.

So remove the extra code.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: =?iso-8859-1?q?T=F6r=F6k_Edwin?= <edwintorok@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In the course of the recent unification of the NMI watchdog an assignment
to timer_ack to switch off unnecesary POLL commands to the 8259A in the
case of a watchdog failure has been accidentally removed.  The statement
used to be limited to the 32-bit variation as since the rewrite of the
timer code it has been relevant for the 82489DX only.  This change brings
it back.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

There is no such entity as ISA IRQ2.  The ACPI spec does not make it
explicitly clear, but does not preclude it either -- all it says is ISA
legacy interrupts are identity mapped by default (subject to overrides),
but it does not state whether IRQ2 exists or not.  As a result if there is
no IRQ0 override, then IRQ2 is normally initialised as an ISA interrupt,
which implies an edge-triggered line, which is unmasked by default as this
is what we do for edge-triggered I/O APIC interrupts so as not to miss an
edge.

To the best of my knowledge it is useless, as IRQ2 has not been in use
since the PC/AT as back then it was taken by the 8259A cascade interrupt
to the slave, with the line position in the slot rerouted to newly-created
IRQ9.  No device could thus make use of this line with the pair of 8259A
chips.  Now in theory INTIN2 of the I/O APIC may be usable, but the
interrupt of the device wired to it would not be available in the PIC mode
at all, so I seriously doubt if anybody decided to reuse it for a regular
device.

However there are two common uses of INTIN2.  One is for IRQ0, with an
ACPI interrupt override (or its equivalent in the MP table).  But in this
case IRQ2 is gone entirely with INTIN0 left vacant.  The other one is for
an 8959A ExtINTA cascade.  In this case IRQ0 goes to INTIN0 and if ACPI is
used INTIN2 is assumed to be IRQ2 (there is no override and ACPI has no
way to report ExtINTA interrupts).  This is where a problem happens.

The problem is INTIN2 is configured as a native APIC interrupt, with a
vector assigned and the mask cleared.  And the line may indeed get active
and inject interrupts if the master 8959A has its timer interrupt enabled
(it might happen for other interrupts too, but they are normally masked in
the process of rerouting them to the I/O APIC).  There are two cases where
it will happen:

* When the I/O APIC NMI watchdog is enabled.  This is actually a misnomer
  as the watchdog pulses are delivered through the 8259A to the LINT0
  inputs of all the local APICs in the system.  The implication is the
  output of the master 8259A goes high and low repeatedly, signalling
  interrupts to INTIN2 which is enabled too!

  [The origin of the name is I think for a brief period during the
  development we had a capability in our code to configure the watchdog to
  use an I/O APIC input; that would be INTIN2 in this scenario.]

* When the native route of IRQ0 via INTIN0 fails for whatever reason -- as
  it happens with the system considered here.  In this scenario the timer
  pulse is delivered through the 8259A to LINT0 input of the local APIC of
  the bootstrap processor, quite similarly to how is done for the watchdog
  described above.  The result is, again, INTIN2 receives these pulses
  too.  Rafael's system used to escape this scenario, because an incorrect
  IRQ0 override would occupy INTIN2 and prevent it from being unmasked.

My conclusion is IRQ2 should be excluded from configuration in all the
cases and the current exception for ACPI systems should be lifted.  The
reason being the exception not only being useless, but harmful as well.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
the "8259A Virtual Wire" through the local APIC timer configuration does
not fully configure the relevant irq_chip structure.  Instead it relies on
the preceding I/O APIC code to have set it up, which does not happen if
the I/O APIC variants have not been tried.

The patch includes corresponding changes to the 32-bit variation too
which make them both the same, barring a small syntactic difference
involving sequence of functions in the source.  That should work as an aid
with the upcoming merge.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

 IRQ0 is edge-triggered, but the "8259A Virtual Wire" through the local
APIC configuration in the 32-bit version uses the "fasteoi" handler
suitable for level-triggered APIC interrupt.  Rewrite code so that the
"edge" handler is used.  The 64-bit version uses different code and is
unaffected.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The RING0_INT_FRAME macro defines a CFI_STARTPROC.
So we should really be using CFI_ENDPROC after it.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add pseudo-feature bits to describe whether the CPU supports sysenter
and/or syscall from ia32-compat userspace.  This removes a hardcoded
test in vdso32-setup.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Yinghai Lu reported crashes on 64-bit x86:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
 IP: [<ffffffff80253b17>] hrtick_start_fair+0x89/0x173
 [...]

And with a long session of debugging and a lot of difficulty, tracked it down
to this commit:

 --------------->
 8fbbc4b4 is first bad commit
 commit 8fbbc4b4
 Author: Alok Kataria <akataria@vmware.com>
 Date:   Tue Jul 1 11:43:34 2008 -0700

     x86: merge tsc_init and clocksource code
 <--------------

The problem is that the TSC unification missed these Makefile rules
in arch/x86/kernel/Makefile:

  # Do not profile debug and lowlevel utilities
  CFLAGS_REMOVE_tsc_64.o = -pg
  CFLAGS_REMOVE_tsc_32.o = -pg
  ...
  CFLAGS_tsc_64.o         := $(nostackp)
  ...

which rules make sure that various instrumentation and debugging
facilities are disabled for code that might end up in a VDSO - such as
the TSC code.
Reported-and-bisected-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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

when more than 4g memory is installed, don't map the big hole below 4g.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

also let mem= to print out modified e820 map too
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Bernhard Walle <bwalle@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Integration generated a duplicate call to use_tsc_delay.
Particularly, the one that is done before we check for general
tsc usability seems wrong.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix:

arch/x86/kernel/visws_quirks.c: In function ‘visws_early_detect’:
arch/x86/kernel/visws_quirks.c:293: error: ‘no_broadcast’ undeclared (first use in this function)
arch/x86/kernel/visws_quirks.c:293: error: (Each undeclared identifier is reported only once
arch/x86/kernel/visws_quirks.c:293: error: for each function it appears in.)
make[1]: *** [arch/x86/kernel/visws_quirks.o] Error 1
make: *** [arch/x86/kernel/visws_quirks.o] Error 2
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NDaniel Guilak <daniel@danielguilak.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

merge traps_visws.c and apic_visws.c into visws_quirks.c.

(no code changed)
Signed-off-by: NIngo Molnar <mingo@elte.hu>

rename setup_visws.c to visws_quirks.c.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

skip IO-APIC setup on a VISWS if it's enabled.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

this is the big move: flip over VISWS to generic arch support.

From this commit on CONFIG_X86_VISWS is just another (default-disabled)
option that turns on certain quirks - no other complications.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

copy arch/x86/mach-visws/setup_visws.c, apic_visws.c and traps_visws.c
files to arch/x86/kernel/, in preparation of the switchover to a
non-subarch setup for VISWS.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

first step: make the VISWS subarch boot on a regular PC.

We take various shortcuts for that. We copy the generic arch setup file over
into the VISWS setup file.

This is the only step that is not expected to boot on a real VISWS.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add early quirks support.

In preparation of enabling the generic architecture to boot on a VISWS.

This will allow us to remove the VISWS subarch and all its complications.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When an interrupt is rerouted to a different I/O APIC pin the relevant
entry of the irq_2_pin list should get updated accordingly so that
operations are performed on the correct redirection entry.

This is already done by the 32-bit variation of the code and here is a
complementing 64-bit implementation.  Should make someone's decision less
tough when merging the two. ;)
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This reverts commit 90221a61a71b7ad659d8741cf1e404506b174982.

This too was just temporary diagnostics - not needed now that we've
got the final fix via:

| commit e2079c43
| Author: Rafael J. Wysocki <rjw@sisk.pl>
| Date:   Tue Jul 8 16:12:26 2008 +0200
|
|     x86: fix C1E && nx6325 stability problem
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This reverts commit a74a1cc3df0be89658bc735c8aed80c8392e2c15.

This was just temporary diagnostics commit - not needed now that we've
got the final fix.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

even on 64bit systems with less than 4G RAM, we can now use fixmap
to handle acpi SIT near end of ram.

change e820_end to e820_end_of_ram again?
or e820_ram_pfn?
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

and let 64-bit to fall back to use fixmap too.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: akpm@linux-foundation.org
Cc: andi@firstfloor.org
Signed-off-by: NIngo Molnar <mingo@elte.hu>

to avoid warning from find_low_pfn_range for high pages size etc
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix:

arch/x86/kernel/acpi/boot.c: In function ‘dmi_ignore_irq0_timer_override’:
arch/x86/kernel/acpi/boot.c:1443: error: implicit declaration of function ‘force_mask_ioapic_irq_2’
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The problems are that, with the ACPI vs timer overring issue _fixed_,
after using the box for some time (between several seconds and 1 hour, at
random) processes get very high CPU loads (once I've got X using 107% of
the CPU, for example) and the system becomes unresponsive, as though there
were interrupts lost or something similar.

Andreas Herrman reproduced similar problems:

> Ok, now I've reproduced the stability problem.
> - Using tip/master,
> - reverting e38502eb8aa82314d5ab0eba45f50e6790dadd88 and
> - applying your patch from this posting
>   http://marc.info/?l=linux-kernel&m=121539354224562&w=4
>
> Starting X, firefox, gimp, tuxpaint and doing some drawing in tuxpaint
> results in a slow system. Drawing is almost not possible anymore --
> Selections of new colors, cursors etc. is performed with huge delay
> if it's performed at all.
>
> BTW, the code sets up timer IRQ as Virtual Wire IRQ:
>
> Jul  8 14:57:58 kodscha IO-APIC (apicid-pin) 2-22, 2-23 not connected.
> Jul  8 14:57:58 kodscha ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> Jul  8 14:57:58 kodscha ...trying to set up timer as Virtual Wire IRQ... works.
>
> and both INT0 and INT2 of IOAPIC are masked:
>
> Jul  8 14:57:58 kodscha NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:
> Jul  8 14:57:58 kodscha 00 000 1    0    0   0   0    0    0    00
> Jul  8 14:57:58 kodscha 01 003 0    0    0   0   0    1    1    31
> Jul  8 14:57:58 kodscha 02 003 1    0    0   0   0    0    0    30
>
> I've also seen strange CPU utilization -- with syslog-ng:
>
> top - 15:33:06 up 35 min,  4 users,  load average: 1.70, 0.68, 0.37
> Tasks:  64 total,   4 running,  60 sleeping,   0 stopped,   0 zombie
> Cpu0  :  0.0%us,100.0%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
> Cpu1  :  6.4%us, 87.2%sy,  0.0%ni,  5.8%id,  0.0%wa,  0.6%hi,  0.0%si,  0.0%st
> Mem:    895384k total,   283568k used,   611816k free,    35492k buffers
> Swap:  1959920k total,        0k used,  1959920k free,   163044k cached
>
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>  4632 root      20   0 17216  800  580 S  104  0.1   0:34.22 syslog-ng
> 28505 root      20   0  205m  11m 4024 S    6  1.3   0:21.16 X
> 28518 root      20   0 56292 5652 4492 S    1  0.6   0:01.80 fluxbox
>     1 root      20   0  3724  608  508 S    0  0.1   0:00.36 init
>
> So far I have no clue why C1E-idle in conjunction with virtual wire
> mode causes this strange behaviour.
>
> ... and I start to think about the root cause of all this.
>
> I've performed similar tests under X with the IRQ0/INT0 configuration and
> I did not see above symptoms.

So lets fall back to the IRQ0/INT0 configuration on this box.

This basically restores the dont-use-the-lapic-timer exception mechanism
that was unconditional on this box prior commit 8750bf5 ("x86: add C1E
aware idle function").
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When system have 4g less ram installed, and acpi table sit
near end of ram, make max_pfn cover them too,
so 64bit kernel don't need to mess up fixmap.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: "Suresh Siddha" <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>